KR101658975B1

KR101658975B1 - Ion source cleaning in semiconductor processing systems

Info

Publication number: KR101658975B1
Application number: KR1020117020918A
Authority: KR
Inventors: 요셉 디 스위니; 샤라드 엔 예다베; 올레그 빌; 로버트 카임; 데이비드 엘드릿지; 린 펭; 스티븐 이 비숍; 더블유 칼 올랜더; 잉 탕
Original assignee: 엔테그리스, 아이엔씨.
Priority date: 2009-02-11
Filing date: 2009-08-12
Publication date: 2016-09-23
Also published as: TW201030792A; CN104217981A; EP2396809A1; KR20110128848A; SG173621A1; TW201438052A; WO2010093380A1; TWI463516B; TWI567775B; CN104217981B; CN102396048A; CN102396048B

Abstract

The present invention enables cathodic growth / etching in indirectly heated cathodes for ion implantation systems by monitoring the cathode bias power and taking corrective action according to the compared values to etch or regrow the cathodes. To a cleaning of the ion implantation system or components thereof using a reactive cleaning agent and /

Description

[0001] ION SOURCE CLEANING IN SEMICONDUCTOR PROCESSING SYSTEMS [0002]

The present invention relates to the monitoring, control and cleaning of components of a semiconductor processing system, particularly the deposition of materials in an ion implantation system.

Ion implantation is used in integrated circuit fabrication to accurately introduce controlled amounts of dopant impurities into semiconductor wafers and is an important process in microelectronics / semiconductor manufacturing. In such an injection system, the ion source ionizes the desired dopant element gas and extracts the ions from the source in the form of an ion beam of desired energy. Extraction is accomplished by applying a high voltage across an appropriately shaped extraction electrode, including an aperture for the passage of the extracted beam. The ion beam is then directed directly to a product, such as a semiconductor wafer, to implant the dopant component into the workpiece. The ion beam penetrates the surface of the workpiece to form a desired conductive region.

Various types of ion sources include Freeman and Bernas types powered by electric arc and using thermal electrodes, microwave types using magnetron, indirectly heated cathode sources, and RF < RTI ID = 0.0 > Are commonly used in commercial ion implantation systems, including plasma sources, all of which operate in a vacuum in general. The ion source generates ions by introducing electrons into a vacuum chamber filled with a dopant gas (commonly referred to as a "feedstock gas"). The collision of electrons with dopant atoms and gaseous molecules results in an ionized plasma consisting of positive and negative dopant ions. An extraction electrode with a positive or negative propensity will cause each positive or negative ion to exit the ion source as a collimated ion beam accelerated toward the workpiece through the perforations. The feedstock gas is _{BF 3, B 1O H 14,} B 18 H 22, PH 3, AsH 3, PF 5, AsF 5, H 2 Se, N 2, Ar, GeF 4, SiF 4, O 2, H 2, and include GeH _4, but are not limited to this.

Currently, there are 10 to 15 or more injection steps in the manufacture of devices at the state of the art level. With respect to better process control, the transmission of high beam currents at low energy and the reduction in mean time between failures (MTBF), as the wafer size increases and as the critical dimension decreases, As complexity increases, more demands are placed on ion implantation equipment.

An ion implanter equipment component that requires good maintenance is an ion source that must be maintained after about 100 to 300 hours of operation depending on operating conditions; Extraction electrodes and high voltage insulators, which typically require cleaning after several hundred hours of operation; Ion source turbo pumps and associated forines, as well as vacuum pumps and forerunners of ion implantation vacuum systems. Additionally, various components of the ion source, such as filaments, cathodes, etc., may require replacement after operation.

In an ideal case, all the feedstock molecules will be ionized and extracted, but in practice, a certain amount of feedstock decomposition occurs, resulting in deposition and contamination in the ion source region. For example, phosphorus residues (derived from the use of a feedstock gas such as, for example, phosphine) are readily deposited on the surface of the ion source region. The residue may form a low-voltage insulator of the ion source, resulting in electrical short circuits, and may interfere with the arc required to produce thermionic electrons. This phenomenon is commonly known as "source glitching" and is a major factor in ion beam instability and may eventually lead to premature failure of the source. The residue is also formed on the high voltage component of the ion implanter, such as the surface of the source insulator or extraction electrode, resulting in energy high voltage sparking. The spark is another factor in beam instability, and the energy released by the spark damages sensitive electronic components, resulting in increased equipment defects and poor MTBF.

Another common problem may be exacerbated by flowing a boron (B) can occur when an antimony (Sb ⁺⁾ implantation that uses the Sb ₂ O _3, which can even just after Sb ⁺ injection time as a solid dopant material. The boron beam current has a significant adverse effect on the performance and lifetime of the ion source, and is not significantly exhibited. This deterioration in performance is due to excessive Sb deposited on the source chamber and their components. Ion source depletion significantly reduces injector productivity because throughput is reduced due to more frequent preventive maintenance or lower beam currents. Since Sb implantation is widely used in analog dipole devices and is also used as an n-type dopant for shallow junctions for metal oxide semiconductor (MOS) devices, in the art where Sb ⁺ is used as a dopant, There is a need to develop a method that can remove Sb deposited on the source chamber and their components, especially when switched to B after Sb implantation.

In addition, dopant atoms such as B, Ge, Si, P and As can be deposited in the downstream ion source turbo pump in the associated vacuum foreline and in a roughing pump located downstream of the foreline. Over time, these deposits have accumulated and historically manual cleaning has been required. However, some deposits (e. G., Solid) are pyrophoric and can ignite during manual maintenance operations. It can escape harmful compounds as well as fire hazards. Thus, in the art, situ & lt ; / RTI & gt ; deposits.

In another source of ion source depletion, a variety of materials (e.g., tungsten, W) may be deposited on the cathode during long ion implantation processes. When they reach the critical level, the cathode power can no longer maintain a temperature sufficient to satisfy the set point of the beam current. This causes loss of the ion beam current, which requires replacement of the ion source. The deterioration and short life of the resulting ion source reduces the productivity of the ion implantation system.

Another case of ion source depletion is corrosion (or sputtering) of the cathode material. For example, metallic materials (e.g., W, Mo, etc.) from the cathode are sputtered by ions in the plasma in the chamber. Since the sputtering is dominated by the largest ions in the plasma, the larger the ion mass, the worse the sputtering effect is. In fact, continuous sputtering of the material makes the cathode thinner and eventually forms a through-hole in the cathode (cathode punch-through). As a result, the performance and lifetime of the ion source are greatly reduced. Thus, the art continues to find a way to balance the corrosion and accumulation of materials on the cathode in order to prolong the life of the ion source.

Additionally, the residues can be derived from reactions between the components of the ion implantation system and the source material, depending on the internal conditions of the system. Such a reaction may cause deposition of residues on additional components of the system. For example, tungsten whiskers are formed on the arc chamber extraction perforations, resulting in beam non-uniformity problems.

Deposits are common in ion source components, such as filaments and reflective electrodes. These internal deposits are generally composed of arc chamber materials, and fluorine source feedstock together with arc chambers comprised of tungsten or molybdenum are most commonly observed when performed with plasma power. The ion source life expectancy for an ion implantation system using a non-halide-containing source material is generally about 100 to 300 hours, and for some halide-containing materials, such as GeF ₄ , And can be as low as 10 to 50 hours due to the adverse effects of internal deposits.

In addition to the operational difficulties caused by the residues of the ion implanter, there is also a considerable stability problem of the individual that is important due to the release of toxic or corrosive vapors when the components are removed for cleaning. The stability problem arises wherever the residue is present, but is particularly relevant to the ion source region since the ion source is the most frequently managed component of the ion implanter. To minimize the down-time, the contaminated ion source is sometimes removed from the injector at a temperature significantly higher than room temperature, increasing the ejection of the vapor and exacerbating the stability problem.

Conventional methods of dealing with this difficulty include the formation of deposits and attempts to prevent cleaning of deposits generated on the extraction electrodes and ion sources (i.e., US Patent Application Publication No. 2006/0272776, US Patent Publication 2006 / 0272775 and on extraction electrodes, as discussed in International Patent Publication WO 2005/059942 A2). However, there remains a need for additional cleaning processes for all elements of the ion implantation system.

Therefore, the ion implantation technique is performed at a position other than the original position ( ex situ) is desirable to provide a separate cleaning station (station) in the washing step and, thereby, the contaminated components removed from the injector, to be safely cleaned without can damage the sensitive components, such as graphite electrodes for any mechanical wear that . Thus, providing an off-line cleaning station that can be used for selective and non-destructive cleaning components after removal from the injection system with minimal downtime is a significant development in the per-ion implantation technology .

It would also be a significant advancement in ion implantation technology to provide an in-situ cleaning process for effective and selective removal of undesired residues deposited throughout the implanter, especially the ion source region, during implantation. Such in-situ cleaning will improve the stability of the individual and will contribute to the safe and uninterrupted operation of the injection device.

The in-situ cleaning process is performed without disassembly of the process chamber. In the in-situ process, the gaseous reagent flows through the process chamber and can remove the accumulated film in a continuous pulse format or in a hybrid continuous pulse format. Plasma may or may not occur during this cleaning.

A dry cleaning process using chlorine trifluoride (ClF ₃ ) and other fluorine source materials (for example, CF ₄ NF ₃ , C ₂ F ₆₁ C ₃ F ₈ , SF ₆ and ClF ₃ ), or a plasmaless ) Can remove solid residues from semiconductor processing chambers, for example, by reacting with solid residues to form volatile reaction products that can be removed from the process chamber under vacuum or other removal conditions, and in this example, May require elevated cleaning conditions (Y. Saito et < RTI ID = 0.0 > al ., "Plasmaless Cleaning Process of Silicon Surface Using Chlorine Trifluoride ", APPLIED PHYSICS LETTERS, vol. 56 (8), pp. 1119-1121 (1990); And DE Ibbotson et al ., "Plasmaless Dry Etching of Silicon with Fluorine-Containing Compounds ", JOURNAL OF APPLIED PHYSICS, vol. 56 (10), pp. 2939-2942 (1984)).

U.S. Patent No. 4,498,953 discloses a _{BrF 5, BrF 3, ClF 3} , or the cleaning method circle flowing continuously position the halogen intermetallic compound through the process chamber, such as IF ₅ while a predetermined pressure in the chamber maintained . At the end of the treatment, the flow of the interhalogen compound gas is also terminated. This process can produce fluorine-containing byproducts as well as Cl, Br, or I-containing byproducts to generate significant amounts of hazardous waste requiring treatment or other disposition. In addition, such continuous flow cleaning is performed under very low pressure conditions where the cleaning efficiency is substantially reduced.

In some ion source applications, strategic sequencing of BF ₃ , PH _3, and / or AsH ₃ has been performed to obtain a longer ion source lifetime.

The use of fluorine radicals or fluorine-containing interhalogen compounds for cleaning semiconductor process equipment has associated associations that limit their commercial viability. The supply of fluorine radicals or fluorine-containing interhalogens containing ClF ₃ is highly corrosive. Interhalogen compounds stimulate the human respiratory system extremely. For example, the threshold level of human resistance to ClF ₃ vapors is as low as 100 ppb and the LC 50 per hour is about 300 ppm.

There is a continuing need in the art for new cleaners and systems and processes in in-and out-of-place and in-situ, and related monitoring and control devices and methods.

The present invention generally relates to compositions and methods useful for cleaning, as well as devices and methods for monitoring, controlling and cleaning ion implant systems or components thereof.

In one aspect, the present invention provides a method of manufacturing a plasma processing chamber, comprising: (a) energizing a filament in an arc chamber of an ion source using an initial current sufficient to generate a plasma within the arc chamber; (b) measuring an applied current to the filament to hold the plasma in the arc chamber at a predetermined time during subsequent plasma generation; (c) comparing the applied current measured at the predetermined time with the initial current; And (d) determining from the comparison whether a material has been deposited on the filament or if etching of the filament has occurred, wherein a greater current in the predetermined time zone relative to the initial current is applied to the filament And wherein a smaller current at said predetermined time period relative to said initial current indicates an etching of the filament, wherein said current is indicative of deposition of material, .

In another aspect, the present invention provides a method comprising: (a) energizing a filament in an arc chamber of an ion source using an initial current sufficient to generate a plasma in the arc chamber; (b) measuring an applied current to the filament to hold the plasma in the arc chamber at a predetermined time during subsequent plasma generation; (c) comparing the applied current measured at the predetermined time with the initial current; (d) determining from the comparison whether a substance has been deposited on the filament, or whether etching of the filament has occurred, wherein a greater current in the predetermined time zone relative to the initial current is applied to the filament Wherein the smaller current in the predetermined time zone relative to the initial current indicates the etching of the filament; And (e) in response to the determination, removing the deposited material from the filament or depositing additional material on the filament, to an extent that resets the initial current or the current within a predetermined range of the initial current A method for controlling the conditions of the filaments of the system during operation of the ion implantation system. In another aspect of this embodiment, steps (a) - (d) may be performed during the ion implantation process, and step (e) may be performed before, after, or during the ion implantation process.

In yet another aspect, the present invention provides a method comprising: (a) determining a power usage for an indirectly heated cathode supply by measuring a cathode bias power supply at a predetermined time; (b) comparing the power usage at a predetermined time with an initial power; (c) in response to the comparison, to indirectly control the condition of the heated cathode, (i) etching the indirectly heated cathode if the power usage at the predetermined time zone is higher than the initial power, or (ii) (IHC) source of the ion implantation system during operation of the system, including the step of taking a corrective action to regenerate the indirectly heated cathode if the power usage at the predetermined time zone is lower than the initial power. Lt; / RTI > The initial power includes the value of the cathode bias power at the time the measurement is made at the scheduled time, for example, it may be the power at the start or the power under normal process conditions, or any other pre- - May be a set point. As will be understood by those skilled in the art, the cathode bias power measurement and initial power value may be in the form of ranges or ranges depending on the implantation process or other environment. The etching of step (c) (i) comprises manipulating the indirectly heated cathode under conditions from low to intermediate temperatures sufficient to etch. In this regard, the low to intermediate temperatures are exemplified by about room temperature to about 2000 < 0 > C. Re-growth of (ii) of step (c) is up indirectly the cathode heated to include Sikkim flowing a fluorinated gas in a plasma state, wherein the fluorinated gas is XeF _2, XeF _4, XeF _6, GeF _4, SiF _{4, BF 3, AsF 5,} AsF 3, PF 5, PF 3, F 2, TaF 3, TaF 5, WF 6, WF 5, WF 4, NF 3, IF 5, IF 7, KrF 2, SF 6, _{C 2 F 6, CF 4,} ClF 3, N 2 F 4, N 2 F 2, N 3 F, NFH 2, NH 2 F, BrF 3, C 3 F 8, C 4 F 8, C 5 F 8, _{CHF 3, CH 2 F 2,} CH 3 F, COF 2, HF, C 2 HF 5, C 2 H 2 F 4, C 2 H 3 F 3, C 2 H 4 F 2, C 2 H 5 F, C ₃ F ₆ , and MoF ₆ . Regrowth in (ii) of step (c) involves manipulating the indirectly heated cathode at a high enough temperature to cause metal deposition to occur. High temperatures associated therewith are exemplified above 2000 ° C. Correction step (c) may be performed before the ion implantation process, after the ion implantation process, or during the ion implantation process. Additionally, in the case of regrowth, the correction step can be performed during the implantation process, if selected from one of the fluorine gases described just before the injected paper. The steps of the method described above or elsewhere herein may be performed in a manner that allows for the automatic repair or cleaning of the components of the ion source, e.g., filament, repeller electrode, cathode, and anti- Electronic and / or electromechanical components, which are programmed and / or set up by a suitable control device, such as a microcontroller, regulator, microprocessor, etc., and associated electrical, electronic and / or electromechanical components.

In another aspect, the present invention provides a method of forming a tungsten film, comprising: (a) performing a tungsten deposition on a filament; And (b) contacting the filament, or a cathode or other part of the ion source, as described above with a tungsten reagent under conditions selected from the group consisting of conditions for performing etching of the deposited material from the filament. (Or other components of an ion source that may be etched or deposited, such as, but not limited to, an anti-cathode, a repeller, etc.) within the arc chamber of the ion source to maintain the operating efficiency of the ion source. A method of operating an ion implantation system is provided.

In one aspect associated therewith, other ion source components, e.g., cathodes, repellers (corresponding to cathodes and filaments respectively), and the like, may be used to selectively etch or deposit materials thereon A suitable heating element for adjusting the surface temperature can be mounted.

In another embodiment, an indirectly heated cathode (IHC) ion source may include two cathodes (instead of cathodes and anti-cathodes). During implantation, one cathode may act as an anti-cathode, and during a repair or calibration process, the temperature of both cathodes may be controlled to deposit or etch the material as needed.

In another aspect, the present invention provides a process for the preparation of a composition comprising: (a) conditions for performing deposition of a substance on a filament, a cathode or other ion source component as described above; And (b) flowing a cleaning gas through the system under conditions selected from the group consisting of conditions for performing etching of the deposited material from a filament, cathode, or other ion source as described above. To a method of cleaning one or more components of the ion implantation system to at least partially remove ionization-related deposits from one or more components of the system.

Another aspect of the present invention is a method of forming a filament, comprising: contacting a filament of an ion source with a reagent effective to deposit or etch the material on the filament according to the temperature of the filament relative to the temperature of the arc chamber wall; And adjusting the temperature of the filament and the temperature in the arc chamber to effect deposition or etching of the material in the filament to maintain a predetermined electrical resistance. And how to maintain it. In general, material is deposited on the filament if the temperature of the filament is sufficiently high (e.g., greater than 2000 degrees Celsius), as long as the wall of the arc chamber is at a low or medium temperature (just below the temperature of the filament). Although the temperature of the arc chamber wall is preferably higher or lower than the temperature of the filament, regardless of the temperature of the arc chamber wall, the temperature of the filament is low or intermediate (for example, lower than about 1500 ° C to 2000 ° C) , Material etching from the filament occurs.

In another embodiment, the present invention provides a method for removing ionization-related deposits, comprising contacting an ion implantation system or one or more components thereof with BrF ₃ under conditions where BrF ₃ is chemically reactive with the deposit To a method of cleaning an ion implantation system or one or more components thereof to remove ionization-related deposits.

In another embodiment, the present invention provides an ionization-related deposit, comprising contacting a foreline of the ion implantation system with the cleaning gas under conditions wherein the cleaning gas is chemically reactive with the ionization- To a method for cleaning a foreline of an ion implantation system for removal thereof. The method can improve the performance of the ion implantation system and prolong the life span.

In another embodiment, the present invention is directed to a method of making a gas mixture comprising contacting a gas mixture comprising at least one scrubbing gas and at least one deposition gas with a cathode, wherein the gas mixture comprises depositing a material on the cathode, To a method for improving the performance and prolonging the life of an ion implantation system that balances the erosion of materials or other materials.

Other aspects, features, and embodiments of the present invention will become more fully apparent from the following specification and appended claims.

FIG. 1 is a graph of source life time data before and after introduction of a cleaning process in a home position, showing an increase in lifetime due to the above process.
2 is a graph showing the effect of XeF ₂ on the suppressor leakage current, as described in Example 1;
Figs. 3A and 3B are photographs showing evidence of the cleaning effect in the in-situ position, as described in Example 1. Fig.
Figs. 4A and 4B show the in-situ cleaning effect, as described above in Example 5. Fig.
5A and 5B are graphs showing the increase in the filament weight (FIG. 5A) and the filament current (FIG. 5B) over time with XeFe ₂ flow.
6 is, with respect to the tungsten in a transport system having a flow XeFe _2, a graph showing the filament weight change as a function of the filament current.
Figure 7 is a graph showing changes in the cathode bias power as a function of time and gas type.
Figure 8 is a graph showing the change in cathode W weight as a function of bias power.

The present invention relates to an apparatus and method for monitoring, controlling and cleaning a semiconductor process system and / or its components, and to the cleaning composition.

In one aspect, the present invention relates to the removal of deposits from a component of a semiconductor process system or a semiconductor process system, wherein the system or system component is contacted with a cleaning composition comprising a gas phase reactive material.

As used herein, the term "gas phase reactive material" refers to halide compounds and / or complexes in gas or vapor form, ionic and plasma forms of the compounds and / or complexes, and components and ions derived from the compounds, complexes and ions and plasma forms Quot; is intended to be interpreted broadly as a material comprising. In addition, the gas-phase reactive materials widely used in the practice of the present invention may be used in a wide variety of applications, including but not limited to, "gas phase reactive composition", "cleaning agent", "cleaning gas", "etching gas" Quot; cleaning agent ", "reactive halide "," cleaning compound ", "cleaning composition "," cleansing steam ", "etching steam" or any combination of these terms.

Quot; ion source region "as used herein in connection with an ion implanter includes but is not limited to a vacuum chamber, a source arc chamber, a source insulator, an extraction electrode, a suppression electrode, a high voltage insulator, a source bushing, a filament and a repeller and a repeller electrode. As will be understood by those skilled in the art, "ion source region" is used in its broadest sense. For example, a Bernas or Freeman ion source assembly includes a filament and a repeller electrode, and the IHC source assembly includes a cathode and an anti-cathode.

The present invention contemplates semiconductor processing systems and components thereof as well as other substrates and devices where deposits are susceptible to being formed on top of the process during normal processing operations. This practice includes, but is not limited to, cleaning of the vacuum foreline and the roughing pump. As will be appreciated by those skilled in the art in the description herein, the scrubbing gas may flow through a selected one of a plurality of ports to bypass a specific region of the injector and / or a specific region of the target. For example, XeF _2, or other purge gas, can be transported through the port adjacent to the region in which cleaning is required. The cleaning performance can be improved as long as most of the cleaning gas is directed to the target area and is lost by reaction with the residue along the flow path (e.g., if cleaning gas is introduced solely through the ion source chamber) , Can be improved. The selected port may already exist or be formed / formed for this purpose. This technique may be used to clean, but not limited to, the ion source region, the magnet / analyzer region, the vacuum system, the processing chamber, etc. of the implanter. The rinsing can be realized by continuously flowing the rinsing gas across and / or across the desired area of the injector for a predetermined period of time. Alternatively, or in conjunction therewith, a cleaning gas may be confined to the system for a predetermined period of time to allow the cleaning gas to diffuse and react with unwanted residues and / or deposits.

The present invention provides various embodiments of ion implantation systems having the ability to perform desirable filament growth or otherwise filament etching by properly controlling the temperature of the arc chamber to grow / etch the filaments in the ion source of the arc chamber.

A further aspect of the present invention is a process for cleaning component areas of an ion implanter or implanter under a plasma or high temperature condition in an in-situ or off-axis cleaning facility, wherein WF _x , AsF _x , PF _x and TaF _x , With a stoichiometrically appropriate value or an appropriate range of values).

Another further aspect of the invention relates to the use of BrF ₃ for cleaning the ion implantation system or components thereof in an in-situ or off-site facility under ambient temperature, high temperature or plasma conditions.

Due to the operation of the ion implantation system, ionization-related materials are deposited on the system and its components. The present invention contemplates a method for monitoring, controlling and / or cleaning an ion implantation system or one or more components thereof for at least partially removing the ionization-related deposits from the system and / or components thereof. The cleaning method includes contacting the cleaning composition comprising the gas phase reactive material with the system and / or components thereof under conditions that allow the vapor phase reactive material to react with the deposit to allow at least partial removal of the deposit do.

In addition to the ionization-related deposits inherently produced from the feedstock gas, the present inventors also confirm that deposits or residues formed in the ion implantation system may result from the reaction of the feedstock gas with the materials constituting the system components I could. For example, the vacuum chamber of the ion implantation system may be constructed using stainless steel or aluminum. The system components in the vacuum chamber may be selected from the group consisting of graphite (e.g., standard or amorphous), an insulating material (e.g., boron nitride), and / or a sealant material (e.g., Teflon TM, Kel- , PEEK (trademark), Delrin (trademark), Vespel (trademark), Viton (trademark), Buna-N, silicon, have. Other materials that may be present in the ion implantation system and prone to deposit-forming chemical reactions therein include, but are not limited to, epoxy, ceramic, lead oxide-containing epoxy compositions, aluminum nitride, aluminum oxide, silicon dioxide, Boron.

The ion source itself can be composed of tungsten, graphite, molybdenum or tantalum, sometimes with trace amounts of copper and silver. The ion source arc chamber is generally comprised of tungsten or molybdenum, or is constructed with a graphite body lined with tungsten or molybdenum. In this case, a fluoride source feed material such as BF ₃ , GeF ₄ , SiF ₄ , AsF ₅ , PF ₅ and / or PF _{3 can be used to} deposit the material of the arc chamber, such as tungsten or molybdenum, React at an operating temperature to form an intermediate by-product, and the resulting by-product may migrate to the system to deposit tungsten or molybdenum and liberate the fluorine.

For example, a feedstock gas such as GeF ₄ will dissociate in the ion source chamber, and the resulting glass fluoride will attack the material in the arc chamber, such as tungsten. This reaction will occur with the tungsten on the cooler surface so that when the plasma springs and the filament becomes hot, the fluoride will react with the wall tungsten in the arc chamber to corrode the wall and form WF ₆ gas. The WF ₆ will then deposit tungsten on the hot filament and grow its size.

While GeF ₄ produces a large amount of free fluorine, a feedstock gas, such as BF ₃ or SiF ₄ , produces a relatively small amount of free fluorine, thereby depositing a relatively low level of tungsten on the filament, But still significant).

A fluorine-free feedstock gas, such as PH ₃ and AsH ₃ , is also a problem because it deposits metal from the filament onto the wall of the arc chamber while thinning the filament.

Thus, the present invention contemplates cleaning of the ion implantation system or components thereof for at least partial removal of the same ionization-related deposit as the material of the arc chamber.

The cleaning according to the present invention can be carried out in an ion implantation system in which various feedstock gases are simultaneously introduced into the system. The feedstock gas may also be used in conjunction with one or more gaseous reactive materials, or alternatively may be introduced into the system in alternation with one or more gaseous reactive materials.

The ionization-related deposits associated with the cleaning method of the present invention include various materials that can interfere with the normal operation of the ion implantation system, for example, by being formed and deposited in the ion source or other ionization processing apparatus. The deposited material may comprise, consist essentially of, or consist essentially of, silicon, boron, phosphorus, germanium, arsenic, tungsten, molybdenum, selenium, antimony, indium, carbon, aluminum and / have.

The ionization-related deposits deposited on the ion source arc chamber and the extraction electrode can form flakes and small particles. Once formed, these particles can be transported into the ion beam, e.g., a beam of dopant ions implanted into the wafer. Once the transported particles reach the wafer, the particle contamination created on the wafer can significantly reduce the yield of useful devices fabricated on the wafer. The cleaning method of the present invention removes the ionization-related deposits before the ionization-related deposits form flakes and particles, thereby reducing particles on the wafer and increasing the yield of semiconductor devices.

The gaseous reactive material or cleaning gas used in the cleaning in accordance with the present invention may comprise any material effective to at least partially remove the ionization-related deposits in the ion implantation system.

The present invention also contemplates the use of a gas-reactive material to remove ionization-related deposits from undesirable locations and / or deposit materials at desired locations by appropriate control of the reaction. In certain embodiments of the present invention, tungsten constitutes the material to be removed as an undesirable deposit, and in another embodiment, tungsten is preferably deposited on a surface where its presence is beneficial. Thus, the _{XeF 2, GeF 4, SiF 4} , BF 3, AsF 5, AsF 3, PF 5 , and / or PF ₃ and the tungsten fluoride intermediates are reactive gas control method, and cleaning of the present invention enough to form such Can be used. In addition, tungsten fluoride, such as WF ₆ , WF ₅ and / or WF ₄ , can be used directly in the control and cleaning methods of the present invention. In this manner, a vapor-phase reactive substance of the present invention is _{non-limited, XeF 2, GeF 4, SiF} 4, BF 3, AsF 5, AsF 3, PF 5, PF 3, F 2, TaF 3, TaF 5, WF ₆ , WF ₅ and / or WF ₄ .

In various specific embodiments, the gaseous reactive material is administered with a "cleaning enhancer" or "co-reactant" that will enhance the volatility of the gaseous reactive material, Resulting in the removal of more deposits than ever. For example, removal of iridium deposits by XeF ₂ can be enhanced by co-administration of a Lewis base and an electron-back-bonding species. In certain embodiments, carbon monoxide, trifluorophosphine, and trialkylphosphine may be used.

As a further example, in an ion implantation system in which a plasma ionized feed gas is stored in an arc chamber having a filament on one side and a repeller on the other side and a tungsten wall separated by a ceramic insulator, The components of the chamber may be contaminated by the feed gas, components of the arc chamber, and decomposition products of carbon.

In this situation, the volatile fluorides, such as a useful cleaning agent for the removal of metal contaminants, such, the tungsten forming the XeF ₂ is an effective oxygen in removing contaminant of carbon by conversion of carbon to CO, CO ₂ and / or COF ₂ - containing Can be combined with additives. In certain embodiments of the invention, useful for the purpose of oxygen-containing additive components include, but are not limited to, including NO, N ₂ O, NO _2, CO ₂ and / or O _2.

Accordingly, the present invention includes both a detergent effective to remove metal contaminants by reaction to form volatile (gaseous) fluoride compounds of the metal, and a detergent effective to remove carbon contaminants by forming volatile oxides or oxyfluorides Are considered. These cleaning reagents can flow simultaneously or sequentially into the arc chamber.

In one embodiment, the reagent flows simultaneously into the arc chamber under ionizing conditions to cause the detergent to ionize both to convert metal and carbon contaminants into volatile compounds that are easily removed from the chamber by mechanical pumping.

Conditions enabling the reaction of the gas-phase reactive material and the deposit may include any suitable conditions such as temperature, pressure, flow rate, composition, etc., and under such conditions, the gas-phase reactive material may be injected into the substrate, These materials are contacted and chemically interacted with the contaminants to be removed from the surface of the equipment.

Examples of the various conditions that can be used include, but are not limited to, ambient temperature, temperatures in excess of ambient temperature, presence of plasma, absence of plasma, subatmospheric pressure, atmospheric pressure and atmospheric pressure.

In various embodiments, the specific temperature for contacting the gas phase reactant to remove deposits may range from about 0 to about 2000 < 0 > C. The contacting step may involve the delivery of a vapor-phase reactive material that is a carrier gas, or in pure form, or that is mixed with additional detergents, dopants, and the like. The gaseous reactive material may be heated for chemical reaction with the deposit at room temperature to increase the kinetic of the reaction.

The reaction between the gaseous reactive material and the contaminant deposit can be monitored and / or controlled based on various characteristics of the reaction between the detergent and the contaminant. Such response characteristics may include pressure, time, temperature, concentration, presence of a particular species, rate of pressure change, rate of concentration change (of a particular species), change in current, and the like. Thus, the introduction of a gaseous reactive material into the system may be accomplished by the presence of a predetermined characteristic of the reaction, such as a predetermined pressure in the vacuum chamber, a predetermined amount of time, or a predetermined temperature, the concentration of a particular element in the system, Or other species, or the acquisition of the realization of the predetermined current condition in the monitoring operation.

The tungsten deposit can be generated from the reaction of the feed gas with the arc chamber of the injector system. The method used to clean the deposits may vary depending on the temperature gradient of the system, and / or the current flow through the filaments and through the filaments, and / or any other feature that may be usefully measured and monitored.

For example, fluorine from a feed material can react with an arc chamber at a first temperature to form WF ₆ by the following reaction (1) or (2):

3F ₂ (g) + W (s) -> WF ₆ (g) (1)

6F (g) + W (s) - > WF ₆ (g) (2)

The following reaction may also be present between the tungsten material of the arc chamber and the cleaning gas:

3XeF ₂ + W - > WF ₆ (3)

Alternatively, WF ₆ (or WF ₅ or WF ₄ ) may be provided directly to the system.

The tungsten fluoride, once formed or otherwise present in the system, can then be moved to another location in the system. Depending on the temperature at these other locations, tungsten fluoride etches or deposits tungsten at that location. In a filament, the temperature varies mainly depending on the actual current flux through it. The temperature at other locations within the arc chamber may vary depending on the specific location and design of the arc chamber, the filament current, and other non-filament currents.

When the second location is high temperature, the tungsten fluoride is decomposed, tungsten is deposited, and fluorine is released, so long as tungsten fluoride is still present, the size of the tungsten deposit grows. The deposition reaction may comprise the following reactions (4), (5) and / or (6):

WF ₆ -> W + 3F ₂ (4)

2WF ₅ -> 2W + 5F ₂ (5)

WF ₄ - > W + 2F ₂ (6)

On the other hand, if the second location is at a moderate temperature, tungsten fluoride can remove tungsten and etch locations holding fluorine within the reaction product so that the etched locations are reduced as an etch sequence. Such an etching reaction may include the following reactions (7), (8) and / or (9):

WF ₆ (g) + 2W (s) - > 3WF ₂ (g) (7)

2WF ₆ (g) + W (s) - > 3WF ₄ (g) (8)

5WF ₆ (g) + W (s) - > 6WF ₅ (g) (9)

Thus, in order to remove the tungsten deposit, the temperature of the component having the deposit may be selected to maximize the removal rate and removal range.

In another embodiment of the present invention, the boron and / or molybdenum deposits in the arc chamber are removed in a corresponding manner.

The contact of the process equipment and the cleaning agent in the method of the present invention can be performed while monitoring the pressure change during contact, and the contact is terminated when the pressure change reaches zero.

Alternatively, the contact may be carried out while monitoring the gaseous reactive material, or a reactant derived therefrom, or a partial pressure of the reaction product produced during contact, and the contact is terminated when the partial pressure reaches a predetermined value, i. Such endpoint monitoring may be achieved, for example, by a suitable endpoint monitor, for example, as described in more detail in U.S. Patent No. 6,534,007 and U.S. Patent Applications 10 / 273,036, 10 / 784,606, 10 / 784,750 and 10 / 758,825 Type endpoint monitor, or a thermopile infrared (TPIR) or other infrared detector.

In another embodiment, the contacting may be carried out by controlled flow of the gas-phase reactive material using components of the process equipment system to enable control of the partial pressure of the gaseous reactive material and hence control of the reaction rate.

In another embodiment, a continuous flow of gas-reactive material at a predetermined flow rate is used to perform the cleaning operation.

As discussed above with respect to reactions (1) - (9), the ionization-related deposits of tungsten can be deposited at very high temperatures and etched at low or moderate temperatures. In this regard, ion-related deposition refers to deposition formed by plasma operation, not necessarily due to ions. Thus, the deposition of tungsten can be carried out under a plasma element (for example, no ions), as long as a sufficiently high temperature surface is present. If the location of the deposition or etch is a filament in the injector system, the temperature and current fluxes are directly related to each other. When the filaments are etched, the filaments become thinner and the resistance to current increases as the cross-section of the filaments decreases, thereby reducing the current flow through the filaments. If the conditions in the filament promote deposition on the filament, as the cross-section of the filament increases and the filament becomes thicker, the resistance to the current decreases with successive deposition, correspondingly the current flow through the filament increases do.

In another aspect, the present invention is directed to a method for monitoring the deposition of a source filament, and thus the growth of a filament, including monitoring the current flow through the filament. As the filament cross section increases due to deposition, the resistance to the current decreases and the current increases to maintain the filament at the temperature required to support the plasma in the arc chamber. Thus, an increase in the monitored current can be used to indicate the need for filament cleaning.

In a further aspect, the invention relates to a method of monitoring the etching or cleaning of filaments by monitoring the current flow through the filaments. As the filament cross section decreases due to etching, sputtering or evaporation, the resistance to the current increases and the current decreases to maintain the filament at the temperature required to support the plasma in the arc chamber. Thus, a monitored reduction of this current can be used to indicate the need for deposition of additional material on the etched filament, or for termination of the cleaning or ionization process.

Another means of the present invention includes a method of controlling the condition of a filament, based on monitoring the current flowing through the filament as described above.

In one embodiment, the gaseous reactive material is flowed into the system, for example by igniting the plasma or otherwise blocking the plasma, while still maintaining the filament at a high temperature (e.g., about 2000 ° C) Corresponding to causing deposition (e.g., tungsten from the arc chamber walls), a reduction in the monitored filament current provides an indication that the filament is nearly destroyed. This reaction can be continued until there is a current in the predetermined range for effective operation of the ion implantation system, indicating that the filament has been "regrowth" to a satisfactory degree.

In another embodiment, the increase in monitored filament currents provides an indication that the filament has grown due to material deposition. Correspondingly, the filament is allowed to cool for a predetermined period of time, or to a predetermined temperature (for example, it may range from room temperature to about 2000 ° C), to sufficiently cool the filament to enable etching of the filament, The reactive material flows into the system. The subsequent etching reaction mediated by the gas-phase reactive material can then proceed until there is a current within a predetermined range for effective operation of the ion implantation system, indicating that the filament has thinned to an appropriate level.

Thus, the method of the present invention comprises contacting a substrate with a gas-phase reactive material for a time sufficient to at least partially remove the deposit from the substrate, thereby forming at least one of boron, silicon, arsenic, phosphorus, germanium, tungsten, molybdenum, selenium, Including indium, tantalum, and carbon, from the substrate. Gas phase reactive material for this purpose is at least one _{XeF 2, XeF 4, XeF 6} , GeF 4, SiF 4, BF 3, AsF 5, AsF 3, PF 5, PF 3, F 2, TaF 3, TaF 5, WF _{6, WF 5, WF 4,} NF 3, IF 5, IF 7, KrF 2, SF 6, C 2 F 6, CF 4, Cl 2, HCl, ClF 3, ClO 2, N 2 F 4, N 2 F _{2, N 3 F, NFH 2} , NH 2 F, HOBr, Br 2, BrF 3, C 3 F 8, C 4 F 8, C 5 F 8, CHF 3, CH 2 F 2, CH 3 F, COF 2 _{, HF, C 2 HF 5,} C 2 H 2 F 4, C 2 H 3 F 3, C 2 H 4 F 2, C 2 H 5 F, C 3 F 6, COCl 2, CCl 4, CHCl 3, CH ₂ Cl ₂ and CH ₃ Cl.

The fluorinated zenon compound may be used as a cleaning agent and as a plasma source reagent in the practice of the present invention and may comprise any suitable number of fluorine atoms. A higher proportion of F for Xe can be cleaned faster and more efficiently relative to lower F / Xe compounds. Higher vapor pressures increase the delivery rate of the detergent and allow delivery of more material.

In one embodiment of the invention, xenon hexafluoride is used as a detergent or as a plasma source reagent. Although the vapor pressure of XeF ₆ at room temperature is about seven times higher than the vapor pressure of XeF ₂ , XeF ₆ and XeF ₄ are highly reactive with water. XeF ₆ is most advantageously used in a cleaning environment that does not involve the presence or production of water, hydrocarbons, hydrogen or reducing agents. However, when a cleaning compound having a lower vapor pressure is used, adjustment to the flow circuit may be required to avoid excessive pressure drop in the flow path and to maintain a suitably high delivery rate of the cleaning agent.

The apparatus for carrying out the method of the present invention may be constructed and arranged in any suitable manner to provide cleaning using gas-phase reactive materials.

In one embodiment, the present invention provides an ion implantation system comprising (i) an ion implantation system comprising one or more components for accumulating ionization-related deposits during an ion implantation process in the system, (ii) a gas phase reactive material, A cleaning composition comprising a cleaning composition comprising a cleaning composition comprising a halide compound that is reactive with the deposit under cleaning conditions, including contact of the deposit, and at least partially removes the deposit from the at least one component; (iii) A flow circuit adapted to deliver the cleaning composition from the at least one component to the at least one component for contacting the cleaning composition under the cleaning condition; and (iv) a flow circuit adapted to at least partially remove the deposit from the at least one component A flow component adapted to control flow It provides an ion implantation and a cleaning assembly including.

The flow components in the assembly may be of any suitable type including, for example, valves, valve actuators, flow restrictors, regulators, pumps, mass flow controllers, pressure gauges, residual gas analyzers, central processing units, These flow components are suitably adapted to operate under the particular cleaning conditions used.

One or more components in an implant device that accommodate ionization-related deposits during ion implant processing in a system may be of any suitable type, such as a vacuum chamber, an arc chamber, an electrode, a filament, a high voltage bushing, a magnetic waveguide, Clamp rings, wheels, discs, and the like. In one embodiment, the component is a vacuum chamber or a component contained therein.

The cleaning composition source may include a material storage and dispensing package containing a cleaning composition. The material storage and dispensing package includes, for example, a container that may be generally cylindrical to define its internal volume. In certain embodiments, the cleaning composition may be a solid at ambient temperature conditions, and such a cleaning composition may be supported on the increased surface area in the vessel. Such increased surface area may include a structure therein, for example a tray as described in U.S. Patent No. 6,921,062, or it may comprise a porous inert foam, such as, for example, anodized aluminum, stainless steel, nickel, It is possible to provide a constant rate of evaporation of the cleaning material to provide sufficient vapor pressure for the distribution and ionization steps of the associated cleaning process. When a tray is used, the cleaning composition may be supported on the surface of a tray having a flow-through conduit connected thereto to allow vapor in the vessel to flow upwardly toward the dispensing outlet of the vessel in a dispensing operation.

In the device arrangement, the flow circuit is adapted to transport the cleaning composition from the cleaning composition source to the arc chamber under cleaning conditions. Such adaptation may be based on various properties of the cleaning composition. For example, if the cleaning composition has a low vapor pressure, high conductivity can be utilized to avoid unnecessary pressure drop in the flow path. Methods of maximizing flow conduction and minimizing flow shrinkage are well known in the art.

In all the cleaning methods of the present invention, cleaning can optionally be used with additional methods and apparatus for extending the life of an ion implantation system, particularly an ion source. This lifetime extension method may include modifying the ion implantation system to accommodate a particular substrate, deposited material and / or gaseous reactive material. System device modification includes providing an extraction electrode with an active thermal conditioning system, providing an actively heated extraction electrode that reduces the frequency / generation of electrical emission, a metal, preferably aluminum, molybdenum or alumina (Al ₂ O ₃ ) Providing a remote plasma source, connecting the extraction electrode and the heater, connecting the extraction electrode and the cooling device, providing a smooth and unextracted extraction electrode, separating the chamber outlet and the reactive gas by ionisation A plasma chamber arranged to receive a source gas capable of generating a flow of reactive gas through a conduit for transporting the reactive gas to the chamber, a plasma chamber configured to detect a substantial termination of the exothermic reaction of the reactive gas with the contaminant on the surface in the processing system Providing a temperature detector, a process chamber sensitive to the harmful effects of gas-phase reactive substances (E. G., Providing a shield against the gaseous reactive material around a component sensitive to a gaseous reactive material) and / or the use of system components comprising aluminum or alumina .

Methods of prolonging the lifetime of the process apparatus include actively heating the extraction electrode to reduce the frequency and occurrence of the electrical discharge, heating the extraction electrode above the condensation temperature of the source material delivered to the ion source, Actively controlling the temperature of the extraction electrode adapted to the specific type of source (e.g., heating or cooling the electrode with a heated or cooled ion source), and / or during extraction Lt; RTI ID = 0.0 > elevated. &Lt; / RTI > These additional device variations and methods are described in more detail in U.S. Patent Application Publication Nos. 2006/0272776 and 2006/0272775, and International Patent Application Publication No. WO 05/059942, which are hereby incorporated by reference in their entirety.

In certain embodiments, the ion implantation system comprises an arc chamber and a dopant source, wherein the dopant source is selected from the group consisting of BF ₃ , XeF ₂ , AsH ₃ , PH ₃ , GeF ₄ , SiF ₄ , H ₂ Se, AsF ₅ , AsF ₃ , PF ₅ , PF ₃ or other boron, silicon, arsenic, phosphorus or germanium-containing dopant sources.

In another implantation, the present invention relates to an ion implantation method comprising generating a plasma from a dopant source gas flowing through an arc chamber in an arc chamber of an ion implantation system to form dopant source ions for implantation Wherein at least a portion of the time the dopant source gas flows through the arc chamber, the gaseous reactive material flows through the arc chamber simultaneously with the dopant source gas to perform cleaning in the ion implantation system.

In general, simultaneous flow of dopant source gas and gaseous reactive material may be performed to achieve in-situ cleaning, but it is typically desirable to perform a cleaning operation in a sequential manner, for example, When the ion source generates a second plasma from a second dopant source after generating the first plasma from the first dopant source, the gaseous reactive material is in the middle of flowing through the ion source, with or without generating plasma Use a cleaning step.

In one embodiment, the present invention provides a method of forming a doped silicon substrate comprising implanting Xe ⁺ ions into a silicon substrate and implanting dopant ions into the silicon substrate. In this way, implantation of Xe ⁺ ions contributes to making the crystal structure of the substrate amorphous.

Fluorinated xenon plasma, for example, when generating a XeF ₂ plasma, for cleaning, Xe ⁺ ions may be some low energy sputtering (sputter) cleaning of the source itself. After extraction, the Xe ⁺ ions may undergo some high energy sputtering of components located downstream of the ion source, such as vacuum walls, ion optics components, wafer disks, and wafer holders.

Similarly, when using tungsten fluoride species such as WF ₆ , WFs, and / or WF ₄ , the free fluoride can sputter clean various components of the ion source and / or tungsten can be used to deposit various components of the ion source / RTI > The action that takes place between the cleaning and deposition steps depends on the temperature of the individual components of the system.

In various aspects, the present invention is directed to a method and apparatus for cleaning the ion source region of an ion implantation system used in the fabrication of microelectronic devices. The ion source region may include, for example, an indirectly heated cathode source, a Freeman source, or a Bernas source.

In one embodiment, the present invention provides a process for preparing a vacuum chamber and / or a component therefrom for a sufficient time under conditions sufficient to at least partially remove the residue from the vacuum chamber of the ion implanter and / Removing the residues from the vacuum chamber and components in situ by contacting; And the gas-phase reactive material selectively reacts with the residue and at least reacts with the material constituting the vacuum chamber and / or component of the ion implanter, when the residue and the residue are different from the material constituting the vacuum chamber and / or the component (E. G., Substantially nonreacting, preferably not completely reacting), and when the residue is the same as the material making up the vacuum chamber and / or the component, To the removal of residues from the vacuum chamber and components in situ in a manner that allows them to react with both the vacuum chamber and / or the component.

As used herein, the term "selectively " applied to the reactivity of a gas-phase reactive halide with a residue is used to describe the preferential reaction between the gas-phase reactive halide and the residue. When the vapor-phase reactive halide remains essentially unreactive with the vacuum chamber of the ion implanter and / or the constituent material of the component, and the ion implanter vacuum chamber and / or component comprises the same or similar elements as the elements of the residue itself May react to some extent with the materials that make up the vacuum chamber and / or component. For example, the gaseous reactive material may exhibit selective reactivity and also react with tungsten within the component itself, while removing tungsten deposits from the component. In order for this co-reaction to take place, the residues and components need not be exactly the same material, but will include some substances in common.

In another embodiment, the components of the ion implanter are cleaned out of the way in a separate, dedicated chamber from which the component is removed from the ion implanter.

More specifically, this cleaning depends on the following three factors: the reactivity of the cleaning precursor, the volatility of the cleaning reaction byproduct, and the reaction conditions used in the chemical cleaning. The cleaning composition must remove unwanted residues while minimizing wear of the materials making up the implanter. The byproducts generated by the cleaning reaction should exhibit sufficient volatility to facilitate its removal by the vacuum system of the ion implanter or other pumping device.

Cleaning of residues formed from the same material as the components of the injector somewhat wears the component itself. In particular, the use of XeF ₂ as a detergent to remove tungsten deposits from a system utilizing a tungsten arc chamber will remove some of the tungsten from the interior of the arc chamber. However, in terms of maximizing system efficiency, some loss of internal material in the arc chamber is not significant in view of system performance, which is reduced when the system is not cleaned and tungsten deposits accumulate in the system.

Gas phase reactive material may comprise, for example, a fluorinated xenon compound vapor, for example, XeF ₂ vapor. XeF ₂ is the preferred reactive halide gas and will sublimate at room temperature, but may be heated using a heater to increase the rate of sublimation. XeF ₂ is known to be an effective silicon etchant and is being used as a silicon selective etchant in microelectromechanical system (MEMS) device processing. Specifically, XeF ₂ reacts with silicon according to the following reaction:

2 XeF ₂ (g) + Si (s)? 2 Xe (g) + SiF ₄ (g)

The silicon / XeF ₂ reaction can take place without activation, i.e., without plasma or thermal heating. The reaction rate of XeF ₂ with silicon is much higher than the reaction rate between XeF ₂ and SiO ₂ , so XeF ₂ shows selectivity for the reaction with silicon.

XeF ₂ or other fluorinated xenon compound is useful as an etchant of the metallic boron in the practice of the invention. Without wishing to be bound by theory, it is believed that boron is etched according to the following reaction:

_{3XeF 2 (g) + 2B (} s) → 3Xe (g) + 2BF 3 (g) (11)

The use of XeF ₂ as an etchant for arsenic, phosphorus and germanium is contemplated by the present invention and may involve the following reactions:

_{5XeF 2 (g) + 2As (} s) -> 5Xe (g) + 2AsF 5 (g) (12)

5XeF ₂ (g) + 2P (s)? 5Xe (g) + 2PF ₅ (g)

2XeF ₂ (g) + Ge (s)? 2Xe (g) + GeF ₄ (g)

This reaction can be performed with or without energy activation.

The method and apparatus of the present invention can be used to remove residues at least partially from components of an ion implanter, for example, removing at least 25% of the residue, more preferably at least 50% of the residue, most preferably at least 75% And the residues are selectively removed for these materials when the residues are different from the materials that make up the components of the implanter, such as aluminum, tungsten, molybdenum, graphite, insulating materials, Thereby at least partially removing the residue from the components of the implanter.

If the residue of the structure and the component material are the same material, a similar level of residue removal is desirable, while maintaining the removal of material from the component to a low level, e.g., in the micron or tens of microns range, without significantly impacting the performance of the component . In addition, since deposits in general do not have a uniform thickness or deposition, they may be more reactive than the material of the component itself in the cleaning process, and thus the gaseous reactive material composition may react with the residues .

Several modes of delivery to the ion source region for in-situ cleaning of the gas-phase reactive composition, including stagnant, continuous, and direct introduction, can be used. Such a cleaning scheme is described in more detail in International Patent Application Publication No. WO 07/127865, along with apparatus and methodology usefully employed in the practice of the present invention. The content of International Patent Application Publication No. WO 07/127865 is incorporated herein by reference in its entirety. Although the use of XeF ₂ as a cleaning composition is described herein in connection with various embodiments of the present invention, it is contemplated that other fluorinated compounds such as WF ₆ , WF ₅ and / or WF ₄ may be used in conjunction with XeF ₂ , Or other and further fluorinated compounds may be used. For example, BrF ₃ can be used to etch tungsten without a plasma. In another aspect, the present invention is directed to a method of improving the performance and prolonging the lifetime of an ion implantation system using a solid doping material comprising using XeF ₂ or N ₂ F ₄ as a carrier gas for solid doping materials. Solid doping material is, but not limited This allows, a non-small element, the element, selenium element, antimony element, SbF _3, InCl, SeO _2, Sb ₂ O ₃ and InCl _3. As contemplated by the present invention, the use of XeF ₂ or N ₂ F ₄ as carrier gas for Sb ₂ O ₃ , InCl _3, or other solid doping materials is dependent on the presence of Sb, In, and other Remove the dopant. The method has utility even when a switchover to boron occurs after Sb implantation. Advantages achieved by the method of the present invention are more than two: firstly, it is possible to provide real-time source cleaning to prevent or reduce dopant accumulation on the ion source chamber and its components, thereby prolonging the life of the ion source Together, the ion source performance is improved; Second, the plasma and / or beam current is improved and / or stabilized.

In another aspect, the present invention relates to a method of improving the performance and prolonging the lifetime of an ion implantation system using a gas doping material, including using XeF ₂ or N ₂ F ₄ as a co-flow gas with a gas doping material will be. The gas doping material is GeH ₄ And it comprises a BF _3, but is not limited to this. As contemplated by the present invention, the use of XeF ₂ or N ₂ F ₄ as a co-flow gas with GeH ₄ or other gas doping materials removes Ge or other dopants deposited on the source chamber and its components . Advantages achieved by the practice of the present invention are more than twofold: firstly, it is possible to provide real time source cleaning to prevent or reduce dopant accumulation on the ion source chamber and its components, thereby improving ion source performance , Extending ion source life; Second, the plasma and / or beam current is improved and / or stabilized.

In another aspect, the present invention is directed to a method and system for cleaning a foreline of an ion implantation system, comprising contacting a foreline of an ion implantation system with a cleaning gas under conditions that the cleaning gas chemically reacts with the deposit and at least partially achieves deposit removal. To remove ionization-related deposits from the ion implantation system. The deposits include, but are not limited to, B, Ge, Si, P and As, or mixtures thereof. Cleaning gas is _{XeF 2, N 2 F 4,} F 2 , and includes deposits and other reactive fluorinated species, such as the components, but it is not limited thereto. As will be appreciated by those skilled in the art, the amount of cleaning gas required will depend on the amount of deposit present. Similarly, the amount of heat released during the reaction of the scrubbing gas and the deposit depends on the flow rate of the scrubbing gas. The identification and concentration of the byproduct species resulting from the cleaning process depends on the cleaning gas flow rate, the composition of the deposit, and the pump purge flow rate. For non-limiting, illustrative purposes only, an example of using XeF ₂ to clean phosphorus from the foreline is described below:

The chemical reaction used to determine the amount of XeF ₂ required for the cleaning process is: 5XeF ₂ (g) + 2P (s) 5Xe (g) + 2PF ₅ (g). Formation enthalpy (kJ / mol) was listed herein in order to determine the heat liberated during the taking, the reaction from the literature [Lange's Handbook of Chemistry (14 th ed)]: XeF 2 (-164); Xe (O); P (0); And PF ₅ (-1594.4). The flow rate of XeF ₂ determines the time required for the cleaning process and the heat liberated. Without the means for heating the XeF ₂ cylinder, the maximum sustained flow rate is approximately 50 sccm, which is assumed to be an appropriate transfer tubing conductance. This flow rate can be increased to more than 100 sccm when the cylinder is maintained at room temperature by using a heating jacket. The amount of XeF ₂ required to clean the phosphorus deposits is shown in Table 1 below and the amount of heat released during the cleaning reaction is shown in Table 2 below.

Mass of phosphorus deposit (g) Mass of required XeF ₂ (g) 10 137 100 1367 1000 13,666

The flow rate of XeF ₂ (sccm) Heat Generation Rate (Watts) 50 17.6 100 35 200 70

The maximum production rates of the various by-products from the cleaning reactions described above are shown in Table 3 below.

The flow rate of XeF ₂ (sccm) AsF ₃ PF ₃ BF ₃ GeF ₄ SiF ₄ 50 0.20 g / min
(33.3 sccm) 0.13 g / min
(33.3 sccm) 0.10 g / min
(33.3 sccm) 0.17 g / min
(25 sccm) 0.12 g / min
(25 sccm)

As can be appreciated by those skilled in the art, the composition of the residues can vary, so the data shown in Table 3 indicates that the amount of by-products is determined for each element assuming that each element is a 100% Assumption is based on. Moreover, the maximum concentration of these species depends on the dilution flow rate in the exhaust system. For example, immediately downstream of the roughing pump, if the pump has a nitrogen purge of 10 slpm, the maximum steady-state concentration of PF ₃ is 3330 ppm. These values can be increased if the flow rate of XeF ₂ is higher than 50 sccm.

In one embodiment of the method described above, the cleaning gas flows into the injection source chamber, wherein the turbo pump is turned off, but the roughing pump is turned on. This practice improves the flow rate of the cleaning gas to the foreline deposits, thereby providing a faster cleaning process. Additionally, the scrubbing gas flow rate can be further improved by heating the gas cylinder, wherein the scrubbing gas is stored at or above room temperature. Preferably, in this embodiment, the transfer line from the gas cylinder to the ion implanter is similarly heated.

In another embodiment of the method described above, the cleaning gas flows into the injection source chamber in a pulse flow that is pumped to a low pressure after being filled to a specific pressure in the injection source chamber, pump and foreline. This process is repeated until the deposits on the foreline of the ion implantation system are removed. This embodiment preferably uses a isolation valve on the inlet of the roughing pump.

In a preferred embodiment, the embodiment described above further comprises heating the gas cylinder, wherein the cleaning gas is stored at room temperature or higher.

In all embodiments, the method preferably further includes a scrubber at the exit of the roughing pump to remove volatile byproducts from the cleaning process.

Each embodiment preferably further comprises an Xe recovery system, commercially available from Air Products and Chemicals, Inc. of Pennsylvania, USA, /www.fabtech. org / product_briefings / _a / new_product_air_products_offers_on_site_xenon_recovery.], which is incorporated herein by reference.

Another embodiment of a method for cleaning a foreline of an ion implantation system comprises providing a cleaning gas downstream of the turbo pump and continuously flowing the cleaning gas into the foreline of the ion implantation system. The continuous flow of the scrubbing gas may be directed directly to the source housing, the area between the source housing and the source turbo pump, and the source turbo pump downstream. This embodiment preferably also cleans the deposits on the foreline even when the implantation process is performed, thereby reducing the interruption in the operation of the ion implantation.

In the embodiments described above, the cleaning gas is preferably stored in a gaseous cylinder, and the method preferably further comprises heating the gaseous cylinder, wherein the cleaning gas is stored at or above room temperature.

The embodiment described above preferably further comprises providing a scrubber at the roughing pump outlet to remove volatile byproducts from the scrubbing process.

The embodiments described above further include providing an Xe recovery system commercially available from Air Products and Chemicals, Inc. (Pennsylvania, USA), which is available on the Internet site [http://www.fabtech.org/product_briefings/ _a / new_product_ air_products_offers_on_site_xenon_recovery.], which is incorporated herein by reference.

In another aspect, the invention is directed to a method of improving the performance and prolonging the lifetime of an ion implantation system having a cathode, comprising contacting the cathode with a gas mixture comprising at least one cleaning gas and at least one deposition gas , Wherein the gas mixture balances the deposition of material on the cathode and the removal of such material or other material from the cathode. The scrubbing gas of the gas mixture removes the dopant material deposited on the material of the cathode and cathode, but the deposition gas of the gas mixture directly or indirectly causes deposition of the dopant onto the cathode. This gas mixture maintains a balance between the accumulation of the dopant material and the removal of this or other material on the cathode, thus extending the life of the ion source. It will be appreciated that not only the dopant material may be deposited or etched, but also the material of the arc chamber walls, e.g., W or Mo, may be deposited or etched. The cleaning gas either prevents deposition directly (through sputtering or chemical etching) or indirectly (through chemical gettering of tungsten / molybdenum fluoride) or reduces the rate of deposition. The deposition gas can be supplied either through a halogen cycle (where fluorine from the gas etches W or Mo from the cooler wall and then decomposes W or Mo to a very hot cathode), or actually deposits dopant molecules / atoms on the cathode (For example, from BF ₃ to B) to cause deposition on the cathode and apply a similar mechanism to the filaments of the source of the vanasium ion. In the case of dopant deposition on an insulator or other sensitive components of the arc chamber, the cleaning gas tends to chemically etch the formed dopant deposit or may be deposited prior to dopant deposition in the first location to inhibit or minimize deposition, The cleaning gas can be reacted with the deposition gas. In the first case, for example, in that the cleaning gas can do inhibit the deposition, the deposition gas of GeH ₄ may be present in the Ge deposits onto the cathode, insulator or other components. If the cleaning gas is XeF _2, which can be reacted with GeH ₄ forms at least a GeF ₂ and / or GeF ₄ of the partial amount, these are significantly more volatile than Ge, and can be removed from the source region through the pump. Additionally, one or both of the deposition gas and the cleaning gas may be a dopant gas. Storage and dispensing of the gas mixture into the ion source injector is referred to as a safe delivery source (SDS) as described in U.S. Patent No. 5,518,528, incorporated herein by reference; A fluid storage and dispensing system (referred to as a Vacuum Actuated Cylinder (VAC)) comprising a tube holding a fluid at the desired pressure as described in U.S. Patent No. 6,101,816, incorporated herein by reference; Or by using a hybrid fluid storage and dispensing system of SDS and VAC (referred to as VAC-Sorb) as described in U.S. Patent No. 6,089,027, which is incorporated herein by reference. Such fluid storage and dispensing systems are more stable and more efficient than high pressure fluid storage and dispensing systems by providing sub-atmospheric pressure delivery of the gas. In addition, some of the gases of the gas mixture (which are incompatible to be co-present under high pressure fluid storage and dispensing systems) can be stored and dispensed together under the SDS, VAC or VAC-sorb system.

In one embodiment of the method described above, the gas mixture of gases is flowing simultaneously to contact the cathode or other sensitive components susceptible to deposition.

In another embodiment of the method described above, the gas of the gas mixture flows sequentially to contact the cathode or other sensitive component that is susceptible to deposition.

In another embodiment of the above described method, the gas mixture comprises a combination of at least one hydrogen-containing gas and at least one fluorine-containing gas, wherein the hydrogen-containing gas acts as a scrubbing gas, and the fluorine- It acts as a gas.

In another embodiment of the disclosed method, the gas mixture comprises a combination of one or more non-dopant gases, a gas that does not contain As, P, Ge, B, Si, or C, and one or more dopant gases, Wherein the non-dopant gas acts as a cleaning gas and the dopant gas acts as a deposition gas.

Examples of the cleaning gas but _{Xe / H 2, Ar / H} 2, Ne / H 2, Xe / NH 3, Ar / NH 3, Ne / NH 3, Ar / Xe , and Ar / Xe / H _2, not limited to .

Examples of deposition gases include, but are not limited to, F ₂ , N ₂ F ₄ , ClF ₃ , WF ₆ , MoF ₆ and NF ₃ .

Examples of the gas mixture is _{AsH 3 / AsF 3, AsH 3} / AsF 5, PH 3 / PF 3, PH 3 / PF 5, SiH 4 / SiF 4, H 2 / Xe / SiF 4, GeH 4 / GeF 4, H _{2 / Xe / GeF 4, H} 2 / GeF 4, B 2 H 6 / BF 3, H 2 / BF 3, F 2 / BF 3, CO 2 / F 2, CO 2 / CF 4, CO / F 2, CO / CF ₄ , COF ₂ / F ₂ , COF ₂ / CH ₄ , COF ₂ / H ₂ .

The features and advantages of the present invention are more fully illustrated by the following non-limiting examples.

Example One

This example illustrates the improvement in ion source lifetime and injector utilization achieved by using a chemical detergent to remove deposits. Preferably, the deposits are removed at regular intervals to prevent accumulation of contaminant flakes and conductive films in the implanter.

In situ cleaning was performed by introducing XeF ₂ at regular intervals from its supply vessel located in the gas box of the ion implanter where the XeF ₂ cleaned steam was introduced into the ion source twice a day for 10 to 15 minutes. A high current injector was used to test the fluid dynamics of the cleaning agent. XeF ₂ cleanliness was determined and it was confirmed that the cleaning agent did not adversely affect the beamline component of the injector. The cleaning process with XeF ₂ reagent is suitable for use in intermediate current injector devices.

Figure 1 is a graph of regulated source life data from an intermediate current injector before and after the in-situ cleaning process. Data were developed for a dopant composition comprising arsine and phosphine. Prior to cleaning, the ion source had an average operating life of about 250 +/- 90 hours, which is limited by two common failure modes.

The main mode of failure was excessive leakage from the suppressor voltage supply. For successful extraction of a stable ion beam, an inhibitor voltage is supplied to an electrode located outside the arc chamber. The electrodes are electrically insulated by a number of small insulators, which can lead to excessive suppressor leakage due to the accumulation of the conductive film on one or more of these insulators.

The second mode of failure was a short circuit of the components in the arc chamber due to the flaking of the deposited material.

These failure modes were found to be minimized by the in situ chemical cleaning process. Two regular daily rinses increased the life of the source in production.

The effect of XeF ₂ on suppressor leakage current is further illustrated in FIG. 2, and FIG. 2 is a graph of leakage current for intermediate current means before and after introduction of in-situ cleaning. Each data point represents the average suppressor current for the time required to inject the wafer lot, and the points were plotted over the life of several ion sources. The magnitude of the leaks depends on the elapsed time since the replacement of the insulator in the last preventive repair. The data show that periodic in-situ cleaning greatly reduces leakage currents and never reaches the control upper limit of 1.5 mA, which requires unscheduled source maintenance.

The in-situ cleaning effect was also evaluated using an injected dopant mixture containing BF ₃ and PH ₃ . The source was driven under these conditions for 497 hours and failed for arc limited conditions, including deposition of tungsten or boron over the filament due to BF ₃ chemistry. The single source life of 497 hours in the test system is compared to the historical average of 299 hours in the same system. This is a single data point, but it corresponds to the established pattern. The improvement in the source life in this case appears to be due to the etching of the tungsten deposits in the source arc chamber with XeF ₂ .

The photographs of Figures 3a and 3b provide additional evidence of the effectiveness of the detergent. In both figures, the appearance of the ion source housing is shown after about 98 days of production, after removal of the ion source assembly for periodic preventive maintenance. In the case of the photograph of FIG. 3A, the cleaning in the original position was carried out twice a day, whereas in the case of the photograph of FIG. 3B, the cleaning was not performed.

When not cleaned, there was a significant amount of deposited material, some of which began to delaminate and begin to flake. During regular maintenance activities, the hands were rubbed to remove deposited material from the inner surface of the housing. With in-situ cleaning, the housing looked much cleaner and took little or no time to clean by hand. The unreacted XeF ₂ was sent out of the arc chamber, sent to the vacuum chamber wall, and the deposit was removed by chemical removal of the dopant and other deposits.

Deposits inside and around the ion source cause so-called "injector memory effect ". By replacing one dopant source gas with another, ions from the first dopant element continue to be extracted from the ion source plasma long after the first dopant gas is terminated. In some cases, this effect causes a severe contamination of the desired ion beam and adversely affects the implantation process.

One example of an injector memory effect is P contamination in a BF ₂ injector. The impact of this pollution on process yield is so severe that many semiconductor manufacturing facilities avoid the phosphorus and boron injection plans on the same equipment. This is a significant hurdle in planning injection operations. P / BF ₂ contamination is generated from phosphorus deposits at the source from the injection with PH ₃ . When BF ₂ ⁺ is converted to BF ₃ gas, some of the fluorine reacts to form ³¹ P ¹⁹ F ⁺ . The mass of ³¹ P ¹⁹ F ⁺ is 50. This is close enough to the preferred mass of ¹¹ < ^{19 &} _gt ; F ₂ of 49 that PF ⁺ is implanted with PF ⁺ ions. As a result, BF ₂ ⁺ injection is limited to some high-current systems with bounded mass resolution in a particular mass-energy range.

XeF ₂ cleaning was evaluated using a high current injector operated for approximately 200 hours in simulated production with a P ⁺ ion beam from PH ₃ dopant gas to determine the effect on injector memory effect. The system was converted to BF ₃ gas and bare silicon monitor wafers were immediately implanted using high capacity (5 ^x 10 ¹⁵ ions / cm ² ) BF ₂ ⁺ . During the BF ₂ ⁺ injection, the resolution aperture of the system analyzer magnet was opened more than usual to allow the contamination effect to be large enough for convenient measurement using secondary ion mass spectrometry (SIMS) analysis.

The cleaning effects of BF ₃ , argon and XeF ₂ were compared by periodically monitoring the amount of contaminants remaining on the injection monitor wafer using BF ₂ ⁺ after driving three gases, BF ₃ , argon and XeF ₂ , respectively. The amount of P injected with BF ₂ was measured by SIMS. A typical SIMS spectrum of injected phosphorus is shown in Figure 4a where the peak of the in-spectrum corresponds to the injected depth of PF ⁺ ions extracted from the ion source and the dose corresponds to a contamination level of about 3% PF in BF ₂ do.

FIG. 4B is a plot of contaminant levels as a function of cleaning time with either BF ₃ or XeF ₂ , wherein the plot is normalized for contamination levels immediately after conversion from PH ₃ to BF ₃ . When BF ₃ plasma was driven, it had little effect on PF contamination even after 2 hours. A similar result (not shown) was obtained when argon plasma was used. In contrast, PF contamination was reduced by a factor of 2 after washing in situ for only 15 minutes with XeF ₂ , and after 5 minutes of washing in the home position with XeF ₂ for 30 minutes.

Before using the in-situ cleaning, the intermediate current injection unit replaced an average of 3.3 sources per unit per month, and the average source change and subsequent qualification tests required about 5 hours, which resulted in a production time of 200 hours per equipment Loss. The source lifetime was effectively doubled by in-situ cleaning and added about 100 hours of production time per intermediate current device. As a result, test wafers are saved, measurement equipment required for post-processing of qualifying wafers and machining time are reduced (40 qualification tests per year are performed for each intermediate current injector), demonstrating the effectiveness of in-situ cleaning Respectively.

Example 2

This example demonstrates control of filament growth in an ion source of an exemplary ion implanter system.

5A is a graph showing the effect of XeF ₂ flow and arc power changes on increased filament current and weight. The graph represents the weight (in g) of the filament as a function of the elapsed operating time (expressed in hours) of the injector system. The line at the top of the graph represents the operation at 2.2 standard cubic centimeters per minute (sccm) XeF ₂ flow and 100 volts / 0.05 amp arc power where the filament weight was measured as 319 mg / hr increase after 3 hours of operation. The lower line of the graph reflected an arc power of 0.5 sccm of XeF ₂ flow and 40 volts / 0.05 amp, which increased the filament weight to 63 mg / hr for an operating time of 3 hours.

5B is a graph showing the effect of XeF ₂ flow and arc power change on filament current. The graph shows the filament current (in amperes) as a function of the operating time of the injector system. The upper line in the graph represents the operation at an XeF ₂ flow of 2.2 standard square centimeters per minute (sccm) per minute and an arc power of 100 volts / 0.05 amp, where the filament current was measured as a 16 amp / h rise. The lower line of the graph reflected a 0.5 sccm XeF ₂ flow and an arc power of 40 volts / 0.05 amps, which increased the filament current of 2.3 amps / hr for an operating time of 3 hours.

Figure 6 is a graph of filament weight change (in mg / h) as a function of average filament current (in ampere units). The graph shows the effects of plasma conditions and high temperature flow (no plasma) for tungsten transport, data on low flow and high flow high temperature filament conditions and data on low flow and high flow plasma conditions. These data demonstrate that the migration of tungsten in the system can be selectively controlled by selecting the appropriate process conditions for depositing or otherwise etching the material in the filament.

Example 3

This embodiment shows improvements in ion source lifetime and injector use achievable by monitoring cathode bias power supply. Figure 7 is a graph showing changes in the cathode bias power as a function of time and gas type. Specifically, when GeF ₄ flows, the hydrogen cycle causes deposition on the cathode of W, which results in an increase in bias power (to maintain the set ion beam current). When PH ₃ flows, phosphorus ions sputter the cathode, resulting in a drop in cathode bias power. In this embodiment, the ratio of PH ₃ : GeF ₄ is such that the bias power ultimately reaches a maximum output after about 76 hours. Monitoring bias power in this manner and taking proper action will improve the life of the ion source.

FIG. 8 is a graph showing the change in cathode W weight as a function of bias power. As Specifically, the source gas, the use of XeF _2, tungsten (W), can be simply capping the cathode by changing the bias power, or etched from the cathode draw cache deposited on the cathode. The high bias power increases the temperature of the cathode to the level where the W deposition reaction is favored, while the low or medium bias power lowers the temperature to the point where the W etch reaction is favored. Depending on the state of the cathode, the bias power may be selected to either etch unwanted deposits from the cathode or re-deposit the required W by the cathode, thus improving ion source lifetime.

While the present invention has been disclosed herein with reference to various specific embodiments, it will be apparent to those skilled in the art that the present invention is not limited thereto but extends to and encompasses various other modifications and embodiments. Accordingly, the present invention is intended to be broadly construed and interpreted in accordance with the appended claims.

Claims

(a) determining a power usage for an indirectly heated cathode supply by measuring a cathode bias power at a predetermined time;
(b) comparing the power usage at the predetermined time zone with the initial power;
(c) in response to the comparison, taking a correction action by varying the cathode bias power to control the condition of the indirectly heated cathode, the correction action comprising: (i) (Ii) indirectly re-growing the heated cathode if the power usage at a predetermined time zone is lower than the initial power, if the power usage is higher than the initial power;
A method for controlling conditions of a cathode source indirectly heated in an ion implantation system.

The method according to claim 1,
(i) of (c) controls the condition of the indirectly heated cathode source in the ion implantation system, including manipulating the indirectly heated cathode under conditions of low to intermediate temperatures sufficient to etch How to.

The method according to claim 1,
wherein the regrowth of step (c) (ii) comprises flowing a fluorinated gas in a plasma state over indirectly heated cathodes.

The method of claim 3,
A fluorinated _{gas, XeF 2, XeF 4, XeF} 6, GeF 4, SiF 4, BF 3, AsF 5, AsF 3, PF 5, PF 3, F 2, TaF 3, TaF 5, WF 6, WF 5, _{WF 4, NF 3, IF 5} , IF 7, KrF 2, SF 6, C 2 F 6, CF 4, ClF 3, N 2 F 4, N 2 F 2, N 3 F, NFH 2, NH 2 F, C ₂ H ₄ , C ₃ F ₈ , C ₄ F ₈ , C ₅ F ₈ , CHF ₃ , CH ₂ F ₂ , CH ₃ F, COF ₂ , HF, C ₂ HF ₅ , C ₂ H ₂ F ₄ , C ₂ H A method of controlling conditions of a cathode source indirectly heated in an ion implantation system, comprising at least one of: ₃ F ₃ , C ₂ H ₄ F ₂ , C ₂ H ₅ F, C ₃ F _6, and MoF ₆ .

The method according to claim 1,
(ii) regulates the conditions of an indirectly heated cathode source in the ion implantation system, including manipulating the indirectly heated cathode under conditions of high temperature sufficient for metal deposition to occur. How to.

5. The method of claim 4,
A fluorinated gas, XeF ₂ and N ₂ F ₄ A method of controlling the ion implantation conditions of the system indirectly heated cathode sources in comprising at least one of.

(a) a condition for performing tungsten deposition on the cathode, wherein the temperature of the cathode is greater than 2000 占 폚 and the temperature of the wall of the arc chamber is less than the cathode temperature; And
(b) from the cathode, the condition of performing the etching of the deposited material, wherein the temperature of the cathode is lower than 2000 ° C and the temperature of the wall of the arc chamber is lower or higher than the temperature of the cathode
And contacting the cathode with a tungsten reagent under conditions selected from the group consisting of < RTI ID = 0.0 >
Wherein the contact is such that the contact maintains the power consumption of the cathode within a predetermined threshold comprising at least the predetermined electrical resistance and is selected such that the temperature of the cathode and the temperature of the arc chamber Which is performed in accordance with a schedule for independently controlling the temperature of the wall,
A method of operating a cathode-containing ion implantation system in an arc chamber of an ion source to maintain operation efficiency of the ion source.

(a) conditions for performing material deposition on the cathode; And
(b) conditions for performing etching of the deposited material from the cathode
And flowing the cleaning gas through the ion implantation system under conditions selected from the group consisting of:
Wherein the cleaning gas comprises XeF ₂ and the cleaning gas flows through the system at an interval sufficient to maintain the leakage current from the suppressor voltage supply below the predetermined limit during operation of the system. For removing at least partially the ionization-related deposit from the ion implantation system.

The method according to claim 6,
A fluorinated gas, a method of controlling the conditions of the indirect cathode heating source as in the ion implantation system including an XeF _2.

The method according to claim 6,
Wherein the fluorinated gas comprises N ₂ F ₄ , wherein the condition of the indirectly heated cathode source in the ion implantation system is controlled.