JP3935850B2 - Plasma processing equipment - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a plasma processing apparatus and a plasma processing method, and more particularly to a plasma processing apparatus and a plasma processing method capable of suppressing the generation of foreign matters due to reaction products.
[0002]
[Prior art]
As a material to be etched used in the semiconductor device manufacturing field, a volatile material such as Si, Al, or SiO 2 is used for a DRAM (Dynamic Random Access Memory) or a logic circuit IC. Also, non-volatile materials such as Fe are being used for FRAM (Ferroelectric Random Access Memory) or MRAM (Magnetic Random Access Memory).
[0003]
The nonvolatile material is difficult to etch because the melting point of the reaction product generated during the etching is high. In addition, since the vapor pressure of the reaction product after etching is low and the coefficient of adhesion to the inner wall of the vacuum vessel (vacuum processing chamber) is high, the inner wall of the vacuum vessel can be formed only by processing a small number (several to several hundreds) of samples. It will be covered by deposits of reaction products. Further, when this deposit is peeled off, foreign matter is generated.
[0004]
When the reaction product is deposited, the coupling state between the induction antenna and the plasma in the reaction vessel changes, and the etching rate, the uniformity thereof, the etching perpendicularity, the adhesion state of the reaction product to the etching sidewall, and the like change with time.
[0005]
Specific examples of the non-volatile material include Fe, NiFe, PtMn, IrMn, a DRAM capacitor portion and a gate portion, and a FRAM capacitor portion used as a ferromagnetic or antiferromagnetic material for an MRAM or a magnetic head. And Pt, Ir, Au, Ta, and Ru, which are noble metal materials used for TMR (Tunneling Magneto Resistive) element portions of MRAM. In addition, Al, a high dielectric material ₂ O ₃ , HfO ₃ , Ta ₂ O ₃ Examples thereof include PZT (lead zirconate titanate), BST (barium strontium titanate), SBT (strontium bismuth tantalate), and the like, which are ferroelectric materials.
Similarly, in the semiconductor device manufacturing field, Si or SiO is used as a semiconductor device manufacturing process. ₂ Alternatively, a technique for forming a SiN film by plasma CVD is frequently used. In this technique, a polymerizable gas such as monosilane is incident on plasma to form a film on a wafer. At this time, a large amount of the polymerized film adheres to the inner wall of the reaction vessel other than the wafer, which hinders mass production stability. That is, if the polymer film is deposited too thickly on the inner wall of the reaction vessel, the polymer film is peeled off from the inner wall surface and adheres to the wafer as a foreign substance as in the case described above. For this reason, NF ₃ It is necessary to carry out plasma cleaning using a violent special gas such as the above, or manual cleaning performed by opening the reaction vessel.
[0006]
In the field of semiconductor device manufacturing, SiO ₂ The plasma dry etching process is frequently used. In this etching, C ₄ F ₈ , C ₅ F ₈ , CO, CF ₄ , CHF ₃ Or the like is used as an etching gas. Reaction products produced by the reaction of these gases in plasma include C, CF, C ₂ F ₂ When free radicals such as the above are contained and these free radicals are deposited on the inner wall of the reaction vessel, foreign substances are generated as in the case described above. Further, when free radicals are re-evaporated from the deposited film into the plasma, the chemical composition in the plasma changes, and the etching rate of the wafer changes over time. As a conventional plasma processing apparatus, an induction type plasma processing apparatus in which a coiled antenna is provided on the outer periphery of a vacuum container, a plasma processing apparatus for introducing a microwave into the vacuum container, or the like is known. In any of these processing apparatuses, countermeasures against deposits on the inner wall of the vacuum vessel when etching a non-volatile material are not sufficient, and thus manual cleaning with opening to the atmosphere is repeated. When the manual cleaning is started, it takes 6 to 12 hours to start the processing of the next sample, so that the operation efficiency of the apparatus is lowered.
For example, in Patent Documents 1, 2, and 3, a plasma is generated in a processing vessel by an induction method, and a Faraday shield is provided between the induction antenna provided on the outer periphery of the vacuum vessel and the plasma, and a high-frequency power source is provided to the Faraday shield. A plasma processing apparatus is shown that can reduce the adhesion of reaction products to the inner wall of the vacuum vessel or can clean the inner wall of the vacuum vessel by connecting and supplying power.
[0007]
This apparatus is effective for a portion of the vacuum vessel that is formed of a non-conductive substance, that is, ceramic or quartz, and a portion where the electric field due to the Faraday shield is sufficiently reached. However, it is not effective for portions formed of other non-conductive materials or portions formed of conductive materials.
[0008]
[Patent Document 1]
JP-A-10-275694
[0009]
[Patent Document 2]
Japanese Patent Laid-Open No. 11-61857
[0010]
[Patent Document 3]
JP 2000-323298 A
[0011]
[Problems to be solved by the invention]
As described above, when the reaction product is excessively deposited on the inner wall of the vacuum vessel, the deposited film is peeled off from the inner wall surface and adheres to the wafer as foreign matter. In addition, in the plasma processing apparatus using the induction antenna, the coupling state between the induction antenna and the plasma in the reaction vessel changes, and the etching rate, the uniformity thereof, the etching verticality, the adhesion state of the reaction product to the etching sidewall, etc. Change. Further, when cleaning the inner wall of the vacuum vessel, it takes time to start the processing of the next sample, so that the operation efficiency of the apparatus is lowered. In addition, by providing a Faraday shield between the induction antenna provided on the outer periphery of the empty container and the plasma, and connecting the high-frequency power supply to this Faraday shield and supplying power, the adhesion of reaction products to the inner wall of the vacuum container is reduced. Alternatively, the effective range of the plasma processing apparatus that can clean the inner wall of the vacuum vessel is limited.
[0012]
The present invention has been made in view of these problems, and provides a plasma processing apparatus that controls a deposited film deposited on the inner wall of a vacuum vacuum vessel and is excellent in mass production stability.
[0013]
[Means for Solving the Problems]
The present invention employs the following means in order to solve the above problems.
[0014]
A gas ring that constitutes a part of the vacuum processing chamber and includes a processing gas blowout port; and Placed on top of it A mounting table on which the sample is mounted; a bell jar disposed above the gas ring to form an upper part of the vacuum processing chamber and covering the plasma generation space above the mounting table; and a bell jar disposed on the outer periphery of the bell jar. A coiled antenna that supplies a high-frequency electric field for generating plasma in the plasma generation space; a Faraday shield that is disposed between the antenna and a bell jar and is applied with a high-frequency bias voltage; An adhesion preventing plate that is detachably disposed on the vacuum processing chamber side and has an opening for allowing the processing gas flowing out from the processing gas outlet to flow therethrough, The gas ring is arranged to be positioned above the mounting table, The opening of the deposition preventing plate is connected to the processing gas blowout port through the opening. Outside the prospective angle It arrange | positioned in the said plasma production space direction so that the said sample might be included.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
A first embodiment of the present invention will be described below with reference to the drawings. In the first embodiment, a method for suppressing deposition of reaction products on the inner wall of a vacuum vessel during processing will be described by taking an example of etching processing when a sample to be plasma processed is a nonvolatile material.
[0016]
FIG. 1 shows a cross-sectional view of the plasma processing apparatus according to the present embodiment. The vacuum vessel 2 includes a bell jar 12 made of an insulating material (for example, a non-conductive material such as quartz or ceramic) that closes an upper portion thereof to form a vacuum processing chamber. Inside the vacuum vessel, there is provided a mounting table 5 for mounting a sample 13 to be processed, and plasma 6 is generated in the processing chamber to process the sample. The mounting table 5 is formed on the material holding unit 9 including the mounting table.
[0017]
On the outer periphery of the bell jar 12, a coiled upper antenna 1a and lower antenna 1b are arranged. A disc-shaped Faraday shield 8 that is capacitively coupled to the plasma 6 is provided outside the bell jar 12. The antennas 1a and 1b and the Faraday shield 8 are connected in series to a high frequency power source (first high frequency power source) 10 via a matching unit (matching box) 3 as will be described later. Further, a series resonance circuit (variable capacitor VC3 and reactor L2) capable of changing the magnitude of impedance is connected in parallel between the Faraday shield 8 and the ground.
[0018]
A processing gas is supplied into the vacuum vessel 2 through a gas supply pipe 4a. The gas in the vacuum vessel 2 is evacuated to a predetermined pressure by the exhaust device 7. A processing gas is supplied into the vacuum vessel 2 from the gas supply pipe 4a, and in this state, the processing gas is turned into plasma by the action of an electric field generated by the antennas 1a and 1b. A substrate bias power source (second high frequency power source) 11 is connected to the mounting electrode 5. Thereby, ions present in the plasma 6 can be drawn onto the sample 13.
[0019]
As the high frequency power source 10, for example, a high frequency power in the HF band such as 13.56 MHz, 27.12 MHz, 40.68 MHz, or a high frequency power source in the VHF band having a higher frequency is used. By supplying to 1 b and the Faraday shield 8, an electric field for generating plasma can be obtained in the vacuum vessel 2. At this time, by using the matching unit (matching box) 3, the impedance of the inductively coupled antennas 1 a and 1 b can be matched with the output impedance of the high-frequency power source 10, thereby suppressing power reflection. As the matching unit (matching box) 3, for example, as shown in the figure, a capacitor in which variable capacitors Vc1 and Vc2 are connected in an inverted L shape is used.
[0020]
As shown in FIG. 2, the Faraday shield is made of a conductor having a vertically striped slit 14 and is disposed so as to overlap with a ceramic vacuum vacuum container (Berger 12). The voltage applied to the Faraday shield 8 can be adjusted by the variable capacitor (VC3 shown in FIG. 1). The voltage (shield voltage) applied to the Faraday shield 8 may be set to an arbitrary value corresponding to the processing recipe for each wafer or corresponding to the cleaning processing recipe.
[0021]
The principle of cleaning the inner wall of the vacuum vessel by the Faraday shield is that a high-frequency voltage applied to the Faraday shield generates a bias voltage inside the vacuum vessel (the inner wall of the bell jar), thereby drawing ions in the plasma into the vacuum vessel wall, The drawn ions are bombarded against the vacuum vessel wall to cause physical / chemical sputtering, thereby preventing reaction products from adhering to the vacuum vessel wall. There is an optimum Faraday Shield Voltage (FSV) for cleaning the inner wall of the wall by the Faraday shield. The optimum FSV is affected by the high frequency power supply frequency, the vacuum vessel wall material, the plasma density, the plasma composition, the entire vacuum vessel configuration and the material of the workpiece, the processing speed, and the processing area. Therefore, the optimum value of the FSV needs to be changed for each process.
[0022]
FIG. 3 is a diagram for explaining a method for optimizing the FSV, and shows the relationship between the emission intensity (light quantity) of the FSV and the vacuum vessel wall material (for example, aluminum or oxygen constituting alumina when the wall material is alumina). It is a thing. As shown in the figure, the emission of the wall material becomes stronger when the FSV becomes higher than a certain FSV (point b in FIG. 3). This shows that deposits (depots) are deposited on the wall in the FSV below the b point, and not only the deposit is sputtered and deposited in the FSV above the b point, but the wall material itself is also sputtered. Is shown.
[0023]
The FSV optimum value is the voltage at point b, but depending on the process, point a may be the optimum value. For example, when the wall material is released into the gas phase by sputtering of the vacuum wall material, the processing reaction of the object to be processed or the reaction in the gas phase deviates from what is assumed, and the desired process cannot be executed. To do. That is, by setting the FSV to point a, deposition of a small amount of deposit is recognized on the inner wall of the vacuum vessel, thereby preventing the wall material from being sputtered at all. This makes it possible to prevent process failures due to the release of the wall material. However, before the deposit is sufficiently deposited on the inner wall of the vacuum vessel, it is necessary to clean the inner wall of the vacuum vessel using a process dedicated to cleaning (here, FSV is set higher than the point b).
In contrast to the above, there is also a process for setting the point c to an optimum value. For example, if any reaction product accumulates even a little on the inner wall of the vacuum vessel, foreign matter is generated, or high frequency power for generating plasma is absorbed by the deposit, and the characteristics of the plasma change to stabilize the target process. It may not be possible to execute. In this case, the FSV is set to the point c as described above. That is, the inner wall may be slightly cut, but the reaction product may be set to a condition that does not accumulate at all. In this case, there is a disadvantage that the exhaustion of the vacuum container increases, but the number of cleaning of the inner wall can be reduced.
[0024]
If neither the inner wall scraping nor the reaction product deposition is desired, the FSV is set at the point b. At this time, it is important to improve the reproducibility of the set voltage of the FSV. This is because it is necessary to suppress a change with time when the same process is performed in different apparatuses or when the same process is continuously performed in the same apparatus. For this purpose, feedback control of the FSV is important.
[0025]
FIG. 4 is a diagram for explaining feedback control of FSV. As shown in the figure, the output of the plasma generating high-frequency power supply 10 is applied to the Faraday shield 8 via the impedance matching devices (VC1, VC2) and the antennas 1a, 1b. The FSV is divided by capacitors C2 and C3 to form a small signal. After removing harmonics and other frequency components through the filter 15, the detector 16 detects the signal, converts it to a DC voltage, and amplifies it by the amplifier 17. In this way, a DC voltage signal proportional to FSV is obtained. This signal is compared with a preset value or a set value set by the comparator 18 in the recipe output of the main unit control unit 20, and a variable capacitor for controlling the motor via the motor controller 19 to determine the voltage of the FSV. Rotate VC3. As a result, the FSV can be controlled to a value set by the main device control unit 20, and for example, even when different processes or the same apparatus processes the same process continuously, the FSV value can be controlled to be constant. . In addition, it is possible to suppress disparity between devices and changes with time.
[0026]
The Faraday shield is capacitively coupled to the plasma through the wall (belger) of the dielectric vacuum vessel. As a result, the FSV is divided by the capacitance between the Faraday shield and the plasma and the capacitance by the ion sheath formed on the wall, and the voltage after the division is applied to the ion sheath. As a result, the ions are accelerated and the inner wall of the vacuum vessel is subjected to ion sputtering. For example, when the wall thickness of an alumina vacuum vessel is 10 mm, the voltage applied to the ion sheath is about 60 V when the FSV is 500 V.
[0027]
It is useful to increase the voltage applied to the ion sheath with a low FSV. This is because the generation of a high FSV makes handling more difficult due to the fact that abnormal discharge tends to occur. In order to increase the voltage applied to the ion sheath with a low FSV, the capacitance of the ion sheath is uniquely determined by the plasma characteristics of the process used, so the capacitance between the Faraday shield and the plasma is made as small as possible. It is effective to do. In order to realize this, the dielectric constant of the material of the dielectric vacuum container is high, and the thickness of the wall of the dielectric vacuum container is made as thin as possible. As a material suitable for this, typical alumina can be adopted as a material having high strength and high dielectric constant.
[0028]
When a vacuum vessel with a thin wall thickness is made of a material having a high dielectric constant such as alumina, the problem is a gap between the Faraday shield and the wall (belger) of the vacuum vessel. Since the dielectric constant of alumina is about 8, when the wall thickness is 10 mm, the thickness is 10/8 = 1.25 mm when converted to the atmosphere. Here, assuming that the gap between the Faraday shield and the vacuum vessel is 0 to 1 mm, the distance between the Faraday shield and the plasma changes from 1.25 to 2.25 mm, which is almost half as large as the air. This means that the voltage applied to the ion sheath changes from about 33 V to 60 V under the above conditions.
[0029]
In this way, when the voltage applied to the ion sheath changes greatly, deposits (depots) adhere to parts of the inner wall of the vacuum vessel, and deposits do not adhere to other parts, and FSV is applied. By doing so, the effect of suppressing deposit adhesion is reduced. In order to prevent this, it is necessary to make the gap between the Faraday shield and the vacuum container constant, or to manufacture the Faraday shield with a thin film and make it closely contact with the vacuum container.
[0030]
It is easy to fabricate a Faraday shield by processing a metal plate, but it is not realistic to make the gap with the vacuum vessel wall (Berja) 0.5 mm or less. However, a conductive elastic body, for example, a conductive sponge, can be attached under the Faraday shield, and the gap between the Faraday shield and the vacuum vessel wall can be filled with the sponge.
[0031]
FIG. 5 is a view showing an example of attaching the Faraday shield to the bell jar. FIG. 5A is an example in which there is a gap between the Faraday shield 14 and the bell jar 12, and deposits are likely to be deposited on the inner surface of the vacuum container in the portion with the gap. On the other hand, deposits do not accumulate near the bottom of the gap. FIG. 5B is a diagram showing an example in which the gap is filled with an elastic conductor 12a, for example, a conductive sponge. Thereby, the Faraday shield 14 can acquire the same effect as having adhered to the bell jar 12. In addition, since conductive sponge has a large elasticity, it can fill a large and small gap flexibly.
FIG. 6 is a view for explaining the attachment structure of the deposition preventing plate, and FIG. 6 (a) shows the gas outlet 23 formed in the bottom of the bell jar 12 and the gas ring below it. When the plasma treatment is continued in this configuration, deposits are deposited in the portions indicated by A and B in the figure. Deposits can be prevented from being deposited on the inside of the bell jar and above the portion B in the figure due to the effect of ion sputtering by FSV. The problem here is the portion indicated by A and B. The portion A is the periphery of the gas ejection port 23. When deposits adhere to the gas ejection port 23, the deposits easily peel off due to the effect of the gas flow, and the peeled deposits are on the wafer to be processed. It becomes a foreign object and becomes an obstacle to the process. The portion B is the inner wall of the bell jar 12, but the Faraday shield 14 is far from the bell jar inner wall. For this reason, the ion sheath voltage by FSV falls and the deposit adhesion inhibitory effect by ion sputtering does not fully work.
[0032]
FIG. 6B is a diagram illustrating a structure in which the gas outlet 23 is covered with the deposition preventing plate 22. The portion A is near the gas outlet, and deposit adhesion to this portion needs to be reduced as much as possible. In order to reduce deposit adhesion to the gas blowing port 23, the plasma 6 region that can be seen from the gas blowing port 23 through the hole of the deposition preventing plate 22 is reduced, that is, the prospect angle for the plasma is reduced, and the gas blowing port 23 It is necessary not to look directly at the wafer, that is, to set the central axis of the gas outlet 23 in the direction of the plasma generation space above the sample so that the sample is included outside the expected angle.
[0033]
FIG. 6C is a diagram showing a detailed example of the relationship between the deposition preventing plate and the gas ejection port. In this example, the prospective angle is reduced to about 30 degrees, and the wafer is made invisible directly from the gas ejection port.
[0034]
At this time, it is effective to leave a gap between the deposition preventing plate 22 and the gas ejection port 23. The size of the gap is desirably 0.5 mm or more. This gap creates several advantages. First, even if the gas passage hole formed in the deposition preventing plate has the same size, the prospective angle to the plasma can be reduced by opening the gap, and the amount of deposits adhering to the gas ejection port 23 can be reduced. Further, when the gas is blown out from the gas ejection port 23 into the vacuum container, a large pressure drop occurs, and the flow moves from a viscous flow to an intermediate flow and finally becomes a molecular flow. Here, the gas pressure is still relatively high in the vicinity of the gas outlet 23 and is in an intermediate flow state. When deposits adhere to the gas outlets 23, the deposits are easily peeled off due to the force from the gas flow. By forming the gap, the gas flow in the vicinity of the deposition preventing plate 22 becomes a molecular flow, and the gas flow has less force to peel off the deposit attached to the deposition preventing plate, and the peeling of the deposit can be reduced. Furthermore, as will be described later, the temperature of the deposition preventing plate 22 can be increased efficiently, and the amount of deposits adhering to the deposition preventing plate 22 can be reduced.
[0035]
FIG. 7 is a diagram illustrating an example of heat calculation of the deposition preventing plate. From the results of the process treatment, it has been found that materials such as Fe and Pt hardly adhere to members having a temperature of 250 ° C. or higher. Therefore, the deposition preventing plate was designed so that the temperature of the deposition preventing plate was 250 ° C. or higher. In the thermal design, the heat balance of the three was calculated: heat input from the plasma, heat escape from the protection plate support, and radiation heat escape from the entire protection plate. The result of this heat calculation is shown in FIG.
[0036]
When the adhesion preventing plate is SUS (stainless steel), it can be seen that the equilibrium temperature exceeds 250 ° C. when the radio frequency (RF) input to the plasma is about 500 W. When the deposition preventing plate is made of Al (surface anodized), the deposition preventing plate equilibrium temperature is 250 ° C. or more when the RF input is 1000 W or more. The structural features of each part in the calculation will be described below.
[0037]
Since the plasma heat isotropically diffuses in the reactor, the plasma heat input is calculated as RF input to plasma x deposition plate area / total plasma contact area. In the adhesion plate specification designed this time, if the RF input to the plasma is 1200 W, the heat input to the adhesion plate is 260 W.
[0038]
The heat radiation escape from the adhesion-preventing plate can be suppressed to a low level because the surface radiation rate can be reduced to about 0.2 by using SUS as a material and having a mirror-finished surface. When Al (surface alumite treatment) is used for the adhesion-preventing plate, the alumite surface emissivity is about 0.6, so that the heat radiation escape becomes large.
[0039]
FIG. 8 is a view for explaining the support structure of the deposition preventing plate. The protection plate supports the entire circumference at three points so that the heat transfer from the support portion is reduced, and the contact area with the gas ring main body is almost point contact as shown in FIG. Suppressed. As a specific example, the contact portion radial length is 3 mm, and the contact portion circumferential length is 1 mm. Contact thermal resistance is 3000 [W / (m ² · K)] Even if estimated to be an excessive value, the heat transfer from the cover plate support portion calculated by contact area × contact heat transfer coefficient × (block plate inner surface temperature−gas ring temperature) is about 10 W It can only be.
[0040]
Actually, a protection plate was prototyped and the surface temperature was measured. The material of the deposition preventing plate used is Al (surface anodized). With an RF input of 1200 W, the surface temperature was about 250 ° C., and it was confirmed that the value was almost as designed.
[0041]
As described above, the adhesion preventing plate cannot completely eliminate the adhesion of the deposit even if it is maintained at a high temperature. For this reason, it is important to stably deposit the deposits attached to the deposition preventing plate. For this reason, it is desirable that the surface of the deposition preventing plate has some unevenness in order to improve the adhesion of the deposit mechanically. According to the inventors' experiment, it is known that the surface roughness is desirably 10 μm or more.
[0042]
However, when the deposit starts to adhere, the deposited deposit gradually increases in thickness from the state of the thin film. For example, the unevenness of 10 μm provided on the deposition preventing plate has an anchor effect for deposits having the same film thickness. However, the anchor effect decreases as the thickness of the deposited deposit increases. Therefore, in order to make the anchor effect work effectively from the initial state in which the amount of deposits is small to the state in which the amount of deposits has increased to some extent, two types of unevenness, for example, 10 μm unevenness and 100 μm unevenness are simultaneously applied to the surface. Is desirable. As a processing method for forming such unevenness, for example, knurl processing can be used for forming 100 μm unevenness, and blasting can be used for forming 10 μm unevenness.
[0043]
As described above, it is desirable that the surface of the deposition preventive plate be mirror-finished in order to raise the temperature of the deposition preventing plate, and that the surface be unevenly formed in order to stably deposit the deposit. Therefore, in reality, the surface of the deposition plate to which deposits adhere (surface facing the plasma) is uneven, and the surface to which deposits do not adhere (for example, between the deposition plate and the gas ejection port). The surface facing the gap can be mirror-finished. In addition, in order to reflect the heat radiated from the deposition preventing plate, it is desirable that the surface of the gas ring where the deposits do not adhere is mirror-finished.
[0044]
The size of the deposition preventing plate is desirably the minimum size for covering the gas outlet. This is because deposits are inevitably deposited on the protective plate, and a thermal history is generated on the protective plate in order to increase the temperature in order to reduce the amount of deposit attached. This is because the deposits are easily peeled off due to the difference in the amount of expansion and contraction due to heat between the deposits and the protective plate material.
[0045]
Further, it is desirable that the deposition preventing plate is made of an electrically conductive material and grounded. This is because the discharge becomes more stable when the ground contact area with respect to the high frequency for generating plasma is increased. In addition, when the deposit is charged, the deposit is easily peeled off by the repulsive force between the deposits due to the Coulomb force, so that the deposit is also prevented from being charged as much as possible.
[0046]
The structural design and the thermal design as described above were carried out to produce an adhesion-preventing plate having a surface roughness of 10 μm and 100 μm, and the performance was examined by etching 500 platinum Pt continuously. As a result, almost no deposit was found on the gas outlet. Moreover, the deposit adhering to the adhesion preventing plate was stable, and no peeling of the deposit occurred.
[0047]
9 is a portion B of FIG. 6 (a portion where the Faraday shield of the inner wall of the bell jar 12 is far from the inner wall of the bell jar. Therefore, a portion where the ion sheath voltage due to the FSV is lowered and the deposit adhesion suppressing effect due to the ion sputtering does not sufficiently work) It is a figure explaining the deposit countermeasure adhering to a.
[0048]
The portion B in FIG. 6 is a region where ion sputtering by FSV is difficult to work because the distance between the inner wall of the bell jar 12 and the Faraday shield 14 is long. Therefore, by extending the deposition preventing plate 22 and covering this portion, it is possible to reduce the deposit adhesion amount and stabilize the deposit. This structure is shown in FIG. 9 (a). When this was used to test the deposit adhesion, it was found that the deposit adhered to a region of about 15 mm width on the inner wall of the bell jar centering on point C in FIG.
[0049]
FIG. 9B is a modification of FIG. As shown in the figure, the bell jar 12 is formed so that the inner surface thereof is substantially continuous with the inner surface of the gas ring 4, and the bell jar 12 is disposed on the gas ring 4 to form a vacuum processing chamber.
[0050]
According to this configuration, the deposition preventing plate can be continuously formed on the inner surface of the bell jar and the inner surface of the gas ring. Thereby, the region where the ion sputtering by the FSV is difficult to work can be effectively protected by the deposition preventing plate.
[0051]
FIG. 10 is a diagram for explaining adhesion of deposits in the vicinity of the deposition preventing plate. First, the dotted lines indicate plasma isodensity lines. When attention is paid to the point C, the point C corresponds to a corner portion made of an adhesion preventing plate and a bell jar, and the plasma density in this portion is slightly lower than the surrounding area.
[0052]
This is because the plasma is less likely to go around the point C due to the thickness of the deposition preventing plate. For this reason, at point C, the number of ions sputtered per unit area of the inner wall of the bell jar is small, and it is considered that deposits are difficult to remove. There is another possible cause. That is, since the deposition plate is electrically conductive, the FSV is not effective on the ion sheath generated on the deposition plate, and a DC voltage of about 15 to 20 V determined by the plasma characteristics is applied to the ion sheath. On the other hand, in the region where FSV is effective, the ion sheath formed on the inner wall of the bell jar is applied with a high-frequency voltage of about 60 V, for example, on the DC voltage determined by the plasma characteristics. Sputter. That is, the vicinity of the point C corresponds to a transition region from the low voltage ion sheath generated on the deposition plate to the high voltage ion sheath formed on the inner wall of the bell jar, and is separated from the vicinity of the deposition plate near the point C. Accordingly, the voltage of the ion sheath is increased, and the region in which ion sputtering is gradually applied becomes a region.
[0053]
Due to the two causes described above, it is considered that a weak sputter region due to FSV is formed in the vicinity of point C as shown in FIG. In this region, it is considered that the deposit adheres because the deposit adheres more preferentially than the sputtering by FSV.
[0054]
11, 12, and 13 are diagrams showing examples of the structure of the adhesion preventing plate, respectively. As shown in FIG. 11, in order to remove the cause of the decrease in the plasma density, which is one of the causes of the formation of the weak sputter region, a knife edge-shaped deposition preventing plate was manufactured and tested. As a result, as shown in FIG. 11, it was confirmed that the weak sputter region was reduced and the deposit adhesion region was reduced. Therefore, in order to remove another cause, as shown in FIG. 12, when the upper portion 22a of the deposition preventing plate is changed to an insulator (in this case, alumina), as shown in FIG. Sediment areas could be matched and there was almost no deposit adhesion. Since the surface of alumina cannot be knurled, irregularities were processed on the surface by blasting. Also, quartz or aluminum nitride can be used as the insulator material.
[0055]
In order to prevent deposit adhesion more thoroughly, as shown in FIG. 13, it is sufficient that the strong sputter region is slightly larger than the deposit adhesion region. Therefore, a gap is provided between the deposition preventing plate and the bell jar so that plasma can enter between the deposition preventing plate and the bell jar. In order for the plasma to enter, the gap interval needs to be sufficiently larger than the ion sheath, and the gap interval needs to be 5 mm or more. On the other hand, if the size is too large, the deposit is wrapped around by diffusion, so that the effect is reduced. The maximum value of the gap to prevent the deposit from wrapping around is determined by the material / gas type of the deposit and its pressure, and therefore varies depending on the treatment process. However, the approximate result of the test is 15 mm. As a result of producing and carrying out a test of an anti-adhesion plate having the structure shown in FIG. 13, adhesion of deposits to the bell jar could be completely suppressed. In the case of this structure, the upper part of the protective plate does not need to be an insulating material, and the performance does not change even if it is made of an electric conductor.
[0056]
The upper part of the susceptor, which is the cover of the mounting table 5, also causes foreign matter generated on the wafer when deposits adhere. Therefore, a high frequency bias was also applied to the susceptor, and physical and chemical ion sputtering was caused to prevent deposits from adhering.
[0057]
FIG. 14 is a view showing the structure of the sample holder 9 including the mounting table. As shown in the figure, a mounting table to which the substrate bias power supply 11 is connected is mounted on the ground base 36 and the insulating base 35. As the material for the mounting table, aluminum or titanium alloy is generally used. A dielectric film is formed on the part on which the object to be processed (sample 13) is mounted at the upper part of the mounting table so that the object to be processed can be electrostatically adsorbed. Although the dielectric film is a sprayed film in the drawing, it may be formed of a polymer material such as epoxy, polyimide, or silicone rubber. In addition, as a ceramic material formed by thermal spraying or the like, there are alumina, aluminum nitride, and PBN (Pyrolytic Boron Nitride). Further, FIG. 14 shows a structure in which high-frequency power is shielded by using a grounding base 36 and an insulating cover 37 in order to prevent the high-frequency power from being released into the plasma from the side surface direction of the mounting table 5. The susceptor is generally made of quartz or alumina, and covers the electrode portion other than the surface on which the sample of the mounting table is mounted to prevent damage by plasma.
[0058]
FIG. 15 is a diagram showing a substrate bias circuit (equivalent circuit) including the susceptor surface. The substrate bias power supply 11 is mixed with the direct current voltage for electrostatic attraction supplied from the electrostatic attraction power supply in the impedance matching unit (MB) 32 and then supplied to the mounting table. Here, the high frequency of the substrate bias power supply 11 passes through the susceptor 34 from the mounting table 5 and is also supplied to the upper surface of the susceptor. At this time, the susceptor 34 forms a capacitor using a susceptor material as a dielectric. In FIG. 15, the capacitor formed in this way is represented as a capacitor C (33).
[0059]
The inventors first examined the deposit adhesion when the susceptor thickness was 5 mm as shown in FIG. As a result, it was found that a large amount of deposits adhered to the upper surface of the susceptor.
[0060]
Therefore, the relationship between the thickness of the susceptor 34 and the bias voltage generated on the susceptor surface was theoretically examined. The result is shown in FIG. It has been found that when the voltage generated on the inner wall of the bell jar is about 60 V or more, deposit adhesion can be suppressed. Further, in the tests of the inventors, the bias voltage (peak-to-peak) Vpp at the time of the test was often set to a range of about 400 to 500 V. Therefore, the bias voltage Vpp was 60 V or more on the susceptor surface within this range of the bias voltage Vpp. A susceptor thickness of 4 mm was selected so that a voltage could be generated.
[0061]
FIGS. 17 and 18 are diagrams for explaining the state of deposit attachment to a thin-walled susceptor (for example, 4 mm thick). As shown in FIG. 17, the entire surface of the susceptor was set to a thickness of 4 mm, and the deposition state of the deposit was tested. As a result, it was confirmed that there was no deposit adhering in the range indicated by the arrows in the figure (depot adhesion limiting region). Thereby, it turned out that deposit adhesion can be suppressed in the part which is in direct contact with the mounting table. However, in the configuration of FIG. 17, deposits adhere to the outer peripheral portion of the upper surface of the susceptor, and there is a concern that this may become a foreign substance on the object to be processed and hinder processing. Therefore, except for the insulating cover 37 formed on the side surface of the mounting table, the mounting table and the susceptor are in contact with each other over the entire upper surface of the susceptor and the side surface of the susceptor. This configuration is shown in FIG. Using the structure shown in FIG. 18, the state of deposit adhesion was experimentally investigated in the same manner as described above. As a result, deposits were not adhered on the susceptor upper surface and the susceptor upper surface in contact with the mounting table. However, it has been found that if the susceptor is repeatedly attached and detached, the deposit may not be removed sufficiently even under the same conditions. In addition, it was found that when this deposit could not be removed sufficiently, the deposit was deposited with an uneven distribution, and in particular, the deposit was likely to remain on the side surface of the susceptor.
[0062]
The deposits were deposited in a distribution with a bias, and the reason why the deposits could not be fully removed was estimated as follows. That is, the material of the susceptor is alumina, the thickness thereof is 4 mm, and the dielectric constant is about 8, which corresponds to about 0.5 mm when converted to an air layer. Here, if the gap between the susceptor and the mounting table is 0.1 mm, for example, the thickness of the dielectric forming the capacitor C in FIG. 15 is 0.5 mm for the susceptor and 0 to 0.1 mm for the gap. Total, varies from 0.5 to 0.6 mm (20%). This fluctuation causes a bias in the high-frequency voltage generated on the susceptor surface, thereby causing a bias in how to remove the deposit. However, it is difficult to manufacture the susceptor and the mounting table in close contact with each other with an accuracy of 0.1 mm or less, which is not practical.
[0063]
In order to solve this, as shown in FIG. 19, a metal film is sprayed on the lower surface of the susceptor 34 to form a metal spray film 39. Tungsten was used as the sprayed metal because it is known that it has good adhesion to alumina. The metal film need not be tungsten if it has electrical conductivity and good adhesion to the susceptor, and gold, silver, aluminum, copper, etc. are also possible. Also, the metal film manufacturing method does not have to be thermal spraying, and any method can be used as long as it can form a thin film such as plating, sputtering, vapor deposition, printing, coating, and thin film adhesion. By adopting this structure, if the metal film and the mounting table 5 are in contact with each other at one place, the same voltage as the mounting table is generated on the entire metal film, so the problem of the gap between the susceptor and the mounting table can be avoided.
[0064]
As a result of investigating the adhesion state of the deposit by an experiment using the apparatus configuration of FIG. 19, the adhesion of the deposit could be eliminated with good reproducibility within the deposit adhesion restricted region indicated by the arrow. The advantage of this method is that if the metal film and the mounting table are in contact with each other, the same voltage as that of the mounting table 5 is generated on the entire metal film, and a uniform high-frequency voltage can be generated on the surface of the susceptor 34. Therefore, as shown in FIG. 20, even when there is another structure such as the insulating cover 37, a uniform high frequency voltage can be generated on the surface of the susceptor in an arbitrary range by expanding the spraying range of the metal sprayed film. . In the configuration of FIG. 20, it was experimentally confirmed that deposit adhesion can be eliminated with good reproducibility in the deposit adhesion limited region indicated by the arrow.
[0065]
From the above results, it was found that by using a metal film such as metal spray, a high-frequency voltage can be uniformly generated on the susceptor surface, and the deposit adhesion can be suppressed uniformly. When this technique is used, the same effect can be obtained by embedding a metal film in the susceptor even when the thickness of the susceptor must be increased structurally. This structure is shown in FIGS.
[0066]
As shown in these drawings, a metal spray film 39 is embedded at a predetermined depth from the surface of the susceptor 34 (approximately 4 mm in the figure), and a contact is made from the metal spray film 39 to the mounting table 5 so as to be electrically connected. The conduction is ensured, and the same high frequency voltage as that of the mounting table 5 is generated on the metal sprayed film 39.
[0067]
The mounting table on which the sample 13 is mounted includes ceramic dielectrics such as aluminum nitride and alumina in addition to the type of forming an electrostatic adsorption film on a metal mounting table by thermal spraying as shown in the drawings. There is a type in which a metal electrode is embedded in a manufactured mounting table, and electrostatic adsorption or high frequency bias is applied from the metal electrode. Even in the case of this kind of mounting table, it is possible to manufacture a susceptor having exactly the same function by forming a metal film on the susceptor.
[0068]
Examples of this are shown in FIGS. FIG. 23 shows a case where a metal film is formed on the back surface of the susceptor 34. The mounting table 5 is made of aluminum nitride, and an electrostatic adsorption / high frequency bias application electrode 40 made of tungsten is embedded in the mounting table 5. From this electrode, a conductive pattern (the buttock conductive patterns 41, 42, 43) is embedded toward the metal sprayed film 39, whereby the electrode 40 and the metal sprayed film 39 are electrically connected. As a result, the same high frequency voltage as that of the tungsten electrode can be generated on the metal sprayed film 39 on the back surface of the susceptor. As a matter of course, the deposit adhesion control ability to the susceptor surface by this structure can be made exactly the same as described above.
[0069]
FIG. 24 shows an example in which a metal sprayed film 39 is embedded in the susceptor 34. The conductive pattern described in FIG. 23 (trunk conductive patterns 41, 42, 43) is extended and the mounting table 5 is embedded with contacts. If the metal sprayed film 39 buried in the electrode 40 and the susceptor 34 is connected, the function can be exactly the same as in the case of FIG.
[0070]
In the case of the mounting electrode 5 shown in FIGS. 23 and 24, a pattern for supplying a high frequency to the metal sprayed film 39 from the electrostatic adsorption / high frequency bias applying electrode 40 embedded in the electrode 5 is formed inside the mounting electrode 5. One example is shown in FIG. 25.
[0071]
In FIG. 25, the buttock conductive pattern 41, which is parallel to the tungsten electrostatic adsorption / high frequency bias applying electrode 40, embeds a tungsten thin film in the mounting electrode in the same manner as the tungsten electrode. These embedded tungsten thin films can be connected to each other by forming holes on necessary portions after forming the mounting electrodes and brazing the through terminals.
[0072]
In the bias application method for the susceptor described so far, when the high-frequency voltage of the mounting table is a certain value (here, 400 V), the deposit adhesion on the susceptor upper surface is just suppressed. However, when the voltage of the mounting table is increased, the high-frequency voltage on the upper surface of the susceptor becomes too high, and there is a disadvantage that the susceptor is scraped and the component life is shortened. This drawback can be solved by introducing means for adjusting the high-frequency bias voltage applied to the susceptor surface from the outside, as shown in FIG. FIG. 26 shows a circuit for adjusting the voltage of the metal film of the susceptor with a variable capacitor VC attached to the outside. This is shown in FIG. 27 as an actual structure.
[0073]
A ceramic coating 50 is formed on the surface of the mounting table in contact with the susceptor by thermal spraying or the like so that the susceptor metal sprayed film 51 and the mounting table 5 do not directly contact each other. This ceramic coating 50 forms a capacitor C ′ shown in FIG. 26 and has a function of transmitting a part of the high-frequency voltage applied to the mounting table 5 to the susceptor metal sprayed film 51. Then, the high frequency voltage applied to the mounting table 5 is transmitted to the susceptor metal sprayed film 51 by another external variable capacitor VC. Since the high-frequency voltages transmitted by the two capacitors have the same phase, they are simply added, and the high-frequency voltage generated on the susceptor surface is determined by the voltage. For example, the susceptor thickness is 4 mm, and the surface area of the susceptor metal sprayed film is 400 cm. ² Assuming that the ceramic film is 300 μm of alumina and the maximum capacity of the variable capacitor VC is 8000 pF, when the bias high frequency voltage of the mounting table is 400 V, the susceptor surface voltage is about 30 to 100 V when the capacity of the variable capacitor VC is varied. Variable in range. Thus, the high frequency voltage generated on the susceptor surface can be controlled by appropriately selecting the susceptor thickness, ceramic coating, metal spray coating surface area, and variable capacitor VC. Further, although the susceptor metal sprayed film at this time is not shown, it can be incorporated in the susceptor as long as it can be connected to the variable capacitor VC.
[0074]
In order to vary the bias applied to the susceptor, it is also possible to use a high-frequency power source different from the high-frequency power source 11 that supplies a high frequency to the mounting table. This is shown in FIG. Here, a susceptor bias power supply 11a for supplying a high frequency to the susceptor metal film is used separately from the substrate bias power supply 11 for supplying a bias to the mounting table. The electrode structure in this case is shown in FIG. What is important here is that an insulation and ground shield (grounding base 36) is provided between the mounting table 5 and the susceptor metal sprayed film 51 so that the high frequency voltage applied to the susceptor metal sprayed film 51 is not affected by the high frequency voltage of the mounting table 5. It is necessary to incorporate. Thereby, although there is a disadvantage that the susceptor bias power supply 11a is necessary, the bias applied to the susceptor can be controlled completely independently of the high-frequency voltage applied to the sample 13. Further, the susceptor metal sprayed film 51 at this time is not shown, but can be incorporated in the susceptor as long as it can be connected to the susceptor bias power supply 11a.
[0075]
FIG. 30 is a diagram for explaining a method of optimizing the susceptor bias voltage. Similar to the aforementioned FSV, the susceptor bias voltage has an optimum value. This voltage is influenced by the frequency of the bias power source, the susceptor material and thickness, the plasma density, the plasma composition, the entire vacuum vessel configuration and the sample material, the processing speed, and the processing area. Therefore, the optimum value of the susceptor bias voltage needs to be changed for each process. As in the case of FIG. 3, when the susceptor bias voltage increases with a certain value (point b in FIG. 30) as a boundary, the susceptor material emits light. When the susceptor bias voltage is lower than the point b, the deposit is deposited on the susceptor, and when the susceptor bias voltage is higher than the point b, the deposit is sputtered and not deposited, and the susceptor material itself is sputtered. Is shown.
[0076]
The optimum susceptor bias voltage is the voltage at point b, but it may be at point a depending on the process. This corresponds to a case where the susceptor material is released into the gas phase by sputtering of the susceptor material, and the sample processing reaction or reaction in the gas phase deviates from what is assumed, so that a desirable process cannot be performed. That is, by setting the susceptor bias voltage to point a, deposition of a deposit is recognized although it is slight on the susceptor, and the susceptor material is not sputtered at all. This is to prevent process failure due to the release of the susceptor material. Instead, it is necessary to clean the susceptor by a cleaning-dedicated process (here, the susceptor bias voltage is set higher than the point b) before the susceptor deposits are sufficiently deposited.
[0077]
On the other hand, if even a small amount of deposit adheres to the susceptor, the target process may not be stably executed due to the generation of foreign matters. In this case, the optimum point of the susceptor bias voltage can be set to the point c, and the susceptor may be slightly cut, but may be set to a condition in which no deposit is attached. In this case, there is a disadvantage that the consumption of the susceptor increases, but there is an advantage that the cleaning of the susceptor may be small.
[0078]
If both the susceptor scraping and deposit adhesion are desired, the susceptor bias voltage is set to the point b. At this time, it is important to improve the reproducibility of the set voltage of the susceptor bias voltage. This is because it is necessary to suppress a change with time when the same process is performed in different apparatuses or when the same process is continuously performed in the same apparatus. For this purpose, feedback control of the susceptor bias voltage is important.
31 and 32 are susceptor bias applying circuits with feedback control circuits corresponding to FIGS. 26 and 28, respectively. In both circuits, the voltage of the susceptor metal sprayed film is detected through an attenuator and a filter 52 and converted to a DC voltage. Thereby, this DC voltage signal becomes a signal proportional to the susceptor bias voltage. By comparing this signal with a preset value or a set value set by a recipe or the like of the main body device control unit 57, in the case of FIG. 31, the motor that rotates the variable capacitor VC that determines the susceptor bias voltage is controlled. In the case of FIG. 32, the output of the susceptor bias power supply 11a is controlled. By using this method, the susceptor bias voltage can be controlled to the value set in the main unit, and the susceptor bias voltage value can be kept constant when processing the same process continuously in different devices or the same device. It is possible to control, and to suppress the difference between devices and the change with time.
[0079]
The above has described the method and structure of the region to be controlled so as not to deposit or adhere deposits, that is, the bell jar 12, the gas outlet 23, and the susceptor 34. As long as the reactive organisms coming out of the sample 13 and the substances synthesized in the gas phase are volatile components having a high vapor pressure, these substances are exhausted from the discharge part and the periphery of the object to be processed by the exhaust device, and the electrodes Although some deposit in the lower part and the exhaust duct, most of them are exhausted.
[0080]
However, highly deposited substances, that is, vapor pressure is low and the adhesion coefficient to solids is close to 1 (almost trapped when contacted with solids) are used as sample reaction products or in the gas phase. If synthesized, these substances are deposited on the vacuum vessel wall including the bell jar, susceptor or gas outlet around the sample and are hardly exhausted.
[0081]
In such a situation, if the deposits are controlled not to adhere to any part in the vacuum vessel, these highly depositing substances lose their deposition sites. For this reason, the density in the gas phase of a highly depositing substance increases, and the driving force for the deposition increases. As a result, the material is forcibly deposited on a bell jar or a susceptor.
[0082]
That is, controlling the deposits not to adhere to the bell jar, the susceptor or the like produces the effect by preparing a place where the deposits are deposited in some amount. Then, by increasing the amount of deposits that can be deposited, or by quickly depositing from the gas phase, the deposit amount control capability of the deposits in the bell jar and the susceptor can be increased.
[0083]
In other words, a region (deposit trap region) for depositing a large amount of deposit quickly and in a large amount from the gas phase may be provided around the object to be processed in which a highly depositable reaction product is generated or around the plasma region. I need it. The deposition preventive plate functions as a cover that suppresses deposits from adhering to the gas outlet, but it is also a kind of trap because it is assumed that deposits accumulate on itself.
[0084]
FIG. 33 shows the inside of the vacuum vessel divided into regions including the deposit trap. First, the bell jar region and the wafer (sample) / susceptor region are regions that are controlled so as not to deposit deposits. All other areas in contact with the plasma are deposit trap areas, and the deposit trap area (1) is an area including the deposition plate and the lower part of the gas ring, and can be seen directly from the wafer (can be seen). It is an area. The bell jar region, the wafer / susceptor region, and the deposit trap region (1) are all regions that can be directly viewed from the wafer (can be seen), are regions that generate plasma, and from the wafer, Alternatively, a region having a strong deposition property formed in a plasma gas phase is most likely to adhere. If deposits are deposited in an uncontrolled state in these regions, foreign matter may be caused on the wafer or plasma may change over time. Therefore, in those areas that can be viewed directly from these wafers, deposit deposition must be controlled as completely as possible.
[0085]
In the present invention, when the structure shown in FIGS. 12 and 13 is used for the deposition preventing plate, 100% of the area that can be seen from these wafers is in a state in which the deposits are controlled. Further, even if the structures of FIGS. 6, 9, and 11 are used, it is necessary to control the deposits to 90% or more of the surface area of the region that can be viewed from these wafers.
[0086]
In addition, as described above, since the deposit trap region performs a sufficient function, the deposit suppression function of the bell jar region and the wafer / susceptor region can be enhanced, so that the surface area of the bell jar region and the susceptor region is as small as possible. It is desirable to make the surface area of the sediment trap region (1) as large as possible. When reactive organisms with strong deposition properties are generated from the wafer, assuming that the surface area of the wafer is SW, the surface area S1 of the deposit trapping area {circle around (1)} is S1 <0.5SW, and in the bell jar area or the wafer / susceptor area. It was found by experiments by the inventors that the sediment control function is reduced. Therefore, in order to quickly deposit reactive organisms in the sediment trap, a relationship of S1> = 0.5S1 is necessary, and S1> = S1 is desirable.
[0087]
The deposit trap region {circle around (2)} is called a ring cover and is located below the deposit trap region {circle around (1)}. Although this region cannot be desired directly from the wafer, a highly depositable material is transported by diffusion to adhere to the upper portion of the region. The deposit trap region {circle around (3)} is a cover on the side surface of the electrode, which cannot be directly desired from the wafer, but a large amount of deposit adheres to the upper portion like the deposit trap region {circle around (2)}. These deposit trapping areas (2) and (3) are areas that cannot be directly observed from the wafer, so it is unlikely that deposits adhering to these will become foreign matter on the wafer or cause changes in plasma over time. These sediment traps are important for efficient cleaning work when the apparatus is opened to the atmosphere. That is, since reactive organisms are highly depositable, 90% or more of them can be collected by depositing the deposit trap region (1), (2), and (3). Therefore, these deposit trap areas (1), (2), and (3) are made into swap kits (replaceable), and the interior of the vacuum vessel is efficiently cleaned by replacing all the parts that have been cleaned after being released into the atmosphere. It becomes possible. This requires two conditions for the sediment trap to be lightweight and easy to remove / install. In order to be lightweight, it is important that the material of the deposit trap is a lightweight member such as aluminum.
[0088]
After releasing the vacuum vessel to the atmosphere, remove the sediment traps (1) to (2) and (3) in order, and perform the minimum necessary cleaning operation. The minimum required cleaning place is, for example, the periphery of the wafer transfer opening. A swap kit of cleaned sediment traps can then be installed in reverse order and vacuum can be entered immediately. Thereby, the cleaning operation can be performed in a minimum time. Performing the cleaning operation in such a procedure not only shortens the cleaning time, but also shortens the time required for evacuation. The reason is that opening to the atmosphere for the minimum necessary time can minimize the moisture in the atmosphere that is adsorbed by non-vacuum components, and the minimum required amount of cleaning solvent (pure water, alcohol, etc.) This is because the amount of the solvent remaining in the vacuum vessel can be minimized by using. The removed sediment trap {1} {2} {3} is reused as a swap kit for the next air release / cleaning operation after cleaning. The area to be swapped as a sediment trap need not be limited to the area shown in FIG. Although it depends on the process and the material to be handled, it is efficient to make the entire region where the deposit adheres as a deposit trap. For example, when deposits adhere only to the upper half or more of the electrode cover, the upper half of the electrode cover is made into a swap kit. On the contrary, under the condition that the deposit adheres to the exhaust duct, the inner wall of the exhaust duct is also used as the deposit trapping region, and it becomes efficient if a swap kit is used.
[0089]
【The invention's effect】
As described above, according to the present invention, since the deposited film deposited on the inner wall of the vacuum vessel is controlled, it is possible to provide a plasma processing apparatus and a plasma processing method excellent in mass production stability.
[Brief description of the drawings]
FIG. 1 is a diagram showing a plasma processing apparatus according to an embodiment of the present invention.
FIG. 2 is a diagram showing a Faraday shield.
FIG. 3 is a diagram illustrating a method for optimizing an FSV.
FIG. 4 is a diagram for explaining feedback control of FSV.
FIG. 5 is a view showing an example of attaching a Faraday shield to a bell jar.
FIG. 6 is a view for explaining an attachment structure of a deposition preventing plate.
FIG. 7 is a diagram showing an example of heat calculation of a deposition preventing plate.
FIG. 8 is a diagram for explaining a support structure for an adhesion-preventing plate.
FIG. 9 is a diagram for explaining measures against deposits adhering to the inner wall of a bell jar.
FIG. 10 is a diagram for explaining adhesion of deposits in the vicinity of the deposition preventing plate.
FIG. 11 is a view showing an example of the structure of a deposition preventing plate.
FIG. 12 is a view showing another structure example of the deposition preventing plate.
FIG. 13 is a view showing still another structural example of the deposition preventing plate.
FIG. 14 is a diagram showing a structure of a sample holding unit including a mounting table.
FIG. 15 is a diagram showing a substrate bias circuit including a susceptor surface.
FIG. 16 is a diagram for explaining the relationship between the thickness of the susceptor and the bias voltage generated on the surface of the susceptor.
FIG. 17 is a diagram for explaining the state of deposit attachment to a thin-walled susceptor.
FIG. 18 is a view for explaining the state of deposit attachment to a thin-walled susceptor.
FIG. 19 is a diagram showing an example in which a metal film is thermally sprayed on the lower surface of the susceptor.
FIG. 20 is a view showing an example in which a metal film is thermally sprayed on the lower surface of the susceptor.
FIG. 21 is a diagram showing an example in which a metal film is embedded in a susceptor.
FIG. 22 is a diagram showing an example in which a metal film is embedded in a susceptor.
FIG. 23 is a diagram showing an example in which a susceptor including a metal film is applied to a ceramic dielectric mounting table.
FIG. 24 is a diagram showing an example in which a susceptor including a metal film is applied to a ceramic dielectric mounting table.
FIG. 25 is a diagram showing a connection structure of bias applying electrodes.
FIG. 26 is a diagram illustrating a means for adjusting a high-frequency bias voltage applied to the susceptor surface.
FIG. 27 is a diagram for explaining an example of the structure of means for adjusting the high-frequency bias voltage applied to the susceptor surface.
FIG. 28 is a diagram illustrating an example in which a high frequency bias is supplied to a susceptor using another power source.
FIG. 29 is a diagram illustrating an example of an electrode structure when a high frequency bias is supplied to a susceptor using another power source.
FIG. 30 is a diagram for explaining a method of optimizing a susceptor bias voltage.
FIG. 31 is a diagram illustrating a susceptor bias application circuit with a feedback circuit.
FIG. 32 is a diagram illustrating a susceptor bias application circuit with a feedback circuit.
FIG. 33 is a diagram illustrating each region in the vacuum processing chamber.
[Explanation of symbols]
1a Upper antenna
1b Lower antenna
2 Vacuum processing chamber
3, 32, 32a Matching box (matching unit)
4 Gas ring
4a Gas supply pipe
5 mounting table
6 Plasma
7 Exhaust device
8 Faraday Shield
9 Sample holder
10 High frequency power supply (first high frequency power supply)
11 Substrate bias power supply (second high frequency power supply)
11a Susceptor bias power supply
12 Berja
12a Elastic conductor
13 samples
14 Slit
15 Filter
16 Detector
17 Amplifier
18 comparator
19 Motor controller
20 Main unit controller
21 Suppress Berja
22 Protection plate
23 Gas outlet
24 Flange
31 Power supply for electrostatic adsorption
33 capacitors
34 Susceptor
35 Insulation base
36 Grounding base
37 Insulation cover
38 Thermal spray coating
39 Metal sprayed film
40 Electrostatic chucking and high frequency bias application electrode
41, 42, 43 Buttocks conductive pattern
50 Ceramic coating
51 susceptor metal sprayed film
52 Attenuators and filters
53 Detector
54 Amplifier
55 comparator
57 Main unit controller
VC1, VC2, VC3 variable capacitor

Claims (6)

A gas ring that constitutes a part of the vacuum processing chamber and has a processing gas outlet;
A mounting table disposed in the vacuum processing chamber and mounting a sample on an upper surface thereof ; a bell jar disposed above the gas ring to form an upper portion of the vacuum processing chamber and covering the plasma generation space above the mounting table;
A coiled antenna that is disposed on the outer periphery of the bell jar and supplies a high frequency electric field for generating plasma in the plasma generation space in the vacuum processing chamber, and a Faraday that is disposed between the antenna and the bell jar and to which a high frequency bias voltage is applied. A shield,
A deposition plate that is detachably disposed on the vacuum processing chamber side of the processing gas outlet and has an opening for allowing the processing gas flowing out of the processing gas outlet to flow therethrough,
The gas ring is arranged so as to be positioned above the mounting table, and the opening of the deposition preventing plate is located outside the prospective angle with respect to the processing gas blowout port through the opening. Is disposed in the direction of the plasma generation space. In the plasma processing apparatus of claim 1,
The deposition plate is detachably disposed on the inner surface of the bell jar via a gap, and the opening of the deposition plate is disposed so that the gas blowing port does not directly face the sample directly through the opening. Processing equipment. The plasma processing apparatus according to claim 1 or 2,
The gas ring is arranged below the bottom of the lower end of the bell jar, the lower end of the inner wall of the bell jar is longer than the lower end of the Faraday shield, and the processing gas passes through the opening from the outlet. Is a plasma processing apparatus. In the plasma processing apparatus in any one of Claims 1 thru | or 3,
The Faraday shield is a plasma processing apparatus in contact with an outer surface of a bell jar through a conductive elastic body. The plasma processing apparatus according to any one of claims 1 to 4,
A plasma processing apparatus, wherein a high frequency power source for supplying a high frequency voltage to the Faraday shield includes a feedback control circuit for controlling the high frequency voltage to a predetermined value. The plasma processing apparatus according to any one of claims 1 to 5,
The plasma processing apparatus which set the area below the said bell jar including the said adhesion prevention plate which can be seen from the surface of the said sample to 1/2 or more of the area of the said sample.

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