JP7515423B2 - Method for detecting abnormality in plasma processing apparatus and plasma processing apparatus - Google Patents

Description

This disclosure relates to a method for detecting abnormalities in a plasma processing device and to a plasma processing device.

Patent document 1 discloses a plasma processing device that, when excessive reflected waves are generated in at least one high-frequency power source, stops the output of that high-frequency power source and instantly stops the output of other high-frequency power sources.

JP 2009-070844 A

This disclosure provides a technology for detecting abnormalities that occur in a plasma processing device.

According to one aspect of the present disclosure, a method for detecting an abnormality in a plasma processing apparatus is provided, the method including: a plurality of antenna coils arranged along a virtual rectangular plane corresponding to a rectangular planar window member that faces the mounting surface of a mounting table on which a substrate is placed inside a processing chamber for processing the substrate and divides the inside of the processing chamber into an upper portion and a lower portion; one end of each of the plurality of antenna coils is connected to a high frequency power source and the other end is connected to a ground potential via an ammeter; at least a portion of the virtual rectangular plane is divided into a plurality of areas in which one of the plurality of antenna coils is arranged; and the virtual rectangular plane has a portion divided into a plurality of integrated areas that combine the areas arranged at symmetrical positions on the virtual rectangular plane; the method includes a step of measuring a change in current over time in each of the plurality of antenna coils with the ammeter; a step of calculating an evaluation value based on the change in current over time for each of the plurality of antenna coils; and a step of calculating a difference between a maximum value and a minimum value of the evaluation value of the antenna coils arranged in each of the areas included in each of the plurality of integrated areas and detecting an abnormality based on the difference.

This disclosure makes it possible to detect abnormalities that occur in plasma processing equipment.

FIG. 1 is a plan view showing an example of a substrate processing system 500 according to the present embodiment. FIG. 2 is a cross-sectional view showing the inductively coupled plasma processing apparatus 100 according to the present embodiment. FIG. 3 is a diagram showing an example of the antenna segment 121. As shown in FIG. FIG. 4 is a diagram showing an example of the area and integrated area of the high frequency antenna 120. As shown in FIG. FIG. 5 is a block diagram showing an example of the antenna circuit 150 of the inductively coupled plasma processing apparatus 100 according to the present embodiment. FIG. 6 is a block diagram showing an example of processing performed by the inductively coupled plasma processing apparatus 100 according to this embodiment. FIG. 7 is a diagram illustrating an example of processing performed by the inductively coupled plasma processing apparatus 100 according to this embodiment. FIG. 8 is a diagram showing an example of processing performed by the inductively coupled plasma processing apparatus 100 according to this embodiment. FIG. 9 is a diagram showing an example of processing performed by the inductively coupled plasma processing apparatus 100 according to this embodiment. FIG. 10 is a plan view showing an example of a spiral antenna according to another embodiment.

<Embodiment>
Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. In this specification and the drawings, substantially identical components are denoted by the same reference numerals, and redundant description may be omitted.

<Substrate Processing System According to an Embodiment>
1 is a plan view showing an example of a substrate processing system 500 according to this embodiment. The substrate processing system 500 includes an inductively coupled plasma (ICP) processing apparatus according to this embodiment.

The substrate processing system 500 is, for example, a system that performs various substrate processing operations on a substrate G that is rectangular in plan view for a flat panel display (FPD). For example, the substrate G is a transparent glass plate or a transparent synthetic resin plate. On the surface of the substrate G, light-emitting elements and electronic circuits including TFTs (Thin Film Transistors) for driving the light-emitting elements are formed.

The substrate processing performed by the substrate processing system 500 includes plasma processing (plasma processes) such as dry etching (plasma etching), plasma CVD (Chemical Vapor Deposition) processing, or plasma PVD (Physical Vapor Deposition) processing. The substrate processing may also include processes that do not use plasma, such as post-processing.

Examples of FPDs include a liquid crystal display (LCD), an organic electroluminescence (EL) panel, or a plasma display panel (PDP).

The planar size of the substrate G for FPDs is becoming larger with each generation. The planar size of the substrate G processed by the substrate processing system 500 may be, for example, at least 1500 mm x 1800 mm for the sixth generation to 3000 mm x 3400 mm for the 10.5th generation. As an example, the thickness of the substrate G is about 0.2 mm to several mm. Multiple FPDs are obtained by singulating one substrate G.

When performing plasma processing on a substrate G for an FPD having a large planar size, which is processed by the substrate processing system 500, uniformity of the plasma density is required over a large area according to the planar size of the substrate G.

The substrate processing system 500 is a cluster tool and is of a multi-chamber type. Furthermore, the substrate processing system 500 is configured as a system capable of performing serial processing in a vacuum atmosphere.

In the substrate processing system 500, a load lock chamber 510 is attached to one side of a centrally located transfer device 520 (which has a transfer chamber and is also called a transfer module) that is hexagonal in plan view. The load lock chamber 510 is attached via a gate valve 512 to the other five sides of the transfer device 520. The five process chambers 530A, 530B, 530C, 530D, and 530E are attached via gate valves 522 to the other five sides of the transfer device 520. The transfer device 520 is not limited to a hexagonal shape in plan view, and may be a rectangle or a polygon with other numbers of strokes in plan view.

Each chamber is controlled to have the same degree of vacuum atmosphere, and is adjusted so that there is no pressure fluctuation between the chambers when the gate valve 522 is opened to transfer the substrate G between the transfer chamber of the transfer device 520 and each of the process chambers 530A to 530E.

A loader module (not shown) is connected to the load lock chamber 510 via a gate valve 511. The load lock chamber 510 is adjacent to the loader module. The loader module contains a large number of substrates G in a cassette (not shown) that is arranged at a location separate from the connection point with the load lock chamber 510. The load lock chamber 510 is configured to be able to switch the internal pressure atmosphere between a normal pressure atmosphere and a vacuum atmosphere. The load lock chamber 510 transfers the substrates G to and from the loader module.

The load lock chambers 510 are stacked, for example, in two stages. Inside each load lock chamber 510, a rack 514 for holding the substrate G and a positioner 513 for adjusting the position of the substrate G are provided. After the load lock chamber 510 is controlled to a vacuum atmosphere, the gate valve 512 opens to communicate with the transfer device 520, which is also controlled to a vacuum atmosphere, and the substrate G is transferred from the load lock chamber 510 to the transfer device 520 in the direction of arrow D2.

The transport device 520 is equipped with a transport mechanism 521 that can rotate in the direction of the arrow D1 and slide toward each of the process chambers 530A-530E. The direction of the arrow D1 is the circumferential direction. The transport mechanism 521 transports the substrate G transferred from the load lock chamber 510 to the desired process chamber (one of the process chambers 530A-530E). In addition, the transport mechanism 521 transfers the substrate G to each of the process chambers 530A-530E, which are adjusted to the same vacuum atmosphere as the transport device 520, by opening the gate valve 522.

Between the transfer device 520 and process chamber 530A, the substrate G is transferred in the direction of arrow D3. Similarly, between the transfer device 520 and process chamber 530B, the substrate G is transferred in the direction of arrow D4. Between the transfer device 520 and process chamber 530C, the substrate G is transferred in the direction of arrow D5. Between the transfer device 520 and process chamber 530D, the substrate G is transferred in the direction of arrow D6. Between the transfer device 520 and process chamber 530E, the substrate G is transferred in the direction of arrow D7. The substrate G is transferred to the process chambers 530A to 530E according to the process recipe, where plasma processing, etc. is performed.

One or more of the process chambers 530A-530E may be a chamber for performing plasma processing such as dry etching processing (plasma etching processing) using a halogen-based etching gas (e.g., fluorine-based or chlorine-based etching gas), plasma CVD processing, or plasma PVD processing. The process chambers 530A-530E may also include a chamber for performing after-treatment (post-treatment) for removing chlorine or chlorine-based compounds from the substrate G. The portion of the substrate processing system 500 that includes the chamber for performing plasma processing is the inductively coupled plasma processing apparatus of the embodiment.

Of the process chambers 530A-530E, it is important to ensure uniform plasma density in the chambers that perform plasma processing. The planar size of the substrate G is very large, and multiple FPDs can be obtained from a single substrate G. For this reason, if the uniformity of the plasma density is low, the distribution of the film quality formed on the substrate G deteriorates, making it impossible to produce an FPD with good image quality. From this perspective, it is extremely important to increase the uniformity of the plasma density in the plasma processing included in the manufacturing process of the substrate G for FPDs.

Figure 2 is a cross-sectional view showing the inductively coupled plasma processing apparatus 100 according to this embodiment. The inductively coupled plasma processing apparatus 100 includes a process chamber 530. The process chamber 530 is one of the process chambers 530A to 530E shown in Figure 1 that performs plasma processing. Specifically, the plasma processing includes, for example, etching of silicon oxide films, silicon nitride films, metal films, etc., deposition of silicon oxide films or silicon nitride films that protect metal films or ITO (Indium Tin Oxide) films when forming thin film transistors on the surface of the substrate G, or ashing of resist films.

The process chamber 530 is an airtight rectangular cylindrical chamber made of a conductive material, for example, aluminum whose inner wall surface is anodized. The process chamber 530 is assembled so as to be disassembled, and is electrically grounded by a ground wire 1a. The process chamber 530 is divided into an antenna chamber 3 and a process chamber 4 by a dielectric wall (dielectric window) 2. Therefore, the dielectric wall 2 functions as a ceiling wall of the process chamber 4 which divides the process chamber 4 into an upper part and a lower part. The dielectric wall 2 has a rectangular planar shape when viewed from above. The dielectric wall 2 is made of ceramics such as _{Al2O3 ,} quartz, or the like.

A shower housing 11 for supplying process gas is fitted into the lower portion of the dielectric wall 2. The shower housing 11 is provided, for example, in a cross shape. The shower housing 11 functions as a beam that supports the dielectric wall 2 from below. The dielectric wall 2 may be divided into four parts corresponding to the cross-shaped shower housing 11. The shower housing 11 that supports the dielectric wall 2 is suspended from the ceiling of the process chamber 530 by a number of suspenders (not shown).

The shower housing 11 is made of a conductive material, preferably metal. For example, the shower housing 11 is made of aluminum with an anodized inner or outer surface to prevent contamination. The shower housing 11 is electrically grounded.

The shower housing 11 is formed with a gas flow path 12 extending horizontally. A plurality of gas discharge holes 12a extending downward are connected to the gas flow path 12. A gas supply pipe 20a communicating with the gas flow path 12 is provided in the center of the upper surface of the dielectric wall 2. The gas supply pipe 20a extends outward through the ceiling of the process chamber 530 and is connected to a process gas supply system 20 including a process gas supply source and a valve system. Therefore, in plasma processing, the process gas supplied from the process gas supply system 20 is supplied into the shower housing 11 through the gas supply pipe 20a and discharged into the process chamber 4 from the gas discharge holes 12a.

A support shelf 5 that protrudes inward is provided between the side wall 3a of the antenna chamber 3 and the side wall 4a of the processing chamber 4 in the process chamber 530. The dielectric wall 2 is placed on the support shelf 5.

The inductively coupled plasma processing apparatus 100 also includes an antenna unit 50 having a radio frequency (RF) antenna 120. The radio frequency antenna 120 is connected to a radio frequency power source 15 via a power supply 51, a power supply line 19, and a matching device 14. The radio frequency antenna 120 is separated from the dielectric wall 2 by a spacer 17 made of an insulating material. When radio frequency power having a frequency of, for example, 13.56 MHz is supplied to the radio frequency antenna 120 from the radio frequency power source 15, an induced electric field is generated in the processing chamber 4. The processing gas supplied from the shower housing 11 is turned into plasma by the induced electric field generated in the processing chamber 4 by the radio frequency antenna 120.

The antenna unit 50 includes a high-frequency antenna 120 and a power supply section 51 that supplies high-frequency power that has passed through a matching device 14 to the high-frequency antenna 120. The high-frequency antenna 120 is provided on the upper surface of the dielectric wall 2.

The high frequency antenna 120 has multiple antenna segments. As shown in FIG. 3, each antenna segment is formed by winding an antenna wire made of a copper wire or the like. The antenna segments will be described in detail later.

The planar portions of the multiple antenna segments of the high frequency antenna 120 face downward on the upper surface 2A side of the dielectric wall 2, and are arranged to face the upper surface of the substrate G via the dielectric wall 2, which functions as a dielectric window for high frequency power. The planar portions of the multiple antenna segments of the high frequency antenna 120 are arranged to form concentric rectangular rings, and as a whole form a rectangular plane corresponding to the substrate G. The planar portions of the multiple antenna segments of the high frequency antenna 120 as a whole form a rectangular ring, and form a multi-segment annular antenna, for example, with three concentric rings of an outer annular antenna, an intermediate annular antenna, and an inner annular antenna, and generate an induced electric field that contributes to plasma generation.

The process chamber 530 is an example of a processing chamber, the dielectric wall 2 is an example of a window member, and the upper surface 2A of the dielectric wall 2 is an example of a virtual rectangular plane. For example, the process chamber 530 may be divided into the antenna chamber 3 and the processing chamber 4 by a metal wall (metal window) instead of the dielectric wall 2. In this case, the high frequency antenna 120 first induces an induced current in the metal wall, and the induced current induced in the metal wall generates an induced electric field in the processing chamber 4 that contributes to plasma generation. The metal wall may also serve as a shower housing.

The high frequency antenna 120 is divided into multiple areas each containing one or more antenna segments that supply high frequency power to the plasma generated in the process chamber 530 in order to control the plasma density distribution in several regions.

At the bottom of the processing chamber 4, a mounting table 23 for mounting the substrate G is provided so as to face the high frequency antenna 120 across the dielectric wall 2. The substrate G is placed on the mounting surface 23A. The mounting table 23 is made of a conductive material, for example aluminum whose surface has been anodized. The substrate G placed on the mounting table 23 is attracted and held by an electrostatic chuck (not shown).

The mounting table 23 is housed in an insulating frame 24. The mounting table 23 is supported on the bottom of the process chamber 530. The mounting table 23 is provided with lifting pins (not shown). When the substrate G is loaded or unloaded, the lifting pins lift the substrate G up and down. The side wall 4a of the processing chamber 4 is provided with a loading/unloading port 27a for loading and unloading the substrate G and a gate valve 512 for opening and closing the loading/unloading port 27a.

A high-frequency power supply 29 is connected to the mounting table 23 via a power supply line 25a and a matching box 28. During plasma processing, the high-frequency power supply 29 applies high-frequency bias power, for example, high-frequency power with a frequency of 3.2 MHz, to the mounting table 23. The self-bias generated by the high-frequency bias power effectively attracts ions in the plasma generated in the processing chamber 4 to the substrate G.

In addition, a temperature control mechanism including a heating means such as a ceramic heater and a refrigerant flow path, and a temperature sensor are provided within the mounting table 23 to control the temperature of the substrate G (neither is shown). The piping and wiring for these mechanisms and components are led out to the outside of the process chamber 530.

An exhaust device 30 including a vacuum pump and the like is connected to the bottom of the processing chamber 4 via an exhaust pipe 31. The exhaust device 30 evacuates the processing chamber 4, and a predetermined vacuum atmosphere (e.g., 1.33 Pa) is set and maintained within the processing chamber 4 during plasma processing.

To improve the temperature controllability of the substrate G by the temperature control mechanism provided on the mounting table 23, a He gas flow path 41 is provided to supply a heat transfer gas (He gas) at a constant pressure to the minute gap between the upper surface of the mounting table 23 and the rear surface of the substrate G. By supplying the heat transfer gas to the rear surface side of the substrate G in this manner, it is possible to prevent temperature rises and changes in the substrate G under vacuum.

The inductively coupled plasma processing apparatus 100 includes a control device 110. The control device 110 is realized, for example, by a computer. The computer includes a CPU (Central Processing Unit), a RAM (Random Access Memory), a ROM (Read Only Memory), a HDD (Hard Disk Drive), an input/output interface, an internal bus, etc.

The control device 110 has a main control unit 111, a plasma generation processing unit 112, an abnormality detection and judgment unit 113, and a memory 115. The main control unit 111, the plasma generation processing unit 112, and the abnormality detection and judgment unit 113 are functional blocks that represent the functions of the programs executed by the control device 110. The memory 115 is a functional representation of the memory of the control device 110.

Each component of the inductively coupled plasma processing apparatus 100 is connected to a control device 110. Each component of the inductively coupled plasma processing apparatus 100 is controlled by a main control unit 111, a plasma generation processing unit 112, and an abnormality detection and judgment unit 113 of the control device 110.

The control device 110 is also connected to a user interface 101 including a keyboard through which an operator performs input operations such as inputting commands to manage the inductively coupled plasma processing device 100, and a display that visualizes and displays the operating status of the inductively coupled plasma processing device 100.

The operator is not limited to a worker at a factory where the inductively coupled plasma processing device 100 is delivered, but also includes a worker who operates the inductively coupled plasma processing device 100 during the assembly stage before shipment at a manufacturing factory for the inductively coupled plasma processing device 100.

The main control unit 111 is a processing unit that manages the control processing of the control device 110, and executes processing other than that performed by the plasma generation processing unit 112 and the anomaly detection and determination unit 113. For example, the main control unit 111 controls the transport of the substrate G and controls etching processing and film formation processing according to a process recipe.

The plasma generation processing unit 112 performs a plasma generation process that generates plasma by supplying high-frequency power to multiple areas of the high-frequency antenna 120. The plasma generation processing unit 112 also adjusts the output of the high-frequency power output by the power supply unit 51.

The abnormality detection and determination unit 113 detects abnormalities in the inductively coupled plasma processing apparatus 100. Details of the abnormality detection and determination unit 113 will be described later.

The memory 115 stores (contains) control programs for implementing various processes performed by the inductively coupled plasma processing apparatus 100, and programs (process recipes) for causing each component of the inductively coupled plasma processing apparatus 100 to execute processes according to processing conditions. The process recipe may be transmitted to the control apparatus 110 from a portable storage medium such as a CD-ROM, DVD, or flash memory and stored in the memory 115. Alternatively, the process recipe may be transmitted to the control apparatus 110 from another apparatus, for example, via a dedicated line. Then, as necessary, an arbitrary process recipe is called from the memory 115 in response to an instruction from the user interface 101, and executed by the control apparatus 110, whereby the desired plasma processing, etc., is performed in the inductively coupled plasma processing apparatus 100 under the control of the control apparatus 110.

In addition, data representing the relationship between the multiple areas and the multiple integrated areas described below and the antenna segments is stored in memory 115.

The control device 110 is also connected to an external host computer 200. The host computer 200 acquires the processing results and device status data of the inductively coupled plasma processing device 100 from the control device 110.

The processing in the control device 110 may be performed by multiple devices. A part of the processing in the control device 110, for example, the processing of the anomaly detection and determination unit 113, may be processed by a programmable logic controller or the like.

Figure 3 is a diagram showing an example of an antenna segment 121. The antenna segment 121 is one of a plurality of antenna segments 121 that the high frequency antenna 120 has. Figure 3 shows an XYZ coordinate system. The XY plane is parallel to the horizontal plane, and the Z direction is the vertical upward direction.

The antenna segment 121 is, for example, an antenna wire 122 made of a conductive material such as copper wound three-dimensionally multiple times in the up-down direction around a winding axis RA that extends in the horizontal direction. The winding axis RA is, for example, parallel to the X-axis. The antenna wire 122 is not wound in a horizontal plane, but is bent and wound in the up-down direction (vertical direction). The antenna wire 122 is wound vertically in a rectangular shape when viewed in the YZ plane.

The antenna wire 122 has multiple bottoms 122C because it is wound multiple times between the end 122A and the end 122B. The bottoms 122C are the parts located at the bottom of the antenna wire 122 that is wound three-dimensionally. The multiple bottoms 122C are, as an example, parallel to the Y axis and form a planar portion 125 that is parallel to the horizontal plane.

The antenna wire 122 shown in FIG. 3 has three bottom portions 122C, for example, and therefore the flat portion 125 is formed by three bottom portions 122C, for example. The induced electric field generated by the flat portion 125 contributes to the generation of plasma.

The shape of the antenna segment 121 shown in FIG. 3 is an example, and the shapes of the multiple antenna segments 121 that the high frequency antenna 120 has are adapted to the shape of each area, etc. Therefore, depending on the location of each area, the shape of the antenna segment 121 may differ from the shape of the antenna segment 121 shown in FIG. 3, but all antenna segments 121 have a planar portion 125 composed of multiple bottom portions 122C. The planar portion 125 is arranged along the upper surface 2A of the dielectric wall 2.

Antenna segment 121 is an example of an antenna coil.

Figure 4 is a diagram showing an example of area A and integrated area SA of the radio frequency antenna 120. The antenna unit 50 is divided into 18 areas, area A1 to area A18. Each of areas A1 to A18 includes an antenna segment 121. Areas A1 and A2 constitute an inner area corresponding to the inner annular antenna, areas A3 to A6 constitute an intermediate area corresponding to the intermediate annular antenna, and areas A7 to A18 constitute an outer area corresponding to the outer annular antenna. The inner area, intermediate area, and outer area are examples of multiple concentric rectangular areas. The outer area is located on the outermost periphery of the multiple concentric rectangular areas.

In addition, each of areas A1 to A18 belongs to one of integrated areas SA1 to SA5. The areas included in each of integrated areas SA1 to SA5 are composed of a combination of areas that are point-symmetric or line-symmetric when viewed from above the mounting table 23.

For example, areas that are point-symmetric with respect to the surface center AC of the mounting table 23 (mounting surface 23A) may be combined. Areas that are line-symmetric with respect to an axis AX that passes through the surface center AC of the mounting table 23 (mounting surface 23A) and is perpendicular to the short side of the mounting table 23 (mounting surface 23A) or an axis AY that passes through the surface center AC of the mounting table 23 (mounting surface 23A) and is perpendicular to the long side of the mounting table 23 (mounting surface 23A) may be combined. Furthermore, areas that are line-symmetric with respect to the diagonal of the mounting table 23 (mounting surface 23A) may be combined.

The antenna segment 121 arranged on the upper surface 2A of the dielectric wall 2 is arranged point-symmetrically with respect to a center corresponding to the surface center AC of the mounting base 23 (mounting surface 23A) on the upper surface 2A of the dielectric wall 2. For example, the winding axis RA of the antenna segment 121 faces in the central direction corresponding to the surface center AC of the mounting base 23 (mounting surface 23A) on the upper surface 2A of the dielectric wall 2 or in a direction parallel to the central direction.

Therefore, the antenna segments 121 placed in areas that are symmetrically positioned have the same antenna current due to their structure. In this embodiment, areas in which antenna segments 121 with the same characteristics are placed are integrated into an integrated area. Then, abnormalities can be detected stably by making judgments based on the antenna currents in the antenna segments 121 of the integrated area.

Note that axis AX is an example of a first axis of symmetry, and axis AY is an example of a second axis of symmetry.

Specifically, we will explain the areas included in each of integrated areas SA1 to SA5.

The integrated area SA1 includes areas A1 and A2. Areas A1 and A2 are point-symmetric with respect to the surface center AC of the mounting table 23. Areas A1 and A2 are also line-symmetric with respect to the axis AX of the mounting table 23.

Integrated area SA2 includes areas A3, A4, A5, and A6. Areas A3 and A5 are point-symmetric with respect to the center of mounting table 23. Areas A4 and A6 are point-symmetric with respect to the center of mounting table 23. Note that areas A3 and A5A are on the short side, and areas A4 and A6 are on the long side, so these areas on the short side and the long side are not strictly the same shape, but depending on the required accuracy of judgment, areas A3, A4, A5, and A6 may all be treated as point-symmetric with respect to the center of mounting table 23.

The integrated area SA3 includes the integrated area SA3a and the integrated area SA3b. The integrated area SA3a and the integrated area SA3b are each a collection of areas that are adjacent to each other within the integrated area SA3 and can be viewed as a single unit. In other words, the integrated area SA3 is divided into groups of areas that are spaced apart from each other (the same applies below). The integrated area SA3a includes the area A7 and the area A8. The integrated area SA3b includes the area A9 and the area A10. The areas A7 and A10 included in the integrated area SA3 are point-symmetric with respect to the center of the mounting table 23. The areas A8 and A9 included in the integrated area SA3 are point-symmetric with respect to the center of the mounting table 23. Furthermore, for example, the areas A7 and A9 are each line-symmetric with respect to the axis AX. Furthermore, for example, the areas A7 and A8 are each line-symmetric with respect to the axis AY.

The integrated area SA4 includes the integrated area SA4a and the integrated area SA4b. The integrated area SA4a includes the area A11 and the area A12. The integrated area SA4b includes the area A13 and the area A14. The areas A11 and A14 included in the integrated area SA4 are point-symmetric with respect to the center of the mounting table 23. The areas A12 and A13 included in the integrated area SA4 are point-symmetric with respect to the center of the mounting table 23. Furthermore, for example, the areas A11 and A12 are each line-symmetric with respect to the axis AX. Furthermore, for example, the areas A11 and A13 are each line-symmetric with respect to the axis AY.

The integrated area SA5 includes integrated areas SA5a, SA5b, SA5c, and SA5d. Integrated area SA5a is equal to area A15. Integrated area SA5b is equal to area A16. Integrated area SA5c is equal to area A17. Integrated area SA5d is equal to area A18. Areas A15 and A17 included in integrated area SA5 are point-symmetric with respect to the center of the mounting table 23. Areas A16 and A18 included in integrated area SA5 are point-symmetric with respect to the center of the mounting table 23. Furthermore, for example, areas A15 and A16 are each line-symmetric with respect to axis AX. Furthermore, for example, areas A15 and A18 are each line-symmetric with respect to axis AY. As with the integrated area SA2, depending on the required accuracy of the determination, areas A15, A16, A17, and A18 may all be treated as being point symmetric with respect to the center of the mounting table 23.

In the specific example of the integrated areas described above, integrated area SA1 constitutes the inner area, integrated area SA2 constitutes the middle area, and integrated areas SA3, SA4, and SA5 constitute the outer area.

Figure 5 is a block diagram showing an example of an antenna circuit 150 of the inductively coupled plasma processing apparatus 100 according to this embodiment.

The antenna circuit 150 includes a plurality of antenna segments 121 corresponding to each of areas A1 to A18. The antenna circuit 150 includes a plurality of ammeters 131 that measure the antenna current and are provided between each of the antenna segments 121 and the ground. That is, one end of the antenna segment 121 is connected to the high-frequency power supply 15, and the other end is connected to the ground potential via the ammeter 131.

The ammeter 131 is, for example, a current transformer. The ammeter 131 outputs, for example, a voltage based on the current flowing between the antenna segment 121 and ground.

Figure 6 is a block diagram showing an example of processing by the inductively coupled plasma processing apparatus 100 according to this embodiment.

The inductively coupled plasma processing apparatus 100 includes ammeters 131 corresponding to areas A1 to A18, input units 132 connected to the ammeters 131, and anomaly detection and determination unit 113 that detects and determines anomalies. Furthermore, the anomaly detection and determination unit 113 outputs the detected results to the host computer 200.

Each of the ammeters 131 corresponding to each of areas A1 to A18 is connected to an acquisition unit 132. The acquisition unit 132 is, for example, an A/D (Analog/Digital) converter that performs analog-to-digital conversion of an analog signal corresponding to the current value measured by each of the ammeters 131 into a digital signal.

The abnormality detection and determination unit 113 determines whether an abnormality has occurred in each of the integrated areas SA1 to SA5. The abnormality detection and determination unit 113 determines whether an abnormality has occurred based on the current values measured in areas A1 to A18 included in any of the integrated areas SA1 to SA5.

The abnormality detection process in the abnormality detection and determination unit 113 will be described. By describing the abnormality detection process in the abnormality detection and determination unit 113, the abnormality detection method of the inductively coupled plasma processing apparatus 100 will be described. Figure 7 is a flowchart showing an example of the process of the inductively coupled plasma processing apparatus 100 according to this embodiment.

The plasma generation processing unit 112 supplies rated high-frequency power from the high-frequency power supply 15 to the high-frequency antenna 120 (step S10). Then, the abnormality detection and determination unit 113 starts the abnormality detection process (step S20). The abnormality detection and determination unit 113 captures the change over time in the antenna current measured by the ammeter 131 in each of areas A1 to A18. That is, the abnormality detection and determination unit 113 measures the change over time in the current of each coil antenna (antenna segment 121) in areas A1 to A18 with the ammeter 131. Then, the abnormality detection and determination unit 113 generates the measurement results as sampling data (step S30).

Step S30 is an example of a process in which the current change over time of each of the multiple antenna coils (antenna segments 121) is measured using the ammeter 131.

The abnormality detection and determination unit 113 calculates the current change rate in each of areas A1 to A18 (step S40).

Here, to explain the processing in any of areas A1 to A18, each of areas A1 to A18 will be explained as area An (where n is an integer between 1 and 18).

The measurement value of the ammeter 131 in area An at time t is denoted as CT_n(t). The time rate of change of the antenna current is calculated based on the current value of the antenna current measured at one or more time intervals. For example, when measuring the time rate of change of the antenna current for K time intervals (where K is an integer equal to or greater than 1), the K time intervals are represented as time interval Δt_k. Note that k is an integer equal to or greater than 1 and equal to or less than K, for example, 10. Note that it is preferable that the time interval Δt_k is an integer multiple of the sampling period in the acquisition unit 132.

By obtaining the measurement value of the ammeter 131 in area An at time intervals Δt_k, the current value of the antenna current can be measured at time intervals. Furthermore, by measuring at multiple time intervals Δt_k, this method can also be applied when the antenna current has a time-varying background. For example, by measuring at multiple time intervals Δt_k, it is also possible to handle cases where the antenna current changes slowly or quickly.

For example, time interval Δt_k may be such that time interval Δt_1 is the sampling period in capture unit 132, time interval Δt_2 is twice the sampling period in capture unit 132, and time interval Δt_3 is four times the sampling period in capture unit 132.

The anomaly detection and determination unit 113 calculates the time rate of change of the antenna current as an evaluation value based on the change over time of the antenna current in the antenna coil. The time rate of change of the antenna current in area An at time t and time interval Δt_k is defined as the time rate of change ΔCT_n,k(t). The anomaly detection and determination unit 113 calculates the time rate of change ΔCT_n,k(t) using Equation 1.

ΔCT_n, k(t) = (CT_n(t) - CT_n(t - Δt_k)) / CT_n(t) ... (Equation 1)

When detecting anomalies at multiple time intervals, the anomaly detection determination unit 113 calculates multiple time change rates ΔCT_n,k(t) for multiple different time intervals Δt_k.

In addition, in formula 1, CT_n(t) is an example of a first current value, CT_n(t-Δt_k) is an example of a second current value, and CT_n(t)-CT_n(t-Δt_k) is an example of the amount of change between the first current value and the second current value. In formula 1, the amount of change between the first current value and the second current value is divided by the first current value, but it may be divided by the second current value. Furthermore, step S40 is an example of a process for calculating an evaluation value based on the change in current over time for each of the multiple antenna coils (antenna segments 121).

Next, the anomaly detection and determination unit 113 calculates the time change rate difference of the antenna current for each time interval Δt_k in each of the integrated areas SA1 to SA5 (step S45). Here, to explain the processing in any of the integrated areas SA1 to SA5, each of the integrated areas SA1 to SA5 will be explained as an integrated area SAm (where m is an integer between 1 and 5).

The abnormality detection determination unit 113 compares the time change rates of the antenna currents of the areas included in the integrated area SAm, and calculates the time change rate difference ΔSA_m,k(t) of the antenna currents in the integrated area SAm at time t and time interval Δt_k using Equation 2. Note that n indicates the number of the area included in the integrated area SAm. Also, max(ΔCT_n,k(t)) indicates the largest value (maximum value) among the time change rates ΔCT_n,k(t) of the areas included in the integrated area SAm. Min(ΔCT_n,k(t)) indicates the smallest value (minimum value) among the time change rates ΔCT_n,k(t) of the areas included in the integrated area SAm. Note that the n in max(ΔCT_n, k(t)) and the n in min(ΔCT_n, k(t)) indicate different area numbers, but for convenience, we will use the same n here and represent them as the area number with the maximum value and the area number with the minimum value, respectively.

ΔSA_m,k(t) = max(ΔCT_n,k(t)) - min(ΔCT_n,k(t)) ... (Equation 2)

By processing in step S40, the anomaly detection and determination unit 113 calculates the time change rate difference ΔSA_m,k(t) of M (here, five) antenna currents for each time interval Δt_k.

Step S45 is an example of a process for calculating the difference between the maximum and minimum evaluation values of the antenna coils (antenna segments 121) placed in each of the areas included in each of the multiple integrated areas, and detecting an abnormality based on the difference.

Then, the anomaly detection determination unit 113 determines whether all of the time change rate differences ΔSA_m,k(t) of the M antenna currents are less than a threshold value (step S50). Note that the threshold value is a predetermined reference difference value (reference difference value).

If all of the M antenna current time change rate differences ΔSA_m,k(t) are less than the threshold value (Yes in step S50), the abnormality detection and determination unit 113 determines that the antenna current is normal. Then, the abnormality detection and determination unit 113 determines whether to end the process (step S60).

If the process is not to be terminated, i.e., if the process is to be continued (No in step S60), the process returns to step S30 and is repeated. If the process is to be terminated (Yes in step S60), the process is terminated.

If at least one of the time change rate differences ΔSA_m,k(t) of the M antenna currents is not less than the threshold, i.e., exceeds the threshold (No in step S50), the anomaly detection and determination unit 113 determines that there is a possibility of an anomaly and determines that there is a provisional anomaly. The anomaly detection and determination unit 113 counts the number of times that it has determined that there is a provisional anomaly. Then, the anomaly detection and determination unit 113 determines whether the number of times that it has determined that there is a provisional anomaly is equal to or greater than a set number (step S70).

If the number of times that a provisional abnormality is determined (the number of times that the reference difference value is exceeded (the number of times that it is exceeded)) is equal to or greater than the set number (reference number) (Yes in step S70), the abnormality detection determination unit 113 detects that an abnormality has occurred (step S80). Then, the plasma generation processing unit 112 determines that an abnormality has occurred and stops the supply of high-frequency power from the high-frequency power source 15 to the high-frequency antenna 120. Then, the main control unit 111 performs an abnormality shutdown of the inductively coupled plasma processing device 100 (step S90).

Step S90 is an example of a process for stopping the high-frequency power supply.

If the number of times that a provisional abnormality has been determined is less than the set number of times (No in step S70), the abnormality detection determination unit 113 returns to step S30 and continues the measurement again. The above process is performed for each of the K time intervals.

A specific example of processing is shown in FIG. 8. FIG. 8 is a diagram for explaining processing of the inductively coupled plasma processing apparatus 100 according to this embodiment. In FIG. 8, processing in the integrated area SA5 is explained. In FIG. 8, one time interval Δt is explained. Note that the waveform in FIG. 8 is a simulated waveform created for explanatory purposes.

The horizontal axis of FIG. 8 represents time. The vertical axis of FIG. 8 represents values equivalent to the current value. Graph Frf in FIG. 8 represents the current value supplied from high frequency power supply 15. Graphs F1, F2, F3, and F4 represent the current measurement values of areas A15, A16, A17, and A18, respectively. Graph Fv represents the time change rate difference of the antenna current. Fth represents the threshold value of the difference value (reference difference value). In addition, the reference number of times, which is the threshold value of the number of times, is set to 5 times.

The current value at time T2 in area A15 shown in graph F1 fluctuates relative to the current value at time T1. On the other hand, graphs F2, F3, and F4 at time T2 do not fluctuate relative to time T1. Because there was a change in the current value in area A15, graph Fv, which is the time rate of change difference of the antenna current, is larger at time T2 relative to time T1. However, since at time T2 it is smaller than the threshold value, graph Fth, no abnormality is detected.

At time T4, graph Fv is greater than graph Fth, so it is determined to be a provisional abnormality. However, since the number of occurrences is 1, compared to the threshold number of occurrences (reference number of occurrences) of 5, processing continues as is. Note that the numbers shown on the graph indicate the number of times the reference difference value was exceeded (number of times exceeded).

Similarly, tentative abnormalities are detected at time T5, time T8, time T11, and time T12. At time T12, the number of times is equal to the reference number of times, which is five. Therefore, after it is determined at time T12 that the reference number of times has been reached, the current supplied from the high-frequency power supply 15 is stopped.

Specifically, the results of operation using the inductively coupled plasma processing apparatus 100 will be described. Figure 9 is a diagram showing an example of processing when the inductively coupled plasma processing apparatus 100 according to this embodiment is operated.

Figure 9(a) shows the time waveform of the current value measured by the inductively coupled plasma processing device 100. The horizontal axis of Figure 9(a) represents time. The vertical axis of Figure 9(a) represents the current value. Graph Grf in Figure 9(a) represents the current value supplied from the high frequency power supply 15. Graph G represents the current measurement values of areas A15, A16, A17, and A18, respectively.

Figure 9(b) shows the time change rate difference calculated by the inductively coupled plasma processing apparatus 100. The horizontal axis of Figure 9(b) represents time. Note that the time on the horizontal axis of Figure 9(b) corresponds to the time on the horizontal axis of Figure 9(a). The vertical axis of Figure 9(b) represents the time change rate difference. Graph Gv in Figure 9(b) represents the time change rate difference of the antenna current. Gth represents the threshold value.

In FIG. 9(b), an abnormality is detected at the point indicated by P. When an abnormality is detected five times, the current supplied from the high-frequency power supply 15 is stopped.

<Other embodiments>
In the above embodiment, an example was shown in which the annular antennas in the outer area, middle area, and inner area are configured with antenna segments using vertically wound antenna coils such as the antenna segment 121 shown as an example in FIG. 3. In contrast to this, in another embodiment, only the outer annular antenna in the outer area may be configured with an antenna segment using a vertically wound antenna coil. In this case, an annular antenna configured with a spiral antenna 160 as shown in FIG. 10 may be arranged in the middle area and inner area. The spiral antenna 160 in FIG. 10 is configured by winding four antenna wires 161 with a 90° offset each other, but is not limited to this. For example, two antenna wires may be wound with a 180° offset, or one antenna wire may be wound, as long as it is configured to have a spiral shape as a whole. In this other embodiment, an abnormality detection process is performed on an antenna segment basis in the outer area, and an abnormality is detected for the spiral antenna alone in the middle area and inner area. When an abnormality detection process is performed only in the outer area, the device configuration becomes simpler and costs can be reduced, so this embodiment has the advantage of being used when it is sufficient to perform an abnormality detection process in the outer edge of the plasma. Also, a configuration may be used in which an antenna segment of a vertically wound antenna coil is used for the outer area and the middle area, and a spiral antenna 160 is arranged in the inner area. Also, a configuration may be used in which a spiral antenna 160 is arranged in the outer area, and an antenna segment of a vertically wound antenna coil is arranged in the middle area or the inner area, or both. In other words, a configuration can be used in which an abnormality detection process can be performed specifically in the part of the plasma to be monitored.

The above describes the embodiments of the anomaly detection method and inductively coupled plasma processing apparatus according to the present disclosure, but the present disclosure is not limited to the above-mentioned embodiments. Various changes, modifications, substitutions, additions, deletions, and combinations are possible within the scope of the claims. Naturally, these also fall within the technical scope of the present disclosure.

1a Ground wire 2 Dielectric wall (dielectric window)
3 Antenna chamber 3a Side wall 4 Processing chamber 4a Side wall 5 Support shelf 11 Shower housing 12 Gas flow path 14 Matching box 15 High frequency power source 17 Spacer 19 Power supply line 20 Processing gas supply system 23 Mounting table 24 Insulator frame 29 High frequency power source 30 Exhaust device 31 Exhaust pipe 41 He gas flow path 50 Antenna unit 51 Power supply unit 100 Inductively coupled plasma processing apparatus 101 User interface 110 Control device 111 Main control unit 112 Plasma generation processing unit 113 Anomaly detection and judgment unit 115 Memory 120 High frequency (RF: Radio Frequency) antenna 121 Antenna segment 131 Ammeter 132 Take-in unit 150 Antenna circuit 500 Substrate processing system 510 Load lock chamber 520 Transport device 521 Transport mechanism 530, 530A, 530B, 530C, 530D, 530E Process chambers A1 to A18 Area G Substrates SA, SA1, SA2, SA3, SA4, SA5 Integrated area

Claims (12)

a plurality of antenna coils disposed along an imaginary rectangular plane corresponding to a rectangular planar window member that divides the interior of a processing chamber into an upper portion and a lower portion, the antenna coils facing a mounting surface of a mounting table on which a substrate is mounted within the processing chamber for processing a substrate, the window member having a rectangular planar shape,
Each of the plurality of antenna coils has one end connected to a high frequency power source and the other end connected to a ground potential via an ammeter;
the imaginary rectangular plane is at least partially partitioned into a plurality of areas in which any one of the plurality of antenna coils is disposed;
a virtual rectangular plane having a portion partitioned into a plurality of integrated areas each of which is a combination of the areas disposed at symmetrical positions on the virtual rectangular plane, the method comprising:
measuring a change over time in current of each of the plurality of antenna coils with the ammeter;
calculating an evaluation value based on a change in current over time for each of the plurality of antenna coils;
and calculating a difference between a maximum value and a minimum value of the evaluation value of the antenna coil disposed in each of the areas included in each of the plurality of integrated areas, and detecting an abnormality based on the difference.
Method for detecting abnormality in plasma processing apparatus. The virtual rectangular plane is divided into a plurality of concentric rectangular areas, and the plurality of integrated areas are defined at least in an outer area located at the outermost periphery of the plurality of concentric rectangular areas.
The method for detecting an abnormality in a plasma processing apparatus according to claim 1 . The plurality of integrated areas are defined in all of the plurality of concentric rectangular areas.
The method for detecting an abnormality in a plasma processing apparatus according to claim 2. comparing the difference with a predetermined reference difference value, and stopping the high frequency power supply when the difference exceeds the reference difference value in the change over time.
The method for detecting an abnormality in a plasma processing apparatus according to claim 1 . In the step of stopping the high frequency power supply, the number of times that the difference exceeds the reference difference value in the change over time is counted, and when the number of times that the difference exceeds the reference difference value reaches a predetermined number of times, the high frequency power supply is stopped.
The method for detecting an abnormality in a plasma processing apparatus according to claim 4. The symmetry is about at least any one of a face center of the virtual rectangular plane, a first symmetry axis passing through the face center and perpendicular to a short side of the virtual rectangular plane, a second symmetry axis passing through the face center and perpendicular to a long side of the virtual rectangular plane, and a diagonal line of the virtual rectangular plane.
The method for detecting an abnormality in a plasma processing apparatus according to any one of claims 1 to 5. the evaluation value is a current change rate obtained by dividing an amount of change between a first current value and a second current value in the change in the current over time by the first current value or the second current value;
The method for detecting an abnormality in a plasma processing apparatus according to any one of claims 1 to 6. The first current value and the second current value are values of the current measured at time points separated by a predetermined time.
The method for detecting an abnormality in a plasma processing apparatus according to claim 7. In the step of calculating the evaluation value, a plurality of evaluation values are calculated based on the change over time of the current at a plurality of different time intervals;
In the step of detecting an anomaly, the difference is calculated for each of the different time intervals, and an anomaly is detected based on the calculated differences.
The method for detecting an abnormality in a plasma processing apparatus according to any one of claims 1 to 7. a mounting table for mounting a substrate inside a processing chamber for processing the substrate;
a rectangular planar window member facing a mounting surface of the mounting table and dividing an interior of the processing chamber into an upper portion and a lower portion;
a plurality of antenna coils arranged along an imaginary rectangular plane corresponding to the window member;
A control unit that detects an abnormality,
Each of the plurality of antenna coils has one end connected to a high frequency power source and the other end connected to a ground potential via an ammeter;
the imaginary rectangular plane is at least partially partitioned into a plurality of areas in which any one of the plurality of antenna coils is disposed;
the virtual rectangular plane has a portion partitioned into a plurality of integrated areas each of which is a combination of the areas disposed at symmetrical positions on the virtual rectangular plane,
The control unit detects an abnormality based on a current value measured by the ammeter for the antenna coil disposed in each of the areas included in each of the plurality of integrated areas.
Plasma processing equipment. The virtual rectangular plane is divided into a plurality of concentric rectangular areas, and the plurality of integrated areas are defined at least in an outer area located at the outermost periphery of the plurality of concentric rectangular areas.
The plasma processing apparatus according to claim 10. The plurality of integrated areas are defined in all of the plurality of concentric rectangular areas.
The plasma processing apparatus according to claim 11 .

Images