JP7700637B2 - SUBSTRATE PROCESSING APPARATUS AND SUBSTRATE PROCESSING METHOD - Google Patents

Description

This disclosure relates to a substrate processing apparatus and a substrate processing method.

Plasma processing such as etching is performed on a substrate. In some cases, the apparatus for performing this plasma processing is configured so that a ring member is provided that surrounds the substrate in order to focus the plasma on the substrate, and high frequency waves for applying a bias are supplied to an electrode that constitutes a stage on which the substrate is placed. Patent documents 1 to 3 show apparatus with such a configuration.

JP 2016-127090 A Japanese Patent Application Publication No. 11-74099 JP 2014-36026 A

The present disclosure aims to provide a technology that can prevent deposits that occur around a substrate as a result of processing the substrate from adhering to the substrate.

The substrate processing apparatus according to the present disclosure includes a processing vessel having a processing space for storing a substrate therein;
a plasma generating mechanism for generating plasma in the processing space to process the substrate;
a stage provided in the processing space for placing the substrate thereon, the stage including a portion made of metal;
a first high frequency power supply that supplies a high frequency for bias to the stage;
an upper ring that is an insulator and that surrounds the stage so as not to overlap the stage in a plan view and faces the processing space;
a lower ring, which is a ring-shaped insulator provided below the upper ring to support the upper ring and surrounds a side periphery of the stage;
a metal member provided between the upper ring and the lower ring for drawing the plasma into the upper ring, the metal member being spaced from the stage and formed along a circumference of the upper ring in a plan view;
Equipped with.

The present disclosure can prevent deposits that occur around a substrate as a result of processing the substrate from adhering to the substrate.

1 is a vertical sectional side view of an etching apparatus according to an embodiment of a substrate processing apparatus of the present disclosure. FIG. 2 is a vertical sectional side view of a stage provided in the etching apparatus. FIG. FIG. 4 is a schematic bottom view of a focus ring provided on the stage. 3 is a vertical sectional side view showing a stage during processing by the etching apparatus. FIG.

An etching apparatus 1, which is an embodiment of a substrate processing apparatus according to the present disclosure, will be described with reference to FIG. 1, which is a longitudinal side view. This etching apparatus 1 supplies an etching gas as a processing gas to a processing vessel 12 described below, and etch a film formed on the surface of the substrate G by converting the processing gas into plasma. This plasma is inductively coupled plasma. The substrate G is rectangular in plan view, and is, for example, a glass substrate for manufacturing FPDs (Flat Panel Displays). More specifically, the substrate G is a substrate for manufacturing, for example, liquid crystal displays (LCDs), electroluminescence (EL) displays, plasma display panels (PDPs), etc.

The etching apparatus 1 includes a main vessel 11 that is rectangular, made of metal, and grounded. Inside the main vessel 11, a metal window 2, which is a metal member, is provided, and the inside of the main vessel 11 is divided by the metal window 2 into an antenna chamber 3 on the upper side and a processing vessel 12 on the lower side. The metal window 2 therefore forms the ceiling wall of the processing vessel 12. The inside of the processing vessel 12 is configured as a processing space 13 for storing and processing substrates G.

A metal support shelf 18 is provided between the side wall of the antenna chamber 3 and the side wall of the processing vessel 12, and the support shelf 18 protrudes inside the main vessel 11. The metal window 2 is supported by the support shelf 18 via an insulating member 21, so that the metal window 2 is insulated from the processing vessel 12. The metal window 2 is divided laterally to form a plurality of divided sections 22. As an example, this division is made in the circumferential direction along radial straight lines from the center or near the center of the metal window 2 to the corners. However, for convenience of illustration, FIG. 1 does not show the division along the radial straight lines. An insulating member 21 is also provided between the divided sections 22, so that the divided sections 22 are insulated from each other. In addition to dividing the metal window 2 in the circumferential direction, regions at different distances from the center of the metal window 2 may be divided.

The division 22 includes a main body 23 and a shower plate 24 disposed below the main body 23. The shower plate 24 has a plurality of gas outlets 25, each of which communicates with a gas diffusion space 26 formed between the main body 23 and the shower plate 24. A process gas is supplied from a gas supply unit 27 to the gas diffusion space 26 of each division 22, and the process gas is discharged from the gas outlets 25 into the process space 13. Thus, the metal window 2 forms a shower head.

An antenna 31 is provided in the antenna chamber 3, and is spaced apart from the metal window 2 and faces the metal window. The antenna 31 is formed so as to go around the circumferential direction of the metal window 2. Specifically, the antenna 31 can be configured, for example, as a coil wound multiple times around the center of the metal window 2 in a plan view. A high-frequency power source 33 is connected to the antenna 31 via a matching device 32.

When high-frequency power is supplied to the antenna 31 by the high-frequency power source 33, an induced current is generated on the upper surface of each divided portion 22 constituting the metal window 2, and this induced current becomes an eddy current that flows repeatedly through the side, lower, side, and upper surface of each divided portion 22 in sequence. The current that flows through the lower surface of the divided portion 22 among these eddy currents forms an induced electric field in the processing space 13, and converts the processing gas into plasma. Since the metal window 2 is configured to be insulated from each other as the divided portions 22 and divided, the induced current generated on the upper surface of the metal window 2 is prevented from becoming an eddy current that only loops around the upper surface, and becomes an eddy current that passes through the lower surface of the metal window 2 (i.e., the lower surface of each divided portion 22) described above. In addition, a plurality of coil-shaped antenna segments each formed so that the winding axis is parallel to the upper surface of the metal window 2 may be arranged in the circumferential direction of the metal window 2, and high frequency may be supplied to each antenna segment to form an eddy current that passes through the lower surface of the divided portion 22 described above, thereby converting the processing gas into plasma. The metal window 2, the antenna 31, the matching box 32, and the second high-frequency power supply 33 constitute the plasma generation mechanism.

Next, the configuration of the processing vessel 12 will be described. A transfer port 15 for the substrate G, which is opened and closed by a gate valve 14, is formed in the side wall of the processing vessel 12. A stage 4 for placing the substrate G is provided in the center of the bottom surface of the processing vessel 12. A plurality of exhaust ports 16 are opened around the stage 4 on the bottom surface. The above-mentioned plasma is generated and the substrate G is processed by exhausting air from the exhaust ports 16 using an exhaust mechanism 17, creating a vacuum atmosphere inside the processing vessel 12.

The following description will also refer to Figures 2 and 3, which are longitudinal side views of stage 4. Note that Figures 2 and 3 show longitudinal side views at different positions of the insulator ring 5 and focus ring 6 described below. The side surfaces of stage 4 from the top to bottom are configured as flat rectangular columns, and in plan view the periphery forms a rectangle that follows the circumference of the substrate G to be placed on it. Stage 4 is equipped with a lower electrode 43, which is a metal block body.

The upper side of the stage 4 is configured as an electrostatic chuck 44, which is laminated on the lower electrode 43. The electrostatic chuck 44 is composed of a chuck dielectric film 45 and a chuck electrode 46 embedded in the chuck dielectric film 45. A DC power supply 47 is connected to the chuck electrode 46 so that the electrostatic chuck 44 can electrostatically attract the substrate G. A high-frequency power supply 49 is connected to the lower electrode 43 via a matching unit 48. The high-frequency power supply 49, which is a first high-frequency power supply, is used to apply a bias to the substrate G placed on the electrostatic chuck 44, and the supply of high-frequency power to the lower electrode 43 causes ions that constitute the plasma to be attracted to the substrate G.

A flow path for a temperature-adjusted fluid is formed within the lower electrode 43. A flow path for a heat transfer gas is also formed through the lower electrode 43 toward the electrostatic chuck 44 and opens to the upper surface of the electrostatic chuck 44, and heat is transferred between the substrate G and the stage 4 via the heat transfer gas. Lift pins are provided to pass the substrate G between the transport mechanism outside the etching apparatus 1 and the electrostatic chuck 44, penetrating the stage 4 vertically and protruding from the surface of the electrostatic chuck 44. The flow paths for the temperature-adjusting fluid, the flow paths for the heat transfer gas, and the lift pins are not shown in the figure.

A support member 40 made of an insulator is provided on the bottom surface of the processing vessel 12. The support member 40 is configured in a square ring shape. The support member 40 is provided along the periphery of the lower electrode 43, and the inner periphery side of the support member 40 supports the periphery of the lower electrode 43. An insulator ring 5 is provided on the support member 40. The insulator ring 5 is configured as a square ring that surrounds the entire side circumference of the stage 4, and has the role of suppressing abnormal discharge on the side circumference of the stage 4 when plasma is generated in the processing space 13. The insulator ring 5 is provided so as to extend from a height position lower than the upper surface of the lower electrode 43 to the height position of the lower surface of the lower electrode 43.

The insulator ring 5 is rectangular in vertical cross section and is made of insulators that form the inner and outer peripheral edges of the ring. The inner peripheral side surface of the insulator ring 5 is in close contact with the outer peripheral side surface of the stage 4, and the bottom surface of the insulator ring 5 is in close contact with the upper surface of the support member 40.

At each corner of the side of the lower electrode 43, a portion in the vertical direction is cut out to form a recess 53 (see FIG. 3), and a support member 54 made of an insulator is provided to engage with the recess 53. A portion of the support member 54 protrudes outside the lower electrode 43 and fits into a notch 55 on the upper surface of the inner corner of the insulator ring 5, and is supported by the insulator ring 5. Two pins 56 pointing upward are provided at the portion of the support member 54 protruding from the lower electrode 43 (only one is shown in FIG. 3), and the pins 56 are located near each of the two sides of the lower electrode 43, which is rectangular in plan view. The insulator ring 5 and the support member 54 form a lower ring that supports the inner edge side of the focus ring 6.

A rectangular ring-shaped insulator spacer 57 is provided on the bottom surface of the processing vessel 12 so as to completely surround the insulator ring 5 and the support member 40. The inner peripheral side of the spacer 57 is in close contact with the outer peripheral side of the support member 40 and the insulator ring 5.

An insulator focus ring 6 is provided on the insulator ring 5 and the spacer 57. FIG. 4 shows the bottom surface of the focus ring 6. The focus ring 6, which is the upper ring, is a rectangular ring-shaped member that surrounds the entire outer periphery of the upper part of the stage 4, and is provided so that its upper surface faces the processing space 13, and its lower surface is provided opposite (parallel to) the upper surface, and has the role of converging plasma above the substrate G placed on the stage 4. The inner and outer peripheral edges of the focus ring 6 are located on the inner peripheral end of the insulator ring 5 and the outer peripheral end of the spacer 57, respectively. Therefore, the focus ring 6 does not overlap with the stage 4 in a plan view. The upper surface of the focus ring 6 is located slightly below the upper surface of the electrostatic chuck 44. On the other hand, the substrate G is placed on the upper surface of the electrostatic chuck 44 as a placement area, with its peripheral edge located slightly outside the periphery of the stage 4 described above. Therefore, a small gap is created between the back surface of the peripheral edge of the substrate G and the top surface of the inner peripheral edge of the focus ring 6.

The focus ring 6 is composed of four long rectangular plates 61. As described above, the focus ring 6 is a square ring and is configured to form a perimeter of a rectangle, and the four plates 61 each form one corner of the rectangle and one side extending from the corner. Therefore, two of the four plates 61 are longer than the other two plates 61. Each plate 61 has a pair of opposing side surfaces along the length direction and a pair of end side surfaces that are perpendicular to the length direction and opposed to each other. It also has an upper surface facing the processing space 13 and a lower surface opposed to the upper surface. To describe the positional relationship between the plates 61 in more detail, one plate 61 faces and is adjacent to the side surfaces of the other two plates 61 at different sides. More specifically, one side surface in the length direction of one plate 61 is adjacent to one end side surface of the first other plate 61. The side of one end of one plate 61 is adjacent to the side in the longitudinal direction of a second other plate 61 that is different from the first other plate that is in contact with the side in the longitudinal direction. When any two of the four adjacent plates 61 are viewed, one end of the other plate is located on the extension line of the length of the first plate 61, and the other end of the other plate extends in a direction perpendicular to the length of the first plate 61.

The four plates 61 each have a recess 62 formed on the underside at one end and the other end in the length direction. The pins 56 of the support member 54 described in FIG. 3 are inserted into the recesses 62 to fix the lateral position of each plate 61, thereby forming the focus ring 6. In order to accommodate expansion and contraction of the plate 61 due to temperature changes, one of the two recesses 62 in one plate 61 is longer in the length direction of the plate 61 than the other recess 62. The pins 56 not only serve to position the plate 61, but also support the focus ring 6. Therefore, the inner peripheral side of the focus ring 6 is supported by the insulator ring 5 via the pins 56. The outer peripheral side of the focus ring 6 is supported by the spacer 57.

As shown in FIG. 3, the recess 62 of the plate 61 can be removed from the pin 56. That is, the focus ring 6 is configured to be freely attached and detached from the insulator ring 5 and the spacer 57. In addition to utilizing the engagement between the recess 62 and the pin 56, the plate 61 may be attached to the insulator ring 5 and the spacer 57 by using a fastener such as a screw. Even when the plate 61 is attached using a fastener in this way, the plate 61 can be removed from the insulator ring 5 and the spacer 57 by removing the fastener.

A metal film 63 and an insulator film 64 are formed by, for example, thermal spraying in a region of the lower surface of the focus ring 6 that overlaps with the insulator ring 5 in a plan view. The metal film 63 is made of, for example, W (tungsten), and the insulator film 64 is made of, for example, Y ₂ O ₃ (yttrium oxide). The metal film 63 is formed along the circumference of the focus ring 6. More specifically, the metal film 63 is formed in a band shape on each of the four plates 61 so as to extend along the length direction of the plate 61. The metal film 63 of one plate 61 and the metal film 63 of the other plate 61 adjacent to each other are separated from each other, so that when the entire lower surface of the focus ring 6 is viewed, the metal film 63 is formed in a square ring shape with cuts at each corner.

The edge of the metal film 63 on the inner peripheral side of the focus ring 6 and the inner peripheral edge of the focus ring 6 are separated from each other. That is, the metal film 63 is formed away from the lower electrode 43. The edge of the metal film 63 on the outer peripheral side of the focus ring 6 is located away from the spacer 57 toward the inner peripheral edge of the focus ring 6, and is located closer to the outer peripheral edge of the focus ring 6 than the peripheral edge of the substrate G placed on the stage 4. That is, in a plan view, at least a part of the metal film 63 is located outside the substrate G placed on the stage 4. The action of the metal film 63 will be described in detail later, but the metal film 63 has a potential due to the action of the high frequency power supply 49, and acts on the plasma in the processing space 13, and plays a role in preventing reaction products generated by processing the substrate G from accumulating in the area above the metal film 63 on the upper surface of the focus ring 6.

The insulating film 64 has a role of preventing abnormal discharge (arcing) from occurring due to contact between the plasma that has entered the lower surface of the focus ring 6 from the processing space 13 and the metal film 63. For this purpose, the insulating film 64 covers the entire metal film 63 so that the metal film 63 is not exposed, and the edge of the metal film 63 is separated from the edge of the insulating film 64. Therefore, the insulating film 64 is also formed along the circumference of the focus ring 6, and more specifically, is formed in a square ring shape. The inner edge of the insulating film 64, which is annular in this way, is aligned with the position of the inner edge of the focus ring 6, for example, and the outer edge of the insulating film 64 is located away from the spacer 57 toward the stage 4. Note that the insulating film 64 and the metal film 63 are not formed in the recess 62 and its surroundings to avoid interference with the pin 56. In FIG. 4, the insulating film 64 formed on three of the four plates 61 is shown with multiple dots, and the edge of the insulating film 64 on the remaining plate 61 (lower in FIG. 4) is shown with a dashed line. And on that remaining plate 61, the metal film 63 is shown with diagonal lines.

The reason for providing the metal film 63 and its action will be described in detail. First, an explanation will be given assuming that the focus ring 6 does not have the metal film 63. The lower electrode 43, which constitutes the stage 4 and to which the high frequency for forming the bias is applied, has a flat and vertical outer circumferential surface. Since it has such an outer circumferential surface, it is different from the configuration shown in Patent Documents 2 and 3 in which a part of the outer circumferential surface of the lower electrode 43 forms a flange that protrudes outward and the focus ring 6 and the flange overlap in a plan view. And, since the flange (part of the lower electrode 43) and the focus ring 6 do not overlap in this way, the formation of an electric field on the focus ring 6 due to the supply of high frequency to the lower electrode 43 is suppressed. Therefore, the attraction of ions, which are one of the active species of plasma, toward the upper surface of the focus ring 6, which is the action of this electric field, is suppressed. Therefore, the etching action on the upper surface of the focus ring 6 due to the sputtering of ions is suppressed.

Meanwhile, reaction products are generated from the process gas used to process the substrate G and the film formed on the surface of the substrate G to be processed. As described above, because the etching effect on the upper surface of the focus ring 6 is relatively small, the reaction products are deposited along the upper surface of the focus ring 6 to form an annular film 60 (described later), and there is a risk that the inner edge of the annular film 60 and the substrate G will be relatively close to each other. If this happens, the annular film 60 may peel off, producing particles that may adhere to the substrate G, thereby reducing the yield.

The metal film 63 prevents the deposition of reaction products near the substrate G and serves to relatively increase the distance between the annular film 60 and the substrate G. Specifically, when plasma is formed in the processing space 13, a high frequency is supplied from the high frequency power supply 49 to the lower electrode 43, forming an electric field between the lower electrode 43 and the plasma, and ions in the plasma are drawn toward the lower electrode 43 to process the substrate G.

The metal film 63 and the lower electrode 43 are spaced apart, but the metal film 63 is located near the lower electrode 43. Therefore, the space between the metal film 63 and the lower electrode 43 is regarded as a capacitance component, and when a high frequency is supplied to the lower electrode 43, a part of the high frequency is supplied from the lower electrode 43 to the metal film 63, and a potential is generated in the metal film 63. An electric field is also formed above the metal film 63, and the ions in the plasma are attracted toward the lower electrode 43 by the electric field. Therefore, the etching property of the area directly above the metal film 63 and the area nearby the area on the upper surface of the focus ring 6 is relatively high, and the formation of the annular film 60 of deposits in those areas is prevented. In other words, as described above, the deposition of reaction products on the upper surface of the focus ring 6 near the substrate G is prevented.

Now, let us suppose that the metal film 63 is closer to the stage 4 side than in the above-mentioned example, and is in contact with the lower electrode 43. In that case, the metal film 63 is closer to the end of the insulator film 64, and therefore the contact portion between the metal film 63 and the lower electrode 43 is considered to have insufficient insulation against plasma that enters the underside of the focus ring 6 from the processing space 13 and flows near the contact portion, making it easier for abnormal discharge to occur. Therefore, in order to prevent the discharge, the structure for shielding the plasma at the contact portion may become complicated. From another perspective, by arranging the metal film 63 away from the lower electrode 43, the discharge can be prevented with a simple device configuration in which an insulator film 64 is provided to cover the entire metal film 63, so such an arrangement is preferable.

In addition, if the metal film 63 is configured to be in contact with the lower electrode 43, a portion of the power of the high frequency power source 49 supplied to the lower electrode 43 used to process the substrate G will be distributed and supplied more to the metal film 63, which has a smaller contribution to the processing of the substrate G. This results in a power loss to the lower electrode 43. Since the volume of the metal film 63 is smaller than the lower electrode 43, the amount of this power loss is small, but from the viewpoint of suppressing such loss and processing the substrate G more quickly, it is preferable to position the metal film 63 away from the lower electrode 43, as described above.

In addition, in this configuration in which the metal film 63 is provided, the position where the annular film 60 of the deposit is formed is controlled by the range where the metal film 63 is provided. Suppose that in the above-mentioned device in which a flange is provided on the lower electrode 43, the width of the flange is changed to control the position where the annular film 60 of the deposit is formed for adjustment or testing of the device. Since the lower electrode 43 is a relatively large member, such a change in shape may be large-scale, and the size and position of each member around the lower electrode 43 will also need to be changed appropriately. In other words, the design change of the device will be large-scale, and there is a risk that the cost and effort of the device will increase. However, with this configuration in which the metal film 63 is provided, the design change of the device will be small because it is only necessary to change the positions of the metal film 63 and the insulator film 64, so the cost and effort can be reduced.

Furthermore, since the focus ring 6 on which the metal film 63 and the insulator film 64 are provided can be attached and detached from the insulator ring 5 and the spacer 57 as described above, the position of the annular film 60 of the deposits can be easily controlled. For example, by preparing multiple focus rings 6 with different positions on which the metal film 63 is formed, and using the focus rings 6 interchangeably, the position can be controlled.

As described above, the metal film 63 is formed only partially in the width direction of the focus ring 6. The center position of the metal film 63 in the width direction (shown as P2 in FIG. 2) is located closer to the stage 4 than the center position of the focus ring 6 in the width direction (shown as P1 in FIG. 2). By forming the metal film 63 in this manner, the position where the reaction products are deposited can be relatively far away from the substrate G on the stage 4, while preventing the formation range of the metal film 63 and the insulator film 64 covering the metal film 63 from becoming wide (for example, the entire lower surface of the focus ring 6), which has the advantage of reducing the manufacturing costs of the device.

The etching apparatus 1 also includes a control unit 10 (see FIG. 1), which includes a program. The program contains commands (steps) to execute processing of the substrate G in the procedure described below by sending control signals to each part of the etching apparatus 1. Specifically, each operation, such as turning on and off the high frequency power supplies 33, 49 and the DC power supply 47, supplying processing gas from the gas supply unit 27, and adjusting the vacuum pressure in the processing space 13 by exhausting with the exhaust mechanism 17, is controlled by sending the above control signals. The above program is stored in a storage medium, such as a compact disc, hard disk, or DVD, and installed in the control unit 10.

Next, the operation of the etching apparatus 1 will be described. When the substrate G is transported into the processing vessel 12 by a transport mechanism (not shown), the substrate G is placed on the temperature-adjusted stage 4 via lift pins (not shown). The temperature of the substrate G is adjusted via a heat transfer gas, and the processing vessel 12 is evacuated to a vacuum atmosphere of the desired pressure. Then, processing gas is discharged from the shower plate 24 into the processing space 13, and the high-frequency power supplies 33 and 49 are turned on. The above-mentioned eddy current is formed in the metal window 2, and the processing gas is turned into plasma. At this time, the substrate G is attracted to the stage 4 by the electrostatic chuck 44.

Figure 5 is a schematic diagram showing the state during plasma formation, with arrows indicating ions in the plasma. An electric field is formed on the lower electrode 43 by the supply of high frequency from the high frequency power supply 49, and ions in the plasma in the processing space 13 are drawn downward toward the lower electrode 43, etching the surface of the substrate G. Assume that the reaction products generated at that time are attached to the focus ring 6. However, as described above, the ions are drawn toward the region directly above the metal film 63 on the upper surface of the focus ring 6, and the reaction products in and near that region are etched. Therefore, the reaction products cannot be deposited in such a region with a relatively high etching property, and are deposited only outside that region. As a result, the inner edge of the annular film 60 formed by the deposits is prevented from being located near the substrate G.

Then, the discharge of the processing gas from the shower plate 24 stops, and the high frequency power supplies 33, 49 are turned off to stop the processing of the substrate G, and the substrate G is transported from the stage 4 to the outside of the processing vessel 12 via the lift pins and the transport mechanism. As described above, according to the etching apparatus 1, the position of the annular film 60 of deposits generated by the processing of the substrate G can be relatively far away from the substrate G, so that the adhesion of the deposits to the substrate G is suppressed.

As for the focus ring 6, in order to reliably prevent abnormal discharge by covering the entire metal film 63 formed on each plate 61 with the insulator film 64, as described above, the metal film 63 is formed to have a ring shape with a gap when viewed as the entire focus ring 6. As long as the formation position of the above-mentioned annular film 60 of deposits can be separated from the substrate G with respect to the entire circumference of the substrate G, as compared with the case where the metal film 63 is not provided, the ring formed by the metal film 63 may be interrupted in this way. However, if the metal film 63 forms a ring without a gap, the entire circumference of the substrate G can be more reliably separated from the annular film 60 of deposits, so such a configuration without a gap may be acceptable. In other words, the formation of the metal film 63 along the circumference of the focus ring 6 (upper ring) includes both the formation of the metal film 63 in a ring shape with a gap and the formation of the metal film 63 in a ring shape without a gap.

Although the metal film 63 and the insulator film 64 are formed by thermal spraying, any method of formation may be used, and the material constituting the film may be formed by plating, vapor deposition, coating, etc. The metal constituting the metal film 63 is not limited to tungsten as long as it has the effects already described, and any metal may be used. The insulator film 64 is also not limited to _Y2O3 as long as _it can prevent the occurrence of abnormal discharge due to the provision of the metal film 63, and any insulator may be used.

In the above example, the metal film 63 is provided as a metal member to control the position where the annular film 60 of the deposit is formed, but the metal member is not limited to the metal film 63 and may be, for example, a metal plate. When providing a metal plate instead of the metal film 63, for example, a recess is provided on the lower surface of the focus ring 6 and the metal plate is placed in the recess. Then, the recess is filled with an insulating adhesive or filler, and the gap between the side wall of the recess and the metal plate is filled with the adhesive or filler, and the lower surface side of the metal film is covered with the adhesive or filler.

The recess in which the metal plate is provided and in which the adhesive or filler is filled may be provided on the upper surface of the insulator ring 5 instead of on the focus ring 6. Therefore, the metal member is provided between the focus ring 6 and the insulator ring 5, but the metal member may be fixed to either the focus ring 6 or the insulator ring 5.

In addition, while an example of applying this technology to an etching device has been shown, the application is not limited to such devices, and the technology may be applied to, for example, a film forming device. The shape of the substrate to be processed is not limited to the rectangular substrate in plan view described above, but may be circular. In that case, the stage 4 may be circular in plan view to match the shape of the substrate, and the focus ring 6, insulator ring 5, metal film 63, and insulator film 64 may each be annular in plan view. Even in such a case where the metal film 63 is annular, the metal film 63 may or may not have a break.

Furthermore, the present technology is not limited to application to an apparatus that forms plasma by forming an eddy current by arranging the metal window 2 and antenna 31 above the stage 4 as described above. For example, a shower head that forms an upper electrode paired with the lower electrode 43 can be arranged above the stage 4 so as to face the stage 4. Then, a high frequency power for plasma formation can be supplied to the shower head from the high frequency power supply 33. In other words, the present technology may be applied to a parallel plate type plasma forming apparatus.

The embodiments disclosed herein should be considered to be illustrative and not restrictive in all respects. The above embodiments may be omitted, substituted, modified, or combined in various ways without departing from the scope and spirit of the appended claims.

[Evaluation test]
An evaluation test related to the present technology will be described. In this evaluation test, a test device having a configuration similar to that of the etching device 1 described above was used to perform an etching process on a substrate G, and the state of deposition on the focus ring 6 after the process was examined. The difference between this test device and the etching device 1 is that, of the four plates 61 constituting the focus ring 6, two adjacent plates 61 are not provided with a metal film 63 and an insulator film 64. In addition, the other two adjacent plates 61 are formed with a metal film 63 and an insulator film 64 as in the etching device 1, but the thickness of the insulator film 64 differs between the plates 61.

As described above, the insulator film 64 has the role of preventing abnormal discharge by covering the metal film 63. From the viewpoint of reducing the manufacturing costs of the device, it is preferable that the thickness of the insulator film 64 is small, but if the thickness of the insulator film 64 is too small, there is a risk that dielectric breakdown will occur in the insulator film 64 and the above-mentioned discharge will occur. In addition to confirming the action and effect of the metal film 63, the purpose of this evaluation test is to verify the appropriate thickness of the insulator film 64.

Specifically, in the test device, the thickness of the insulating film 64 on one plate 61 was 100 μm, and the thickness of the insulating film 64 on the other plate 61 was 150 μm. The thickness of the metal film 63 covering these insulating films 64 was 50 μm. The metal film 63 and the insulating film 64 were made of W and Y ₂ O ₃ , respectively, as in the example given in the embodiment. The metal film 63 was formed to have a width of 26.5 cm. The end of the metal film 63 on the inner periphery side of the focus ring 6 was 2 mm away from the inner periphery of the focus ring 6. The insulating film 64 was formed to have a width of 30.5 mm. As described in the embodiment, the end of the insulating film 64 on the inner periphery side was formed to be aligned with the inner periphery of the focus ring 6.

The processing conditions of the evaluation test will be described. A mixed gas of _CF4 gas and _O2 gas was used as the processing gas, the pressure in the processing space 13 during processing was 10 mTorr (1.33 Pa), and the power supplied to the high frequency power sources 33 and 49 was 20 kW each. Although not described in the embodiment, the metal window 2 and the side wall of the processing vessel 12 are provided with a temperature control mechanism such as a heater and a cooling channel so as to adjust the temperature. The temperature of the metal window 2 and the processing vessel 12 was set to 80°C. The temperature of the stage 4 was set to 15°C. The etching processing time for the substrate G was set to 2 hours. The substrate G was made of polyimide in order to easily check the adhesion of the deposit. That is, the deposit was generated by etching the polyimide.

When the top surface of the focus ring 6 was observed after etching, an annular film 60 made of deposits was formed, and the annular film 60 had a portion that extended linearly along the inner peripheral edge of the focus ring 6. The distance between the linear portion of the annular film 60 and the inner peripheral edge of the focus ring 6 differed between the plates 61. On the two plates 61 on which the metal film 63 was not formed, the distance was 18 mm, and on the two plates 61 on which the metal film 63 was formed, the distance was 28 mm. Therefore, it was confirmed from this evaluation test that the effect described in the embodiment, that is, the distance between the peripheral edge of the substrate G and the annular film 60 of deposits was increased, could be obtained by providing the metal film 63.

Then, when the undersides of the two plates 61 provided with the metal film 63 and the insulator film 64 after etching were observed, no evidence of abnormal discharge was found, and it was confirmed that there was no problem with either the thickness of the insulator film 64 being 100 μm or 150 μm. Therefore, this evaluation test confirmed that the thickness of the insulator film 64 should be, for example, 100 μm or more, and showed that it is preferable to set the thickness to 100 μm, which is the smallest thickness within that range.

G Substrate 1 Etching device 12 Processing container 13 Processing space 2 Metal window 33 High frequency power source 4 Stage 5 Insulator ring 63 Metal film

Claims (8)

a processing vessel having a processing space for storing a substrate therein;
a plasma generating mechanism for generating plasma in the processing space to process the substrate;
a stage provided in the processing space for placing the substrate thereon, the stage including a portion made of metal;
a first high frequency power supply that supplies a high frequency for bias to the stage;
an upper ring that is an insulator and that surrounds the stage so as not to overlap the stage in a plan view and faces the processing space;
a lower ring, which is a ring-shaped insulator provided below the upper ring to support the upper ring and surrounds a side periphery of the stage;
a metal member provided between the upper ring and the lower ring for drawing the plasma into the upper ring, the metal member being spaced from the stage and formed along a circumference of the upper ring;
A substrate processing apparatus comprising: The substrate processing apparatus of claim 1, wherein the metal member is provided on the upper ring. The substrate processing apparatus according to claim 2, wherein the metal member is a metal film and an insulating film is provided to cover the metal film. 4. The substrate processing apparatus according to claim 3, wherein a center position in a width direction of the metal film is located closer to the stage than a center position in a width direction of the upper ring. A substrate processing apparatus according to any one of claims 1 to 4, wherein the plasma generating mechanism comprises an antenna provided above the stage and a second high-frequency power source that supplies high-frequency power to the antenna. A substrate processing apparatus according to any one of claims 1 to 5, wherein the upper ring is detachable from the lower ring. storing the substrate in a processing vessel having a processing space therein;
forming a plasma in the processing space by a plasma generating mechanism to process the substrate;
placing the substrate on a stage provided in the processing space and including a portion made of metal;
supplying a high frequency bias power to the stage by a first high frequency power source;
a step of drawing the plasma into the upper ring by a metal member disposed between an upper ring, which is an insulator surrounding the stage in a plan view so as not to overlap the stage and which faces the processing space, and a lower ring, which is a ring-shaped insulator disposed below the upper ring to support the upper ring and which surrounds a side periphery of the stage, and which is spaced apart from the stage and formed along a periphery of the upper ring;
A substrate processing method comprising: The step of forming a plasma to process the substrate includes:
8. The substrate processing method according to claim 7, further comprising the step of supplying a high frequency wave from a second high frequency power source constituting the plasma generating mechanism to an antenna provided above the stage constituting the plasma generating mechanism.

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