Substrate processing apparatus and substrate processing method

Abstract

The present invention relates to a substrate processing apparatus and a substrate processing method. Deposition generated around a substrate due to processing of the substrate is prevented from adhering to the substrate. The apparatus is configured to include: a processing container; a plasma formation mechanism that forms a plasma in a processing space for processing the substrate; a stage that is provided in the processing space for placing the substrate, includes a portion composed of metal; a first high-frequency power source that supplies high frequency for bias to the stage; an upper ring that is an insulator, surrounds the stage in a manner so as not to overlap the stage in plan view, and is provided facing the processing space; a lower ring that is a ring-shaped insulator, is provided below the upper ring for supporting the upper ring, and surrounds a side periphery of the stage; and a metal member that is provided between the upper ring and the lower ring for introducing the plasma to the upper ring, is separated from the stage, and is formed along the upper ring.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to a substrate processing apparatus and a substrate processing method. BACKGROUND

[0002] A substrate is subjected to plasma processing such as etching. As for an apparatus that performs such plasma processing, there is a structure in which a ring member that surrounds a substrate is provided in order to cause plasma to be concentrated on the substrate, and a high frequency for bias application is supplied to an electrode that constitutes a stage on which the substrate is placed. Patent Documents 1 to 3 show an apparatus having such a structure.

[0003] PRIOR ART DOCUMENTS

[0004] PATENT DOCUMENTS

[0005] Patent Document 1: Japanese Patent Application Publication No. 2016-127090

[0006] Patent Document 2: Japanese Patent Application Publication No. H11-74099

[0007] Patent Document 3: Japanese Patent Application Publication No. 2014-36026 SUMMARY

[0008] PROBLEMS TO BE SOLVED BY THE INVENTION

[0009] An object of the present disclosure is to provide a technology capable of preventing deposition generated around a substrate due to processing performed on the substrate from adhering to the substrate.

[0010] SOLUTION TO PROBLEM

[0011] A substrate processing apparatus according to the present disclosure includes:

[0012] a processing container that has a processing space in which a substrate is accommodated;

[0013] a plasma formation mechanism that forms plasma in the processing space in order to process the substrate;

[0014] a stage that is provided in the processing space in order to place the substrate, the stage including a portion composed of a metal;

[0015] a first high-frequency power source that supplies a high frequency for bias to the stage;

[0016] an upper ring that is an insulator, surrounds the stage in a manner not to overlap the stage in plan view, and is disposed facing the processing space;

[0017] a lower ring that is an annular insulator, is provided below the upper ring in order to support the upper ring, and surrounds a side periphery of the stage; and

[0018] A metal component, disposed between the upper ring and the lower ring for introducing the plasma into the upper ring, is detached from the stage and formed along the circumference of the upper ring when viewed from above.

[0019] The effects of the invention

[0020] This disclosure can prevent deposits generated around the substrate due to the processing of the substrate from adhering to the substrate. Attached Figure Description

[0021] Figure 1 This is a longitudinal sectional side view of an etching apparatus according to one embodiment of the substrate processing apparatus disclosed herein.

[0022] Figure 2 This is a longitudinal sectional side view of the stage of the etching apparatus.

[0023] Figure 3 This is a longitudinal sectional side view of the stage.

[0024] Figure 4 This is a schematic bottom view of the focusing ring located on the stage.

[0025] Figure 5 This is a longitudinal sectional side view of the stage during the etching process. Detailed Implementation

[0026] Refer to the longitudinal sectional side view Figure 1 The etching apparatus 1 of one embodiment of the substrate processing apparatus of this disclosure will be described. This etching apparatus 1 supplies an etching gas as a processing gas to a processing container 12 (described later), and etches a film formed on the surface of the substrate G by plasmaizing the processing gas. The plasma is inductively coupled plasma. The substrate G is rectangular when viewed from above, and is, for example, a glass substrate used in the manufacture of FPDs (Flat Panel Displays). More specifically, the substrate G is, for example, a substrate used in the manufacture of liquid crystal displays (LCDs), electroluminescent displays (ELs), plasma display panels (PDPs), etc.

[0027] The etching apparatus 1 includes a cylindrical, metal, and grounded main body container 11. Inside the main body container 11, a metal window 2, which is a metal component, divides the interior of the main body container 11 into an upper antenna chamber 3 and a lower processing container 12. Therefore, the metal window 2 forms the top wall of the processing container 12. Furthermore, the processing container 12 is configured with a processing space 13 for accommodating and processing the substrate G.

[0028] A metal support frame 18 is provided between the side wall of the antenna chamber 3 and the side wall of the processing container 12, and the support frame 18 protrudes inward toward the main container 11. Furthermore, the aforementioned metal window 2 is supported by the support frame 18 via an insulating member 21, thereby insulating the metal window 2 relative to the processing container 12. In addition, the metal window 2 is divided laterally to form multiple partitions 22. As an example, this division is along a radial straight line extending circumferentially from or near the center of the metal window 2 toward the corners. For ease of illustration, [the following is omitted as it is not explicitly stated in the original text]. Figure 1 The division along the radial straight line is not shown. Insulating members 21 are also provided between the division portions 22 to insulate them from each other. Alternatively, in addition to circumferential division, areas at different distances from the center of the metal window 2 can also be divided.

[0029] The dividing section 22 includes a main body 23 and a spray plate 24 disposed on the lower side relative to the main body 23. The spray 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 spray plate 24. Furthermore, processing gas is supplied from the gas supply section 27 to the gas diffusion space 26 of each dividing section 22, and the processing gas is ejected from the gas outlets 25 into the processing space 13. Therefore, the metal window 2 constitutes a spray head.

[0030] An antenna 31 is provided in the antenna chamber 3, which is separated from and faces the metal window 2. The antenna 31 is formed to surround the circumference of the metal window 2. Specifically, the antenna 31 can be configured, for example, as a multi-layered coil structure wound around the center of the metal window 2 when viewed from above. Furthermore, a high-frequency power supply 33 is connected to the antenna 31 via a matching device 32.

[0031] If high-frequency power is supplied to the antenna 31 via the high-frequency power supply 33, an induced current is generated on the upper surface of each segment 22 constituting the metal window 2. This induced current becomes an eddy current that flows sequentially on the side, lower, side, and upper surfaces of each segment 22. Utilizing the current flowing on the lower surface of the segment 22 within this eddy current, an induced electric field is formed in the processing space 13, thereby plasmaifying the processing gas. The metal window 2 is configured as a segment 22 with mutually insulated and segmented structures, thereby suppressing the induced current generated on the upper surface of the metal window 2 from becoming an eddy current circulating only on that upper surface, and instead making the induced current become an eddy current passing through the lower surface of the metal window 2 (i.e., the lower surface of each segment 22). Alternatively, multiple coil-shaped antenna segments formed with their winding axes parallel to the upper surface of the metal window 2 can be arranged circumferentially on the metal window 2, and high frequency can be supplied to each antenna segment to generate eddy currents passing through the lower surface of the segment 22, thereby achieving plasmaification. The metal window 2, antenna 31, matching device 32, and high-frequency power supply 33, which serves as the second high-frequency power supply, constitute a plasma formation mechanism.

[0032] Next, the structure of the processing container 12 will be described. A transport port 15 for the substrate G, which is opened and closed by a gate valve 14, is formed on the side wall of the processing container 12. Furthermore, a stage 4 for placing the substrate G is provided at the center of the bottom surface of the processing container 12. Moreover, multiple exhaust ports 16 are provided around the stage 4 on the bottom surface. By using an exhaust mechanism 17 to exhaust air from the exhaust ports 16, thereby creating a vacuum atmosphere inside the processing container 12, the aforementioned plasma is generated, and the substrate G is processed.

[0033] The following also refers to the longitudinal sectional side view of the stage 4. Figure 2 , Figure 3 Please provide an explanation. Additionally... Figure 2 , Figure 3 The insulator ring 5 and focusing ring 6, described later, are shown with longitudinal cross-sections at different locations. Regarding the stage 4, its circumferential surfaces from the upper to the lower surface are formed as flat square pillars, and when viewed from above, its periphery is rectangular along the circumference of the substrate G on which it is placed. The stage 4 has a lower electrode 43, which is a metal block.

[0034] Furthermore, the upper side of the stage 4 is configured as an electrostatic chuck 44, which is stacked on the lower electrode 43. The electrostatic chuck 44 includes a chuck dielectric film 45 and a chuck electrode 46 embedded in the chuck dielectric film 45. In order to obtain the electrostatic attraction force of the electrostatic chuck 44 relative to the substrate G, a DC power supply 47 is connected to the chuck electrode 46. In addition, a high-frequency power supply 49 is connected to the lower electrode 43 via a matching device 48. The high-frequency power supply 49, as a first high-frequency power supply, is used to apply a bias voltage to the substrate G placed on the electrostatic chuck 44, and by supplying high frequency to the lower electrode 43, ions constituting plasma are introduced into the substrate G.

[0035] A flow path for a temperature-regulated fluid is formed within the lower electrode 43. Furthermore, a flow path for a heat transfer gas is formed via the lower electrode 43 toward the electrostatic chuck 44 and opening on the upper surface of the electrostatic chuck 44, thereby facilitating heat transfer between the substrate G and the stage 4. Moreover, for transferring the substrate G between the external transport mechanism of the etching apparatus 1 and the electrostatic chuck 44, a lifting pin is configured to penetrate the stage 4 vertically and protrude from the surface of the electrostatic chuck 44 and be embedded therein. The flow paths for the temperature-regulated fluid, the heat transfer gas, and the lifting pin are not shown in the figures.

[0036] Furthermore, a support member 40 made of an insulator is provided on the bottom surface of the processing container 12. The support member 40 is configured as a square ring. The support member 40 is provided along the periphery of the lower electrode 43, and the inner periphery of the support member 40 supports the periphery of the lower electrode 43. Moreover, an insulator ring 5 is provided on the support member 40. The insulator ring 5 is configured as a square ring that surrounds the side periphery of the stage 4 throughout its entire circumference, and has the function of suppressing abnormal discharge on the side periphery of the stage 4 when plasma is formed in the processing space 13. The insulator ring 5 is configured to extend from a height position lower than the upper surface of the lower electrode 43 to a height position of the lower surface of the lower electrode 43.

[0037] The insulator ring 5 is rectangular in longitudinal section and is composed of insulators forming the inner and outer peripheral edges of the ring. The inner peripheral side of the insulator ring 5 is in close contact with the outer peripheral side 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.

[0038] Regarding the corners of the sides of the lower electrode 43 mentioned above, recesses 53 are formed by removing local portions in the longitudinal direction (see reference). Figure 3A support member 54 made of an insulator is provided so as to engage with the recess 53. A portion of the support member 54 protrudes outward from the lower electrode 43 and is received in a notch 55 on the upper surface of a corner of the inner circumference of the insulator ring 5, and is supported by the insulator ring 5. Two upward-facing pins 56 are provided at the portion of the support member 54 that protrudes from the lower electrode 43. Figure 3 (Only one is shown in the image), the pin 56 is located near each of the two sides of the lower electrode 43, which is rectangular when viewed from above. Additionally, the insulator ring 5 and the support member 54 constitute the lower ring supporting the inner periphery of the focusing ring 6.

[0039] Furthermore, on the bottom surface of the processing container 12, a square-shaped annular spacer 57, which is an insulator, is provided to surround the insulator ring 5 and the support member 40 throughout the entire circumference. The inner circumferential side of the spacer 57 is in close contact with the outer circumferential side of the support member 40 and the insulator ring 5.

[0040] A focusing ring 6, serving as an insulator, is provided on the insulator ring 5 and the spacer 57. Additionally, Figure 4 The lower surface of the focusing ring 6 is shown. This focusing ring 6, serving as the upper ring, is a square ring-shaped component, designed to surround the outer side of the upper portion of the stage 4 throughout its entire circumference, with its upper surface facing the processing space 13. A lower surface is provided opposite to (parallel to) this upper surface, serving to focus plasma above the substrate G placed on the stage 4. The inner and outer peripheral edges of the focusing 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 focusing ring 6 does not overlap with the stage 4 when viewed from above. The upper surface of the focusing ring 6 is located slightly lower than the upper surface of the electrostatic chuck 44. On the other hand, using the upper surface of the electrostatic chuck 44 as the mounting area, the substrate G is mounted with its peripheral end located slightly outside the peripheral edge of the stage 4. Therefore, a small gap is created between the back surface of the peripheral portion of the substrate G and the upper surface of the inner peripheral portion of the focusing ring 6.

[0041] The focusing ring 6 is composed of four elongated rectangular plates 61. As described above, since the focusing ring 6 is a square ring, it is constructed in a circumferential manner to form a rectangle, with each of the four plates 61 forming a corner and an edge extending from that corner. Therefore, two of the four plates 61 are longer than the other two plates 61. Each plate 61 has a pair of opposing sides along the length direction and a pair of opposing end sides orthogonal to the length direction. In addition, it has an upper surface facing the processing space 13 and a lower surface opposite to the upper surface. To describe the positional relationship between the plates 61 in more detail, one plate 61 is opposite and adjacent to the sides of the other two plates 61 on different sides. More specifically, a side of one plate 61 in the length direction is adjacent to the side of one end of the first other plate 61. Moreover, the side of one end of one plate 61 is adjacent to the side in the length direction of a second other plate 61 that is different from the side of the first other plate in the length direction. Furthermore, when observing any two adjacent plates 61 of the four plates 61, one end of the other plate is located on the extension line of the length direction of one plate 61, and the other end of the other plate extends in a direction orthogonal to the length direction of one plate 61.

[0042] A recess 62 is formed on the lower surface of each of the four plates 61 at one end and the other end along their length. Figure 3 The pin 56 of the support member 54, as described above, is inserted into and fitted into the recess 62 to fix the lateral position of each plate 61, thereby forming a focusing ring 6. Furthermore, to accommodate the expansion and contraction of the plates 61 due to temperature changes, one of the two recesses 62 of a plate 61 is longer in the longitudinal direction of the plate 61 than the other recess 62. In addition to positioning the plates 61, the pin 56 also supports the focusing ring 6. Therefore, the inner peripheral side of the focusing ring 6 is supported by the insulator ring 5 using the pin 56. The outer peripheral side of the focusing ring 6 is supported by the spacer 57.

[0043] like Figure 3 As shown, the recess 62 of plate 61 can be detached from pin 56. That is, the focusing ring 6 is configured to be easily detached from and installed relative to the insulator ring 5 and spacer 57. Alternatively, in addition to utilizing the engagement between the recess 62 and pin 56, a fastener such as a threaded component can also be used to install plate 61 relative to the insulator ring 5 and spacer 57. When using a fastener for installation, plate 61 can be detached from the insulator ring 5 and spacer 57 by removing the fastener.

[0044] The metal film 63 and the insulating film 64 are formed, for example, by sputtering in the area overlapping the insulating ring 5 on the lower surface of the focusing ring 6 when viewed from above. The metal film 63 is made of, for example, W (tungsten), and the insulating film 64 is made of, for example, Y2O3 (yttrium oxide). The metal film 63 is formed along the circumference of the focusing ring 6. More specifically, the metal film 63 is formed as a strip on each of the four plates 61, extending along the length of the plate 61. Moreover, the metal film 63 of an adjacent plate 61 is separated from the metal film 63 of another plate 61, so that when the entire lower surface of the focusing ring 6 is observed, the metal film 63 is formed as a square ring with slits at each corner.

[0045] The edge of the metal film 63 on the inner peripheral side of the focusing ring 6 is separated from the inner peripheral side of the focusing ring 6. That is, the metal film 63 is formed separately from the lower electrode 43. The edge of the metal film 63 on the outer peripheral side of the focusing ring 6 is located at a position separated from the spacer 57 near the inner peripheral side of the focusing ring 6, and is located closer to the outer peripheral side of the focusing ring 6 than the periphery of the substrate G placed on the stage 4. That is, when viewed from above, at least a portion of the metal film 63 is located outside the substrate G placed on the stage 4. The metal film 63 has a potential due to the action of the high-frequency power supply 49, thereby acting on the plasma in the processing space 13, and has the function of preventing the deposition of reaction products generated by the processing of the substrate G on the upper surface of the focusing ring 6 in the area above the metal film 63, the function of which will be described in detail later.

[0046] The insulating film 64 serves to prevent abnormal discharge (sparking) caused by contact between the plasma entering the lower surface of the focusing ring 6 from the processing space 13 and the metal film 63. For its purpose, the insulating film 64 covers the entire metal film 63 in a manner that does not expose it, with the edges of the metal film 63 and the insulating film 64 separated. Therefore, the insulating film 64 is also formed along the circumference of the focusing ring 6, more specifically, in a square annular shape. Thus, the inner periphery of the annular insulating film 64 is aligned, for example, with the inner periphery of the focusing ring 6, and the outer periphery of the insulating film 64 is located at a position separated from the spacer 57 near the stage 4. Furthermore, the insulating film 64 and the metal film 63 are not formed in the recess 62 and its periphery to avoid interference with the pin 56. Figure 4 In the diagram, numerous dots are marked to indicate the insulating film 64 formed by three of the four plates 61, and a dashed line indicates the other plate 61. Figure 4 The end edge of the insulating film 64 (below). Moreover, in this other plate 61, diagonal lines are marked to indicate the metal film 63.

[0047] The reasons for providing the aforementioned metal film 63 and its function will be explained in detail. First, let's describe the device structure assuming the metal film 63 is not provided in the focusing ring 6. The lower electrode 43, which constitutes the stage 4 and is subjected to a high frequency for bias formation, has a flat and vertical outer peripheral surface. Because it has such an outer peripheral surface, it differs from the structure shown in Patent Documents 2 and 3, where the outer peripheral surface of the lower electrode 43 partially forms an outwardly protruding flange, and the focusing ring 6 and this flange overlap when viewed from above. Therefore, because the flange (partially the lower electrode 43) and the focusing ring 6 do not overlap, the formation of an electric field on the focusing ring 6 by supplying a high frequency to the lower electrode 43 is suppressed. Consequently, the effect of this electric field, i.e., the introduction of ions, one of the active species of plasma, toward the upper surface of the focusing ring 6, is suppressed. Therefore, the etching effect on the upper surface of the focusing ring 6 achieved by ion sputtering is suppressed.

[0048] On the other hand, reaction products are generated by the processing gas used to process the substrate G and the film formed on the surface of the substrate G, which is the object of processing. As described above, since the etching effect on the upper surface of the focusing ring 6 is relatively small, the reaction products are deposited along the upper surface of the focusing ring 6 to form an annular film 60 (shown later), and the inner edge of the annular film 60 may be relatively close to the substrate G. As a result, particles generated when the annular film 60 is peeled off may adhere to the substrate G, potentially reducing the yield.

[0049] The metal film 63 serves to prevent the deposition of reaction products like these near the substrate G, thereby increasing the distance between the aforementioned annular film 60 and the substrate G. Specifically, when plasma is formed in the processing space 13, a high-frequency current is supplied from the high-frequency power supply 49 to the lower electrode 43, thereby creating an electric field between the lower electrode 43 and the plasma. This attracts ions from the plasma towards the lower electrode 43, thus processing the substrate G.

[0050] The metal film 63 is separated from the lower electrode 43, 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 considered as a capacitance component. When a high frequency is supplied to the lower electrode 43, a portion of the high frequency is supplied from the lower electrode 43 to the metal film 63, generating a potential in the metal film 63. Thus, an electric field is also formed above the metal film 63, and this electric field is used to introduce ions from the plasma toward the lower electrode 43. Consequently, the etchability is relatively high in the region directly above and near the metal film 63 on the upper surface of the focusing ring 6, preventing the formation of a ring-shaped film 60 of deposits in these regions. In other words, it prevents the deposition of reaction products on the upper surface of the focusing ring 6 near the substrate G, as described above.

[0051] However, assuming the metal film 63 is closer to the stage 4 than in the example described above, and is configured to contact the lower electrode 43, the metal film 63 is close to the end of the insulating film 64. Therefore, the insulation of the contact area between the metal film 63 and the lower electrode 43 is insufficient for the plasma flowing near the contact area as it enters the lower surface of the focusing ring 6 from the processing space 13, which is considered prone to causing abnormal discharge. Consequently, the structure for shielding the plasma at the contact area may become complicated when preventing this discharge. In other words, by configuring the metal film 63 to be separate from the lower electrode 43, the discharge can be prevented using a simple device structure such as an insulating film 64 covering the entire metal film 63. Therefore, such a configuration is preferred.

[0052] Furthermore, if the metal film 63 is configured to contact the lower electrode 43, a portion of the power from the high-frequency power supply 49 used for processing the substrate G, supplied towards the lower electrode 43, is more dispersed and supplied to the metal film 63, which contributes less to the processing of the substrate G. This results in power loss relative to the lower electrode 43. While the metal film 63 is smaller in volume than the lower electrode 43, and therefore this power loss is minimal, from the viewpoint of suppressing such loss and processing the substrate G more quickly, it is preferable to configure the metal film 63 as described above, separating it from the lower electrode 43.

[0053] Furthermore, in this structure where the metal film 63 is provided, the position of the annular film 60 formed by the deposit is controlled by the range of the metal film 63. Suppose that in the device with the aforementioned structure where the lower electrode 43 has a flange, in order to adjust or test the device, it is desired to change the width of the flange to control the position of the annular film 60 formed by the deposit. Since the lower electrode 43 is a relatively large component, such a change in shape could be large-scale, and the size and position of the components surrounding the lower electrode 43 would also need to be appropriately changed. In other words, as a design change of the device, since it is large-scale, the cost and labor of the device could increase. However, according to this structure where the metal film 63 is provided, only the positions of the metal film 63 and the insulating film 64 need to be changed; therefore, the design change of the device is limited to a small scale, thus suppressing cost and labor.

[0054] Furthermore, since the focusing ring 6, which is equipped with the metal film 63 and the insulating film 64, can be easily attached and detached from the insulating ring 5 and the spacer 57 as described above, it is easy to control the position of the annular film 60 of the deposit. For example, by preparing multiple focusing rings 6 with different positions for forming the metal film 63, the position can be controlled by changing the focusing ring 6.

[0055] Furthermore, as described above, the metal film 63 is formed only locally in the width direction of the focusing ring 6. Moreover, the center position in the width direction of the focusing ring 6 (in...) Figure 2 Compared to P1), the center position of the metal film 63 in the width direction (in) Figure 2 The metal film 63 (represented as P2) is located near the stage 4. By forming the metal film 63 in this way, the location of the above-mentioned reaction product deposition is made much farther away from the substrate G on the stage 4, and the formation range of the metal film 63 and the insulating film 64 covering the metal film 63 is suppressed to be a wider range (e.g., the entire lower surface of the focusing ring 6), which has the advantage of being able to reduce the manufacturing cost of the device.

[0056] In addition, the etching apparatus 1 includes a control unit 10 (see reference 10). Figure 1 The control unit 10 includes a program. The program contains instructions (step groups) to execute the processing of the substrate G in the following sequence by sending control signals to various parts of the etching apparatus 1. Specifically, the control signals are sent to control various actions such as switching on and off the high-frequency power supplies 33 and 49 and the DC power supply 47, supplying processing gas from the gas supply unit 27, and adjusting the vacuum pressure within the processing space 13 by exhausting gas from the exhaust mechanism 17. The program is stored, for example, on a storage medium such as an optical disc, hard disk, or DVD, and loaded into the control unit 10.

[0057] Next, the operation of the etching apparatus 1 will be described. When the substrate G is transported into the processing container 12 using a transport mechanism (not shown), the substrate G is placed on a temperature-adjusted stage 4 using a lifting pin (not shown). The temperature of the substrate G is adjusted using a heat transfer gas, and the atmosphere inside the processing container 12 is vented to a vacuum atmosphere at the desired pressure. Then, processing gas is sprayed from the spray plate 24 into the processing space 13, and the high-frequency power supplies 33 and 49 are turned on. Eddy currents are formed in the metal window 2, causing the processing gas to plasmaize. At this time, the substrate G is adsorbed onto the stage 4 using an electrostatic chuck 44.

[0058] Figure 5This is a schematic diagram illustrating the state during plasma formation, with arrows indicating ions in the plasma. An electric field is formed on the lower electrode 43 by a high-frequency supply from the high-frequency power supply 49, and ions in the plasma of the processing space 13 are introduced downwards toward the lower electrode 43, etching the surface of the substrate G. The reaction products generated at this time adhere to the focusing ring 6. However, as described above, ions are introduced toward the region directly above the metal film 63 on the upper surface of the focusing ring 6, and this region and the nearby reaction products are etched. Therefore, reaction products cannot be deposited in such highly etchable regions, but only on the outer side of these regions. As a result, the inner edge of the annular film 60, which prevents the formation of deposits, is located near the substrate G.

[0059] Then, the ejection of processing gas from the spray plate 24 is stopped, and the high-frequency power supplies 33 and 49 are disconnected, thereby stopping the processing of the substrate G. The substrate G is then transported from the stage 4 to the outside of the processing container 12 by means of a lifting pin and a conveying mechanism. As described above, according to the etching apparatus 1, the position of the annular film 60 of the deposit generated by the processing of the substrate G can be moved away from the substrate G to a large extent, thus suppressing the adhesion of the deposit to the substrate G.

[0060] Furthermore, regarding the focusing ring 6, in order to reliably prevent abnormal discharge by covering the entire metal film 63 formed for each plate 61 with the insulating film 64, as described above, when viewing the focusing ring 6 as a whole, the metal film 63 is formed in a ring shape with gaps. Compared to the case where no metal film 63 is provided, as long as the formation position of the aforementioned annular film 60 of the deposit can be separated from the substrate G in the circumferential direction relative to the substrate G, the ring formed by the metal film 63 can be discontinuous. Among them, if the metal film 63 forms a seamless ring, the circumferential direction of the substrate G and the annular film 60 of the deposit can be separated more reliably, so a seamless structure is also possible. That is, the case of forming the metal film 63 along the circumference of the focusing ring 6 (upper ring) includes either the case where the metal film 63 is formed in a ring shape with gaps or the case where the metal film 63 is formed in a ring shape without gaps.

[0061] Furthermore, the metal film 63 and the insulating film 64 are formed by sputtering, but the formation method is arbitrary. For the materials constituting the films, electroplating, vapor deposition, coating, etc., can also be used to form the films. Moreover, regarding the metal constituting the metal film 63, any metal can be used as long as it achieves the aforementioned effects; therefore, it is not limited to tungsten. Regarding the insulating film 64, any insulator can be used as long as it can prevent abnormal discharge caused by the metal film 63; therefore, it is not limited to Y₂O₃.

[0062] Furthermore, in the above example, a metal film 63 is provided as a metal component to control the position of the annular film 60 formed by the deposit. However, the metal component is not limited to a metal film 63; for example, it could also be a metal plate. When a metal plate is provided instead of a metal film 63, for example, a recess is provided on the lower surface of the focusing ring 6 and the metal plate is disposed within the recess. Then, an insulating adhesive material or filler material is filled into the recess, and the gap between the sidewall of the recess and the metal plate is filled using the adhesive material or filler material. The lower surface side of the metal film is also covered using the adhesive material or filler material.

[0063] Furthermore, the recessed portion where the metal plate is arranged and filled with adhesive or filler material can be provided on the upper surface of the insulator ring 5 instead of the focusing ring 6. Therefore, while the metal member is provided between the focusing ring 6 and the insulator ring 5, it is also possible for the metal member to be fixedly provided relative to either the focusing ring 6 or the insulator ring 5.

[0064] Furthermore, an example of applying this technology to an etching apparatus is shown, but its application is not limited to such apparatus; for example, it can also be applied to a film deposition apparatus. Furthermore, regarding the shape of the substrate to be processed, it is not limited to the rectangular substrate as described above; it can also be circular. In this case, as long as the stage 4 is set to be circular in plan view corresponding to the shape of the substrate, and each component of the focusing ring 6, the insulator ring 5, the metal film 63, and the insulator film 64 is set to be annular in plan view, it is sufficient. Additionally, even when it is set to annular, the metal film 63 can have either gaps or no gaps.

[0065] Furthermore, this technology is not limited to devices that generate plasma by arranging a metal window 2 and an antenna 31 above a stage 4 as described above. For example, a spray head, which constitutes an upper electrode paired with the lower electrode 43, can be arranged above the stage 4 in a manner opposite to the stage 4. Thus, a structure can be configured to supply high frequencies for plasma generation from a high-frequency power supply 33 to the spray head. That is, this technology can also be applied to parallel-plate type plasma generation devices.

[0066] Furthermore, the embodiments disclosed herein should be considered illustrative rather than restrictive in all respects. The above-described embodiments may also be omitted, substituted, modified, or combined in various ways without departing from the appended claims and their spirit.

[0067] [Evaluation Test]

[0068] Evaluation tests related to this technology will be described. In these tests, a test apparatus having a structure substantially the same as that of the etching apparatus 1 described above was used to etch the substrate G, and the adhesion of the deposits after this process to the focusing ring 6 was investigated. As a difference between this test apparatus and the etching apparatus 1, the case in which two adjacent plates 61 of the four plates 61 constituting the focusing ring 6 are not provided with a metal film 63 and an insulating film 64 is listed. Furthermore, regarding the other two adjacent plates 61, similar to the etching apparatus 1, a metal film 63 and an insulating film 64 are formed, but the thickness of the insulating film 64 differs between the plates 61.

[0069] As described above, the insulating film 64 serves to prevent abnormal discharge by covering the metal film 63. From the viewpoint of manufacturing cost suppression, it is preferable that the thickness of the insulating film 64 is small. However, if the thickness of the insulating film 64 is too small, dielectric breakdown may occur in the insulating film 64, causing the aforementioned discharge. In this evaluation test, in addition to confirming the effectiveness of the metal film 63, the purpose is also to verify the appropriate thickness of the insulating film 64.

[0070] Specifically, in the experimental setup, the insulating film 64 of one plate 61 has a thickness of 100 μm, and the insulating film 64 of the other plate 61 has a thickness of 150 μm. Furthermore, the metal film 63 covered by these insulating films 64 has a thickness of 50 μm. The metal film 63 and the insulating film 64 are the same as those listed in the embodiment, and are composed of W and Y₂O₃, respectively. Furthermore, the metal film 63 is formed to have a width of 26.5 cm. The end of the metal film 63 on the inner peripheral side of the focusing ring 6 is separated by 2 mm from the inner peripheral edge of the focusing ring 6. The insulating film 64 is formed to have a width of 30.5 mm. Moreover, as described in the embodiment, the end of the insulating film 64 on the inner peripheral side is aligned with the inner peripheral edge of the focusing ring 6.

[0071] The processing conditions for the evaluation test are described. A mixture of CF4 and O2 gases was used as the processing gas. The pressure in the processing space 13 during the processing was 10 mTorr (1.33 Pa), and the power supplied to the high-frequency power supplies 33 and 49 was 20 kW each. Furthermore, although omitted from description in this embodiment, the metal window 2 and the sidewalls of the processing container 12 are equipped with temperature adjustment mechanisms such as heaters and cooling channels, allowing for temperature adjustment. The temperature of the metal window 2 and the processing container 12 was 80°C. The temperature of the stage 4 was 15°C. The etching process on the substrate G lasted for two hours. Additionally, a polyimide component was used as the substrate G to facilitate confirmation of deposit adhesion. That is, the deposit was generated by etching the polyimide.

[0072] When the upper surface of the focusing ring 6 is observed after etching, an annular film 60 formed by the deposit is formed. This annular film 60 has a portion extending linearly along the inner periphery of the focusing ring 6. The distance between the linear portion of the annular film 60 and the inner periphery of the focusing ring 6 varies between the plates 61. On the two plates 61 where the metal film 63 is not formed, the distance is 18 mm, and on the two plates 61 where the metal film 63 is formed, the distance is 28 mm. Therefore, according to this evaluation test, it is confirmed that by providing the metal film 63, the effect described in the embodiment, such as increasing the distance between the periphery of the substrate G and the annular film 60 of the deposit, can be obtained.

[0073] Furthermore, upon observing the lower surfaces of the two plates 61, which are provided with the metal film 63 and the insulating film 64 after etching, no traces of abnormal discharge were found. Therefore, it was confirmed that a film thickness of 100 μm and 150 μm for the insulating film 64 is acceptable. Thus, based on this evaluation test, it was confirmed that a film thickness of 100 μm or more for the insulating film 64 is acceptable, and it was shown that a minimum film thickness of 100 μm within this range is preferred.

Claims

1. A substrate processing apparatus, wherein, The substrate processing apparatus includes: A processing container having a processing space inside to accommodate a substrate; A plasma forming mechanism that forms plasma in the processing space for processing the substrate; A stage, provided in the processing space for placing the substrate, has a flat and vertical outer peripheral surface and includes a portion made of metal. The first high-frequency power supply supplies high-frequency bias voltage to the stage. The upper ring, which is an insulator, surrounds the platform in a manner that does not overlap with the platform when viewed from above, and is set facing the ground with the processing space. A lower ring, which is a ring-shaped insulator, is disposed below the upper ring to support it, surrounding the side periphery of the stage; and A metal component, disposed between the upper ring and the lower ring for attracting the plasma toward the upper ring, is separated from the stage and formed along the circumference of the upper ring.

2. The substrate processing apparatus according to claim 1, wherein, The metal component is located on the upper ring.

3. The substrate processing apparatus according to claim 2, wherein, The metal component is a metal membrane, and an insulating membrane is provided to cover the metal membrane.

4. The substrate processing apparatus according to claim 3, wherein, The center of the metal film in the width direction is located closer to the stage than the center of the upper ring in the width direction.

5. The substrate processing apparatus according to any one of claims 1 to 4, wherein, The plasma forming mechanism includes: an antenna disposed above the stage; and a second high-frequency power supply that supplies high frequency to the antenna.

6. The substrate processing apparatus according to any one of claims 1 to 4, wherein, The upper ring can be easily assembled and disassembled relative to the lower ring.

7. A substrate processing method, wherein, The substrate processing method includes the following steps: The substrate is housed in a processing container that has internal processing space. The substrate is processed by forming plasma in the processing space using a plasma forming mechanism. The substrate is placed on a stage provided in the processing space, which has a flat and vertical outer peripheral surface and includes a portion made of metal. Using the first high-frequency power supply, a high-frequency bias voltage is supplied to the stage; and The plasma is attracted to the upper ring by a metal member located between the upper and lower rings, separated from the stage and formed along the circumference of the upper ring. The upper ring is an insulator that surrounds the stage in a manner that does not overlap with the stage when viewed from above, and is disposed facing the ground with respect to the processing space. The lower ring is a ring-shaped insulator that is located below the upper ring to support it and surrounds the side periphery of the stage.

8. The substrate processing method according to claim 7, wherein, The process of forming the plasma to process the substrate includes the following steps: A high-frequency signal is supplied from a second high-frequency power source constituting the plasma forming mechanism to an antenna located above the stage constituting the plasma forming mechanism.

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