SUBSTRATE PROCESSING APPARATUS AND SUBSTRATE PROCESSING METHOD

Abstract

To locally and easily adjust the processing state at the peripheral edge of a substrate.SOLUTION: A substrate processing apparatus includes a processing container that stores a substrate, a stage provided in the processing container and having a mounting area on which the substrate is mounted, a gas supply unit that supplies processing gas for processing the substrate placed on the mounting area, an exhaust port for exhausting the inside of the processing container, a lower wall formed along the peripheral edge of the mounting area and provided on the stage so as to surround the substrate and having the same height of the upper end of the periphery, and an upper wall that locally protrudes upward around the lower wall and is formed separately from the lower wall.SELECTED DRAWING: Figure 1

Description

[Technical field]

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

[0002] Gas processing such as etching is performed on a substrate that is rectangular in plan view. In the gas processing apparatus, a square frame-shaped member (flow straightening wall) is provided surrounding the substrate to block the gas flow from the center to the outer periphery of the substrate, thereby adjusting the processing speed on the peripheral edge side of the substrate.

[0003] Patent Document 1 shows the member with the upper end formed at a uniform height. Patent Document 2 shows that the height of the four corners of the member is made lower than the height of other parts so that the retention of etching gas at the four corners of the substrate is suppressed. Patent Document 3 shows that the member is composed of multiple parts that are different in height and arranged horizontally. It is said that the degree of retention of etching gas in each part of the substrate can be adjusted by appropriately replacing each part. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2009-54720 A [Patent Document 2] JP 2003-243364 A [Patent Document 3] JP 2013-243184 A Summary of the Invention [Problem to be solved by the invention]

[0005] An object of the present disclosure is to provide a technique that can locally and easily adjust the processing state at the peripheral edge of a substrate. [Means for solving the problem]

[0006] The substrate processing apparatus according to the present disclosure includes a processing vessel for storing a substrate; a stage provided in the processing chamber and having a placement area on which the substrate is placed; a gas supply unit that supplies a processing gas for processing a substrate placed in the placement area; an exhaust port for exhausting the inside of the processing vessel; a lower wall provided on the stage so as to surround the substrate and be formed along a periphery of the mounting area; an upper wall that protrudes upward locally around the periphery of the lower wall and is formed separately from the lower wall; Equipped with. Effect of the Invention

[0007] The present disclosure allows for easy localized adjustment of processing conditions at the peripheral edge of a substrate. [Brief description of the drawings]

[0008] [Figure 1] 1 is a vertical sectional side view of an etching apparatus which is a substrate processing apparatus according to an embodiment of the present disclosure. [Diagram 2] 2 is a schematic perspective view of a stage and a straightening wall provided in the etching apparatus. FIG. [Diagram 3] FIG. [Figure 4] FIG. [Diagram 5] FIG. 4 is a perspective view of an upper wall and a lower wall that configure the flow straightening wall. [Figure 6] FIG. [Figure 7] FIG. 4 is a vertical sectional side view of the flow straightening wall. [Figure 8] FIG. [Figure 9] FIG. [Figure 10] FIG. 11 is an explanatory diagram showing the results of an evaluation test. [Figure 11]FIG. 11 is an explanatory diagram showing the results of an evaluation test. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] 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 vertical cross-sectional side view. The etching apparatus 1 supplies an etching gas as a processing gas to a substrate G, and etch an aluminum (Al) film or the like formed on the surface of the substrate G by converting the gas into plasma. The substrate G is, for example, a glass substrate for manufacturing FPDs (Flat Panel Displays), and more specifically, a substrate for manufacturing liquid crystal displays (LCDs), electroluminescence (EL) displays, plasma display panels (PDPs), and the like. The substrate G is rectangular, i.e., rectangular, in plan view.

[0010] The etching apparatus 1 includes a metal processing container 11 for storing and processing a substrate G therein, and the processing container 11 is grounded. A transfer port 13 for the substrate G that is opened and closed by a gate valve 12 is formed in a sidewall of the processing container 11.

[0011] A stage 21 is provided at the bottom of the processing vessel 11, and a substrate G is placed on the upper surface of the stage 21. The stage 21 is formed in a prismatic shape and includes a lower electrode 22 made of a conductive material such as a metal, and an annular member 23 made of an insulating material, and the annular member 23 covers the periphery of the lower electrode 22. The upper surface of the lower electrode 22 serves as a mounting surface 29 on which the substrate G is placed. The mounting surface 29 may be larger than the substrate G, or may be slightly smaller than the substrate G so that the periphery of the substrate G slightly protrudes beyond the periphery of the mounting surface 29. In either case, the mounting surface 29 is formed in a rectangular shape to fit the substrate G. The lower electrode 22 is connected to a high-frequency power source 25 via a matching device 24. An insulating member 26 is provided between the stage 21 and the bottom wall of the processing vessel 11 to insulate them from each other.

[0012] The stage 21 is provided with a number of lift pins 27 extending in the vertical direction. The lower end of each lift pin 27 is connected to a lift mechanism 28 provided outside the processing vessel 11 through an opening at the bottom of the processing vessel 11. The lift mechanism 28 may be provided in common for the multiple lift pins 27 as shown in FIG. 1, or may be provided individually. The lift pins 27 are raised and lowered in the vertical direction by the lift mechanism 28, and the substrate G is transferred between the upper surface of the stage 21 and a substrate transfer mechanism (not shown) that enters the processing vessel 11 through the transfer port 13. The stage 21 is provided with an electrostatic chuck for electrostatically adsorbing the substrate G placed thereon, a fluid flow path for adjusting the temperature of the upper surface of the stage 21, a heat transfer gas outlet for heat exchange between the upper surface of the stage 21 and the substrate G, and the like, but these are not shown in the figure.

[0013] A plurality of exhaust ports 14 are provided at the bottom of the processing vessel 11 at a position outside the stage 21. By providing the exhaust ports 14 at the bottom of the processing vessel 11 in this manner, each exhaust port 14 opens at a position lower than the upper surface of the stage 21 on which the substrate G is placed. One end of an exhaust pipe 15 is connected to the exhaust ports 14, and the other end of the exhaust pipe 15 is connected to an exhaust mechanism 17 constituted by a vacuum pump or the like. Air is exhausted from the exhaust ports 14 by the exhaust mechanism 17, and the inside of the processing vessel 11 is made into a vacuum atmosphere of a desired pressure.

[0014] The ceiling in the processing vessel 11 is configured as a shower head 31 facing the stage 21, and the shower head 31 is connected to a supply source 32 of an etching gas, which is a processing gas. An etching gas is supplied from the gas supply source 32 to the shower head 31, and the etching gas is discharged onto the stage 21 from a number of gas discharge ports 33 provided on the lower surface of the shower head 31. The shower head 31, which is a gas supply unit, is configured as a grounded upper electrode. The shower head 31 and the lower electrode 22 of the stage 21 form parallel plate electrodes for generating plasma.

[0015] As described in the Background Art section, when a substrate that is rectangular in plan view (hereinafter referred to as a rectangular substrate) such as the substrate G is processed in a substrate processing apparatus, a member (rectifying wall) surrounding the rectangular substrate may be provided to regulate and rectify the flow of gas around the rectangular substrate. On the other hand, the area in the surface of the rectangular substrate where uniform processing is desired is further expanded toward the peripheral edge of the rectangular substrate from the viewpoint of efficient use of the effective area in which a display can be manufactured from the rectangular substrate. In other words, it is required to improve the uniformity of processing over the entire surface of the substrate by aligning the processing state (etching amount in the case of etching) of the area near the peripheral edge of the rectangular substrate with the processing state of the central side of the rectangular substrate.

[0016] However, as will be described in detail later, if the heights of the upper ends are uniform around the periphery of the straightening wall (a frame-shaped part constituting the straightening wall, the same applies below. The same applies to the lower wall described below), the effect of the straightening wall is insufficient, and the processing speed in a local area near the peripheral edge of the rectangular substrate (peripheral end) becomes high. This causes excessive processing compared to other areas. As a result, there is a risk that the uniformity of the processing cannot be sufficiently increased within the surface of the substrate. The etching device 1 in this embodiment is configured to suppress excessive processing in the local area and solve the problem of uniformity of the processing described above by providing the straightening wall 4 described later. Here, "high uniformity" means that the uniformity is good, and means that the numerical value when the uniformity is quantified as a percentage based on the variation is "small". The same applies below, and when evaluating the uniformity numerically, the notations "large" and "small" are used.

[0017] In addition, the local region where the peripheral edge of the substrate is excessively processed, which occurs when the heights of the upper ends of the circumferential edges of the straightening walls are uniform, may vary depending on various processing conditions such as the pressure in the processing vessel and the supply amount of etching gas, and the position of an exhaust port in the processing vessel, which will be described later. To briefly describe the configuration here, the straightening walls 4 are configured by stacking an upper wall 42 on a lower wall 41 surrounding the substrate G or the mounting area on which the substrate G is mounted. The lower wall 41 and the upper wall 42 are separate members. Therefore, the upper wall 42 can be provided at a desired position in the circumferential direction of the lower wall 41, and the upper wall 42 can be provided in accordance with the position of the local region where the peripheral edge of the substrate G is excessively processed, which makes it easy to take measures to improve the uniformity of the processing.

[0018] The configuration of the stage 21 and its surroundings will be described below with reference to the perspective view of FIG. 2 and the plan view of FIG. 3. The upper surface of the stage 21 is a horizontal surface, and at least a part of it forms a mounting area on which the substrate G is mounted. The mounting area is an area that corresponds one-to-one to the substrate G with the same shape and area as the substrate G when the substrate G is mounted. The mounting area is included in the mounting surface 29 when the mounting surface 29 is larger than the substrate G, and includes the mounting surface 29 and relates to a part of the inner area of ​​the upper surface of the annular member 23 when the mounting surface 29 is smaller than the substrate G. The substrate G is mounted so that its center is aligned with the center of the upper surface of the stage 21. The upper surface of the stage 21 is rectangular in correspondence with the shape of the substrate G, and the above-mentioned straightening wall 4 is provided along the periphery of the upper surface so as to surround the substrate G on the stage 21.

[0019] The lower wall 41 constituting the straightening wall 4 is in the shape of a rectangular frame. The lower wall 41 is slightly separated from the periphery of the substrate G or the mounting area placed on the stage 21, and is provided along the periphery of the substrate G (i.e., along the periphery of the mounting area of ​​the substrate G). Therefore, the outer shape of the lower wall 41 in a plan view is rectangular. In the lower wall 41, the portions forming the two long sides of the rectangle are long wall portions 41A, and the portions forming the two short sides are short wall portions 41B. These long wall portions 41A and short wall portions 41B are each configured as a vertical plate, and the two long wall portions 41A, which are the first wall portions, face each other, and the two short wall portions 41B, which are the second wall portions, face each other. In addition, the first wall portion and the second wall portion are adjacent to each other. In the following description, the horizontal direction may be described as the X direction and the Y direction. These X direction and Y direction are each linear directions and are perpendicular to each other. In plan view, the long wall portion 41A and the long sides of the substrate G are aligned along the X direction, and the short wall portion 41B and the short sides of the substrate G are aligned along the Y direction.

[0020] The heights of the parts along the circumference of the lower wall 41 are the same. That is, the heights of the parts along the X direction of the long wall 41A are the same (the upper end is flat), and the heights of the parts along the Y direction of the short wall 41B are the same (the upper end is flat). The two opposing long wall parts 41A and the two opposing short wall parts 41B are the same height, and the adjacent long wall parts 41A and short wall parts 41B are also the same height. Therefore, the heights of the upper ends along the circumference of the lower wall 41 are uniform. Note that the uniform heights here mean that the heights are the same in design, and even if there is a slight deviation due to a slight inclination of the stage 21 or a manufacturing error of the lower wall 41, this is included in the uniform heights. Note that the upper end of the lower wall 41 is located above the surface of the substrate G.

[0021] The etching gas, which is supplied to the substrate G from the shower head 31 and turned into plasma, is exhausted from the exhaust port 14 located on the outside of the stage 21, and flows from the center to the periphery of the substrate G. The lower wall 41 blocks the etching gas flowing toward the periphery in this manner, forming a gas pool at the peripheral edge of the substrate G and reducing the flow rate. This suppresses the amount of unreacted plasma active species in the etching gas supplied to the peripheral edge of the substrate G, and as a result, the amount of etching at the peripheral edge is suppressed.

[0022] If the lower wall 41 were not provided, as explained in Patent Document 1, the supply of plasma active species to the peripheral portion would be excessive, and the etching rate (amount etched per unit time) would be likely to be higher at the peripheral portion of the substrate G than at the center of the substrate G. In other words, the lower wall 41 suppresses the etching rate at the peripheral portion of the substrate G, and increases the uniformity of the amount etched between the center and peripheral portion of the substrate G. In this example, the height of the lower wall 41 is 45 mm.

[0023] The upper wall 42 constituting the straightening wall 4 is provided to prevent the occurrence of a region where the amount of etching is locally increased at the peripheral edge of the substrate G. In order to describe the function of the upper wall 42 in detail, an evaluation test to be described in detail later will be briefly described. When processing was performed in the etching apparatus 1 with only the lower wall 41 provided without the upper wall 42, such a region where the amount of etching was locally increased (i.e., a region where the processing speed was high) occurred at the peripheral edge of the substrate G. Specifically, the amount of etching was relatively high in the region near each exhaust port 14. This is considered to be due to the fact that the etching gas is concentrated in the region near the exhaust port 14 by exhaust, so that the amount of the unreacted active species supplied is larger than in other regions, resulting in a high etching rate.

[0024] The upper wall 42 is provided around the periphery of the lower wall 41 so as to locally protrude upward from the upper end of the lower wall 41. Therefore, by providing the upper wall 42, the upper end of the flow straightening wall 4 is locally elevated around the periphery of the flow straightening wall 4. The upper wall 42 is provided near each exhaust port 14 on the lower wall 41. This enhances the effect of regulating the flow of the etching gas and causing it to remain at the peripheral end of the flow straightening wall 4, and reduces the amount of active species supplied to the region where the amount of etching would be high if the upper wall 42 was not provided.

[0025] In addition, in the vicinity of the exhaust port 14, particularly when a turbo molecular pump or the like is used as the vacuum pump of the exhaust mechanism 17, it is considered that particles once discharged through the exhaust port 14 together with the etching gas or the like will bounce back from the vacuum pump and flow backward from the exhaust port 14 side to reach the substrate G side from the exhaust port 14 side. The upper wall 42 also has the effect of restricting the rebound of particles toward the substrate G side and suppressing the particles from reaching the substrate G side, thereby suppressing contamination by particles in the region near the exhaust port 14. Such an action of the upper wall 42 suppresses contamination of the substrate G by rebound particles, while suppressing the etching amount from becoming high in a local region at the peripheral edge of the substrate G described above, and increases the uniformity of the etching amount in each part within the surface of the substrate G. It has been confirmed in an evaluation test that the provision of the upper wall 42 increases the uniformity of the etching amount in this way.

[0026] The configuration and arrangement of the upper wall 42 and the exhaust ports 14 in this embodiment will be described in detail below. The configuration and arrangement are the same as those in the evaluation test. In this embodiment, a total of eight exhaust ports 14 are provided, two along each long side of the mounting area on the stage 21 and two along each short side of the mounting area. The eight exhaust ports 14 are spaced apart from each other and open upward at the bottom of the processing vessel 11 so as to surround the stage 21 in a plan view. As shown in FIG. 3, the eight exhaust ports 14 are arranged symmetrically with respect to a virtual line L1 along the Y direction passing through the center of the long side of the mounting area on the stage 21 extending in the X direction, and symmetrically with respect to a virtual line L2 along the X direction passing through the center of the short side of the mounting area on the stage 21 extending in the Y direction, in a plan view. In addition, each exhaust port 14 is not provided at a corner of the stage 21 in a plan view, but opens at a position slightly closer to the center of the long side extending in the X direction of the stage 21 and slightly closer to the center of the short side extending in the Y direction than the corner.

[0027] The upper walls 42 are provided in eight, the same number as the number of exhaust ports 14, and are positioned apart from each other along the circumferential direction of the lower wall 41. Two of the eight upper walls 42 are arranged on each of the long wall portions 41A, and two are arranged on each of the short wall portions 41B. The upper walls 42 are plate-shaped, rectangular when viewed facing their main surfaces, and are provided so that their bottom surfaces are in contact with the upper end surface of the lower wall 41. Therefore, the heights of the upper ends of the upper walls 42 provided on the long wall portions 41A are uniform when viewed in the X direction, and the heights of the upper ends of the upper walls 42 provided on the short wall portions 41B are uniform when viewed in the Y direction. The heights of the upper walls 42 provided on the adjacent long wall portions 41A and short wall portions 41B are also uniform. That is, when viewed along the periphery of the lower wall 41, the heights of the upper ends of each portion of one upper wall 42 are uniform with respect to each other. And, the heights of the upper ends of different upper walls 42 are uniform. In this example, the height of the upper wall 42 is 30 mm. Due to this configuration, the width (length in the X direction) of the upper wall 42 provided on the long wall portion 41A is shorter than the width (length in the X direction) of the long wall portion 41A, and the width (length in the Y direction) of the upper wall 42 provided on the short wall portion 41B is shorter than the width (length in the Y direction) of the long wall portion 41A.

[0028] The arrangement of the upper wall 42 will be described in more detail. The upper wall 42 on the long wall portion 41A is positioned at a position shifted in the Y direction with respect to the exhaust port 14 positioned along the long side (along the X direction) of the mounting area. Moreover, the upper wall 42 on the short wall portion 41B is positioned at a position shifted in the X direction with respect to the exhaust port 14 positioned along the short side (along the Y direction) of the mounting area in a plan view. The reason for such an arrangement is that the upper wall 42 is positioned so as to separate, in a plan view, the region (later shown as regions G1 and G2) where the amount of etching is locally increased at the peripheral end of the substrate G when the upper wall 42 is not provided in the evaluation test, from the exhaust port 14, thereby achieving the effect of the upper wall 42 described above.

[0029] That is, when the substrate G is placed on the placement area, the region where the amount of etching is locally increased is located at the end along the long side of the substrate G, at a position sandwiching the upper wall 42 on the long wall portion 41A in the Y direction together with each of the exhaust ports 14 arranged in the X direction in a plan view. The region where the amount of etching is locally increased is located at the end along the short side of the substrate G, at a position sandwiching the upper wall 42 on the short wall portion 41B in the X direction together with each of the exhaust ports 14 arranged in the Y direction in a plan view. Note that, by being arranged in accordance with the exhaust ports 14 as described above, the eight upper walls 42 are separated from the four corners of the lower wall 41, and are arranged symmetrically with respect to the virtual line L1 and symmetrically with respect to the virtual line L2, similar to the exhaust ports 14.

[0030] In this embodiment, the width L4 of the upper wall 42 is larger than the diameter L3 of the exhaust port 14. The width L4 of the upper wall 42 is the length in the X direction for the upper wall 42 provided on the long wall portion 41A, and the length in the Y direction for the upper wall 42 provided on the short wall portion 41B. Due to the relationship between the diameter L3 and the width L4, when the exhaust port 14 arranged along the X direction and the upper wall 42 corresponding to the exhaust port 14 are viewed, the ends P3 and P4 in the X direction of the upper wall 42 are located outside in the X direction with respect to the ends P1 and P2 in the X direction of the exhaust port 14. When the exhaust port 14 arranged along the Y direction and the upper wall 42 corresponding to the exhaust port 14 are viewed, the ends P13 and P14 in the Y direction of the upper wall 42 are located outside in the Y direction with respect to the ends P11 and P12 in the Y direction of the exhaust port 14.

[0031] Therefore, when viewed from the substrate G in the X direction and the Y direction, the upper wall 42 is positioned so that each exhaust port 14 is entirely shielded by the upper wall 42. This more reliably suppresses the increase in the amount of active species supplied to the peripheral edge of the substrate G caused by the increase in the flow rate of the etching gas, as described above. In this example, the width L4 is 850 mm.

[0032] The lower wall 41 is connected to the lifting mechanism 40 (see FIG. 1). When a transport mechanism (not shown) transfers the substrate G onto the stage 21, the flow straightening wall 4 rises and moves away from the stage 21, so that the transfer can be performed without interfering with the movement of the transport mechanism. Alternatively, instead of lifting and lowering the lower wall 41, a rotation mechanism may be provided on the short wall portion 41B or the long wall portion 41A facing the transport port 13 to rotate them in a vertical plane, and the substrate G may be removed from the position for processing when the substrate G is transported.

[0033] The etching apparatus 1 also includes a control unit 10, which includes a program. The program incorporates commands (steps) for executing processing of the substrate G in a procedure described below by transmitting control signals to each part of the etching apparatus 1. Specifically, each operation, such as turning on and off the high frequency power supply 25, supplying an etching gas from the gas supply source 32, raising and lowering the lift pins 27 by the lifting mechanism 28, and raising and lowering the flow straightening wall 4 by the lifting mechanism 40, is controlled by transmitting the above control signals. The above program is stored in a storage medium, such as a compact disc, a hard disk, or a DVD, and installed in the control unit 10.

[0034] Next, the operation of the etching apparatus 1 will be described. When the substrate G is transported into the processing vessel 11 by a transport mechanism (not shown), the substrate G is placed on a temperature-adjusted mounting area on the stage 21 via the lift pins 27. The temperature of the substrate G is adjusted via a heat transfer gas supplied between the stage 21 and the substrate G, and the etching gas discharged from the shower head 31 is exhausted so that the processing vessel 11 becomes a vacuum atmosphere of a desired pressure. Then, the high-frequency power supply 25 is turned on, and the etching gas is turned into plasma and supplied to the substrate G, and the Al film formed on the surface of the substrate G is etched by the activated species of the plasma. The etching gas that did not contribute to the etching process of the substrate G and the reaction products generated by the etching flow from above the stage 21 to the outside of the stage 21 by exhaust from each exhaust port 14 and are exhausted from the processing vessel 11.

[0035] As described above, the flow of etching gas toward the outside of the stage 21 is suppressed by the flow straightening wall 4 at the peripheral edge of the substrate G, thereby suppressing the supply of activated species of plasma. As described above, the provision of the upper wall 42 allows such an effect to be fully exerted in the region near the exhaust port 14 at the peripheral edge of the substrate G, and prevents the etching rate from becoming locally high in that region. Therefore, etching proceeds with high uniformity in each part of the surface of the substrate G. Thereafter, the supply of etching gas from the shower head 31 is stopped, and the high frequency power supply 25 is turned off. Then, the substrate G is transferred to the transport mechanism via the lift pins 27 and is carried out of the processing vessel 11.

[0036] Incidentally, the upper wall 42 may be fixed to the lower wall 41 so as not to be detachable, for example, by using an adhesive or the like. However, as described above, it is considered that the position where the amount of etching is large may shift depending on the processing conditions. For this reason, it is preferable that the upper wall 42 is configured to be detachably fixed to the lower wall 41, and the position of the upper wall 42 on the lower wall 41 can be changed. FIG. 4 shows an example of such a detachable fixing of the upper wall 42 by using an adhesive sheet 51. In this example, an adhesive sheet 51 forming a second connecting portion is attached so as to straddle the lower wall 41 and the upper wall 42 on the outer side and / or inner side of the flow straightening wall 4, and the adhesive sheet 51 is fixed to each of the lower wall 41 and the upper wall 42 by the adhesive force of an adhesive surface 52 formed on the adhesive sheet 51. The adhesive surface 52 can be peeled off from the lower wall 41 and the upper wall 42, and the position of the upper wall 42 described above can be changed.

[0037] The adhesive sheet 51 may have adhesive surfaces 52 formed on both of the two main surfaces of the base material constituting the sheet, in which case the upper surface of the lower wall 41 and the lower surface of the upper wall 42 may be fixed by contacting them with the adhesive surfaces 52. The thicknesses of the lower wall 41 and the upper wall 42 are appropriately adjusted so that they can be fixed with sufficient strength, and the areas of the upper surface of the lower wall 41 and the upper surface of the upper wall 42 that are adhered to each other are ensured to be sufficiently large.

[0038] As described above, Patent Document 3 shows that the processing state at each part of the substrate G is adjusted by making the circumferential height of the straightening wall different. However, the straightening wall in Patent Document 3 is composed of parts arranged side by side. When replacing a part at one location to adjust the distribution of the etching amount of the substrate G, the connection with the adjacent parts on the left and right is released, and a new part is reconnected. That is, when changing a part at one location, the part must be attached and detached at two locations on the left and right, and when changing parts at multiple locations, the number of locations to be attached and detached becomes very large, which increases the labor of the worker. On the other hand, when the upper wall 42 is detachable from the lower wall 41 as in the example of FIG. 4, it is easy to attach and detach only the desired upper wall 42 and shift its position. That is, according to the configuration in which the upper wall 42 is detachable from the lower wall 41, the distribution of the etching amount in the surface of the substrate G can be easily adjusted.

[0039] Another example of the configuration in which the upper wall 42 is detachably attached to the lower wall 41 and the position can be changed is shown in FIG. 5. The lower end of the main surface of the upper wall 42 facing the outer periphery of the straightening wall 4 is extended toward the outer periphery and further extended downward to form a plate-shaped connecting portion 50, which is a first connecting portion. The orientation of the main surface of the connecting portion 50 is the same as the orientation of the main surface of the upper wall 42. Through holes 53 and 54 are provided penetrating the connecting portion 50 and the lower wall 41 in the thickness direction, respectively, and a threaded portion is formed on the peripheral surface (inner wall of the through hole) that forms the through hole 54, for example. The through holes 53 and 54 are overlapped, and a screw 55 is inserted into the through hole 53 and 54 from the outer periphery side of the straightening wall 4 and screwed into the threaded portion on the peripheral surface of the through hole 54, thereby fixing the upper wall 42 to the lower wall 41. Alternatively, a screw portion may be formed on the peripheral surface forming the through hole 53, and a screw 55 may be inserted from the inner peripheral surface side of the flow straightening wall 4 and screwed into the screw portion on the peripheral surface of the through hole 53 to fix the upper wall 42 to the lower wall 41. In this case, it is preferable to provide a counterbore (recess) at the opening of the through hole 54 so that the head of the screw 55 is accommodated so that the head of the screw 55 does not protrude toward the substrate G. The above screwing is releasable, and therefore the upper wall 42 is detachable from the lower wall 41. In the example of FIG. 5, a plurality of through holes 53 are arranged in the horizontal direction and are provided close to each other in the lower wall 41. The position of the upper wall 42 relative to the lower wall 41 can be changed by selecting the through hole 53 into which the screw 55 is inserted from among the plurality of through holes 53.

[0040] Regarding the connection portion connecting the lower wall 41 and the upper wall 42, the above-mentioned connection portion 50 is configured as one piece with the upper wall 42 and separate from the lower wall 41, but it may be configured as a separate portion from each of the upper wall 42 and the lower wall 41, as in the case of connection portion 56 shown in Fig. 6. Regarding connection portion 56, the differences from connection portion 52 will be mainly described. Connection portion 56 is a plate-like member provided so as to straddle from the main surface of upper wall 42 to the main surface of lower wall 41. Note that each of the main surfaces refers to the main surfaces on the side forming the outer circumferential surface of the flow straightening wall 4.

[0041] The connection portion 56 has through holes 53 formed on the upper and lower sides. In addition, not only the lower wall 41 but also the upper wall 42 has through holes 54 corresponding to the through holes 53. The upper through hole 53 is overlapped with the through hole 54 of the upper wall 42, and the lower through hole 53 is overlapped with the through hole 54 of the lower wall 41. As in the example of FIG. 5, a screw 55 is inserted into the overlapped through holes 53 and 54 from the outer peripheral surface side or the inner peripheral surface side of the straightening wall 4. Thereby, the lower wall 41 and the upper wall 42 are fixed to the connection portion 56, respectively. That is, the lower wall 41 and the upper wall 42 are fixed to each other via the connection portion 56. Note that, in FIG. 6, only two through holes 54 are shown aligned horizontally in the upper wall 54, but, for example, more through holes 54 than that may be aligned horizontally. Then, from among the many through holes 54, through holes 54 into which screws 55 are inserted may be selected, thereby adjusting the position of the upper wall 42 in the same manner as in the example shown in Fig. 5. Of the many through holes 54, through holes 54 into which screws 55 are not inserted are blocked by overlapping connection portions 56.

[0042] In the example shown in Fig. 6, the connection portion 56 can be seen as extending from the upper wall 42 toward the lower wall 41, or from the lower wall 41 toward the upper wall 42. Therefore, in the examples shown in Fig. 5 and Fig. 6, one of the upper wall 42 and the lower wall 41 is provided with a connection portion extending toward the other, and this connection portion is connected to the other via a screw. Note that, contrary to the example of Fig. 5, the connection portion 50 may be fixed to the lower wall 41 and extend toward the upper wall 42, and the connection portion 50 may be connected to the upper wall 42 via a screw 55.

[0043] Another example in which the upper wall 42 and the lower wall 41 are detachably fixed to each other via screws is shown in FIG. 7. A plurality of holes 57 are formed in the lower wall 41 at intervals along the circumference of the lower wall 41 and perpendicular to the upper end surface of the lower wall 41. The holes 57 open to the upper surface of the lower wall 41 and have, for example, a threaded portion formed on the circumferential surface. The upper end surface of the upper wall 42 is provided with a through hole 58 in the vertical direction. The upper wall 42 is arranged on the lower wall 41 so that the through hole 58 overlaps with any of the holes 57, and a long screw 59 is inserted from above the upper wall 42 and screwed into the threaded portion of the hole 57, thereby fixing the upper wall 42 to the lower wall 41. After the fixing, the screwing is released, and the hole 57 into which the long screw 59 is inserted is changed and screwed again, so that the position of the upper wall 42 can be changed. It is preferable to close the holes 57 that are not used to fix the upper wall 42 and the lower wall 41 with a cap or the like.

[0044] Incidentally, the upper wall 42 has been shown as an example in which the height is uniform when viewed along the circumference of the lower wall 41, that is, the height of the upper end is uniform. However, the shape is not limited to this, and the upper wall 42 may be configured to have an upper end whose height varies when viewed along the circumference. FIG. 8 shows an example in which such an upper wall 42 is formed in a mountain shape. Therefore, when the upper wall 42 is disposed on the long wall portion 41A, the height of the central portion in the X direction is large, and when the upper wall 42 is disposed on the short wall portion 41B, the height of the central portion in the Y direction is large. In addition, the upper wall 42 may be configured to have a recessed shape as shown in FIG. 9. Therefore, when the upper wall 42 is disposed on the long wall portion 41A, the height of the central portion in the X direction is small, and when the upper wall 42 is disposed on the short wall portion 41B, the height of the central portion in the Y direction is small. By configuring the upper wall 42 to have different heights when viewed along the circumference of the lower wall 41 as in the examples of FIGS. 8 and 9, the gas flow at each portion of the peripheral edge of the substrate G can be finely adjusted, and the uniformity of the processing at the peripheral edge of the substrate G can be improved.

[0045] The arrangement and number of the exhaust ports 14 are not limited to the above-mentioned example. For example, a total of four exhaust ports 14 may be provided, and each may be arranged near each corner of the stage 21. Then, suppose that the positions at the peripheral edge of the substrate G where the etching amount becomes excessively large if the upper wall 42 is not provided become the corners of the substrate G due to such an arrangement of the exhaust ports 14. In that case, instead of the above-mentioned positions, the upper wall 42 may be provided on each of the four corners of the lower wall 41. Therefore, the arrangement of the upper wall 42 is not limited to a position off the corners of the lower wall 41 as shown in FIG. 2, FIG. 3, etc. In addition, since the upper wall 42 is provided in accordance with the region where the etching amount becomes locally large in this way, the number of the upper walls 42 is not limited to eight, and may be provided in accordance with the number of the regions. In addition, although an example in which the present technology is applied to an etching device that performs plasma processing has been shown, the present technology is not limited to being applied to such a device, and may be applied to a film forming device or a substrate processing device in which plasma processing is not performed. Furthermore, the present invention is not limited to the position of the exhaust port 14, but can also be applied to other factors that act from the outer periphery of the stage 21 to affect the flow of the etching gas at the peripheral edge of the substrate G and cause non-uniformity in the etching rate.

[0046] The rectifying wall 4 is provided on the stage 21. Regarding the stage 21, the stage 21 may include other members in addition to a member (mounting surface forming member) forming a mounting surface on which the substrate G is placed. The other members are members that surround the mounting surface forming member and are connected to the mounting surface forming member. For example, in the above-mentioned example, the mounting surface forming member is the lower electrode 22, and the other member is the annular member 23. In that case, the rectifying wall 4 may be provided on the lower electrode 22, which is the mounting surface forming member, or on the annular member 23, which is the other member. As described above, the rectifying wall 4 may rise and fall or rotate with respect to the stage 21. The rectifying wall 4 being provided on the stage 21 means that the rectifying wall 4 is located on the stage 21 at least during processing of the substrate G.

[0047] In the above-mentioned example, the height of the upper end of the lower wall 41 is uniform around the circumference, so that the upper wall 42 can be provided at any position around the circumference. However, the height of the upper end around the circumference is not limited to being uniform in this way, and unevenness may be formed. However, by making the height of the upper end around the circumference uniform, the upper wall 21 can be attached to all positions around the circumference of the lower wall 41. In other words, this is advantageous because there is a high degree of freedom in the attachment position. In addition, the shape of the substrate to be processed is not limited to the rectangular substrate in plan view described above, but may be circular, and in this case, the lower wall 41 may be circular in plan view to match the shape of the substrate.

[0048] It should be noted that the embodiments disclosed herein should be considered to be illustrative and not restrictive in all respects. The above-described embodiments may be omitted, substituted, modified, or combined in various forms without departing from the scope and spirit of the appended claims.

[0049] [Evaluation test] The evaluation test will be described in detail below. In evaluation test 1-1, a straightening wall composed only of the lower wall 41 without the upper wall 42 was used to etch the substrate G, and the amount of etching at each portion was measured. The substrate G used in this evaluation test was provided with a film on which a pattern was formed (hereinafter, referred to as a pattern film) from its center to an area 25 mm away from each of the long and short sides of the substrate G. That is, the peripheral edge of the substrate G was a square, annular area (rectangular frame area) on which the pattern film was not formed, and the width of this annular area was 25 mm. Since the area on which the pattern film was formed was limited in this way, a small piece of 50 mm square cut from the pattern film substrate for measuring the peripheral edge was placed on the peripheral edge of the substrate G, and the above-mentioned etching was performed collectively on the pattern film directly formed on the substrate G and the pattern film of the small piece, and the amount of etching was measured for each pattern film.

[0050] The above-mentioned small pieces are arranged in one of the four regions divided by the imaginary lines L1 and L2 shown in Fig. 3. More specifically, the 50 mm square small pieces are arranged in a region between a position 15 mm away from the long side and a position 30 mm away from the short side of the substrate G. That is, they are arranged in a region between a position 15 mm away from the peripheral edge of the substrate G and a position 30 mm away from the peripheral edge of the substrate G. Therefore, there is a partial overlap between the measurement region measured using the pattern film formed directly on the substrate G and the measurement region measured using the pattern film formed on the small pieces.

[0051] FIG. 10 shows the results of this evaluation test 1-1, and is a schematic representation of the region in which the small pieces are arranged (hereinafter referred to as the 1 / 4 region of the substrate G) among the regions obtained by dividing the substrate G into four by the imaginary lines L1 and L2. The 1 / 4 region of the substrate G corresponds to the lower right region divided by the imaginary lines L1 and L2 in FIG. 3, and therefore the lower right side in FIG. 10 is the corner of the substrate G, and the upper left side is the center of the substrate G. The etching rate obtained by normalizing the measurement results is shown corresponding to the measurement point at which the etching rate was obtained. This etching rate is the value obtained by dividing the etching amount at one measurement point of the substrate G by the average etching amount obtained from all measurement points on the surface of the substrate G, so the larger the normalized etching rate value, the larger the actual etching rate. In FIG. 10, the measurement points are patterned according to the magnitude of the etching rate.

[0052] In the figure, a measurement region using a pattern film directly formed on the substrate G and a measurement region using a small piece of pattern film are separated by a two-dot chain line. An area extending from a position 15 mm away from the center of the substrate G relative to the long side of the substrate G to a position 30 mm away from the center of the substrate G, and an area extending from a position 15 mm away from the center of the substrate G relative to the short side of the substrate G to a position 50 mm away from the center of the substrate G are enclosed by a dashed line as peripheral area E.

[0053] 10, in the outer peripheral region E, between the center in the long side direction (X direction) of the substrate G and the corner of the substrate G, there is a local region with a high etching rate, and this region is indicated as G1. Specifically, in the region G1, the etching rates obtained from the small pieces are 1.08, 1.08, 1.07, 1.09, and 1.06 at positions 15 mm, 18 mm, 20 mm, 25 mm, and 30 mm away from the long side of the substrate G, respectively, and the etching rate obtained from the pattern film directly formed on the substrate G is 1.06. In addition, in the outer peripheral region E, between the center in the short side direction (Y direction) of the substrate G and the corner, there is a local region with a relatively high etching rate, and this region is indicated as G2. Specifically, in region G2, the etching rates obtained from the small pieces are 1.13, 1.09, 1.11, 1.09, and 1.07 at positions 15 mm, 18 mm, 20 mm, 25 mm, and 30 mm away from the long side of substrate G, respectively, and the etching rate obtained from the pattern film directly formed on substrate G is 1.05. Regions G1 and G2 are regions described in the embodiment as having locally large etching amounts at the peripheral edge of substrate G.

[0054] From the measurement results of Evaluation Test 1-1, uniformity, which is an index of variation in the amount of etching, was calculated. This uniformity is expressed as a percentage of the amount of etching (maximum value - minimum value) / (maximum value + minimum value), and the smaller this value is, the more uniform the etching process is. The uniformity in a quarter of the area of ​​substrate G was 13.9%, and the uniformity in the outer peripheral area E of that quarter was 15.1%.

[0055] In evaluation test 1-2, etching was performed in the same manner as in evaluation test 1-1, except that a straightening wall 4 with an upper wall 42 provided at the position described in Figs. 1 to 3 was used, and the amount of etching was measured. Fig. 11 shows the results of evaluation test 1-2, and shows a 1 / 4 region of substrate G as in Fig. 10. As shown in the figure, the etching rates in regions G1 and G2 are lower than those in evaluation test 1-1. Specifically, in region G1, the etching rates obtained from the small pieces were 0.94, 0.94, 0.93, 0.93, and 0.97 at positions 15 mm, 18 mm, 20 mm, 25 mm, and 30 mm away from the long side of substrate G, respectively, and the etching rate obtained from the pattern film formed directly on substrate G was 0.97. In region G2, the etching rates obtained from the small pieces were 1.04, 1.06, 1.03, 0.99, and 1.00 at distances of 15 mm, 18 mm, 20 mm, 25 mm, and 30 mm from the long side of substrate G, respectively, and the etching rate obtained from the pattern film formed directly on substrate G was 0.99.

[0056] In evaluation test 1-2, the uniformity in 1 / 4 of the substrate G was 11.7%, and the uniformity in the outer peripheral region E in 1 / 4 of the substrate was 7.7%, both of which were smaller than the values ​​in evaluation test 1-1. Thus, it was shown that providing the upper wall 42 can reduce the uniformity value in the outer peripheral region E, thereby reducing the uniformity value including the central portion of the substrate G. Therefore, evaluation test 1 demonstrated the effect of providing the upper wall 42 in that it can increase the uniformity of processing over the entire surface of the substrate G. [Explanation of symbols]

[0057] G board 1 Etching equipment 11 Processing vessel 21 Stage 31 Shower Head 41 Lower wall 42 Upper Wall

Claims

1. a processing vessel for storing the substrate; a stage provided in the processing chamber and having a placement area on which the substrate is placed; a gas supply unit that supplies a processing gas for processing a substrate placed in the placement area; an exhaust port for exhausting the inside of the processing vessel; a lower wall provided on the stage so as to surround the substrate and be formed along a periphery of the mounting area; an upper wall that protrudes upward locally around the periphery of the lower wall and is formed separately from the lower wall; A substrate processing apparatus comprising:

2. The substrate is rectangular in plan view, The lower wall includes two first wall portions opposed to each other and two second wall portions adjacent to the first wall portions and opposed to each other, The substrate processing apparatus according to claim 1 , wherein the upper wall is provided so as to locally protrude upward from each of the first wall portions and each of the second wall portions.

3. 3. The substrate processing apparatus according to claim 2, wherein the heights of the upper ends along the periphery of the lower wall are uniform.

4. 4. The substrate processing apparatus according to claim 1, wherein the upper wall is detachable from the lower wall.

5. 5. The substrate processing apparatus according to claim 4, further comprising a first connection portion formed to extend from one of the upper wall and the lower wall to the other and connected to the other by a screw to fix the upper wall and the lower wall to each other.

6. The substrate processing apparatus according to claim 4 , further comprising a second connecting portion that is adhered to each of the upper wall and the lower wall to fix the upper wall and the lower wall to each other.

7. 7. The substrate processing apparatus according to claim 1, wherein the height of the upper wall is constant when viewed along the periphery of the lower wall.

8. 7. The substrate processing apparatus according to claim 1, wherein the height of the upper wall varies along the periphery of the lower wall.

9. The exhaust port opens upward outside the stage, The substrate processing apparatus according to claim 1 , wherein the upper wall is provided so as to separate the placement area from the exhaust port in a plan view.

10. storing the substrate in a processing vessel; placing the substrate on a placement area on a stage provided in the processing chamber; evacuating the processing vessel through an exhaust port; surrounding the substrate on the stage with a bottom wall formed along a periphery of the mounting area; supplying a processing gas from a gas supply unit to process the substrate on the stage; a step of regulating a flow of the process gas from the substrate toward the exhaust port by the lower wall and an upper wall that protrudes upward locally around the periphery of the lower wall and is formed separately from the lower wall; A substrate processing method comprising:

11. The upper wall is 11. The substrate processing method according to claim 10, wherein the upper wall is provided so as to separate a position at a peripheral edge of the substrate where a processing speed is locally high from the exhaust port when the upper wall is not provided.

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