Substrate processing equipment

Abstract

To provide a technique capable of improving adsorptivity of a substrate in heat treatment and improving uniformity of heat treatment.SOLUTION: A heat treatment unit U2 includes a hot plate 20 for mounting a wafer W thereon and heating the mounted wafer W, a plurality of gap members 22 which is formed along a surface 20a of the hot plate 20 on which the wafer W is mounted, supports the wafer W and ensures a gap V between the hot plate 20 and the wafer W, a suction portion 70 for sucking the wafer W to the hot plate 20, and an elevating pin 51 which is provided so as to penetrate the hot plate 20 and elevates the wafer W mounted on the hot plate 20 by raising and lowering. The surface 20a of the hot plate 20 has a recessed region 20d that slopes downward from the outside to the inside.SELECTED DRAWING: Figure 4

Description

Technical Field

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

Background Art

[0002] Patent Document 1 discloses an apparatus that performs a heat treatment while sucking a wafer on a flat hot plate, measures the warpage state of the wafer before the heat treatment, and sets the suction start timing of each suction port for the wafer according to the warpage state of the wafer.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] The present disclosure provides a technique capable of improving the adsorptivity of a substrate in a heat treatment and improving the uniformity of the heat treatment.

Means for Solving the Problems

[0005] A substrate processing apparatus according to one aspect of the present disclosure includes a hot plate that places and heats a substrate, a plurality of gap members formed along the surface of the hot plate on which the substrate is placed, supporting the substrate and securing a gap between the hot plate and the substrate, a suction unit that sucks the substrate toward the hot plate, and a lifting pin provided so as to penetrate the hot plate and configured to lift and lower the substrate placed on the hot plate by lifting and lowering. The surface of the hot plate has a concave region that slopes downward from the outside toward the inside.

Effects of the Invention

[0006] According to the present disclosure, a substrate processing apparatus capable of improving the adsorptivity of a substrate in a heat treatment and improving the uniformity of the heat treatment is provided. [Brief explanation of the drawing]

[0007] [Figure 1] Figure 1 is a schematic perspective view showing an example of a substrate processing system according to an embodiment. [Figure 2] Figure 2 is a schematic side view showing an example of a coating and developing apparatus. [Figure 3] Figure 3 is a schematic diagram showing an example of a heat treatment unit. [Figure 4] Figure 4 is a diagram illustrating the detailed shape of the heating plate. [Figure 5] Figure 5(a) illustrates an example where a convex wafer is placed on a flat hot plate, and Figure 5(b) illustrates an example where a concave wafer is placed on a flat hot plate. [Figure 6] Figure 6 illustrates the arrangement of the control temperature sensors. [Figure 7] Figure 7(a) shows temperature control based on temperature acquired by a control temperature sensor located relatively close to the heating plate, while Figure 7(b) shows temperature control based on temperature acquired by a control temperature sensor located relatively far from the heating plate. [Figure 8] Figure 8 is a schematic diagram showing an example of the configuration of the sealing section. [Figure 9] Figure 9 is a block diagram showing an example of the hardware configuration of a control device. [Figure 10] Figure 10 shows examples of required VAC flow rates for different wafer warpage amounts. [Figure 11] Figures 11(a) and 11(b) show examples of wafer temperature ranges for the heating plate in the comparative example. [Figure 12] Figures 12(a) and 12(b) show examples of wafer temperature ranges for the heating plate according to this embodiment. [Figure 13] Figure 13 illustrates the descent speed of the lifting pin in a modified example. [Figure 14] Figure 14 is a side view of the inspection unit related to a modified example. [Figure 15]Figure 15(a) is a plan view of a modified heating plate, and Figure 15(b) is a cross-sectional view along line bb in Figure 15(a). [Modes for carrying out the invention]

[0008] Several embodiments will be described below with reference to the drawings. In the description, the same elements or elements having the same function will be denoted by the same reference numeral, and redundant descriptions will be omitted.

[0009] [Substrate Processing System] First, the substrate processing system 1 will be described with reference to Figures 1 and 2. The substrate processing system 1 shown in Figure 1 is a system that performs the following processes on a wafer W: formation of a photosensitive film, exposure of the photosensitive film, and development of the photosensitive film. The wafer W to be processed is, for example, a substrate, or a substrate in which a film or circuit has been formed by a predetermined process. The substrate is, as an example, a silicon wafer. The wafer W (substrate) may be circular. The wafer W may also be a glass substrate, a mask substrate, or an FPD (Flat Panel Display). The photosensitive film is, for example, a resist film.

[0010] As shown in Figures 1 and 2, the substrate processing system 1 comprises a coating and developing apparatus 2 (substrate processing apparatus), an exposure apparatus 3, and a control device 100. The exposure apparatus 3 is an apparatus for exposing a resist film (photosensitive coating) formed on a wafer W (substrate). Specifically, the exposure apparatus 3 irradiates the portion of the resist film to be exposed with energy rays by methods such as immersion exposure.

[0011] The coating and developing apparatus 2 applies a resist (chemical solution) to the surface of the wafer W to form a resist film before exposure processing by the exposure apparatus 3, and then develops the resist film after exposure processing. The coating and developing apparatus 2 comprises a carrier block 4, a processing block 5, and an interface block 6.

[0012] The carrier block 4 introduces the wafer W into the coating and developing apparatus 2 and exports the wafer W from the coating and developing apparatus 2. For example, the carrier block 4 can support a plurality of carriers C for the wafer W and incorporates a transfer device A1 including a transfer arm. The carrier C accommodates, for example, a plurality of circular wafers W. The transfer device A1 takes out the wafer W from the carrier C and delivers it to the processing block 5, and receives the wafer W from the processing block 5 and returns it into the carrier C. The processing block 5 has processing modules 11, 12, 13, and 14.

[0013] The processing module 11 incorporates a liquid processing unit U1, a heat treatment unit U2, and a transfer device A3 that transfers the wafer W to these units. The processing module 11 forms a lower layer film on the surface of the wafer W by the liquid processing unit U1 and the heat treatment unit U2. The liquid processing unit U1 applies a processing liquid for forming the lower layer film onto the wafer W. The heat treatment unit U2 performs various heat treatments associated with the formation of the lower layer film.

[0014] The processing module 12 incorporates a liquid processing unit U1, a heat treatment unit U2, and a transfer device A3 that transfers the wafer W to these units. The processing module 12 forms a resist film on the lower layer film by the liquid processing unit U1 and the heat treatment unit U2. The liquid processing unit U! applies a processing liquid for forming the resist film onto the lower layer film. The heat treatment unit U2 performs various heat treatments associated with the formation of the resist film.

[0015] The processing module 13 incorporates a liquid processing unit U1, a heat treatment unit U2, and a transfer device A3 that transfers the wafer W to these units. The processing module 13 forms an upper layer film on the resist film by the liquid processing unit U1 and the heat treatment unit U2. The liquid processing unit U1 applies a processing liquid for forming the upper layer film onto the resist film. The heat treatment unit U2 performs various heat treatments associated with the formation of the upper layer film.

[0016] The processing module 14 incorporates a liquid processing unit U1, a heat processing unit U2, and a transport device A3 for transporting wafers W to these units. The processing module 14 performs development processing and associated heat processing of the exposure-treated resist film using the liquid processing unit U1 and the heat processing unit U2. The liquid processing unit U1 supplies a developer solution onto the surface of the exposed wafer W, and then washes it off with a rinsing solution to form a resist pattern (performs the development processing of the resist film). The heat processing unit U2 performs various heat processing associated with the development processing. Specific examples of heat processing include heat treatment before development processing (PEB: Post Exposure Bake) and heat treatment after development processing (PB: Post Bake).

[0017] A shelf unit U10 is provided on the carrier block 4 side within the processing block 5. The shelf unit U10 is divided into multiple cells arranged vertically. A transport device A7, including a lifting arm, is provided near the shelf unit U10. The transport device A7 raises and lowers the wafer W between the cells of the shelf unit U10.

[0018] A shelf unit U11 is provided on the interface block 6 side within the processing block 5. The shelf unit U11 is divided into multiple cells arranged vertically.

[0019] Interface block 6 handles the transfer of wafers W to and from the exposure apparatus 3. For example, interface block 6 incorporates a transport device A8 including a transfer arm, which is connected to the exposure apparatus 3. Transport device A8 transfers wafers W placed on shelf unit U11 to the exposure apparatus 3. Transport device A8 receives wafers W from the exposure apparatus 3 and returns them to shelf unit U11.

[0020] The control device 100 is configured to partially and entirely control the coating and developing apparatus 2. The control device 100 controls the coating and developing apparatus 2 to perform the coating and developing process in the following procedure, for example: First, the control device 100 controls the transport device A1 to transport the wafer W in the carrier C to the shelf unit U10, and then controls the transport device A7 to place the wafer W into a cell for the processing module 11.

[0021] Next, the control device 100 controls the transport device A3 to transport the wafer W from the shelf unit U10 to the liquid treatment unit U1 and the heat treatment unit U2 in the processing module 11. The control device 100 also controls the liquid treatment unit U1 and the heat treatment unit U2 to form an underlayer film on the surface of the wafer W. After that, the control device 100 controls the transport device A3 to return the wafer W with the underlayer film formed on it back to the shelf unit U10, and controls the transport device A7 to place the wafer W into a cell for the processing module 12.

[0022] Next, the control device 100 controls the transport device A3 to transport the wafer W from the shelf unit U10 to the liquid treatment unit U1 and the heat treatment unit U2 in the processing module 12. The control device 100 also controls the liquid treatment unit U1 and the heat treatment unit U2 to form a resist film on the underlying film of the wafer W. After that, the control device 100 controls the transport device A3 to return the wafer W to the shelf unit U10 and controls the transport device A7 to place the wafer W into a cell for the processing module 13.

[0023] Next, the control device 100 controls the transport device A3 to transport the wafer W from the shelf unit U10 to each unit in the processing module 13. The control device 100 also controls the liquid processing unit U1 and the heat processing unit U2 to form an upper layer film on the resist film of the wafer W. After that, the control device 100 controls the transport device A3 to transport the wafer W to the shelf unit U11.

[0024] Next, the control device 100 controls the transport device A8 to send the wafer W from the shelf unit U11 to the exposure apparatus 3. Subsequently, the control device 100 controls the transport device A8 to receive the exposed wafer W from the exposure apparatus 3 and place it in the cell for the processing module 14 in the shelf unit U11.

[0025] Next, the control device 100 controls the transport device A3 to transport the wafer W from the shelf unit U11 to each unit in the processing module 14, and controls the liquid processing unit U1 and the heat processing unit U2 to perform development processing on the resist film of the wafer W. After that, the control device 100 controls the transport device A3 to return the wafer W to the shelf unit U10, and controls the transport devices A7 and A1 to return the wafer W to the carrier C.

[0026] With the above steps, the coating and developing process for one wafer W is completed. The control device 100 then instructs the coating and developing apparatus 2 to perform the same coating and developing process for each of the subsequent wafers W. Note that the specific configuration of the coating and developing apparatus 2 is not limited to the configuration exemplified above. The coating and developing apparatus 2 can be any apparatus that includes a unit for heat treatment.

[0027] <Heat Treatment Unit> Next, an example of the heat treatment unit U2 will be described in detail with reference to Figures 3 to 8. The heat treatment unit U2 is configured to perform a heat treatment on the wafer W that includes both heating and cooling. In this embodiment, the configuration related to the heating treatment of the heat treatment unit U2 will be described, and the configuration related to the cooling treatment will be omitted. That is, in Figure 3 and other figures, the diagram of the configuration related to the cooling treatment of the heat treatment unit U2 is omitted.

[0028] As shown in Figure 3, the heat treatment unit U2 comprises a heating plate 20, a plurality of gap members 22, a support base 30, a plurality of heating plate temperature sensors 40, a lifting mechanism 50, a suction unit 70, and a control device 100.

[0029] The heating plate 20 supports the wafer W and heats the wafer W. The heating plate 20 receives heat from the heater 21 (heating mechanism) and maintains a high temperature through solid heat conduction. The heating plate 20 may be made of a material containing, for example, silicon carbide. The heating plate 20 is disc-shaped and contains multiple heaters 21. The heating plate 20 has an area equal to or greater than that of the wafer W when viewed from above. Multiple through holes 20z are formed in the thickness direction of the heating plate 20. The multiple through holes 20z are provided in correspondence with multiple lifting pins 51 (described later) and serve as passage paths for the lifting pins 51 when they move up and down.

[0030] Multiple gap members 22 are formed along the surface 20a on the heating plate 20 on which the wafer W is placed, and are proximity pins that support the wafer W and secure an air gap V between the heating plate 20 and the wafer W. Multiple gap members 22 are scattered along the surface 20a of the heating plate 20. Multiple gap members 22 may have a common height from the surface 20a of the heating plate 20 to the tip that contacts the wafer W.

[0031] Although Figure 3 shows the heating plate 20 as a flat plate, in reality, the heating plate 20 is formed in a concave shape that slopes downward from the outside to the inside (see Figure 4). Figure 4 is a diagram illustrating the details of the shape of the heating plate 20.

[0032] As shown in Figure 4, the surface 20a on which the wafer W is placed on the heating plate 20 has a concave region 20d that slopes downward from the outer edge (outside) to the center (inside). In the heating plate 20 according to this embodiment, substantially the entire surface 20a is a concave region 20d, with the outer edge portion 20e being the region that protrudes most upward and the central portion 20c being the region that protrudes most downward. That is, in the heating plate 20, the region that protrudes most downward in the concave region 20d is the region (central portion 20c) that faces the central portion Wc of the wafer W when the wafer W is placed on it. More specifically, the outermost edge of the surface 20a of the heating plate 20 (further outside the outer edge portion 20e of the concave region 20d) is a flat portion 20f. Alternatively, the curved surface of the concave region 20d may be continuous to the outermost edge of the heating plate 20 without a flat portion 20f. With such a configuration, the heating effect at the outer edge of the wafer W can be improved. The shape of the surface 20a on which the concave region 20d is formed is, for example, a sphere (curved surface), and its curvature may or may not be constant. If the curvature of the concave region 20d is not constant, for example, the curvature on the inside of the concave region 20d may be greater than the curvature on the outside (i.e., the inside may be deeper). With such a configuration, when the warping of the wafer W is not uniform, it becomes easier to create a state in which the gap between the wafer W and the hot plate 20 is narrower on the outside than on the inside when suction is performed, making it easier to suction wafers W with various types of warping. In other words, the robustness of suction to the warping of the wafer W can be improved.

[0033] In the example shown in Figure 4, the wafer W is a concave wafer (a substrate with positive curvature) in which the central portion Wc protrudes downward compared to the outer edge portion We. The wafer W placed on the heating plate 20 can be not only a concave wafer, but also a flat wafer or a convex wafer (a substrate with negative curvature) in which the central portion Wc protrudes upward compared to the outer edge portion We. Considering that wafers of various shapes like these may be placed on the heating plate 20, it is preferable to use a heating plate 20 having the downwardly sloping concave region 20d described above. The reason for this will be explained with reference to Figure 5.

[0034] Figure 5(a) illustrates an example in which a convex wafer W is placed on a flat plate-shaped heating plate 200, and Figure 5(b) illustrates an example in which a concave wafer W is placed on a flat plate-shaped heating plate 200. As shown in Figure 5(a), for a convex wafer W, even with a flat plate-shaped heating plate 200, the outer edge portion We is placed on the gap member 22 on the outer edge side of the heating plate 200. In this configuration, where the outer edge portion We of the wafer W is appropriately placed on the gap member 22, the wafer W acts as a lid over the adsorption area, and the wafer W can be appropriately adsorbed in the direction of the heating plate 200 by the suction of the suction unit 70. For both convex wafers W and flat wafers W, even with a heating plate 20 having a concave region 20d according to this embodiment (see Figure 4), the outer edge portion We of the wafer W can be appropriately placed on the gap member 22 on the outer edge side. This allows the wafer W to be appropriately adsorbed in the direction of the heating plate 200 by the suction of the suction unit 70.

[0035] On the other hand, as shown in Figure 5(b), with respect to a concave wafer W, the outer edge portion We is not placed on the gap member 22 on the outer edge side of the flat heating plate 200 and remains floating. In this case, it is not possible to form a state where the wafer W acts as a lid, making it easier for air to be drawn in from the outer edge portion We side, making it difficult to achieve airtightness, and thus the adsorption of the wafer W to the heating plate 200 becomes low. Thus, while the shape of the heating plate is not much of a problem from the viewpoint of the adsorption of the wafer W for convex wafers W and flat wafers W, the adsorption of the wafer W cannot be guaranteed with a flat heating plate 200 for concave wafers W. For this reason, in situations where wafers W of various shapes may be placed, it is preferable to make the shape of the heating plate a shape that improves the adsorption of concave wafers W. As described above, when placing a concave wafer W onto a hot plate, the outer edge portion We is not placed on the gap member 22 and remains floating, which is a problem. Therefore, the hot plate 20 described above is used as a hot plate that ensures the outer edge portion We is placed on the gap member 22. In other words, by using a hot plate 20 having a concave region 20d that slopes downward from the outer edge towards the center, the shape of the concave wafer W and the shape of the hot plate 20 can be more easily matched, and the outer edge portion We of the wafer W can be properly placed on the gap member 22. This improves the adhesion of the concave wafer W to the hot plate 20.

[0036] The depth d1 of the concave region 20d in the heating plate 20 is set to be at least greater than the amount of warpage of the concave wafer W. As shown in Figure 4, the depth d1 is the length in the height direction from the flat portion 20f, which is the reference plane, to the central portion 20c. The amount of warpage of the wafer W is the length in the height direction from the outer edge portion We of the wafer W to the central portion Wc of the wafer W.

[0037] The shape of the concave region 20d of the heating plate 20 is determined, for example, as follows. Let's assume that a concave wafer W has a diameter of 300 mm and a curvature of 1000 μm. In this case, the radius of curvature of the wafer W is calculated to be 11250.5 mm by the square root theorem. Although deformation of the wafer W occurs due to differences in linear expansion when the film is uniformly deposited on the wafer W, the above relationship holds true when the cross-sectional shape of the wafer W is measured. Based on the radius of curvature of the wafer W, the radius of curvature of the concave region 20d of the heating plate 20 is determined. Specifically, the radius of curvature of the concave region 20d is calculated by adding the thickness of the wafer W and the height protruding from the surface 20a of the gap member 22 to the radius of curvature of the wafer W (11250.5 mm).

[0038] Furthermore, the depth d1 and diameter Φ of the concave region 20d of the heating plate 20 are set to a size that takes into account the wafer W size and positional deviations during robot transport, etc. Specifically, considering a transport error of about 2 mm, the depth d1 of the concave region 20d may be about 1 mm and the diameter Φ may be about 304 mm. Even if the transport error described above occurs, the impact on wafer temperature uniformity during heat treatment is small.

[0039] The concave region 20d of the hot plate 20, whose shape is determined as described above, can be processed, for example, by a rotary grinding machine. If process defects due to minute particles generated from the surface after processing are expected, the risk of particle shedding can be reduced by performing brush polishing or annealing treatment.

[0040] Returning to Figure 3, the suction unit 70 applies a suction force to the wafer W, thereby drawing the wafer W toward the hot plate 20. The suction unit 70 applies a suction force to multiple areas on the back surface of the wafer W. The suction unit 70 includes a suction means 71 and multiple pipes 72.

[0041] The suction means 71 is a mechanism that draws up gas by the action of pressure. Each of the multiple pipes 72 has one end connected to the suction means 71 and the other end reaching the adsorption holes 20x (the part facing the wafer W) formed on the surface 20a of the hot plate 20.

[0042] The support base 30 comprises a base plate 31 and a peripheral wall 32 (support member). The support base 30 may be made of a material including, for example, stainless steel. The peripheral wall 32 is provided along the periphery of the base plate 31 and supports the outer periphery of the heating plate 20. The base plate 31 faces the heating plate 20 and supports the heating plate 20 from below via the peripheral wall 32. When the peripheral wall 32 supports the heating plate 20, a cavity 33 is formed inside the support base 30. The base plate 31 has a plurality of path holes 31z through which the lifting pins 51 (described later) pass. The plurality of path holes 31z are provided corresponding to the plurality of lifting pins 51 and serve as the passage paths for the lifting pins 51 when they move up and down.

[0043] Multiple hot plate temperature sensors 40 are each installed at different locations inside the hot plate 20. The multiple hot plate temperature sensors 40 measure the temperature near the heater 21 and transmit the measurement results to the control device 100.

[0044] In addition to the multiple hot plate temperature sensors 40, control temperature sensors 140 may be provided inside the hot plate 20 to correspond to different positions on the wafer W. Figure 6 is a diagram illustrating the arrangement of the multiple control temperature sensors 140. As shown in Figure 6, it is preferable that the multiple control temperature sensors 140 provided inside the hot plate 20 be spaced as close as possible to the surface 20a of the hot plate 20. Specifically, it is preferable that the distance of the control temperature sensors 140 from the surface 20a be uniformly set to about 1 mm to 3 mm. Furthermore, the multiple control temperature sensors 140 are provided such that the length d2 in the height direction (vertical direction) from their upper end 140a (tip) to the surface 20a of the hot plate 20 is equal to that of the other.

[0045] Figure 7(a) shows temperature control based on temperature acquired by a control temperature sensor 140 located relatively close to the surface 20a of the hot plate 20, while Figure 7(b) shows temperature control based on temperature acquired by a control temperature sensor 140 located further away. In Figures 7(a) and 7(b), the horizontal axis represents time, and the vertical axis represents the temperature acquired by the control temperature sensor 140. As shown in Figures 7(a) and 7(b), the closer the control temperature sensor 140 is to the surface 20a, the faster it can acquire the temporary temperature drop after the wafer W is mounted on the hot plate 20. This allows for earlier start of heating control of the heater 21, improving control responsiveness and enabling early optimization of the heat treatment temperature. Furthermore, if, for example, the distances of multiple control temperature sensors 140 from the surface 20a are different, the time it takes for the heat treatment temperature to be optimized will differ, as shown in Figures 7(a) and 7(b). In this case, the heat treatment method will differ for each region of the wafer W corresponding to each control temperature sensor 140. In this case, the uniformity of the heat treatment of the wafer W may be impaired. In this regard, as described above, by making the height (vertical) length d2 of the multiple control temperature sensors 140 up to the surface 20a equal to each other, the uniformity of the heat treatment of the wafer W can be improved. In this way, the temperature of the hot plate 20 is controlled based on the temperature acquired by the control temperature sensor 140, which is closer to the surface 20a of the hot plate 20 than the hot plate temperature sensor 40 located near the heater 21, and whose distance from the surface 20a is controlled to a predetermined value. This makes it possible to perform heat treatment that is more suitable for the temperature distribution state of the wafer W. Furthermore, even in configurations where the distance from the heater 21 to the surface 20a differs depending on the position, such as when the surface 20a has a curved surface or steps and the heater 21 is installed approximately horizontally, this control method is preferable as a method suitable for the temperature distribution of the wafer W.

[0046] Returning to Figure 3, the lifting mechanism 50 has a plurality (for example, three) of lifting pins 51 and a drive unit 52. The lifting pins 51 move up and down by passing through the path holes 31z in the base plate 31 and the through holes 20z in the heating plate 20. The upper part of the lifting pin 51 protrudes above the heating plate 20 as the lifting pin 51 rises and is retracted into the heating plate 20 as the lifting pin 51 lowers. The drive unit 52 incorporates a drive source such as a motor or air cylinder and moves the lifting pin 51 up and down. The lifting mechanism 50 moves the wafer W on the heating plate 20 up and down by moving the lifting pin 51 up and down. Here, from the viewpoint of improving the suction effect when the suction unit 70 sucks the wafer W toward the heating plate 20, it is preferable that the path holes 31z of the lifting pins 51 etc. are closed to the space below the base plate 31. Below, with reference to Figure 8, an example of the configuration of the seal part related to the closing of the path holes 31z etc. will be described.

[0047] Figure 8 is a schematic diagram showing an example of the configuration of the seal section. Note that in Figure 8, the concave region 20d of the heating plate 20 and other parts are omitted from the illustration. As shown in Figure 8, the heat treatment unit U2 has an upper seal section 91 and a lower seal section 92 as the configuration of the seal section. The upper seal section 91 is made of a cylindrical insulating material and is provided so as to be in contact with the surface of the heating plate 20 opposite to the surface 20a (i.e., the bottom surface). The upper seal section 91 is provided so as to surround the lifting pin 51. The upper seal section 91 is elastic and is made of, for example, resin or rubber. Note that a heat-generating resistor 93 may be provided over substantially the entire area of ​​the bottom surface of the heating plate 20.

[0048] The lower seal portion 92 is configured to seal the internal space of the path hole 31z of the base plate 31 and the internal space of the upper seal portion 91 from the space below the base plate 31. The lower seal portion 92 is made of, for example, polyimide or PEEK. As shown in Figure 8, the lower seal portion 92 is provided, for example, on the lower surface of the base plate 31. By positioning the lower seal portion 92 below the base plate 31, the heating effect on the wafer W, which would be a problem if the lower seal portion 92 were located above it while heated, is suppressed. Furthermore, by keeping the lower seal portion 92 away from the heat source, the durability of the lower seal portion 92 can be improved, and the maintainability of the lower seal portion 92 can also be improved. Note that the lower seal portion 92 may be provided inside the base plate 31.

[0049] If an elastic material is not used for the upper seal portion 91, a spring may be further provided between the upper seal portion 91 and the lower seal portion 92 to press the upper seal portion 91 from below. Such a spring may be provided, for example, on a base on the base plate 31.

[0050] The control device 100 controls the heater 21 based on the temperature detected by the multiple control temperature sensors 140, controls the drive unit 52 of the lifting mechanism 50, and controls the transport device A3 to transport the wafer W from the hot plate 20. The control device 100 also controls the suction process by the suction means 71, and so on.

[0051] The control device 100 is comprised of one or more control computers. The control device 100 has, for example, the circuit 120 shown in Figure 9. The circuit 120 includes one or more processors 122, a memory 124, a storage 126, an input / output port 128, and a timer 132. The storage 126 has a storage medium that can be read by the computer, such as a hard disk. The storage medium stores a program that causes the control device 100 to execute the substrate processing method described later. The storage medium may be a removable medium such as a non-volatile semiconductor memory, a magnetic disk, or an optical disk.

[0052] Memory 124 temporarily stores the program loaded from the storage medium of storage 126 and the calculation results by processor 122. Processor 122 works in cooperation with memory 124 to execute the above program. Input / output port 128 inputs and outputs electrical signals to and from liquid treatment unit U1, heat treatment unit U2, etc., according to commands from processor 122. Timer 132 measures elapsed time, for example, by counting reference pulses of a fixed period.

[0053] [Effect] Generally, a flat heating plate 200, as shown in Figures 5(a) and 5(b), is used as the heating plate. With such a heating plate 200, especially when a concave wafer W (see Figure 5(b)) is used in which the inner region protrudes downward compared to the outer region, it is difficult to properly adsorb the outer region of the wafer W even when the wafer W is attracted by the suction part 70. Because the outer region of the concave wafer W is floating (see Figure 5(b)), it is easy to draw in air and difficult to achieve airtightness. For this reason, even when compared to a convex substrate (see Figure 5(a)) in which the inner region protrudes upward, the adsorption to the heating plate 200 is lower.

[0054] Figure 10 shows examples of the required VAC flow rate (vacuum flow rate of the suction section 70) for each wafer warp amount. In Figure 10, the horizontal axis represents the wafer warp amount, and the vertical axis represents the vacuum flow rate required to correct the warp. In Figure 10, the solid line represents the vacuum flow rate for each warp amount for a convex wafer W, and the dashed line represents the vacuum flow rate for each warp amount for a concave wafer W. As shown in Figure 10, the vacuum flow rate is particularly high for concave wafers W. For example, for a wafer W with a warp of 1000 μm, the vacuum flow rate is about 50 times higher than that of a wafer W with a warp of about 200 μm. Increasing the vacuum flow rate in this way to improve the adsorption of wafer W goes against the direction of a sustainable society and is not a good idea. Furthermore, an increase in vacuum flow rate raises concerns about the occurrence of localized cool spots in the inlet area and the generation of scratches and particles on the back surface of wafer W due to increased adsorption pressure. Therefore, there is a need for means other than increasing the vacuum flow rate to improve the adsorption of the concave wafer W to the hot plate.

[0055] In this regard, in the heat treatment unit U2 according to this embodiment, a concave region 20d is formed on the heat plate 20 that slopes downward from the outside to the inside, making it easy to match the shape of the concave wafer W with the shape of the heat plate 20 (specifically the concave region 20d of the heat plate 20). With this configuration, when the wafer W is sucked up by the suction unit 70, the outer region of the concave wafer W can also be appropriately adsorbed onto the heat plate 20. By appropriately adsorbing the wafer W onto the heat plate 20, the wafer W can be appropriately supported by the gap member 22, and heat treatment can be performed uniformly on the substrate regardless of the region. As described above, the heat treatment unit U2 according to this embodiment can improve the adsorption of the wafer W during heat treatment and improve the uniformity of the heat treatment.

[0056] The effect of improving the uniformity of the heat treatment will be explained in comparison with the heat plate 200 of the comparative example. Figures 11(a) and 11(b) show the wafer temperature range for the heat plate 200 of the comparative example. Figures 12(a) and 12(b) show the wafer temperature range for the heat plate 20 according to this embodiment. The wafer temperature range here refers to information about the temperature range between multiple positions obtained as a result of evaluation by attaching temperature sensors to multiple different positions on the surface 20a of the wafer W. In Figures 11(a) and 12(a), the actual temperature difference value is shown as the wafer temperature range, and in Figures 11(b) and 12(b), the degree of temperature difference is shown as a percentage. A degree of temperature difference of 0% indicates that there is no temperature difference at all. In Figures 11(b) and 12(b), the horizontal axis shows the temperature transition when the wafer W is heated, and the vertical axis shows the wafer temperature and the wafer temperature range. Furthermore, in Figures 11(b) and 12(b), the solid line shows the temperature near the center of the wafer W, the dashed line shows the temperature near the outer edge (periphery) of the wafer W, and the dashed line shows the wafer temperature range. The temperatures shown in Figure 11 and Figure 12 (described later) were measured by attaching thermocouples (not shown) to a total of five locations: the center of the wafer W and four locations on the outer edge, each 90 degrees apart from the center. The temperature shown by the solid line is the temperature obtained by the thermocouple at the center, and the temperature shown by the dashed line is the average of the temperatures obtained by the thermocouples at the four outer edge locations. A concave wafer with a warp of 1000 μm was used as the wafer W.

[0057] As shown in Figure 11(a), in the comparative example, the temperature difference between the temperature near the center of the wafer W and the temperature near the outer edge of the wafer W was 62.4°C during the transient state. In the steady state (for example, after 120 seconds), the temperature difference was 6.5°C. Furthermore, as shown in Figure 11(b), even after 120 seconds, the wafer temperature range (the degree of temperature difference between the center and the outer edge) did not reach 0%. Thus, in the comparative example, the temperature difference between the inside and outside of the wafer W was large, and even with a long heating time, an in-plane temperature difference occurred, meaning that the uniformity of the heat treatment could not be achieved.

[0058] In contrast, as shown in Figure 12(a), in the heating plate 20 according to this embodiment, the temperature range obtained by providing control temperature sensors 140 at multiple positions on the wafer W, as described above, is 0.5°C. As is clear from this, the temperature difference is improved by about 125 times compared to the heating plate 200 according to the comparative example. Furthermore, in a steady state (for example, after 60 seconds), the above temperature difference is 0.1°C, which is an improvement of about 65 times compared to the heating plate 200 according to the comparative example. And, as shown in Figure 12(b), the wafer temperature range (the degree of temperature difference between the center and the outer edge) is always around 0% from an early stage. As described above, in the heating plate 20 according to this embodiment, the temperature difference between the inside and outside of the wafer W is kept small from an early stage, so it can be said that the uniformity of the heat treatment is improved.

[0059] The most downwardly protruding region in the concave region 20d may face the central portion Wc of the wafer W when the wafer W is placed on it. With this configuration, it becomes easier to match the shape of the heating plate 20 to the shape of the concave wafer W, thereby improving the adsorption of the wafer W.

[0060] The height of the multiple gap members 22 from the surface 20a of the provided heating plate 20 to the tip that contacts the wafer W may be common to one another. With such a configuration, it is possible to prevent the shape consistency between the concave wafer W and the heating plate 20 from being hindered by the influence of the gap members 22.

[0061] The heat treatment unit U2 further includes a plurality of control temperature sensors 140, each positioned inside the wafer W to correspond to a different location on the wafer W, for measuring the temperature used to control the heater 21. The plurality of control temperature sensors 140 may be positioned such that their lengths in the height direction from their tips to the surface 20a of the heating plate 20 are equal. With this configuration, the temperature used to control the heater 21 is obtained under the same conditions (the same distance from the surface 20a of the heating plate 20) for different locations on the wafer W, thereby improving the uniformity of the heat treatment of the wafer W.

[0062] The heat treatment unit U2 supports the hot plate 20 from below via a peripheral wall 32 and includes a base plate 31 having a path hole 31z through which the lifting pin 51 passes. The heat treatment unit U2 also includes an upper seal portion 91 made of a cylindrical insulating material that contacts the lower surface of the hot plate 20, which is the surface opposite to the surface 20a. Furthermore, the heat treatment unit U2 includes a lower seal portion 92 that closes the internal space of the path hole 31z of the base plate 31 and the internal space of the upper seal portion 91 to the space below the base plate 31. In this way, the lower seal portion 92 closes the internal space of the path hole 31z (the hole through which the lifting pin 51 passes) of the base plate 31 to the space below the base plate 31. This improves the suction effect (vacuum straightening effect of warped wafers) when the suction portion 70 sucks the wafer W toward the hot plate 20. Here, if the only goal is to achieve the aforementioned sealing effect, it is conceivable to construct the sealing portion as a single component rather than dividing it into an upper sealing portion 91 and a lower sealing portion 92. However, if the sealing portion is constructed as a single component, for example, if the sealing portion is located close to the heating plate 20, it is conceivable that the sealing portion will deteriorate prematurely due to thermal degradation. In this embodiment, the sealing portion is divided into an upper sealing portion 91 and a lower sealing portion 92, and the upper sealing portion 91, made of an insulating material that does not interfere with the heat treatment of the heating plate 20, is provided at the location that contacts the heating plate 20. Furthermore, the lower sealing portion 92 is provided at a location away from the heating plate 20 (a location that is not affected by the heat treatment). This makes it possible to properly perform the heat treatment by the heating plate 20 while avoiding premature deterioration of the sealing portion.

[0063] The lower sealing portion 92 may be provided inside the base plate 31 or on the lower surface of the base plate 31. With this configuration, the lower sealing portion 92 can reliably seal the internal space of the path hole 31z of the base plate 31 from the space below the base plate 31.

[0064] The upper seal portion 91 may be elastic. With this configuration, it is possible to improve the contact between the upper seal portion 91 and the heating plate 20 while allowing a certain degree of freedom in the vertical direction of the position of the upper seal portion 91.

[0065] Although various exemplary embodiments have been described above, the invention is not limited to the exemplary embodiments described above, and various additions, omissions, substitutions, and modifications may be made. Furthermore, it is possible to combine elements from different embodiments to form other embodiments.

[0066] For example, in a configuration where the control device 100 controls the drive unit 52 so that the lifting pin 51 moves up and down, the control device 100 may control the drive unit 52 so that the descent speed of the lifting pin 51 changes during its descent.

[0067] Figure 13 illustrates the descent speed of the lifting pin 51 in a modified example. Figure 13 shows an example of the speed of the lifting pin 51 during its descent. In the example shown in Figure 13, the lifting pin 51 descends at a speed of 30 mm / s from the starting position 600 (the UP completion position of the lifting pin 51) to the pause position 601. After the descent is stopped for a predetermined time at the pause position 601, the lifting pin 51 descends at a speed of 2 mm / s from the pause position 601 to the gap lower position 602, which is below the tip of the gap member 22. In this case, the wafer W is placed on the gap member 22 at a descent speed of 2 mm / s. Finally, the lifting pin 51 descends at a speed of 10 mm / s from the gap lower position 602 to the end position 603 (the DOWN completion position of the lifting pin 51).

[0068] In other words, during the descent operation, the control device 100 controls the drive unit 52 so that the lifting pin 51 descends at a predetermined first speed (for example, 30 mm / s) up to a predetermined first height (the temporary stop position 601 described above). Furthermore, when descending further from the first height, the control device 100 controls the drive unit 52 so that the lifting pin 51 descends at a second speed (for example, 2 mm / s) that is slower than the first speed.

[0069] The control device 100 then controls the drive unit 52 so that, during the descent operation, the lifting pin 51, once it reaches a predetermined first height (the temporary stop position 601 described above), stops without descending for a predetermined time.

[0070] The control by the control device 100 described above is intended to suppress large deformation of the wafer W immediately after it is mounted on the heating plate 20. Such large deformation of the wafer W occurs, for example, when only the edge portion (outer edge) of the wafer W is extremely heated, causing a change in the balance of the surface tension of the wafer W due to partial expansion of the wafer W. For example, if the wafer W is convex, the edge portion of the wafer W tends to heat up first, making the large deformation described above more likely to occur.

[0071] The control device 100 controls the drive unit 52 so that the descent speed after reaching the first height is slower than the descent speed to reach the first height. This suppresses the rapid heating of the edges of the convex wafer W when it is mounted on the heating plate 20. As a result, it is possible to suppress the large deformation of the wafer W that can become a problem when the edges of the wafer W are excessively heated.

[0072] Furthermore, the control device 100 controls the drive unit 52 so that the lifting pin 51 stops for a predetermined time at a predetermined first height. This suppresses the rapid heating of the edges of the convex wafer W when it is mounted on the heating plate 20. As a result, large deformation of the wafer W can be more effectively suppressed.

[0073] The control device 100 may determine the first height described above based on the warpage data of the wafer W. In this case, the substrate processing apparatus may further include an inspection unit U3 (see Figure 14) having a peripheral imaging subunit 400 (measurement unit) for measuring the warpage data of the wafer W.

[0074] Figure 14 is a side view of the inspection unit U3 according to a modified example. The inspection unit U3 shown in Figure 14 measures the amount of warpage data of the wafer W. First, the control device 100 controls each part of the substrate processing apparatus to transport the wafer W to the inspection unit U3. Next, the control device 100 controls the rotating holding subunit 900 to hold the wafer W on the holding base 901. Then, the control device 100 controls the rotating holding subunit 900 so that the actuator 903 moves the holding base 901 along the guide rail 904 to a predetermined imaging position.

[0075] Next, the control device 100 controls the rotation holding subunit 900 to rotate the holding base 901 using the actuator 903. This causes the wafer W to rotate. In this state, the control device 100 controls the peripheral imaging subunit 400 to turn on the light source of the illumination module 420 and perform imaging with the camera 410. As a result, the entire circumference of the wafer W edge is imaged. This image of the wafer W edge is warp amount data for determining the amount of warp of the wafer W.

[0076] The control device 100 calculates a profile line of the wafer W based on the captured image of the wafer W's edge. Specifically, the control device 100 distinguishes the upper and lower edges of the wafer W's edge from the captured image, for example, based on the contrast difference. The control device 100 then calculates a line passing through the midpoint between the upper and lower edges as the profile line. The control device 100 subtracts the profile line of a reference wafer (a wafer with a known amount of warpage) from the calculated profile line to calculate the amount of warpage of the wafer W.

[0077] The control device 100 then determines the first height described above, taking into account the amount of warpage of the wafer W calculated based on the warpage data. In this way, by determining the first height, which is the point of change in velocity, while taking into account the actual amount of warpage of the wafer W, it is possible to more appropriately suppress the rapid heating of the edges of the wafer W, taking into account the actual shape of the wafer W.

[0078] Furthermore, the wafer warpage data of W does not necessarily have to be measured by the inspection unit U3. The wafer warpage data of W may be data that has been measured in advance by another device and stored in the substrate processing device.

[0079] Figure 15(a) is a plan view of the heating plate 520 according to a further modification, and Figure 15(b) is a cross-sectional view along the line bb in Figure 15(a). Also, as shown in Figures 15(a) and 15(b), the surface height of the outer peripheral region 652 of the heating plate 520 may be lower than the surface height of the inner region 651. With this configuration, when a convex wafer W is placed on the heating plate 520, the collision of the edge portion of the wafer W with the outer peripheral region 652 of the heating plate 520 and the rapid heating of the edge portion of the wafer W are suppressed, and large deformation of the wafer W can be suppressed.

[0080] The difference in surface height between the outer edge region 652 and the inner region 651 described above may be less than 0.2 mm (for example, about 0.1 mm). When a flat wafer W without irregularities is placed on the heating plate 520, if the difference in surface height between the outer edge region 652 and the inner region 651 is large, there is a risk that the heat treatment will not be performed properly. In this regard, by making the difference in surface height between the outer edge region 652 and the inner region 651 less than 0.2 mm, the heat treatment can be performed properly even when a flat wafer W is placed on the heating plate 520.

[0081] Furthermore, as shown in Figure 15(a), a gap member may be provided, which consists of fixing pins 722 that support the wafer W and are located near the boundary between the outer peripheral region 652 and the inner region 651. In the example shown in Figure 15(a), 24 fixing pins 722 are provided around the entire circumference near the boundary. By providing the fixing pins 722 near the boundary between the outer peripheral region 652 and the inner region 651 in this way, collisions between the edge portion of the convex wafer W and the outer peripheral region 652 can be more effectively suppressed.

[0082] Furthermore, the surface height of the outer peripheral region 652 may be constant (a constant height without any variations in height) throughout the entire region. This allows for proper heat treatment of the wafer W edges.

[0083] Furthermore, as shown in Figures 15(a) and 15(b), the outer peripheral region 652 may be further provided with fixing pins 723 that support the wafer W as gap members. This makes it possible to more effectively suppress the collision of the convex edge portion of the wafer W with the outer peripheral region 652. Note that, as shown in Figure 15(b), the height of the fixing pins 723 may be higher than the region 652 and lower than the inner region 651.

[0084] Herein, various exemplary embodiments included in this disclosure are described in [E1] to [E16] below.

[0085] [E1] The substrate processing apparatus comprises a heating plate on which a substrate is placed and which heats the placed substrate, and a plurality of gap members formed along the surface on which the substrate is placed on the heating plate, supporting the substrate and ensuring an air gap between the heating plate and the substrate. Furthermore, the substrate processing apparatus comprises a suction unit that draws the substrate toward the heating plate, and a lifting pin provided so as to penetrate the heating plate, which moves up and down to raise and lower the substrate placed on the heating plate. Furthermore, the surface of the heating plate of the substrate processing apparatus has a concave region that slopes downward from the outside to the inside.

[0086] [E2] The substrate processing apparatus according to [E1], wherein the region that protrudes most downward in the concave region is opposite to the central portion of the substrate when the substrate is placed on it.

[0087] [E3] The substrate processing apparatus according to [E1] or [E2], wherein the height of the plurality of gap members from the surface of the provided heating plate to the tip that contacts the substrate is common to each other.

[0088] [E4] The heating plate is a plate-shaped member that receives heat from a heating mechanism and maintains a high temperature through solid heat conduction, and has an area equal to or greater than that of the substrate when viewed from above. The substrate processing apparatus further comprises a plurality of temperature sensors, each provided inside the heating plate so as to correspond to different positions on the substrate, and used to measure the temperature for controlling the heating mechanism. The plurality of temperature sensors are provided so as to be equal in height from their tips to the surface of the heating plate, according to any one of [E1] to [E3].

[0089] [E5] A substrate processing apparatus comprising a base plate that supports the heating plate from below via a support member and has a path hole through which the lifting pin passes, and an upper sealing portion made of a cylindrical insulating material that contacts the lower surface of the heating plate, which is the surface opposite to the surface. The substrate processing apparatus according to any one of [E1] to [E4] further comprising a lower sealing portion that closes the internal space of the path hole in the base plate and the internal space of the upper sealing portion to the space below the base plate.

[0090] [E6] The substrate processing apparatus according to [E5], wherein the lower sealing portion is provided inside the base plate or on the lower surface of the base plate.

[0091] [E7] The substrate processing apparatus according to [E5] or [E6], wherein the upper sealing portion is elastic.

[0092] [E8] A substrate processing apparatus further comprising: a drive unit for raising and lowering the lifting pin; and a control device for controlling the drive unit so that the lifting pin moves up and down. The substrate processing apparatus according to any one of [E1] to [E7], wherein the control device controls the drive unit so that the descent speed of the lifting pin changes during the descent operation of the lifting pin.

[0093] [E9] The substrate processing apparatus according to [E8], wherein the control device controls the drive unit such that the lifting pin descends at a predetermined first speed up to a predetermined first height, and when descending further from the first height, the lifting pin descends at a second speed slower than the first speed.

[0094] [E10] The control device controls the drive unit such that, in the lowering operation, the lifting pin that has reached the first height stops without lowering for a predetermined time, as described in [E9].

[0095] [E11] The control device determines the first height based on the warpage data of the substrate, as described in [E9] or [E10], in the substrate processing apparatus.

[0096] [E12] The substrate processing apparatus according to [E11], further comprising a measuring unit for measuring the amount of warpage data of the substrate.

[0097] [E13] The substrate processing apparatus according to any one of [E1] to [E12], wherein the surface height of the outer edge region of the heating plate is lower than the surface height of the inner region.

[0098] [E14] The substrate processing apparatus according to [E13], wherein the difference in surface height between the outer peripheral region and the inner region is less than 0.2 mm.

[0099] [E15] The substrate processing apparatus according to [E13] or [E14], wherein the gap member has fixing pins provided near the boundary between the outer peripheral region and the inner region to support the substrate.

[0100] [E16] The substrate processing apparatus according to any one of [E13] to [E15], wherein the surface height of the region of the outer edge is constant. [Explanation of Symbols]

[0101] 2...Coating and developing apparatus (substrate processing apparatus), 20, 520...Hot plate, 20a...Surface, 21...Heater (heating mechanism), 22...Gap member, 31...Base plate, 31z...Path hole, 32...Peripheral wall (support member), 140...Control temperature sensor (temperature sensor), 51...Lifting pin, 52...Drive unit, 70...Suction unit, 91...Upper seal unit, 92...Lower seal unit, 100...Control device, 400...Peripheral imaging subunit (measurement unit), 651...Inner region, 652...Peripheral edge region, 722...Fixing pin, V...Gap, W...Wafer.

Claims

1. A heating plate for placing the substrate and heating the placed substrate, A plurality of gap members are formed along the surface on which the substrate is placed on the heating plate, supporting the substrate and ensuring a gap between the heating plate and the substrate, A suction unit that sucks the substrate toward the heating plate, A lifting pin is provided so as to penetrate the aforementioned heating plate, and by moving up and down, it raises and lowers the substrate placed on the heating plate, A drive unit for raising and lowering the aforementioned lifting pin, The system includes a control device that controls the drive unit so that the lifting pin moves up and down, The surface of the heating plate has a concave region that slopes downward from the outside to the inside, The control device controls the drive unit so that the downward speed of the lifting pin changes during the downward movement of the lifting pin. The control device controls the drive unit such that, during the downward movement, the lifting pin descends at a predetermined first speed up to a predetermined first height, and when descending further from the first height, the lifting pin descends at a second speed slower than the first speed. The control device is a substrate processing apparatus that determines the first height based on the warpage data of the substrate.

2. The substrate processing apparatus according to claim 1, wherein the region that protrudes most downward in the concave region faces the central portion of the substrate when the substrate is placed on it.

3. The substrate processing apparatus according to claim 1, wherein the height of the plurality of gap members from the surface of the provided heating plate to the tip that contacts the substrate is common to each other.

4. The aforementioned heating plate is configured to receive heat from a heating mechanism and maintain a high temperature through solid heat conduction, and is a plate-shaped member having an area equal to or greater than that of the substrate when viewed from above. The substrate processing apparatus is The heating plate is further provided with a plurality of temperature sensors, each of which is provided inside the heating plate so as to correspond to a different position on the substrate, and which are used to measure the temperature for controlling the heating mechanism. The substrate processing apparatus according to claim 1, wherein the plurality of temperature sensors are arranged such that their lengths in the height direction from their tips to the surface of the heating plate are equal to each other.

5. A base plate that supports the heating plate from below via a support member and has a path hole through which the lifting pin passes, It is made of a cylindrical insulating material and has an upper sealing portion that contacts the lower surface, which is the surface opposite to the surface of the heating plate, The substrate processing apparatus according to claim 1, further comprising a lower sealing portion that closes the internal space of the path hole in the base plate and the internal space of the upper sealing portion to the space below the base plate.

6. The substrate processing apparatus according to claim 5, wherein the lower sealing portion is provided inside the base plate or on the lower surface of the base plate.

7. The substrate processing apparatus according to claim 5, wherein the upper sealing portion is elastic.

8. The substrate processing apparatus according to claim 1, wherein the control device controls the drive unit so that, in the lowering operation, the lifting pin that has reached the first height stops without lowering for a predetermined time.

9. The substrate processing apparatus according to claim 1, further comprising a measuring unit for measuring the amount of warpage data of the substrate.

10. The substrate processing apparatus according to any one of claims 1 to 9, wherein the surface height of the outer edge region of the heating plate is lower than the surface height of the inner region thereof.

11. The substrate processing apparatus according to claim 10, wherein the difference in surface height between the outer peripheral region and the inner region is less than 0.2 mm.

12. The substrate processing apparatus according to claim 10, wherein the gap member has fixing pins provided near the boundary between the outer peripheral region and the inner region to support the substrate.

13. The substrate processing apparatus according to claim 10, wherein the surface height of the region of the outer edge is constant.

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