Electrostatic chuck, substrate processing apparatus and substrate processing method

Abstract

To be able to sufficiently fix a substrate without bringing other parts into contact with the top surface of the substrate when processing the substrate under high temperatures, for example, and to accurately control the temperature to the substrate.SOLUTION: An electrostatic chuck for electrostatically adsorbing a substrate, comprises a first base material on which the substrate is located on the upper surface; and a second base material located on the lower surface of the first base material, the first base material comprises a plate member made of a composite material of metal and ceramics, and an insulating layer formed in layer form on the top surface of the plate member and having insulating properties, and the second base material is composed of a material with a thermal expansion coefficient close to that of the composite material.SELECTED DRAWING: Figure 1

Description

[Technical field]

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

[0002] In a manufacturing process of a semiconductor device, a film is formed on a semiconductor wafer (hereinafter referred to as a "wafer"), which is a substrate, by chemical vapor deposition (CVD) or atomic layer deposition (ALD). This film formation process is performed by supplying a film formation gas to a wafer placed on a stage in a processing chamber while the wafer is heated to a predetermined temperature by a heater provided on the stage. There is also known a film formation apparatus that fixes the wafer to the stage by pressing the edge of the wafer on the stage with a ring-shaped fixing member when performing the film formation process (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 5699425 Summary of the Invention [Problem to be solved by the invention]

[0004] The technology disclosed herein enables a substrate to be securely fixed without contacting the top surface of the substrate with other components, for example, when processing the substrate at high temperatures, and also enables accurate temperature control of the substrate. [Means for solving the problem]

[0005] One aspect of the technology disclosed herein is an electrostatic chuck that electrostatically attracts a substrate, the electrostatic chuck comprising: a first substrate on an upper surface of which the substrate is placed; and a second substrate disposed on a lower surface of the first substrate, the first substrate comprising a plate-shaped member made of a composite material of metal and ceramics, and an insulating layer formed in a layered manner on the upper surface of the plate-shaped member and having insulating properties; and the second substrate is made of a material having a thermal expansion coefficient close to that of the composite material. Effect of the Invention

[0006] According to the present disclosure, for example, when processing a substrate at high temperatures, the substrate can be sufficiently fixed without contacting the top surface of the substrate with other members, and the temperature of the substrate can be accurately controlled. [Brief description of the drawings]

[0007] [Figure 1] 1 is a schematic cross-sectional view of a substrate processing apparatus (electrostatic chuck) according to a first embodiment of the technique disclosed herein. [Diagram 2] FIG. 2 is a schematic enlarged cross-sectional view of an area [A] surrounded by a two-dot chain line in FIG. [Diagram 3] FIG. 11 is a schematic enlarged cross-sectional view of an electrostatic chuck in a second embodiment of the technique disclosed herein. [Figure 4] FIG. 11 is a diagram showing an example of a simulation result of a gas flow. [Diagram 5] 11 is a schematic cross-sectional view of a substrate processing apparatus (electrostatic chuck) according to a third embodiment of the technique disclosed herein. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] As described above, in the technology of Patent Document 1, when a film formation process is performed, the edge of the wafer on the mounting table is pressed and fixed to the mounting table with a ring-shaped fixing member. However, it is desirable to make the contact area between the wafer and the fixing member as small as possible during the film formation process, and in recent years, it has been desired to fix the wafer to the mounting table without pressing it down with a fixing member.

[0009] In addition, in the technology of Patent Document 1, only the edge of the wafer is pressed down to the stage by a fixing member, and the other part is simply placed on the stage by the weight of the wafer. Therefore, the wafer and the stage may be separated from each other more than expected, which may make it difficult to control the temperature of the wafer by the heater provided on the stage.

[0010] Hereinafter, an embodiment of the technology according to the present disclosure will be described with reference to the drawings. However, the configurations described in the following embodiments are merely examples, and the present invention is not limited to these configurations. For example, each part included in this configuration can be replaced with any other part that can perform the same function. In addition, any other components may be added.

[0011] First Embodiment A first embodiment will be described below with reference to Fig. 1 and Fig. 2. Fig. 1 is a schematic cross-sectional view of a substrate processing apparatus (electrostatic chuck) according to a first embodiment of the technique disclosed herein. Fig. 2 is a schematic enlarged cross-sectional view of an area [A] surrounded by a two-dot chain line in Fig. 1. Note that in Figs. 1 and 2 (as well as Figs. 3 to 5), the vertical direction (thickness direction, height direction) of the substrate processing apparatus is exaggerated compared to the horizontal direction in order to facilitate understanding, and the ratio between the vertical length and the horizontal length is different from the actual ratio.

[0012] The substrate processing apparatus 100 shown in FIG. 1 is an apparatus that performs a film formation process (substrate processing method) on a semiconductor wafer W (hereinafter referred to as "wafer W"), which is a substrate, in a manufacturing process of a semiconductor device. The film formation process is not particularly limited, and for example, a film formation process by CVD or the like is possible. Then, by this CVD, a ruthenium (Ru) film, which is a metal film, is formed on the surface of the wafer W. The substrate processing apparatus 100 includes an electrostatic chuck 10 and a processing chamber 20 that houses the electrostatic chuck 10. The electrostatic chuck 10 is an apparatus that electrostatically attracts the wafer W. The processing chamber 20 is an apparatus that performs a film formation process on the wafer W in a state in which the wafer W is electrostatically attracted to the electrostatic chuck 10. The inside of the processing chamber 20 is adjusted to a vacuum atmosphere of a desired pressure by a pressure adjustment unit (not shown), and ruthenium is supplied as a processing gas (film formation gas) G1 by a ruthenium supply unit (not shown). Then, by performing temperature control on the wafer W in this state, a ruthenium film can be formed on the surface of the wafer W. In addition, the processing chamber 20 is grounded.

[0013] 1, the electrostatic chuck 10 is a laminate including a first substrate 1 having a disk shape (plate shape) on the upper surface of which a wafer W is placed, and a second substrate 2 having a disk shape (plate shape) and disposed concentrically with the first substrate 1 on the lower surface side of the first substrate 1. The electrostatic chuck 10 is supported on a support table 40. In the substrate processing apparatus 100, the electrostatic chuck 10 and the support table 40 form a mounting table 50 on which the wafer W is placed.

[0014] The first base material 1 includes a plate-shaped member 11 and an insulating layer 12 formed in layers on the upper surface of the plate-shaped member 11. The plate-shaped member 11 is made of a composite material (MMC: Metal Matrix Composites) of metal and ceramics. The composite material is not particularly limited, and for example, a composite material of aluminum and silicon carbide can be used. The insulating layer 12 is made of an insulating material having insulating properties. The insulating material is not particularly limited, and for example, aluminum oxide (alumina) can be used. An electrode 13 is provided inside the insulating layer 12, that is, in the middle of the insulating layer 12 in the thickness direction. The electrode 13 is connected to a DC power source 15 via a conductive wire 14. This applies a voltage to the electrode 13. The negative pole side of the DC power source 15 is preferably earthed. A switch 16 is provided in the middle of the conductive wire 14. The electrostatic chuck 10 is a Johnson-Rahbek type electrostatic chuck, and can adsorb the wafer W by the Johnson-Rahbek force. Specifically, by turning on the switch 16, the wafer W and the electrode 32 function as opposing electrodes of a capacitor and are polarized across the entire surfaces of both sides via the insulating layer 12. This allows the entire surface of the wafer W to be attracted to the electrostatic chuck 10. The method for forming the insulating layer 12 is not particularly limited, and examples of the method include a method in which, with the electrode 13 disposed on the upper surface of the plate-like member 11, aluminum oxide, which is a material constituting the insulating layer 12, is thermally sprayed onto the upper surface.

[0015] The second substrate 2 is made of a metal material having a thermal expansion coefficient (thermal expansion coefficient) close to that of the composite material constituting the plate-like member 11 of the first substrate 1. This metal material is not particularly limited, and may be any of titanium, aluminum oxide, an alloy of copper and tungsten, an alloy of copper and molybdenum, and chromium, with titanium being preferred. The thermal expansion coefficient of the composite material constituting the plate-like member 11, for example, when the composite material is made of aluminum and silicon carbide, is about 3×10, depending on the respective contents, i.e., the compounding ratio. -6 ~14×10 -6[ / ℃]. On the other hand, the thermal expansion coefficient of titanium is 8.4×10 -6 ~8.6×10 -6 [ / ℃]. In this embodiment, "the thermal expansion coefficients of the composite material constituting the plate-like member 11 and the metal material constituting the second base material 2 are close to each other" means that "there is a portion where the thermal expansion coefficient of the composite material and the thermal expansion coefficient of the metal material overlap", but is not limited thereto. Titanium is also preferable as a constituent material of the second base material 2 because it is relatively easy to obtain. The thickness t2 of the second base material 2 is thicker than the thickness t11 of the plate-like member 11 of the first base material 1. The thickness t11 is preferably, for example, 5 mm or more and 20 mm or less, and more preferably 12 mm or more and 15 mm or less. In this case, the thickness t2 is preferably 1.5 times or more and 20 times or less, and more preferably 5 times or more and 10 times or less, of the thickness t11. In addition, the number of second base materials 2 arranged is one in the configuration shown in FIG. 1, but is not limited thereto, and may be, for example, a plurality.

[0016] The first substrate 1 and the second substrate 2 are bonded together via a bonding material 8. The bonding material 8 may be made of any material, such as aluminum. When the bonding material 8 is made of aluminum, the first substrate 1 and the second substrate 2 are heated while an aluminum sheet material is placed between them as the bonding material 8. The first substrate 1 and the second substrate 2 are pressed together in a direction in which they approach each other. This causes the aluminum constituting the bonding material 8 to melt, and the first substrate 1 and the second substrate 2 are bonded together. This allows the heat from the heating unit 9 provided on the second substrate 2 to be transferred to the wafer W through the first substrate 1 without excess or deficiency when a film formation process is performed on the wafer W. In this embodiment, the first substrate 1 and the second substrate 2 are bonded together via the bonding material 8. However, the bonding material is not limited to this, and the first substrate 1 and the second substrate 2 may be bonded together by a method using screws or a method using a clamp member.

[0017] The second base material 2 is provided with a heating section 9 for heating the wafer W. The heating section 9 is composed of a plurality of heaters 91 embedded in the second base material 2. Each heater 91 generates heat when electricity is applied. The heaters 91 are arranged in a horizontally distributed manner. The heat generated by each heater 91 is transferred to the wafer W electrostatically attracted onto the first base material 1 through the second base material 2 and the first base material 1 in this order. The temperature of the electrostatic chuck 10 (each heater 91) depends on the film formation process, but is preferably 150° C. or higher and 250° C. or lower, and more preferably 150° C. or higher and 160° C. or lower. In this embodiment, each heater 91 is embedded in the second base material 2, but may be embedded in the plate-like member 11 of the first base material 1. However, processing for embedding each heater 91 is easier when processing the second base material 2 made of a metal material than when processing the plate-like member 11 made of a composite material. For this reason, it is preferable to embed each heater 91 in the second base material 2.

[0018] By using the electrostatic chuck 10 having the above-mentioned configuration, when a film formation process is performed on the wafer W at a high temperature, the film formation process can be performed while the wafer W is in close contact with the electrostatic chuck 10 by electrostatic adsorption. This makes it possible to omit other members such as an annular clamp ring that is disposed on the upper side of a conventional electrostatic chuck and presses and fixes the wafer W. Therefore, the electrostatic chuck 10 can sufficiently fix the wafer W without causing the other members to come into contact with the upper surface of the wafer W. This allows the film formation process on the wafer W to be stably performed. Note that, when performing a film formation process, it may be desired to avoid the other members from coming into contact with the upper surface of the wafer W. Therefore, electrostatic adsorption by the electrostatic chuck 10 is preferable for the film formation process.

[0019] As described above, the inside of the processing chamber 20 is adjusted to a vacuum atmosphere of a desired pressure, and ruthenium, which is the processing gas G1, is supplied. Then, by controlling the temperature of the wafer W in this state, a ruthenium film can be formed on the surface of the wafer W. Since ruthenium is relatively sensitive to temperature changes, it is preferable to control the temperature of the entire wafer W as accurately as possible during film formation. Therefore, the electrostatic chuck 10 is configured to include a plate-shaped member 11 (first base material 1) made of a composite material. As a result, when the heat from each heater 91 is transferred to the plate-shaped member 11, it is transferred to the wafer W via the insulating layer 12 in a state in which the heat is uniformly diffused to the wafer W by the plate-shaped member 11. In this way, the plate-shaped member 11 has a thermal diffusion function for diffusing heat. As a result, it is possible to control the temperature of the entire wafer W as accurately as possible during film formation, and therefore it is possible to form a ruthenium film uniformly. In this case, the variation in the surface temperature of the wafer W during film formation is usually suppressed to a range of ±1°C. Here, let us consider a case in which the plate-shaped member 11 is omitted. In this case, the insulating layer 12 is provided on the second base material 2. The heat from each heater 91 is not dispersed as uniformly in the second base material 2 as in the plate-like member 11, and is instead transferred to the wafer W via the insulating layer 12. With such transfer, it becomes difficult to accurately control the temperature of the entire wafer W during film formation, and as a result, the ruthenium film may be formed non-uniformly.

[0020] In the electrostatic chuck 10, the first substrate 1 and the second substrate 2 are both thermally deformed by the heat from the heaters 91, but since they have similar thermal expansion coefficients, they tend to undergo similar thermal deformation. This makes it possible to prevent or suppress warping of the electrostatic chuck 10 and maintain the bonded state between the first substrate 1 and the second substrate 2, thereby enabling stable heating of the wafer W on the electrostatic chuck 10. The thermal expansion coefficient of aluminum oxide is 7.0×10 -6 ~7.7×10 -6[ / °C]. When the insulating layer 12 is made of aluminum oxide, the insulating layer 12 has a thermal expansion coefficient close to that of the plate-shaped member 11. This allows the insulating layer 12 to maintain the state of being formed on the plate-shaped member 11 even when heated by the heat from each heater 91, that is, it is possible to prevent the insulating layer 12 from peeling off from the plate-shaped member 11 or cracking.

[0021] As shown in FIG. 2, the electrostatic chuck 10 includes a gas discharge unit (gas discharge system) 5 that discharges a film formation suppression gas (gas) G2 that suppresses film formation on a desired portion. In this embodiment, the film formation suppression target is an edge portion W1 of the wafer W and an edge portion 511 of a first flow control unit 51 of the gas discharge unit 5, which will be described later. The film formation suppression gas G2 is not particularly limited, and for example, carbon monoxide (CO) gas can be used. The gas discharge unit 5 is connected to a gas supply source (not shown) that supplies the film formation suppression gas G2. The gas discharge unit 5 has a first flow control unit (flow control unit) 51 provided on the upper surface of the second substrate 2 and a second flow control unit 52 provided on the side surface of the second substrate 2. The first flow control unit 51 is a flat annular member that is arranged concentrically with the second substrate 2. The second flow control unit 52 is an annular member that is along the circumferential direction of the side surface of the second substrate 2. The first flow control unit 51 and the second flow control unit 52 are components that control the flow of the film formation inhibiting gas G2. Note that the constituent materials of the first flow control unit 51 and the second flow control unit 52 are not particularly limited, and for example, the same constituent material as the second base material 2 can be used.

[0022] The gas discharge unit 5 has a flow path 53 through which the film formation suppression gas G2 passes. The flow path 53 is composed of a flow path 531, a flow path 532, a flow path 533, a flow path 534, a flow path 535, and a flow path 536. The flow path 531 is a flow path formed between the second base material 2 and the support stand 40. The flow path 532 is a flow path that is connected to the flow path 531 and is formed by penetrating the second base material 2 in the vertical direction (thickness direction). The flow path 533 is a flow path that is connected to the flow path 532 and is formed between the first flow control unit 51 and the first base material 1. The flow path 534 is a flow path that is connected to the flow path 531 and is formed between the second flow control unit 52 and the second base material 2. The flow path 535 is a flow path that is connected to the flow path 534 and is formed by penetrating the protruding portion 521 of the second flow control unit 52 that protrudes toward the second base material 2 side in the vertical direction (thickness direction). The flow path 536 is in communication with the flow path 535 and is formed between the first flow control portion 51 and the second flow control portion 52 .

[0023] The flow path 532 has a first outlet (exhaust port) 532a that opens on the upper surface of the second base material 2. The first outlet 532a discharges the film formation inhibiting gas G2 to the edge portion W1 of the wafer W on the first base material 1 through the flow path 533. This allows the film formation inhibiting gas G2 to contact the edge portion W1 of the wafer W preferentially over the processing gas G1, and therefore prevents or inhibits the processing gas G1 from contacting the edge portion W1. As a result, the formation of a ruthenium film on the edge portion W1 can be inhibited. Note that the lower surface (back surface) of the wafer W is in close contact with the electrostatic chuck 10, so that the formation of a ruthenium film is inhibited. In addition, the flow path 533 can control the flow of the film formation inhibiting gas G2 discharged from the first outlet 532a. Specifically, the flow path 533 has a relaxation portion 533a on its upstream side that relaxes the flow rate of the film formation inhibiting gas G2 and directs the film formation inhibiting gas G2 in a direction away from the wafer W. The relaxation section 533a is configured by a groove formed in an annular shape on the lower surface of the first flow control section 51. The depth of the relaxation section 533a (groove) is constant. By providing this relaxation section 533a, the film formation inhibiting gas G2 discharged from the first discharge port 532a is sprayed uniformly over as wide an area as possible against the edge W1 of the wafer W. This improves the film formation effect of the film formation inhibiting gas G2 on the edge W1.

[0024] The flow path 536 also has a second outlet 536a for discharging the film formation inhibiting gas G2 to the edge 511 of the first flow control section 51. This allows the film formation inhibiting gas G2 to come into contact with the edge 511 of the first flow control section 51 in preference to the processing gas G1, and therefore prevents or inhibits the processing gas G1 from coming into contact with the edge 511. As a result, the formation of a ruthenium film on the edge 511 can be inhibited. The film formation inhibiting gas G2 from the second outlet 536a can also inhibit the formation of a ruthenium film on the side surface of the second flow control section 52. The second flow control section 52 is configured to be detachable from the second substrate 2, for example, by screwing. This allows the second flow control section 52 to be removed and cleaned to remove the ruthenium film, even if a ruthenium film is formed on the side surface of the second flow control section 52. The second flow control section 52 can also be replaced with a new one.

[0025] As shown in FIG. 2, the gas discharge unit 5 has a ring member 54 concentrically disposed between the protruding portion 521 of the second flow control unit 52 and the second base material 2. The ring member 54 is made of an elastic material such as various rubber materials and various thermoplastic elastomers, and is disposed in a compressed state between the second flow control unit 52 and the second base material 2. In addition, in this embodiment, the temperature of the support table 40 is controlled to, for example, 80° C. at which film formation can be suppressed. The second flow control unit 52 is configured to be detachable from the support table 40 by, for example, screwing. The temperature of the second flow control unit 52 is also controlled to 80° C. like the temperature of the support table 40. In contrast, the temperature of the electrostatic chuck 10 is controlled to, for example, 155° C. The ring member 54, together with the flow path 531 and the flow path 534, can prevent the heat of the electrostatic chuck 10 from being taken away by the second flow control unit 52 and the support table 40. This allows the temperature of the electrostatic chuck 10 to be stably maintained at 155° C. In this manner, the ring member 54, together with the flow passages 531 and 534, serves as a member that exhibits a heat insulating function.

[0026] Although not shown, the electrostatic chuck 10 is provided with a coolant flow path through which a coolant passes, a thermocouple for detecting the temperature of the electrostatic chuck 10, and the like. Although not shown, the electrostatic chuck 10 is provided with a plurality of lift pins that are supported so as to be capable of appearing in and disappearing from the electrostatic chuck 10, i.e., capable of being raised and lowered. When the wafer W is carried into the processing chamber 20, the wafer W can be supported on the lift pins that are protruding from the surface of the electrostatic chuck 10. Then, each lift pin is lowered while supporting the wafer W, enabling a film formation process on the wafer W on the electrostatic chuck 10. When the wafer W after the film formation process is carried out of the processing chamber 20, each lift pin is again protruded from the surface of the electrostatic chuck 10, and the wafer W is supported on each lift pin. Then, the wafer W can be carried out in this state.

[0027] <Second embodiment> Hereinafter, the second embodiment will be described with reference to Figs. 3 and 4, focusing on the differences from the above-mentioned embodiment, and the description of the similar matters will be omitted. This embodiment is similar to the first embodiment except for the difference in the configuration (shape) of the flow path of the gas exhaust part. Fig. 3 is a schematic enlarged cross-sectional view of an electrostatic chuck in the second embodiment of the technology according to the present disclosure. Fig. 3(b) is an enlarged drawing of the area [B] surrounded by the two-dot chain line in Fig. 3(a). Fig. 4 is a diagram showing an example of a simulation result of the gas flow.

[0028] As shown in FIG. 3(a), in this embodiment, the gas discharge unit 5 has a flow path 55 through which the film formation suppression gas G2 passes. This flow path 55 is composed of a flow path 551, a flow path 552, a flow path 553, a flow path 554, and a flow path 555. The flow path 551 is a flow path formed between the second base material 2 and the support stand 40, and has a function similar to that of the flow path 531 of the flow path 53 in the first embodiment. The flow path 552 is a flow path formed between the second flow control unit 52 and the second base material 2, which communicates with the flow path 551, and has a function similar to that of the flow path 534 of the flow path 53 in the first embodiment. The flow path 553 is a flow path formed between the first flow control unit 51 and the second base material 2, which communicates with the flow path 552. The flow path 554 is a flow path formed between the first flow control unit 51 and the first base material 1, which communicates with the flow path 553, and has a function similar to that of the flow path 533 of the flow path 53 in the first embodiment. The flow path 555 is connected to the flow path 552, and is formed between the first flow control portion 51 and the second flow control portion 52, and has a function similar to that of the flow path 536 of the flow path 53 in the first embodiment.

[0029] As shown in FIG. 3(b), the flow path 554 has a relaxation section 554a on the downstream side thereof, which relaxes the flow rate of the film formation suppression gas G2 and directs the film formation suppression gas G2 in a direction away from the wafer W. The relaxation section 554a is configured as a groove formed in an annular shape on the upper surface of the first flow control section 51. The depth of the relaxation section 554a (groove) changes in two stages (stepwise), and the depth DP1 of the deepest part is preferably 1.5 mm or more and 3.0 mm or less, and more preferably 1.5 mm or more and 2.0 mm or less. The depth DP2 of the shallowest part is preferably 0.8 mm or more and 1.5 mm or less, and more preferably 0.8 mm or more and 1.2 mm or less. In addition, a gap is formed between the shallowest part and the wafer W, and the size GP of the gap is preferably 0.2 mm or more and 0.5 mm or less, and more preferably 0.2 mm or more and 0.3 mm or less. The width WD1 of the deepest portion is preferably 1 mm or more and 2 mm or less, and more preferably 1 mm or more and 1.5 mm or less. The distance WD2 from the sidewall of the relaxation portion 554a to the edge W1 of the wafer W is preferably 0.5 mm or more and 5 mm or less, and more preferably 1 mm or more and 3 mm or less. The bottom of the deepest portion is rounded, and the radius R is preferably 0.2 mm or more and 0.5 mm or less, and more preferably 0.4 mm or more and 0.5 mm or less.

[0030] The diagram showing the simulation results shown in Fig. 4 is a diagram showing an example of the simulation results of the gas flow in the relaxation section 554a and its periphery. This gas contains the process gas G1 and the film formation suppression gas G2. As shown in Fig. 4, it can be seen that the gas flows in a direction away from the wafer W around the upper side of the wafer W. This confirms that the effect of the relaxation section 554a is exerted, and film formation on the edge portion W1 of the wafer W is prevented.

[0031] <Third embodiment> Hereinafter, the third embodiment will be described with reference to Fig. 5, focusing on differences from the above-mentioned embodiments, and description of similar matters will be omitted. This embodiment is similar to the first embodiment except for the layered structure of the electrostatic chuck. Fig. 5 is a schematic cross-sectional view of a substrate processing apparatus (electrostatic chuck) according to the third embodiment of the technology disclosed herein.

[0032] As shown in FIG. 5, in this embodiment, the electrostatic chuck 10 includes a first substrate 1 and a second substrate 2, and further includes a third substrate 3 and a fourth substrate 4 formed into a laminate. The third substrate 3 is plate-shaped and disposed on the lower surface side of the second substrate 2. The third substrate 3 is made of the same composite material as the plate-shaped member 11. The fourth substrate 4 is plate-shaped and disposed on the lower surface side of the third substrate 3. The fourth substrate 4 is made of the same metal material as the second substrate 2, that is, a metal material having a thermal expansion coefficient close to that of the composite material constituting the plate-shaped member 11. In addition, the second substrate 2 and the third substrate 3 and the third substrate 3 and the fourth substrate 4 can be bonded with an aluminum bonding material, as in the case of the first substrate 1 and the second substrate 2. With such a laminated structure, even if the first substrate 1 to the fourth substrate 4 are thermally deformed, the difference in thermal expansion between the substrates is alleviated, and thus it is possible to prevent or suppress the occurrence of warping in the electrostatic chuck 10. This allows stable heating of the wafer W on the electrostatic chuck 10. In the configuration shown in Fig. 5, the thickness t11 of the plate-like member 11 is equal to the thickness t3 of the third substrate 3, and the thickness t2 of the second substrate 2 is equal to the thickness t4 of the fourth substrate 4, but the relationship in thickness between the substrates is not limited thereto.

[0033] Although the preferred embodiments of the present disclosure have been described above, the present disclosure is not limited to the above-described embodiments, and various modifications and changes are possible within the scope of the gist of the present disclosure. [Explanation of symbols]

[0034] 1 First base material 11 Plate-shaped member 12 Insulating layer 2 Second base material 10 Electrostatic Chuck 20 Processing Room 100 Substrate processing apparatus W wafer

Claims

1. An electrostatic chuck for electrostatically adsorbing a substrate, The first substrate on which the aforementioned substrate is placed on the upper surface, The invention comprises a second substrate disposed on the lower side of the first substrate, The first substrate comprises a plate-shaped member made of a composite material of metal and ceramics, and an insulating layer formed in layers on the upper surface of the plate-shaped member and having insulating properties. An electrostatic chuck wherein the second substrate is made of a material with a coefficient of thermal expansion similar to that of the composite material.

2. The electrostatic chuck according to claim 1, wherein the composite material is a composite material of aluminum and silicon carbide.

3. The electrostatic chuck according to claim 1, wherein the second substrate is made of titanium, an alloy of copper and tungsten, an alloy of copper and molybdenum, and chromium.

4. The electrostatic chuck according to claim 1, wherein the first substrate and the second substrate are joined together via a bonding material.

5. The electrostatic chuck according to claim 4, wherein the bonding material is made of aluminum.

6. The electrostatic chuck according to claim 1, wherein the insulating layer is made of aluminum oxide.

7. The electrostatic chuck according to claim 1, wherein an electrode is provided inside the insulating layer to which a voltage is applied when the substrate is electrostatically attracted.

8. The electrostatic chuck according to claim 1, further comprising a gas discharge unit having a discharge port for discharging gas from the edge of the substrate on the first substrate.

9. The aforementioned discharge port is provided opening to the upper surface of the second substrate, The electrostatic chuck according to claim 8, wherein the gas discharge section is provided on the upper surface of the second substrate and has a flow control section that controls the flow of the gas discharged from the discharge port.

10. The flow control unit forms a flow path between itself and the first substrate through which the gas passes. The electrostatic chuck according to claim 9, wherein the flow path has a mitigation section on its upstream or downstream side that reduces the flow velocity of the gas and directs the gas away from the substrate.

11. The electrostatic chuck according to claim 9, wherein the gas discharge section has a second discharge port for discharging the gas toward the edge of the flow control section, when the discharge port is designated as the first discharge port.

12. A third substrate is disposed on the lower side of the second substrate, The invention comprises a fourth substrate disposed on the lower side of the third substrate, The third substrate is composed of the composite material, The electrostatic chuck according to claim 1, wherein the fourth substrate is made of a material with a coefficient of thermal expansion similar to that of the composite material.

13. The electrostatic chuck according to claim 1, further comprising a heating section provided on the second substrate for heating the substrate.

14. The electrostatic chuck according to claim 1, used when depositing a ruthenium film on the aforementioned substrate.

15. A substrate processing apparatus comprising: an electrostatic chuck for electrostatically adsorbing a substrate; and a processing chamber in which the electrostatic chuck is housed, and in which a film deposition process is performed on the substrate while the substrate is electrostatically adsorbed to the electrostatic chuck, The electrostatic chuck is, The first substrate on which the aforementioned substrate is placed on the upper surface, The invention comprises a second substrate disposed on the lower side of the first substrate, The first substrate comprises a plate-shaped member made of a composite material of metal and ceramics, and an insulating layer formed in layers on the upper surface of the plate-shaped member and having insulating properties. The substrate processing apparatus wherein the second substrate is made of a material with a coefficient of thermal expansion similar to that of the composite material.

16. A substrate processing method for applying a film deposition treatment to a substrate, When the aforementioned film deposition process is performed on the substrate, the substrate is electrostatically attracted to the electrostatic chuck. The electrostatic chuck is, The first substrate on which the aforementioned substrate is placed on the upper surface, The invention comprises a second substrate disposed on the lower side of the first substrate, The first substrate comprises a plate-shaped member made of a composite material of metal and ceramics, and an insulating layer formed in layers on the upper surface of the plate-shaped member and having insulating properties. A substrate processing method wherein the second substrate is made of a material with a coefficient of thermal expansion similar to that of the composite material.

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