Substrate support table and plasma processing apparatus

Abstract

The present invention provides a substrate support table and a plasma processing apparatus. A technique is provided for controlling the temperature of a substrate placed on the substrate support table with good responsiveness. In one exemplary embodiment, a substrate support table is provided. The substrate support table includes a first member, a second member, a substrate support portion, and one or more thermoelectric elements. The first member has a concave portion in the upper part and is made of metal. The second member is provided on the first member for sealing the concave portion and is made of metal. The substrate support portion is provided on the second member. The thermoelectric elements are arranged in the concave portion. The concave portion is filled with a heat transfer medium.

Description

Technical Field

[0001] Exemplary embodiments of the present disclosure relate to a substrate support table and a plasma processing apparatus. Background Art

[0002] Patent Document 1 discloses a technology related to a mounting table capable of performing temperature adjustment within a wide temperature range. The mounting table has a hollow ceramic housing formed by sintering, a heating element or a heat exchange element (Peltier element), a cooling plate built in the housing, and a mounting portion. The heating element or the heat exchange element is built in the housing, and the housing provides a mounting table capable of performing temperature adjustment within a wide temperature range. The mounting portion is formed on the housing, and a substrate is mounted on the mounting surface. The heating element or the heat exchange element is compression-bonded to the cooling plate.

[0003] Patent Document 2 discloses a technology related to a temperature-controlled semiconductor substrate holder. The substrate holder has a plurality of thermoelectric modules, a temperature sensor, a power supply interface, and a controller. The thermoelectric modules are in heat transfer contact with a substrate holder surface including an electrode biased by radio frequency. The temperature sensor acquires temperature information of the central portion and the end region of the substrate. The power supply interface is connected to the plurality of thermoelectric modules to control the temperature of the substrate holder surface in the central portion and the end region of the substrate. The controller controls the current supplied to the plurality of thermoelectric modules in the central portion and the end region of the substrate with respect to the substrate based on the temperature information acquired by the temperature sensor.

[0004] Patent Document 1: Japanese Unexamined Patent Application Publication No. 2016-082077

[0005] Patent Document 2: Japanese Patent Application Laid-Open No. 2000-508119 Summary of the Invention

[0006] Problems to be Solved by the Invention

[0007] The present disclosure provides a technology for controlling the temperature of a substrate mounted on a substrate support table with good responsiveness.

[0008] Solutions for Solving the Problems

[0009] In one exemplary embodiment, a substrate support table is provided. The substrate support table includes a first member, a second member, a substrate support portion, and one or more thermoelectric elements. The first member has a concave portion in the upper part and is made of metal. The second member is provided on the first member to seal the concave portion and is made of metal. The substrate support portion is provided on the second member. The thermoelectric elements are arranged in the concave portion. The concave portion is filled with a heat transfer medium.

[0010] Effects of the Invention

[0011] By adopting the present disclosure, it is possible to control the temperature of a substrate placed on a substrate support table with good responsiveness. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 FIG. is an example showing the main structure of a plasma processing apparatus according to an exemplary embodiment.

[0013] Figure 2 FIG. is an example showing the main structure of a substrate support table according to an exemplary embodiment.

[0014] Figure 3 FIG. is a diagram showing another example of the main structure of a substrate support table according to an exemplary embodiment.

[0015] Figure 4 is a partial representation of Figure 2 the structure of the support portion shown.

[0016] Figure 5 FIG. is a diagram for explaining the arrangement of one or more thermoelectric elements SP1a.

[0017] Figure 6 FIG. is a flowchart showing a method according to an exemplary embodiment. DETAILED DESCRIPTION

[0018] Hereinafter, various exemplary embodiments will be described. In one exemplary embodiment, a substrate support table is provided. The substrate support table includes a first member, a second member, a substrate support portion, and one or more thermoelectric elements. The first member has a concave portion at an upper portion and is made of metal. The second member is provided on the first member to seal the concave portion and is made of metal. The substrate support portion is provided on the second member. The thermoelectric elements are disposed in the concave portion. The concave portion is filled with a heat transfer medium.

[0019] In one exemplary embodiment, one or more thermoelectric elements are dispersedly arranged along the substrate support portion. One or more thermoelectric elements are arranged at uniform intervals in the circumferential direction of the substrate support portion.

[0020] In one exemplary embodiment, one or more thermoelectric elements are densely arranged at a position on the substrate support portion closer to the peripheral side than its center.

[0021] In one exemplary embodiment, the first member further includes a flow path through which a temperature control medium flows. The flow path is connected to a first chiller and a second chiller in such a way that the first chiller and the second chiller can be switched. The temperature control medium supplied from the first chiller and the temperature control medium supplied from the second chiller are different in temperature from each other.

[0022] In one exemplary embodiment, the substrate support portion further includes a heater electrode.

[0023] In an exemplary embodiment, a heater electrode is provided between a substrate support portion and one or more thermoelectric elements.

[0024] In an exemplary embodiment, the heat transfer medium is a liquid.

[0025] In an exemplary embodiment, the heat transfer medium is an inert gas.

[0026] In an exemplary embodiment, the first member includes one or more storage regions. The one or more storage regions are arranged along the substrate support portion. Each of the one or more thermoelectric elements is stored together with the heat transfer medium in each of the one or more storage regions.

[0027] In an exemplary embodiment, the second member is provided between the substrate support portion and one or more recesses. The one or more recesses are sealed by the second member.

[0028] In an exemplary embodiment, the thermoelectric element is fixed to the first member in the recess using a heat-conductive adhesive.

[0029] In an exemplary embodiment, one or more thermoelectric elements are electrically connected in series in the circumferential direction of the substrate support portion.

[0030] In an exemplary embodiment, a plasma processing apparatus is provided. The plasma processing apparatus includes any one of the above-described substrate support tables.

[0031] Hereinafter, various exemplary embodiments will be described in detail with reference to the drawings. In the respective drawings, the same or corresponding parts are denoted by the same reference numerals.

[0032] Mainly with reference to Figure 1 and Figure 2 the structure of the plasma processing apparatus 1 according to an exemplary embodiment will be described. Figure 1 The illustrated plasma processing apparatus 1 is a capacitively coupled plasma processing apparatus. In addition, Figure 1 the substrate support table WP according to an illustrated embodiment is not limited to a capacitively coupled plasma apparatus, and can also be applied to various plasma processing apparatuses such as an inductively coupled type.

[0033] The plasma processing apparatus 1 has a chamber 10. The chamber 10 has, for example, a cylindrical shape. The surface of the chamber 10 can be made of, for example, aluminum subjected to anodizing treatment (anodic oxidation treatment). The chamber 10 is grounded.

[0034] Inside the chamber 10, there is a substrate support table WP. The substrate support table WP is arranged at the bottom of the chamber 10. The substrate support table WP has a housing BD. The housing BD is, for example, a sintered hollow cylindrical member. The material of the housing BD is, for example, ceramic. The substrate support table WP includes a substrate support portion WS, a metal support portion SP, a heater EP2, and one or more thermoelectric elements SP1a. The thermoelectric element SP1a includes a plurality of elements formed by connecting P-type thermoelectric materials and N-type thermoelectric materials in series. This thermoelectric element SP1a is an element capable of controlling the substrate support portion side to a high temperature or, conversely, to a low temperature by controlling the magnitude and direction of the direct current applied to the element. The thermoelectric element has the property that when either the upper surface or the lower surface becomes a high temperature (heat dissipation), the other becomes a low temperature (heat absorption). The response of the thermoelectric element is good.

[0035] The substrate support portion WS is configured to support a semiconductor wafer (hereinafter referred to as "substrate W"). The substrate support portion WS is provided on the support portion SP. Figures 1 to 4 An example where the substrate support portion WS is an electrostatic chuck is shown. An edge ring ER can be arranged above the substrate support table WP so as to surround the substrate support portion WS.

[0036] The electrostatic chuck includes a dielectric SB and an adsorption electrode EP1 located within the dielectric SB.

[0037] A DC power supply 12a is connected to the adsorption electrode EP1. Under the action of the electrostatic force generated by applying a voltage from the DC power supply 12a to the adsorption electrode EP1, the substrate W is adsorbed.

[0038] The heater EP2 is provided between the adsorption electrode EP1 and one or more thermoelectric elements SP1a. In one example, the heater EP2 can also be provided within the dielectric SB. In other examples, the heater EP2 can also be provided between the substrate support portion WS and the support portion SP. In still other examples, the heater EP2 can also be buried in the support portion SP.

[0039] A heater power supply 12c is connected to the heater EP2. The heater EP2 is configured to generate heat using the direct current applied from the heater power supply 12c.

[0040] The support part SP has a first member SP1 and has a second member SP2 on the first member SP1. The first member SP1 and the second member SP2 are formed of a metal having good heat conductivity, such as aluminum. Since the second member SP2 is made of metal, good heat uniformity within the surface of the substrate W can be achieved. The first member SP1 and the second member SP2 can not only be under the substrate support part WS, but also extend under the edge ring ER. The substrate support part WS is provided on the second member SP2. The substrate support part WS can be joined to the upper surface of the second member SP2 (the surface of the second member SP2 on the side opposite to the first member SP1 side) using an adhesive. In other examples, the substrate support part WS can also be fixed to the second member SP2 by a mechanical means such as a clamp.

[0041] The first member SP1 includes one or more receiving areas SP1b. In addition, one or more recesses CP are formed in the upper part of the first member SP1. In this embodiment, a case where the recesses CP are formed integrally with the first member SP1 in the upper part of the first member SP1 is shown, but the recesses can also be formed by other members and the first member SP1. The second member SP2 is provided between the one or more receiving areas SP1b and the substrate support part WS. The one or more receiving areas SP1b are respectively delimited and formed by the respective recesses of the one or more recesses CP and the second member SP2, and are hermetically sealed. The recesses CP are sealed by the second member SP2, and the receiving areas SP1b are airtight or liquidtight. A heat transfer medium SP1c and each of the one or more thermoelectric elements SP1a are respectively received in the one or more receiving areas SP1b. In one example, the one or more receiving areas SP1b can also be arranged along the substrate support part WS.

[0042] In one embodiment, each of the one or more thermoelectric elements SP1a is respectively arranged in each of the one or more recesses C, the recesses CP are filled with the heat transfer medium SP1c, and are sealed by the second member SP2. In other modes, as Figure 3 shown, an area for arranging the thermoelectric elements SP1a is delimited and formed in the common recess CP, and the thermoelectric elements SP1a are arranged in the respective delimited areas. The recesses CP are filled with the heat transfer medium SP1c, and are sealed by the second member SP2. Moreover, in any mode, the interval between the thermoelectric element SP1a and the second member SP2 is set to be sufficiently narrow, or the thermoelectric element SP1a can also be in contact with the second member SP2 so that the heat conduction between the thermoelectric element SP1a and the second member SP2 is good. In addition, Figure 3The first component SP1 shown has a first region SP11 and a second region SP12. The first region SP11 is provided on the second region SP12. One or more recesses CP are provided in the first region SP11, and a flow path SP1d is provided in the second region SP12. The first region SP11 and the second region SP12 may also be joined by a heat-conductive adhesive.

[0043] The heat transfer medium SP1c can be a heat-conductive liquid or an inert gas. Examples of the heat transfer medium SP1c include pure water or He gas. Preferably, the heat transfer medium SP1c has low electrical conductivity. In one example, the thermoelectric element SP1a is fixed inside the first component SP1 using a heat-conductive adhesive. The adhesive may contain fillers. In other examples, the thermoelectric element SP1a may be disposed on the support portion SP (the inner surface of the recess CP) without using an adhesive.

[0044] As Figure 4 shown, the main body SP1e of the second component SP2 and the first component SP1 are fixed by fixing members BR such as screws and sealing materials such as O-rings RG. The fixing member BR has good heat transfer and electrical conductivity.

[0045] In addition, in other examples, the second component SP2 and the main body SP1e may also be joined using a heat-conductive adhesive with good heat transfer performance.

[0046] One or more thermoelectric elements SP1a are each connected to a DC power supply 12b. The thermoelectric element SP1a cools or heats according to the direction of the current applied from the DC power supply 12b.

[0047] As Figure 5 shown, one or more thermoelectric elements SP1a are electrically connected in series on the circumferential direction DR of the substrate support portion WS. More specifically, one or more thermoelectric elements SP1a are connected in series on each circumferential direction DR of the substrate support portion WS. Therefore, the current supplied to the thermoelectric element SP1a can be controlled on each circumferential direction DR. Moreover, a broken wire can also be detected.

[0048] One or more thermoelectric elements SP1a are dispersedly arranged along the substrate support portion WS. As Figure 5 shown, one or more thermoelectric elements SP1a are arranged at uniform intervals on the circumferential direction DR of the substrate support portion WS.

[0049] One or more thermoelectric elements SP1a may be arranged densely (at a high density) at positions on the substrate support portion WS closer to the peripheral side than its central portion CE. Figure 5 The first region EA1 and the second region EA2 shown are an example of the regions where the thermoelectric elements SP1a are arranged. The thermoelectric elements SP1a may also be arranged outside the first region EA1 and the second region EA2.

[0050] The first region EA1 is a region that extends along the circumference CR under the circumference CR of the substrate support portion WS. The second region EA2 is located under the central portion CE of the substrate support portion WS and is a region that covers the central portion CE.

[0051] One or more thermoelectric elements SP1a are arranged to be denser (higher density) in the first region EA1 than in the second region EA2.

[0052] The above-mentioned density (higher density) can be, for example, that the ratio of the length occupied by one or more thermoelectric elements SP1a arranged on a circumference (such as the circumference CR) extending in the circumferential direction DR to the length of the circumference is relatively high.

[0053] In addition, consider the first ratio of the area occupied by one or more thermoelectric elements SP1a arranged in the first region EA1 to the area of the first region EA1 and the second ratio of the area occupied by one or more thermoelectric elements SP1a arranged in the second region EA2 to the area of the second region EA2. In this case, the density (higher density) can be, for example, that the first ratio is greater than the second ratio.

[0054] In addition, the thermoelectric element SP1a can be arranged not only under the substrate support portion WS but also under the edge ring ER.

[0055] The first member SP1 includes a flow path SP1d through which a temperature control medium (heat carrier and refrigerant) flows. The flow path SP1d is connected to the first refrigerator 107a and the second refrigerator 107b in such a way that the first refrigerator 107a and the second refrigerator 107b can be switched.

[0056] The temperature control medium supplied from the first refrigerator 107a and the temperature control medium supplied from the second refrigerator 107b are different in temperature from each other. For example, in the present embodiment, the temperature control medium supplied from the first refrigerator 107a is a heat carrier, and the temperature control medium supplied from the second refrigerator 107b is a refrigerant. In this case, the temperature control medium (heat carrier) supplied from the first refrigerator 107a is temperature-controlled to, for example, 80°C, and the temperature control medium (refrigerant) supplied from the second refrigerator 107b is controlled to, for example, -30°C.

[0057] The temperature control medium (heat carrier and refrigerant) circulates in the flow path SP1d in the support portion SP from the inlet 105a of the flow path SP1d and flows out from the outlet 105b of the flow path SP1d and then returns to the first refrigerator 107a and the second refrigerator 107b again.

[0058] The above-described substrate support table WP can adjust the temperature of the substrate W placed on the substrate support portion WS within a wide temperature range by controlling the direction of the current supplied to one or more thermoelectric elements SP1a, the temperature of the temperature control medium flowing through the support portion SP, and the temperature of the heater EP2.

[0059] In addition, a first high-frequency power supply 32 for exciting plasma is connected to the substrate support table WP via a first matcher 33. A second high-frequency power supply 34 for introducing ions in the plasma into the substrate W is connected to the substrate support table WP via a second matcher 35. The first high-frequency power supply 32 can be connected to a nozzle 31 described later.

[0060] The nozzle 31 is provided as an upper electrode at the ground potential on the top of the chamber 10 via a dielectric 40. Thus, high-frequency power from the first high-frequency power supply 32 can be capacitively applied between the substrate support table WP and the nozzle 31.

[0061] The nozzle 31 includes an electrode plate 56 having a plurality of gas vent holes 55 and an electrode support 58 that supports the electrode plate 56 so as to be detachable. The gas supply source 15 is configured to supply gas into the nozzle 31 via a gas supply pipe 45. The gas is introduced into the chamber 10 from the plurality of gas vent holes 55 through diffusion chambers 50a and 50b respectively arranged in two gas supply paths.

[0062] An exhaust pipe 60 forming an exhaust port is provided at the bottom of the chamber 10. The exhaust pipe 60 is connected to an exhaust device 65. The exhaust device 65 has a vacuum pump such as a turbo molecular pump or a dry pump, and is configured to reduce the pressure of the processing space in the chamber 10 to a preset vacuum degree and exhaust the gas in the chamber 10 from the exhaust port of the exhaust pipe 60 to the outside of the chamber 10.

[0063] A heat transfer gas such as helium (He) supplied from a heat transfer gas supply source 85 can be supplied to the back surface of the substrate W via a gas pipe 130. Thus, heat transfer between the back surface of the substrate W and the support portion SP is promoted.

[0064] The inside of the chamber 10 is decompressed to a desired vacuum degree by the exhaust device 65.

[0065] A preset gas is introduced into the chamber 10 in a spray shape from the nozzle 31. High-frequency power is applied to the substrate support table WP from the first high-frequency power supply 32 and the second high-frequency power supply 34. Plasma is generated from the introduced gas using the high-frequency power, and the substrate W is etched.

[0066] The control unit Cnt includes a CPU, a ROM, a RAM, etc., and controls the operations of various parts of the plasma processing apparatus 1 as a whole by executing a computer program stored in the ROM or the like. In particular, the control unit Cnt executes Figure 6 the method MT shown

[0067] According to the structure described above, the thermoelectric element SP1a is thermally coupled to the metal support portion SP via the heat transfer medium SP1c, and the support portion SP is in contact with the substrate support portion WS. The support portion SP and the heat transfer medium SP1c are excellent in heat transfer properties and have good thermal responsiveness. Therefore, the heat absorption effect and the heating effect of the thermoelectric element SP1a favorably affect the substrate support portion WS. The temperature of the substrate W placed on the substrate support portion WS can be controlled with good responsiveness.

[0068] By combining the cooling (heat absorption) and heating (heat dissipation) by the thermoelectric element SP1a, the cooling and heating by the temperature control medium flowing in the flow path SP1d, and the heating by the heater EP2, the temperature of the substrate support table WP can be adjusted within a wide range. By flowing a temperature control medium (refrigerant) into the flow path SP1d and causing the thermoelectric element SP1a to perform a heat absorption operation, the temperature of the substrate W can be adjusted to a lower temperature. By flowing a temperature control medium (heat carrier) into the flow path SP1d and causing the heater EP2 to heat, the temperature of the substrate W can be adjusted to a higher temperature.

[0069] Referring to Figure 6 , a method MT according to an exemplary embodiment of the temperature control method will be described. The method MT includes a step ST1 and a step ST2. The method MT, for example, etches a multilayer film on the substrate W.

[0070] In the step ST1, the control unit Cnt places the substrate W on the substrate support table WP. In the step ST2 following the step ST1, the control unit Cnt controls the current supplied to one or more thermoelectric elements SP1a disposed inside the first member SP1 by the DC power supply 12b.

[0071] In process ST2, the control unit Cnt adjusts the temperature of the substrate support table according to the type of film to be etched. Specifically, it controls the current value supplied to one or more thermoelectric elements SP1a, the current value supplied to the heater EP2, and the cooler. Here, the control of the current value supplied to one or more thermoelectric elements SP1a includes not only controlling the magnitude of the current but also controlling the direction of the current. In addition, the control of the temperature of the cooler includes not only adjusting the temperature of the heat medium but also may include switching between the first cooler 107a and the second cooler 107b.

[0072] The following is an example for illustration: The substrate support part WS is set to the first temperature to etch the first film in the multilayer film. After the etching of the first film, the substrate support part WS is set to the second temperature lower than the first temperature to etch the underlying second film. The control unit Cnt controls the heater power supply 12c to heat the heater EP2. Moreover, it controls the first cooler 107a to circulate the heat carrier on the substrate support table. Thereby, the substrate W is heated to etch the first film. At this time, the DC power supply 12b can be controlled to energize the thermoelectric element SP1a, so that the part of the thermoelectric element SP1a on the side of the substrate support part WS becomes high temperature. After the first film is etched, the second film is etched. The control unit Cnt controls the DC power supply 12b to make the part of the thermoelectric element SP1a on the side of the substrate support part WS become low temperature (heat absorption). Moreover, it switches to the second cooler 107b to circulate the refrigerant on the substrate support table. Thereby, the substrate W is cooled to etch the second film. It is also possible to control the current supplied to the heater EP2 during the etching of the second film for temperature adjustment. Since the thermoelectric element SP1a, the first cooler 107a, the second cooler 107b, and the heater EP2 are used, temperature adjustment can be performed with good responsiveness within a large temperature range.

[0073] The above has described various exemplary embodiments, but is not limited to the above embodiments, and various omissions, substitutions, and changes can also be made. In addition, elements in different exemplary embodiments can be combined to form other exemplary embodiments.

[0074] Based on the above description, various exemplary embodiments of the present disclosure have been described in this specification for illustrative purposes. It should be understood that various changes can be made without departing from the scope and gist of the present disclosure. Therefore, the various exemplary embodiments disclosed in this specification are not intended to be limiting, and the true scope and gist are shown by the claims.

Claims

1. A substrate support table, wherein, the substrate support table includes: a first member having a recess at an upper portion thereof and made of metal; a second member provided on the first member for sealing the recess and made of metal; a substrate support portion provided on the second member; a flow path provided below the recess and through which a temperature control medium flows; and one or more thermoelectric elements disposed in the recess, wherein an edge ring is disposed so as to surround the substrate support portion; the substrate support portion includes an electrostatic chuck having a dielectric and an adsorption electrode located within the dielectric; the one or more thermoelectric elements include thermoelectric elements disposed below the edge ring and overlapping the edge ring and the flow path in the vertical direction when viewed from the horizontal direction; the recess is filled with a heat transfer medium which is a liquid.

2. The substrate support table according to claim 1, wherein, one or more of the thermoelectric elements are dispersedly disposed along the substrate support portion, one or more of the thermoelectric elements are disposed at uniform intervals in the circumferential direction of the substrate support portion.

3. The substrate support table according to claim 1 or 2, wherein, one or more of the thermoelectric elements are densely disposed at positions on the substrate support portion closer to the periphery than the center thereof.

4. The substrate support table according to claim 1 or 2, wherein, the flow path is provided in the first member, the flow path is connected to a first chiller and a second chiller in such a manner that the first chiller and the second chiller can be switched, the temperature control medium supplied from the first chiller and the temperature control medium supplied from the second chiller are different from each other in temperature.

5. The substrate support table according to claim 1 or 2, wherein, the substrate support table further includes a heater electrode.

6. The substrate support table according to claim 5, wherein, the heater electrode is provided between the substrate support portion and one or more of the thermoelectric elements.

7. The substrate support table according to claim 1 or 2, wherein, the first member includes one or more storage regions, one or more of the storage regions are disposed along the substrate support portion, one or more of the thermoelectric elements are respectively stored together with the heat transfer medium in respective ones of the one or more storage regions.

8. The substrate support table according to claim 7, wherein, the second member is provided between the substrate support portion and one or more of the storage regions, one or more of the storage regions are defined by the recess and the second member.

9. The substrate support table according to claim 1 or 2, wherein, the thermoelectric elements are fixed to the first member in the recess using a heat-conductive adhesive.

10. The substrate support table according to claim 1 or 2, wherein, one or more of the thermoelectric elements are electrically connected in series in the circumferential direction of the substrate support portion.

11. A plasma processing apparatus, wherein, the plasma processing apparatus includes the substrate support table according to any one of claims 1 to 10.

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