Substrate heating device, substrate heating method, and manufacturing method of substrate heating portion

Abstract

The present invention provides a substrate heating device, a substrate heating method, and a manufacturing method of a substrate heating section, which are excellent in temperature control and less likely to cause damage caused by thermal shock. A substrate heating device that heats a substrate in a processing container in which a substrate is processed includes a substrate heating section that has a placement surface on which a substrate is placed and heats the substrate placed on the placement surface using a heater; a sheath section that is provided so as to cover a bottom portion of the substrate heating section with a cooling space interposed; and a cooling gas supply section that supplies a cooling gas to the cooling space.

Description

TECHNICAL FIELD

[0001] The present application relates to a substrate heating apparatus, a substrate heating method, and a manufacturing method of a substrate heating section. BACKGROUND

[0002] In a case where a substrate such as a semiconductor wafer is subjected to a process accompanied by heating, a substrate heating apparatus (heater) that places and heats a substrate is used. For example, a substrate heating apparatus (heater) having an aluminum nitride substrate placement table in which a resistance heating element is embedded and a shaft that engages with the back surface of the substrate placement table is described in Patent Literature 1.

[0003] PRIOR ART DOCUMENTS

[0004] PATENT LITERATURE

[0005] Patent Literature 1: Japanese Patent Application Laid-Open No. 2010-40422 SUMMARY

[0006] PROBLEMS TO BE SOLVED BY THE INVENTION

[0007] The present application provides a substrate heating apparatus, a substrate heating method, and a manufacturing method of a substrate heating section, which are excellent in temperature control and less likely to cause damage caused by thermal shock.

[0008] TECHNICAL SOLUTION FOR SOLVING THE PROBLEMS

[0009] A substrate heating apparatus of one embodiment of the present application is a substrate heating apparatus that heats a substrate in a processing container in which a substrate is processed, and includes a substrate heating section that has a placement surface on which a substrate is placed and heats the substrate placed on the placement surface using a heater; a sheath section that is provided to cover the bottom of the substrate heating section with a cooling space interposed; and a cooling gas supply section that supplies a cooling gas to the cooling space.

[0010] EFFECT OF THE INVENTION

[0011] According to the present application, a substrate heating apparatus, a substrate heating method, and a manufacturing method of a substrate heating section, which are excellent in temperature control and less likely to cause damage caused by thermal shock, are provided. BRIEF DESCRIPTION OF DRAWINGS

[0012] Figure 1 FIG. 1 is a cross-sectional view that shows a substrate heating apparatus of one embodiment.

[0013] Figure 2 FIG. 2 is a cross-sectional view that shows another example of a substrate heating section.

[0014] Figure 3 is a cross-sectional view of the substrate heating apparatus of Figure 1 FIG. 3 along line III-III.

[0015] Figure 4 FIG. 1 is a cross-sectional view for explaining a cooling method in a conventional substrate heating apparatus.

[0016] Figure 5 FIG. 2 is a step cross-sectional view schematically showing one example of a manufacturing method of a substrate heating portion.

[0017] Figure 6 FIG. 3 is a cross-sectional view schematically showing a substrate heating portion obtained by the manufacturing method shown in FIG. 2. Figure 5

[0018] BRIEF DESCRIPTION OF DRAWINGS

[0019] 10: Substrate heating portion

[0020] 11: Placing surface

[0021] 12: Heater

[0022] 13: Base material

[0023] 14: Electrostatic chuck

[0024] 15: Insulator

[0025] 16: Adsorption electrode

[0026] 20: Sheath portion

[0027] 21: Refrigerant flow path

[0028] 22: Shaft

[0029] 30: Cooling gas space

[0030] 31: Cooling gas supply portion

[0031] 53, 54: Sealing ring

[0032] 52: Screw member

[0033] 61, 63, 65: Insulating layer

[0034] 62: Resistive heating element layer

[0035] 64: Electrode layer

[0036] 66: Cover layer

[0037] 100: Substrate heating apparatus

[0038] W: Substrate DETAILED DESCRIPTION

[0039] Hereinafter, embodiments will be described with reference to the drawings.

[0040] Figure 1 ​is a sectional view of a substrate heating device according to one embodiment.

[0041] In the present embodiment, the substrate heating device 100 is used to heat a substrate W, such as a semiconductor wafer, and is provided in a processing vessel used to perform substrate processing, such as film formation processing (CVD, PVD), etching processing, and the like. The substrate heating device 100 of the present embodiment is particularly suitable for cases in which plasma processing is performed as substrate processing.

[0042] The substrate heating device (100) includes a substrate heating portion (10) having a placement surface (11) on which a substrate (W) is placed, which heats the substrate (W) placed on the placement surface (11), and a sheath portion (20) provided so as to cover the bottom of the substrate heating portion (10) with a cooling space (30) interposed therebetween.

[0043] The substrate heating portion 10 is substantially circular-plate shaped, and a heater 12 is embedded in the inside thereof. The heater 12 is configured as an electric resistance heating body, such as one formed of tungsten (W) or molybdenum (Mo), and generates heat by being supplied with electric power from a heater power source 41 via a power supply line. The substrate heating portion 10 has a base material 13 and an electrostatic chuck 14 provided on the base material 13. The base material 13 is stepped in shape with a flange-shaped protruding portion 13a formed in the central portion of the lower surface of the main body portion in a manner that protrudes downward. A plurality of screw member insertion holes are formed in the flange portion 13b in the circumferential direction, and a circular-ring-shaped screw member fixing member 51 is embedded between the main body portion and the flange portion 13b, and the sheath portion 20 can be threadably fixed as described later.

[0044] As the material constituting the base material 13, machinable ceramic can be preferably used. Machinable ceramic has high heat resistance, is suitable for use in heating a substrate W to a temperature of 300°C or higher, and has higher heat shock resistance than aluminum nitride (AIN) and aluminum oxide (AI2O3) that have been used in the past, and is easy to machine. Furthermore, it has relatively high corrosion resistance. As the machinable ceramic, Si-based ceramic, such as SiC, SiO, and a mixture thereof, and BN-based ceramic can be preferably used. As the material constituting the base material 13, graphite, aluminum (Al), and copper (Cu) can also be preferably used. These have high thermal conductivity and high temperature control properties. However, the use of graphite is limited to a non-oxidizing atmosphere, and the use of Al and Cu is limited to use at relatively low temperatures of 200°C or lower. The base material 13 can also be covered with a cover layer made of a material having high corrosion resistance, such as AIN and AI2O3.

[0045] The electrostatic chuck 14 electrostatically holds the substrate W during plasma processing, and has an insulator 15 and a holding electrode 16 embedded in the insulator 15. As the insulator 15, ceramics such as AI2O3, AIN, BN, SiN, etc. is used, and as the holding electrode 16, W, Mo, etc. can be used as well as the heater. Further, as the holding electrode 16, a mesh electrode can be used. By applying a direct current voltage to the holding electrode 16 from a direct current power supply 44 via a power supply line, the substrate W is held by electrostatic attractive force such as Coulomb force via plasma. In the present embodiment, the heater 12 for heating processing is provided at a position below the holding electrode 16 in the insulator 15 of the electrostatic chuck 14.

[0046] The insulator 15, the holding electrode 16, and the heater 12 constituting the electrostatic chuck 14 can be formed of a film formed by a film forming technique such as CVD, ALD, sputtering, for example.

[0047] A thermocouple 42 as a temperature sensor is provided near the placement surface 11 of the electrostatic chuck 14. The signal of the thermocouple 42 is sent to a temperature regulator 43 via a signal line, and a control signal for controlling the temperature is sent from the temperature regulator 43 to the heater power supply 41.

[0048] In the present embodiment, an example is given in which the heater 12 is provided in the electrostatic chuck 14 in the substrate heating section 10, but it can also be formed in the base material 13 as shown in Figure 2 However, in the case where the base material 13 is conductive, it is necessary to cover the heater 12 with an insulator.

[0049] The sheath section 20 is made of metal, and is provided so as to cover substantially the entire bottom of the substrate heating section 10 with the cooling space 30 interposed therebetween, and is threadedly fixed to the central portion of the base material 13 of the substrate heating section 10 by a plurality of threaded members 52. The plurality of threaded members 52 are inserted through threaded member insertion holes provided in the circumferential direction of the flange portion 13b of the protruding portion 13a, and are screwed with the threaded member fixing member 51 as shown in Figure 3 Figure 1

[0050] The sheath section 20 has a shaft 22 provided so as to protrude downward from the central portion when fastened to the substrate heating section 10, and the power supply line and the signal line are inserted through the shaft 22. A flange 22a is formed at the lower end of the shaft 22, and the flange 22a is mounted to the bottom surface of a processing vessel (not shown).

[0051] ​​An annular protrusion 20a, extending upwards, is formed on the outer periphery of the upper surface of the sheath portion 20 to define the cooling space 30. The outer periphery protrusion 20a is hermetically sealed to the outer periphery of the lower surface of the substrate 13 by a sealing ring 53. Furthermore, the shaft 22 of the sheath portion 20 has an upwardly protruding inner periphery protrusion 22b to define the cooling space 30. The inner periphery protrusion 22b is hermetically sealed to the protrusion 13a of the substrate 13 by a sealing ring 54. Since the substrate heating portion 10 is heated to 200°C or higher, the sealing rings 53 and 54 are preferably made of heat-resistant Kalrez (registered trademark) or sealing components with heat resistance equivalent to Kalrez (registered trademark).

[0052] The sheath portion 20 is formed with a stepped shape corresponding to the substrate 13, and the cooling space 30 between the sheath portion 20 and the substrate 13 is also formed with a stepped shape.

[0053] Cooling gas is supplied to the cooling space 30 from the cooling gas supply unit 31. Inert gases such as He, N2, and Ar are used as the cooling gas. The substrate heating unit 10 is cooled by heat exchange using the cooling gas supplied to the cooling space 30. A gas discharge unit (not shown) is provided in the cooling space 30, and the pressure of the cooling space 30 can be controlled by adjusting the gas supply and discharge rates.

[0054] A refrigerant flow path 21 is formed within the sheath portion 20, allowing the flow of liquid refrigerant (e.g., cooling water, CF-based fluids such as Galden). Refrigerant can be circulated from the refrigerant supply portion 23 into the refrigerant flow path 21. By allowing the refrigerant to flow through the refrigerant flow path 21, the substrate heating portion 10 can be cooled more efficiently. However, if the temperature of the substrate heating portion 10 can be controlled simply by supplying cooling gas to the cooling space 30, the refrigerant flow path 21 is unnecessary.

[0055] The heating process performed by the substrate heating device 100 configured as described above will now be explained.

[0056] First, the substrate W is placed into a processing container (not shown) and mounted on the mounting surface 11 of the substrate heating section 10. Substrate processing such as film deposition (CVD, CVD), etching, etc., is performed on the mounted substrate W, typically plasma processing.

[0057] During substrate processing, the substrate W is heated by the heater 12 inside the substrate heating section 10. Then, cooling gas is supplied to the cooling space 30 between the substrate heating section 10 and the sheath section 20 to cool the substrate heating section 10.

[0058] The reason for cooling the substrate heating portion 10 like this is that the temperature of the substrate W sometimes becomes higher than the set temperature due to, for example, heat input from the plasma (heat input due to collision of ions and electrons in the plasma to the substrate W). When the temperature of the substrate W becomes higher than the set temperature, there are cases where a change in film quality such as crystallinity, an increase in processing amount (film thickness or etching amount) due to an increase in reaction speed, causes a situation where the desired processing result cannot be obtained.

[0059] In the past, in the case where the heating temperature of the substrate W is about 2000C, a method of cooling the substrate heating portion by connecting a cooling jacket that makes a coolant such as cooling water flow therethrough to the substrate heating portion has been adopted. On the other hand, in the case where the substrate is heated to a high temperature of 3000C or more, as shown in Patent Document 1, a substrate heating apparatus that uses a ceramic such as AlN as the substrate heating portion on which the substrate is placed, and has a shaft that extends downward in the central portion of the substrate heating portion has been used. Since the heat shock resistance of a ceramic such as AlN is low, when cooling is performed using a cooling jacket in a state where the temperature is 3000C or more, there is a possibility that the substrate heating portion will be damaged due to a temperature difference between a portion that is exposed to the plasma and a portion that is cooled. Therefore, as a way of cooling the substrate heating portion while suppressing damage due to heat shock, as shown in Patent Document 2, it is necessary to adopt a way of providing a cooling jacket 130 that cools the substrate heating portion 110 in which a heater 112 is buried via a shaft 120. However, in this case, heat exchange via the shaft 120 is formed, and it is judged that the temperature control property is insufficient. Figure 4

[0060] In this embodiment, the sheath portion 20 is provided so as to cover substantially the entire bottom portion of the substrate heating portion 10 with the cooling space 30 interposed therebetween, and the cooling gas is made to flow from the cooling gas supply portion 31 to the cooling space 30 to cool the substrate heating portion 10. By this, the cooling gas can be brought into contact with the entire bottom portion of the substrate heating portion 10 to perform heat exchange, and therefore a higher temperature control property can be obtained. Further, since cooling is performed using a gas, the heat shock resistance is low compared to a case where a cooling jacket that makes a coolant flow therethrough is directly connected to the substrate heating portion 10 to perform cooling.

[0061] In this case, the sheath portion 20 is provided with a coolant flow path 21, and the coolant can be made to flow in the coolant flow path 21. By this, the sheath portion 20 itself can be cooled, and the cooling efficiency can be further improved.

[0062] ​Furthermore, the substrate 13 of the substrate heating section 10 is made of free-machining ceramic, thereby achieving high heat resistance, making it suitable for applications where the substrate W is heated to 300°C or higher. Moreover, free-machining ceramic has higher thermal shock resistance than conventionally used AlN or Al2O3, thus further reducing the possibility of damage due to thermal shock, and it is easy to process, thereby reducing manufacturing costs.

[0063] By using materials with high thermal conductivity, such as graphite, Al, and Cu, as the substrate material 13, temperature control can be improved. Among these materials, graphite can also be used at high temperatures, but only in non-oxidizing atmospheres. Al and Cu have poor heat resistance and are suitable for processing at lower temperatures below 200°C.

[0064] Below, refer to Figure 5 An example of a method for manufacturing the substrate heating section 10 will be described. Figure 5 This is a step cross-sectional view schematically illustrating an example of a method for manufacturing the substrate heating section 10.

[0065] First, prepare the substrate 13 obtained by processing the raw materials. Figure 5 (a)). As the substrate 13, free-machining ceramics, graphite, Al, and Cu can be used.

[0066] Next, an insulating layer 61 is formed on the surface of the substrate 13. Figure 5 (b)). As the insulating layer 61, ceramics such as Al2O3, AlN, boron nitride (BN), and silicon nitride (SiN) can be used. These are also corrosion-resistant materials. The insulating layer 61 is formed by film formation techniques such as CVD, ALD, and sputtering. The insulating layer 61 is formed on the entire surface of the substrate 13.

[0067] Next, a resistive heating element layer 62, which becomes the heater 12, is formed on the upper surface of the insulating layer 61 using the same film forming technique as the insulating layer 61. Figure 5 (c)). The resistive heating element layer 62 is formed, for example, by W or Mo.

[0068] Next, an insulating layer 63 is formed on the upper surface of the resistive heating element layer 62 and the entire surface of the exposed insulating layer 61 using the same material as the insulating layer 61 and the same film forming technique. Figure 5 (d)). The portion of insulating layer 63 formed on insulating layer 61 is configured to be an integral insulating layer with insulating layer 61.

[0069] Next, on the upper surface of the insulating layer 63, an electrode layer 64, serving as the adsorption electrode 16, is formed using the same film formation technique as that used for the insulating layer 61. Figure 5 (e)). Electrode layer 64 is formed, for example, by W or Mo.

[0070] Next, an insulating layer 65 is formed on the upper surface of the electrode layer 64 and the entire surface of the exposed insulating layer 63 using the same material as the insulating layer 61 and the same film forming technique. Figure 6 (f)). The portion of insulating layer 65 formed on insulating layer 63 is configured to be an integral insulating layer with insulating layers 61 and 63.

[0071] Through the above steps, a structure is obtained in which a resistive heating element layer 62 and an electrode layer 64 are formed between the insulating layers 61, 63, and 65 formed on the upper surface of the substrate 13, and insulating layers 61, 63, and 65 are also formed on the side and bottom surfaces of the substrate 13. That is, as shown... ​ As shown, the insulating layers 61, 63, and 65 formed on the upper surface of the substrate 13 become the insulator 15 of the electrostatic chuck 14, the resistive heating element layer 62 becomes the heater 12, and the electrode layer 64 becomes the adsorption electrode 16, thus forming the heater 12 and the electrostatic chuck 14. Furthermore, the insulating layers formed on the sides and bottom of the substrate 13 become the covering layer 66 for improving corrosion resistance.

[0072] In this way, by using film forming technology, a coating layer 66 for improving the heater 12, electrostatic chuck 14 and corrosion resistance can be formed simultaneously, which simplifies the process.

[0073] The embodiments have been described above, but it should be considered that the embodiments disclosed herein are illustrative and not restrictive in all respects. The above embodiments can be omitted, substituted, or modified in various ways without departing from the appended claims and their spirit.

[0074] For example, in the above embodiment, the description focuses on the substrate heating device used in the processing container for plasma processing, but it can also be applied to plasma processing, such as that without thermal CVD. Furthermore, in the above embodiment, an example of using an electrostatic chuck to pick up the substrate is given, but it is also possible to use an electrostatic chuck without it.

Claims

1. A substrate heating device that heats a substrate in a processing vessel in which a substrate is processed, the substrate heating device characterized by comprising: a substrate heating portion that has a placement surface on which a substrate is placed, and heats the substrate placed on the placement surface with a heater; a sheath portion that is made of metal, and is provided so as to cover a bottom portion of the substrate heating portion via a cooling space; and a cooling gas supply portion that supplies a cooling gas to the cooling space, wherein an outer peripheral protruding portion that is in a circular ring shape that protrudes upward and that defines the cooling space is formed in an outer peripheral portion of an upper surface of the sheath portion, and the outer peripheral protruding portion and an outer peripheral portion of a lower surface of the substrate heating portion are airtightly sealed by a gasket, wherein a flange-provided protruding portion that protrudes downward is formed in a central portion of a lower surface of the substrate heating portion, a plurality of screw-insertion holes are formed in a circumferential direction in a flange of the protruding portion, a circular ring-shaped screw-fixing member is inserted between the substrate heating portion and the flange, a plurality of screws are inserted into the screw-insertion holes and are screwed with the screw-fixing member, and thereby the sheath portion is fixed to the central portion of the substrate heating portion.

2. The substrate heating device according to claim 1, wherein: the substrate processing in the processing vessel is plasma processing.

3. The substrate heating device according to claim 2, wherein: the substrate heating portion includes: a base material; and an electrostatic chuck that is provided on an upper surface of the base material, has an insulator and an adsorption electrode provided inside the insulator, and electrostatically adsorbs the substrate to the placement surface by applying a direct current voltage to the adsorption electrode.

4. The substrate heating device according to claim 3, wherein: the insulator and the adsorption electrode of the electrostatic chuck are configured as films.

5. The substrate heating device according to claim 3, wherein: the heater is provided inside the insulator of the electrostatic chuck.

6. The substrate heating device according to claim 5, wherein: the heater is configured as a film.

7. The substrate heating device according to any one of claims 3 to 6, wherein: the base material is configured from any one of machinability ceramic, graphite, aluminum, and copper.

8. The substrate heating device according to any one of claims 3 to 6, wherein: the substrate heating portion further has a cover layer that is configured from a corrosion-resistant material and is provided on side surfaces and a bottom surface of the base material.

9. The substrate heating device according to any one of claims 1 to 6, wherein: the sheath portion is threadedly fixed to the central portion of the substrate heating portion by a plurality of screws.

10. The substrate heating device according to any one of claims 1 to 6, wherein: the sheath portion has, inside, a refrigerant flow path through which a liquid-like refrigerant flows.

11. The substrate heating device according to any one of claims 1 to 6, wherein: the sheath portion has a shaft that is provided so as to protrude downward from a central portion, and a lower end of the shaft is attached to a bottom portion of the processing vessel. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 12. A substrate heating method of heating a substrate with a substrate heating device in a processing vessel in which a substrate is processed, the substrate heating method characterized by: the substrate heating device including: a substrate heating section having a placement surface on which a substrate is placed, and heating the substrate placed on the placement surface with a heater; a sheath section made of metal and arranged to cover a bottom portion of the substrate heating section through a cooling space; and a cooling gas supply section that supplies a cooling gas to the cooling space, a circumferential protruding section in the shape of a circular ring protruding upward and defining the cooling space is formed on an outer circumferential portion of an upper surface of the sheath section, and the circumferential protruding section and an outer circumferential portion of a lower surface of the substrate heating section are airtightly sealed by a gasket, a flange-provided protruding section is formed on a lower surface central portion of a main section of the substrate heating section in a manner protruding downward, a plurality of screw-insertion holes are formed in a circumferential direction on a flange of the protruding section, a circular ring-shaped screw-fixing member is inserted between the main section and the flange, a plurality of screws are inserted into the screw-insertion holes and screwed with the screw-fixing member, and thereby the sheath section is fixed to the central portion of the substrate heating section, the substrate heating method including: a step of placing a substrate on the placement surface of the substrate heating section; a step of heating the substrate with the heater of the substrate heating section during substrate processing; and a step of supplying the cooling gas to the cooling space to cool the substrate heating section.

13. The substrate heating method according to claim 12, characterized in that: the substrate processing in the processing vessel is plasma processing.

14. The substrate heating method according to claim 13, characterized in that: the substrate heating device has an electrostatic chuck that electrostatically attracts a substrate on the placement surface, and the substrate is electrostatically attracted when the substrate is placed on the placement surface.

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