KR100861261B1 - Heat transfer structure and substrate processing apparatus - Google Patents

Abstract

Provided is a heat transfer structure capable of maintaining the temperature of a consumable part at 225 ° C or lower during an etching process of a substrate. The substrate processing apparatus 10 includes a chamber 11, and a susceptor 12 having a refrigerant chamber 25 is disposed in the chamber 11, and an upper disc-shaped member on the susceptor 12. The wafer W is mounted thereon, the focus ring 24 is disposed on the lower disc-shaped member so as to surround the wafer W, and the heat conduction is made of a gel material between the electrostatic chuck 22 and the focus ring 24. The sheet 39 is disposed, and the ratio of hardness represented by W / m · K in the thermal conductive sheet 39 is set to less than 20.

Description

Heat transfer structure and substrate processing apparatus {HEAT TRANSFER STRUCTURE AND SUBSTRATE PROCESSING APPARATUS}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to heat transfer structures and substrate processing apparatuses, and more particularly, to heat transfer structures disposed in a reduced pressure processing chamber of a substrate processing apparatus.

Usually, the etching apparatus is widely known as a substrate processing apparatus which processes a board | substrate using a plasma. This substrate processing apparatus is provided with the pressure reduction processing chamber (chamber) which a plasma generate | occur | produces inside, and the mounting table which mounts the wafer as a board | substrate is arrange | positioned in this chamber. The mounting table includes a disk-shaped electrostatic chuck (ESC) disposed above the mounting table, and a focus ring made of silicon, for example, disposed at the outer periphery of the upper surface of the electrostatic chuck.

When etching the wafer, after mounting the wafer on the electrostatic chuck, the inside of the chuck is depressurized and a mixed gas composed of a processing gas such as C ₄ F ₈ gas, O ₂ gas and Ar gas is introduced into the chamber. Then, a high frequency current is supplied into the chamber to generate plasma from the mixed gas. This plasma converges on the wafer by the focus ring and performs etching on the wafer. Although the temperature of a wafer rises by performing an etching process, the said wafer is cooled by the cooling mechanism in which an electrostatic chuck is built. During this cooling, helium (He) gas having excellent heat transfer from the upper surface of the electrostatic chuck flows toward the back surface of the wafer, and the wafer is efficiently cooled by improving the heat transfer between the electrostatic chuck and the wafer.

On the other hand, since the interface between the rear surface of the focus ring and the upper surface of the outer periphery of the electrostatic chuck is an interface in which solids contact each other, the adhesion between the focus ring and the electrostatic chuck is low, and a small gap is generated in the interface. In particular, during the etching process, since the inside of the chamber is depressurized, these gaps form a vacuum heat insulating layer, resulting in low heat transfer between the electrostatic chuck and the focus ring, and the focus ring cannot be efficiently cooled like a wafer. As a result, the temperature of the focus ring becomes higher than the temperature of the wafer.

If the temperature of the focus ring is high, the outer periphery of the wafer becomes higher than the inner part thereof, and the in-plane uniformity of the etching process on the wafer deteriorates.

In addition, during the etching process, a reaction product is generated, which is attached to the side wall of the chamber or the focus ring as a film of a polymer. The attached polymer film protects the focus ring and the like from plasma to prevent the focus ring and the like from being consumed. However, as shown in the graph of FIG. 5, the film thickness of the polymer increases the temperature of the object to be attached (such as the focus ring). It becomes small. Therefore, as described above, when the temperature of the focus ring is high, it is difficult for the polymer of the reaction product to adhere to the focus ring, and since the focus ring is directly exposed to the plasma, the focus ring is consumed quickly.

In addition, since the focus ring is not cooled efficiently by the formed vacuum heat insulating layer part, heat accumulates with time, and the temperature of the focus ring at the time of each wafer process in the etching process of the wafer of the same lot does not become constant. Instead, the form of the etching rate is different in each wafer, for example, in which the process performance deteriorates.

Therefore, the present applicant has proposed a countermeasure for improving the heat transfer property between an electrostatic chuck and a focus ring by making the contact ring and the electrostatic chuck high. Specifically, a heat conductive medium formed of an elastic member having heat resistance such as conductive silicone rubber is interposed between the focus ring and the electrostatic chuck (see Patent Document 1, for example).

In this countermeasure, the heat transfer medium deforms between the focus ring and the electrostatic chuck. Thereby, the adhesiveness of an electrostatic chuck and a focus ring improves, and therefore the heat transfer of an electrostatic chuck and a focus ring improves.

[Patent Document 1] Japanese Unexamined Patent Publication No. 2002-16126

However, in recent years, the level of in-plane uniformity required for etching in wafers has gradually increased, and the life of the focus ring, which is a consumable component, is required to be extended. As a result, the temperature of the focus ring during etching is maintained at 225 ° C or lower. It is required to do it. On the other hand, since the conductive silicone rubber of the heat conductive member has low fluidity, it cannot fill a small gap between the interface between the focus ring and the electrostatic chuck, and as a result, there is a limit to improving the heat transfer performance of the electrostatic chuck and the focus ring by inserting the heat conductive member. In addition, it is difficult to maintain the temperature of the focus ring during the etching process at 225 ° C or lower.

An object of the present invention is to provide a heat transfer structure and a substrate processing apparatus capable of maintaining the temperature of a consumable part during the etching process of a substrate at 225 ° C or lower.

In order to achieve the above object, the heat transfer structure according to claim 1 is a heat transfer structure disposed in a processing chamber in which a substrate is subjected to a plasma treatment under a reduced pressure environment, and has a exposed part exposed to plasma, and the consumed part. Asuka C concerning the thermal conductivity represented by W / m * K in the said heat conductive member provided with the cooling component which cools the heat exchange member, and the heat conductive member arrange | positioned between the said consumable component and the said cooling component, and which consists of a gel material. It is characterized by the ratio of the hardness displayed being less than 20.

The heat transfer structure according to claim 2 is the heat transfer structure according to claim 1, wherein the consumable part is an annular member disposed to surround the outer edge of the substrate, and the cooling part is mounted to mount the substrate and the annular member. It is characterized by a person.

In order to achieve the said objective, the substrate processing apparatus of Claim 3 is a substrate processing apparatus provided with the processing chamber which plasma-processes a board | substrate in a pressure-reduced environment, and the heat-transfer structure arrange | positioned in the said processing chamber, The said heat-transfer structure is a In the heat conductive member, the heat conductive member includes a consumable part having an exposed surface exposed to plasma, a cooling part for cooling the consumable part, and a heat conductive member disposed between the consumable part and the cooling part and made of a gel material. It is characterized by the ratio of the hardness represented by Asuka C with respect to the thermal conductivity represented by W / m * K less than 20.

According to the heat-transfer structure of Claim 1 and the substrate processing apparatus of Claim 3, the heat conductive member which consists of a gel-like material is arrange | positioned between the consumable part which has an exposed surface exposed to plasma, and the cooling component which cools the said consumable part, The ratio of the hardness represented by Asuka C to the thermal conductivity expressed by W / m · K in the thermally conductive member is less than 20. Since the gel-like substance fills a small gap at the interface between the consumable part and the cooling part, and the ratio of the hardness represented by Asuka C with respect to the thermal conductivity expressed in W / m · K in the heat conductive member becomes less than 20, it is consumed. The heat transfer property of components and cooling components can be improved compared with the past. As a result, the temperature of a consumable part can be kept at 225 degrees C or less during the etching process of a board | substrate.

According to the heat transfer structure according to claim 2, since the consumable part is an annular member disposed to surround the outer edge of the substrate, and the cooling part is a mounting table on which the substrate and the annular member are mounted, the annular member is removed during the etching process of the substrate. The temperature can be maintained at 225 ° C or lower, and as a result, the required level of in-plane uniformity of the etching process can be satisfied in the substrate mounted on the mounting table, and the life of the toroidal member can be extended.

EMBODIMENT OF THE INVENTION Hereinafter, embodiment of this invention is described, referring drawings.

First, the substrate processing apparatus provided with the heat exchanger structure which concerns on embodiment of this invention is demonstrated.

1 is a cross-sectional view showing a schematic configuration of a substrate processing apparatus including a heat transfer structure according to the present embodiment. This substrate processing apparatus is comprised so that an etching process may be performed to the polysilicon layer formed on the semiconductor wafer as a board | substrate.

In FIG. 1, the substrate processing apparatus 10 has a chamber 11 (process chamber) for receiving a semiconductor wafer (hereinafter, simply referred to as “wafer”) W having a diameter of 300 mm, for example. In the column), a circumferential susceptor 12 (cooling part) serving as a mounting table on which the wafers W are mounted is disposed. In the substrate processing apparatus 10, the side wall of the chamber 11 and the side surface of the susceptor 12 form a side exhaust passage that functions as a flow path for discharging gas above the susceptor 12 out of the chamber 11. (13) is formed. An exhaust plate 14 is disposed in the middle of the side exhaust passage 13. The inner wall surface of the chamber 11 is covered with quartz or yttrium oxide (Y ₂ O ₃ ).

The exhaust plate 14 is a plate member having a plurality of holes, and functions as a partition plate partitioning the chamber 11 into upper and lower portions. Plasma described later is generated in the upper portion (hereinafter referred to as "reaction chamber") 17 of the chamber 11 partitioned by the exhaust plate 14. In the lower portion of the chamber 11 (hereinafter referred to as an “exhaust chamber (manifold)”) 18, a coarse suction exhaust pipe 15 for exhausting gas in the chamber 11 and the main exhaust pipe 16 are opened. . A DP (Dry Pump) (not shown) is connected to the coarse suction exhaust pipe 15, and a Tmobo (Turbo Molecular Pump) (not shown) is connected to the exhaust pipe 16. In addition, the exhaust plate 14 captures or reflects ions or radicals generated in the processing space S described later in the reaction chamber 17 to prevent leakage to these manifolds 18.

The coarse suction exhaust pipe 15 and the main exhaust pipe 16 discharge the gas of the reaction chamber 17 to the outside of the chamber 11 via the manifold 18. Specifically, the rough suction exhaust pipe 15 depressurizes the inside of the chamber 11 from the atmospheric pressure to the low vacuum state, and the exhaust pipe 16 cooperates with the rough suction exhaust pipe 15 in the low vacuum state. The pressure is reduced to a higher vacuum state (for example, 133 Pa (1 Torr or less)) at a lower pressure.

A lower high frequency power source 19 is connected to the susceptor 12 via a matcher 20, and the lower high frequency power source 19 applies a predetermined high frequency power to the susceptor 12. As a result, the susceptor 12 functions as a lower electrode. In addition, the lower matcher 20 reduces the reflection of the high frequency power from the susceptor 12 to maximize the supply efficiency of the high frequency power to the susceptor 12.

An electrostatic chuck 22 having an electrostatic electrode plate 21 therein is disposed above the susceptor 12. The electrostatic chuck 22 has a shape in which an upper disk member having a smaller diameter than the disk member is superimposed on a lower disk member having a certain diameter. The electrostatic chuck 22 is made of aluminum, and ceramics and the like are sprayed on the upper surface of the upper disk member. When the susceptor 12 mounts the wafer W, the wafer W is disposed on the upper disk member in the electrostatic chuck 22.

In the electrostatic chuck 22, a DC power supply 23 is electrically connected to the electrostatic electrode plate 21. When a positive high DC voltage is applied to the electrostatic electrode plate 21, a negative potential is generated on the surface of the wafer W on the side of the electrostatic chuck 22 (hereinafter referred to as the "back surface"), thereby generating the electrostatic electrode plate 21. ) And a backside of the wafer W, and a potential difference occurs between the backside of the wafer W, and the wafer W is attracted on the upper disc-shaped member in the electrostatic chuck 22 by the Coulomb force or the Johnson Lavec force. maintain.

An annular focus ring 24 (hereinafter referred to as a "focus ring mounting surface") is a portion where the upper disk-shaped member on the upper surface of the lower disk-shaped member of the electrostatic chuck 22 does not overlap. Consumable parts, annular members) are disposed. The focus ring 24 is made of a conductive member, for example silicon, and surrounds the wafer W adsorbed and held on the upper disc-shaped member in the electrostatic chuck 22. In addition, the focus ring 24 has an exposed surface exposed to the processing space S, condenses plasma toward the surface of the wafer W in the processing space S, and improves the efficiency of the etching process.

In the susceptor 12, an annular coolant chamber 25 extending in the circumferential direction, for example, is provided. Low-temperature refrigerant, such as cooling water or galden, is circulated and supplied from the chiller unit (not shown) to the refrigerant chamber 25 via the refrigerant pipe 26. The susceptor 12 cooled by the low temperature coolant cools the wafer W and the focus ring 24 via the electrostatic chuck 22. Therefore, in this embodiment, the susceptor 12 functions as a direct cooling component, and the electrostatic chuck 22 functions as an indirect cooling component. In addition, the temperature of the wafer W and the focus ring 24 is mainly controlled by the temperature and flow rate of the coolant circulated and supplied to the coolant chamber 25.

A plurality of electrothermal gas supply holes 27 are opened in a portion where the wafer W on the upper disk-shaped member in the electrostatic chuck 22 is adsorbed and held (hereinafter, referred to as an "adsorption surface"). The plurality of heat transfer gas supply holes 27 are connected to a heat transfer gas supply unit (not shown) via the heat transfer gas supply line 28, and the heat transfer gas supply unit transfers helium (He) gas as the heat transfer gas. It feeds into the clearance gap between the adsorption surface and the back surface of the wafer W via 27. The helium gas supplied to the gap between the suction surface and the back surface of the wafer W effectively heat transfers the heat of the wafer W to the electrostatic chuck 22.

In the ceiling of the chamber 11, a gas introduction shower head 29 is disposed to face the susceptor 12. The upper high frequency power supply 31 is connected to the gas introduction shower head 29 via the upper matching unit 30, and the upper high frequency power supply 31 applies a predetermined high frequency power to the gas introduction shower head 29. The gas introduction shower head 29 functions as an upper electrode. In addition, the function of the upper matcher 30 is the same as the function of the lower matcher 20 described above.

The gas introduction shower head 29 has a ceiling electrode plate 33 having a plurality of gas holes 32, and an electrode support 34 that detachably supports the ceiling electrode plate 33. A buffer chamber 35 is provided inside the electrode support 34, and a processing gas introduction pipe 36 is connected to the buffer chamber 35. The gas introduction shower head 29 is a process gas supplied from the process gas introduction pipe 36 to the buffer chamber 35, for example, a mixed gas obtained by adding an inert gas such as O ₂ gas and Ar to a cancellation gas or chlorine gas. It is supplied into the reaction chamber 17.

Further, a sidewall of the chamber 11 is provided with an outlet opening 37 used for carrying in and out of the reaction chamber 17 of the wafer W, and the opening and closing opening 37 is opened and closed at the outlet opening 37. The gate valve 38 is attached.

In the reaction chamber 17 of the substrate processing apparatus 10, a high frequency power is applied to the susceptor 12 and the gas introduction shower head 29, and thus, between the susceptor 12 and the gas introduction shower head 29. By applying high frequency power to the processing space S, the processing gas supplied from the gas introduction shower head 20 in the processing space S is a high-density plasma to generate ions and radicals. The wafer W is etched.

On the other hand, the operation of each component of the substrate processing apparatus 10 described above is controlled by a CPU of a controller (not shown) included in the substrate processing apparatus 10 according to a program corresponding to the etching process.

In the substrate processing apparatus 10 described above, in order to effectively conduct heat transfer between the wafer W and the electrostatic chuck 22, a transfer gas is supplied between the wafer W and the electrostatic chuck 22, but the focus ring ( There is no electric heat gas supplied between the 24 and the electrostatic chuck 22. In addition, no heat transfer gas is supplied between the focus ring 24 and the electrostatic chuck 22. In addition, since the focus ring 24 and the electrostatic chuck 22 are each solid, if the focus ring 24 and the electrostatic chuck 22 are in direct contact with each other, the focus ring 24 and the electrostatic chuck 22 are separated from each other. A small gap occurs at the interface. Here, as described above, since the pressure is reduced in the chamber 11 in which the susceptor 12 and the focus ring 24 are arranged, more specifically, in the reaction chamber 17 to a high vacuum state, a minute gap at the interface Forms a vacuum insulation layer.

The wafer W and the focus ring 24 exposed to the plasma rise in temperature due to heat input from the plasma during the etching process, but the wafer W is driven by the susceptor 12 via the electrostatic chuck 22. Since it is cooled, the temperature is maintained at about 100 ° C. On the other hand, when the vacuum heat insulating layer is formed, the focus ring 24 is not cooled by the susceptor 12 via the electrostatic chuck 22, so that the temperature rises to about 450 ° C. That is, the temperature difference between the focus ring 24 and the wafer W increases, but at this time, as described above, the in-plane uniformity of the etching process on the wafer W deteriorates, and the focus ring 24 The consumption is faster. In addition, since heat accumulates in the focus ring 24 with time, process performance in the same lot deteriorates.

In order to solve these problems, what is necessary is just to suppress the temperature of the wafer W in an etching process to 225 degrees C or less, and the focus ring 24 at the time of each wafer process in the etching process of the wafer of the same lot. It is proposed by the present inventors and the like that the difference (deviation) of the highest temperature of the temperature is within ± 30 ° C.

In this embodiment, in consideration of this, the heat transfer property of the focus ring 24 and the electrostatic chuck 22 should be improved, and the occurrence of minute gaps at the interface between the focus ring 24 and the electrostatic chuck 22 is prevented. Suppress Specifically, a heat conductive sheet 39 (heat conductive member) made of a gel material is disposed between the focus ring 24 and the electrostatic chuck 22. Since the thermally conductive sheet 39 made of a gel material has fluidity, the focus ring 24 and the electrostatic chuck 22 are formed by filling the minute gaps to increase the adhesion between the focus ring 24 and the electrostatic chuck 22. To improve the heat transfer. Here, since the heat of the focus ring 24 is transmitted to the susceptor 12 via the heat conductive sheet 39 and the heat of the focus ring 24 through the heat conductive sheet 39 and the electrostatic chuck 22, the focus ring The 24, the heat conductive sheet 39, the electrostatic chuck 22, and the susceptor 12 constitute a heat transfer structure.

Since the thermal conductivity of the thermally conductive sheet 39 is improved as the thermal conductivity of the thermally conductive sheet 39 itself is higher, and the softer the thermally conductive sheet 39 is, that is, the smaller the hardness is, the better the thermal conductivity is. Based on the experiment result by this inventor, the ratio of the hardness represented by Asuka C with respect to the heat transfer rate represented by W / m * K in the heat conductive sheet 39 is set to less than 20. As the heat conductive sheet 39, specifically, "λ GEL" (registered trademark) (Japanese Geltech Co., Ltd.), which is a sheet-shaped heat conductive gel, is used.

Since the heat conductive sheet 39 is an insulating member and the focus ring 24 and the electrostatic chuck 22 are conductive members, the focus ring 24, the heat conductive sheet 39, and the electrostatic chuck 22 constitute a capacitor. If the charge of this capacitor is large, the in-plane uniformity of the etching process is affected in the wafer W, so the capacity of the capacitor needs to be reduced. Therefore, in this embodiment, the thickness of the heat conductive sheet 39 is preferably thinner, and specifically, the maximum value of the thickness of the heat conductive sheet 39 is set to 0.7 mm.

In addition, since the heat conductive sheet 39 has adhesiveness, when the heat conductive sheet 39 is separated from the focus ring 24 and the electrostatic chuck 22 in the exchange of the focus ring 24, the heat conductive sheet 39 is separated. It may be torn and a part thereof may remain in close contact with the focus ring 24 and the electrostatic chuck 22. In particular, part of the thermal conductive sheet 39 in close contact with the electrostatic chuck 22 needs to be removed completely, which may impair the exchange workability of the focus ring 24. Therefore, it is preferable that the thickness of the heat conductive sheet 39 is more than a certain value from a viewpoint of preventing the heat conductive sheet 39 from tearing, and the minimum value of the thickness of the heat conductive sheet 39 is specifically set to 0.3 mm.

According to the thermal conductive sheet 39 as the thermal conductive sheet 39 according to the present embodiment, a gel type is formed between the focus ring 24 and the susceptor 12, more specifically, between the focus ring 24 and the electrostatic chuck 22. A thermally conductive sheet 39 made of a material is disposed, and the ratio of hardness represented by Asuka C to the electrical conductivity expressed by W / m · K in the thermally conductive sheet 39 is set to less than 20. Since the thermally conductive sheet 39 fills a minute gap at the boundary between the focus ring 24 and the electrostatic chuck 22, the thermal conductivity of the focus ring 24 and the susceptor 12 is improved than before, and the susceptor Cooling of the focus ring 24 by (12) can be performed efficiently. As a result, the temperature of the focus ring 24 can be maintained at 225 ° C. or lower during the etching process, thereby preventing the in-plane uniformity of the etching process and the premature consumption of the focus ring 24 in the wafer W. Can be. In addition, it is possible to prevent heat from accumulating in the focus ring 24 with the passage of time, thereby preventing deterioration of the process performance in the same lot.

Further, in the electrostatic chuck 22, the focus ring mounting surface is subjected to polishing, and its surface roughness is set to Ra or lower than 1.6. However, even if a large number of surface roughnesses of the focus ring mounting surface are generated, the thermal conductive sheet 39 can fill these minute gaps sufficiently, so that it is not necessary to necessarily perform flue processing on the focus ring mounting surface. Ra may be 6.3 or more. At this time, the manufacturing cost of the electrostatic chuck 22 can be suppressed by the polishing processing abolishment. In addition, by increasing the surface roughness of the focus ring mounting surface, the actual contact area of the thermal conductive sheet 39 and the electrostatic chuck 22 can be increased, and the thermal conductivity of the focus ring 24 and the electrostatic chuck 22 can be further improved. Can be.

On the other hand, in the present embodiment, the heat conductive sheet 39 is disposed between the electrostatic chuck 22 and the focus ring 24, but the place where the heat conductive sheet 39 is disposed is not limited to this, and is disposed in the chamber 11. What is necessary is just to be between a member to be heated and a member which radiates heat of the member to be heated.

Example

Next, the Example of this invention is described.

First, the present inventor prepared the plurality of heat conductive sheets 39 in which the hardness represented by Asuka C is any one of 10-100, and the thermal conductivity represented by W / m * K is any one of 0.2-17. Then, for each thermal conductive sheet 39, the thermal conductive sheet 39 is disposed between the electrostatic chuck 22 and the focus ring 24 in the substrate processing apparatus 10, and the upper circle in the electrostatic chuck 22. The wafer W is mounted on the plate member to be adsorbed and held, the pressure in the chuck 11 is reduced to a high vacuum state, and helium gas is supplied to the gap between the suction surface and the back surface of the wafer W, and the susceptor ( 12) and the high frequency electric power was applied to the gas introduction shower head 29 at 3 cycles for 3 minutes, and the saturation value (hereinafter referred to as "saturation temperature") of the temperature of the focus ring 24 was measured.

Then, the present inventors put together the saturation temperature, thermal conductivity, and hardness of the measured focus ring 24 in Table 1 below.

Table 1

Thermal Conductivity W / mK Hardness Asuka C conversion value Saturation Temperature ℃ 0.2 10 303 0.8 20 453.1 1.1 15 181.7 1.1 20 162.6 1.2 18 144.7 1.6 29 173.2 2.0 10 130.9 2.0 55 388 2.1 10 104.5 2.3 26 122.4 2.5 27 91.7 3.0 12 81.1 3.0 40 102 3.0 75 106.5 5.0 100 453 6.0 65 89.1 6.0 95 157.3 15.0 20 62.2 17.0 20 55.8

First, the relationship between the thermal conductivity and the saturation temperature is shown graphically in FIG. 2.

According to the graph of FIG. 2, when the saturation temperature is 453.1 ° C. when the thermal conductivity is 0.8 as a whole, when the saturation temperature is 388 ° C. when the thermal conductivity is 2.0 and when it is 453 ° C. when the thermal conductivity is 5.9. There was no clear standard of thermal conductivity for fixing the temperature of the focus ring 24 below the saturation temperature threshold (225 ° C).

The present inventor then shows the relationship between hardness and saturation temperature in the graph of FIG. 3.

According to the graph of FIG. 3, when the hardness is 20, when the saturation temperature is 453.1 ° C., when the hardness is 55, when the saturation temperature is 388 ° C. or when the hardness is 100, the saturation temperature may be 453 ° C. No clear standard of hardness for fixing the temperature of the focus ring 24 below the saturation temperature threshold was obtained.

The present inventors have examined the case where the temperature of the focus ring 24 could not be fixed below the saturation temperature threshold, and in all cases, the case corresponds to a case where the thermal conductivity is large but the hardness is large, or when the hardness is small but the thermal conductivity is small. Found something to do. Thus, the present inventors pay attention to the ratio of hardness with respect to thermal conductivity, obtain the relationship between ratio with respect to thermal conductivity and saturation temperature, and summarize the results in Table 2 below, and show the relationship between the ratio of hardness with respect to thermal conductivity and saturation temperature in FIG. 4. Shown in the graph.

TABLE 2

Hardness / thermal conductivity Saturation Temperature ℃ 50 303 25.0 453.1 13.6 181.7 18.2 162.6 15.0 144.7 18.1 173.2 5.0 130.9 27.5 388 4.8 104.5 11.3 122.4 10.8 91.7 4.0 81.1 13.3 102 25.0 106.5 20.0 453 10.8 89.1 15.8 157.3 1.3 62.2 1.2 55.8

According to the graph of FIG. 4, when the ratio of hardness with respect to thermal conductivity is less than 20, it turned out that the temperature of the focus ring 24 can be fixed below saturation temperature threshold value.

In addition, the inventors of the present invention used each cycle when high frequency power was applied to the susceptor 12 and the gas introduction shower 29 in 3 minutes x 3 cycles using the thermal conductivity sheet 39 having a hardness ratio of less than 20. When the saturation temperature of the focus ring 24 was measured, it was confirmed that the difference of each saturation temperature is ± 30 degrees C or less.

That is, when the ratio of the hardness represented by Asuka C to the thermal conductivity expressed by W / m · K in the thermal conductive sheet 39 is less than 20, the temperature of the focus ring 24 can be fixed below the saturation temperature threshold. It was found that the difference in saturation temperature of the focus ring 24 can be fixed to ± 30 ° C or lower in each high frequency power application cycle.

1 is a cross-sectional view showing a schematic configuration of a substrate processing apparatus having a heat transfer structure according to an embodiment of the present invention;

FIG. 2 is a graph showing the relationship between the thermal conductivity of the thermal conductive sheet and the saturation temperature of the focus ring in FIG. 1;

3 is a graph showing the relationship between the hardness of the thermal conductive sheet and the saturation temperature of the focus ring in FIG.

4 is a graph showing the relationship between the ratio of hardness to the thermal conductivity of the thermal conductive sheet and the saturation temperature of the focus ring in FIG. 1;

5 is a graph showing a relationship between a film thickness of a polymer to be attached and a temperature of an object to be attached.

<Description of the symbols for the main parts of the drawings>

10 substrate processing apparatus 11 chamber

12: susceptor 22: electrostatic chuck

24: focus ring 25: refrigerant chamber

39: heat conductive sheet S: processing space

W: Wafer

Claims (3)

In the heat transfer structure arranged in the processing chamber which performs a plasma process to a board | substrate in a pressure reduction environment, A consumable part having an exposed surface exposed to the plasma, A cooling part for cooling the consumable part; A heat conducting member disposed between the consumable part and the cooling part and made of a gel material; The ratio of the hardness represented by Asuka C with respect to the thermal conductivity displayed by W / m * K in the said heat conductive member is less than 20, It is characterized by the above-mentioned. Heat transfer structure. The method of claim 1, The consumable part is an annular member disposed to surround the outer edge of the substrate, and the cooling part is a mounting table on which the substrate and the annular member are mounted. Heat transfer structure. In the substrate processing apparatus provided with the processing chamber which performs a plasma processing to a board | substrate in a pressure reduction environment, and the heat-transfer structure arrange | positioned in the said processing chamber, The heat conductive structure has a consumable part having an exposed surface exposed to the plasma, a cooling part for cooling the consumable part, and a heat conducting member disposed between the consumable part and the cooling part and further comprising a gel material, The ratio of the hardness represented by Asuka C with respect to the thermal conductivity represented by W / m * K in the said heat conductive member is less than 20, It is characterized by the above-mentioned. Substrate processing apparatus.

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