KR101432375B1 - Substrate loading system, substrate treatment apparatus, electrostatic chuck and substrate cooling method - Google Patents

Abstract

Provided is a substrate loading system that has a sufficient cooling effect even for a substrate having a large volume resistivity value such as a large glass substrate and can obtain a cooling effect of a substrate that is cost-effective. In the substrate cooling system of the substrate processing apparatus 10, the susceptor 12 carries the substrate G, and the electrostatic chuck 14 is provided on the susceptor 12 to electrostatically adsorb the substrate G The gas flow path 18 and the temperature regulating gas supply device 19 supply the temperature regulating gas to the heat transfer space T between the electrostatically attracted substrate G and the electrostatic chuck 14, And the gas flow path 18 and the temperature regulating gas supply device 19 supply nitrogen gas or oxygen gas as the temperature regulating gas to the heat transfer space T at 3 Torr (400 Pa) or less.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a substrate loading system, a substrate processing apparatus, an electrostatic chuck, and a substrate cooling method,

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a substrate stacking system, substrate processing apparatus, electrostatic chuck and substrate cooling method for cooling relatively large substrates mounted on a substrate stacking table.

A predetermined process such as a plasma process is performed on a substrate for FPD in the process of manufacturing a relatively large flat panel display (FPD) including a liquid crystal display (LCD), for example, a FPD after the seventh generation Is known.

This substrate processing apparatus has a substrate stacking table for stacking substrates in a processing chamber (hereinafter referred to as a " chamber "), and an upper electrode arranged so as to face the substrate stacking table and spaced apart from the processing space. The substrate mounting table is supplied with a high frequency power (RF) for plasma generation, the substrate loading table functions as a lower electrode, and a plasma is generated by the high frequency power from the processing gas introduced into the processing space in the chamber. The generated plasma is subjected to a predetermined plasma treatment with respect to the substrate to be mounted on the substrate mounting table. An electrostatic chuck is provided on an upper part of the substrate stacking table. While the substrate is subjected to a predetermined plasma treatment, the electrostatic chuck attracts the substrate by applying an electrostatic attraction force to the substrate.

The substrate subjected to the predetermined plasma treatment is subjected to heat reception due to the collision of cations in the plasma or the like and the temperature rises. Therefore, a temperature adjustment gas is caused to flow between the substrate and the substrate mounting table, The temperature of the substrate is maintained at a predetermined temperature by feeding heat to the substrate.

Such a temperature control gas is called a back cooling gas (hereinafter simply referred to as "BC gas") of a substrate, but helium (He) gas, which is an inert gas and has a high thermal conductivity, is generally used as the BC gas , See Patent Document 1).

Japanese Patent Application Laid-Open No. 2006-245563

However, since the substrate for FPD is made of glass and has a large volume resistivity value, the electrostatic attraction force acting on the substrate becomes the Coulomb force rather than the Johnson-backed force. Normally, since the Coulomb force is weaker than the Johnson-Bebeck force, the substrate can not be strongly attracted toward the substrate mounting table (electrostatic chuck), and the pressure of the He gas between the substrate and the substrate mounting table can not be increased. Therefore, in the substrate processing apparatus for performing the plasma processing on the substrate for FPD, the pressure of the He gas between the substrate and the substrate mounting table is set to about 3 Torr (400 Pa) or less.

When the pressure of the He gas is set to about 3 Torr or less, the flow state of the He gas shifts from the viscous flow region to the molecular flow region, and the heat flux of the He gas is greatly lowered. Further, since the He gas is generally expensive, if a He gas is used as the temperature adjustment gas in a substrate processing apparatus for performing plasma processing on a substrate for FPD, a cooling effect of the substrate that is costly can not be obtained.

SUMMARY OF THE INVENTION An object of the present invention is to provide a substrate mounting system, a substrate processing apparatus, an electrostatic chuck, an electrostatic chuck, and an electrostatic chuck, which have a sufficient cooling effect even for a substrate having a large volume resistivity value, And a substrate cooling method.

In order to achieve the above object, a substrate cooling system according to claim 1 includes a substrate mounting table for mounting a substrate thereon, an electrostatic chuck for mounting the substrate on the surface of the substrate mounting table on which the substrate is mounted, And a gas supply system for supplying a temperature adjustment gas to the electro-thermal chuck between the electrostatically chucked substrate and the electrostatic chuck, wherein a thickness of the heat transfer space is set to 50 μm or less, And nitrogen gas or oxygen gas as the temperature regulation gas is supplied to the heat transfer space at 3 Torr or less.

The substrate cooling system according to claim 2 is characterized in that, in the substrate cooling system according to claim 1, the thickness of the heat transfer space is set to 10 μm or less.

The substrate cooling system according to claim 3 is characterized in that, in the substrate cooling system according to claim 1 or 2, a plurality of convex portions are provided on a suction surface of the substrate in the electrostatic chuck.

In the substrate cooling system according to claim 4, in the substrate cooling system according to claim 1 or 2, the attraction surface of the substrate in the electrostatic chuck is formed to be smooth.

In order to achieve the above object, a substrate processing apparatus according to a fifth aspect of the present invention includes: a receiving chamber for receiving a substrate; and a substrate stacking table disposed in the accommodating chamber for stacking the substrate, And a gas supply system for supplying a temperature adjusting gas to the heat transfer space between the electrostatically chucked substrate and the electrostatic chuck, the substrate processing apparatus comprising: Wherein the thickness of the heat transfer space is set to 50 mu m or less and the gas supply system supplies nitrogen gas or oxygen gas as the temperature regulation gas to the heat transfer space at 3 Torr or less.

The substrate processing apparatus according to claim 6 is characterized in that, in the substrate processing apparatus according to claim 5, the thickness of the heat transfer space is set to 10 μm or less.

According to a seventh aspect of the present invention, in the substrate processing apparatus according to the fifth or sixth aspect, a plurality of convex portions are provided on the attracting surface of the substrate in the electrostatic chuck.

The substrate processing apparatus according to claim 8 is characterized in that, in the substrate processing apparatus according to claim 5 or 6, the attraction surface of the substrate in the electrostatic chuck is formed smoothly.

In order to achieve the above object, an electrostatic chuck according to a ninth aspect of the present invention is an electrostatic chuck provided on a surface of a substrate mounting table for mounting a substrate on which the substrate is mounted and electrostatically attracting the substrate, And a thickness of the heat transfer space is set to 50 mu m or less, and nitrogen gas or oxygen gas is supplied as the temperature regulation gas to the heat transfer space at 3 Torr or less.

The electrostatic chuck according to claim 10 is characterized in that, in the electrostatic chuck according to claim 9, the thickness of the heat transfer space is set to 10 μm or less.

The electrostatic chuck according to claim 11 is characterized in that, in the electrostatic chuck according to claim 9 or 10, a plurality of convex portions are provided on the attracting surface of the substrate.

The electrostatic chuck according to claim 12 is characterized in that, in the electrostatic chuck according to claim 9 or 10, the attraction surface of the substrate is formed smoothly.

In order to achieve the above object, a substrate cooling method according to a thirteenth aspect of the present invention is a substrate cooling method for cooling a substrate mounted on a substrate mounting table, wherein an electrostatic chuck provided on a surface of the substrate mounting table, And a gas supplying step of supplying a temperature adjusting gas to the heat transfer space between the electrostatically chucked substrate and the electrostatic chuck while the electrostatic adsorption step is being performed, And the nitrogen gas or the oxygen gas is supplied to the heat transfer space at a temperature of not more than 3 Torr as the temperature regulation gas in the gas supply step.

The substrate cooling method according to claim 14 is characterized in that, in the substrate cooling method according to claim 13, the thickness of the heat transfer space is set to 10 μm or less.

According to the present invention, the thickness of the heat transfer space between the electrostatically adsorbed substrate and the electrostatic chuck is set to 50 m or less, the temperature regulating gas is supplied to the heat transfer space at 3 Torr or less, and the state of the temperature regulating gas shifts to the molecular flow region , And nitrogen gas or oxygen gas is supplied as the temperature adjusting gas. The heat flux in the molecular flow region of the nitrogen gas and the oxygen gas is larger than the heat flux in the molecular flow region of the helium gas. Therefore, the nitrogen gas and the oxygen gas can efficiently transmit the heat of the electrostatically adsorbed substrate to the electrostatic chuck (and further to the substrate stack) more than the helium gas. Further, the nitrogen gas and the oxygen gas are less expensive than the helium gas. As a result, even a substrate having a large volume resistivity value such as a large glass substrate can have a sufficient cooling effect, and a cooling effect of a substrate that suits the cost can be obtained.

1 is a cross-sectional view schematically showing a configuration of a substrate processing apparatus to which a substrate loading system according to an embodiment of the present invention is applied;
Fig. 2 is an enlarged cross-sectional view showing a configuration in the vicinity of a gas flow path opening on the adsorption face of the electrostatic chuck in Fig. 1; Fig.
3 is an enlarged cross-sectional view showing a modified example of an adsorption surface of the electrostatic chuck shown in Fig.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

1 is a cross-sectional view schematically showing a configuration of a substrate processing apparatus to which a substrate loading system according to an embodiment of the present invention is applied. This substrate processing apparatus performs a predetermined plasma process on a glass substrate for producing, for example, a liquid crystal display (LCD).

1, the substrate processing apparatus 10 includes a processing chamber (chamber) 11 for accommodating a rectangular glass substrate (hereinafter simply referred to as "substrate" . A substrate mounting table (susceptor) 12 for mounting a substrate G is disposed below the interior of the chamber 11 in the figure. The susceptor 12 has a substrate 13 having a convex section of a cross section made of, for example, aluminum or stainless steel whose surface is anodized, and an electrostatic chuck 14 disposed on the substrate 13. The electrostatic chuck 14 has an electrostatic electrode plate 15 which is formed by coating the upper portion of the substrate 13 with ceramic spray and is sandwiched between the upper dielectric layer and the lower dielectric layer in the dielectric layer formed of the ceramic spray .

A direct current power supply 17 is connected to the electrostatic electrode plate 15 inside the electrostatic chuck 14. When a definite direct current voltage is applied to the electrostatic electrode plate 15, The electric charge generated in the substrate G is neutralized when the substrate G mounted on the electrostatic chuck 14 is polarized due to the electric field generated between the substrate G and the substrate G. As a result, The substrate G is electrostatically attracted to the electrostatic chuck 14 by the Coulomb force generated between the back surface of the substrate G and the electrostatic electrode plate 15 between the substrate W and the electrostatic electrode plate 15. Hereinafter, in the present embodiment, the surface of the electrostatic chuck 14 opposed to the electrostatically attracted substrate G is referred to as an attracting surface 14a.

A cooling plate 36 in which a substrate 13 and a coolant channel (not shown) for controlling the temperature of the substrate G mounted on the electrostatic chuck 14 are provided inside the substrate 13 . A coolant such as cooling water or Galden (registered trademark) is circulated and supplied to the refrigerant passage, and the susceptor 12 is cooled by the refrigerant.

A gas flow path 18 through which a temperature adjusting gas flows is provided in the substrate 13 and the gas flow path 18 is connected to a temperature regulating gas supply device 19 provided outside the chamber 11 While being passed through the electrostatic chuck 14 and opened at a plurality of positions on the attracting surface 14a. The temperature regulating gas supplied by the temperature regulating gas supply device 19 is supplied to the heat transfer space T between the substrate G and the electrostatic chuck 14 electrostatically adsorbed through the gas flow path 18 (gas supply system) 2). The temperature regulating gas supplied to the heat transfer space T is subjected to a predetermined plasma treatment to transfer the heat of the substrate G rising in temperature to the cooled susceptor 12 so that the temperature of the substrate G And maintained at a predetermined temperature.

Fig. 2 is an enlarged cross-sectional view showing a configuration in the vicinity of a gas flow path opened on the adsorption face in Fig. 1;

In Fig. 2, a plurality of convex portions are provided on the attracting surface 14a of the electrostatic chuck 14. More specifically, a plurality of cylindrical protrusions 14b are provided on the adsorption face 14a, and when the substrate G is electrostatically adsorbed, the protrusions 14b come into contact with the back surface of the substrate G. [ Each gas flow passage 18 is opened at the non-projection surface 14d existing between the respective projection portions 14b. In the present embodiment, a space between the back surface of the substrate G and the non-projection surface 14d is referred to as a heat transfer space T. The temperature adjusting gas flowing from the opening 18a of the gas flow passage 18 spreads in the heat transfer space T and finally comes into contact with the entire back surface of the substrate G. [ The thickness t in the vertical direction in the figure of the heat transfer space T is set to 50 탆 or less, preferably 10 탆 or less, for reasons to be described later.

1, the substrate 13 is provided with a shield ring 16 as a ring-shaped shield member so as to surround the periphery of the electrostatic chuck 14. The shield ring 16 is made of, for example, And a plurality of long bodies made of ceramics.

On the side surface of the substrate 13, an insulating ring 34 as a side ring-shaped shield member is disposed to cover the side surface. The insulating ring 34 is made of insulating ceramics, for example, alumina. An insulator 35 is arranged below the substrate 13 so as to be interposed between the cooling plate 36 and the bottom surface of the chamber 11.

A high frequency power source 20 for supplying a high frequency power is connected to the base material 13 of the susceptor 12 through a matching device 21. From the high frequency power source 20, high frequency power is supplied to the substrate 13, and the susceptor 12 functions as a lower electrode. The matching device 21 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.

In the substrate processing apparatus 10, the lateral exhaust path 22 is formed by the inner wall of the chamber 11 and the side surface of the susceptor 12. The side air exhaust path 22 is connected to the exhaust device 24 through an exhaust pipe 23. A TMP (Turbo Molecular Pump), DP (Dry Pump), or MBP (Mechanical Booster Pump) as the exhaust device 24 evacuates the inside of the chamber 11 to decompress. Specifically, the DP or MBP decompresses the chamber 11 from the atmospheric pressure to a medium vacuum state (for example, 1.3 × 10 Pa (0.1 Torr) or less), and the TMP cooperates with the DP or MBP in the chamber 11 The pressure is reduced to a high vacuum state (for example, 1.3 × 10 ^-3 Pa (1.0 × 10 ^-5 Torr) or less) which is lower than the medium vacuum state. Further, the pressure in the chamber 11 is controlled by an APC valve (not shown).

In the ceiling portion of the chamber 11, a shower head 25 is disposed so as to face the susceptor 12. The showerhead 25 has an inner space 26 and a plurality of gas holes 27 for discharging the processing gas into the processing space S between the susceptor 12 and the susceptor 12. The showerhead 25 is grounded and constitutes a pair of parallel flat electrodes together with the susceptor 12 functioning as a lower electrode.

The shower head 25 is connected to the process gas supply device 29 through a gas supply pipe 28. The gas supply pipe 28 is provided with an on-off valve 30 and a mass flow controller 31. The substrate transfer port 32 is formed in the side wall of the chamber 11 so that the substrate transfer port 32 can be opened and closed by a gate valve 33, (G) is carried in and out.

In the substrate processing apparatus 10, the process gas is supplied from the process gas supply device 29 through the gas supply pipe 28. The supplied processing gas is introduced into the processing space S of the chamber 11 through the inner space 26 and the gas hole 27 of the shower head 25. The introduced processing gas is supplied to the high frequency power source 20, And is excited by the plasma generating high-frequency power supplied from the susceptor 12 to the processing space S to become plasma. Positive ions in the plasma are attracted toward the substrate G and subjected to a predetermined plasma treatment with respect to the substrate G.

The operation of each component of the substrate processing apparatus 10 is controlled by a CPU of a control unit (not shown) included in the substrate processing apparatus 10 according to a program corresponding to a predetermined plasma process.

In the substrate processing apparatus 10, the susceptor 12, the electrostatic chuck 14, and the gas flow path 18 constitute a substrate processing system.

Since the glass substrate, which is the substrate G, has a large volume resistivity value, the electrostatic attraction force acting on the substrate G is a Coulomb force rather than a Johnson-Bebe effect. Normally, since the Coulomb force is weaker than the Johnson-Bebeck force, the substrate G can not be strongly electrostatically attracted. As a result, in order to prevent the substrate G from floating from the electrostatic chuck 14, in the substrate processing apparatus 10 of Fig. 1, the pressure of the temperature adjusting gas supplied to the heat transfer space T is relatively low, Is set to about 3 Torr or less.

For example, when He gas is used as the temperature regulating gas and the supply pressure of the He gas is 3 Torr, the mean free path (?) Changed by the pressure becomes 6.08 × 10 ^-5 m in the helium molecule And the thickness t of the heat transfer space T is 50 占 퐉, the Knudsen number K represented by the following equation (1), which is an index of the He gas flow state, becomes 1.216. Further, d in the following equation (1) is the thickness (t) of the heat transfer space (T).

In general, when the kneader count K is less than 0.01, the flow state of the gas is in the viscous flow region, and when the kneader count K is larger than 0.3, the gas flow state is the molecular flow region, In the range of 0.01 to 0.3, it can be considered that the gas flow state is in the intermediate flow region. Therefore, when the thickness t of the heat transfer space T is 50 mu m and the supply pressure is 3 Torr, the flow state of the He gas can be considered to be in the molecular flow region. Further, the flow state of the gas is not clearly divided by the boundary value of the Knudsen's number, but the flow state of the gas is continuously changed in the vicinity of the boundary value into the viscous flow region, the intermediate flow region and the molecular flow region Goes. Therefore, the flow state of the gas is such that all the gas molecules are not uniformly present in the same molecular flow region when the Knudsen number exceeds 0.3, but the nature as a molecular flow region becomes stronger as the Knudsen number increases.

When the supply pressure of the inert gas other than He gas such as oxygen (O ₂ ) gas, nitrogen (N ₂ ) gas, xenon (Xe) gas and krypton (Kr) gas is 3 Torr, The mean free path of the molecules is shown in Table 1 below.

The knotsune number K of each gas in the case where the thickness t of the heat transfer space T obtained based on the above-mentioned formula (1) is 50 탆 is as shown in the following Table 2, Is about 0.3. Therefore, in the case where the thickness t of the heat transfer space T is 50 mu m and the supply pressure is 3 Torr, both the O ₂ gas, the N ₂ gas, the Xe gas, and the Kr gas have a flow state, It can be said that it is in.

As the flow state of the gas shifts from the viscous flow region to the molecular flow region, the heat flux which is the amount of heat transferred from the substrate G to the electrostatic chuck 14 by the gas is lowered. In the molecular flow region, (q) is expressed by the following equation (2).

Where T is the temperature of the adsorption surface 14a in this embodiment), To is the gas molecule temperature (in this embodiment, Is the temperature of the temperature regulating gas heated by the substrate G, and the free molecular heat transfer coefficient? Is expressed by the following equation (3).

Here,? Is a specific heat ratio, k is a gas constant, m is a molecular weight, and T '= (T + To) / 2.

The thermal adaptation coefficient alpha is an index of the heat exchange efficiency of each gas and is different depending on the state of the gas molecules and the surface of the object on which the gas molecules collide (the adsorption surface 14a in this embodiment) But it is specifically shown in Table 3 below [Sho Yugabou, Oath of Physics (11) "Physics and Applications of Vacuum", Hiroko Kuma, Hiroshi Kuma, Tomino Nagoro, Yuzo Tsuji, Horikoshi did].

The specific heat ratio γ and the molecular weight (m) of the respective gases are shown in Table 4 below, when the surface temperature T is 20 ° C., the gas molecule temperature To is 60 ° C., and the gas supply pressure p is 3 Torr As shown in Fig. In addition, the gas constant k is constant regardless of the kind of gas, and its value is 8.31 [J / k · mol].

As described above, the heat flux W / m ² of each gas in the case where the thickness t of the heat transfer space T determined based on the above-mentioned expressions (2) and (3) is 50 μm and the supply pressure is 3 Torr, 5.

The knotsune number K of each gas when the thickness t of the heat transfer space T is 10 mu m and the supply pressure is 3 Torr is shown in Table 6 below, (2) and (3), the heat flux q of the gas or the free heat transfer coefficient Λ of the gas can be obtained by dividing the thickness of the heat transfer space T t is not used as a variable, if the supply pressure is 3 Torr and the flow state of each gas is in the molecular flow region, the heat flux of each gas is equal to the heat flux shown in Table 5 above.

As shown in Table 5, the heat fluxes of the N ₂ gas and the O ₂ gas in the molecular flow region are larger than the heat fluxes of the He gas, Xe gas and Kr gas in the molecular flow region. When the supply pressure becomes smaller, the average free path (?) Of the gas molecules generally becomes larger, and the knoechene water (K) also becomes larger, so that the flow state of the gas becomes easier to shift to the molecular flow region. Further, as the thickness t of the heat transfer space T becomes smaller, the flow rate of the gas becomes easier to shift to the molecular flow region because the knoechene water K becomes larger.

Therefore, it can be said that the heat flux of the N ₂ gas and the O ₂ gas is higher than the heat fluxes of the He gas, the Xe gas and the Kr gas when the thickness t of the heat transfer space T is 50 μm or less and the supply pressure is 3 Torr or less . The present invention is based on the above findings.

1, when the substrate G is subjected to a predetermined plasma process, for example, a plasma etching process on the substrate G, the pressure in the chamber 11 is first reduced to a high vacuum state The substrate G is loaded on the electrostatic chuck 14 of the susceptor 12 and the processing gas is supplied from the shower head 25 to the processing space S of the chamber 11, The pressure of the space S is controlled to a predetermined pressure, and electrostatic adsorption is performed (substrate adsorption step). At this time, N ₂ gas or O ₂ gas is supplied to the heat transfer space T from the gas flow path 18 as a temperature regulating gas at ₃ Torr or less (gas supply step). The thickness t of the heat transfer space T is set to 50 mu m or less by each protruding portion 14b.

Subsequently, high-frequency power is supplied from the high-frequency power source 20 to the processing space S through the susceptor 12. As a result, plasma is generated from the process gas, and the desired plasma etching process is performed on the substrate G by positive ions or radicals in the plasma. The heat of the substrate G is transferred to the susceptor 12 by N ₂ gas or O ₂ gas supplied to the heat transfer space T while the plasma etching process is performed, And is maintained at a predetermined temperature or lower.

Subsequently, after the plasma etching process is finished, the supply of N ₂ gas or O ₂ gas to the heat transfer space T is stopped, and electrostatic attraction of the substrate G by the electrostatic chuck 14 is stopped The processing is terminated.

According to the substrate processing apparatus of the present embodiment, the thickness t of the heat transfer space T between the electrostatically attracted substrate G and the electrostatic chuck 14 is set to 50 μm or less, the temperature regulating gas is 3 Torr or less And the state of the temperature regulating gas shifts to the molecular flow region, but N ₂ gas or O ₂ gas is supplied as the temperature regulating gas. Is equal to or smaller than the thickness (t) of the heat transfer space (T) 50㎛, the supply pressure is below 3Torr, heat flux of N ₂ gas or O ₂ gas is greater than the flux of He gas. Therefore, the N ₂ gas or the O ₂ gas can transmit the heat of the electrostatically attracted substrate G to the electrostatic chuck 14 (and hence the susceptor 12) more efficiently than the He gas. Further, the N ₂ gas and the O ₂ gas are less expensive than the He gas. As a result, even if the substrate has a large volume resistivity value such as a large glass substrate, it is possible to obtain a sufficient cooling effect and a cooling effect of the substrate G that is cost-effective.

In the substrate processing apparatus 10, since the plurality of protruding portions 14b are provided on the attracting surface 14a of the electrostatic chuck 14, N ₂ gas or O ₂ gas exists between the protruding portions 14b And easily diffuses to the entire surface of the adsorption face 14a through the heat transfer space T which is formed by the heat transfer area T. As a result, the entire surface of the substrate G can be surely and uniformly cooled.

In the above-described substrate processing apparatus 10, the thickness t of the heat transfer space T is set to 50 m or less, but preferably the thickness t is set to 10 m or less. The Coulomb force acting on the substrate G when the thickness t of the heat transfer space T is 10 mu m is about 1.5 times the coulomb force when the thickness t of the heat transfer space T is 50 mu m The substrate G can be partially lifted by the pressure of the N ₂ gas or the O ₂ gas supplied to the heat transfer space T, Can be prevented. As a result, the thickness of the heat transfer space T can be uniformly maintained over the entire surface of the substrate G. [ In the case where the gas supplied to the heat transfer space T is He gas, the same attraction force can be obtained when the thickness t is 10 mu m or less. However, as can be seen from Tables 2 and 6, It is expected that the Knudsen number of the He gas at 10 탆 is greater than the Knudsen number of the other gas so that the nature of the molecular flow region becomes much stronger in the He gas and the property of deteriorating the heat transfer effect becomes more conspicuous. Therefore, in the case of the He gas, even if the attraction force of the substrate G by the electrostatic chuck 14 is improved, it is not preferable from the viewpoint of temperature adjustment of the substrate G. [

The thickness t of the heat transfer space T may be larger than 0 in view of the essence of the present invention. However, since there are limitations in practical processing techniques of the apparatus, the thickness t must be at least a predetermined value none.

In the above-described substrate processing apparatus 10, the case where nitrogen gas or oxygen gas is used as the temperature adjusting gas has been described. However, even if the amount of the temperature adjusting gas is too small, It is preferable to use a nitrogen gas having a lower influence on the processing of the substrate G as the temperature adjusting gas.

The present invention has been described using the above embodiments, but the present invention is not limited to the above embodiments.

A plurality of convex portions are provided on the attracting surface 14a of the electrostatic chuck 14 in the above-described substrate processing apparatus 10, but as shown in Fig. 3, the attracting surface 14a of the electrostatic chuck 14 It may be formed smoothly. In this case, the adsorbing surface 14a and the back surface of the substrate G are provided with a spacer (for example, a spacer having a thickness of 50 mu m or less) interposed between a part of the space between the adsorption surface 14a and the back surface of the substrate G, It is possible to easily form the electrostatic chuck 14 and to suppress the manufacturing cost of the electrostatic chuck 14. In this case,

Although the above-described substrate processing apparatus 10 performs the predetermined plasma processing on the substrate G, the apparatus to which the present invention is applicable is not limited to the plasma processing apparatus. For example, the substrate G may be subjected to heat treatment The present invention can be applied to any apparatus that performs other processing as long as it is an apparatus for electrostatically adsorbing and cooling the substrate G.

Example

Next, an embodiment of the present invention will be described.

First, as Embodiment 1, N ₂ gas is used as the temperature regulation gas in the substrate processing apparatus 10 having a plurality of protruding portions 14b on the adsorption surface 14a, and the thickness t of the heat transfer space T The supply pressure of the N ₂ gas to the heat transfer space T is set to ₂ Torr (267 Pa), O ₂ gas is introduced as the process gas into the process space S, and the pressure of the process space S is set to And the substrate G is subjected to plasma etching treatment by supplying the high frequency power of 4500 W from the high frequency power supply 20 to the processing space S over 120 seconds from the high frequency power supply 20, ), And the temperature of the peripheral portion was measured. The results are shown in Table 7 below.

In Example 2, the plasma etching treatment was performed on the substrate G under the same conditions as in Example 1, except that the supply pressure of the N ₂ gas to the heat transfer space T was set to 3 Torr. The temperature of the central portion and peripheral portion of the substrate G was measured and the leakage amount of N ₂ gas from the heat transfer space T to the processing space S was also measured.

The substrate G was subjected to the plasma etching treatment under the same conditions as in Example 1 except that He gas was used as the temperature adjusting gas as Comparative Example 1. The temperature of the central portion and the periphery of the substrate G And the results are shown in Table 7 below.

In Comparative Example 2, the substrate G was irradiated with plasma (plasma) under the same conditions as in Example 1, except that He gas was used as the temperature adjusting gas and the He gas supply pressure to the heat transfer space T was set to 3 Torr The temperature of the central portion and the peripheral portion of the substrate G in the case where the etching process was performed and the leakage amount of the N ₂ gas from the heat transfer space T to the process space S were measured and shown in Table 7 .

As shown in Table 7, when the supply pressures were the same in the case of using N ₂ gas as the temperature adjusting gas (Examples 1 and 2) and the case of using He gas (Comparative Examples 1 and 2) (G) was almost the same, but it was found that the use of N ₂ gas was lower. Particularly, in the comparison between the case where the property of the molecular flow region is stronger and the case where the pressure is low (Example 1 performed with 2 Torr and Comparative Example 1), the N ₂ gas has a remarkably higher cooling effect. As a result, it has been found that the use of N ₂ gas as the temperature adjustment gas can provide a cooling effect for the substrate G that is cost-effective.

Further, the leakage amount is smaller in the N ₂ gas than in the He gas. When the leakage amount is small, the pressure distribution of the temperature adjusting gas in the heat transfer space T is stabilized, and the substrate G can be uniformly cooled over the entire surface. It is presumed that the leakage amount of the N ₂ gas is small because the molecular diameter of the N ₂ molecule is larger than the molecular diameter of the He molecule and the N ₂ molecule is difficult to flow out from the minute gap existing around the heat transfer space T. From this point also, it has been found that it is preferable to use N ₂ gas rather than He gas as the temperature regulating gas.

G: substrate
T: Heat transfer space
10: substrate processing apparatus
11: chamber
12: susceptor
14: electrostatic chuck
14a: adsorption face
14b:
18: gas channel

Claims (14)

An electrostatic chuck installed on a surface of the substrate stacking table on which the substrate is to be placed and electrostatically adsorbing the substrate; a temperature adjustment unit for adjusting a temperature in the heat transfer space between the electrostatically chucked substrate and the electrostatic chuck; A substrate cooling system comprising a gas supply system for supplying a gas,
The thickness of the heat transfer space is set to 10 mu m or less,
Wherein the gas supply system supplies nitrogen gas or oxygen gas as the temperature regulation gas to the heat transfer space at 3 Torr (400 Pa) or less. delete The substrate cooling system according to claim 1, wherein a plurality of convex portions are provided on the attracting surface of the substrate in the electrostatic chuck. The substrate cooling system according to claim 1, wherein the attracting surface of the substrate in the electrostatic chuck is formed to be smooth. And a substrate stacking table disposed on the surface of the substrate stacking table on which the substrate is stacked to stack the substrate, A substrate processing apparatus comprising: an electrostatic chuck to be adsorbed; and a gas supply system for supplying a temperature adjusting gas to a heat transfer space between the electrostatically chucked substrate and the electrostatic chuck,
The thickness of the heat transfer space is set to 10 mu m or less,
Wherein the gas supply system supplies nitrogen gas or oxygen gas as the temperature regulation gas to the heat transfer space at 3 Torr or less. delete The substrate processing apparatus according to claim 5, wherein a plurality of convex portions are provided on the attracting surface of the substrate in the electrostatic chuck. The substrate processing apparatus according to claim 5, wherein the attracting surface of the substrate on the electrostatic chuck is formed to be smooth. An electrostatic chuck provided on a surface of a substrate mounting table for mounting a substrate on which the substrate is mounted to electrostatically adsorb the substrate,
A heat transfer space is formed between the substrate and the electrostatically adsorbed substrate,
The thickness of the heat transfer space is set to 10 mu m or less,
Characterized in that nitrogen gas or oxygen gas is supplied to the heat transfer space as a temperature regulating gas at 3 Torr or less. delete The electrostatic chuck according to claim 9, wherein a plurality of convex portions are provided on the attracting surface of the substrate. The electrostatic chuck according to claim 9, wherein an adsorption surface of the substrate is formed to be smooth. A substrate cooling method for cooling a substrate mounted on a substrate mounting table,
An electrostatic chuck provided on a surface on which the substrate is mounted on the substrate table, electrostatically attracting the substrate;
And a gas supplying step of supplying a temperature adjusting gas to the heat transfer space between the electrostatically attracted substrate and the electrostatic chuck while the electrostatic adsorption step is executed,
The thickness of the heat transfer space is set to 10 mu m or less,
Wherein the gas supply step supplies nitrogen gas or oxygen gas as the temperature regulation gas to the heat transfer space at 3 Torr or less. delete

Images