JPH11204514A - Gas processing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To allow ammonia gas flow in an aging unit to be even for a good quality film when a coat liquid, wherein TEOS(tetraethoxysilane) for example, colloid is diffused in a solvent is coated on a semiconductor wafer by a coating unit, the colloid in the coated film is gelled by the again unit, and the solvent in the coated film is substituted with another solvent by a solvent substitution unit for obtaining an interlayer insulating film of silicon oxide film. SOLUTION: A slit-like gas guide opening 34a is provided outside a wafer W, and a straightening member 32 comprising a straightening surface part 37a which faces a surface to be processed of the wafer W, is so tilted as to become more distant from the wafer W when approaching the center part of a closed vessel, a protruding part 37c a region nearer to the center expanding downward, and a partition part 37b, which enclosing the side of the wafer W, forms a buffer chamber 38 outside of it, is provided in the closed vessel, for forming a uniform gas flow along the surface of the wafer W.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gas processing apparatus for processing a coating film applied to, for example, a semiconductor wafer with a gas in a closed container.

[0002]

2. Description of the Related Art As a method for forming an interlayer insulating film of a semiconductor device, there are a CVD method, a thermal oxidation method, and the like, and another method called a sol-gel method. This method can be performed, for example, using TEOS (tetraethoxysilane; Si (C
A coating solution in which a colloid of 2 H5 O) 4) is dispersed in an organic solvent such as an ethanol solution is applied to the surface of a semiconductor wafer (hereinafter simply referred to as a wafer), and the coating film is gelled and dried to form a silicon oxide film. Is a technique for obtaining
-162450 and JP-A-8-59362.

FIG. 9 schematically shows a state of modification of a coating film in this method. First, when a coating liquid is applied to a wafer, TEOS particles or colloid 100 is dissolved in solvent 2.
00 (see FIG. 9A), and then the TE film is exposed, for example, by exposure to an alkaline atmosphere or by heating.
As the OS undergoes polycondensation and hydrolysis, the coating film gels, forming a network structure of TEOS 300 (FIG. 9).
(B)). Then, the solvent in the coating film is replaced with another solvent 400 such as acetone to remove the water in the coating solution (see FIG. 9C), and then dried to obtain a coating film of a silicon oxide film. In the solvent replacement step shown in FIG. 9C, in addition to the purpose of removing water, a solvent having a lower surface tension than ethanol is used, and a large force is applied to the TEOS network structure when the solvent evaporates. There is also a purpose of suppressing the collapse of the structure of the film by eliminating it.

In order to apply such a sol-gel method to an actual production line, a coating unit for applying a coating liquid to a wafer, for example, for bringing an ammonia gas into contact with the wafer, or a wafer at a predetermined temperature (for example, 10
An aging unit for heating to about 0 ° C.) to gel the coating film and a replacement unit for replacing the solvent in the coating film with another solvent are required.

In order to perform the gelling process, the inventor places a wafer W on a plate 61 and covers the plate 61 with a cylindrical lid 62 as shown in FIG. Gas introduction path 63 on the periphery of plate 61
Is being studied to supply ammonia gas from the exhaust port 64 at the center of the lid 62.

[0006]

In the unit having the structure shown in FIG. 10, the ammonia gas tends to flow upward from the gas supply port of the plate 61 along the inner peripheral surface of the lid 62 from the bottom. Exhaust passage 64 at the center of 61
The gas is drawn into the exhaust passage 64 by the suction force of the above, and a flow which is directed obliquely upward is formed. Here, the gas flowing upward from below along the inner peripheral surface of the lid 62 becomes a vortex at the upper corner, and does not smoothly descend downward. For this reason, the gas flow rate and the gas concentration in the central portion are smaller than those in the peripheral portion of the wafer W, so that the progress of gelation varies, and
As a result, there is a problem that an inhomogeneous film is formed.

The present invention has been made under such circumstances, and an object of the present invention is to enable processing of a substrate such as a wafer in a closed vessel under a uniform gas flow, thereby improving quality. It is an object of the present invention to provide a technique capable of obtaining a thin film such as an interlayer insulating film.

[0008]

According to a first aspect of the present invention, there is provided an airtight container for processing a substrate in the presence of a gas, and a mounting portion provided in the airtight container for mounting the substrate. A rectifying surface portion having an inclined surface portion facing the surface to be processed of the substrate placed on the mounting portion and being inclined away from the substrate toward the center of the closed container, and a peripheral portion of the rectifying surface portion. A gas introduction port provided along, and an exhaust port provided at a central portion of the closed vessel facing the surface to be processed of the substrate placed on the placement section, wherein the gas is provided. Processing device. In this case, it is preferable that the rectification surface portion has a convex portion when viewed in a vertical section. Further, a configuration may be provided that includes a buffer chamber formed radially outside the airtight container in the rectifying surface portion and communicating with the gas introduction port, and a gas introduction passage for introducing gas into the buffer chamber.

According to a fourth aspect of the present invention, there is provided an airtight container for processing a substrate in the presence of a gas, a mounting portion provided in the airtight container for mounting the substrate, A partition that surrounds the side of the space facing the processing surface of the mounted substrate and is provided to form a buffer chamber outside the space, and the same height level as the substrate in the buffer chamber or the same. A gas inlet formed to communicate with the space at a height level in the vicinity, a gas introduction path for introducing gas into the buffer chamber, and processing of the substrate mounted on the mounting portion. A gas exhaust device provided with an exhaust port provided at a central portion of the closed container facing the surface.

Preferably, the gas inlet is formed in a slit shape along the circumferential direction of the closed container. The airtight container has, for example, a configuration including a first member provided with a mounting portion, and a second member provided with a rectifying surface portion and capable of coming into contact with and separating from the first member. The gas introduction path is provided, for example, through the first member.

The substrate is, for example, a substrate on which a coating liquid in which particles or colloids of a starting material of a film forming component are dispersed in a solvent is applied to form a coating film. This is a treatment using a gas for promoting gelation of particles or colloids, for example, an alkaline gas. According to the above configuration, since a uniform gas flow is formed along the surface of the substrate, uniform processing, for example, uniform gelation processing can be performed over the entire substrate, and for example, a high-quality insulating film can be obtained. it can.

[0012]

FIG. 1 is a plan view schematically showing an entire configuration of an example of a coating film forming apparatus including a gas processing apparatus according to the present invention. Reference numeral 11 denotes an input / output port for a wafer serving as a substrate, from the cassette C placed on the cassette stage CS.
The transfer arm 12 takes out the wafer W and transfers it to the main arm 13. Main arm 1
3 is provided on one side of a conveying path (guide rail) 14 with a coating unit 2 which is a coating unit which is a main part of the present embodiment.
Are arranged in this order together with the aging unit 3 which is a gelling unit and the solvent replacing unit 4 which is a solvent replacing unit. Processing units U1 to U4 are also arranged on the other side of the transport path 14, and these processing units U
For units 1 to U4, units for performing a hydrophobizing process before applying the coating liquid to the substrate, a cooling process, and a heat treatment (baking process) after forming a coating film on the substrate are respectively assigned.

The overall operation of the coating film forming apparatus will be briefly described. The unprocessed wafer W taken out of the cassette C of the cassette stage CS by the main arm 13 is stored in the coating unit 2. Then, in the coating unit 2, a coating liquid T in which a colloid or particle of TEOS is dispersed in a solvent is dropped on the surface of the wafer W (FIG. 2A), and the wafer W is rotated at a high speed to rotate the coating liquid T.
Spreads on the wafer surface to form a coating film F (FIG. 2).
(B)) Next, the wafer W is placed on the heating plate 31 of the aging unit 3 and sealed by the lid 33. Then, an alkaline gas such as an ammonia gas is introduced into the aging unit 3 to gel the coating film (FIG. 2C).

Thereafter, in the solvent replacement unit 4, FIG.
As shown in (d), the solvent of the gelled coating film is replaced with ethyl alcohol, HMDS (hexamethyldisilane) and heptane. Thereby, the water in the coating film is replaced with ethyl alcohol. Further, the hydroxyl groups in the coating film are removed by HMDS. Further, the solvent in the coating film is replaced with heptane. The reason for using heptane is to reduce the force applied to the porous structure, that is, the network structure of TEOS by using a solvent having a small surface tension so that the structure does not collapse. Thereafter, the wafer W is baked in a baking unit for, for example, one minute, and an interlayer insulating film made of a silicon oxide film is formed on the surface of the wafer W.

Next, this embodiment will be described. FIG.
(A) shows an example of the aging unit (gelling unit) 3 which is an embodiment of the gas treatment apparatus of the present invention. As shown in FIG. 1, the aging unit 3 includes a plate 31 on which a wafer W is mounted, and a sealing container together with the plate 31 which is closely attached to a peripheral portion of the plate 31 via a sealing member 32. And a lid 33
A gas introduction path 34 communicated with the inside of the sealed container via a gas introduction port 34a opened on the surface of the gas inlet 31;
Rectifying member 37 for making the flow of gas introduced from a uniform
And an exhaust path 35 in which an exhaust port 35 a is formed in the center of the lid 33 and the flow regulating member 37. Further, the aging unit 3 is provided with, for example, three lifting pins 36 for raising and lowering the wafer W between the plate 31 and a position above the plate 31. The rectifying member 37 is attached to the inner surface of the lid 33, and has a rectifying surface portion 37a facing the surface to be processed of the wafer W, that is, the upper surface on which the coating film is applied.
The gas inlet 34a is provided in a slit shape along the peripheral edge of the flow regulating surface 37a and along the circumferential direction of the sealed container.

Accordingly, the gas is uniformly introduced into the closed container from the peripheral portion of the wafer W and discharged from the exhaust port 35a.
If the gas inlet is formed of several holes instead of a slit, the arrangement of the holes may affect the thickness of the coating film. It is preferable to make the shape. The gas inlet may be constituted by a large number of holes so that the transfer of the arrangement pattern of the gas inlet holes does not occur.

The rectifying surface portion 37a has an inclined surface portion 37b that is inclined so as to move away from the surface of the wafer W as going from the peripheral portion of the wafer W to the center of the closed container. In the example shown in FIG. 3, for example, the rectifying surface portion 37 a is temporarily moved from the peripheral portion of the wafer W to the center portion of the closed container.
, The rectifying surface portion 37a bulges downward at the center portion surrounding the exhaust port 35a so as to approach the wafer W again. That is, when the rectification surface portion 37a is viewed in a longitudinal section, the convex portion 37c is formed in a peripheral region surrounding the exhaust port 35a of the rectification surface portion 37a.

In the example shown in FIG.
Reference numeral 7 denotes a partition 37b for surrounding a space S serving as a processing chamber between the rectifying surface 37a and the surface to be processed of the wafer W, and forming a peripheral buffer chamber 38 outside the space S. ing. The partition part 37b is connected to the rectifying surface part 37a at the lower end thereof, and is connected to the lower end by the plate 31.
A gap for introducing gas into the processing chamber is formed over the entire circumference. This gap is a gas inlet as viewed from the processing chamber, and corresponds to the gas inlet in the claims.

The buffer chamber 38 communicates with the gas inlet 34a, and the wafer W
In the vicinity of the surface. As a result, the gas introduced into the buffer chamber 38 from the gas inlet 34a
The wafer W flows laterally into the processing chamber (space S) from the side of the wafer W toward the center of the processing chamber.

The gas introduction path 34 is provided through the plate 31, and a dispersion chamber 30 for dispersing the gas is formed in the middle of the gas introduction path 34. The gas is dispersed here, and the gas is dispersed into a slit-shaped gas. It is introduced into the closed container from the inlet 34a. Although the number of gas introduction paths 34 to the dispersion chamber 30 is one for convenience of illustration, a plurality of, for example, three pipes may be provided.

Next, the operation of the aging unit 3 having the above structure will be described. After being conveyed from the coating unit 2 by, for example, the main arm 13 and placed on the plate 31 via the elevating pins 36, the lid 33 Is closed. Then, as shown in FIG. 3B, for example, ammonia gas is once introduced into the buffer chamber 38 from the gas introduction port 34a,
From here, the wafer W flows into the processing chamber from the side of the wafer W. The gas introduction port 34a opens upwardly. However, since the gas is once introduced into the buffer chamber 38 and then flows into the space S serving as a processing chamber from the side, the gas introduction port 34a is positioned from the wafer periphery to the central portion. A lateral flow is formed towards. While this gas spreads up and down, the exhaust port 35 at the upper center of the processing chamber
First, the gas that is going to spread upward toward a flows smoothly inside the processing chamber along the inclined surface 37b. Subsequently, this gas is directed toward the wafer W by the convex portion 37c near the exhaust port 35a, so that the gas is prevented from flowing into the vicinity of the center of the wafer from the upper side and becoming lean, and the wafer W is viewed as a whole. A uniform gas flow along the surface is formed.

By supplying the ammonia gas to the surface of the wafer W in this way, the process of gelling the TEOS colloid contained in the coating film and chaining it in a network is promoted. Ammonia gas is TEOS as an alkaline catalyst.
It is not always necessary to perform heating because it acts on and promotes gelation, but heating may be performed. According to the above-described embodiment, since a uniform gas flow is formed along the surface of the wafer W, a uniform gelling process can be performed on the uniform wafer, and therefore, a good quality thin film, for example, an interlayer insulating film is obtained. be able to.

The gas introduced from the gas inlet 34a is ammonia gas in this example. However, in order to suppress evaporation of the solvent in the coating film, a vapor of a solvent, for example, a vapor of ethylene glycol is also introduced. Is also good. Further, the above-mentioned gelling treatment may be promoted by heating the wafer to, for example, 100 ° C. without using ammonia gas. In this case, in order to suppress evaporation of the solvent in the coating film, for example, ethylene glycol is used. For example, it is necessary to introduce the wafer vapor on a plate having a built-in heater.
The temperature of the piping, the steam generation source, and the like is adjusted so that the steam becomes saturated steam. In this way, the vapor of ethylene glycol spreads sufficiently to the center of the wafer, so that unevenness in evaporation of the solvent from the coating film can be suppressed.

The rectifying member is not limited to the rectifying member shown in FIG. 3, but may be a buffer chamber 3 like the rectifying member 51 shown in FIG.
The rectifying surface portion 51a following the baffle plate portion 51b serving as a partitioning portion defining the portion 8 is located farthest from the wafer W at the peripheral edge portion of the wafer W, and is rectified in FIG. Like the member 37, it may be formed so that the convex portion 51c is formed. In this case, since there is no inclined surface, there is a possibility that a gas vortex may be generated slightly above the outer edge of the rectifying member 37 as compared with the example shown in FIG. 3, but otherwise the same as in the example shown in FIG. The effect is obtained and a sufficiently uniform gas flow is formed.

As shown in FIG. 5, the rectifying member 52 has a rectifying surface 52a protruding upward from the lower end of the partition 52b defining the buffer chamber 38 toward the exhaust port 35a when viewed in a longitudinal section. Or it may be convex downward). Further, as in the rectifying member 53 shown in FIG. 6, the rectifying surface portion 53a has a curved line that is linear from the lower end of the partition portion 53b defining the buffer chamber 38 toward the exhaust port 35a when viewed in a longitudinal section. May be formed. In each of these cases,
The effect of gas supply to the center of the wafer is weakened, but otherwise the same effect as in the example shown in FIG. 3 is obtained, and a sufficiently uniform gas flow is formed.

As in the rectifying member 54 shown in FIG. 7, a partition corresponding to the partition 37b in FIG. 3 may not be provided. Therefore, in the example of FIG. 7, since the buffer chamber is not provided, the effect of forming the uniform gas flow along the surface of the wafer W due to the lateral supply of the gas is slightly weakened, but otherwise the example shown in FIG. The same effect as described above is obtained, and a sufficiently uniform gas flow is formed. This rectifying member 5
The rectifying surface portion 54a of No. 4 is not particularly limited, but has, for example, the same shape as the example of FIG.

As shown in FIG. 8, the partition 3 shown in FIG.
Only the partition 55 corresponding to 7b may be provided. When the gas is directly introduced into the processing chamber without providing the partitioning portion 55, a vortex is generated at a position facing the gas inlet 24a. In this example, the gas is supplied laterally by the partitioning portion 55. Generation is suppressed, and a uniform gas flow along the surface of the wafer W is formed. In this case, the gas flow uniformity can be improved by appropriately adjusting the flow rate of the gas, the gap between the lower end of the partition portion 55 and the plate 31, and the like.

As described above, the present invention relates to the rectifying members 37, 5
1, 52, 53, 54 and the partitioning part 55 may be formed integrally with the lid 33, or the gas inlet may be provided on the side of the wafer W, for example, on the side plate part of the lid 33 or the top plate part of the lid 33. May be. The substrate is not limited to a wafer, but may be a glass substrate for a liquid crystal display. The mode of the gas treatment is not limited to the gelling process, but may be another process such as an etching process.

[0029]

As described above, according to the present invention, a substrate such as a wafer can be processed under a uniform gas flow in a closed container, and a high-quality thin film such as an interlayer insulating film can be obtained. it can.

[Brief description of the drawings]

FIG. 1 is a plan view showing an overall schematic configuration of an example of a coating film forming apparatus used for carrying out a method of the present invention.

FIG. 2 is an explanatory diagram illustrating a flow of a coating film forming process using the coating film forming apparatus.

FIG. 3 is a vertical sectional side view showing an example of an aging unit and a gas flow in the aging unit in the coating film forming apparatus.

FIG. 4 is a vertical sectional side view showing another example of the aging unit.

FIG. 5 is a vertical sectional side view showing another example of the aging unit.

FIG. 6 is a vertical sectional side view showing another example of the aging unit.

FIG. 7 is a longitudinal sectional side view showing another example of the aging unit.

FIG. 8 is a vertical sectional side view showing another example of the aging unit.

FIG. 9 is an explanatory view showing a state of denaturation of a coating film in a sol-gel method.

FIG. 10 is a longitudinal sectional side view showing an aging unit as a comparative example of the present invention.

[Explanation of symbols]

 F Coating film S Processing chamber T Coating liquid W Semiconductor wafer (substrate) 2 Coating unit 3 Aging unit 31 Placement unit 31a Heating unit 32 Seal member 33 Cover 34 Gas introduction path 34a Gas introduction port 35a Exhaust port 35 Exhaust path 36 Lifting pin 37, 51, 52, 53, 54 Rectifying member 37a, 51a, 52a, 53a, 54a Rectifying surface 37b, 51b, 52b, 53b, 55 Partition 37c, 51c Convex 38 Buffer chamber 4 Solvent replacement unit

Claims (9)

[Claims] An airtight container for processing a substrate in the presence of a gas, a mounting portion provided in the airtight container for mounting a substrate, and a substrate mounted on the mounting portion A rectifying surface portion having an inclined surface portion which is opposed to the surface to be processed and which is inclined away from the substrate toward the center of the closed container; a gas inlet provided along a peripheral portion of the rectifying surface portion; A gas processing apparatus, comprising: an exhaust port provided at a central portion of a sealed container, facing an object surface of a substrate placed on a placement section. 2. The gas processing apparatus according to claim 1, wherein the rectifying surface portion has a convex portion when viewed in a vertical cross section. 3. A buffer chamber formed radially outside of the airtight container in the rectifying surface portion and communicating with a gas introduction port, and a gas introduction passage for introducing gas into the buffer chamber. The gas processing apparatus according to claim 1 or 2, wherein 4. A closed container for processing a substrate in the presence of a gas, a mounting portion provided in the closed container for mounting a substrate, and a substrate mounted on the mounting portion. A partition portion surrounding the side of the space facing the surface to be processed, and provided so as to form a buffer chamber outside the space; and a height level at or near the same height level as the substrate in the buffer chamber. A gas introduction port formed to communicate with the space, a gas introduction path for introducing a gas into the buffer chamber, and a surface to be processed of the substrate placed on the placement section, A gas processing device, comprising: an exhaust port provided at a central portion of a closed container. 5. The gas processing apparatus according to claim 1, wherein the gas inlet is formed in a slit shape along a circumferential direction of the closed vessel. 6. An airtight container comprising: a first member provided with a mounting portion; and a second member provided with a rectifying surface portion and capable of coming into contact with and separating from the first member. The gas processing apparatus according to any one of claims 1 to 5, wherein: 7. The gas processing apparatus according to claim 6, wherein the gas introduction path is provided through the first member. 8. The substrate has a coating film formed by applying a coating liquid in which particles or colloid of a starting material of a film forming component are dispersed in a solvent, and a process performed in a closed container includes the step of: 8. The gas processing apparatus according to claim 1, wherein the processing is performed using a gas for promoting gelation of the particles or the colloid. 9. The gas processing apparatus according to claim 8, wherein the gas is an alkaline gas.