JP2000003843A - Wafer heat treatment device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a wafer heat treatment device which can prevent irregularities in temperature of a wafer. SOLUTION: A heater plate 2 is arranged inside a lower housing 1, and a cover member 15 covering the heater plate 2 is provided movably in the vertical directions on an upper surface 1a of the lower housing 1. A top plate 16 is held by a plurality of position adjustment members 19 inside the cover member 15. An interval between the top plate 16 and a wafer W on a heater plate can be adjusted arbitrarily, by adjusting the plurality of position adjustment members 19, and temperature distribution of the wafer W can be made uniform.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a substrate heat treatment apparatus for heating a substrate to a predetermined temperature.

[0002]

2. Description of the Related Art A substrate heat treatment apparatus is used in a process of processing a substrate such as a semiconductor wafer, a glass substrate for a photomask, a glass substrate for a liquid crystal display device, and a substrate for an optical disk. For example, in a photolithography process, a substrate heat treatment apparatus is used to heat a substrate on which a resist film is formed to a predetermined temperature.

FIG. 7 is a schematic diagram showing a schematic configuration of a conventional substrate heat treatment apparatus. 7, the substrate heat treatment apparatus includes a heating plate 31 inside a housing 30. A heat source such as a heater is embedded inside the heating plate 31, and three spherical spacers 38 that support the lower surface of the substrate W are formed on the upper surface.

Below the heating plate 31, three lifting pins 32 for lifting the substrate W and a lifting frame 33 connected to these pins are arranged. Elevating frame 33
A cylinder 34 is connected to one end of the cylinder 3.
The substrate W is moved up and down by three elevating pins 32 in accordance with the expansion and contraction operation of the rod 4.

A cover member 3 is provided on the upper surface of the heating plate 31.
5 are arranged. The cover member 35 is formed so as to be able to move up and down. During the heat treatment, the cover member 35 is placed on the upper surface of the heating plate 31 and the processing space 3 which is substantially closed
6 are formed.

When loading and unloading the substrate W, the cover member 35
The three lifting pins 32 are raised, and the substrate W is loaded and unloaded through the substrate supply / discharge port 37 of the housing 30.

At the time of heating the substrate W, the substrate W is held close above the heating plate 31, and the cover member 35 is placed on the upper surface of the heating plate 31. Then, the substrate W is heated from the upper surface side of the heating plate 31, and is heated to a predetermined temperature. Thereby, a predetermined heat treatment is performed on the resist film on the surface of the substrate W.

In the substrate heat treatment apparatus, it is required to uniformly heat the substrate W to a predetermined temperature. For example, a heat treatment (PEB: Post Exposur) after the exposure treatment
In the eBake process, it is extremely important to heat the entire substrate to a uniform temperature in order to make the line width of the pattern formed on the resist by exposure. In particular, in recent years,
Exposure processes using excimer lasers have been developed to form finer patterns. In this excimer process, a chemically amplified resist is used. In the exposure process using a chemically amplified resist, an acid catalyst is generated in the resist film by an excimer laser, and the generated acid catalyst is heated and diffused by PEB treatment using a substrate heat treatment apparatus, thereby accelerating the reaction. To form a simple pattern. For this reason, in the heat treatment using the chemically amplified resist, it is particularly required to make the temperature distribution of the substrate W uniform.

[0009]

However, in the conventional substrate heat treatment apparatus, when the substrate supply / discharge port 37 is opened at the time of loading and unloading the substrate, and the upper cover 35 is raised,
Outside air enters the processing space 36, and the temperature distribution in the processing space 36 is disturbed. As a result, the temperature distribution of the substrate W may become non-uniform at the beginning of the next heat treatment of the substrate W.

When the diameter of the substrate W is increased, the amount of heat radiation from the outer peripheral portion becomes larger than the amount of heat radiation from the central portion of the substrate W. As a result, the temperature tends to be non-uniform between the central portion and the outer peripheral portion of the substrate W.

An object of the present invention is to provide a substrate heat treatment apparatus capable of preventing temperature unevenness of a substrate.

[0012]

Means for Solving the Problems and Effects of the Invention In the course of the present invention, the inventors have found that in a substantially closed processing space, the distance between the top plate and the surface of the substrate affects the temperature distribution of the substrate. It was found that it was given, and various studies were made.
As a result, the following invention has been devised.

A substrate heat treatment apparatus according to a first aspect of the present invention is a substrate heat treatment apparatus for processing a substrate at a predetermined temperature, comprising a base having a heat source and having a support for supporting a lower surface of the substrate;
A lid member that covers the upper part of the base, a top plate disposed inside the lid member facing the substrate supported by the support part of the base, and each part of the substrate supported by the support part of the base; Adjusting means for adjusting the interval between the top plate and the opposing portion.

In the substrate heat treatment apparatus according to the first aspect of the present invention, the substrate is placed on the supporting portion of the base during processing, and the substrate is heated in a substantially sealed processing space by being covered with a lid member. . At this time, the distance between each part of the substrate and the opposing part of the top plate is adjusted to a predetermined state by the adjusting means in advance. For this reason, the temperature of the substrate is set uniformly over the entire surface, and the occurrence of processing unevenness due to the non-uniform temperature of the substrate is prevented.

According to a second aspect of the present invention, there is provided a substrate heat treatment apparatus comprising:
In the configuration of the substrate heat treatment apparatus according to the invention, the adjusting means includes a plurality of connecting members for connecting the top plate and the lid member so that the distance between the top plate and the lid member can be adjusted.

In this case, by adjusting each of the plurality of connecting members, the top plate can be arranged parallel or inclined to the substrate, or even curved. Thus, when the temperature distribution of the substrate becomes uneven due to various factors, the temperature distribution of the substrate can be made uniform by adjusting the distance between the substrate and the top plate.

A substrate heat treatment apparatus according to a third aspect of the present invention comprises
In the configuration of the substrate heat treatment apparatus according to the present invention, the plurality of connecting members are arranged so that the parallelism of the top plate with respect to the substrate supported by the support portion of the base can be adjusted.

In this case, when the influence of disturbance such as invasion of outside air is small, the temperature distribution of the substrate can be made uniform by disposing the top plate in parallel with the substrate. Also,
When the temperature distribution of the substrate becomes non-uniform due to disturbance such as invasion of the outside air, the temperature distribution of the substrate can be made uniform by disposing the top plate at an angle to the substrate.

According to a fourth aspect of the present invention, there is provided a substrate heat treatment apparatus comprising:
Alternatively, in the configuration of the substrate heat treatment apparatus according to the third invention, each of the plurality of connecting members includes a screw member.

In this case, the distance between each part of the top plate and the opposing part of the substrate can be set to an optimum state by appropriately adjusting the screw members.

According to a fifth aspect of the present invention, there is provided a substrate heat treatment apparatus comprising:
In the configuration of the substrate heat treatment apparatus according to the present invention, the outer peripheral portion of the top plate is fixed to the lid member, and the adjusting means deflects the top plate into a curved shape so that the distance between the central portion of the top plate and the central portion of the lid member. Is provided with a connecting member for connecting the top plate and the lid member so as to be adjustable.

In this case, when the temperature distribution between the central portion and the outer peripheral portion of the substrate becomes uneven due to the difference in the amount of heat radiation of the substrate,
By disposing the top plate in a curved manner, the temperature distribution of the substrate can be made uniform.

The substrate heat treatment apparatus according to the sixth aspect of the present invention includes
In the configuration of the substrate heat treatment apparatus according to the invention, the connecting member includes a screw member.

In this case, the distance between the center of the top plate and the center of the substrate can be set to an optimum state by appropriately adjusting the screw members.

[0025]

FIG. 1 is a side sectional view of a substrate heat treatment apparatus according to a first embodiment of the present invention, and FIG. 2 is a sectional view taken along line AA in FIG.

Referring to FIGS. 1 and 2, the substrate heat treatment apparatus includes an upper housing 25 and a lower housing 1. Lower housing 1
The heating plate 2 is arranged in the inside. A heat source such as a heater or a Peltier element is embedded inside the heating plate 2, and three spherical spacers 3 that support the lower surface of the substrate W are arranged in an equilateral triangle on the upper surface. The heating plate 2 is supported by a plate support frame 4,
It is fixed to the bottom surface of the lower housing 1 by a plurality of mounting members 5. The heating plate 2 is supported so that the upper surface is horizontal by adjusting the plurality of mounting members 5.

Below the heating plate 2, three lifting pins 6 and a lifting frame 7 connected to these pins are arranged. One end of the lifting frame 7 extends outside the lower housing 1 and is connected to the cylinder 10. Thus, the elevating frame 7 and the elevating pins 6 move up and down in accordance with the expansion and contraction of the rod of the cylinder 10.

A substrate supply / discharge port 26 is formed on the front surface of the upper housing 25. A shutter 9 is provided inside the substrate supply / discharge port 26.
Is arranged. The lower end of the shutter 9 is connected to the lifting frame 7 by an interlocking member 8. As a result, when the rod of the cylinder 10 is extended, the elevating frame 7 is raised to raise the substrate W above the heating plate 2, and the shutter 9 is lowered to open the substrate supply / discharge port 26. Also, when the rod of the cylinder 10 is retracted,
The elevating frame 7 is lowered, the substrate W is placed on the spherical spacer 3, and the shutter 9 is raised to close the substrate supply / discharge port 26.

A cover member 15 is provided above the heating plate 2.
Is arranged. The cover member 15 is formed in a circular lid shape that covers the upper side of the substrate W. A cover support frame 21 is attached to a side surface of the cover member 15. One end of the cover support frame 21 extends outside the upper housing 25 and is connected to the cylinder 22. When the rod of the cylinder 22 is retracted, the cover member 15 is placed on the upper surface 1a of the lower housing 1. Thus, the processing space 1 closed by the heating plate 2 and the cover member 15
2 are formed. When the rod of the cylinder 22 extends, the cover member 15 moves up. As a result, the processing space 12 is opened, and the loading and unloading of the substrate W becomes possible.

A gas inlet 18 for guiding an inert gas such as nitrogen (N ₂ ) into the processing space 12 is formed at the center of the upper surface of the cover member 15. This gas inlet 1
A gas introduction pipe (not shown) is connected to 8.

Further, a top plate 16 is provided inside the cover member 15. The top plate 16 is formed from a material such as stainless steel or aluminum. A large number of holes 17 are formed in the top plate 16. The inert gas supplied from the gas inlet 18 is uniformly supplied into the processing space 12 through the many holes 17 of the top plate 16. A plurality of exhaust holes 11 are formed on the upper surface 1 a of the lower housing 1 along the outer periphery of the heating plate 2. The inert gas supplied to the processing space 12 passes through the exhaust hole 11 and is exhausted outward from an exhaust port 1 b formed on a side surface of the lower housing 1. As a result, the inside of the processing space 12 is maintained in an inert atmosphere.

The top plate 16 is mounted on the upper surface of the cover member 15 by a plurality of position adjusting members 19. The position adjusting member 19 includes a position adjusting bolt 19a and a nut 19b. The lower end of the position adjusting bolt 19a is fixed to the upper surface of the top plate 16, and the upper end extends upward through the cover member 15. Nut 1 for position adjustment bolt 19a
9b is screwed, and the nut 19b is
The top plate 16 can be supported and fixed at an arbitrary position in the vertical direction by contacting the upper surface of the top plate. Thereby, the distance between the top plate 16 and the substrate W held close above the heating plate 2 can be arbitrarily adjusted. The method for adjusting the position of the top plate 16 will be described in detail below.

In this embodiment, the heating plate 2 corresponds to a base of the present invention, the spacer 3 corresponds to a support, the cover member 15 corresponds to a lid member, and the top plate 16 corresponds to a top plate. The position adjusting member 19 corresponds to an adjusting unit and a connecting member.

As a result of various experiments in the substrate heat treatment apparatus, it has been found that the temperature of the substrate W changes according to the distance between the substrate W and the top plate 16. FIG. 3 is a diagram showing the relationship between the distance between the substrate and the top plate and the temperature of the substrate. The horizontal axis in FIG. 3 shows the distance between the substrate W and the top plate 16, and the vertical axis shows the average temperature of the substrate W when the distance is set. Hereinafter, the intervals between the substrate W and the top plate 16 in FIG. 3 are referred to as a close state D1, an intermediate state D2, and a separated state D3, respectively.

As shown in FIG. 3, when the top plate 16 is gradually moved away from the position close to the surface of the substrate W while the output of the heating plate 2 is kept constant, the temperature of the substrate W once rises. ,descend. That is, in the proximity state D1,
The heat of the substrate W is absorbed by the top plate 16, whereby the temperature of the substrate W relatively decreases. Further, in the intermediate state D2, the heat absorption by the top plate 16 decreases, and the temperature of the substrate W increases. Further, in the separated state D3, the capacity of the processing space 12 is increased, the heat retention is reduced, and the temperature of the substrate W is reduced again.

Based on such knowledge, in the substrate heat treatment apparatus according to the present embodiment, the substrate W
The distance between the table and the top plate 16 can be adjusted arbitrarily.

FIG. 4 is a sectional view showing an adjustment state of the top plate according to the inclination of the heating plate. FIG. 4 shows a method of adjusting the top plate 16 when the heating plate 2 is attached at an angle.

Usually, the heating plate 2 is fixed to the lower housing 1 so that the upper surface thereof is horizontal. Then, when the substrate W is placed on the spherical spacer 3, the substrate W is held in a horizontal posture. In this case, when it is considered that the influence of the temperature non-uniformity due to the invasion of the outside air into the processing space 12 at the time of loading and unloading the substrate or the temperature non-uniformity due to the bias of the natural heat radiation from the substrate W is small, 16 is preferably mounted horizontally and arranged parallel to the substrate W.

However, when the heating plate 2 is supported to be inclined with respect to the upper surface 1a of the lower housing 1,
The distance between the top plate 16 mounted horizontally with respect to the upper surface 1a and the substrate W held close above the heating plate 2 becomes uneven. For this reason, in the substrate W, temperature unevenness occurs between a portion where the top plate 16 is close and a portion where the top plate 16 is separated.

Therefore, the position adjusting member 19 is adjusted so that the substrate W on the heating plate 2 and the top plate 16 are parallel. Thereby, the distance between the substrate W and the top plate 16 becomes uniform over the entire surface of the substrate W, and the temperature distribution of the substrate W can be made uniform.

FIG. 5 is a sectional view showing a method of adjusting the top plate when the temperature in the processing space of the substrate heat treatment apparatus becomes uneven. In the processing space 12 of the substrate heat treatment apparatus, the substrate supply / discharge port 26 is opened at the time of loading / unloading of the substrate, and the outside air enters. It's easy to do. For this reason, each position adjusting bolt 1
9a is adjusted, and the top plate 1
3 in which the distance d1 between the substrate 6 and the substrate W is reduced.
At the opposite side of the substrate supply / discharge port 26, the top plate 16 is inclined and attached so as to be in the separated state D3 in FIG. This prevents the temperature of the substrate W from decreasing on the substrate supply / discharge port 26 side,
The temperature of the substrate W can be made uniform.

FIG. 6 is a sectional view of a main part of a substrate heat treatment apparatus according to a second embodiment of the present invention. In the substrate heat treatment apparatus of FIG. 6, the mounting structure of the top plate 16 is different from that of the first embodiment. The outer peripheral edge of the top plate 16 is fixed to the inner surface of the cover member 15. A position adjusting member 23 is disposed at the center of the upper surface of the top plate 16. The position adjusting member 23 includes a position adjusting bolt 23a, a fixing nut 23b, and a loose fitting nut 23.
c. The lower end of the position adjusting bolt 23a is rotatably engaged with the loose fitting nut 23c fixed to the upper surface of the top plate 16 so as not to be detached in the vertical direction, and the upper end penetrates the upper surface of the upper cover 15. It extends upward. Two fixing nuts 23b fixed to the upper and lower surfaces of the cover member 15 are screwed to the position adjusting bolt 23a.

Here, the position adjusting member 23 corresponds to the adjusting means and the connecting member of the present invention. Position adjustment bolt 23a
Is rotated so as to advance downward, the central portion of the top plate 16 is bent downward into a curved shape. Further, when the position adjusting bolt 23a is rotated to move upward, the central portion of the top plate 16 is bent upward in a curved shape. Thereby, the distance between the substrate W and the top plate 16 can be made different between the central portion and the outer peripheral portion of the substrate W.

When the diameter of the substrate W increases, the temperature of the outer peripheral portion of the substrate W tends to be lower than that of the central portion due to the difference between the amount of heat radiation from the central portion of the substrate W and the amount of heat radiation from the outer peripheral portion.
Therefore, the central portion of the top plate 16 is bent in the direction approaching the substrate W as shown in FIG. 6 to be in the proximity state D1 in FIG. 3, and the outer peripheral portion of the top plate 16 is in the intermediate state D2 in FIG. Thereby, the heat from the central portion of the substrate W is absorbed by the central portion of the top plate 16, and the temperature rise in the central portion of the substrate W is suppressed, whereby the temperature distribution of the substrate W can be made uniform.

In the substrate heat treatment apparatus shown in FIG.
A gas inlet (not shown) is provided at a position where it does not interfere with the position adjusting member 23 attached to the center of 6.

In the substrate heat treatment apparatus according to the present invention,
By arranging the position adjusting members 19 and 23 at arbitrary positions, the distance between the substrate W and the top plate 16 can be freely adjusted. The structure of the position adjusting members 19 and 23 is the same as that of the position adjusting bolts 19a and 19 shown in the first and second embodiments.
The structure is not limited to the nuts 23a, the nuts 19b, the fixing nuts 23b, and the loose fitting nuts 23c, and other structures capable of movably holding the top plate 16 with respect to the cover member 15 can be applied.

[Brief description of the drawings]

FIG. 1 is a side sectional view of a substrate heat treatment apparatus according to a first embodiment of the present invention.

FIG. 2 is a sectional view taken along line AA in FIG.

FIG. 3 is a diagram illustrating a relationship between a distance between a substrate and a top plate and a temperature of the substrate.

FIG. 4 is a cross-sectional view illustrating an adjustment state of a top plate according to an inclination of a heating plate.

FIG. 5 is a cross-sectional view illustrating a method of adjusting a top plate when temperature unevenness occurs in a processing space of the substrate heat treatment apparatus.

FIG. 6 is a sectional view of a main part of a substrate heat treatment apparatus according to a second embodiment of the present invention.

FIG. 7 is a schematic sectional view of a conventional substrate heat treatment apparatus.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Lower housing 2 Heating plate 12 Processing space 15 Cover member 16 Top plate 17 Hole 19, 23 Position adjusting member 19a, 23a Position adjusting bolt 19b Nut 23b Fixed nut 23c Free fit nut 25 Upper housing

Claims (6)

[Claims] 1. A substrate heat treatment apparatus for processing a substrate at a predetermined temperature, comprising: a base having a heat source and having a supporting portion for supporting a lower surface of the substrate; a lid member covering an upper part of the base; A top plate disposed inside the lid member so as to face the substrate supported by the support portion of the base; and each portion of the substrate supported by the support portion of the base and the top plate facing each other. An apparatus for heat-treating a substrate, comprising: adjusting means for adjusting an interval between portions. 2. The apparatus according to claim 1, wherein the adjusting unit includes a plurality of connecting members that connect the top plate and the lid member so that a distance between the top plate and the lid member can be adjusted. 2. The substrate heat treatment apparatus according to claim 1. 3. The substrate according to claim 2, wherein the plurality of connecting members are arranged so as to adjust the parallelism of the top plate with respect to the substrate supported by the support portion of the base. Heat treatment equipment. 4. The apparatus according to claim 2, wherein each of the plurality of connecting members includes a screw member. 5. An outer peripheral portion of the top plate is fixed to the lid member, and the adjusting means deflects the top plate into a curved shape so that a gap between a central portion of the top plate and a central portion of the lid member is provided. The substrate heat treatment apparatus according to claim 1, further comprising a connecting member that connects the top plate and the lid member so that the top plate can be adjusted. 6. The substrate heat treatment apparatus according to claim 5, wherein the connection member includes a screw member.