JPH0547652A - Substrate heater - Google Patents

Abstract

PURPOSE:To provide a substrate heater which can uniformly heat a substrate. CONSTITUTION:A semiconductor wafer 104 is supported in the vicinity of its end by three protrusion members 102 provided near the periphery of a heating base 101, and heat treated. In this case, the vicinity of the end of the wafer 104 is heated to a high temperature by the base through the members 102, but a part except it is uniformly heated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a substrate heating apparatus for performing heat treatment on a substrate such as a semiconductor wafer or a substrate for liquid crystal display (LCD).

[0002]

2. Description of the Related Art Conventionally, various heating devices have been used to perform heat treatment on substrates such as semiconductor wafers and LCD glass substrates. For example, in the photoresist processing step of the semiconductor manufacturing process, heat treatment is performed to dehydrate the water on the surface of the semiconductor wafer or to remove the solvent in the resist applied on the surface of the wafer. The heating method includes direct hot plate method, batch hot air heating method, microwave method, etc.
The direct hot plate method has become the mainstream due to the demands for efficiency improvement, cycle time reduction, reproducibility and uniformity improvement.

However, in the direct hot plate method, since the semiconductor wafer is brought into close contact with the hot plate and directly heated, the contact state between the hot plate and the semiconductor wafer greatly affects the uniformity of heat, and in general, the hot plate is made of aluminum. Since it is made of such a metal, there are problems such as heavy metal contamination and adhesion of particles to the back surface of the semiconductor wafer.

In order to eliminate such a problem, there is a proximity method in which a small gap is provided between the hot plate and the semiconductor wafer and the heat treatment is performed without directly adhering the semiconductor wafer to the hot plate. FIG. 7 shows a plan view of a conventional proximity-type substrate heating apparatus. Also,
8 is a cross-sectional view taken along the line BB of FIG. 7, and the same parts as those of FIG. 7 are denoted by the same reference numerals.

In FIGS. 7 and 8, three rectangular recesses 705 are provided in the vicinity of the center of the bottom surface of a heating table 701 having a heater built therein. Each of the recesses 705 is used for supporting a substrate. The ceramic ball 702 is the heating table 70.
1 is arranged so as to slightly project from the upper surface. In addition, in the vicinity of the central portion of the heating table 701, the semiconductor wafer 70
A support pin hole 703 for allowing a substrate support pin (not shown) to come in and out is provided in order to mount or remove the substrate 4 on or from the heating base 701.

In the substrate heating apparatus configured as described above, first, the substrate support pins are projected above the heating table 701 through the support pin holes 703, and then the semiconductor wafer 704 is placed on the substrate support pins. To do. Next, the semiconductor wafer 7
04 is placed on the ball 702, and heat treatment is performed. At this time, the sphere 702 slightly protrudes from the upper surface of the heating table 701, that is, the semiconductor wafer 704 and the heating table 701.
Since a minute gap exists between the semiconductor substrate 70 and
No particle contamination or the like occurs in No. 4, and heating can be performed efficiently.

[0007]

By the way, the integrated circuit (IC) formed on the semiconductor wafer 704 is usually formed on the entire surface of the semiconductor wafer 704 excluding the peripheral edge. In the substrate heating apparatus described above, the sphere 702 is arranged only near the center of the heating table 701. Since the semiconductor wafer 704 is in contact with the heating table 701 via the sphere 702, the vicinity of the central portion is heated to a higher temperature than other portions. Therefore, the semiconductor wafer 70
There was a problem that the in-plane temperature distribution of No. 4 became non-uniform. In particular, in the case of post-baking for hardening the resist pattern, there is a problem that the thickness and shape of the resist pattern are partially changed if the temperature of the portion corresponding to the resist pattern becomes too high.

Further, since the ball 702 is arranged in the recess 705 without being fixed, the ball 702 is recessed when cleaning the heating table 701 or removing the semiconductor wafer 704.
The semiconductor wafer 704 may be pulled out of or lifted up from the heating table 701 in this state.
There is a problem that the heating becomes uneven because it is inclined with respect to the upper surface of the.

The present invention focuses on the fact that in a substrate such as a semiconductor wafer or an LCD that requires heat treatment, a main part such as a resist pattern which should be uniformly heated is provided in a part other than the peripheral edge. The first aspect of the present invention has an object to provide a substrate heating device capable of heating a main part of a substrate uniformly to substantially uniformly heat the substrate. The second invention is
It is an object of the present invention to provide a substrate heating device capable of uniformly heating even a large substrate. A third aspect of the present invention has an object to provide a substrate heating device capable of uniform heating by preventing the substrate from tilting.

[0010]

The invention according to claim 1 is
The heating table includes a heating table and a plurality of projecting members projecting from the heating table to support the substrate to be heated near its end. Further, the invention according to claim 2 is, in addition to the substrate heating apparatus according to claim 1, provided with a protrusion member for supporting the substrate at its central portion.

Furthermore, the invention according to claim 3 is the same as claim 1.
Alternatively, in addition to the substrate heating apparatus according to the second aspect, the protruding member is fixed to the heating table.

[0012]

The substrate is heated substantially uniformly by supporting the substrate in the vicinity of its ends by using the plurality of projecting members. Also, if the central portion is also supported by the projecting member, the gap between the substrate and the heating table is evenly maintained and the entire substrate is evenly heated even in the case of a relatively large substrate.

Further, if each protruding member is fixed to the heating table, the protruding member will not be pulled out or lifted up.
The substrate is heated uniformly without tilting.

[0014]

EXAMPLE The substrate heating apparatus of this example described below is used in various substrate processing steps. For example, in a semiconductor manufacturing process, in an adhesion process, which is a process for improving the adhesion between a semiconductor wafer and a resist, a substrate heating device is installed in a processing chamber, and a semiconductor wafer before resist coating is heated by the substrate heating device. It is placed on the table top and heated, and the HM
A gas such as DS (hexamethyldisilazane) is supplied. In addition, various steps that require heat treatment of the substrate, such as a pre-baking process for evaporating and removing a solvent such as thinner after applying a resist to a semiconductor wafer or a post-baking process for increasing the hardness of the resist after development. Used in.

The embodiments of the present invention will be described below. FIG. 1 is a plan view showing an embodiment of the present invention and shows an example of a proximity type substrate heating apparatus which is a kind of substrate heating apparatus for semiconductor wafers. 2 is a sectional view taken along the line AA, and the same parts as those in FIG. 1 are denoted by the same reference numerals. 1 and 2, the circular heating table 10
1 has a built-in heating member (not shown) capable of adjusting a heating temperature such as an electric heater. The heating table 101
The heating temperature and heating time can be variously set according to the purpose of the treatment. For example, in the case of adhesion treatment, heating is performed at about 80 to 100 ° C. for about 30 seconds.
For pre-baking, 1 at about 120-150 ℃
Heat for 1 minute. In the case of post-baking, heating is performed at about 120 to 150 ° C. for about 1 minute. In the case of cooling for cooling, it is controlled to room temperature (for example, 23 ° C.). On the peripheral portion of the heating table 101, three projecting members 102 for supporting the substrate are provided. Each projection member 102 may have a structure in which a recess is provided in the heating table 101 as described with reference to FIGS. 6 and 7, and a sphere formed of ceramic or the like is disposed in the recess without being fixed. The structure may be fixed to the heating table 101 as described later. Each protruding member 102 is a heating table 101.
About 0.1 to 0.3 mm above the upper surface of the.

The semiconductor wafer 1 is mounted on the heating table 101.
A support pin hole 103 for allowing a substrate support pin (not shown) to come in and out is provided for use when placing 04 on the heating table 101 or removing it from the heating table 101. The operation of the substrate heating apparatus configured as above will be described below. A semiconductor wafer 104 transferred from a processing device such as a sender that sends out a semiconductor wafer before processing or a coater that applies photoresist to the semiconductor wafer is first transferred through a support pin hole 103 by a transfer mechanism (not shown). It is placed on the three substrate support pins protruding above the heating table 101.

Next, each substrate support pin is housed in the lower part of the heating table 101, and the semiconductor wafer 104 is placed on the protruding member 102. In this state, the semiconductor wafer 104 is heated by the electric heater built in the heating table. The heating temperature and the heating time are variously set depending on the type of processing as described above. The protruding member 102 is
Since the semiconductor substrate 604 protrudes from the upper surface of the heating table 101 by about 0.1 to 0.3 mm, that is, there is a gap of about 0.1 to 0.3 mm between the semiconductor wafer 104 and the heating table 101, the semiconductor substrate 604 has particles. Contamination does not occur, and efficient heating is possible.

At this time, each protruding member 102 is attached to the heating table 10
1 is arranged in the vicinity of the peripheral portion of the semiconductor wafer 1.
04, the vicinity of its end is supported by each protruding member 102. Therefore, the peripheral portion of the protruding member 102 near the edge of the semiconductor wafer 104 is heated to a higher temperature than the other portions, but since the IC is provided inside the edge of the semiconductor wafer 104, the IC The provided portion is heated uniformly by the radiation heat from the heating table, etc., and the semiconductor wafer 104 can be heated substantially uniformly.

The semiconductor wafer 104 which has been heat-treated as described above is heated by the substrate support pins protruding from the support pin holes 103 to the upper part of the heating table 101.
It is removed from 1 and transported to the next step. FIG. 3 is a diagram showing a second embodiment of the present invention and is a plan view corresponding to FIG. The same parts as those in FIG. 1 are designated by the same reference numerals.

In the embodiment of FIG. 3, in addition to the embodiment of FIG. 1, a protruding member 301 is provided at the center of the heating table 101. The tip of the protrusion member 301, that is, the contact portion with the semiconductor wafer 104 is preferably as thin as possible in terms of particle adhesion and heating uniformity. When the diameter of the semiconductor wafer 104 becomes large, for example, about 8 inches, when only the vicinity of the end portion is supported by the projecting member 102, the semiconductor wafer 104 bends and its central portion contacts the heating table 101, and particles etc. May be contaminated by. However, the protruding member 30 provided in the central portion
By supporting the semiconductor wafer by means of 1, it becomes possible to prevent the semiconductor wafer 104 from bending, and the entire semiconductor wafer 104 is heated more uniformly.

4 (a) and 4 (b) are a partial plan view and a partial sectional view showing the structures of the above-mentioned projecting members 102 and 301, and the same parts as those in FIG. 1 are designated by the same reference numerals.
In FIGS. 4A and 4B, the projecting member 401 having a circular plan view is housed in the recess 403 provided in the heating table 101, and the screw portion 40 provided on the side wall of the recess 403.
It is fixed by a nut 402 that is screwed with the screw 4. The protrusion 401 protrudes from the upper surface of the heating table 101 by about 0.1 to 0.3 mm. The semiconductor wafer 104 is placed on the protrusion 403. In addition, instead of screwing the nut 402, the protrusion member 401 may be fixed by press-fitting and attaching a resinous ring-shaped member made of a material such as PTFE into the recess.

As described above, the protruding member 401 is attached to the heating table 10.
By fixing it to 1, the protruding member 401 can be pulled out,
Therefore, the semiconductor wafer 104 can be prevented from tilting with respect to the upper surface of the heating table 101. In addition, since no recess is provided to store the balls, the problem that dust and the like will be stored does not occur. 5 (a) and 5 (b) are a partial plan view and a partial cross-sectional view showing another embodiment of the above-mentioned protrusion member 102, respectively.
The same reference numerals are given to the same portions as.

In FIGS. 5A and 5B, the sheet 501, which is a protruding member, is fixed on the heating table 101 by the SUS screw member 503 via the Teflon washer 502. As the sheet 501, a material that has heat resistance, does not easily deform, and does not generate dust, such as ceramics, is used. The sheet 501 has a thickness of about 0.1 to 0.3 mm, and the semiconductor wafer 104 is placed on the sheet 501.

As described above, the sheet 501 is placed on the heating table 101.
By fixing the sheet 501 to the sheet 501, the sheet 501 does not come off or float up, so that the semiconductor wafer 104 can be prevented from tilting. Further, while it is extremely difficult to manufacture and embed a sphere with high dimensional accuracy, the sheet 501 can be easily formed with various thicknesses and can be changed. Therefore, by changing the thickness of the sheet 501, it is possible to easily change various gaps between the heating table 101 and the semiconductor wafer 104. Furthermore, since no recess is provided for storing the balls, the problem of accumulating dust and the like does not occur.

6 (a) and 6 (b) are a partial plan view and a partial cross-sectional view showing another structure of the above-mentioned protruding member 102, respectively. The same parts as those in FIG. 1 are designated by the same reference numerals. There is. In FIGS. 6A and 6B, a ceramic protrusion member 601 which is a protrusion member includes a seat portion 603 and a fixing portion 604.
It consists of The seat portion 603 has a thickness of about 0.1 to 0.3 mm, and the fixing portion 604 and the seat portion 60 are provided.
An inclined portion 605 is formed at the connecting portion of No. 3. The protruding member 601 is fixed to the heating table 101 by a screw member 602. The semiconductor wafer 104 is placed on the sheet portion 603.

As described above, the protruding member 601 is attached to the heating table 10.
By fixing it to 1, the protruding member 601 can be pulled out,
Therefore, the semiconductor wafer 104 can be prevented from tilting. In addition, the inclined portion 605 formed on the protruding member 601 is provided with the semiconductor wafer 1
04 has a function of guiding. Therefore, even when the position of the semiconductor wafer is slightly displaced when the semiconductor wafer 104 is placed on the heating table 101, the semiconductor wafer 104
Slides along the inclined portion 3 and is placed at the center of each protruding member 601, that is, the center of the heating table.

As described above, according to each of the above-described embodiments, the substrate can be heated substantially uniformly.
Further, since the substrate can be prevented from tilting, it is possible to uniformly heat the substrate. Furthermore, by providing the heating table 101 with a structure that does not have a recess for accommodating balls,
Since the portion of the heating table facing the semiconductor wafer 104 is flat, there are various effects such as uniform heating.

The above-described embodiment is for a substrate heating apparatus for a semiconductor wafer, but it can also be used for various substrates such as LCD substrates that require heat treatment. Further, although the example of the circular substrate has been described, the present invention can also be applied to the case of a polygonal substrate such as a triangle or a square. Further, although the sheet is used as the protruding member in the embodiment of FIG. 5, it may be a wire-shaped member.

[0029]

According to the first aspect of the present invention, the substrate can be heated substantially uniformly. According to the second aspect of the present invention, even if the substrate is large, no bending occurs, and uniform heating is possible. Further, claim 3
According to the described invention, it is possible to prevent the substrate from tilting, so that uniform heating is possible.

[Brief description of drawings]

FIG. 1 is a plan view showing an embodiment of the present invention.

2 is a sectional view taken along line AA of the embodiment shown in FIG.

FIG. 3 is a plan view showing another embodiment of the present invention.

4 (a) and 4 (b) are a partial plan view and a partial sectional view, respectively, showing an embodiment of a protrusion member used in the present invention.

5 (a) and 5 (b) are a partial plan view and a partial sectional view, respectively, showing another embodiment of the protrusion member used in the present invention.

6 (a) and 6 (b) are a partial plan view and a partial sectional view, respectively, showing another embodiment of the protrusion member used in the present invention.

FIG. 7 is a plan view of a conventional substrate heating device.

8 is a cross-sectional view taken along line BB of the substrate heating device shown in FIG.

[Explanation of symbols]

 101 ... Heating table 102, 301, 401, 601 ... Projection member 103 ... Support pin hole 104 ... Semiconductor wafer as substrate 501 ... Sheet as projection member

Claims (3)

[Claims] 1. A substrate heating apparatus comprising: a heating table; and a plurality of projecting members projecting from the heating table for supporting a substrate to be heated near an end thereof. 2. The substrate heating apparatus according to claim 1, further comprising a protrusion member for supporting the substrate at its central portion. 3. The substrate heating apparatus according to claim 1, wherein the protrusion member is fixed to the heating table.