JPH098049A - Board heating device - Google Patents

Abstract

PURPOSE: To provide a board heating device wherein irregularity is hard to generate in heat treatment of a board when carrying a board into a board heating device. CONSTITUTION: An untreated wafer W is carried into a housing 20 and is mounted on a hot plate 40. Then, a hot plate cover 60 descends and the wafer W mounted on the hot plate 40 is thermally treated inside a half-closed space formed of the hot plate 40 and the hot plate cover 60. When the untreated wafer W is carried into the housing 20, a heater wire 66 is energized for heating a delivery position side of the hot plate cover 60. Therefore, even if high temperature atmosphere below the hot plate cover 60 is pushed into the inner part by the air outside entered from a shutter 20a in a delivery position of the wafer W and a temperature of an upper plate 62 of the hot plate cover 60 lowers for a time, temperature irregularity of the upper plate 62 caused by such temperature lowering is compensated rapidly.

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 heating semiconductor wafers and glass substrates for liquid crystal displays.

[0002]

2. Description of the Related Art A substrate processing apparatus for performing various processes such as resist coating, heat treatment, and cooling treatment on a semiconductor wafer in a desired procedure is widely known.

FIG. 4 is a view for explaining the general structure of a bake unit which is a substrate heating device incorporated in a part of this type of substrate processing apparatus. As shown in the figure, inside the housing 2 that covers the outside, a hot plate 4 for heat-treating the wafer and a semi-enclosed space that descends onto the hot plate 4 during the heat treatment of the wafer to form a semi-enclosed space. And a hot plate cover 6 for accommodating the wafer.

When the wafer is loaded, the shutter 2a provided on the housing 2 is opened to raise the hot plate cover 6. When the processed wafer exists inside, the processed wafer is first carried out of the housing 2 by using the transfer robot. Then, an unprocessed wafer is loaded into the housing 2 and placed on the hot plate 4. After that, the hot plate cover 6 is lowered to hold the wafer placed on the hot plate 4 in the semi-enclosed space formed by the hot plate 4 and the hot plate cover 6, and the wafer in this space is desired to have a desired size. Heat treatment is performed under temperature and time conditions.

[0005]

However, in the apparatus shown in FIG. 4, the outside air O entering from the shutter 2a at the time of carrying in the wafer.
Due to A, it may be difficult to uniformly heat the wafer.

That is, when the wafer is loaded, the shutter 2a
Is opened and the hot plate cover 6 is moved to the raised position, the hot plate cover 6 is moved from the shutter 2a side.
Outside air OA enters below. At this time, the hot plate 4
Since the weak exhaust EA is performed downward around the area A, the high temperature atmosphere HA under the hot plate cover 6 is pushed inward due to the flow of the outside air OA and the exhaust EA. As a result, the temperatures of the inner surface of the hot plate 4 and the surface of the hot plate cover 6 relatively drop on the delivery position side where the shutter 2a is located, and the temperature on the inner surface of the hot plate 4 and the surface of the hot plate cover 6 increases from the delivery position side to the back side. A gradient occurs. Since such a temperature gradient causes temperature nonuniformity in the wafer surface immediately after the start of the heat treatment,
As a result, the heat treatment of the wafer may become non-uniform within the surface.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a substrate heating apparatus in which heat treatment of a substrate is less likely to occur even if outside air flows into the apparatus from the delivery position when the substrate is carried into the substrate heating apparatus. And

[0008]

In order to solve the above problems, a substrate heating apparatus according to a first aspect of the present invention is a substrate heating apparatus for supporting a substrate on a plate and performing a predetermined heat treatment on the substrate, a cover for covering the plate. Among them, at least the heating means for heating the cover is provided on the delivery position side where the substrate is loaded and unloaded.

According to a second aspect of the present invention, there is provided a substrate heating apparatus, wherein the heating means is a heating element disposed on the cover, and the heating element is a delivery side portion of the heating element and is deep in the heating element. It is characterized in that it is arranged more densely than the side portions.

[0010]

In the substrate heating apparatus according to the first aspect of the present invention, since the heating means for heating the cover is provided on at least the delivery position side where the substrate is carried in and out of the cover that covers the plate, the substrate is carried in. Also, even if the high temperature atmosphere under the cover is pushed into the back of the cover due to the outside air entering from the delivery position at the time of unloading, the temperature of the cover can be compensated for the temperature drop on the delivery position side of the cover by the operation of the heating means. it can. Therefore, the amount of heat received by the substrate can be equalized within the surface from the beginning of the heat treatment, and the heat treatment of the substrate can be made uniform.

Further, in the substrate heating apparatus according to the present invention, the heating means is a heating element disposed on the cover, and the heating element is a delivery side portion of the heating element and a back side portion of the heating element. Since they are arranged more densely, it is possible to effectively heat the delivery-side end of the cover, where the temperature is the lowest due to the entering outside air.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a diagram for explaining the structure of a baking unit which is an embodiment of the substrate heating apparatus according to the present invention.

As shown in the drawing, a hot plate 40 for heating the wafer W at a desired temperature is provided inside the housing 20 constituting the outside of the bake unit 10, and a hot plate 40 is placed on the hot plate 40 during the heat treatment of the wafer W. A hot plate cover 60 is provided that descends to form a semi-enclosed space for keeping heat.

A shutter 20a is provided on the side surface of the housing 20. This shutter 20a is used for the unprocessed wafer W.
Is opened when the wafer W is carried into the housing 20 for heat treatment or when the processed wafer W is carried out of the housing 20, and is closed during the heat treatment of the wafer W.

The hot plate 40 includes a lifter pin 42 for receiving a wafer W loaded from the outside of the housing 20 via a shutter 20a by three-point support, and a proxy for receiving the wafer W from the lifter pin 42 and supporting it on the hot plate 40. And a ball 44 for a miti gap. Each lifter pin 42 can be moved up and down by an actuator (not shown), and by operating these lifters in synchronization, the wafer W can be held horizontally and moved up and down. The proximity gap ball 44 is fixed on the hot plate 40, and is lifted by the lifter pin 42.
The wafer W, which has descended with the lowering, is supported on the hot plate 40 so as to be parallel to the surface of the hot plate 40.

The hot plate cover 60 includes an upper plate portion 62 that covers the wafer W from above, and a skirt-shaped side plate portion 64 that extends downward from the peripheral edge of the upper plate portion 62. The hot plate cover 60 can be moved up and down by an elevating mechanism (not shown), and when the shutter 20a is opened during loading and unloading of the wafer W, the hot plate cover 60 is raised to the raised position shown in FIG. When the shutter 20a is closed during the processing of the wafer W, the shutter 20a is lowered to form a semi-enclosed space on the hot plate 40.

The upper plate portion 62 of the hot plate cover 60 is provided with a heating portion 66 for heating half of the hot plate cover 62 on the delivery position side near the shutter 20a. Such a heating unit 66 is provided because the shutter 2 is used for loading and unloading the wafer W.
Even when the high temperature atmosphere under the hot plate cover 60 is pushed into the back of the hot plate cover 60 by the outside air that has entered from the 0a side, the temperature of half of the hot plate cover 60 on the delivery position side is raised to raise the upper plate. This is to prevent the temperature unevenness from occurring in the portion 62.

FIG. 2 is a plan view showing the arrangement of the heater wire 68 which is a heating element incorporated in the heating portion 66 formed on the hot plate cover 60. As is clear from the figure, the heater wire 68 is the upper plate portion 6 of the heating portion 66.
2 is arranged relatively densely in the delivery side portion 66a close to the delivery side end 62a, and relatively coarsely arranged in the back side portion 66b of the heating portion 66 near the back side end 62b of the upper plate portion 62. There is. The arrangement density of the heater wires 68 is changed in this manner in order to more accurately compensate for the temperature non-uniformity generated in the upper plate portion 62 of the hot plate cover 60 due to the outside air entering from the shutter 20a side. That is, the heater wire 68 is the delivery side portion 66a and the back side portion 66b.
Since the hot plate cover 60 is arranged more densely than the above, it is possible to effectively heat the end and the vicinity of the delivery position side of the hot plate cover 60 where the temperature of the hot plate cover 60 is most lowered by the entering outside air.

The operation of the bake unit shown in FIG. 1 will be described below. First, the shutter 20a provided in the housing 20 for loading the wafer W is opened to open the hot plate cover 60.
To rise. When the processed wafer W exists inside, the processed wafer W is transferred to the hand (not shown) of the transfer robot in advance using the lifter pins 42 and carried out of the housing 20. Next, the unprocessed wafer W is loaded into the housing 20 and placed on the hot plate 40. After that, lower the hot plate cover 60,
The unprocessed wafer W placed on the hot plate 40 is heat-treated for a desired time in a semi-enclosed space formed by the hot plate 40 and the hot plate cover 60.

When the unprocessed wafer W is loaded into the housing 20, the heater wire 68 is energized to heat the delivery position side of the hot plate cover 60. As a result, the high temperature atmosphere under the hot plate cover 60 is pushed inward by the outside air that has entered from the shutter 20a on the delivery position side of the wafer W, and a temporary temperature drop occurs on the delivery position side of the upper plate 62 of the hot plate cover 60. Even if it occurs, the temperature non-uniformity of the upper plate 62 due to the temperature decrease is quickly compensated.

FIG. 3 is a graph for explaining how the heater wire 68 prevents the temperature non-uniformity that occurs in the upper plate 62 of the hot plate cover 60. The vertical axis represents temperature, and the horizontal axis represents time elapsed after closing the shutter 20a. One solid line b in the graph indicates the temperature change in the central region of the upper plate 62 of the hot plate cover 60. Further, the other solid line a in the graph indicates a temperature change in the vicinity of the delivery side end 62a of the upper plate 62, assuming that the heater wire 68 is not energized after the shutter 20a is opened. As is apparent from the figure, the time t2 when the temperature near the delivery side end 62a is saturated becomes considerably later than the time t1 when the temperature in the central region is saturated.

On the other hand, the dotted line c in the graph indicates the shutter 20.
When the heater wire 68 is energized after opening a, the upper plate 62
Of these, the temperature change in the vicinity of the delivery side end 62a is shown. As is clear from the figure, the time t2 ′ when the temperature near the delivery side end 62a is saturated is almost equal to the time t1 when the temperature near the back side end 62b is saturated. Therefore, the amount of heat the wafer W receives from the surrounding hot plate 40 and the hot plate cover 60 can be equalized from the beginning of the heat treatment in each part of the wafer W plane to make the heat treatment of the wafer W uniform. it can.

Although the present invention has been described with reference to the embodiments, the present invention is not limited to the above embodiments.
For example, in the above-described embodiment, the heating unit 66 is arranged in about half of the upper plate portion 62 of the hot plate cover 60. However, the arrangement position of the heating unit 66 is set at the heat treatment condition or when the wafer W is delivered. It can be changed as appropriate according to the operating conditions and the like.
However, the shutter 20 of the hot plate cover 62
It is necessary that at least the heating unit 66 is provided in the portion on the delivery position side near a.

Further, the heater wire 6 incorporated in the heating section 66.
The arrangement and shape of 8 are not limited to those in the above embodiment. However, since it is considered that the temperature of the hot plate cover 62 closer to the shutter 20a tends to decrease, the arrangement density of the heater wires 68 considered to generate the same amount of heat per unit length is the delivery side portion 66a. Therefore, it is necessary to make it relatively dense.

Further, in the above embodiment, the timing of energizing the heater wire 68 is synchronized with the timing of opening the shutter 20a, but it is also possible to use a temperature sensor incorporated in the hot plate cover 62. In this case, when the output of the temperature sensor indicates a temperature below a certain threshold value, it is considered that the heater wire 68 is energized,
Furthermore, it is also possible to adjust the power supplied to the heater wire 68 according to the amount of deviation from the output threshold value.

In the above embodiment, the hot plate cover 62 is moved up and down to carry the wafer W in and out. However, the hot plate cover 62 is not moved up and down and a shutter is provided on this side. The wafer W can be loaded and unloaded through this shutter.

[0027]

As described above, according to the substrate heating apparatus of the first aspect, the heating for heating the cover at least on the delivery position side where the substrate is carried in and out of the cover that covers the plate. Since a means is provided, even if the high temperature atmosphere under the cover is pushed into the back of the cover by the outside air that has entered from the delivery position when the substrate is loaded and unloaded, and the temperature of the cover becomes uneven, the cover is delivered by the operation of the heating means. Since the temperature decrease on the position side can be compensated, the heat amount received by the substrate can be made equal within the plane from the beginning of the heat treatment, and the heat treatment of the substrate can be made uniform.

According to the substrate heating device of the second aspect,
Since the heating means is a heating element arranged on the cover, and the heating element is arranged closer to the delivery side portion of the heating element than to the back side portion of the heating element, the outside air that has entered Thus, the delivery-side end of the cover where the temperature drops the most can be effectively heated, and the heat treatment of the substrate can be easily and uniformly performed.

[Brief description of drawings]

FIG. 1 is a side view illustrating a sectional structure of a heat treatment apparatus according to an embodiment of the present invention.

FIG. 2 is a plan view illustrating a main part of the apparatus shown in FIG.

FIG. 3 is a diagram illustrating the operation of the apparatus of FIG.

FIG. 4 is a diagram illustrating a structure of a conventional device.

[Explanation of symbols]

 20 Housing 20a Shutter 40 Hot Plate 42 Lifter Pin 44 Proximity Gap Ball 60 Hot Plate Cover 62 Upper Plate Part 64 Side Plate Part 66 Heating Part W Wafer

Claims (2)

[Claims] 1. A substrate heating apparatus for supporting a substrate on a plate and performing a predetermined heat treatment on the substrate, comprising: a cover for covering the plate, at least on a delivery position side where the substrate is loaded and unloaded. A substrate heating device comprising a heating means for heating the cover. 2. The heating means is a heating element disposed on the cover, and the heating element is denser in a delivery side portion of the heating element than in a back side portion of the heating element. The substrate heating apparatus according to claim 1, wherein the substrate heating apparatus is provided.