JPH07153678A - Substrate cooling apparatus - Google Patents

Abstract

PURPOSE:To uniformly cool a substrate, to be treated, which has been heated and to obtain a pattern whose uniformity inside a face is good by a method wherein a substrate mounting means, a gas nozzle with a shock-absorbing plate and a flow-regulating means which is arranged and installed in parallel with the substrate to be treated are installed. CONSTITUTION:A shock-absorbing plate 5 and a flow-regulating plate 7 are fixed and bonded to the tip of a nozzle 4. The shock-absorbing plate 5 is fixed and bonded to the nozzle 4 by a screw 6 which is divided into three, and a gas can be ventilated freely. A photomask 1 is mounted on pins 3a to 3d, an air cylinder 9 is then actuated, the pins 3a to 3d are lowered, a cool plate 2 is brought close to a photomask 1, and the nozzle 4 to which the flow- regulating plate 7 has been fixed and bonded is brought close to the photomask 1 so as to be parallel. Then, clean nitrogen gas which is introduced from an input port 10 in the nozzle 4 hits the shock-absorbing plate 5, and it is diffused to the outer circumference. In addition, a gap between the photomask 1 and the flow-regulating plate 7 is set at 10mm or lower. In addition, the flow rate of the nitrogen gas is set at 5 to 30 l/min.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a photomask for semiconductors and liquid crystal panels or a cooling device for cooling substrates such as semiconductors and liquid crystal panels.

[0002]

2. Description of the Related Art A semiconductor photomask will be described as an example. The latest semiconductor photomask is formed by sputtering a chromium film of about 1000 angstrom on a glass substrate of 152 mm square and a thickness of 6.3 mm, applying a resist on it, drawing a pattern with an electron beam drawing device, and then developing the resist. Then, the chrome film is etched and the resist is stripped off to complete the process.

Chemically amplified resists have been developed and put into practical use as resists which are highly dry-etching resistant and highly accurate resist patterns can be obtained as the degree of integration of LSIs increases and patterns become finer. A typical product is SAL601 from Shipley.

After the chemically amplified resist is drawn with an electron beam,
The resist sensitivity is amplified by baking at about 110 ° C., but the final resist sensitivity is determined by the total amount of heat from heating to cooling. Therefore, in order to obtain a resist pattern having good in-plane uniformity and sensitivity, it is indispensable not only to uniformly heat the photomask without a temperature difference but also to uniformly cool the photomask.

There are two conventional methods for cooling a heated photomask. The first is a natural cooling method in which a photomask is left in the space to cool. The second is a cool plate method in which a photomask is placed on a cooling plate and cooled. When a glass substrate with a thickness of 6.3 mm is cooled by the above-mentioned conventional method, cooling proceeds from the outer periphery of the photomask, and the temperature difference between the central portion and the central portion reaches 10 to 20 ° C., which causes a large difference in resist sensitivity and high dimensional accuracy. Is not obtained.

Further, there is a defect that the time for cooling the photomask at 110 ° C. to 30 ° C. is about 25 minutes by the natural cooling method and about 15 minutes by the cool plate method, which is extremely long.

[0007]

SUMMARY OF THE INVENTION An object of the present invention is to provide a substrate cooling device capable of uniformly cooling a heated substrate and obtaining a pattern dimension with good in-plane uniformity.

Another object of the present invention is to provide a substrate cooling apparatus which has a high cooling rate and a short substrate heat treatment time.

[0009]

The present invention is characterized in that it comprises a substrate mounting means, a gas nozzle provided with a buffer plate, and a current plate arranged in parallel with the substrate to be processed.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings. Figure 1
a is a front view of the substrate cooling device of the present invention, and FIG. 1b is a plan view.

The photomask 1 is placed on the pins 3a to 3d of the cool plate 2 by a transport mechanism (not shown).
A buffer plate 5 and a current plate 7 are fixed to the tip of the nozzle 4. The buffer plate 5 is fixed to the nozzle 4 with a screw 6 divided into three, and the gas can flow freely. After the photomask 1 is placed on the pins 3a to 3d, the air cylinder 9 is operated to lower the pins 3a to 3d and bring the gap between the cool plate 2 and the photomask 1 close to about 0.1 mm.
The nozzle 4 to which the current plate 7 is fixed is brought close to the photomask 1 in parallel by a mechanism (not shown).

The clean nitrogen gas introduced from the input port 10 of the nozzle 4 hits the buffer plate 5 and diffuses to the outer periphery. Further, the flow straightening plate 7 and the photomask 1 serve as a guide to form a uniform flow to cool the photomask.

By making the size of the current plate 7 larger than that of the photomask 1, the flow of nitrogen gas on the upper surface of the photomask 1 can be made uniform, so that cooling can be made uniform. If the gap between the photomask 1 and the current plate 7 is set to 20 mm or more, a turbulent flow of nitrogen gas is generated and cooling is irregular because the nitrogen gas does not flow evenly to the outer periphery.
It is necessary to do the following.

If the flow rate of nitrogen gas is small, the cooling is the same as in the conventional cool plate method, and the cooling of the central portion is delayed. On the contrary, if the flow rate is too high, the cooling of the central portion becomes faster. As a result of the investigation, by setting the flow rate to 5 L / min to 30 L / min, it was possible to uniformly cool various substrates in the range of 2 to 5 ° C. Further, the time for cooling the photomask at 110 ° C. to 30 ° C. is about 5 minutes, which is 1/3 to 1/5 of the conventional cooling method.

In the above description, the pin 3a is used as the substrate mounting means.
Although the case of using ~ 3d has been described, the cool plate 2 may be removed and placed on the pins 3a to 3d to be a method close to conventional natural cooling, or the photomask 1 may be placed directly on the crew plate 2. It is clear that the present invention can also be realized by arranging them.

In the above description, the case where the flow straightening plate 7 is fixed to the nozzle 4 has been described, but the present invention is not limited to this, and even if the flow straightening plate 7 and the nozzle 4 are separated, the same is true. realizable.

In the above description, a photomask is used as an example, but the same can be realized with a semiconductor substrate or a liquid crystal panel substrate.

[0018]

As described above, the present invention has the following effects. By uniforming the cooling rates of the central portion and the outer peripheral portion of the substrate to reduce the difference in sensitivity of the resist, a uniform and highly accurate pattern can be obtained. Further, high productivity can be obtained by cooling in a short time.

[Brief description of drawings]

FIG. 1a is a front view of a substrate cooling device of the present invention.

FIG. 1b is a plan view of the substrate cooling device of the present invention.

[Explanation of symbols]

1 ... Photomask, 2 ... Cool plate, 3a-3d ... Pin, 4 ... Nozzle, 5 ... Buffer plate, 6 ... Screw, 7 ... Rectifier plate,
9 ... Air cylinder, 10 ... Input port.

Claims (4)

[Claims] 1. A substrate cooling apparatus comprising: a substrate mounting means; a gas nozzle provided with a buffer plate; and a current plate arranged in parallel with a substrate to be processed. 2. The substrate cooling device according to claim 1, wherein the size of the current plate is not smaller than that of the substrate to be processed. 3. The substrate cooling device according to claim 1, wherein the distance between the current plate and the upper surface of the substrate to be processed is 10 mm or less. 4. The flow rate discharged from the gas nozzle is 5 to 5.
The substrate cooling device according to claim 1, wherein the cooling rate is 30 L / min.