JPS59154444A - Method for coating resist - Google Patents

Abstract

PURPOSE:To make the thickness of a coated film uniform by regulating the speed of revolution of a turntable in the early and last stages of coating when a resist is coated on the principal surface of a substrate for a videodisc or the like while turning the substrate around an axis perpendicular to the principal surface of the substrate. CONSTITUTION:A substrate W is fixed on a turntable 1, the turntable 1 is rotated, and while releasing a resist from a nozzle 4, the nozzle 4 is moved in the direction of an arrow 5 to stick the resist to the principal surface Wa of the substrate W. In the early stage of coating, the turntable 1 is rotated at a high speed for a fixed time, and then the speed is reduced. The speed is further reduced, and in the last stage of coating, the turntable 1 is rotated at a low speed. Thus, the thickness of a resist film coated on the surface Wa of the substrate W is made uniform. The reason that the film is made uniform is that the action of centrifugal force is eliminated by the interaction between a change in the amount of a solvent remaining in the resist with the lapse of time and said change in the speed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to an improvement in a resist coating method for coating a substrate with a resist in a final step of manufacturing a video desk or the like.

[Technical background of the invention and its problems]

For example, the manufacturing of video desks involves the process of applying resist to a glass substrate. This step is carried out by attaching the glass substrate to a turntable and rotating it, and ejecting cysts from a nozzle onto the main surface of the rotating glass substrate. Then, the rotation is performed at a constant speed corresponding to the film thickness so that the resist becomes a coating film of a desired thickness, and the excess resist is removed by centrifugal force, and at the same time, the solvent evaporates, completing the coating.

However, since the magnitude of centrifugal force varies depending on the distance from the center of rotation, this conventional method has the disadvantage that the film thickness is not constant, resulting in a decrease in the quality of the video desk.

[Purpose of the invention]

An object of the present invention is to provide a coating method that makes the thickness of a resist coated on a substrate constant.

[Summary of the invention]

After a resist is attached to a substrate, the substrate is subjected to high-speed rotation at least in the initial stage of coating, decelerated rotation in the middle of coating, and low-speed rotation in the final stage of coating. is made to be constant.

[Embodiments of the invention]

Hereinafter, the present invention will be described based on embodiments with reference to the drawings.

As shown in FIG. 1, the resist coating apparatus used in the method of the present invention is equipped with a turntable (1) that holds a glass substrate (W-) by suction. The turntable (1) can be turned at any time and at any speed by means of a drive unit and a control device (not shown). A groove (3) communicating with a vacuum passage (2) connected to a vacuum source (not shown) is formed on the table surface of the turntable (1).
) on the turntable +1. ) is now available for identification. A nozzle (4) for depositing resist onto the main surface (Wa) of the substrate (W) is housed facing the turntable (1) via the substrate (W).

This nozzle 7l-(4) is provided with an envelope (ra) for collecting the resist scattered from near the center of the substrate shown by the arrow (5).

Next, the coating method will be described.

First, the substrate (W) is fixed to the turntable (1) by adsorption under reduced pressure. Then, while the turntable (1) is fully rotated and the nozzle (4) is moved in the direction of the arrow (5) while discharging the resist from the nozzle (4), the main surface (Wa) of the substrate (VV) is removed. Attach resist to. 1. As shown in Figure 2A, the turntable (1) is rotated at a high speed for t1 hours, then decelerated to N2 at a constant acceleration for 12 hours, and then continued for 1 s. The resist is rotated with N2 gas to evaporate the solvent in the resist and complete the coating.

As a result, the thickness of the resist coated on the main surface (Wa) of the substrate (W) becomes constant. The reason for this constant thickness is that the amount of residual solvent Ω in the resist changes over time, and the interaction between this change in solvent amount and the speed change cancels out the effect of centrifugal force.
It can be considered that the film thickness is constant.

FIG. 2B and FIG. 2C show other embodiments, and FIG. 2B shows a resist-adhering 17-wall substrate (W) with 11
Rotate at a high speed of 1f for a time N, then decelerate to N2 at a constant acceleration for t2 hours l ~, continue to rotate at this N2 for t5 hours, repeat this same process multiple times υ, and finally The resist was rotated with N2 for 14 hours to evaporate the solvent in the resist and complete the coating. Further, FIG. 2C shows the substrate (W) to which the resist is attached.

After rotating at a quotient speed of N2 for a time, it is decelerated to N2 and t
The resist was rotated for 2 hours, and the same process was repeated several times.Finally, the resist was rotated for 13 hours using N5 to evaporate the solvent in the resist and complete the coating.

According to the methods of these embodiments, similar effects can be achieved for the same reasons as those of the embodiments described above.

Although the above-mentioned embodiment has been described for applying resist to a glass substrate (W), it can also be applied to processes such as applying resist to wafers used in the production of semi-solid integrated circuits. Needless to say. Further, the method of deceleration is not limited to the above-mentioned embodiments, and any method can be selected.

〔Effect of the invention〕

This invention applies high-speed rotation to the substrate on which the resist is attached at least at the beginning of coating, decelerated rotation in the middle of coating, and low-speed rotation at the end of coating, so that the film thickness of the resist applied to the substrate can be reduced from that of the conventional substrate. Compared to the case where only constant speed rotation was applied, it was possible to make the resist coating constant, and as a result, the quality of resist coating could be improved.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a resist coating apparatus used in an embodiment of the present invention, and FIGS. 2 (AXB) and (C) are drawings for explaining the coating method of the present invention. (1): Turntable (VV): Board (W
a): Main face fee/embedding Patent attorney rule Yu Chika (and 1 other person)

Claims (1)

[Claims] In a resist coating method in which a substrate having a resist attached to its main surface is rotated around an axis perpendicular to the main surface of the substrate,
A resist coating method characterized in that the substrate is subjected to high-speed rotation at least in the initial stage of coating, decelerated rotation in the middle of coating, and low-speed rotation in the final stage of coating.