JPS61206221A - Spin coating device - Google Patents

Abstract

PURPOSE:To reduce the quantity of air which comes in contact with the surface of the material to be coated as well as to obtain the uniform thickness of coated film by a method wherein an air feeding unit with which clean air is supplied into a cover is provided, and an air stream is used as the means of removing the grains scattered by centrifugal force after coating. CONSTITUTION:A splash preventing plate 9, having the top point a little upward of the position of a wafer surface on the outer circumference of a wafer 1, is provided in order to prevent the scattering of the fluid and the solid-state grains of the liquid resist on the wall surface of a cover 6 from the outer circumference of the wafer 1. An air blowing-out hole 10 is provided on the splash preventing plate 9, and clean air sent from the air feeding unit 11 is blown out from the blow-out hole 10. The grains scattered in circumferential direction of the wafer 1 are removed from a coating device by the clean air sent from the blow-out hole 10. Also, as a little grains are generated on the upper part of the wafer surface by the diffusion and the like of the liquid resist, the grains on the upper part of the wafer surface can also be removed by blowing the clean air into the clean-air device from an intake hole 12 located above the cover 6.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a spin coating apparatus used in the manufacture of semiconductors, etc., and in particular, a method for quickly removing droplets of a coating liquid or solidified fine particles from the spin coating apparatus, The present invention relates to a spin coating device that realizes an air flow within the coating device suitable for preventing re-adhesion to a coated object.

[Background of the invention]

First, FIG. 1 shows a resist coating apparatus used in the manufacture of semiconductors as an example of a spin coating apparatus.

The wafer 1, which is the object to be coated, is fixed by suction on a spinner 3 which is rotated by a motor 2, and the resist liquid 5 is dripped from a nozzle 4 placed above the surface of the wafer 1. Then, by the rotation of the spinner 3, the resist liquid 5 is supplied dropwise. The resist solution is uniformly spread over the surface of the wafer by the effect of centrifugal force, and after drying, a resist is formed. During this time, when the spinner 3 rotates, most of the dropwise supplied resist solution 5 is scattered from the outer periphery of the wafer 1, and after the liquid particles or the resist solution medium are vaporized, they float as solid particles in the resist coating device. It may stick to the wall or bounce off the wall.

If these particles re-deposit on the surface of the wafer, the resist film thickness becomes non-uniform, and solid particles, like foreign matter, cause product defects. Therefore, clean air from the manufacturing environment is generally sucked into the apparatus from the top surface of the cover 6 of the coating apparatus and exhausted from below the spinner 3 using the exhaust pump 7, and this air flow removes particles from the coating apparatus. ing. but,
Passing a large amount of air through the coating device affects the drying speed of the resist solution, and is inappropriate for the spin coating method in which the resist film thickness is controlled by the viscosity of the resist solution and the rotational speed of the spinner 3.

In addition, as a method of preventing the scattered resist solution from re-adhering to the wafer surface, a shielding plate 8t having a notch on the outer periphery of the wafer is provided as shown in FIG.
There is the method of No. 7836, or this example also uses an air flow to remove resist particles, and since the air flow with a volume equivalent to the displacement passes through a narrow notch on the outer periphery of the wafer 1, the wafer The resist solution dries quickly in the external area,
This causes non-uniform resist film thickness.

[Purpose of the invention]

Therefore, an object of the present invention is to use a clean air flow to remove the liquid particles of the coating solution scattered in the spin coating device or the solid particles of the coating solution solidified, so that these particles can be returned to the surface of the object to be coated. It is an object of the present invention to provide a spin coating device that suppresses the amount of air that comes into contact with the surface of an object to be coated and achieves a uniform coating film thickness when preventing adhesion.

[Summary of the invention]

The present invention includes a spinner that sucks and fixes a wafer and rotates it, a nozzle that supplies a coating liquid onto the wafer, a cover configured to surround the spinner, an air intake port on the nozzle side of the cover, and a nozzle that supplies a coating liquid onto the wafer. This is a spin coating device consisting of an intake and exhaust system with an exhaust port on the opposite side of the cover, and an air supply unit that supplies clean air inside the cover. An air stream is used as a means of removing the material from the coating device. In order to prevent this airflow from affecting the drying speed of the coating liquid on the wafer surface, clean air is blown out from below the wafer surface to the coating equipment, and an air volume slightly larger than this blown air volume is supplied to the coating equipment. By keeping the inside of the coating apparatus clean by exhausting air from below and preventing the scattered coating liquid particles from re-adhering to the wafer surface, a spin-coated film K with a high product yield can be realized.

[Embodiments of the invention]

Hereinafter, one embodiment of the present invention will be described in accordance with the third embodiment. In this embodiment, in order to prevent liquid and solid particles of the resist solution splashed from the outer circumference of the wafer 1 from bouncing off the wall surface of the cover 6 and scattering into the coating device, It is provided with a rebound prevention plate 9 having an apex slightly upward. The splash prevention plate 9 is provided with an air outlet 10, from which clean air sent from an air supply unit 11 that supplies clean air is blown out. Particles scattered in the circumferential direction of the wafer 1 are mainly removed from the coating device by clean air from the blow-off port 10, or particles are slightly generated above the wafer surface due to diffusion from the resist solution. Clean air from the manufacturing environment is also sucked into the apparatus from the intake port 12 above the wafer 6, and particles above the wafer surface are removed at the same time. The coating device is evacuated by an exhaust pump 7 located below the coating device. When the amount of intake air from the intake port 12 is extremely small, the following method is used for the exhaust system.

That is, a flow meter 13 is provided in the exhaust section of the coating device to check that all of the clean air supplied from the air supply unit is exhausted. Furthermore, the air supply unit 11, flow meter 13, and exhaust pump 7 are connected to a control system 14 composed of, for example, a 71-crore computer in order to control them. The control system 14 controls the air outlet 10 even when the amount of intake air from the intake port 12 changes due to fluctuations in air pressure in the manufacturing environment or when the amount of air supplied from the air supply unit 11 changes from the set amount. The exhaust volume is appropriately controlled so that air blown from the wafer does not flow back toward the wafer surface and cause floating particles to adhere to the wafer surface.

As described above, in the present invention, resist particles generated and floating in the coating apparatus are removed from the coating apparatus using clean air from the air supply unit 11.

Therefore, the inside of the coating apparatus can be kept clean, and the amount of air that comes into contact with the wafer 1 can be kept to the minimum amount necessary to remove particles floating on the wafer surface, and the rate of resist drying on the wafer surface can be reduced. It is possible to realize a spin coating device that has the effect of maintaining uniformity and has a high product yield. Furthermore, in the conventional manufacturing process, when resist adheres to the inside of the coating device, the coating device is stopped and the interior is cleaned in order to prevent the occurrence of defective products due to contamination caused by it. For example, a clean atmosphere can always be maintained above the wafer surface, which has the effect of reducing the number of cleaning times of the coating device and increasing the operating rate.

FIG. 4 shows the positional relationship between the spinner 3 and the outlet 10 in another embodiment of the present invention. In this embodiment, the splash prevention plate 9 shown in FIG. 3 is replaced with a flat plate 15, and the flat plate 15 is arranged so that the lower surface thereof is located above the wafer surface.The lower surface of the flat plate 15 has a clean air outlet 10'! ! - Yes. and,
The configuration of other parts is the same as the embodiment shown in FIG. Resist particles blown away from the wafer surface by centrifugal force are phenolic particles.
, and has the same effect as the embodiment shown in FIG.

FIG. 5 shows an example in which the invention is implemented by removing the anti-rebound plate 9 in FIG. 3. An example is shown in which the air outlet 10 is provided at a position on the wall surface of the cover 6 at the same height as the wafer surface. In addition, the 6th prisoner is composed of a 10t-tube with an outlet,
The structure is shown arranged at several locations on the outer periphery of the wafer 1. In any of the embodiments, there is an effect that resist particles scattered from the wafer surface can be removed from the coating device by clean air from the outlet 10.

FIG. 7 shows an example in which the outlet 10 is provided at a position below the spinner 3, that is, on the inner wall side of the coating device. In this embodiment, the piping from the air supply unit 11 shown in FIG. 3 can also be installed inside the coating apparatus, and the appearance of the coating apparatus can be simplified.

〔Effect of the invention〕

According to the present invention, floating particles generated by scattering of the coating liquid due to centrifugal force in the spin coating device are removed by clean air blown out from nine air outlets installed in the spin coating device, so that the inside of the coating device can be cleaned. It can be maintained cleanly, and the amount of air that comes into contact with the object to be coated is kept to the minimum amount necessary to remove gold particles floating on the surface of the object to be coated, and the drying rate of the coating liquid is kept uniform. This has the effect of realizing a spin coating device with a high product yield and high operating rate.

[Brief explanation of the drawing]

Fig. 1 is a cross-sectional view of a conventional resist coating device, Fig. 2 is a sectional view of a resist coating device equipped with a shielding plate for preventing splashing of resist liquid, and Fig. 3 is a cross-sectional view of a resist coating device according to an embodiment of the present invention. and FIGS. 4 to 7 are cross-sectional views of a resist coating device showing the positional relationship between a spinner and an air outlet according to another embodiment of the present invention. 1... Wafer, 2... Motor, 3... Spinner, 4
... Nozzle, 5... Resist liquid, 6... Cover,
7... Exhaust pump, 8... Shielding plate, 9... Splash prevention plate, 10... Air outlet, 11... Air supply unit, 12... Intake port, 13... Flow meter , 14... control system, 15... flat plate. 1st mouth light 2nd mouth 3rd mouth ≠ eye

Claims (1)

[Scope of Claims] 1. A spinner for suctioning and fixing a wafer and rotating it, a nozzle for supplying a coating liquid onto the wafer, a cover configured to surround the spinner, and an air intake on the nozzle side of the cover. A spin coating apparatus comprising an intake/exhaust system having an opening and an exhaust opening on the opposite side of the nozzle to the wafer, characterized in that an air supply unit is provided for supplying clean air into the cover. Spin coating equipment. 2. In claim 1, the cover is provided with a splash prevention plate having an apex slightly above the wafer surface on the outer periphery of the wafer, and the splash prevention plate is provided with a clean air outlet. A spin coating device characterized by being provided with. 3. In claim 1, the cover includes a flat plate-shaped anti-rebound element having a lower surface slightly above the position of the wafer surface on the outer periphery of the wafer and disposed on the same plane as the wafer surface. 1. A spin coating device comprising: a plate; and a clean air outlet provided on the bottom surface of the flat anti-repellent plate. 4. The spin coating apparatus according to claim 1, wherein the cover has a clean air outlet opened at a position approximately the same as the wafer surface. 5. The spin coating apparatus according to claim 1, wherein a tube having an opening at approximately the same position as the wafer surface is arranged in the cover to serve as a clean air outlet. 6. Claim 1, characterized in that a clean air outlet, which is disposed at the lower end of the spinner for sucking and fixing the wafer and rotating the wafer, is opened to blow out clean air toward the outer periphery of the spinner. Spin coating equipment.