JPH06124487A - Spin coating apparatus - Google Patents

Abstract

PURPOSE:To manufacture an organic thin film with high efficiency and at low costs by a method wherein the volume of a collection and stock container for a coating agent is made smaller than that of a supply and stock container and a filtration means is provided in a coating-agent line. CONSTITUTION:At the initial stage of a coating operation, a spin table 10 is turned at low speed, it is then turned at high speed and a coating agent is shaken off. The coating agent which has been scattered is gathered by a collection kettle 11, and it is gathered in a collection and stock container 18 via a collection line 12 and a three-way valve 14. When it reaches a set volume, it is pressurized from an air valve 13 for pressurization use and it is returned to a supply container 2. At this time, the volume of the container 18 is decided by the permissible number of circulations of the coating agent to be used. When the coating agent can be used repeatedly N times, the volume is set at NX(W-N) (where W represents the coating amount of the coating agent and V represents the amount of the coating agent used), and it is made smaller than the volume of the container 2. The content of dust particles in the coating agent which has been collected is increased as the number of collection operations is increased. The dust particles are filtered and removed by a filter 15 installed in the coating-agent supply line 5.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a spin coater.

[0002]

2. Description of the Related Art In recent years, an optical information recording / reproducing apparatus for irradiating a laser beam to record information on an optical recording medium and reproducing the recorded information has been widely used. As optical disk substrates used in optical information recording / reproducing devices, glass and plastic with excellent optical characteristics and mechanical dimensional accuracy are used, but continuous injection molding is possible, high productivity, low material Plastic is mainly used because it has advantages such as price. In an optical disc using a plastic substrate, the recording / reproducing characteristics of the optical disc may be deteriorated when the substrate surface is scratched, the substrate surface is contaminated, or dust is attached to the substrate surface. In order to prevent dust from adhering to the surface of the substrate where the laser light is incident,
It is common to apply an organic thin film such as an ultraviolet curable coating agent having high hardness and smoothness. Further, when a metal film used as a recording film of an optical disk comes into contact with oxygen, water, corrosive gas, etc., it may be eroded and deteriorated. Techniques for protecting the are well known. As a method for applying these organic thin films to the surface of the optical disk substrate, the spin coating method is generally adopted because a uniform thin film can be efficiently formed.

[0003]

As described above, the spin coating method is excellent as a method for forming an organic thin film on an optical disk substrate, but when spin coating is performed, the spin coating method is required to form a desired thin film. 8 to 1 of the amount of the agent
It has the disadvantage of requiring 0 times the amount. That is,
When forming a coating agent on a substrate, first apply the coating agent from a nozzle in a low speed rotation state, then increase the number of rotations,
After forming a thin film on the substrate surface while shaking off the coating agent, the coating agent is cured by an ultraviolet lamp or the like to obtain a thin film. Here, most of the coating agent is scattered and removed from the substrate surface during high-speed rotation. Therefore, unless the coating agent used for spin coating is collected and reused, the yield of the coating agent decreases, and Cannot be manufactured at low cost. In particular, since the demands on the quality of optical disks have recently become strict, it is necessary to strictly control the quality of the content of foreign substances in the coating agent used and the film thickness fluctuation due to the viscosity change due to the mixing of water. It is no longer possible to maintain sufficient quality with the recovery device attached to the coater.

A conventional spin coater will be described with reference to FIG. 2 showing a coating agent system diagram of a conventional spin coater with a recovery device. The coating agent extruded from the supply stock container (22) having the safety valve (34) containing the coating agent (21) through the pressurized air line (23) with the valve (24) by the pressurized air is the coating agent. It is applied to the substrate (29) fixed to the spin table (30) from the nozzle (28) of the dispenser (27) through the supply line (25) and the three-way valve (26). In the initial stage of coating, the spin table (30) is rotated at a low speed and then at a high speed to shake off the coating agent. The scattered coating agent is collected by the recovery pot (31), passes through the recovery line (32), and is supplied by the pump (33) to the stock container (22).
Will be collected. When such a conventional spin coater is used, when the coating amount of the coating agent is W and the amount of the coating agent used for forming the organic thin film is V, the recovered coating agent amount is W.
-V. When the recovered coating agent is continuously returned while being returned to the container having the supply stock amount T, T /
It can be recycled (WV) times, but the proportion of the coating agent that is collected and reused increases as the number of times of coating increases. As a result, the viscosity of the coating agent changes, the coating amount fluctuates, and the proportion of dust contained in the coating agent increases. It has been common to discard the entire coating agent in the supply tank of the apparatus, or discard the entire coating agent used once without recovering it. Therefore, the yield of the coating agent is low and it is difficult to reduce the manufacturing cost.

An object of the present invention is to provide a spin coater capable of forming an organic thin film with high efficiency and low cost.

[0006]

According to the present invention, the above object is to provide a stock container for stocking a coating agent for supplying the coating agent to an object to be coated, and a coat recovered after forming a thin film. And a collection stock container for stocking the coating agent, the volume of the collection stock container is smaller than the volume of the supply stock container, and a coating agent filtering means is provided in the coating agent line. To be done.

[0007]

EXAMPLES The present invention will be described in detail with reference to FIG. 1 showing a system diagram of a coating agent of an example of the spin coating apparatus of the present invention. The coating agent extruded by the pressurized air from the supply stock container (2) having the safety valve (14) containing the coating agent (1) through the pressurized air line (3) with the valve (4). Through the supply line (5),
After passing through the filter (15) having the drain valve (16) through the three-way valve (6), it is applied from the nozzle (8) of the dispenser (7) to the substrate (9) fixed to the spin table (10). It Usually, the spin table (10) is rotated at a low speed in the initial stage of application, and then rotated at a high speed to shake off the coating agent. The scattering coating agent (1
Collected in 1) passes through the recovery line (12), enters the recovery stock container (18) through the three-way valve (14). Pressurizing air valve (13) when it reaches a preset amount
The recovery line (1
7) and returned to the feed stock container (2). The size of the recovery stock container in this apparatus is determined by the allowable number of circulation of the coating agent used. That is, the allowable number of times is determined by previously testing the scattering of volatile matter, the change in viscosity due to the mixing of water, the degree of quality deterioration, and the like. If there is no problem in repeating and collecting and using up to N times, the size of the recovery stock container becomes N × (W−V) (W: coating amount of coating agent, V: used for forming organic thin film) Amount of coating agent). The volume of the recovery stock container (18) is smaller than the volume T of the supply stock container (2). That is, T ≧ N × (W
-V) is satisfied. Further, the proportion of dust contained in the recovered coating agent increases as the number of times of recovery is repeated. This is because dust carried by the substrate supplied to the spin coater mixes into the recovery coat, and the filter (1) provided in the coating agent supply line (5) is used.
The dust is filtered in 5).

An experimental example using the spin coater of the present invention will be described. A magneto-optical disk substrate was formed by injection molding using a polycarbonate resin, and a magneto-optical disk containing a rare earth-transition metal amorphous alloy as a main component was formed on the substrate by sputtering. A UV coating resin SD-301 manufactured by Dainippon Ink and Chemicals, Inc. was applied onto the magneto-optical recording film by a spin coating method (rotation speed at high speed:
It was applied at 2000 rpm) and immediately cured for 10 seconds using a high pressure mercury lamp (power: 3 kW). When the protective film thus obtained was measured by a gravimetric method, the film thickness was 10 μm. In the spin coater used here, the supply stock container was 10 liters, the recovery stock container was 8 liters, and the coating amount per time was 0.1 g. The filter mesh used was 0.2 μm. When recovery was performed using this device and continuous coating was continued, the yield of the coating agent was significantly improved as compared with the conventional device, and good protective film performance was obtained.

The spin coater used for manufacturing the optical disc has been described above in detail, but the application of the spin coater of the present invention is not limited to the optical disc.

[0010]

According to the spin coater of the present invention, an organic thin film can be manufactured with high efficiency and low cost.

[Brief description of drawings]

FIG. 1 is a schematic diagram of a coating agent system of an example of a spin coating apparatus of the present invention.

FIG. 2 is a schematic diagram of a coating agent system of a conventional spin coater.

[Explanation of symbols]

 1 coating agent 2 supply stock container 5 coating agent supply line 15 filter 18 recovery stock container

Claims (1)

[Claims] 1. A recovery stock container comprising a supply stock container for stocking the coating agent for supplying the coating agent to an object to be coated, and a recovery stock container for stocking the coating agent recovered after thin film formation. Is smaller than the volume of the supply stock container, and a coating agent filtering means is provided in the coating agent line.