JPS63229168A - Coating apparatus - Google Patents

Abstract

PURPOSE:To certainly prevent the re-adhesion of a splash to an object to be coated, by providing a resist coating apparatus for a wafer, with a splash preventing part having an embossed surface to the inner peripheral surface of a treatment container. CONSTITUTION:A curved surface part 22 whose inside becomes concave is formed to the part opposed to a wafer 6 of a treatment container 1 in an annular shape and an embossed surface consisting of numberless protruding parts 23 and recessed parts 24 is provided to the curved surface part 22 by carving. These protruding and recessed parts 24 are relatively fine and formed by knurling processing so that the chips thereof become sharp. In coating, when a resist solution 17 is dripped and diffused in a radial direction by centrifugal force, splashes 19 are radially scattered in the outward direction from the outer peripheral edge of the wafer 6 but prevented from turning back so as to return to the wafer 6 by the embossed surface of the splash preventing part 21 and, therefore, the re-adhesion of the splashes 19 to the wafer 6 is prevented.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a coating technology, particularly a technology for applying a coating material while an object to be coated is accommodated in a processing container, and is useful, for example, in the manufacture of electronic devices. , relates to a technique effective for applying resist onto a wafer.

[Conventional technology]

In the manufacturing of electronic devices, a coating device that coats resist onto a wafer is used to place and hold the wafer on a rotatable spin head installed inside a processing container, and sprays resist liquid onto the surface of the wafer while rotating the wafer. Some are configured to apply resist by supplying
(See Japanese Patent Publication No. 53-37189).

In this resist coating apparatus, there is a risk that the resist liquid scatters around the wafer during high-speed rotation, collides with the inner circumferential surface of the processing container, rebounds, and re-adheres to the wafer.

Therefore, a technique has been considered in which the inner circumferential surface of the wafer is tilted downward and a downward exhaust flow is formed in the space around the wafer, thereby discharging the bounced droplets so that they do not attach to the wafer again.

An example of a spinner coating technique that describes the spinner coating technique is "Electronic Materials November 1986 Special Issue" published by Kogyo Research Association Co., Ltd., November 18, 1986, pages 97 to 100.

[Problem that the invention seeks to solve]

In such resist coating equipment, droplets that bounce off the sloped surface that is easy to process may re-adhere to the wafer, and if the exhaust speed is increased to prevent this, variations in the coating thickness distribution may occur. The inventor of the present invention has discovered that there is a problem in that.

An object of the present invention is to provide a coating technique that can reliably prevent re-adhesion due to splashing of the coating material.

The above and other objects and novel features of the present invention will become apparent from the description of this specification and the accompanying drawings.

[Means for solving problems]

An overview of typical inventions disclosed in this application is as follows.

That is, a repelling prevention portion having an uneven surface is disposed on the inner peripheral surface of a processing container that accommodates an object to be coated and applies a coating material so as to face the outer periphery of the object to be coated.

[Effect]

According to the above-mentioned means, since the splash prevention part having the uneven surface is provided on the inner circumferential surface of the processing container, the flying droplets collide with the uneven surface and are atomized by the protrusions. Alternatively, the droplets will be absorbed into the recesses and will not bounce back to the original direction, thus reliably preventing the droplets from re-adhering to the object to be coated.

(Embodiment) FIG. 1 is a longitudinal cross-sectional view showing a resist coating apparatus according to an embodiment of the present invention, and FIG. 2 is an enlarged partial cross-sectional view for explaining its operation.

In this embodiment, this resist coating apparatus has a processing capacity It
The container 1 is formed into a substantially cylindrical shape with open upper and lower surfaces.

Processing capacity! A substantially cylindrical bottom plate 2 with a closed top surface is concentrically disposed in the bottom opening of the il, and a rotating shaft 3 rotated by a suitable drive device 4 such as a servo motor is mounted on the bottom plate 2. , are placed on the center line and inserted.

A spin head 5 is arranged and fixed to the upper end of the rotating shaft 3 in the processing container l so as to be able to rotate horizontally, and the spin head 5 is capable of holding a wafer 6 as an object to be coated by vacuum suction. It is configured. A plurality of air supply lowers are provided around the rotation shaft 3 of the bottom plate 20 so as to supply airflow toward the back surface of the spin head 5.
A circular annular hollow exhaust port 8 is substantially formed between the outer periphery of the cylindrical portion and the inner periphery of the processing container l.

On the other hand, a cover 10 formed in a substantially circular ring shape is concentrically disposed at the upper opening of the processing container l and is installed so as to be able to move up and down relatively. An air supply port 9 having a circular annular hollow shape is substantially formed between the cover 10 and the inner periphery of the cover 10, and a circular ring-shaped portion 11 having a substantially inverted triangular cross section is formed at the lower end of the cover 10. A filter unit 12 formed into a substantially disk-shaped hollow body is fitted into the cover 10, and the hollow portion of this unit 12 substantially forms a buffer portion 13. That is, a plurality of air supply ports 14 are provided on the upper wall of the unit 12, and an upper space and a buffer section 13 are provided.
A plurality of air outlets 15 are provided on the lower wall of the unit 12 so as to communicate the buffer section 13 with the lower space. In the filter unit 12, a dropping tube 16 for dropping a resist liquid 17 as a coating material is arranged concentrically and inserted vertically downward.

A splash prevention part 21 is disposed in the processing container 1 so as to face the outer circumference of the wafer 6 held by the spin head 5, and this splash prevention part 21 protects the resist liquid from splashing from the wafer 6, as will be described later. The structure is such that it can prevent the particles from adhering to the wafer 6 again. That is, in a portion of the processing container 1 facing the wafer 6, a curved surface portion 22 having a concave inner side is formed in an annular shape. An uneven surface is engraved. These convex portions 23 and concave portions 24 are formed to be relatively thin and have sharp tips, and can be created by knurling, etching, or by implanting numerous needles.

Next, the effect will be explained.

A wafer 6 as an object to be coated is placed on a spin head 5 and held by suitable means such as vacuum suction, and then rotated via a rotation shaft 3 by a drive device 4. When this rotation becomes stable, the dripping tube 16 is passed from the dripping tube 16 to the register) -?
When &17 is dropped onto the center of the wafer 6, the resist liquid 17 is diffused in the radial direction due to centrifugal force, so that a coating 1!1118 is formed on the surface of the wafer 6.

At this time, as shown by the solid line arrow in FIG. The airflow A11 flows radially outward along the back surface of the wafer from the air lower toward the exhaust port 8, and on the surface of the wafer 6, the airflow flows from the outlet 15 group of the filter unit 12 toward the exhaust port 8 toward the wafer surface. After being blown gently, an airflow A3 is formed which flows outward in the radial direction.

At this time, since the airflow from the group of outlet ports 15 in the filter unit 12 is supplied to the group of outlet ports 15 through the buffer section 13, the flow velocity, pressure, and flow rate are uniform throughout the group of outlet ports 15. It will be equalized and will be blown out very gently. As a result, the applied resist liquid is dried uniformly over the entire surface, so that the applied resist liquid l1j1 formed on the wafer 6 is
The film thickness distribution of No. 18 is made uniform throughout.

When the resist liquid 17 is dropped and dispersed in the radial direction by centrifugal force, droplets 19 are scattered radially outward from the outer peripheral edge of the wafer 6 .

By the way, if the inner peripheral surface of the processing container is formed as a flat surface, the resist liquid droplets will bounce off the flat surface and, depending on the angle of incidence with respect to the flat surface and the direction of the airflow, may return to the original direction in which they came. It will return and re-deposit onto the wafer. If the droplets re-deposit on the wafer in this manner, the resist coated surface may be substantially damaged, resulting in improper lithography processing.

However, in this embodiment, the splash prevention part 21 is formed on the inner peripheral surface of the processing container l, so that the droplets 19 flying from the wafer 6 are prevented from bouncing back to the wafer 6. Therefore, the droplets 19 are prevented from re-adhering to the wafer 6.

That is, as shown in FIG. 2, when resist liquid droplets 19 collide with the tip of the convex portion 23, the droplets 19 are crushed and lose most of their kinetic energy, so they return to the direction from which they came. Never.

In addition, when the droplets 19 are crushed, they become fine particles, so
The air supply port 9 and the exhaust port 8 make it extremely easy to ride the vertical downward airflow A1 formed near the rebound portion 21, and the air is reliably discharged to the exhaust port 8 side (in the unlikely event that the air flows in the direction of the wafer 6) radially outward airflow At,/'s
will be easily pushed back. These can obtain sufficient effects even if the pumping speed is suppressed.

On the other hand, the splashes 19 of the resist liquid 17 are on the inner wall surface of the recess 24 (
This corresponds to the outer wall surface of the convex portion 23. ), the second
As shown in the figure, the light is repeatedly reflected between the walls and loses its kinetic energy, and then is guided to the bottom of the recess 24 and absorbed.

When the application of the resist liquid to the wafer 6 is completed,
The cover 10 is raised relative to the processing container 1, and the wafer 6 on which the coating film has been formed is taken out from the upper opening of the processing container 1.

According to the embodiment described above, the following effects can be obtained.

(11 By providing a splash prevention part having an uneven surface on the inner peripheral surface of the processing container, it is possible to prevent droplets of the coating liquid that have come from the object to be coated from rebounding toward the object to be coated. Re-adhesion to the object to be coated can be prevented.

(2) By preventing the droplets from re-adhering to the object to be coated, the quality of the coating film can be improved, so the reliability of the coating operation can be improved.

(3) By improving the quality of the coating film and the reliability of the work, if the coating film is a resist liquid film, the quality and reliability of the lithography process can be improved.
Product manufacturing yield can be increased.

(4) By forming a discharge airflow in the space adjacent to the splash prevention part, the fine particles of the coating material crushed in the splash prevention part can be carried by the airflow and discharged elsewhere, so they can be discharged to other places. Redeposition can be reliably prevented.

(5) By preventing the splash itself caused by the collision of the coating material against the inner peripheral surface of the processing container, the exhaust speed of the push-back airflow to prevent the re-deposition of the splashed droplets can be suppressed, thereby increasing the exhaust speed. This makes it possible to avoid unevenness in the film thickness distribution of the coating film.

Although the invention made by the present inventor has been specifically explained based on Examples above, the present invention is not limited to the Examples and can be modified in various ways without departing from the gist thereof. Not even.

For example, the uneven surface of the rebound prevention part can be formed not only by knurling, etching, or needle implantation, but also by forming a net 25 made of a wire with a diameter of lI in the processing container 1, as shown in FIG. It may also be formed by means of laying it on the inner circumferential surface.

In the above explanation, the invention made by the present inventor was mainly applied to an apparatus for coating a resist on a wafer, which is the background field of application of the invention, but the invention is not limited to this. It can also be used when applying.

〔Effect of the invention〕

A brief explanation of the effects obtained by typical inventions disclosed in this application is as follows.

By providing a splash prevention part with an uneven surface on the inner circumferential surface of the processing container, even if droplets of coating material flying from the object to be coated collide with the inner circumferential surface of the processing container, they will not bounce back toward the object to be coated. Therefore, it is possible to reliably prevent droplets from re-adhering to the object to be coated.

[Brief explanation of drawings]

FIG. 1 is a longitudinal cross-sectional view showing a resist coating apparatus according to an embodiment of the present invention, and FIG. 2 is an enlarged partial cross-sectional view for explaining its operation. FIG. 3 is an enlarged partial sectional view showing another embodiment of the present invention. l...processing container, 2...bottom plate, 3...rotating shaft, 4
... Drive device, 5... Spin head, 6... Wafer (object to be coated), 7.9.14... Air supply port, 8...
Exhaust port, 10... Cover, 12... Filter unit, 13... 1 buffer chamber, 15... Air outlet, 1G.
...Dripping tube, 17...Resist liquid (coating liquid), 18.
...Coating film, 19.: Splash, 21.. Splash prevention portion, 22.. Curved surface, 23.. Convex portion, 24.. Concave portion, 25.. Net (uneven surface). Figure 1

Claims (1)

[Scope of Claims] 1. A rebound prevention portion having an uneven surface is disposed on the inner peripheral surface of a processing container that accommodates an object to be coated and applies a coating material so as to face the outer periphery of the object to be coated. A coating device featuring: 2. The coating device according to claim 1, wherein the anti-repellent portion is constituted by a group of pointed convex portions and concave portions. 3. The coating device according to claim 1, wherein the splash prevention part is constituted by a net. 4. The coating device according to claim 1, wherein an exhaust airflow is formed in the vicinity of the splash prevention portion.