JPS5855976Y2 - spin coater - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improved structure of a spin coater that rotates at high speed.

Conventionally, for example, when manufacturing semiconductor devices, a photo process has been used in which a photoresist film is applied to the surface of a wafer and a pattern of the photoresist film is formed on the wafer using the exposure and development method used in photography. In this case, the equipment that applies the resist film is called a spin coater, which drops the resist onto the wafer and then rotates the wafer at high speed so that the rotation spreads the resist onto the surface and creates a uniform film thickness. It used to be.

The thickness of a resist film coated on a wafer is usually around 1 μm, but the thickness of the resist applied to a pattern mask used in the photo process is as thin as several 100 OA.

Additionally, the resist film pattern on the wafer surface tends to become thinner as semiconductor devices become smaller, but in order to coat such a thin resist film, it is necessary to use a highly viscous resist material with an organic solvent. The resist material is sufficiently diluted to have a low viscosity and is dropped onto the surface of the material to be coated, such as a wafer or mask.
Due to high-speed rotation, excess resist material is scattered from the surface,
When it hits the surrounding side walls, the organic solvent evaporates, becomes highly viscous, and bounces back onto the material to be coated, causing unevenness in the resist film.

As described above, unevenness in the thickness of the photoresist film is a fatal flaw in a spin coater whose purpose is to make the film thickness uniform, and it is an important problem that impairs the precision of semiconductor device patterning. This becomes a problem.

The present invention is a spin coater that eliminates these drawbacks. Its feature is a structure in which rotating fins are attached around a rotating support base that rotates at high speed while holding the material to be coated onto which the coating material has been dripped. This will be explained in detail below.

FIG. 1 is a plan view of an embodiment of a spin coater according to the present invention, and FIG. 2 is a sectional view thereof.

In the figure, reference numeral 1 denotes a rotating support that holds a material to be coated (not shown) by vacuum suction from the back side, and is connected to a drive motor 2 by a rotating shaft 3, and a surrounding side wall 4 surrounding the rotating support 1. There are exhaust ports 5 in two directions to suck the evaporated organic solvent.

A large number of fins 6 are provided near the side wall 4 at an intermediate position, and a cylindrical shaft 7 coaxial with the rotating shaft 3 is rotated by a drive motor (not shown) in the horizontal direction at several hundreds of rpm. is rotating.

The fins 6 are attached in the tangential direction of the outer circumference of the rotary support base 1.

The rotational speed of the rotation support table 1 is 3000 r, p. m, and the fins 6 rotate in the opposite direction.

If the fins 6 are not installed, the excess resist material that drips onto the material to be coated on the rotary support base 1 and is thrown around by the rotation will be repelled by the surrounding side wall 4 and be deposited onto the material to be coated again. Attach to.

Such drawbacks were a problem with conventional spin coaters, but when the fins 6 are attached and rotated as in the present invention,
Fin 6 blocks splashes.

The particles often adhere to the back surface of the fin 6, that is, a surface that is less visible than the rotating support 1, and even if they fly and hit the front surface of the fin, that is, the surface facing the rotating support 1, they are bounced back in the opposite direction.

However, if the fins 6 remain stationary, wafers with resist film unevenness of several to 10% will be generated when the material to be coated is a wafer, but this will scatter from the wafer surface and cause the resist film to become uneven on the fin surface. This is thought to be due to the fact that the resist film is scattered more finely when the fins 6 are rotated, and this is greatly different from the result of implementing the present invention in which the fins 6 are rotated, and in the present invention, there is almost no resist film unevenness.

As can be seen from the above embodiments, the present invention achieves
It can prevent the resist film from peeling.
The implementation effect is remarkable, and it can be applied to the formation of thin photoresist films for semiconductor devices that will become smaller in the future, and will be useful for improving the reliability of those devices.

Note that the present invention can be applied not only to spin coaters for semiconductors but also to other devices having the same purpose.

[Brief explanation of drawings]

Fig. 1 is a plan view of the present invention, and Fig. 2 is a cross-sectional view of the present invention.
is the rotating shaft, 4 is the surrounding side wall, 5 is the exhaust port, 6 is the fin, 7
indicates its rotating cylindrical axis.

Claims (1)

[Scope of utility model registration request] A spin coater characterized by having rotating fins attached around a rotating support base that rotates at high speed while holding a material to be coated onto which a coating material has been dripped.