JPH02216816A - Resist coating method - Google Patents

Abstract

PURPOSE:To enable a resist film of uniform thickness to be coated on a wafer in a short time by dripping a resist liquid on the wafer, allowing the resist liquid to flow over the wafer while duct-pulling the periphery and rotating a turntable at high speed, stopping revolution, and then performing duct-sucking at a higher suction, force and then performing drying. CONSTITUTION:After performing vacuum chuck of a wafer 11 on a turntable 3, degree of opening of a valve 10 is adjusted by signal from a controller 6, resist liquid is dripped on a wafer 11 from a nozzle 7 through a resist wave introduction pipe 8 while performing duct-sucking, driving a motor 4 by signal from the controller 6 to rotate the wafer 11 on the turntable 3 at high speed, and allowing the resist liquid to flow over the entire surface of the wafer 11. Then, the motor 4 is stopped by signal from the controller 6 and the rotation of the turntable 3 is stopped. At the same time, opening of the valve 10 is enlarged to increase duct pressure and continue duct-suction. At this time, strength shown by an arrow 12 within a CUP 1 and a room 2 becomes larger, thus drying the resist film with viscosity on the wafer 11.

Description

[Detailed description of the invention] [Purpose of the invention] (Industrial application field) The present invention relates to a resist coating method.

(Prior art) In the manufacture of semiconductor devices, a resist film is formed on a wafer coated with an oxide film or various conductive films, and a desired resist pattern is formed by exposure and development. A process of selectively etching the underlying film to form a pattern using the resist pattern as a mask, and a process of ion-implanting impurities into the wafer surface using the resist pattern as a mask are performed.

By the way, the following method has been conventionally employed to form (coat) a resist film on the wafer. That is, a resist solution is dropped onto a wafer vacuum chucked on a turntable, and the turntable is rotated at high speed while drawing a duct around the wafer to spread the resist solution onto the wafer, and then high-speed rotation is continued. A resist film is coated on the wafer after drying.

However, in the conventional method described above, since drying is performed while rotating at high speed, the viscous resist film is dried while flowing, resulting in the problem that the resist film after drying is wavy and the film thickness is uneven. there were.

(Problems to be Solved by the Invention) The present invention has been made in order to solve the above-mentioned conventional problems, and provides a resist coating method that can coat a resist film with a uniform thickness on a wafer in a short time. This is what I am trying to do.

[Structure of the Invention] (Means for Solving the Problems) The present invention involves dropping a resist solution onto a wafer vacuum chucked on a turntable, rotating the turntable at high speed while drawing a duct around the wafer, and applying the resist solution to the wafer. This resist coating method is characterized in that after the liquid is cast onto the wafer, the rotation is stopped and the resist liquid is dried while being ducted with a higher suction force than when the resist liquid was cast.

When casting the resist solution onto the wafer, the duct is used to suck the resist solution that scatters from the wafer during high-speed rotation into the duct, and the resist solution that rebounds from the cup around the turntable is poured onto the wafer again. This is to prevent adhesion.

The high rotational speed for casting the resist solution onto the wafer is preferably in the range of 1500 to 3500 rpm.

(Function) According to the present invention, a resist solution is dropped onto a wafer vacuum chucked on a turntable, and the turntable is rotated at high speed while drawing a duct around the wafer to cast the resist solution onto the wafer. Accordingly, a resist film having uniform thickness and viscosity can be formed. After that, the rotation of the turntable is stopped and the resist solution is dried while being ducted with a higher suction force than when it was cast, so that the resist film can be dried in a short time without causing waving as in conventional methods. Therefore, a resist film having a uniform thickness can be applied onto the wafer.

(Example) Hereinafter, an example of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a schematic diagram showing a resist coating apparatus used in this example. 1 in the figure is a cup, and a chamber 2 for gas circulation is communicated with the lower part of this cup 1. A turntable 3 having a vacuum chuck function is disposed inside the cup 1, and a cylindrical shaft 5 rotated by a motor 4 disposed above the chamber 2 is connected to the bottom of the table 3. ing. Note that the rotation speed of this motor 4 is controlled by a controller B.

A nozzle 1 for dropping resist liquid is arranged above the turntable 3, and a resist liquid introduction pipe 8 is connected to the nozzle 7. A duct 9 is connected to the lower side wall of the chamber 2, and this duct 9 has a
A valve IO whose opening degree is adjusted by the controller 6 is interposed.

Next, a resist coating method using the coating apparatus will be explained.

First, after the wafer 11 is vacuum chucked on the turntable 3, the opening degree of the valve 10 is adjusted by the signal from the controller 6, as shown in the timing chart of FIG. 2, and the duct pressure is set to 0.4 kg/c. While drawing the duct under the conditions of 2, the resist liquid is passed through the nozzle 7 through the resist liquid introduction pipe 8 to a viscosity of 1.
While dropping a 4 cP resist solution onto the wafer 11,
The motor 4 was driven by a signal from the controller 6 to rotate the wafer 11 on the turntable 3 at a high speed of 200 rpm to cast the resist solution over the entire surface of the wafer 11. Subsequently, as shown in FIG. 2, the motor 4 is stopped by a signal from the controller 6 to stop the rotation of the turntable 3, and at the same time, the opening degree of the valve 10 is increased to raise the duct pressure to 2K.
g/am2 and continued to pull the duct for 80 to 70 seconds. At this time, the flow shown by the arrow 12 in the cup 1 and the chamber 2 became strong, and the viscous resist film on the wafer 11 was dried and coated on the wafer 11.

When the resist film coated on the wafer 11 was observed, it was found that the resist film had an extremely uniform thickness.

[Effects of the Invention] As detailed above, according to the resist coating method of the present invention, a resist film of uniform thickness can be coated on a wafer in a short time,
Furthermore, by exposing and developing the applied resist film, it has remarkable effects such as being able to form a highly accurate and fine resist pattern suitable for microfabrication of semiconductor devices with good reproducibility.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing one form of a resist coating apparatus used in an example of the present invention, and FIG. 2 is a timing chart showing the wafer rotation speed and duct pressure in the resist film coating process. ■...cup, 8...turntable, 4...motor, 6...controller, ? ...Nozzle, 9...Duct, lO...Valve, 11...Wafer.

Claims (1)

[Claims] A resist solution is dropped onto a wafer that is vacuum chucked on a turntable, and the turntable is rotated at high speed while drawing a duct around the wafer to spread the resist solution onto the wafer. A resist coating method characterized by drying the resist solution while drawing it through a duct with a higher suction force than when casting the resist solution.