JPS60138925A - Application of resist - Google Patents

Abstract

PURPOSE:To unify the film thickness of a resist and to reduce the loadings of the resist when a flat board type substance to be applied with the resist is rotated, and the resist is to be applied to the prescribed thickness on the surface thereof by a method wherein the rotating speed of the substance to be applied is changed over two stages of an initial low speed and a later high speed. CONSTITUTION:A substance 1 to be applied with a resist is fixed on a spin head 2, and the low speed rotation of the substance 1 to be applied with the resist is started. Then the resist A is dropped to be supplied immediately to the center of rotation of the rotating substance 1 to be applied with the resist from a nozzle 3, and supply is stopped when the resist A is extended over the whole surface of the substance 1 to be applied with the resist. After then, the substance 1 to be applied is rotated at the prescribed high speed, the excessive resist A is scattered to the periphery of the substance 1 to be applied, and thickness of the resist A on the substance 1 to be applied is made to the prescribed value.

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Technical Field of the Invention The present invention relates to a method of resist coating in photolithography technology.

(bl Background of technology In manufacturing semiconductor chips that form the main body of semiconductor devices,
Photolithography technology applied to wafer processing and manufacturing of masks necessary for the processing includes a resist coating process.

For resist coating, it is important that the thickness of the coating be uniform, so a flat object to be coated, such as a wafer or a mask substrate, is rotated at a predetermined speed parallel to the surface of the object to be coated. A method of applying a resist to a predetermined thickness is generally used.

(C) Prior art and problems Figures 1, 2, and 3 are a plan view tal and a side view (bl
, FIG. 4 is a diagram showing the time course, and FIG. 5 is a diagram showing the state of resist spreading failure, where 1 is the object to be coated, 2 is the spin head, 3 is the nozzle, A is the resist, Sl, S
2 indicates the rotation speed, and a, bsc, and d indicate the time, respectively.

When applying resist A to a flat plate-shaped object 1 such as a wafer or a mask substrate, the object to be applied is placed on a spin head 2 that rotates the object, as shown in FIG. Fix it with a vacuum chuck or the like, and while the workpiece 1 is stationary, apply the register) A from the nozzle 3 to the workpiece 1.
Apply dropwise to the surface. Thereafter, as shown in FIG. 2, the spin head 2 is driven to rotate the object 1 at a low speed (rotation speed S1, for example, about 1100 Orp).
The resist A on top is spread over the entire surface of the object 1 to be coated.

Next, as shown in FIG. 3, the object to be coated 1 is rotated at a predetermined high speed (rotation speed S2, for example, about 500 rpm), and
The excess resist A is scattered around the object 1 to be coated, and the thickness of the resist A on the object 1 to be coated is set to a predetermined value (for example, about 1
μm).

The time course of the operation of this embodiment is as shown in FIG. 4, where the resist A supply time a is about 2 seconds, the time from the end of resist A supply to the start of low speed rotation is about 1 second, and the low speed rotation time C is about 2 seconds, and the high speed rotation time d is about 20 seconds.

Here, when the dropped amount of resist A shown in FIG. 1 is small, resist I-A does not spread over the entire surface of the object to be coated 1 due to the low speed rotation, and for example, as shown in FIG. ) The result will be as shown. This state does not change much even if the time of the low-speed rotation is extended, and even after the high-speed rotation, uncoated portions remain.

Therefore, in this resist coating method, it is necessary to supply a sufficiently large amount of the resist (A), and the amount is extremely large compared to the case where the resist (A) is coated on the surface of the object to be coated. The disadvantage is that the amount of resist A used is large due to scattering.

(d) Object of the Invention In view of the above-mentioned drawbacks of the conventional art, the object of the present invention is to rotate a plate-shaped object to be coated at a predetermined speed parallel to the surface of the object, and apply a resist to the surface to a predetermined thickness. When applying the
It is an object of the present invention to provide a resist coating method that requires less amount of resist.

tel Structure of the Invention The above object is to rotate a flat plate-shaped object to be coated at a predetermined speed parallel to the surface of the object to be coated, and apply a resist to the surface to a predetermined thickness. The resist is supplied to the center of rotation of the surface while rotating at a first speed, the supply is stopped when the resist covers the surface, and the object to be coated is rotated at a second speed faster than the first speed. This is achieved by a resist coating method characterized by rotation at high speed.

This method is based on the knowledge obtained by the inventor of the present application from extensive experience,
In order to obtain the state shown in FIG. 2 (ta) in the embodiment of the conventional method described above, the amount of resist required may be several times smaller than that of the conventional method.

(f) Examples of the Invention Examples of the present invention will be described below with reference to the drawings. The same reference numerals refer to the same objects throughout the design.

6, 7, and 8 are plain views (al) and side views (bl) showing the sequence of one embodiment of the method of applying the resist according to the present invention, and FIG. 9 shows the time course thereof. ←This is a diagram.

The method of resist coating according to the present invention is a knowledge obtained by the inventor of the present application from extensive experience. □ Immediately, as shown in FIG. 6, the object to be coated 1 is placed on the spin head 2 and fixed in the same manner as in the conventional case. 00 rpm). Immediately, as shown in FIG. 7, when the resist A is rotated from the nozzle 3, the resist I-A starts to be supplied under 1+N to the center of rotation of the object 1 to be coated. The supply is stopped when it has spread over the entire surface. Thereafter, as shown in FIG. 8, the object 1 to be coated is rotated at a predetermined high speed (rotation speed S2, for example, about 500 rpm), and the excess resist A is scattered around the object 1 to be coated. The thickness of resist A is set to a predetermined value (for example, about 1 μm).

The time course of the operation of this embodiment is as shown in FIG. 9, starting from the start of low speed rotation, the time C of low speed rotation is about 2 seconds,
The time a for supplying resist A included in that time is about 0.4 seconds, and the time d for high-speed rotation is about 20 seconds. Here, time d
The operation is similar to that of the conventional example, but the time C can be shortened since it is sufficient to finish supplying the register I-A. In addition, since it is difficult in practice to monitor whether resist A has spread over the entire surface of the object 1 to be coated, the dropping onto the resist is controlled by time, and at time a, it is difficult to monitor whether resist A has spread over the entire surface of the object to be coated. Includes allowance for

The inventor of the present application has implemented the resist coating method according to the present invention, and the time C for supplying resist) A, which conventionally required about 2 seconds to reliably coat resist) A with the same standard, has been reduced to only about 2 seconds. It was confirmed that 0.4 seconds was sufficient, and the amount of resist A used was actually reduced to 115 seconds.

(a. Effects of the Invention As explained above, according to the configuration of the present invention, a flat plate-shaped object to be coated is rotated at a predetermined speed parallel to the surface of the object to be coated, and a resist is applied to the surface of the object in a predetermined manner. It is possible to provide a resist coating method that requires less amount of the resist when coating the resist to a thickness of , and has an economical effect of making it possible to significantly reduce the amount of resist used.

[Brief explanation of the drawing]

Figures 1, 2, and 3 are a plan view (a) and a side view (b) showing the order of an example of a conventional method for applying resist.
, FIG. 4 is a diagram showing the time course, FIG. 5 is a diagram showing the state of resist spreading failure, FIGS. 6, 7, and 8.
The figure shows a plan view (al) and a side view (bl) omitting the order of one embodiment of the method of applying a resist according to the present invention, and FIG. 9 is a diagram showing the time course. Coating body, 2 is spin head, 3 is nozzle, A is resist, Sl, S2 are rotation speeds, a, b
Sc and d each indicate time. Hayabusa 4th afternoon 6th drawing 7th edition Hayabusa 9th drawing - I'lL - Darkness

Claims (1)

[Claims] Rotating a plate-shaped object to be coated at a predetermined speed parallel to the surface of the object to be coated and applying a resist to the surface to a predetermined thickness, rotating the object to be coated at a first speed; while supplying the resist to the center of rotation of the surface, stopping the supply when the resist covers the surface, and rotating the object to be coated at a second speed faster than the first speed. Resist coating method.