JPS59138336A - Method for exposing pattern on semiconductor wafer - Google Patents

Abstract

PURPOSE:To facilitate detachment of a mask from a wafer without using an attraction inhibitor by concentrating the force for pressing the mask on a wafer surface locally by deforming the wafer so as to show a swelling figure in its cross sectional view. CONSTITUTION:A projection 13 is formed in center of a top 10a of a vacuum chuck 10. At first, the chuck 10 is reduced the pressure inside of it in advance and attracts a semiconductor wafer 11 on which a resist film 14 is formed, on the top 10a. At this time, the wafer 11a bends as it swells toward the film 14 and near the projection 13 under the wafer 11a, a space 15 is formed. Next, a photo mask 16 is placed on the film 14 and is pressed against it. Under this condition, exposure treatment is made for the wafer 11 through the mask 16. Next, the pressing force which has been applied to the mask 16 is released. When the pressing force is released, a space 17 is generated between the mask 16 and the circumferential portion of the film 14. As the air comes into through this space 17, the mask 16 can be detached from the film 14 easily.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a method of pattern exposure on a semiconductor wafer.

[Technical background of the invention]

Conventionally, a pattern exposure method as shown in FIG. 1 has been used to form a resist film or the like in a desired pattern on the surface of a semiconductor wafer. First, a resist film is applied on the surface in advance.
The semiconductor wafer 2 on which is formed is suctioned and fixed onto the vacuum chuck 3.

Next, a photomask 4 having a predetermined pattern is placed on the resist film 1. Using this photomask 4 as a mask, ultraviolet rays are irradiated to expose the resist film 1 in a pattern. In the case where pattern exposure is performed in this way, Fig. 2 (5)
As shown in FIG. 3B, the semiconductor wafer 2 is placed on the flat surface of the top of the vacuum chuck 3 and pattern exposure is performed, which causes the following problems.

[Problems with background technology]

■ Since the photomask 4 and the semiconductor wafer 2 are in close contact with each other over the entire surface through the resist film I, when one ray of ultraviolet light is applied, the resist film 1 and the lower surface of the photomask 4 are chemically and physically adsorbed. , the photomask 4 cannot be easily peeled off from the semiconductor wafer 2.

■ In order to facilitate the removal operation of the photomask 4, an anti-adsorption agent is applied to the surface of the resist film I and the bottom surface of the photomask 4, but as the number of steps increases, it is difficult to apply the anti-adsorption agent uniformly. Difficult to apply due to thickness.

[Object of the Invention] The present invention provides pattern exposure for semiconductor wafers that facilitates separation of the wafer and mask without applying an anti-adsorption agent to the surface of the wafer or mask, thereby improving workability and economic efficiency. It's a method.

[Summary of the invention]

The present invention deforms the wafer into a convex cross-section so that the force when pressing the mask is partially concentrated on the wafer surface, making it easy to separate the wafer and mask without using an anti-adsorption agent. This is a pattern exposure method for semiconductor wafers that has improved workability and economical efficiency.

[Embodiments of the invention]

Embodiments of the present invention will be described below with reference to the drawings.

First, a vacuum chuck 10 as shown in FIG. 3 (5) and FIG. 3 (to) is prepared. This vacuum chuck 1° has a suction hole 12 for fixing a semiconductor wafer 11 at the top 10a.
We have many of them. In the center of the top 10a,
A convex portion 13 is formed. The convex portion 13 curves the semiconductor wafer 11 fixed onto the vacuum chuck 10 into a convex shape. If it has this effect, the convex portion 13
The position, size, and height of can be set as desired. - For example, the top 10a with a diameter of 110 mm
A convex portion Z3 having a diameter of 10 m111φ and a height of about 10 μm may be formed at the center of the plate.

Next, as shown in FIG. 4 (N), the interior of the vacuum chuck 10 is previously set to a reduced pressure state, and the semiconductor wafer 11 with the resist film 14 formed on its surface is suctioned and fixed onto the top portion 10a.At this time, the semiconductor wafer 11 is curved in a convex shape toward the resist film 14 side, and a gap 15 is formed near the convex portion z3 on the lower surface thereof.

Next, as shown in FIG. 11
The resist film Z4 is adhered to the top through the resist film Z4, sometimes receiving a strong adhesive force at the center thereof. In this state, the semiconductor wafer 11 is exposed to ultraviolet light of a predetermined wavelength through the photomask 16.

Next, after the exposure process, as shown in FIG. A gap 17 is created between Z4 and the photomask 16. Air enters through this gap Z7,
The photomask 16 can be easily peeled off from the resist film 14. Moreover, since no anti-adhesion agent is applied to the adhesion surfaces of the photomask 16 and the resist film I4, workability can be improved by the time required for the application process. Moreover, it is possible to eliminate the need for an anti-adhesive agent, thereby improving economical efficiency. .

Incidentally, according to the method of the present invention, work efficiency can be reduced by about 3 minutes compared to the conventional method. Further, although all of the photomasks 16 could be easily peeled off after pattern exposure, it was experimentally confirmed that 25% of the photomask I6 could not be completely peeled off using the conventional method.

〔Effect of the invention〕

As explained above, according to the semiconductor wafer pattern exposure method according to the present invention, the wafer and mask can be easily separated without applying an anti-adsorption agent to the surface of the wafer or mask, thereby improving workability and economy. It has remarkable effects such as being able to improve performance.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram showing a state in which pattern exposure of a resist film is performed using a conventional method, and FIG. 2 (8 is a plan view of a vacuum chuck used in the conventional method; Figure 3 (5) is a cross-sectional view of the vacuum chuck, and Figure 3 (5) is a plan view of the vacuum chamber used in the method of the present invention. Figure (q is an explanatory diagram showing the method of the present invention in the order of steps. 10... Vacuum chuck, 10a... Top, lI...
- Semiconductor wafer, 12... suction hole, 13... convex part,
14...Resist film, I5...Gap, 16...Photomask, 17...Gap. Applicant's agent Patent attorney Takehiko Suzue Figure 1 Figure 2

Claims (1)

[Claims] a step of forming a resist film on a surface of a semiconductor wafer; a step of placing a photomask on the resist film after deforming the semiconductor wafer into a convex shape toward the surface on which the resist film is formed; and a step of placing a photomask on the resist film; A method for pattern exposure on a semiconductor wafer, comprising the step of subjecting the resist film to exposure using a mask.