JPH05335207A - Exposure method and stepper - Google Patents

Abstract

PURPOSE:To obtain a stepper wherein, in a transfer opration in a step-and-repeat manner, it is possible to restrain that a resist is bubbled at a wafer stage part on the resist on the surface of a wafer whose periphery has been exposed in advance. CONSTITUTION:A light-shielding member 6 which shields an edge part on a wafer 2 from exposure light is installed on the wafer mounting face of a stage 3 which is moved two-dimensionally, in which the wafer 2 is mounted on its surface and which is moved in a definite size in a step-and-repeat operation.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a step-and-repeat exposure method for printing a predetermined pattern on a resist on a wafer and a reduction projection exposure apparatus.

[0002]

2. Description of the Related Art FIG. 2 is a schematic sectional view showing a structure of a main part of a conventional reduction projection exposure apparatus. In the figure, 1 is a reduction lens, 2 is a wafer having a resist film formed on its upper surface, 3 is a wafer.
Is a stage that can be moved in two dimensions, 4 is a reticle, and 5 is a light source.

Next, the operation will be described. First, the wafer 2 is vacuum chucked by a vacuum mechanism (not shown) on the stage 3 which can be moved two-dimensionally. Then, the stage 3 is moved in a fixed size, and the exposure light from the light source 5 is irradiated to the resist on the upper surface of the wafer 2 through the reticle 4 on which a predetermined pattern is drawn, every time the fixed size is moved. The pattern drawn on the reticle 4 is transferred to the resist on the upper surface of the wafer 2 by and repeat to obtain a transfer pattern having excellent resolution.

By the way, normally, the wafer 2 used for this transfer work does not generate resist scraps or dust from a portion which holds the wafer during a wafer process such as an etching work later, that is, an edge portion of the wafer 2. As described above, during development after the transfer operation, a portion corresponding to the wafer edge portion of the resist is predetermined so that the resist on the edge portion of the wafer 2 is removed similarly to the pattern exposure portion exposed by the transfer operation. The amount of exposure has been exposed.

[0005]

The conventional reduction projection exposure apparatus is constructed as described above, and resist scraps and dust are not generated from a portion which is gripped at the time of working in a later wafer process, that is, a wafer edge portion. The wafer, on which the resist of the portion corresponding to the wafer edge is previously exposed, is chucked on the stage 3, and the pattern drawn on the reticle 4 is transferred to the resist on the wafer 2 by step and repeat.

However, in such step-and-repeat exposure, the resist on the wafer 2 is exposed every time the stage 3 moves by a fixed size. Therefore, before the step-and-repeat exposure,
The exposed portion of the resist corresponding to the wafer edge is overexposed (excessive exposure amount), the resist in this portion foams, and as a result, the resist in the vicinity is distorted, or other There is a problem that the dimensional accuracy and the resolution of the transfer pattern are deteriorated by depositing the resist foam on the area (1).

The present invention has been made to solve the above problems, and when transferring the pattern drawn on the reticle to the resist on the wafer by step-and-repeat, the resist on the edge portion of the wafer exposed to the periphery is exposed. It is an object of the present invention to obtain an exposure method and a reduction projection exposure apparatus capable of suppressing the bubbling of the.

[0008]

In the exposure method according to the present invention, the resist in the portion corresponding to the wafer edge is shielded from light while the pattern transfer is performed by step and repeat. In the reduction projection exposure apparatus according to the present invention, a stage for chucking the wafer on its upper surface and feeding it at a fixed size is provided with a light blocking member for blocking the edge portion of the chucked wafer.

[0009]

In the present invention, the resist of the portion corresponding to the wafer edge is prevented from being exposed while the pattern transfer is performed by the step and repeat.
Even if a wafer that has been subjected to peripheral exposure (exposure of the wafer edge portion) in advance is used, the wafer edge portion is not overexposed, and it is possible to suppress the bubbling of the resist in this portion.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. 1A and 1B are diagrams schematically showing a stage for vacuum-adsorbing a wafer of a reduction projection exposure apparatus according to an embodiment of the present invention. FIG. 1A is its sectional view and FIG. 1B is its top surface. It is a figure. In the figure, the same reference numerals as those in FIG. 2 indicate the same or corresponding portions, and 6 is a light-shielding member, and is composed of a support portion 6a fixed to the stage 3 and an eaves portion 6b for covering the edge portion of the wafer 2 from above. It is configured. A light source, a reticle, and a reduction lens similar to the conventional one shown in FIG. 2 are arranged around the stage.

The operation will be described below. A portion of the resist corresponding to the wafer edge portion is exposed by a predetermined exposure amount, and the wafer 2 provided with the resist on its upper surface is chucked by a vacuum mechanism (not shown) on a stage 3 which can be moved two-dimensionally. Then, the stage 3 is moved by a fixed dimension, and every time the fixed dimension is moved, exposure light from a light source (not shown) is transmitted through a reticle on which a predetermined pattern (not shown) is drawn to the resist on the upper surface of the wafer 2. To do. Here, since the light emitted from the light source to the edge portion of the wafer 2 does not reach the resist on the upper surface of the wafer 2 by the light shielding member 6, the resist in this portion does not become overexposed and the foaming of the resist is suppressed. To be done. Thereafter, the wafer 2 having the pattern drawn on the reticle transferred to the resist is subjected to a development process, and at the time of this exposure, the pattern-exposed portion and the resist of the edge portion of the wafer 2 which has been previously exposed are removed. .

In the reduction projection exposure apparatus of this embodiment as described above, the edge portion of the wafer 2 is shielded from the exposure light while the wafer 2 is mounted on the stage 3 which mounts the wafer 2 and feeds it at a constant size. Since the light shielding member 6 is provided, when the pattern drawn on the reticle by step and repeat is transferred to the resist on the upper surface of the wafer 2, the exposure light is not applied to the resist on the edge portion of the wafer 2. Even if the resist of the wafer 2 is a resist which has been subjected to the peripheral exposure (the resist portion corresponding to the edge portion of the wafer is exposed) in advance, the edge portion of the wafer 2 may be exposed during the exposure operation by the step and repeat. The resist of the corresponding part can be prevented from foaming due to overexposure, and the transfer pattern obtained after development has excellent dimensional accuracy and resolution. The things.

Although the light shielding member 6 is fixed to the stage 3 in the above embodiment, the light shielding member is not necessarily the stage 3.
However, for example, a plate-shaped member that moves in synchronization with the stage 3 and that has a circular opening through which the exposure light passes may be provided.

[0014]

As described above, according to the present invention, the resist of the portion corresponding to the wafer edge is shielded from light while the pattern transfer is performed by the step and repeat. Therefore, before the pattern transfer by the step and repeat is performed. Even if a wafer that has been subjected to peripheral exposure in advance is used, the resist in the portion corresponding to the edge portion of the wafer does not overexpose, and foaming of the resist in this portion can be suppressed. There is an effect that a transfer pattern having excellent image quality can be formed.

[Brief description of drawings]

1A and 1B are diagrams schematically showing a stage on which a wafer of a reduction projection exposure apparatus according to an embodiment of the present invention is mounted. FIG. 1A is a sectional view thereof, and FIG. It is a top view.

FIG. 2 is a schematic cross-sectional view showing the configuration of a conventional reduction projection exposure apparatus.

[Explanation of symbols]

 1 Reduction Lens 2 Wafer 3 Stage 4 Reticle 5 Light Source 6 Light-shielding Member 6a Supporting Part 6b Eaves Part

Claims (2)

[Claims] 1. A portion of a resist formed on the upper surface of a wafer corresponding to the wafer edge is exposed with a predetermined exposure amount,
After that, in the exposure method of transferring the pattern drawn on the reticle to the resist by step-and-repeat in which the wafer is sized and fed, and the resist is exposed each time the dimensional-feed is performed. An exposure method, characterized in that the resist in the portion corresponding to the wafer edge is shielded from light during the pattern transfer by the repeat. 2. A wafer which has a resist film formed on its upper surface is vacuum-chucked on a stage which can be moved two-dimensionally, and the stage is moved to feed the wafer at a fixed size. A reduction projection exposure apparatus that exposes the resist each time it is sent, wherein the stage is provided with a light shielding member that shields the edge portion of the vacuum chucked wafer.