JPS62128121A - Manufacture of semiconductor device - Google Patents

Abstract

PURPOSE:To decrease the amount of wastes and to improve the yield and the quality of products, by forming a resist film pattern such that no resist film is provided on the periphery of a wafer, and subjecting the wafer to various treatments such as etching or the like while protecting it with the resist film. CONSTITUTION:A wafer 10 is conveyed from a casette 11 to a loading stage 13. A light beam with a diameter of 10mm is applied along the periphery of the wafer arranged on the loading stage 13 while the stage 13 is being rotated, so that the peripheral region of the wafer with a width of about 10mm is exposed. The applied light beam is conducted through an optical fiber 16 from a light source 12L of a stepper 12. The wafer is then conveyed to an exposing stage 14 where it is exposed for the formation of a pattern by the stepper 12. The wafer is developed in the next state and thus is provided with a resist film pattern 20. According to this method, the resist film will not be peeled off if the periphery of the wafer is contacted with various devices and consequently possible wastes can be decreased.

Description

DETAILED DESCRIPTION OF THE INVENTION [Summary] In a photo process, when forming a resist film pattern, the resist film at the periphery of a semiconductor wafer is removed, and the resist film pattern is used as a protective film for etching or other processing. This will reduce the amount of waste generated during processing.

[Industrial Field of Application] The present invention relates to a method for manufacturing a semiconductor device, and in particular to a photo process for semiconductor wafers.

The wafer process for semiconductor devices includes the so-called photo process, in which fine patterns are formed using photolithography, and this photo process is an important process that has a fatal impact on the quality and yield of semiconductor devices such as ICs. be.

Therefore, the adhesion of dust and dirt during the photo process must be avoided as much as possible.

[Previously, the problems that conventional techniques and inventions try to solve
In the photo process, a resist film is applied to the surface of a semiconductor wafer (hereinafter abbreviated as wafer), and a photomask of the same size (having the same size as the wafer and
A method is used in which a resist film pattern is formed on the entire surface of the wafer at once by exposing the wafer to light (a mask with a pattern of the same size), and this resist film pattern is used as a protective film to process the wafer such as etching. Ta.

However, recently, a reduction projection exposure device (stepper) is used to repeatedly expose the resist film on the wafer surface while moving the wafer position with a reticle (a mask with a 5 to 10 times enlarged pattern). A so-called step-and-repeat reduction projection exposure method is widely used, and a method is adopted in which a resist film pattern created in this way is used as a protective film to process a wafer.

This is because the reduction projection exposure method is more suitable for forming fine patterns, and advances in optical systems have made such reduction projection exposure methods possible.

On the other hand, in the past, resists were mainly negative type, but recently, due to the use of reduction projection exposure equipment, which generally exposes at G-line and I-line wavelengths, positive type resists have been used. Positive resists are commonly used because of their high resolution and are suitable for forming fine patterns.

That is, the mainstay of recent photoprocessing is a method of forming a positive resist film pattern by a reduction projection exposure method.

However, the mainstream of positive resists is novolac type phenolic resin, which is mechanically weak and has the disadvantage of being prone to peeling and cracking. In particular, since positive resists have exposed areas that are dissolved during development, the periphery of the wafer that is not patterned (the periphery is easily damaged during handling, so almost no elements are formed on it).
Unexposed resist films often remain as they are. Then, during the subsequent etching process, the remaining resist film on the periphery becomes rubbed by friction during transport of the wafer to the processing equipment and becomes dust, which adheres to the wafer surface. Decreases yield and quality.

FIG. 4 is a diagram showing this, where (al and (bl) are a plan view and a cross-sectional view of a wafer on which a conventional positive resist film pattern is formed, 1 is the wafer, and 2 is the resist film pattern. Note that the cross-sectional view in Figure (b) shows the AA' cross section of the plan view in Figure (al).As shown in the figure, if the resist film is coated to the peripheral edge of the wafer, it may come into contact with the processing equipment. The resist film on the wafer periphery S, which tends to peel off, becomes dust.

The present invention proposes a processing method for eliminating such dust that has an adverse effect on yield and quality.

[Means for solving the problem] The purpose is to form a resist film pattern by removing the resist film at the peripheral edge of a semiconductor wafer, and to process a semiconductor using the resist film pattern as a protective film. The problem is solved by a method of manufacturing the device.

[In other words, the present invention removes the resist film at the periphery of the semiconductor wafer, and forms a resist film pattern in the central part,
The wafer surface is processed using the resist film pattern as a protective film. This will greatly reduce waste generation.

[Example code] Hereinafter, embodiments will be described in detail with reference to the drawings.

FIGS. 1A and 1B show a plan view and a cross-sectional view of a wafer on which a positive resist film pattern according to the present invention is formed, where 1 is the wafer and 20 is the resist film pattern. The cross-sectional view in Figure (b) shows the BB' cross-section in the plan view of Figure (al).In this way, if a resist film pattern is formed with the resist film at the wafer peripheral area removed, it is possible to Even if the peripheral edges of the wafers come into contact, the resist film will not peel off and the generation of dust will be reduced.

FIG. 2 shows an example of the method for forming the same, and this example is a schematic diagram of an automatic stepper. In the figure, 1)゜1)' is a cassette containing a wafer 10 (a wafer coated with a resist film), 12 is a stepper, 13 is a load stage, 14 is an exposure processing stage, 15 is an unload stage, and the stepper is A light source 12L, a reticle 12R2 and a reduction lens 12E are provided. Further, the wafer 10 is structured to be automatically moved and transported on a stage by a transport system (not shown), such as an air chute.

With this device, when performing exposure processing, conventionally the cassette 1
), the wafer 10 is transferred to the load stage 3, then placed on the exposure processing stage 14 at the bottom of the stepper 12, and the processing stage 14 is operated in the X and Y directions to perform exposure in a step-and-repeat manner. It was stored in a cassette 1)' through the load stage 15.

In addition, the forming method according to the present invention provides that the cassette 1
), and when the wafer 10 is transferred to the load stage 13 and placed on the load stage 13, the peripheral edge of the wafer is irradiated with light having a diameter of 10 fins, and the load stage 13 on which the wafer 10 is placed is rotated. In this way, the peripheral edge of the wafer is exposed in a band shape with a width of about 10 m. Further, the irradiation light is led out from the light source 12L of the stepper 12 through the optical fiber 16.

In this manner, the peripheral edge of the wafer 10 is exposed in advance, and then the wafer 10 is transported to the exposure processing stage 14 and exposed to form a pattern using the stepper 12. Thereafter, when the next development process is completed, a wafer on which a resist film pattern 20 shown in FIG. 1 is formed is obtained.

As another method for forming the resist film pattern 20 on the wafer 1, as shown in FIG.
7 may be placed and rotated to dissolve and remove the resist film at the peripheral edge. In this way, it is not very difficult to automate the method of removing the resist film at the peripheral edge by dissolving it in a solvent.

If a resist film pattern is formed by removing the resist film at the periphery of the wafer as described above, and the resist film pattern is used as a protective film for processing such as etching the wafer, the generation of dust will be reduced. Yield and quality are improved.

[Effects of the Invention] As is clear from the above description, the manufacturing method according to the present invention is significantly useful for improving the yield and quality of semiconductor devices such as ICs.

[Brief explanation of drawings]

FIGS. 1(a) and (b) are a plan view and a cross-sectional view of a wafer on which a resist film pattern according to the present invention is formed, FIGS. 2 and 3 are diagrams showing the method of forming the same, and FIG. 4(a) and (b) are a plan view and a cross-sectional view of a wafer on which a conventional resist film pattern is formed. In the figure, 1.10 is a wafer, 2.20 is a resist film pattern 1). 1)' is a cassette, 12 is a stepper, 13 is a load stage, 14 is an exposure processing stage, 15 is an unload stage, 12L is a light source, 12R is a reticle, 12E is a reduction lens, 16 is an optical fiber, 17 is a roller, I and F3 ear l; Kakashi 3 and jizut I4 lead mask-η is 58゛ and R ke illusion\
- Fig. 1 Half nago θI + 1 = 51 ・■ Zl - Membrane 07 - Shigari bandit ゛ Shiba stand q Fig. 2 @
4 Figure 3

Claims (3)

[Claims] (1) A method for manufacturing a semiconductor device, characterized in that a resist film pattern is formed by removing the resist film at the peripheral edge of a semiconductor wafer, and the resist film pattern is used as a protective film for processing. (2) The peripheral edge of the positive resist film coated on the semiconductor wafer is exposed and developed to remove the positive resist film.
A method for manufacturing a semiconductor device according to section 1. (3) The semiconductor according to claim 1, wherein the peripheral edge of the positive resist film coated on the semiconductor wafer is dissolved in a resist solvent to remove the positive resist film. Method of manufacturing the device.