JPS6242426A - Manufacture of semiconductor device - Google Patents

Abstract

PURPOSE:To form a protective layer easily removable by hot water after machining by a method wherein one main surface side of a semiconductor wafer is coated with the second non-water soluble protective layer through the intermediary of the first water soluble protective film. CONSTITUTION:The surface of a wafer 101 is coated with a water soluble film 1 e.g. polyvinyl alcohol 0.5-1.0mum thick and then the water soluble film 1 is further coated with a non-water soluble film 2 e.g. a resist film 1-10mum thick. Next the side coated with said laminated layers is held by a grinder- lapping machine to grinder-lap the main surface of opposite side down to 250mum thick. After finishing the lapping process, the water soluble film 1 is swelled for lifting off by hot water boiling or hot water ultrasonic washing. Resultantly the non-water soluble film 2 can be removed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a method for manufacturing a semiconductor device, and particularly to protection of a main surface in a process of applying a grinder wrap to a semiconductor wafer (hereinafter abbreviated as wafer).

[Technical background of the invention]

In the manufacturing of semiconductor devices, for example, IC chips are often made thin to reduce discrete current, improve heat dissipation to reduce thermal resistance, and also to facilitate dicing from wafers. It tends to be used.

On the other hand, processing, processing, and handling such as diffusing impurities into a wafer or forming and removing a mask for this purpose requires a considerable thickness to prevent cracking of the wafer. Also,
Some methods use diodes or the like to perform diffusion on both sides of a thick wafer, then remove one diffusion layer and use only the other diffusion layer.

The reduction in the thickness of the wafer described above is achieved by grinder lapping (Gr
inter wrapping). In this grinder lap, the wafer is fixed on a vacuum chuck table and a grindstone rotating at high speed is applied to the wafer to grind it. If the wafer surface is directly adsorbed and fixed on the chuck table for grinding, scratches and dirt will occur on the wafer surface due to scratches (protrusions) on the table surface, grinding debris, etc. This was done either by painting it on the table surface or by pasting adhesive tape on the surface so that the surface would stick to the table surface. After the wafer has been thinned, it is removed with a resist remover, and then the wafer is cut to form element chips.

The steps described above are shown in Figures 2a-C. In figure a, lo
t is a part of the wafer, including electrodes of multiple semiconductor elements, electrical insulating layers (SiO□ layer), etc. 101a, 1.0], a...
・ is formed on the surface. Note that illustration of the diffusion layer and the like in each semiconductor element is omitted. In addition, 102 is a resist film (for example, 2 to 10 μm thick) deposited on the surface.
For example, the product name is OMR-83 (manufactured by Tokyo Ohka Kogyo KK). Next, the front surface was suctioned and fixed to a vacuum chuck table, and the back surface was ground to a thickness of 250 μm. next,
The resist film 102 is washed and removed with a resist stripping solution (for example, OMR Stripping Solution 602 (trade name, manufactured by Tokyo Ohka Kogyo Co., Ltd.) or an organic chlorine solvent, etc., to obtain a thinned semiconductor element as shown in Figure C. It will be done.

[Problems with background technology]

The conventional protective films such as resists and adhesive tapes used to protect the surface when applying the grinder lamp have the problem of requiring expensive chemicals to be removed after the grinder lapping process is completed. In addition, this chemical, like organic chlorine solvents, is undesirable from the standpoint of safety, hygiene, and pollution.

[Purpose of the invention]

In view of the above conventional problems, the present invention improves a method for protecting one main surface of a wafer during processing of the other main surface in the manufacture of semiconductor devices.

[Summary of the invention]

A method for manufacturing a semiconductor device according to the present invention includes depositing a water-soluble first protective layer on one main surface of a semiconductor wafer and a water-insoluble second protective layer laminated thereon. After the wafer is held and the other main surface is processed, the first protective layer is removed by dissolution with hot water, and at this time, the second protective layer is also floatingly removed.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to FIG. In addition, in the description, parts that are the same as those in the prior art are indicated by the same reference numerals as in the prior art in the drawings, and the description thereof will be omitted.

A water-soluble film 11, such as a polyvinyl alcohol film, is applied to a thickness of 0.5 to 1.0 μm on the surface of the wafer 101, which has undergone diffusion and surface electrode formation. This film 1
For example, the polyvinyl alcohol film of Kuraray Bovar (
(trade name, manufactured by Kuraray Co., Ltd.) was deposited by a spin cord method at 200 ORPM for 20 seconds.

Next, the film 1 is laminated with a water-insoluble film 21, such as a resist film, to a thickness of 1 to 10 μm. The resist film of this film 2 is, for example, OMR-83 (
Product name: Manufactured by Tokyo Ohka Kogyo Co., Ltd. 20 at 170 ORPM
After coating with a second spin cord, it is baked at 90° C. for 10 minutes to form a thickness of 1 to 10 μm, for example, 5 μm (Figure a).

Next, the main surface (surface) on the side to which the above laminated layer has been applied is processed using a grinder-lap device, for example, DFG-83H/6 (trade name, manufactured by DISCO Co., Ltd.). Hold the surface (front surface) and apply grinder wrap to the opposite main surface (back surface) to a thickness of, for example, 250 μm (Figure b).

Next, by removing the water-soluble film 1 from the water, the water-insoluble film 2 is also floated and removed. For this purpose, shake in warm water at 70°C or perform ultrasonic cleaning with warm water for 10 minutes, then rinse with running water for 5 minutes, and then
This is achieved by spin drying (Figure C).

〔Effect of the invention〕

According to the method of this invention, since the surface protective film has a laminated structure and the first layer on the wafer surface side is a water-soluble film, the water-soluble film can be swollen only by hot water boiling or hot water ultrasonic cleaning. By peeling off, the water-insoluble film can also be removed. Note that water permeation into the water-soluble film is achieved through the end faces of the film or through fine pores present in the water-insoluble film.

As mentioned above, the method of this invention is easy, does not require any expensive chemicals, and has significant advantages such as no safety concerns.

[Brief explanation of the drawing]

Figure 1 a''Q shows a method for manufacturing a semiconductor device according to the present invention in the order of steps. Both are cross-sectional views of a part of a wafer. Figure 2 a'=c shows a conventional method for manufacturing a semiconductor device in order of steps FIG. 3 is a cross-sectional view of a portion of the wafer.

Claims (2)

[Claims] (1) A water-soluble first protective layer is deposited on one main surface of a semiconductor wafer, and a water-insoluble second protective layer is laminated thereon,
A method for manufacturing a semiconductor device, which includes a step of holding a wafer on this main surface and processing the other main surface, removing the first protective layer by dissolving it in hot water, and at the same time, floatingly removing the second protective layer as well. (2) A method for manufacturing a semiconductor device, characterized in that the aqueous removal according to claim 1 is performed by applying ultrasonic waves.