JPS63237408A - Substrate for semiconductor device - Google Patents

Abstract

PURPOSE:To enhance the quality and yield rate of a product by a method where in a groove along a cutting pattern is made in advance at a silicon single-crystal thin film of an SOI substrate so that the thin film can be cut without damage. CONSTITUTION:A resist 6 is coated on the surface of a mainly formed SiO2 film 5; after that, a desired cutting pattern whose width W is almost 100 microns is exposed and processed; the SiO2 film 5 is etched by using a buffer solution of hydrofluoric acid; grooves 7a are made. Then, this assembly is etched in an aqueous solution of KOH; an SiO2 film of a substrate is bonded to a face where the resist 6 and grooves 7 have been formed. Lastly, if the rear of the grooves 7 is ground to form a silicon single-crystal thin film 4a whose thickness is less than 5 mu, an SOI substrate 1 where the grooves of a desired pattern have been made is obtained. When the SOI substrate manufactured in this way is cut along the grooves 7, no chipping occurs and a good cut piece is obtained.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a substrate for semiconductor devices.

[Conventional technology and problems to be solved]

Conventionally, as a method for manufacturing semiconductor devices, SOI (Sen+1-condu), in which a thin film of silicon single crystal is bonded to a holding substrate via a silicon oxide film, is used.
There is a method in which a large number of electric circuits are formed on a single crystal thin film of a substrate and then cut into several angles. When the substrate 1 is cut with a dicing saw using the rotary blade 3, if so-called chipping occurs, which causes defects in the silicon single crystal thin film 2 as shown in FIG. There were problems that caused it to malfunction or become inoperable.

[Means and operations for solving the problems] In order to solve the above-mentioned problems, the present invention is such that grooves are formed in advance along the cutting pattern in the silicon single crystal thin film of the SOI substrate. If the depth of the wire groove is greater than the thickness of the thin film and its width is greater than the thickness of the cutting machine's blade, the thin film will not be damaged during cutting.
Therefore, malfunctions due to chipping do not occur in the electric circuit. In addition, the holding substrate and the thin film are separated by an oxide film, and the bonding force between each layer is weaker than the bonding force in silicon itself, so even if a defect occurs in the holding substrate during cutting, it will not propagate to the silicon thin film. There is no.

[Example (1)] An example of the SOI substrate of the present invention will be described with reference to the drawings.

FIG. 1 is a plan view of the 501 substrate of the present invention, and FIG.
9 to E are diagrams showing manufacturing steps. As shown in FIG. 2A, a silicon single crystal substrate 4 is heated in air to form a 5in2 film 5 with a thickness of about 1500 Å on its surface. Next, a resist 6 is applied to the surface of the generated SiO□ film 5, and then a desired cutting pattern with a width W of about 100 microns as shown in Fig. 1 is exposed to light, and the SiO□ film 5 is etched with a buffered acid solution. Then, grooves 7a are formed as shown in Figure B. Next, by etching in a KOH aqueous solution, the resist 6 and the exposed portion of the substrate 4 are removed to a depth of about 5 μm to form a groove 7, as shown in FIG. Next, the SiO□ film of the same substrate as in Fig. A is bonded onto the surface on which the groove 7 is formed as shown in Fig. D. Finally, as shown in Fig. E, the surface on the back side of the grooves 7 is polished to form a silicon single crystal thin film 4a having a thickness of 5 μm or less, thereby obtaining a SOIG plate 1 having grooves 7 in a desired pattern.

When the SO1 substrate manufactured in this way was cut with a cutting tool along the groove 7, no chipping occurred and a good cut piece was obtained.

[Embodiment (2)] Another embodiment will be described with reference to FIG. First, as shown in Figure A, a SiO□ film 5 is formed on the surface using the same method as in Example +1).
Two silicon single-crystal substrates 4 on which are formed are prepared.

Next, as shown in Figure B, the SiO□ film surfaces of the two substrates are bonded. Then, one single crystal substrate 4 is formed into an fH1i with a thickness of 5μ or less.
Polish until it reaches 4a. After that, a first
Pattern the desired cutting pattern as shown in the figure,
Dry etching with CF, gas, etc. to create grooves 7 as shown in figure D.
A 501 substrate l was obtained.

When the 501 substrate 1 manufactured in this manner was cut with a cutting tool along the groove, no chipping occurred at all, and a good cut piece was obtained.

〔Effect of the invention〕

As explained above, in this invention, grooves are formed in advance along the cutting pattern in the silicon single crystal thin film of the SO■ substrate.
By cutting along this groove, the thin film can be cut without damaging it. Therefore, when this SOI substrate is used and an electric circuit is formed on the thin film to manufacture a semiconductor device, device defects due to chipping do not occur during cutting, resulting in extremely significant improvements in product quality and yield. I can be hatched.

[Brief explanation of the drawing]

Fig. 1 is a plan view of the So1 substrate of the present invention, and Fig. 2.3 is a plan view of the So1 substrate of the present invention.
The figure shows the manufacturing process of the SO1 substrate of the present invention, and FIG. 4 shows the cutting situation. DESCRIPTION OF SYMBOLS 1... So1 substrate, 2,4a... Silicon single crystal thin film, 4... Silicon single crystal substrate, 5... Silicon oxide film, 7.7a... Groove. Patent applicant Sumitomo Metal Mining Co., Ltd. Figure 1 Figure 4

Claims (1)

[Claims] 1. A substrate for a semiconductor device, characterized in that, in an SOI substrate in which a thin film of silicon single crystal is bonded to a holding substrate via a silicon oxide film, a groove is provided on the silicon single crystal side along a cutting pattern of the substrate.