JPH02184026A - Method of forming semiconductor device - Google Patents

Abstract

PURPOSE:To make it hard to cause cracks at a place where an isolating and diffusion part is formed by forming a plurality of grooves or holes at one surface of the place, where the isolating and diffusion part of a semiconductor substrate is formed, and forming a plurality of grooves or holes at the other surface alternately to the said grooves or holes, and then forming an isolating and diffusion part. CONSTITUTION:A plurality of grooves (or holes) 31a and 31b are formed by etching at the upper face of the place to form the isolating and diffusion part of a semiconductor substrate 1. Also, at the lower face too are formed a plurality of grooves (holes) 32a-32c by etching. And the grooves 32a, 32b, and 32c are formed so that the part between the grooves 32a and 32b may be opposed to the groove 31a, and that the part between the grooves 32b and 32c may be opposed to the groove 31b. Hereafter, an isolating and diffusion part 4 is formed at the part where these grooves 31a, 31b, and 32a to 32c are formed.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a method for forming a semiconductor device, and more particularly to a method for forming a semiconductor device such as a Brehner-type SIRISK or TRIAC that requires separation and diffusion.

<Prior Art> Hereinafter, the conventional technology will be explained with reference to FIG. 2, taking as an example a method of forming a cyrisk.

FIG. 2 is a diagram for explaining the conventional method of forming a thyristor, and FIG. 2(a) is a cross-sectional view of a state in which separation and diffusion have been performed on a substrate, and FIG. FIG. 3 is an explanatory cross-sectional view of a state in which the cyrisk is formed and then divided into chips.

When manufacturing a Brainer-type thyrisk, after forming separation diffusion parts on a substrate, a thyristor is formed between the separation diffusion parts, and a chip-shaped thyrisk is obtained by cutting approximately the center of the separation diffusion part.

As the size of the wafer becomes larger, the thickness of the semiconductor substrate becomes larger, so it takes a longer time to form the separation diffusion section. Therefore, in order to shorten this time, a groove is previously formed by etching at the location where the isolation/diffusion section is to be formed to reduce the thickness of this location, and then the isolation/diffusion section is formed at this location.

That is, as shown in FIG. 2(a), an N-type semiconductor substrate 1
Opposite grooves 3 are formed by etching on both sides of the area where the isolation diffusion part is to be formed to reduce the thickness of this area, and a high concentration P-type impurity is diffused from both sides of this area. A separation/diffusion section 4 is formed. After this,
As shown in FIG. 2(b), a P'' layer 11 is formed as an anode section on the lower surface of the N-type semiconductor substrate 1 between the isolation diffusion sections 4, and a 24 layer 12 is formed as a gate section on the upper surface. After forming the N° layer 13 as a cathode part on a part of the layer 12, an anode electrode 15, a gate electrode 16, and a cathode electrode 17 are formed in contact with the P+ layer 11, the 23 layer 12, and the N′ layer 13, respectively. Then, a thyristor chip is obtained by cutting approximately the central part of the isolation diffusion part 4 by a dicing method.Note that 2 is an oxide film, and 10 is an N layer that originally constituted the semiconductor substrate 1. .

<Problems to be Solved by the Invention> However, in the semiconductor device shown in FIG. 2(a), grooves 3 are provided at opposing locations on both sides of the semiconductor substrate 1, and the thickness of these locations is reduced. However, there was a drawback that cracks were likely to occur at this location.

The present invention has been devised in view of the above circumstances, and provides a method for forming a semiconductor device that can form an isolation/diffusion section in a short time and is less prone to cracking at the location where the isolation/diffusion section is formed. It is intended to.

<Means for Solving the Problems> In order to solve the above-mentioned problems, a method for forming a semiconductor device according to the present invention includes a method for forming a semiconductor device in which an isolation diffusion portion is formed at a predetermined location of a semiconductor substrate. After forming a plurality of grooves or holes on one surface and forming a plurality of grooves or holes arranged alternately with the grooves or holes on the other surface, the separation diffusion section is formed.

<Operation> A plurality of grooves or holes are formed on one surface of a predetermined location of a semiconductor substrate, and a plurality of grooves or holes arranged alternately with the grooves or holes are formed on the other surface, and then an isolation diffusion section is formed. Form. Therefore, even if the semiconductor substrate is thick, the time required for separation and diffusion is short, and the semiconductor substrate is difficult to break.

<Example> Hereinafter, one embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a cross-sectional explanatory diagram for explaining one embodiment of the present invention, in which FIG. 1(a) shows a state in which grooves or holes are formed in a semiconductor substrate, and FIG. 1(Φ) shows a separated diffusion state. The state where the part is formed,
Figure 1 (C) shows the state in which Cyrisk is formed, Figure 1 (d)
) indicates the state divided into chips. Note that the same reference numerals are given to the same parts as those described in the related art section.

Reference numeral 1 denotes an N-type semiconductor substrate, and a plurality of grooves (or holes) 3 (in this example, two) are formed by etching on the upper surface of the semiconductor substrate 1 at a location where an isolation diffusion section is to be formed.
1a and 31b are formed. Also, a plurality of (three in this example) grooves (or holes) 32 are formed on the bottom surface by etching.
a, 32b, and 32c are formed. As shown in FIG. 2, the grooves 32a, 32b, and 32c are
A, 31b are arranged alternately. That is, the grooves 32a, 32b, and 32c are formed so that the space between the grooves 32a and 32b faces the groove 31a, and the space between the grooves 32b and 32c faces the groove 31b. After this, these grooves 31a, 31b, 32a, 3
As shown in FIG. 1(b), a separation/diffusion section 4 is formed in the portion where 2b and 32c are formed.

Thereafter, as shown in FIG. 1(C), a P layer 11 is formed as an anode part on the lower surface of the N-type semiconductor substrate 1 between the separation diffusion parts 4.
A P"1i12 is formed on the upper surface as a gate part. Next, a N0 layer 13 is formed as a cathode part on a part of the P+ layer 12.
After forming P′ layer If p” layer I2 and N+ layer 1
3, an anode electrode 15 and a gate electrode 1 in contact with each other.
6 and a cathode electrode 17 are formed. Finally, as shown in FIG. 1(d), a thyristor chip is obtained by cutting approximately the central portion of the separation/diffusion section 4 by a dicing method. Note that 2 is an oxide film, and 10 is a NN that originally constituted the semiconductor substrate 1.

Although this embodiment has been explained using a method of forming a thyristor chip as an example, the present invention is not limited to this and is applicable to any method of forming a semiconductor device that requires the formation of an isolation diffusion section. be able to.

<Effects of the Invention> As explained above, the method for forming a semiconductor device of the present invention has the following effects:
A plurality of grooves or holes are formed on one surface of a portion of a semiconductor substrate where an isolation diffusion portion is to be formed, and a plurality of grooves or holes arranged alternately with the grooves or holes are formed on the other surface, and then the isolation diffusion portion is formed. Form.

Therefore, even if the diameter of the wafer increases and the thickness of the semiconductor substrate increases, according to the present invention, the depth at which impurities are diffused to form the isolation diffusion portion in the semiconductor substrate can be adjusted according to the present invention. Compared to the case where grooves (or holes) are not provided by this method, the separation and diffusion part can be formed in a short time because it is shallower, and the thickness of the separation and diffusion part is smaller than the thickness of the separation and diffusion part in which conventional grooves are formed. Since it is large, it has the advantage that cracks are less likely to occur at the location where the separation/diffusion section is formed.

[Brief explanation of the drawing]

FIG. 1 is an explanatory cross-sectional view for explaining one embodiment of the present invention, in which FIG. 1(a) shows a state in which a groove or hole is formed in a semiconductor substrate, and FIG. 1(b) shows a state in which a groove or hole is formed in a semiconductor substrate, and FIG. Figure 1 (C) shows the state in which the thyristor is formed, Figure 1 (C) shows the state in which the thyristor is formed.
d) shows the state where the image is divided into chips and parts. FIG. 2 is a drawing for explaining the conventional method of forming SIRISK, in which FIG. 2(a) is a cross-sectional explanatory diagram of a state in which separation and diffusion has been performed on a substrate, and FIG. FIG. 3 is an explanatory cross-sectional view of a state in which the cyrisk is formed and then divided into chips. 1...Semiconductor substrate, 31a, 31b, 32a
, 32b, 32c...Groove (or hole), 4
...Separation and diffusion section. Patent distributor Sharp Corporation

Claims (1)

[Claims] (1) In a method for forming a semiconductor device in which an isolation diffusion portion is formed at a predetermined location on a semiconductor substrate, a plurality of grooves or holes are formed on one surface of the location, and a plurality of grooves or holes are formed on the other surface alternately with the trenches or holes. 1. A method for forming a semiconductor device, characterized in that the separation diffusion portion is formed after forming a plurality of arranged grooves or holes.