JPH02156540A - Manufacture of semiconductor device - Google Patents

Abstract

PURPOSE:To realize an epitaxial layer of high quality from which impurities of heavy metals or the like have been gettered by a strain layer to minimize crystal defects therein, by forming the strain layer in a specific region on the surface of a semiconductor single crystal substrate before forming the epitaxial layer. CONSTITUTION:An aluminum film 12 is formed on the surface of a semiconductor single crystal substrate 11 and a part of the aluminum film corresponding to a scribing line region 14 serving as a separating region for separating the substrate into semiconductor chips is removed by photolithography. Then, laser beams 15 are applied to the surface of the semiconductor single crystal substrate 11 to produce a strain layer 16, while no strain layer is produced in the semiconductor single crystal substrate covered with the aluminum film 13 which reflects the laser beams. The aluminum film 13 is then removed completely and an epitaxial layer is grown. Crystal defects are created in the epitaxial layer formed on the strain layer 16 to provide a crystal defect region 18 while, around the region 18, there is formed an epitaxial layer 17 of high quality from which impurities have been gettered by the strain layer 16 to minimize crystal defects.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for manufacturing a semiconductor device, and particularly to gettering technology.

[Conventional technology]

Conventionally, the extrinsic gettingtering method, in which a strained layer is intentionally introduced on the back surface of a semiconductor single crystal substrate and used as an absorption source for impurities that adhere during the process, includes sandblasting method 1 method of creating mechanical scratches,
There are laser irradiation methods, ion implantation methods, and methods of attaching a nitride film or polysilicon film.

[Problem to be solved by the invention]

All of the above-mentioned conventional gettering methods do not necessarily produce sufficient effects because they form a strained layer on the back surface, and have the drawback that crystal defects occurring in the epitaxially grown layer cannot be completely suppressed.

[Differences between the invention and the prior art]

The above-mentioned conventional gettering method attempts to obtain a gettering effect by forming a strained layer on the back surface of a semiconductor single-crystal substrate, whereas the present invention aims to obtain a gettering effect by forming a strained layer on the back surface of a semiconductor single-crystal substrate. The difference is that a higher gettering effect can be obtained because of the formation.

[Means to solve the problem]

A method for manufacturing a semiconductor device according to the present invention includes a step of forming a strained layer in a specific region of a semiconductor single crystal substrate surface, and a step of forming an epitaxial growth layer after the step.

〔Example〕

The present invention will be explained with reference to the drawings.

FIG. 1 is a longitudinal sectional view of a semiconductor device showing an embodiment of the method for manufacturing a semiconductor device of the present invention.

First, as shown in FIG. 1(a), an aluminum film 12 is formed on the surface of a semiconductor single crystal substrate 11 by sputtering aluminum to a thickness of, for example, about 1 μm.

Next, as shown in FIG. 1(b), the aluminum film in the scribe line region 14, which is the separation region of each semiconductor chip, is removed by photolithography. For etching aluminum, for example, phosphoric acid: nitric acid: acetic acid: water = 16: [2:1
Use a mixture of

Next, as shown in FIG. 1(c), a semiconductor single crystal substrate 11
For example, by irradiating the surface of the strained layer 1 with a Q-switched Nd:YAG laser beam 15 having an energy density of about 20 J/cni.
form 6. At this time, since the aluminum film 13 reflects the laser beam, no strained layer is formed on the semiconductor single crystal substrate under the aluminum film 13.

Next, as shown in FIG. 1(d), the aluminum film 13 is completely removed using, for example, a mixed solution of phosphoric acid:nitric acid:acetic acid:water=16:1:2:1.

Next, as shown in FIG. 1(e), an epitaxial growth layer is formed on the semiconductor single crystal substrate 11.

At this time, the semiconductor single crystal substrate 1 is heated using hydrogen chloride gas, etc.
Cleaning step 1 is unnecessary.

Crystal defects are generated in the east epitaxial growth layer formed on the strained layer 16 to form a crystal defect region 18, but around the crystal defect region 18 there is a high quality layer in which the generation of crystal defects gettered by the strained layer 16 is suppressed. An epitaxial growth layer 17 is formed.

FIG. 2 is a longitudinal sectional view of another embodiment of the invention.

First, as shown in FIG. 2(a), an oxide film 22 is formed on the surface of a semiconductor single crystal substrate 21 by, for example, about 8,000 to 9,000 people, and the oxide film 22 in the scribe line area 23 is coated with a solution of, for example, hydrofluoric acid:hydrogen 1:20. A patterned oxide film 22 is formed by etching.

Next, as shown in FIG. 2(b), the semiconductor single crystal substrate 21 is placed into an ultrasonic generator 25 filled with pure water 24. and for example about 10 to 20 minutes, such as about 20 to 30 minutes.
KH7, generates 100-300W ultrasonic waves. At this time, a strained layer 28 is formed in the scribe line region 23.

Next, as shown in FIG. 2(c), an epitaxial growth layer is formed on the semiconductor single crystal substrate 21.

The following is the same as the embodiment shown in FIG.

Note that the method for forming the strained layer is not limited to laser irradiation and ultrasonic waves, and other methods may be used.

〔Effect of the invention〕

As explained above, the present invention forms a strained layer in a specific region on the surface of a semiconductor single crystal substrate and then forms an epitaxial growth layer, so that the strained layer getters heavy metal impurities and suppresses the occurrence of crystal defects. This has the effect of forming a high quality epitaxial growth layer.

Scribe line area, 15... Laser light, 16
...Strained layer, 17...Gettered epitaxial growth layer, 18...Crystal defect region, 21...Semiconductor single crystal substrate, 22...・
・Patterned oxide film, 23...Scribe line area, 24...Pure water, 25...
Ultrasonic generator, 26...Gettered epitaxial growth layer, 27...Crystal defect region, 28...Strained layer.

Agent Patent Attorney Susumu Uchihara

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view of an embodiment of the present invention. FIG. 2 is a longitudinal sectional view of another embodiment of the invention. 11... Semiconductor single crystal substrate, 12...
Aluminum film, 13... Patterned aluminum film, 14... (cLノ(I)) (C) U) (e) Half (Foundation) (a) Kaya 2 figure

Claims (1)

[Claims] 1. A method for manufacturing a semiconductor device, comprising the steps of forming a strained layer in a specific region on a surface of a semiconductor single crystal substrate, and forming an epitaxial growth layer after the step.