Method for producing semiconductor wafer

Abstract

A semiconductor wafer is produced by a method comprising a slicing step of cutting out a thin disc-shaped semiconductor wafer from a crystalline ingot; and a fixed grain bonded abrasive grinding step of sandwiching the semiconductor wafer between a pair of upper and lower plates each having a pad of fixed grain bonded abrasive to simultaneously grind both surfaces of the semiconductor wafer.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention[0001]This invention relates to a method for producing a semiconductor wafer, and more particularly to a method for producing a semiconductor wafer by cutting out a thin disc-shaped semiconductor wafer from a crystalline ingot and then subjecting both surfaces thereof to a mirror finishing. 2. Description of the Related Art[0002]The conventional method for producing a semiconductor wafer typically comprises a series of a slicing step→a first beveling step→a lapping step→a second beveling step→a one-side grinding step→a double-sided polishing step→a one-side finish polishing step in this order.[0003]In the slicing step, a thin disc-shaped semiconductor wafer is cut out from a crystalline ingot. In the first beveling step, an outer peripheral portion of the cut semiconductor wafer is beveled to suppress the occurrence of cracking or chipping in the semiconductor wafer at the subsequent lapping step. In the lapping step, the beveled ...

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Benefits of technology

[0010]It is, therefore, an object of the invention is to advantageously solve the above-mentioned problems and to provide a method for producing a semiconductor wafer wherein both surfaces of a semiconductor wafer cut out from a crystalline ingot can be mirror-finished by a simple process flow obtained by omitting at least the beveling step, and also the semiconductor wafer can be obtained cheaply by reducing the machining allowance of silicon material in the semiconductor wafer to reduce the kerf loss of the semiconductor material. Particularly, the invention develops a remarkable effect when the semiconductor wafer is a silicon wafer having a large diameter of not less than 450 mm.

[0011]In order to solve the above problems, the inventors have made various studies about a method for producing a semiconductor wherein the number of production steps when a semiconductor wafer cut out from a crystalline ingot is rendered into a double-sided mirror-finished semiconductor wafer is decreased but also silicon kerf loss in the semiconductor wafer is reduced as compared with those of the conventional method.

[0012]As a result, it has been found that the number of production steps can be decreased but also the machining allowance of the semiconductor wafer can be reduced as compared with the conventional method by conducting a fixed grain bonded abrasive grinding step of simultaneously conducting a high-speed treatment from rough grinding to finish grinding on both surfaces at once, instead of the lapping step and the one-side grinding step in the above conventional method, and a chemical treating step of simultaneously conducting not only reduction of working strain on surfaces and an end face of the semiconductor wafer but also a beveling.

[0017]According to the production method of the semiconductor wafer according to the invention, a fixed grain bonded abrasive grinding step and a chemical treating step are conducted between the slicing step and the double-sided polishing step, whereby the number of production steps for the semiconductor wafer is shortened as compared with the conventional method and the machining allowance of the semiconductor wafer can be reduced to reduce the kerf loss of the semiconductor material to thereby obtain the semiconductor wafer cheaply.

[0018]Also, the flatness of the semiconductor wafer can be improved by reducing the machining allowance of the semiconductor wafer. Furthermore, a semiconductor wafer having an epitaxial layer can be obtained by conducting an epitaxial layer growing step between the chemical treating step and the double-sided polishing step or after the double-sided polishing step. The production method of the semiconductor wafer according to the invention is especially suitable for the production of silicon wafers having a large diameter of not less than 450 mm.

Problems solved by technology

In the aforementioned conventional method, a double-sided mirror finished semiconductor wafer is produced through the two beveling steps, the lapping step and the one-side grinding step, so that there are problems that a kerf loss of a semiconductor material (loss of semiconductor material due to the increase of lapped scrap and one-side ground scrap) is brought about due to a large number of steps.

In the production method of the semiconductor wafer disclosed in this patent document, the problem of growing the size of the lapping apparatus in the production of the large-diameter semiconductor wafer is solved and the first beveling step before the double-sided grinding step can be omitted, but the double-sided grinding step and the one-side grinding step are conducted, and hence the machining allowance of the silicon material is still large, which remains as a problem about the kerf loss.

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