JPS60206590A - Production of semiconductor wafer - Google Patents

Abstract

PURPOSE:To obtain efficiently semiconductor wafers having a uniform thickness by irradiating alternately laser beams from both ends of the ingot of a semiconductor single crystal and cutting the ingot. CONSTITUTION:The laser beams 2 are alternately irradiated on the ingot 21 of the semiconductor single crystal from both sides thereof. The figure shows the case in which three units of irradiating devices 23 for the laser beams 22 are used. Said devices may be one or two units or >=3 units by moving adequately the devices. The system of disposing two units, each one on each side and cutting the ingot by irradiating alternately the beams is more economical in actuality. The ingot 21 is thus made of the wafers 31 and the allowances 32 for cutting and the waste arising from the ununiform thickness of the wafers 31 is obviated. Cutting out of the wafers 31 in the greater quantity than in the conventional practice from the same ingot is eventually made possible.

Description

[Detailed description of the invention] The present invention relates to a method for manufacturing semiconductor wafers.

Semiconductor single crystal ingots are manufactured by conventionally known methods such as the horizontal Bridgman method (H-1 method), the temperature gradient method <GF method), and the Czochralski method (C.7 method).

This semiconductor single crystal was cut into an ingot using a laser beam.

Conventionally, this laser beam was irradiated only from one side of the semiconductor single crystal ingot, which resulted in uneven thickness of the wafer from one end to the other, as shown in Figure 1. There was a lot of waste.

In FIG. 1, 11 is a wafer and 12 is a cutting margin.

In view of this situation, it is an object of the present invention to provide a method for manufacturing semiconductor wafers with uniform wafer thickness and no waste.

The gist of the present invention is to provide a method for manufacturing a plurality of semiconductor wafers by cutting a semiconductor single crystal ingot with a laser beam, characterized in that the ingot is cut by alternately irradiating the laser beam from both sides of the ingot. This is the manufacturing method.

An embodiment of the present invention is shown in FIG. 2. In FIG. 2, 21 is a semiconductor single crystal ingot, and laser beams 22 are alternately irradiated from both sides of the ingot.

Although FIG. 2 shows that there are three laser beam irradiation devices 23, there may be one, two, or four or more laser beam irradiation devices 23 by moving them as appropriate.

In reality, it seems economical to arrange two machines, one on each side, and perform irradiation and cutting alternately.

The ingot thus obtained becomes a wafer 31 and a cutting margin 32 as shown in FIG. 3, and since the thickness of the wafer 31 is uniform, there is no waste.

As explained above, with the wafer manufacturing method of the present invention, the wafer thickness is uniform and there is no waste. Additionally, a larger number of wafers can be cut from the same ingot than in conventional methods.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram showing a wafer and cutting allowance according to a conventional manufacturing method, and FIG. 2 is an explanatory diagram showing an embodiment of the present invention.
FIG. 3 is an explanatory diagram showing a wafer and a cutting margin according to an embodiment of the present invention. 21: ingot, 22: laser beam, 23: irradiation device, 31: wafer, 32: cutting allowance. 1st item 2nd illustration 3I2]

Claims (1)

[Claims] A method for manufacturing a plurality of semiconductor wafers by cutting an ingot of a semiconductor single crystal with a laser beam, the method comprising cutting the ingot by alternately irradiating the ingot with a laser beam from both sides.