JPH07106288A - Method of forming semiconductor substrate - Google Patents

Abstract

PURPOSE:To eliminate imperfect start of cutting and irregular qualities of a slice surface, and prevent precipitation of abrasive grains in a tank, by supplying slurry for slice from above the wire of a multiwire sawing equipment when a semiconductor ingot is sliced. CONSTITUTION:In the method of forming a semiconductor substrate wherein a plurality of semiconductor substrates are formed by slicing a semiconductor ingot 1 with a multiwire sawing equipment, a supply port 5 of slurry for slice is installed above a semiconductor substrate, and slurry is supplied from above a wire 2. A slurry pad 6 is formed on the facing part of a slurry supply nozzle 5a, in order to uniformly supply the slurry to many wires 2. Thereby the slurry can be supplied always in the same condition, and imperfect start of cutting, irregular qualities of a slice surface, and precipitation of abrasive grains in a tank can be prevented.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for forming a semiconductor substrate, and more particularly to a method for forming a semiconductor substrate for solar cells by slicing a semiconductor block with a multi-wire saw device.

[0002]

2. Description of the Related Art Conventionally, when a semiconductor substrate for a solar cell is formed of polycrystalline silicon or the like, an ingot of polycrystalline silicon is formed by, for example, a casting method, and the ingot is cut into a predetermined size to form a semiconductor block. The semiconductor block was sliced into multiple pieces with a multi-wire saw device.

As shown in FIG. 3, a multi-wire saw device used for slicing a semiconductor block has three rollers 13a, 13b and 13c arranged around a slurry reservoir 11 provided with a slurry supply port 12. However, the wire 14 is stretched over the rollers 13a, 13b, 13c.

When slicing the semiconductor blocks 15a and 15b, a slurry containing abrasive grains is supplied from the slurry supply port 12 and three rollers 13a, 13b and 13 are used.
The semiconductor lumps 15a and 15b are sliced by gradually lowering the plurality of semiconductor lumps 15a and 15b to the wire 14 portion while rotating the wire 14 at high speed between c. In this case, the semiconductor blocks 15a and 15b are
It is attached to the base material 16a, 16b made of carbon or the like,
Even if the semiconductor blocks 15a and 15b are sliced, the individual semiconductor substrates are sliced so as not to fall apart. Further, the slurry is sequentially supplied from the supply port 12 and slices the semiconductor chunks 15a and 15b while overflowing.

[0005]

However, in this conventional method for forming a semiconductor substrate, since the wire 14 is run at a high speed, the slurry in the slurry reservoir 11 scatters and the semiconductor lumps 15a and 15b start to be cut. There is a problem that the semiconductor blocks 15a and 15b are not vertical, and a load is increased during the slicing of the semiconductor blocks 15a and 15b, and wire marks are generated on the sliced surface to deteriorate the quality of the semiconductor substrate. That is, when the wire is at a high speed, a large amount of the slurry overflows in the wire scanning direction, and the liquid surface of the slurry at the wire inlet and outlet is not horizontal. In this case, when slicing the ingot on the inlet side of the wire, the slurry is below the wire, and when slicing the ingot on the outlet side of the wire, the slurry is above the wire. Although the slices are sliced at the same time on the left and right, the conditions are different and the sharpness of the wire is completely different. If the cutting start is not vertical, cracks will occur when devices such as solar cells are created in the subsequent process, and devices cannot be created.

Further, the high speed running of the wire 14
The slurry in the slurry collecting tank 11 convects, and the slurry containing a lot of chips stagnates in the slurry collecting tank 11, and as a result, the semiconductor blocks 15a and 15b must be sliced with the slurry containing a large amount of chips. However, there is also a problem that wire marks are generated on the sliced surface to deteriorate the quality of the semiconductor substrate.

Further, there is also a problem that the abrasive grains in the slurry settle on the bottom of the slurry pool tank 11, and the slurry pool tank 11 must be cleaned after each slice is completed.

[0008]

The method of forming a semiconductor substrate according to the present invention has been made in view of the above problems of the prior art, and is characterized in that a semiconductor block is formed by a multi-wire saw. In the method for forming a semiconductor substrate in which a plurality of semiconductor substrates are formed by slicing with a device, the slice slurry is supplied from above the wire of the multi-wire saw device when slicing the semiconductor mass.

[0009]

With the above construction, the slurry can be always supplied in the same state, and defects such as the beginning of cutting and variations in the quality of the sliced surface are eliminated. Further, the abrasive grains do not settle in the tank, cleaning after slicing is not required, and the setup change time for setting the next semiconductor block after slicing can be shortened.

[0010]

Embodiments of the present invention will now be described in detail with reference to the accompanying drawings. FIG. 1 is a diagram for explaining a method for forming a semiconductor substrate according to the present invention, in which 1 is a semiconductor block, 2 is a wire, and 3 is a roller for running the wire 2 at a high speed.

The semiconductor block 1 is composed of, for example, a polycrystalline silicon ingot formed by a casting method or the like and cut into a predetermined size. A base material 4 made of carbon or the like is attached to one surface of the semiconductor block 1 with an epoxy adhesive or the like.

The wires 2 are, for example, piano wires having a diameter of about 160 μm, and are arranged at a pitch of about 500 μm. This wire 2 is, for example, 50
It runs at a high speed of about 0 m / min.

A slicing slurry supply port 5 is provided above the semiconductor block 1 so that the slurry is supplied from above the wire 2. That is,
In the example shown in FIG. 1, two semiconductor lumps 1 are installed, and even if the wire 2 is rotated in any direction, three slurry supply nozzles 5a are provided so that the slurry can be uniformly supplied to the two semiconductor lumps 1. It is provided. Slurry supply nozzle 5a
A slurry receiver 6 is provided in the confronting portion so that the slurry can be uniformly supplied to a large number of wires 2. This slicing slurry is composed of, for example, mineral oil mixed with abrasive grains.

Below the wire 2, a semiconductor block 1 is formed.
A tank 7 is provided for receiving the scraps that may fall when slicing the. No slurry is stored in this tank 7.

FIG. 2 is a perspective view of the slurry supplying portion. For the slurry, a slurry receiver 6 is provided below a slurry supply nozzle 5a having a hole in a pipe, and the slurry is uniformly supplied from above the wire 2 in a curtain shape. That is, for example, 40 liter / min or more is supplied from the slurry supply nozzle 5a to each slurry supply nozzle.

[0016]

As described above, according to the method for forming a semiconductor substrate of the present invention, when slicing a semiconductor block, the slurry for slicing is supplied from above the wire of the multi-wire saw device, so that the slurry is It can always be supplied in the same state, eliminating defects in the beginning of cutting and variations in the quality of sliced surfaces. Further, the abrasive grains do not settle in the tank, cleaning after slicing is not required, and the setup change time for setting the next semiconductor block after slicing can be shortened.

[Brief description of drawings]

FIG. 1 is a diagram illustrating a method for forming a semiconductor substrate according to the present invention.

FIG. 2 is a diagram for explaining an essential part of a method for forming a semiconductor substrate according to the present invention.

FIG. 3 is a diagram for explaining a conventional method for forming a semiconductor substrate.

Claims (1)

[Claims] 1. A method of forming a semiconductor substrate, comprising slicing a semiconductor block with a multi-wire saw device to form a plurality of semiconductor substrates, wherein when slicing the semiconductor block, a slice for slicing is applied from above a wire of the multi-wire saw device. A method for forming a semiconductor substrate, which comprises supplying a slurry.