JPH05309644A - Cutting device of semiconductor bar - Google Patents

Abstract

PURPOSE:To provide a cutting device for a wafer in a manufacturing process of a semiconductor material, which cut off especially both faces in parallel with each other at favorable flatness. CONSTITUTION:At the time of cutting-off of a semiconductor by making use of a wire 1, a processing liquid flows over the whole of the wire 1 by setting up the wire 1 to tilt in a vertical direction, and a wafer which is uniform and has favorable accuracy is obtained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wafer cutting device in a semiconductor material manufacturing process. In particular, it relates to a device for cutting both surfaces in parallel and with good flatness.

[0002]

2. Description of the Related Art FIG. 2 shows an example of a conventional wafer cutting device. In this apparatus, a metal wire -1 is pulled through a pulley 2, and the wire 1 is pressed against a semiconductor rod 4 while being fed with a working fluid in the direction of arrow B, and the semiconductor rod is raised in the direction of arrow A. It is cut by this. That is, a rod-shaped crystal is cut into a wafer.

However, since the working liquid applied to the wire with respect to the semiconductor rod is non-uniformly distributed in the area where the wire acts, the thickness of the two faces of the cut wafer becomes non-uniform or flat. Instable and stable processing becomes difficult. This is especially noticeable on the inlet side and the outlet side in the wire running direction. Conventionally, the working fluid is installed on the inlet side, and the working fluid has a structure that tends to stay near the inlet side.

As a result, the amount of processing on the inlet side is large, and the amount of processing on the outlet side is considerably small, and the cutting margin is large at the inlet and small at the outlet, resulting in uneven thickness of the cut wafer. .. Recently, the demands on the flatness of the wafer are particularly strict, and the necessity of establishing a processing technique for cutting the wafer with a good flatness by cutting as a primary process is increasing.

[0005]

When cutting with a wire, the working liquid is unevenly distributed in the section where the wire acts on the semiconductor rod, resulting in uneven wafer thickness and flatness. Is to provide a wafer with higher accuracy.

[0006]

SUMMARY OF THE INVENTION The present invention has solved the above-described problems in a wire saw for cutting a semiconductor rod into a flat plate shape by setting the wire at an angle with respect to the vertical direction.

[0007]

The present invention will be described with reference to FIG. The wire 1 is stretched via a pulley 2 and driven along the pulley 2, and the wire is set to be inclined at an angle of θ ± α with respect to the vertical direction. Here, the tilt angle θ is a standard specification value of the cutting device, and varies depending on the type and size of the semiconductor to be cut. The adjustment angle α is a value adjusted with respect to the difference in the processing conditions such as the viscosity of the processing liquid, the rate of abrasive grains in the liquid, and the wire speed, and the change over time in the processing state. The working liquid is poured into the wire from the position of the upper nozzle 3 with respect to the wire. The semiconductor rod 4, which is a material, has a columnar shape, and its axis is arranged in a direction perpendicular to the paper surface.

The semiconductor rod is fixed to the moving table 5 by a semiconductor rod fixing device (not shown). The movable table 5 is slidably arranged on the guide table 6 along the inclination direction. Therefore, the semiconductor rod 4 can move toward and away from the wire 1. The moving axis of the moving table 5 has an inclination of θ ± α with respect to the vertical direction, and faces the wire 1 running in the direction of arrow B.
Therefore, by moving the moving table 5 along the guide table 6 in the direction of arrow A, the semiconductor rod is pressed against the wire and the wafer is cut out.

During cutting, the working liquid supplied from the nozzle 3 smoothly moves by gravity along the wire set to the inclination angle θ ± α. As a result, since the semiconductor rods 4 are uniformly distributed in the section where the wire acts and flow smoothly, the processing chips can be discharged smoothly. θ varies depending on the processing conditions such as the viscosity of the processing liquid, the rate of abrasive grains in the liquid, and the wire speed, but is preferably 20 ° to 70 °, and α
Depends on the size and type of semiconductor rod to be cut.
° to 20 ° is preferred.

In the case of one wire 1, the semiconductor rod 4 is sliced and then either the guide table 6 or the wire 1, the pulley 2, and the cutting device 7 equipped with the nozzle 3 is moved in the direction perpendicular to the plane of the drawing. You can continue cutting the rod.
Alternatively, if a plurality of wires are set in parallel, a plurality of wafers can be cut out at once by one operation of the moving table.

According to the present invention, since the working fluid flows evenly over the entire wire by arranging the wire 1 so as to be inclined, the working fluid can be worked uniformly.
The slicing operation is stable, and the thickness of the cut wafer is uniform. Therefore, the slicing accuracy is improved, the slicing work is stabilized, the efficiency is improved, and the defective rate can be reduced.

[0012]

【Example】

(Example) A 6 "silicon single crystal ingot was cut by a cutting device as shown in Fig. 1. The tilt angle θ of the device was 45 °.
And the adjustment angle α was 15 °. As a comparative example, FIG.
Cutting was also performed by a conventional cutting device having no inclination shown in. Both devices run one wire in one direction, press the single crystal rod against the wire while applying the working liquid to perform one cutting, and process the next cutting part.These cycles are sequentially performed. 30 by doing
A silicon wafer was obtained.

In the method of the present invention, the average flatness is about 1.
A very good value was obtained for 5 μm, which is about 6 μm for the conventional method. Further, the cutting resistance received by the semiconductor rod during processing was stable in the case of the present invention, but in the conventional method, the processing liquid is unstable and non-uniformly distributed, so that the fluctuation becomes large and the processing speed needs to be reduced. Therefore, the processing time was 1.3 times that of the present invention. In the present embodiment, the defect rate, that is, the proportion of large cut marks and flatness exceeding 10 μm was 0% in the present invention, but 10% in the conventional method.
Became.

[0014]

As described above, by arranging the wires so as to be inclined, the working liquid flows uniformly over the wires, a uniform and highly accurate wafer is obtained, and the efficiency and yield of the slicing operation are improved.

[Brief description of drawings]

FIG. 1 is a semiconductor rod cutting apparatus according to the present invention.

FIG. 2 Conventional semiconductor rod cutting device

[Explanation of symbols]

 1 Wire 2 Pulley 3 Nozzle 4 Semiconductor Rod 5 Moving Table 6 Guide Table 7 Cutting Device

Claims (1)

[Claims] 1. A cutting device for cutting a semiconductor rod into a flat plate shape using a wire, wherein the wire is set to be inclined with respect to a vertical direction.