JP2001259990A - Wire for wire saw - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a wire for a wire saw capable of retaining a good wire form even after cutting. SOLUTION: The wire for the wire saw is used for cutting or slicing a hard material such as silicon and a solar buttery. A longitudinal residual stress of a wire surface is defined such that a difference of the maximum value and the minimum value in the case where it is measured at four points where a circumferential direction of the wire is different by every 90 deg. is made to 20 kgf/mm2 or less.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wire for a wire saw used for cutting and slicing hard materials such as silicon and solar cells.

[0002]

2. Description of the Related Art In a wire saw, a wire row in which a wire is wound around a plurality of groove rollers at a predetermined pitch is run, and while a material to be cut (work) is pressed against the wire row, the wire row and the work are joined together. This is an apparatus that cuts a work into a large number of wafers by a grinding action of abrasive grains while pouring an abrasive liquid during the process.

Meanwhile, as a characteristic required for a wire used in such a wire saw, it is important that a wire habit such as a free coil diameter, twist, and undulation does not change in the cutting process.

[0004] After cutting, if the free coil diameter becomes smaller than the initial one, or if the wire has a bad line habit such as a minute wave (undulation), there arises a problem that the accuracy of the slice surface is significantly reduced.

[0005] Therefore, the present invention is to provide a
An object of the present invention is to provide a wire for a wire saw that maintains a good wire habit.

[0006]

SUMMARY OF THE INVENTION The present invention is directed to silicon,
In wires for wire saws used for cutting and slicing hard materials such as solar cells, the residual stress in the longitudinal direction of the wire surface is the maximum value measured at four different points at 90 degrees in the circumferential direction of the wire. The difference between the minimum values is 20kgf / m
and it is characterized in that it is defined in m ² or less.

[0007] If the value of the residual stress varies in the circumferential direction, the wire habit of the wire after cutting greatly changes, causing undulation. However, as in the present invention, the residual strength in the longitudinal direction of the wire surface is reduced. When the stress is measured at four different points in the circumferential direction of the wire at 90 degrees each, the difference between the maximum value and the minimum value is 20.
When the weight is specified in the range of kgf / mm ² or less, the wire habit can be favorably maintained even after cutting.

The distribution of the residual stress on the wire surface varies depending on various conditions (die shape, reduction rate of one pass, etc.) during wire drawing. Therefore, the distribution of the residual stress on the wire surface is set to be less than 2 by the appropriate wire drawing conditions.
It is possible to make it equal to or less than 0 kgf / mm ² .

[0009] Further, as a wire for a wire saw, a preferable tensile strength is 3200 MPa or more.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION Six types of wires having different residual stresses were produced from wire for a wire saw having a diameter of 0.16 mm under different drawing conditions. Using these six types of wires, a silicon ingot was cut, and the wire habit after use was evaluated. Table 1 shows the distribution of residual stress (maximum value-minimum value of residual stress at four circumferential points: residual stress in the axial direction) and the wire habit after use.

[0011]

[Table 1]

As shown in Table 1, the difference between the maximum and the minimum of the residual stress is 20.
The wires of samples A, B and C having a weight of not less than kgf / mm ²
Bad wire habit after use. On the other hand, the maximum and minimum difference of the residual stress is 2
D, E, and F wires of 0 kgf / mm ² or less maintain a free coil diameter of 300 mm or more even after use, and have no undulation. From the above, it was confirmed that the wire of the present invention having a maximum and minimum difference in residual stress of 20 kgf / mm ² or less had a good wire habit after use.

[0013]

The wire for a wire saw according to the present invention comprises:
Since a good line habit is maintained even after use, the accuracy of the slice plane does not decrease.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Kenichi Shimizu 1-1-1 Kunyokita, Itami City Inside Itami Works, Sumitomo Electric Industries, Ltd. (72) Inventor Akito Hoshima 1-1-1 Kunyokita, Itami City No. 1 Sumitomo Electric Industries, Ltd. Itami Works (72) Inventor Yoshihiro Akabane 1-1-1, Koyo Kita, Itami-shi Sumitomo Electric Industries, Ltd. Itami Works (72) Inventor Koujiro Tono, Itami City Kitaichi Kitaichi Sumitomo Electric Industries, Ltd. Itami Works (72) Inventor Makoto Mizuhara 1-1-1, Kunyokita, Itami City Itami Works Sumitomo Electric Industries, Ltd. Itami Works F-term (reference) 3C058 AA05 AA09 CA05 CB01 DA03 DA17 3C069 AA01 BA06 BB03 CA03 EA02

Claims (2)

[Claims] 1. In a wire saw wire used for cutting and slicing hard materials such as silicon and solar cells, the residual stress in the longitudinal direction of the wire surface differs at four points by 90 degrees in the circumferential direction of the wire. A wire for a wire saw, wherein a difference between a maximum value and a minimum value when measured is defined in a range of 20 kgf / mm ² or less. 2. The wire for a wire saw according to claim 1, which has a tensile strength of 3200 MPa or more.