KR101112743B1 - Wire Saw For Cutting Ingot - Google Patents

Abstract

The present invention relates to a wire saw for enabling thinner cutting of single crystal ingots. The present invention relates to a conventional wire saw for cutting an ingot by a first wire installed on a pair of first main rollers, the pair of second main rollers and a second drive roller for driving the second main rollers; ; A second annular groove having the same pitch as the first annular groove of the first main roller and a second wire wound on the outer circumferential surfaces of the second main roller and the second driving roller, and between the second main rollers A surface formed by the disposed second wires is formed below a surface formed by the first wires disposed between the first main rollers; And a second wire to cut the remaining portion after the ingot is cut by the first wire.

Ingot, cutting, wafer, wire saw

Description

Wire Saw For Cutting Ingot

The present invention relates to a wire saw for cutting ingots, and more particularly, to a wire saw for cutting a single crystal ingot to produce a thinner wafer.

In order to manufacture a wafer, a silicon wafer is fabricated by thinly cutting a single crystal ingot, and then the steps of chamfering, lapping, acid etching, and polishing are sequentially performed on the silicon wafer.

In order to cut a conventional single crystal ingot, a wire saw 1 as shown in FIG. 1 is used. The wire saw has two main rollers 11 and 12 and a driving roller 13 arranged at prescribed intervals, and is fixed on the outer circumferential surfaces of the main rollers 11 and 12 and the driving roller 13 as shown in FIG. Pitch annular grooves 20 are formed, and the wires 30 are wound around a pair of reels 40, respectively. The wire 30 wound along the annular groove 20 is disposed between the main rollers 11 and 12. When the ingot 50 is lowered on the upper side of the arranged wire and the slurry is supplied to the wire reciprocating, the ingot is gradually cut by the abrasive particles mixed in the slurry.

The wire is usually made of spring steel having a diameter of about 140 ~ 160 ㎛, etc., the slurry is produced in the form of a mixture of silicon carbide oil or water having a particle size of about # 1000 ~ 1500.

 In the case of using a wire having a diameter of about 160 μm in consideration of the diameter of the wire and the abrasive grain size, the pitch of the annular groove processed in the roller is processed to about 445 to 479 μm, and the wafer has a thickness of about 190 μm. Will be cut.

It is known that it is almost impossible to process the thickness of a wafer to 170 micrometers or less by using the conventional wire saw as mentioned above by the processing precision of an annular groove, a problem of wire installation, etc.

An object of the present invention is to provide a wire saw for producing a wafer having a thickness of 150 µm or less from a single crystal ingot.

A pair of first reel for supplying a first wire, a pair of first main rollers provided on a first wire path between the first reels and having a first annular groove of a constant pitch on its outer peripheral surface; In the ingot cutting wire saw made of a first drive roller, the ingot is cut by the first wire disposed between the first main roller receives the ingot from the upper side,

A second drive roller for driving a pair of second main rollers and the second main roller;

A second annular groove provided on the outer circumferential surfaces of the second main roller and the second driving roller with the same pitch as the first annular groove of the first main roller, and the second wire being wound;

A pair of second reels for supplying said second wire;

A second tension adjusting part positioned between the second main roller or the second driving roller and the second reel to adjust the tension of the second wire;

A second driving motor for driving the second driving roller;

A control unit for controlling rotation of the second reel and the second driving motor;

A slurry tank for storing the slurry;

It comprises a slurry supply for supplying or recovering the slurry on the surface of the first and second wires;

A surface formed by the second wires disposed between the second main rollers is formed below a surface formed by the first wires disposed between the first main rollers;

And a second wire to cut the remaining portion after the ingot is cut by the first wire.

The wire soo,

A temperature measuring unit measuring a temperature of the slurry;

A temperature controller for controlling the temperature of the slurry;

It characterized in that to drive the cooling device by the control unit to maintain the temperature of the slurry within a certain range.

The base solution of the slurry used in the present invention is characterized in that it is prepared by mixing potassium hydroxide or sodium hydroxide with water or glycol.

The slurry used in the present invention is more preferably prepared by mixing silicon carbide powder or alumina oxide powder having a particle size of # 2000 or more in the base solution of the slurry.

According to the present invention, it is possible to cut a single crystal ingot into a wafer having a thickness of 150 μm or less, and also has an effect of minimizing the wave shape of the cut surface of the wafer.

Hereinafter, the present invention will be described in more detail with reference to the accompanying drawings.

3 shows an embodiment of the present invention.

A pair of first reels (not shown) for supplying a first wire, and a pair of first reels provided on a first wire path between the first reels and having annular grooves of a constant pitch on an outer circumferential surface thereof; Including the first main roller 110 and the first driving roller 120, the ingot 50 by the first wire 130 disposed between the first main roller 110 receives the ingot from the upper side Since the structure to be cut is the same as that of Fig. 1 showing a conventional wire saw, a detailed description thereof will be omitted.

In this embodiment, as shown in FIG. 4, it is possible to again cut the ingot remaining 51 after being cut by the first wire 130 by the second wire 230. To this end, a pair of second main rollers 210 and a second driving roller 220 for driving the second main rollers 210 are provided.

Although not shown, a second annular groove provided on the outer circumferential surfaces of the second main roller 210 and the second driving roller having the same pitch as the annular groove of the first main roller and the second wire being wound; A pair of second reels for supplying said second wire; A second tension adjusting part positioned between the second main roller or the second driving roller and the second reel to adjust the tension of the second wire; A second driving motor for driving the second driving roller; Having a control unit for controlling the rotation of the second reel and the second drive motor will be fully understood by those skilled in the art that the configuration is necessary through the disclosure of the present invention without having to be described through drawings.

The surface formed by the second wires 230 disposed between the second main rollers 210 is formed below the surface formed by the first wires 130 disposed between the first main rollers 110. The intervals of the first and second wires 130 and 230 are equally arranged by the pitches P1 and P2 of the first and second annular grooves that are the same, and are also cut by the first wire 130 as shown in FIG. 4. The remaining remainder 51 is arranged to allow the second wire 230 to cut.

Accordingly, the first and second annular grooves for winding the first and second wires can process wafers of much smaller thickness than the wafers formed only by the first wire, even when using a larger pitch than the conventional one, and are easy to manufacture and install. There is an effect that becomes.

In addition, when the wire saw is operated, the slurry 400 is supplied to the ingot cutting positions of the first and second wires. For this purpose, the slurry tank 300 and the slurry supply unit 310 are provided.

The slurry used in this example is a solution obtained by mixing potassium hydroxide or sodium hydroxide with water or glycol as its base solution, and a slurry was prepared by mixing silicon carbide powder having a particle size of # 2000 or more with this base solution.

Since the slurry contains potassium hydroxide or sodium hydroxide, the ingot can be chemically polished, and this chemical polishing works in conjunction with mechanical polishing of silicon carbide or alumina to make the cutting operation easier.

In the present embodiment, a mixture of potassium hydroxide and glycol in a ratio of 48:52 and silicon carbide powder of particle size # 2000 were mixed at a weight ratio of 50:50 to produce a single crystal wafer for solar cells. The temperature of the slurry in the slurry tank was maintained in the range of about 30 to 70 degrees Celsius by the temperature measuring unit (not shown) and the temperature controller 320 for adjusting the temperature of the slurry.

Naturally, the temperature controller 320 may use a cooling device or a heating device such as a fan or a heater.

The diameter of the 1st and 1st wire was 160 micrometers, and the target thickness of the wafer was set to 130 micrometers, and the ingot of 25 cm in length, 10 cm in width and height was cut | disconnected. The cutting time was about 8 hours and 30 minutes, resulting in a total of 757 wafers. Of these, 640 wafers were obtained in the actual thickness range of 125 to 140 μm, and the remaining wafers were broken. As a countermeasure according to the damage, it is determined that it is possible to adjust the setting environment such as the feed speed of the wire and the falling speed of the ingot within the scope of the present invention.

In addition, the surface of the cut wafer was processed more uniformly and better than using a conventional slurry by the slurry of this example in which chemical polishing was added to mechanical polishing.

1 is a view showing the form of a conventional wire saw.

Figure 2 is a cross-sectional view showing the arrangement of the annular groove and the wire of the main roller.

3 shows a wire saw of the present invention.

Figure 4 is a view showing the ingot and the wire during the cutting process according to the present invention.

Claims (4)

A pair of first reel for supplying a first wire, a pair of first main rollers provided on a first wire path between the first reels and having a first annular groove of a constant pitch on its outer peripheral surface; In the ingot cutting wire saw made of a first drive roller, the ingot is cut by the first wire disposed between the first main roller receives the ingot from the upper side, A second drive roller for driving a pair of second main rollers and the second main roller; A second annular groove provided on the outer circumferential surfaces of the second main roller and the second driving roller with the same pitch as the first annular groove of the first main roller, and the second wire being wound; A pair of second reels for supplying said second wire; A second tension adjusting part positioned between the second main roller or the second driving roller and the second reel to adjust the tension of the second wire; A second driving motor for driving the second driving roller; A control unit for controlling rotation of the second reel and the second driving motor; A slurry tank for storing the slurry; It comprises a slurry supply for supplying or recovering the slurry on the surface of the first and second wires; A surface formed by the second wires disposed between the second main rollers is formed below a surface formed by the first wires disposed between the first main rollers; An ingot cutting wire saw, wherein the second wire is cut by the remaining portion after the ingot is cut by the first wire. The method of claim 1, A temperature measuring unit measuring a temperature of the slurry; And a temperature controller for controlling the temperature of the slurry; Ingot cutting wire saw to drive the cooling apparatus by the control unit to maintain the temperature of the slurry within a certain range. delete delete

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