JPS63102868A - Cutting wire - Google Patents

Abstract

PURPOSE:To make rapid feed performable and slice time reducible as well, by forming a diamond coating film on a wire base material, in case of a cutting wire for a wire saw. CONSTITUTION:A cutting wire is made up of forming a diamond coating film on a wire base material 12 consisting of alloys of Ni-Cr, Fe-Ni and Fe-Cr-Al systems and W, Mo metals, etc., in thickness of a range of about 0.01-50mum by means of an ion-beam process, a chemical conveyance process, a microwave plasma process and so on. For example, in the microplasma process, a Ni-Cr wire 12 is passed through the inside of a reactor 7, internal pressure is adjusted to 40 Torr by an exhauster 9, by way of example, and oxygen gas is fed of a bomb 11 and methane gas out of another bomb 10, respectively, while a microwave generator 8 is operated at about 900MHz and 1KW, making it generate plasma, and the diamond coating film is separated therefrom. Thus, a silicone ingot is sliceable well in productivity and yield.

Description

[Detailed Description of the Invention] The present invention relates to a cutting wire that is particularly effectively used in a cutting method using a wire saw. The present invention relates to a cutting wire that can be significantly shortened and is suitable for use in the electronic industry, particularly for slicing crystal ingots.

Traditionally, silicon ingots have been sliced to create wafers, and various compound semiconductors, oxide single crystal/polycrystalline ceramics, glass, metals, etc. have been cut into predetermined shapes. 2. Description of the Related Art Products are manufactured and these wafers and cut products are used in various industries such as the electronic industry.

As a method for cutting or slicing these various materials, an abrasive processing method using fine abrasive grains of hard mineral material as a tool is known as a method suitable for precision finishing. This abrasive processing method is roughly divided into two methods: a method using fixed abrasive grains and a method using free abrasive grains. The method using a wire saw and the blade saw are the latter cutting methods that belong to the method using free abrasive grains.

FIGS. 1 to 3 show schematic diagrams of cutting wafers from an ingot using the above-mentioned inner peripheral blade method and a wire saw or a blade saw. That is, FIG. 1 shows a slicing method using a multi-wire saw, in which 1 is an ingot, 2 is an ingot holder, 3 is a wire guide roller, and 4 is a wire with abrasive particles attached. Apply appropriate tension and reciprocating motion to the wire 4,
The ingot 1 is sliced while applying appropriate pressure to the ingot 1. In addition, Fig. 2 shows a slicing method using a multi-blade saw, in which the ingot 1 is sliced by a blade 5 while supplying slurry in which abrasive grains are dispersed to the ingot 1. In the conventional method, a large number of wafers can be manufactured at the same time. In addition, 2' in the figure is an ingot support (adhesive wax). Furthermore, FIG. 3 shows a slicing method using an inner peripheral blade method, in which a blade 6 made of diamond abrasive grains electrodeposited on the inner peripheral portion of a donut-shaped circular base metal portion cuts the ingot 1 while rotating in the direction of the arrow. It is something to do.

As shown in Table 4 below, these three methods have a slice loss utilization rate of 72.
The highest rate was 7%, followed by the blade saw type at 64.5% and the internal blade type at 51.3%. In addition, the average parallelism is 8.5p for the internal blade method and 1 for the wire saw method.
1.0/J1. One platen type is 28.511n, but when comparing the maximum value, wire saw type one type is 35IJa
, one blade saw type 55p, inner peripheral blade type 55%,
One type of wire saw is better.

On the other hand, the thickness accuracy (400±α doors) as dimensional accuracy is α=9p for the inner peripheral blade method and α=12p for the wire saw method.
Im, the blade saw type is in the order of α=15p, and the inner peripheral blade type is superior. Furthermore, in terms of production capacity, the blade saw type has the best number of sheets per hour at 33 pieces, followed by the inner peripheral blade type with 22 pieces and the wire saw type with 20 pieces.

Also, when comparing consumable materials from a cost perspective.

In the wire saw type, the rollers around which the wire is wound are made of synthetic resin, so they wear out during use, so their lifespan has a large impact on costs, whereas in the platen type, the blade wears out after one use. However, it has to be replaced each time, which increases the cost. Considering the above points, when wafers are manufactured using the internal blade method, the wire saw method, and the blade saw method, the cost of consumable materials per wafer is estimated to be 60 yen, 85 yen, and 70 yen, respectively. Furthermore, in terms of the total cost including ingot cutting loss (slice loss), the platen type, the wire saw type, and the internal blade type are the most popular.

Furthermore, when the performance of the various types of wire saws, blade saws, and internal blades described above are compared, the results can be evaluated as shown in Table 1.

Table 1 C: Bad Therefore, as can be seen from the evaluation shown in Table 1,
In the cutting method using a wire saw, if the productivity, yield, and cost of consumable materials are improved, wafers can be cut and manufactured with high quality and at low cost.

The present invention was developed in view of the above circumstances, and has a long life with less wear and can significantly shorten cutting time. Therefore, it can be suitably used as a cutting jig in a wire saw-type cutting method. The object of the present invention is to provide a cutting wire that can effectively solve the problems of productivity, yield, and consumable material costs in a one-way wire saw method.

- 〇For the divination The present inventors have carried out intensive studies to achieve the above objective, and as a result, we have found that Ni-Cr system, Fe-Ni system, Fe-Cr-Af
By using a cutting wire obtained by applying diamond coating to a wire base material such as L-based alloy or W or Mo metal as a cutting jig in a wire saw type, high-speed feeding is possible and slicing time is shortened. Furthermore, it was discovered that the amount of wear on the wire saw was reduced, making it possible to use it many times, and as a result, significant productivity improvements and cost reductions were achieved in wire saw-based cutting methods. , which led to the present invention.

Therefore, the present invention provides a cutting wire that has a diamond coating film on a wire base material and is suitably used as a wire saw type cutting jig.

The present invention will be explained in more detail below.

The cutting wire according to the present invention is formed by forming a diamond coating film on a wire base material.

Here, as the wire base material, piano wire, which is normally used as a cutting jig in the wire saw type, may not be able to withstand the temperature conditions when coating with a diamond film, so Ni-Cr, which has high heat resistance, is used as the wire base material. system, Fe
-Ni series, Fe-Cr-AQ series alloys, W, Mo metals, etc. are suitable.

Further, it is preferable that the diamond film coated on the wire base material is usually formed to have a thickness of 0.01 to 50%.

In this case, as a method of coating the wire with a diamond film, various conventionally well-known methods can be adopted, such as: ① generating a carbon positive ion beam by combining arc discharge and sputtering; The ion beam method accelerates this, focuses it further, and collides with the surface of the wire base material to precipitate diamond.■
Graphite, a wire base material, and hydrogen are placed in a sealed tube, and the graphite is placed in a high temperature part and the base material is placed in a low temperature part and sealed, and the hydrogen gas is dissociated by heat or electric discharge to generate atomic hydrogen, A chemical transport method that uses a disproportionation reaction to deposit diamond on the surface of a substrate. ■ Microwaves of 300 MHz or higher are introduced into a mixed gas of hydrogen gas and hydrocarbons to generate microwave plasma. A method may be adopted in which a wire base material is placed in plasma, hydrocarbons are decomposed, and diamond is precipitated on the surface of the base material.

Among these, the diamond coating film obtained by method (1) is particularly suitable for cutting because no carbon with a disordered structure is generated.

As mentioned above, the cutting wire of the present invention is effectively used as a cutting jig using a one-way wire saw. The conditions, etc. are the same as those of the conventional wire saw method, and the usual methods and conditions are adopted.

The cutting wire of the present invention has excellent wear resistance and has a longer lifespan than conventional wires, so that the frequency of jig replacement can be reduced and cutting time can be shortened.

5 The cutting wire of the present invention can be used not only for slicing silicon ingots to produce wafers, but also for cutting compound semiconductors, oxide single crystals/polycrystals, ceramics, glass, metals, etc. , demonstrate superior ability.

tU Harimasu Kaichi The cutting wire according to the present invention is Ni-Cr based.

By forming a diamond coating film on wire base materials such as Fe-Ni alloy, Fe Cr'AQ alloy, W, Mo metal, etc., it has less wear, has a long life, and can shorten cutting time. , cutting can be performed efficiently and cutting costs can be reduced.

Hereinafter, the present invention will be explained with reference to examples, but the present invention is not limited to the following examples.

〔Example〕

A cutting wire was produced by applying diamond coating to a nichrome wire using the diamond coating apparatus shown in FIG.

That is, FIG. 4 schematically shows an apparatus for decomposing hydrocarbons using microwave plasma to precipitate diamonds. In FIG. 4, 7 is a microwave transmitting device 8, an exhaust device 9,
Methane gas cylinder 10. The reactor was equipped with a hydrogen gas cylinder 11, and when diamond coating was applied to the surface of the nichrome wire 12 using this device, the exhaust device 9 was first activated to adjust the pressure inside the reactor 7 to 40 torr in advance. Next, 1 liter of hydrogen gas is added from the hydrogen gas cylinder 11.
Methane gas was flowed from the methane gas cylinder 10 at a flow rate of 0.00 d/min, and was supplied from the methane gas cylinder 10 into the reactor 7 through the conduit 13, while the microwave transmitter 8 was operated at a frequency of 900 MHz and IKW. Generated plasma. The nichrome wire 12 is passed through this plasma for 1 hour/hr.
A diamond coating film having a thickness of 5 mm was deposited on the nichrome wire 12. Note that the nichrome wire 12 is fed out from the nichrome wire source roller 14.

The nichrome wire was wound by a winding device 15. In addition, 16 in the figure is an alumina plate for induction heating.

Next, the diamond-coated nichrome wire is
Used as a cutting jig for the wire saw shown in the figure,
The cutting effect was evaluated by slicing the silicon ingot.

Note that the slicing conditions are as shown in Table 2.

Table 3 also shows the results of wafer manufacturing using the conventional wire saw method, blade saw method, and internal blade method.

Table 2 Note that the cutting wire used in the conventional one-wire saw type is piano wire for wire saws manufactured by Meiboku Kinzoku Kogyo Co., Ltd., and the blade used in the one-sided blade saw type is one made by Asahi Diamond Co., Ltd. [Suncut Super CAD-2U]. )
] was used, and an ID saw manufactured by DISCO was used for the inner peripheral blade method. In addition, the cutting conditions for the conventional wire saw type are: wire diameter 140, abrasive grain GC#1O00, and wire speed 120 m/min, and for the blade saw type, blade pitch is 0.75W + number of blades is 201. , abrasive grain GC#1O00, blade reciprocating speed 6
00 reciprocation/min, and in the case of the inner peripheral blade method, use a blade with a thickness of 130p and a peripheral speed of 1500 m/111i.
Cut with a feed rate of 60 mm/1 lin.

As shown in the results in Table 3, the diamond-coated wire of the present invention can increase the pressure applied to the wire to prevent wear, and therefore can slice at high speed. The number of wafers was 20 in the case of the one-type wire saw, but the number increased to 32 by using the wire saw of the present invention, and it was also confirmed that the wobbling of the wire was reduced and the dimensional accuracy of the wafer was improved. .

Furthermore, compared to the conventional wire saw method, the wire saw method using the wire of the present invention can reduce the cost per wafer by 30 yen, and 5 yen less than the internal blade method. It's 15 yen cheaper than a blade saw. Moreover, when time savings such as slice loss and installation setup are included, considerable cost reductions have been achieved.

[Brief explanation of the drawing]

Fig. 1 is a schematic diagram illustrating a cutting method using a wire saw method, Fig. 2 is a schematic diagram explaining a cutting method using a blade saw method, and Fig. 3 is a schematic diagram explaining a cutting method using an internal blade method. FIG. 4 is a schematic diagram showing an example of a diamond coating device. 1... Ingot, 4... Wire.

Claims (1)

[Claims] 1. A cutting wire characterized in that a diamond coating film is formed on a wire base material. 2. The wire base material is Ni-Cr based, Fe-Ni based and F
The cutting wire according to claim 1, which is made of a wire selected from an e-Cr-Al alloy and W and Mo metals. 3. The cutting wire according to claim 1 or 2, which is used for slicing crystal ingots.