JPH0366106B2 - - Google Patents

Description

[Detailed description of the invention]

INDUSTRIAL APPLICATION FIELD This invention relates to a method for cutting so-called brittle materials such as semiconductor materials, magnetic materials, and ceramics using a wire and a machining fluid containing abrasive grains or a cutting fluid containing an acid (hereinafter referred to as machining fluid). Prior Art and Its Problems One method for cutting brittle materials such as semiconductor materials is a wire saw that cuts by supplying a machining fluid containing abrasive grains while sliding a wire against a member to be cut. To explain the cutting method, as shown in an example in FIG. 4, parallel wires 2 are stretched at predetermined intervals between a plurality of grooved rollers 1, and the member to be cut 3 is pressed against the wire portions. While running the wire, the member to be cut 3
A machining fluid is supplied to the part to be cut from a machining fluid supply porous nozzle 4 provided above the part to be cut. 5 is a table for pushing up the member to be cut. The machining fluid supply multi-hole nozzle 4 has a large number of holes drilled at regular intervals along the workpiece 3, and the machining fluid drops from each hole in a linear fashion onto the workpiece. supply is becoming available. However, in this method of cutting using a machining fluid supply nozzle, the machining fluid flows along the narrow groove cut by the wire into the sliding contact area between the workpiece and the wire due to gravity or capillary action. Therefore, as the groove becomes deeper, it takes more time to reach the wire sliding contact portion, and there is no choice but to limit the amount. Furthermore, there is no guarantee that all wire sliding contact areas will be uniformly supplied. In wire sliding contact areas where machining fluid is insufficiently supplied, roughness increases, and in extreme cases, flaws called saw marks occur on the cut surfaces. At this time, the wires were worn to a large extent, and troubles such as wire breakage occurred. Purpose of the Invention The present invention was made in order to solve the above-mentioned conventional problems, and it is possible to improve cutting efficiency and machining accuracy by constantly supplying machining fluid uniformly and sufficiently, and to improve wire wear. The purpose of this study is to propose a method for cutting brittle materials that can significantly reduce the Structure of the Invention The method for cutting a brittle material according to the present invention uses a hopper-type slit nozzle having a slit-shaped outlet, and positions the slit nozzle at a position where the vertical distance from the wire is maintained and where the wire and the member to be cut begin sliding contact. The gist of this is to cut the wire while moving it parallel to the wire so as to maintain a substantially constant distance from the slit nozzle. In this invention, the reason why cutting is performed while moving the slit nozzle as described above is as follows. The amount of machining fluid that is supplied from the slit nozzle by dropping onto the wire row is constant, but by the time it reaches the workpiece, it falls and scatters from the wire row, so the machining fluid reaches the workpiece while adhering to the wire. The amount decreases as the distance from the slit nozzle to the workpiece to be cut increases. On the other hand, in order to prevent the generation of saw marks, it is necessary to bring a sufficient amount of machining fluid to the workpiece to be cut, and it is desirable to always keep the distance between the slit nozzle and the workpiece to be cut short.
For this reason, in the present invention, the slit nozzle cuts while maintaining a constant distance between the member to be cut, the wire, and the sliding portion as described above. Of course, if the member to be cut has a rectangular cross section, there is no need to move the slit nozzle. The method of this invention will be explained below based on the drawings. 1 and 2 show an example of an apparatus for carrying out the method of the present invention, in which a machining fluid supply multi-hole nozzle 4 is located below a machining fluid supply multi-hole nozzle 4 in which a number of holes are bored at regular intervals along a workpiece 3. , the slit-shaped outlet 6-
1 is attached to a slide guide 8 via a support jig 7 so as to be movable parallel to the wire. The mounting structure is such that both side walls of the hopper-type slit nozzle 6 are mounted on side struts 7-1 of a support jig 7, and the slide guide 8 provided below the wire portion that slides into contact with the workpiece 3 is supported. The jig 7 is fitted and supported so as to be horizontally movable parallel to the wire by a concave-convex fitting method. As a means for moving the hopper type slit nozzle 6, for example, a ball screw 9 is screwed into a nut portion 7-2 protruding from the lower surface of the support jig 7, and the ball screw is connected to the reversible motor 1 through a belt 10.
1 can be used. In the case of a wire saw that cuts a wire by running it in one direction, the machining fluid supply device is provided on the side where the wire enters toward the member 3 to be cut. On the other hand, in the case of a wire saw that cuts the wire by running it back and forth, the side where the wire enters changes alternately on the left and right sides of the workpiece 3, so it should be installed on both the left and right sides of the workpiece 3. is desirable. Effects of the Invention FIG. 3 shows an embodiment of the present invention in which a wire 2 is run in one direction to cut a cut member 3 having a circular cross section.
Indicates the situation when disconnecting. As described above, the wires 2 form a wire row with a predetermined pitch, and the slit nozzle 6-1 of the hopper 6 has a width that allows the machining liquid to be applied to all the wires 2 in the wire row. Machining fluid is supplied to the hopper 6 from the porous nozzle 4. This multi-hole nozzle 4 is fixed in space, and even if the hopper 6 moves in the longitudinal direction of the wire 2, the machining liquid will not flow into the hopper 6.
The length 1 of the hopper 6 is set so that the hopper 6 is supplied with the desired amount. Of course, the multi-hole nozzle 4 may be fixed to the hopper 6 and movable together with the hopper 6 in the longitudinal direction of the wire 2. FIG. 3A shows a state in which the top of the member to be cut 3 has come into contact with the wire 2 and cutting has begun. The distance d between the slit nozzle 6-1 and the apex of the workpiece 3 is 30
It is desirable to set it to approximately 60 mm to 60 mm. This is because if d is too small, the machining fluid that has fallen from the slit nozzle 6-1 will scatter when it hits the member to be cut 3, and the amount of machining fluid that will adhere to the wire will not be stable. Further, the g between the slit nozzle 6-1 and the wire 2 is preferably about 10 to 30 mm; if this is too large, the machining fluid hits the wire strongly, resulting in a large amount of machining fluid falling from the wire. Furthermore, the wire moves and the accuracy of the cut surface deteriorates. FIG. 3B shows a state in which the cutting has progressed to a certain extent, and at this point the hopper 6 has retreated to the left and the distance d between the slit nozzle 6-1 and the circumferential surface of the workpiece 3 is maintained. Incidentally, since the hopper 6 is moved horizontally, g is also maintained between the slit nozzle 6-1 and the wire. FIG. 3C shows the point in time when the largest diameter portion of the member 3 to be cut is being cut, and the hopper 6 is at the most retreated position from the member 3 to be cut. As the cutting progresses further, the motor 1 shown in Fig.
1 and move the hopper 6 to the right as shown in FIG. 3D. FIG. 3E shows a state in which the dummy material 7 adhesively fixed between the workpiece 3 and the push-up table 5 has begun to be cut. From this point on, the hopper 6 is kept stationary without moving horizontally, and the workpiece Stop pushing up when 3 is completely cut. When cutting is completed, the supply of machining fluid is stopped and the hopper type slit nozzle 6 is separated from the workpiece 3 by the motor 11. As mentioned above, the method of the present invention uses a hopper-type slit nozzle that discharges machining liquid in the form of a water curtain, and supplies the machining liquid to the sliding contact area between the workpiece and the wire while moving it along the circumferential surface of the workpiece. Since this is a cutting method, the machining liquid is uniformly and sufficiently supplied to the cut portion of the workpiece. Therefore, there is no occurrence of scratches (saw marks) caused by insufficient supply of machining fluid, thereby improving cutting accuracy, and cutting efficiency is also significantly improved due to the stable supply of machining fluid. Furthermore, the effect of reducing wire wear is significant, and wire breakage accidents are almost eliminated. Example 1 Using the machining fluid supply device shown in Fig. 1, a φ4" Si single crystal was cut with a wire saw under the following conditions. The results were then cut using the same wire saw with a conventional multi-hole nozzle shown in Fig. 4. Table 1 shows a comparison with cutting using the machining fluid supply method. Cutting conditions Wire speed: Maximum 400 m/min, unidirectional running method Machining fluid: GC # 800 and lap oil mixture Number of wafers cut: 150 wafers

[Table] Example 2 The results of cutting a φ5" Si single crystal under the same cutting conditions using the same wire saw and machining fluid supply device as in Example 1 are compared with those cut using the conventional machining fluid supply method using a multi-hole nozzle. are shown in Table 2.

[Table] As is clear from Tables 1 and 2 above,
By the method of this invention, both the cutting precision and cutting efficiency of the object to be cut have been greatly improved.

[Brief explanation of drawings]

FIG. 1 is a schematic side view showing an example of a device for carrying out the method of this invention, FIG. 2 is a front view of the same device, and FIG. 3 is an embodiment of the invention in which the wire is run in one direction. This is a schematic diagram showing the situation in which a workpiece with a circular cross section is cut using the following methods. A is a state in which the top of the workpiece is in contact with the wire and cutting has started, B is a state in which the cut has progressed to a certain extent, and C is a state in which the workpiece has been cut to a certain extent. Figure 2 shows the state in which the thickest diameter part is being cut, Figure 2 shows the state in which the machining fluid supply hopper is moving to the right, and Figure E shows the state in the final stage of cutting.
FIG. 4 is a schematic diagram showing a conventional cutting method. DESCRIPTION OF SYMBOLS 1... Groove roller, 2... Wire, 3... Member to be cut, 4... Porous nozzle, 5... Push-up table, 6...
...Hopper type slit nozzle, 7...Support jig,
8...Slide guide, 9...Ball screw, 11
……motor.

Claims (1)

[Claims] 1. A method of cutting a workpiece by supplying machining liquid to the sliding contact portion while bringing the workpiece into sliding contact with the wire, in which a hopper-type slit nozzle having a slit-shaped outlet is used, and the slit nozzle is set at a vertical distance from the wire. A method for cutting a brittle material, characterized in that the cutting is carried out while moving parallel to the wire so as to maintain a constant distance between the sliding contact start position of the wire and the member to be cut and the slit nozzle.