JP2011025347A - Method for machining metal plate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a new and improved method for machining a metal plate, reducing and dividing the metal plate into prescribed finished thickness by avoiding and sufficiently suppressing generation of burrs on a rear face side, even in the metal plate like a thin copper plate having high toughness. <P>SOLUTION: A groove formation process is performed to form a groove (18) deeper than the prescribed finished thickness (H) along a dividing line on one surface (16) of the metal plate (2) by a cutting blade (10). After the groove formation process, a protective tape sticking process is performed to stick a protective tape (T) to the one surface (16) of the metal plate (2). The metal plate (2) is then finished to the prescribed thickness (H) by turning the other surface (14) by a turning tool (22). <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a dividing method for reducing a metal plate to a predetermined finished thickness and dividing the metal plate along a dividing line.

  The division of a metal plate such as a copper thin plate used as a Peltier element substrate is generally performed by using a cutting blade in a cutting apparatus. As the cutting blade, a diamond-shaped diamond blade formed by sintering diamond abrasive grains or CBN (cubic boron nitride) abrasive grains with a resin bond, or a cemented carbide tool formed of cemented carbide is used. The However, when a metal plate is cut with a cutting blade, a metal burr having a size exceeding several hundred μm extends on the back side particularly in the case of a metal plate having high toughness such as a copper substrate.

  In general, in the division by cutting, the processing quality on the back surface side tends to deteriorate compared to the front surface. Therefore, as a technique for thinning and dividing a semiconductor wafer formed of a brittle material such as a silicon wafer, a tip dicing method that is expected to reduce chipping on the back side is widely performed (Patent Document 1). In such a tip dicing method, first, a cutting groove deeper than a target thickness is formed from the surface side on which the device is formed by an electroforming blade in which diamond abrasive grains are electrodeposited with a nickel-based bond layer. After that, a protective tape is attached to the front side of the semiconductor wafer, the protective tape side is brought into contact with the chuck table of the grinding device to hold the semiconductor wafer, and the semiconductor wafer is thinned with a grinding wheel until the target thickness is reached from the back side. The semiconductor wafer is divided into chips. As the grinding wheel, a sintered grinding wheel is used in which a diamond grinding grain is sintered by vitrified bond, resin bond, etc., and a segmented grinding wheel is fixed to the outer periphery of a circular base in an annular shape. . By repeating the self-generated blades of diamond abrasive grains, the brittle material can be ground satisfactorily and the occurrence of chipping in the divided chips can be sufficiently suppressed.

JP 2002-373870 A

  In the processing of the metal plate, it is intended to perform the above-described dicing method for the purpose of reducing metal burrs on the back side. However, if the flat surface of the metal plate is ground with the above-mentioned sintered grinding wheel, clogging or crushing of the abrasive grains occurs due to the metal. Unable to perform proper grinding.

  The present invention has been made in view of the above facts, and the main technical problem thereof is to avoid or sufficiently suppress the occurrence of burrs on the back side even when the metal sheet is a tough copper thin plate, It is to provide a new and improved method of processing a metal plate which can be reduced to a predetermined finished thickness and divided.

As a result of diligent examination and experiment, the inventor has formed a groove deeper than a predetermined finish thickness along a dividing line on one side of a metal plate, and then turned the other side of the metal plate with a turning tool to obtain a predetermined finish thickness. It has been found that the main technical problem can be achieved by carrying out the unique process of doing.
As used herein, the phrase “turning tool” means a tool with a tip that is formed entirely of diamond or other superhard material and has a turning edge defined at the boundary between the rake face and the flank face. .

According to the present invention, as a method of dividing the metal plate to achieve the main technical problem, the metal plate is reduced to a predetermined finished thickness and is divided along the dividing line,
A groove forming step of forming a groove deeper than a predetermined finished thickness along the dividing line on one side of the metal plate by a cutting blade;
After the groove forming step, a protective tape attaching step of attaching a protective tape to the one surface of the metal plate;
After the sticking step, turning the other side of the metal plate with a turning tool to turn the metal plate to the predetermined finished thickness,
A method for processing a metal plate is provided.

  Preferably, a resin filling step of filling a resin into the groove formed on one surface of the metal plate is performed after the groove forming step and before the attaching step.

  According to the inventor's experiment, according to the turning using a turning tool, even when the metal plate is a high toughness copper thin plate, the other surface of the metal plate is sufficiently satisfactorily turned to a predetermined finished thickness. Therefore, the occurrence of burrs on the back side can be avoided or sufficiently suppressed, and the metal plate can be reduced to a predetermined finished thickness and divided.

Sectional drawing which shows a groove | channel formation process. Sectional drawing which shows a protective tape sticking process. Sectional drawing which shows the turning process of 1st embodiment. The principal part perspective view of a turning tool. (A) Schematic which shows the initial position of a turning process. (B) Schematic which shows the end position of a turning process. Sectional drawing which shows the resin filling process. Sectional drawing which shows the turning process of 2nd embodiment.

  Hereinafter, a preferred embodiment of a metal plate processing method of the present invention will be described in more detail with reference to the accompanying drawings.

(Groove formation process)
The metal plate 2 is a circular or rectangular copper plate that becomes a substrate of the Peltier element after division, and has division lines (not shown) arranged in a lattice on one side. First, as shown in FIG. 1, a groove forming process is performed on the metal plate 2 by a cutting device. The configuration of the cutting device itself may be a well-known form disclosed in, for example, Japanese Patent Application Laid-Open No. 2008-262983, and detailed description thereof is omitted in this specification. The surface of the chuck table 4 has a porous chuck plate (not shown) and is connected to a vacuum suction source (not shown). By connecting the chuck table 4 to a vacuum suction source, the metal plate 2 placed on the surface of the chuck table 4 is sucked and held. Further, the chuck table 4 is disposed so as to be rotatable about a central axis extending in the vertical direction, and is disposed so as to be movable in the X-axis direction which is a direction perpendicular to the paper surface in FIG.

  A cutting means 6 is disposed above the chuck table 4. The cutting means 6 includes a spindle 8 having a rotation axis extending in the Y-axis direction that is a direction perpendicular to the X-axis direction (the left-right direction in FIG. 1), and this spindle 8 is a rotational drive source such as a motor (see FIG. (Not shown). A cutting blade 10 is mounted on the tip of the spindle 8 via a blade mount 12 perpendicular to the rotational axis. The cutting blade 10 is, for example, an annular resin blade obtained by sintering CBN (cubic boron nitride) abrasive grains using a resin powder as a binder, and has a thickness of, for example, 300 μm. The cutting means 6 is disposed so as to be movable up and down in the Z-axis direction which is a direction perpendicular to the holding surface of the chuck table 4. Further, the cutting means 6 is disposed so as to be movable in the Y-axis direction.

  As shown in FIG. 1, the metal plate 2 is sucked and held on the chuck table 4 with one side 16 thereof facing upward. The cutting blade 10 starts to rotate at a high speed, and the lower end of the cutting blade 10 is positioned at a position deeper than the predetermined finished thickness H on the dividing line. The chuck table 4 moves in the X-axis direction to form a groove 18 deeper than a predetermined finished thickness H along the dividing line. Thereafter, the cutting blade 10 is positioned on the next dividing line, and the groove 18 is formed in the same manner. In this way, when the grooves 18 are sequentially formed and the dividing lines are formed in a lattice shape, the chuck table 4 is rotated by 90 ° to similarly form the grooves 18, and all the metal plates 2 are formed. Grooves 18 are formed along the dividing lines (groove forming step). In the groove forming step, other cutting blades such as a cutting blade formed of a cemented carbide having tungsten carbide as a main component and cobalt as a binder may be used.

(Protective tape application process)
In 1st embodiment, after completion | finish of a groove | channel formation process, as shown in FIG. 2, the protective tape 19 is stuck on the single side | surface 16 in which the groove | channel 18 of the metal plate 2 was formed (protective tape sticking process). The protective tape 19 is composed of a base material and an adhesive layer laminated on one side of the base material, and the adhesive layer preferably has an ultraviolet curable strong adhesive force.

(Turning process)
A turning process is then performed. This turning process is a processing apparatus disclosed in Japanese Patent Laid-Open No. 2005-327838, which was developed as a processing apparatus for aligning the protruding heights of a large number of electrodes (bumps) disposed on the surface of a plate-like object. Can be carried out using As shown in FIG. 3, the machining apparatus includes a turning unit 22. The turning unit 22 includes a spindle 26 that is rotatable about a central axis extending in the Z-axis direction, that is, a vertical direction, and is movable up and down in the Z-axis direction, and a support wheel that is attached to the lower end of the spindle 26. 24 and a turning tool 28 fixed to the outer peripheral surface portion of the lower surface of the support wheel 24. As shown in FIG. 4, the turning tool 28 includes a shank 30 and a diamond tip 32 that is fixed to the front end surface of the shank 30 and protrudes from the lower end of the shank 30. The shank 30 is fixed to the lower surface of the support wheel 24 in an appropriate manner such as bolting, and the diamond tip 32 is fixed to the shank 30 in an appropriate manner such as brazing. A diamond tip 32 made of diamond or other super hard material has a rake face 34 extending substantially vertically and a flank 33 having a predetermined flank angle θ of 10 ° or more with respect to the horizontal. A sharp turning edge 35 having a width W is defined at the boundary between the surface 34 and the flank 33. The cutting edge 35 is aligned with the radial direction of the support wheel 24.

  Below the turning unit 22, a chuck table 20 is disposed so as to be movable in the Y-axis direction (left and right in FIG. 3) indicated by an arrow A. The chuck table 20 has a porous chuck plate (not shown) and is connected to a vacuum suction source (not shown). By connecting the chuck table 20 to a vacuum suction source, the metal plate 2 placed on the surface of the chuck table 20 is sucked and held.

  Continuing the description of the turning process, as shown in FIG. 3, the metal plate 2 is sucked and held on the chuck table 20 with the other surface 14 of the metal plate 2 facing upward. Next, the turning unit 22 is rotated at a rotational speed of 3000 to 5000 rpm. Then, the turning unit 22 is lowered, and the diamond tip 32 is positioned at a predetermined cutting position where the predetermined cutting thickness of the metal plate 2 is Hmm, and the chuck table 20 is positioned at the initial position shown in FIG. The turning unit 22 rotates clockwise in FIG. 5A, and the turning edge 35 of the diamond tip 32 is fixed in a direction perpendicular to the rotation direction. When the width W μm of the rake face 34 of the diamond tip 32 is 50 μm, for example, when the chuck table 20 holding the metal plate 2 by suction is moved to the right in FIG. 5 at a feed rate slower than 2.5 mm / s, Flat turning is possible. The feed speed of the chuck table 20 is set so that the relative moving distance when the turning tool 28 makes one rotation is smaller than the width W μm of the turning edge 35 of the diamond tip 32. As shown in FIG. 3, the metal plate 2 is thinned to a predetermined finished thickness Hmm, and a groove 18 having a depth equal to or larger than the predetermined finished thickness Hmm is formed, so that the metal plate 2 is divided from the turned portion. . The chuck table 20 moves further to the right and moves to the end position in FIG. 5B where the diamond tip 32 is detached from the chuck table 20. As a result, the metal plate 2 is turned to a predetermined finished thickness Hmm by the diamond tip 32 that rotates as the turning unit 22 rotates, and is divided along the groove 18. The divided chips are picked up from the holding table 19 and used in the next process.

  Next, the second embodiment will be described. In the second embodiment, a resin filling step is performed after the groove forming step. In the groove forming step, a groove 18 is formed on one surface 16 of the metal plate 2 by the same method as in the first embodiment. Next, as shown in FIG. 6, the metal plate 2 is sucked and held on the rotary table 36 of a spin coater having a known structure with one side 16 facing upward. The rotary table 36 is rotated at a predetermined speed, and a water-soluble resin 40 such as PVA is dropped from the nozzle 38 disposed above the rotary table 36 near the center of the metal plate 2. The resin 40 spreads to the outer periphery while entering the groove 18 due to the centrifugal force generated by the rotation of the turntable 36, and as a result, all the grooves 18 are filled with the resin 40 (resin filling step).

  After the resin 40 is dried, the protective tape 19 is attached to the one surface 16 side of the metal plate 2 (protective tape attaching step). Thereafter, similarly to the first embodiment, the metal plate 2 is sucked and held on the chuck table 20 of the processing apparatus with the other surface 14 of the metal plate 2 facing upward, and the turning process is performed. At this time, since the groove 18 is filled with the resin 40, the generation of burrs extending into the groove 18 during turning by the turning tool 28 can be sufficiently suppressed. The metal plate 2 is divided | segmented by removing the resin 40 with a pure water etc. after a turning process.

2 Metal plate 4 Chuck table (cutting machine)
6 Cutting means 18 Groove 19 Protective tape 20 Chuck table (processing device)
22 Turning unit 28 Turning tool 32 Diamond tip 33 Flank face 34 Rake face 35 Turning edge H Predetermined thickness W Rake face width

Claims (2)

A processing method for reducing a metal plate to a predetermined finished thickness and dividing along a dividing line,
A groove forming step of forming a groove deeper than the predetermined finished thickness along the dividing line on one side of the metal plate by a cutting blade;
After the groove forming step, a protective tape attaching step of attaching a protective tape to the one surface of the metal plate;
After the sticking step, turning the other side of the metal plate with a cutting tool to turn the metal plate to the predetermined finished thickness,
The metal plate processing method characterized by including.   The metal plate processing method according to claim 1, wherein a resin filling step of filling a resin into the groove formed on one side of the metal plate is performed after the groove forming step and before the attaching step.

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