JP5850758B2 - Grinding method - Google Patents

Description

  The present invention relates to a grinding method for grinding a long workpiece.

  A semiconductor wafer in which a number of devices such as IC and LSI are formed on the surface, and each device is partitioned by a line to be divided (street), the back surface is ground by a grinding machine and processed to a predetermined thickness. A dividing line is cut by a cutting device (dicing device) to be divided into individual devices, and the divided devices are used for various electric devices such as mobile phones and personal computers.

  A grinding apparatus for grinding a workpiece such as a wafer can rotate a grinding wheel in which a chuck table for holding the workpiece and a grinding wheel for grinding the workpiece held on the chuck table are annularly arranged. A grinding unit for supporting, a grinding feed mechanism for grinding and feeding the grinding wheel in a direction approaching the workpiece, and a chuck table moving mechanism for linearly moving the chuck table in a direction approaching and moving away from the grinding unit. The workpiece can be ground to a predetermined thickness.

  Workpieces to be ground with a grinding machine are mostly wafer-shaped workpieces such as semiconductor wafers and optical device wafers, but bar-shaped glass and resin used for optical components, for example, bar-shaped PZPs that become ultrasonic vibrators A grinding device is also used to thin a long ceramic workpiece such as (lead zirconate titanate) to a predetermined thickness.

  The long workpiece is adhered to a base made of a metal such as SUS with wax or the like, and fixed to a holding table of a grinding apparatus by screwing or the like. Here, when the combination of the holding table of the grinding apparatus and the base screwed to the holding table is referred to as a holding unit that holds the workpiece, it is linear in the Y-axis direction approaching the grinding unit without rotating the holding unit. A long workpiece is ground by a grinding wheel positioned at a predetermined height while being moved. At this time, grinding of the long workpiece is performed while the grinding wheel is positioned at a predetermined height without being fed to the long workpiece.

JP 10-187207 A

  By the way, when a foreign object is inserted between the base and the holding table when holding the long workpiece by the holding unit of the grinding apparatus, the upper surface of the workpiece is inclined from one end to the other end. When a long workpiece is ground with a grinding wheel positioned at a predetermined height in this state, the thickness of the ground long workpiece is not uniform, which causes a problem.

  The present invention has been made in view of the above points, and an object of the present invention is to provide a long workpiece in which the upper surface of the long workpiece held on the holding unit is inclined. It is to provide a grinding method capable of grinding to a uniform thickness.

  According to the present invention, there is provided a grinding method for grinding a long workpiece by a grinding means having a grinding wheel, the holding step for holding the long workpiece by the holding means, and the long length held by the holding means. Measure the upper surface height position of one end and the other end of the workpiece, detect the inclination direction of the upper surface of the long workpiece and detect the height position of the one end and the other end and the long side of the long workpiece An inclination detection step for detecting the inclination from the length, and after the inclination detection step, the one end of the long workpiece detected by the inclination detection step by rotating the holding means in the horizontal direction and the other The lower end of the height position is directed to the grinding means, and the longitudinal direction of the long workpiece held by the holding means and the movement in which the holding means moves closer to the grinding means in the horizontal direction. Rotating step for holding means to coincide with direction, and holding means After carrying out the rolling step, the grinding means having a rotating grinding wheel is positioned at a predetermined height, and the holding means holding the long workpiece is moved closer to the grinding means in the horizontal direction. And a grinding step for grinding the upper surface of the long workpiece by the step of detecting the inclination while moving the holding means in the horizontal direction relative to the grinding means. There is provided a grinding method characterized in that, based on the degree of inclination of the upper surface of the long workpiece, the grinding means is continuously raised to perform grinding following the inclination of the upper surface of the long workpiece.

  According to the grinding method of the present invention, after detecting the inclined state of the surface of the long work piece held by the holding means, the long work piece is ground while changing the height position of the grinding means along the inclination. Since the upper surface of the long workpiece is ground by moving it linearly, the long workpiece can be ground to a uniform thickness.

It is a perspective view of a grinding device suitable for carrying out the grinding method of the present invention. It is a side view which shows an inclination detection step. It is a side view explaining an inclination. It is a top view explaining an inclination direction. It is a top view explaining a holding means rotation step. It is a side view which shows a grinding step.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Referring to FIG. 1, an external perspective view of a grinding apparatus 2 suitable for carrying out the grinding method of the present invention is shown. Reference numeral 4 denotes a base of the grinding apparatus 2, and a column 6 is erected on the rear side of the base 4. A pair of guide rails 8 extending in the vertical direction is fixed to the column 6.

  A grinding unit (grinding means) 10 is mounted along the pair of guide rails 8 so as to be movable in the vertical direction. The grinding unit 10 includes a spindle housing 12 and a support portion 14 that holds the spindle housing 12, and the support portion 14 is attached to a moving base 16 that moves up and down along a pair of guide rails 8. Yes.

  The grinding unit 10 includes a spindle 18 rotatably accommodated in a spindle housing 12, a motor 20 that rotationally drives the spindle 18, a wheel mount 22 fixed to the tip of the spindle 18, and a detachable attachment to the wheel mount 22. And a mounted grinding wheel 24.

  The grinding apparatus 2 includes a grinding unit feed mechanism 34 including a ball screw 30 and a pulse motor 32 that move the grinding unit 10 in the vertical direction along the pair of guide rails 8. When the pulse motor 32 is driven, the ball screw 30 rotates and the moving base 16 is moved in the vertical direction.

  A recess 4a is formed on the upper surface of the base 4, and a holding table mechanism 36 is disposed in the recess 4a. The holding table mechanism 36 has a holding table 38 and is moved in the Y-axis direction between a workpiece attaching / detaching position A and a grinding position B facing the grinding unit 10 by a moving mechanism (not shown).

  The holding table 38 has a rectangular shape, and screw holes 40 are formed at four corners. The holding table 38 is configured to be movable and rotatable in the Y-axis direction. Reference numeral 42 denotes a bellows. An operation panel 44 is provided on the front side of the base 4 so that an operator of the grinding apparatus 2 can input grinding conditions and the like.

  Reference numeral 11 denotes a bar-shaped long workpiece to be ground by the grinding method of the present invention, which is bonded to a base 50 made of, for example, SUS (stainless steel) with wax or the like and held by the holding table 38 of the grinding apparatus 2. Mounted on top. The long workpiece 11 is made of ceramic such as bar-shaped PZT (lead zirconate titanate) that becomes an ultrasonic vibrator, bar-shaped glass used for optical parts, resin, and the like.

  The base 50 has a rectangular shape corresponding to the shape of the holding table 38, and mounting holes 52 are formed at its four corners. In order to grind the long workpiece 11 with the grinding device 2, the long workpiece 11 is fixed to the base 50, and the base 50 is further screwed to the holding table 38, whereby the long workpiece 11 is fixed. 11 is fixed on the holding table 38.

  At this time, when the base 50 is screwed to the holding table 38 with foreign matter 13 such as dust (see FIG. 2) sandwiched between the base 50 and the holding table 38, as shown in FIG. The workpiece 11 is held on the holding table 38 while being inclined from the horizontal state. In this specification, since the long workpiece 11 is held on the holding table 38 via the base 50, the combination of the base 50 and the holding table 38 is referred to as a holding unit.

  Instead of the embodiment in which the base 50 is screwed to the holding table 38, a holding table having a holding surface of the same size as the base 50 may be prepared, and the base 50 may be sucked and held by the holding table. .

  In the grinding method of the present invention, first, a holding step of holding the long workpiece 11 by the holding table 38 positioned at the workpiece attaching / detaching position A is performed. That is, the base 50 on which the long workpiece 11 is fixed with wax or the like is fixed to the holding table 38 by screwing.

  Next, as shown in FIG. 2, the height position detector 54 measures the upper surface height positions of the one end 11 a and the other end 11 b of the long workpiece 11 held by the holding table 38. As the height position detector 54, for example, a commercially available ultrasonic height position detector can be adopted.

  Or you may make it measure the upper surface height position of the elongate workpiece 11 with a laser-type height position detector and a contact-type height position detector. Reference numeral 13 denotes a foreign object sandwiched between the holding table 38 and the base 50.

  As shown in FIG. 3, if the height difference between the one end 11 a and the other end 11 b measured by the height position detector 54 is h, the height difference h and the long side of the long workpiece 11 From the length L, the inclination of the long workpiece 11 held by the holding table 38 can be detected. Further, as shown in FIG. 4, an inclination detecting step for detecting an inclination direction A from the Y-axis direction of the long workpiece 11 held by the holding table 38 is performed.

  In the inclination detection step, the inclination direction A of the upper surface of the long workpiece 11 held by the holding table 38 is detected, the height positions of the one end 11a and the other end b of the long workpiece 11 and the long workpiece. 11, after detecting the degree of inclination from the length L of the long side 11, the holding table 38 is rotated in the horizontal direction to detect the height of the one of the long ends 11 a and the other end 11 b detected in the inclination detecting step. The lower position is directed to the grinding unit 10 and, as shown in FIG. 5, the longitudinal direction of the long workpiece 11 held by the holding table 38 is in the Y-axis direction, that is, the holding table 38 is connected to the grinding unit 10. The holding table rotation step is performed to match the moving direction (arrow Y1 direction in FIG. 5) that moves close to the horizontal direction.

  After performing the holding table rotation step, a grinding step for grinding the upper surface of the long workpiece 11 is performed. In this grinding step, the long workpiece 11 is held via the base 50 by the holding table 38 of the grinding apparatus as shown in FIG. In FIG. 6, the grinding wheel 24 includes an annular wheel base 26 and a plurality of grinding wheels 28 that are annularly fixed to the free end of the wheel base 26.

  In this grinding step, for example, the grinding unit 10 having the grinding wheel 24 that rotates at a high speed such as 6000 rpm is positioned at a predetermined height position, and the holding table 38 that holds the long workpiece 11 is placed on the grinding unit 10. Move in the horizontal direction as indicated by arrow Y1.

  Then, based on the degree of inclination of the upper surface of the long workpiece 11 detected in the inclination detecting step, the holding table 18 is moved in the direction of the arrow Y1 while the grinding unit 10 is continuously raised, whereby the long workpiece The upper surface of 11 is ground following the detected inclination.

  For example, if it is possible to grind the upper surface of the long workpiece 11 by 5 μm by one grinding, the above-described grinding step is repeated a plurality of times, so that the long workpiece 11 is uniform from one end 11a to the other end 11b. It can be ground to the desired thickness.

  In the grinding step of the present invention, unlike the ordinary grinding method in which the workpiece is ground while the grinding wheel 24 is ground and fed downward by the grinding feed mechanism 34 at a predetermined grinding feed speed, the grinding wheel 24 is moved to a predetermined height. After being positioned at this position, grinding is carried out while continuously raising the grinding wheel 24 based on the degree of inclination of the upper surface of the long workpiece 11 detected in the inclination detecting step. At this time, the holding table 38 is not rotated but is ground while moving linearly in the Y-axis direction.

2 Grinding device 10 Grinding unit 11 Long workpiece 13 Foreign matter 24 Grinding wheel 28 Grinding wheel 38 Holding table 40 Screw hole 50 Base 52 Mounting hole 54 Height position detector

Claims (2)

A grinding method for grinding a long workpiece with a grinding means having a grinding wheel,
A holding step for holding the long workpiece by a holding means;
The upper surface height position of one end and the other end of the long workpiece held by the holding means is measured, the inclination direction of the upper surface of the long workpiece is detected, and the height positions of the one end and the other end are detected. An inclination detecting step for detecting the inclination from the length of the long side of the long workpiece;
After the inclination detection step, the holding means is rotated in the horizontal direction, and the lower one of the one end and the other end of the long workpiece detected at the inclination detection step is the grinding means. And a holding means rotating step in which the longitudinal direction of the long workpiece held by the holding means coincides with the moving direction in which the holding means moves closer to the grinding means in the horizontal direction;
After carrying out the holding means rotating step, the grinding means having a rotating grinding wheel is positioned at a predetermined height position, and the holding means holding the long workpiece is approached horizontally with respect to the grinding means. A grinding step for grinding the upper surface of the long workpiece by moving the workpiece,
In the grinding step, the grinding means is continuously moved based on the inclination of the upper surface of the long workpiece detected in the inclination detecting step while moving the holding means in the horizontal direction relative to the grinding means. And grinding according to the inclination of the upper surface of the long workpiece.   The grinding method according to claim 1, wherein the long workpiece is made of ceramic stuck on a base.

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