JP2016002606A - Grinding device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a grinding device capable of measuring the thickness of workpieces with probes being in contact with top faces of the workpieces stably, even when multiple workpieces are simultaneously held and ground.SOLUTION: The grinding device includes: holding means having a holding surface for holding workpieces W; grinding means for grinding rear surfaces WR of the workpieces W held by the holding means; and a height measuring unit 40 for measuring the height of the rear surfaces WR of the workpieces W, ground by the grinding means. The height measuring unit 40 includes two probes 43 of which contact points to come in contact with the rear surfaces WR of the workpieces W are provided at the same height position. The two probes 43 are disposed side by side along a circumference C around a rotation axis A of the holding means as the center, and provided so as to be spaced apart from each other at an interval W1 longer than an interval W2 in a circumferential direction of the workpieces W adjacent to each other.

Description

  The present invention relates to a grinding apparatus for grinding a workpiece while measuring the upper surface height of the workpiece.

  When various types of workpieces are thinned and finished to a desired thickness, grinding is performed while measuring the thickness of the workpiece, and the grinding is terminated when the desired thickness is reached. As a method of measuring the thickness of the workpiece, the contact of the thickness measuring instrument is brought into contact with the surface of the workpiece and the surface of the holding table that holds the workpiece, and the difference in height is obtained. A contact-type measuring method for obtaining the thickness of the workpiece from the difference value is known (for example, see Patent Document 1).

  On the other hand, a wafer as a workpiece formed of sapphire, gallium nitride (GaN), or the like has a diameter smaller than that of a normal wafer. For grinding a wafer with such a small diameter, a technique has been proposed in which a plurality of wafers are held on the same holding surface of one holding table and the plurality of wafers are ground simultaneously, thereby shortening the time required for grinding. (For example, refer to Patent Document 2).

JP 2000-006018 A JP 2012-101293 A

  When grinding multiple wafers at the same time, if you try to grind while contacting the contact of the thickness measuring instrument to the surface of the workpiece as described above, the contact will get caught between the rotating small-diameter workpiece. There is a problem that the height from the holding surface of the workpiece cannot be measured stably.

  An object of the present invention is to provide a grinding apparatus capable of measuring the thickness of a workpiece by stably contacting a top surface of the workpiece even when holding and grinding a plurality of workpieces simultaneously. Is to provide.

  In order to solve the above-mentioned problems and achieve the object, a grinding apparatus according to the present invention comprises a holding means having a holding surface for holding a workpiece, and a workpiece held by the holding means. A grinding device comprising: grinding means for grinding an upper surface of the workpiece; and a height measuring device for measuring the height of the upper surface of the workpiece ground by the grinding means, wherein the holding means comprises a plurality of A holding surface that holds the workpiece and is larger than the size of the workpiece, and is rotatable about a rotation axis that is orthogonal to the holding surface and passes through the center of the holding surface; A plurality of workpieces are held in a circumferential direction on a circumference around the rotation axis on a holding surface, and the height measuring device has a contact point that contacts the upper surface of the workpiece at the same height position. Provided with two measuring needles, and the two measuring needles have a rotational axis of the holding means. When measuring a plurality of workpieces, the measurement is performed in parallel when the plurality of workpieces are arranged in parallel along the circumference of the center and spaced apart from each other by an interval larger than the circumferential interval between adjacent workpieces. When the needle is positioned between the plurality of workpieces, the other measuring needle contacts the upper surface of one of the plurality of workpieces to constantly measure the height position of the workpiece. Features. Note that the circumferential interval between adjacent workpieces in claim 1 refers to the interval between adjacent workpieces when the workpieces are arranged at equal intervals in the circumferential direction. When the workpieces are not arranged at equal intervals in the circumferential direction, it refers to the interval between the most distant workpieces among the intervals between adjacent workpieces.

  According to the grinding apparatus of the present invention, two measuring needles are provided, and the two measuring needles are arranged in parallel along the circumference around the rotation axis of the holding means, and more than the circumferential interval between adjacent workpieces. They are spaced apart by a large distance. For this reason, when one measuring needle is positioned between a plurality of workpieces during grinding, the other measuring needle always comes into contact with the upper surfaces of the plurality of workpieces and can be measured. Therefore, even when holding and grinding a plurality of workpieces at the same time, the measuring needle does not fall or get caught between the workpieces, and the measuring needle can be stably held on the upper surface of the workpiece. The thickness of the workpiece can be measured by contacting the

Drawing 1 is an appearance perspective view showing the composition of the grinding device concerning an embodiment. FIG. 2 is a perspective view of a holding unit and a height measuring device of the grinding apparatus according to the embodiment. FIG. 3 is a perspective view of a height measuring instrument and a plurality of workpieces of the grinding apparatus according to the embodiment. FIG. 4 is a plan view of a height measuring device and the like of the grinding apparatus according to the embodiment and a plurality of workpieces. FIG. 5 is a side view of a height measuring instrument and a plurality of workpieces of the grinding apparatus according to the embodiment.

  DESCRIPTION OF EMBODIMENTS Embodiments (embodiments) for carrying out the present invention will be described in detail with reference to the drawings. The present invention is not limited by the contents described in the following embodiments. The constituent elements described below include those that can be easily assumed by those skilled in the art and those that are substantially the same. Furthermore, the structures described below can be combined as appropriate. Various omissions, substitutions, or changes in the configuration can be made without departing from the scope of the present invention.

  A grinding apparatus according to an embodiment of the present invention will be described with reference to FIGS. FIG. 1 is an external perspective view showing a configuration of a grinding apparatus according to the embodiment, FIG. 2 is a perspective view of holding means and a height measuring device of the grinding apparatus according to the embodiment, and FIG. FIG. 4 is a perspective view of a height measuring instrument and a plurality of workpieces of the grinding apparatus according to the embodiment, and FIG. 4 is a plan view of the height measuring instrument and the like of the grinding apparatus according to the embodiment and a plurality of workpieces. FIG. 5 is a side view of a height measuring instrument and a plurality of workpieces of the grinding apparatus according to the embodiment.

  A grinding apparatus 1 according to the present embodiment is an apparatus that performs grinding (corresponding to processing) on a workpiece W (shown in FIG. 3). Here, in the present embodiment, the workpiece W to be processed is a disk-shaped semiconductor wafer or optical device wafer having a base material of silicon, sapphire, gallium nitride (GaN), or the like. The workpiece W is divided into a plurality of regions by, for example, scheduled dividing lines called streets formed in a lattice pattern on the surface WS, and devices are formed in these partitioned regions. As shown in FIG. 3, the workpiece W is adhered to the holding member M, and a plurality of the workpieces W are held on the holding member M, and the back surface WR on the back side of the surface WS (FIG. 3 and FIG. 4). Are ground by the grinding wheel 26. In the present embodiment, the holding member M is formed in a disk shape, and the five workpieces W are arranged on the outer edge of the holding member M at equal intervals in the circumferential direction.

  As shown in FIG. 1, the grinding apparatus 1 includes a holding unit 10, a grinding unit 20, a processing feed unit 30, a height measuring device 40 (shown in FIG. 2), a control unit 100, and the like.

  The holding means 10 has a holding surface 10a on which the surface WS of the workpiece W is placed via the holding member M and sucks and holds the plurality of workpieces W placed thereon. As shown in FIG. 2, the holding means 10 has a disk shape in which a portion constituting the holding surface 10a is made of porous ceramic or the like, and is connected to a vacuum suction source (not shown) via a vacuum suction path (not shown). The workpiece W placed on the surface 10a is held by being sucked through the holding member M.

  That is, the holding means 10 has a holding surface 10a formed in a size larger than the size of the workpiece W. The holding means 10 is moved in the Y-axis direction by a holding means moving means (not shown) over a processing position below the grinding means 20 and an attaching / detaching position spaced from the bottom of the grinding means 20. The holding means 10 is centered on a rotation axis A (indicated by a one-dot chain line in FIGS. 2 and 3) that is perpendicular to the holding surface 10a and that passes through the center of the holding surface 10a. As rotatable. The holding means 10 holds the plurality of workpieces W on the holding surface 10a via the holding member M, so that the plurality of workpieces W on the circumference around the rotation axis A on the holding surface 10a. Are held at equal intervals in the circumferential direction.

  The processing feeding means 30 moves the grinding means 20 in parallel with the Z axis in a direction approaching and separating from the holding surface 10a. The machining feed means 30 includes a machining feed motor 31 and the like. The processing feed motor 31 is for processing and feeding the moving base 21 on which the grinding means 20 is mounted along the guide rail 33. The processing feed motor 31 is attached to the column portion 3 erected from the apparatus main body 2 of the grinding apparatus 1, and a lead screw 34 is attached to the output shaft. The lead screw 34 is disposed in parallel with the Z-axis and is supported by the column portion 3 so as to be rotatable around the axis. The lead screw 34 is screwed into a nut (not shown) attached to the moving base 21. The guide rail 33 is attached to the column portion 3 in parallel with the Z axis, and supports the movable base 21 so as to be slidable in the Z axis direction.

  The grinding means 20 performs grinding while supplying a grinding liquid as a back surface WR (corresponding to the upper surface) machining liquid of the plurality of workpieces W held by the holding means 10. As shown in FIG. 1, the grinding means 20 includes a spindle 24 on which a grinding wheel 23 is mounted at the tip, a spindle motor 27, and the like.

  The grinding wheel 23 includes a disk-shaped grinding wheel base 25 and a plurality of grinding wheels 26. The grindstone base 25 is attached to a flange portion 24a provided at the tip of the spindle 24 with a bolt or the like. The grinding wheel 26 is provided on the outer edge of the grinding wheel base 25 on a ring. The grinding wheel 26 is composed of well-known abrasive grains and a bonding agent that hardens the abrasive grains. The spindle 24 is rotated about the Z axis parallel to the vertical direction by a spindle motor 27, whereby the back surface of the workpiece W is obtained. Grind the WR. As shown in FIG. 4, the grinding wheel 26 passes on the rotation axis A of the processing position holding means 10 by the rotation of the spindle motor 27. For this reason, during grinding, a part of the back surface WR of the workpiece W held by the holding means 10 is exposed.

  The spindle 24 is accommodated in the spindle housing 28 so as to be rotatable about the Z axis. The spindle housing 28 is held by a support portion 29 attached to the moving base 21. The spindle motor 27 rotates the spindle 24, that is, the grinding wheel 23 around the Z axis.

  The height measuring device 40 is for measuring the height of the back surface WR from the holding surface 10 a of the holding means 10 of the plurality of workpieces W ground by the grinding means 20. As shown in FIG. 2, the height measuring device 40 includes a main body portion 41, a measurement arm 42 supported by the main body portion 41 so as to be swingable in the vertical direction, and 2 attached to a distal end portion 42 a of the measurement arm 42. One measuring needle 43 is provided. The main body 41 is disposed in the vicinity of the processing position holding means 10. The main body 41 supports the measuring arm 42 so as to be swingable so that the tip 42a moves up and down. When pressurized gas is supplied from the air supply source 44 to the main body 41, the base end side is pressed downward from the swing center M of the measurement arm 42 to raise the distal end portion 42 a of the measurement arm 42. An air cylinder 45 is provided. The main body 41 is provided with detection means (not shown) for detecting the rotational position of the measuring arm 42 around the swing center M and detecting the height of the back surface WR of the workpiece W. . The detection unit outputs the detection result to the control unit 100.

  The measuring arm 42 is formed in a cylindrical bar shape, and is supported by the main body 41 so as to be swingable about the base end portion 42b. A needle support member 46 to which two measurement needles 43 are attached is provided at the distal end portion 42 a of the measurement arm 42.

  The two measuring needles 43 are formed in a cylindrical bar shape and are attached to the needle support member 46. The two measuring needles 43 include a parallel portion 47 parallel to the measuring arm 42, a contact portion 48 that extends from the tip of the parallel portion 47 toward the holding surface 10a of the holding means 10 and contacts the back surface WR of the workpiece W. It has. The lower end of the contact portion 48 forms a contact point 48a that comes into contact with the back surface WR of the workpiece W. In the two measuring needles 43, contact points 48a to be brought into contact with the back surface WR of the workpiece W exposed during grinding are arranged at the same height position. As shown in FIG. 5, the two measuring needles 43 are formed such that the parallel portions 47 are parallel to each other and spaced apart in the horizontal direction, and the lengths L of the contact portions 48 are equal. As shown in FIGS. 3 and 4, the two measuring needles 43 are parallel and adjacent to each other along a circumference C (indicated by a one-dot chain line in FIG. 4) around the rotation axis A of the holding means 10. The workpieces W are disposed with a spacing W1 that is larger than the circumferential spacing W2 between the workpieces W.

  In the present invention, the circumferential interval W2 between adjacent workpieces W refers to the interval W2 on the circumference C where the contact point 48a passes on the back surface WR of the workpiece W. In the present embodiment, the interval W1 between the two measuring needles 43 refers to the interval W1 between the centers of the measuring needles 43. The interval W1 between the two measuring needles 43 is formed sufficiently smaller than the interval W3 between the points P where the outer edge of the back surface WR of the workpiece W intersects the circumference C.

  In this way, by arranging the two measuring needles 43, during grinding for holding a plurality of workpieces W on the holding means 10 via the holding member M, as shown by dotted lines in FIG. When one measuring needle 43 is positioned between the plurality of workpieces W, the other measuring needle 43 contacts one of the back surfaces WR of the plurality of workpieces W, and the workpiece W The height position of the back surface WR is constantly measured.

  The control means 100 controls the above-described components constituting the grinding apparatus 1 to cause the grinding apparatus 1 to perform a machining operation on the workpiece W. The control means 100 is mainly composed of an arithmetic processing unit constituted by a CPU or the like, a microprocessor (not shown) provided with a ROM, a RAM, etc., and a display means (not shown) for displaying the state of the machining operation, an operator Are connected to an operating means (not shown) used when registering processing content information and the like.

  Next, the processing operation of the grinding apparatus 1 according to this embodiment will be described. First, the operator registers the machining content information in the control means 100, and when the operator gives an instruction to start the machining operation, the grinding device 1 starts the machining operation. In the processing operation, when a plurality of workpieces W adhered to the holding member M on the surface WS are placed on the holding means 10 at the attachment / detachment position separated from the lower side of the grinding means 20, the control means 100 causes the workpiece 100 to move. The workpiece W is sucked and held by the holding means 10. Further, the control means 100 supplies the pressurized gas from the air supply source 44 to the air cylinder 45, and the tip end portion 42a of the measurement arm 42 and the measurement needle 43 are indicated by a two-dot chain line in FIG. It raises rather than the holding surface 10a of the holding means 10. FIG.

  The control means 100 moves the holding means 10 by the holding means moving means, positions the holding means 10 at the processing position, stops the supply of pressurized gas from the air supply source 44 to the air cylinder 45, and 2 The contact points 48a of the two measuring needles 43 are brought into contact with the back surface WR of the workpiece W held by the holding means 10. The control means 100 positions the grinding wheel 23 rotated by the spindle motor 27 on the rotation axis A of the rotating holding means 10 as shown in FIG. Then, the control unit 100 gradually lowers the grinding wheel 23 by the processing feeding unit 30 and feeds the grinding wheel 23 to the back surface WR of the workpiece W. The back surface WR of the workpiece W is ground with the grinding wheel 26 of the grinding wheel 23. During grinding, the height measuring device 40 always measures the height of the back surface WR.

  When the height of the back surface WR of the workpiece W reaches a desired height based on the detection result of the height measuring device 40, the control means 100 separates the grinding means 20 from the workpiece W by the work feeding means 30. Let Further, the control unit 100 supplies the pressurized gas from the air supply source 44 to the air cylinder 45, and raises the distal end portion 42 a of the measurement arm 42 and the measurement needle 43 from the holding surface 10 a of the holding unit 10.

  Thereafter, the control means 100 moves the holding means 10 from the processing position below the grinding means 20 toward the attachment / detachment position by the holding means moving means. When the holding unit 10 is located at the attachment / detachment position, the control unit 100 stops the movement of the holding unit 10 by the holding unit moving unit and releases the suction and holding of the workpiece W by the holding unit 10. When the workpiece W after grinding and the workpiece W before grinding are exchanged, the grinding apparatus 1 performs grinding on the workpiece W in the same manner as the above-described steps.

  As described above, the grinding apparatus 1 according to the present embodiment includes two measuring needles 43, and the two measuring needles 43 are juxtaposed along the circumference around the rotation axis A of the holding unit 10 and adjacent to each other. The workpieces W are spaced apart from each other by a gap W1 that is larger than the circumferential gap W2. Further, the interval W1 between the two measuring needles 43 is formed sufficiently smaller than the interval W3 between the points P where the outer edge of the back surface WR of the workpiece W intersects the circumference C. For this reason, when one measuring needle 43 is positioned between the plurality of workpieces W during grinding, the other measuring needle 43 always comes into contact with the back surface WR of the plurality of workpieces W and can be measured. Therefore, even when holding and grinding a plurality of workpieces W at the same time, the measuring needle 43 does not fall or get caught between the workpieces W, so that the measuring needle 43 can be stabilized. The thickness of the workpiece W can be measured by contacting the back surface WR of the workpiece W.

  In the present invention, the grinding apparatus 1 may include a plurality of holding means 10 and grinding means 20. In the present invention, the height position of the holding surface 10a of the holding means 10 is measured with the height measuring device 40 in advance of grinding, and the control means 100 calculates the difference from the height position measured during grinding. Then, the thickness of the workpiece W may be obtained from the difference value, and control may be performed so that the workpiece W is ground until a desired thickness is obtained.

  Furthermore, in the present invention, when the outer diameter of the holding surface 10a of the holding means 10 is formed substantially equal to the outer diameter of the workpiece W or the holding member M, the outer peripheral portion 10b (see FIG. (2) A height measuring device (not shown) having one measuring needle in contact with it is provided separately. The control means 100 contacts the outer peripheral portion 10b with a measuring needle of a height measuring device separately provided during grinding, constantly measures the height position of the holding means 10, and uses the measured value or the like to determine the workpiece W. You may make it require | calculate the thickness of.

  The present invention is not limited to the above embodiment. That is, various modifications can be made without departing from the scope of the present invention.

DESCRIPTION OF SYMBOLS 1 Grinding device 10 Holding means 10a Holding surface 20 Grinding means 40 Height measuring instrument 43 Measuring needle 48a Contact point A Rotating shaft C Circumference W Workpiece WR Back surface (upper surface)
W1 interval W2 interval

Claims (1)

A holding means having a holding surface for holding the workpiece; a grinding means for grinding an upper surface of the workpiece held by the holding means; and a height of the upper surface of the workpiece ground by the grinding means. A grinding device comprising a height measuring device for measuring,
The holding means has a holding surface that holds a plurality of workpieces and has a size larger than the size of the workpiece, and is centered on a rotation axis that is orthogonal to the holding surface and passes through the center of the holding surface. The plurality of workpieces are held in a circumferential direction on a circumference around the rotation axis on the holding surface,
The height measuring instrument includes two measuring needles arranged at the same height with contact points to be brought into contact with the upper surface of the workpiece, and the two measuring needles are centered on the rotation axis of the holding means. Arranged along the circumference and spaced apart by a distance greater than the circumferential distance between adjacent workpieces,
When grinding a plurality of workpieces, when one of the measuring needles is positioned between the plurality of workpieces, the other measuring needle contacts one of the upper surfaces of the plurality of workpieces. And constantly measuring the height position of the workpiece.

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