TWI651162B - Grinding device - Google Patents

Abstract

An object of the present invention is to provide a method capable of measuring the thickness of a workpiece by stabilizing a measuring needle so that it can contact the upper surface of the workpiece even when grinding is performed while holding a plurality of workpieces at the same time. Grinding device. The solution is a grinding device including a holding mechanism having a holding surface for holding a workpiece, a grinding mechanism for grinding the back surface of the workpiece held by the holding mechanism, and a measurement for grinding by the grinding mechanism. Height measuring device for the height of the back of the workpiece. The height measuring instrument is provided with two measuring pins arranged so that the contact point which contacts the back surface of a to-be-processed object is the same height position. The two measuring needles are arranged at intervals larger than the circumferential distance between adjacent workpieces arranged along the circumference centered on the rotation axis of the holding mechanism.

Description

Grinding device Field of invention

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

Background of the invention

In the case where various workpieces are thinned and ground to a desired thickness, grinding is performed while measuring the thickness of the workpiece, and grinding is terminated when the desired thickness is reached. As a method for measuring the thickness of a workpiece, there is known a method in which a contactor of a thickness measuring device is brought into contact with a surface of the workpiece and a surface of a holding table holding the workpiece to obtain a height difference from the difference. A contact-type measurement method for determining the thickness of a workpiece (see, for example, Patent Document 1).

On the other hand, among wafers formed of sapphire, gallium nitride (GaN), or the like as workpieces, there are wafers having a smaller diameter than ordinary wafers. Regarding the grinding of such small-diameter wafers, there has been a method of holding a plurality of wafers on the same holding surface of one holding table, and then grinding the plurality of wafers at the same time to reduce the cost of grinding. The technology of this time has been proposed (see, for example, Patent Document 2).

Prior art literature Patent literature

Patent Document 1: Japanese Patent Laid-Open No. 2000-006018

Patent Document 2: Japanese Patent Laid-Open No. 2012-101293

Summary of invention

In the case of grinding a plurality of wafers at the same time, if the contactor of the thickness measuring device is contacted with the surface of the object to be ground as described above, the contactor may be processed with a small diameter that is stuck in rotation. The problem that the height of the processed object from the holding surface cannot be measured stably between objects.

An object of the present invention is to provide a method capable of measuring the thickness of a workpiece by stabilizing a contact pin so that it contacts the upper surface of the workpiece, even when grinding is performed while holding a plurality of workpieces at the same time. Grinding device.

In order to solve the above problems and achieve the object, the grinding device of the present invention described in claim 1 includes a holding mechanism having a holding surface for holding a workpiece, and an upper surface for grinding the workpiece held by the holding mechanism. And a height measuring device for measuring the height of the upper surface of the workpiece to be ground by the grinding mechanism. The grinding device is characterized in that the holding mechanism has a holding surface that can hold a plurality of workpieces and is formed to have a size larger than the size of the workpieces, and can pass the holding surface perpendicular to and through the holding surface. The center rotation axis rotates as a center, and on the holding surface, the plurality are added on a circumference centered on the rotation axis. The workpiece is held in the circumferential direction, and the height measuring device is provided with two measuring pins for arranging the contact points in contact with the upper surface of the workpiece at the same height position. The rotation mechanism of the holding mechanism is arranged on the circumference and adjacent workpieces are arranged at a large interval in the circumferential direction. When grinding a plurality of workpieces, when one of the workpieces is measured, When the needle is located between the plurality of workpieces, the measuring needle on the other side will contact the upper surface of any one of the plurality of workpieces to measure the height position of the workpieces at all times. In addition, in the claim 1, the circumferential distance between the adjacent workpieces in the circumferential direction means that the workpieces are arranged at equal intervals in the circumferential direction, which means that the adjacent workpieces are adjacent to each other. In the case where the objects to be processed are not arranged at equal intervals in the circumferential direction, the interval between the objects to be processed that is the most spaced apart among the intervals between adjacent objects to be processed.

The grinding device according to the present invention has two measuring pins, and the two measuring pins are arranged at a distance longer than the circumferential direction of adjacent workpieces arranged along a circle centered on the rotation axis of the holding mechanism. Large intervals are arranged separately. Therefore, when the measuring pin on one side is located between a plurality of workpieces during grinding, the measuring pin on the other side must be in contact with the upper surface of the plurality of workpieces and become measurable. Therefore, even in the case where grinding is performed while holding a plurality of workpieces at the same time, there is no case where the measuring needles fall between the workpieces or are caught by the workpieces, and the measuring needles can be stabilized to The thickness of the workpiece can be measured by making it contact the upper surface of the workpiece.

1‧‧‧Grinding device

10‧‧‧ holding agency

10a‧‧‧ keep face

100‧‧‧ Control agency

2‧‧‧device body

20‧‧‧Grinding mechanism

21‧‧‧ Mobile Abutment

23‧‧‧Grinding Wheel

24‧‧‧ Spindle

24a‧‧‧ flange

25‧‧‧ Millstone Abutment

26‧‧‧Grinding grinding stone

27‧‧‧ Spindle motor

28‧‧‧ Spindle housing

29‧‧‧ support

3‧‧‧ pillar

30‧‧‧Processing feed mechanism

31‧‧‧Process feed motor

33‧‧‧Guide

34‧‧‧ Lead screw

40‧‧‧ Altimeter

41‧‧‧Body

42‧‧‧ measuring arm

42a‧‧‧Front end

42b‧‧‧base end

43‧‧‧ measuring needle

44‧‧‧Air supply source

45‧‧‧ cylinder

46‧‧‧ Needle support member

47‧‧‧ Parallel

48‧‧‧Contact

48a‧‧‧contact point

A‧‧‧rotation shaft

C‧‧‧circle

L‧‧‧ Length of contact

M‧‧‧ holding member

c‧‧‧swing center

P‧‧‧ Intersection

W‧‧‧Processed

W1, W2, W3‧‧‧ intervals

WR‧‧‧Back (top)

WS‧‧‧ surface

FIG. 1 is an external perspective view showing a configuration of a grinding device according to the embodiment.

FIG. 2 is a perspective view of a holding mechanism, a height measuring instrument, and the like of the grinding apparatus according to the embodiment.

FIG. 3 is a perspective view of a height measuring device and a plurality of workpieces of the grinding device according to the embodiment.

FIG. 4 is a plan view of a height measuring device and the like of the grinding device according to the embodiment, and a plurality of workpieces.

Fig. 5 is a side view of a height measuring device and a plurality of workpieces of the grinding device according to the embodiment.

Forms used to implement the invention

The aspect (embodiment) for implementing the present invention will be described in more detail with reference to the drawings. The present invention is not limited by the contents described in the following embodiments. In addition, the constituent elements described below include those which can be easily conceived by persons having ordinary knowledge in the technical field to which the present invention pertains or which are substantially the same. In addition, the structures described below can be appropriately combined. Moreover, various structures can be omitted, replaced, or changed without departing from the gist of the present invention.

A grinding apparatus according to an embodiment of the present invention will be described with reference to FIGS. 1 to 5. FIG. 1 is an external perspective view showing the structure of the grinding device according to the embodiment, FIG. 2 is a perspective view of a holding mechanism and a height measuring device of the grinding device according to the embodiment, and FIG. 3 is a height measuring device and the measuring device of the grinding device according to the embodiment. Plural A perspective view of the object to be processed. FIG. 4 is a plan view of the height measuring device of the grinding device according to the embodiment and a plurality of objects to be processed. Illustration.

The grinding device 1 according to the present embodiment is a device that performs grinding (corresponding to processing) on the workpiece W (shown in FIG. 3). Here, as the object W to be processed, in the present embodiment, a disc-shaped semiconductor wafer or an optical element wafer using silicon, sapphire, gallium nitride (GaN) or the like as a base material. The workpiece W is divided into a plurality of regions by, for example, predetermined division lines called streets formed in a grid shape on the surface WS, and elements are formed in these divided regions. The workpiece W, as shown in FIG. 3, adheres the surface WS to the holding member M, and maintains a plurality of states on the holding member M, and grinds the grinding stone 26 against the back surface WR of the back side of the surface WS. (Shown in Figs. 3 and 4) Grinding is performed. In the present embodiment, the holding member M is formed in a circular plate shape, and the five workpieces W are arranged at equal intervals in the circumferential direction at the outer edge portion of the holding member M.

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

The holding mechanism 10 is a mechanism that has a holding surface 10 a for holding and holding the plurality of processed objects W placed thereon by placing the surface WS of the processed object W with the holding member M interposed therebetween. As shown in FIG. 2, the holding mechanism 10 includes a disk-shaped portion formed of porous ceramics and the like, and is connected to a vacuum suction source (not shown) through a vacuum suction path (not shown). Placed on the holding surface 10a by way of suction through the holding member M The upper workpiece W is held.

That is, the holding mechanism 10 has a holding surface 10 a formed to have a size larger than that of the workpiece W. The holding mechanism 10 is a moving mechanism of a holding mechanism (not shown), and moves in the Y-axis direction in a range covering a machining position below the grinding mechanism 20 and a loading / unloading position separated from below the grinding mechanism 20. The holding mechanism 10 can attract and hold the processed object W by a rotation driving mechanism (not shown), which will be perpendicular to the holding surface 10a and pass through the rotation axis A of the center of the holding surface 10a. (Indicated) is rotated as the center. The holding mechanism 10 holds the plurality of workpieces W on the holding surface 10a via the holding member M, and holds the plurality of workpieces W on the circumference of the holding surface 10a on a circumference centered on the rotation axis A. Keep it at equal intervals in the direction.

The processing feed mechanism 30 moves the grinding mechanism 20 in parallel with the Z axis in a direction approaching and separating from the holding surface 10a. The processing feed mechanism 30 includes a processing feed motor 31 and the like. The processing feed motor 31 is a motor for feeding the moving base 21 provided with the grinding mechanism 20 along the guide rail 33. The processing feed motor 31 is mounted on the column portion 3 of the apparatus body 2 of the self-grinding device 1, and a lead screw 34 is mounted on the output shaft. The lead screw 34 is arranged parallel to 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 to a nut (not shown) mounted on the moving base 21. The guide rail 33 is mounted on the pillar 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 mechanism 20 supplies the machining liquid as a machining fluid to the back surfaces WR (corresponding to the upper surface) of the plurality of workpieces W held by the holding mechanism 10. Grinding mechanism for grinding liquid. As shown in FIG. 1, the grinding mechanism 20 includes a main shaft 24, a main shaft motor 27, and the like, and a grinding wheel 23 is mounted on the front end.

The grinding wheel 23 includes a disc-shaped grinding stone base 25 and a plurality of grinding stones 26. The grindstone abutment 25 is attached to a flange portion 24a provided at the front end of the main shaft 24 by a bolt or the like. The grinding stone 26 is provided on the outer edge of the stone base 25 so as to be on a ring. The grinding stone 26 is composed of a well-known abrasive grain and a binding agent capable of fixing the abrasive grain. The spindle motor 27 rotates the main shaft 24 around the Z axis parallel to the vertical direction, thereby grinding. The back surface WR of the workpiece W is shaved. Furthermore, as shown in FIG. 4, the grinding stone 26 can pass on the rotation axis A of the holding mechanism 10 at the processing position by the rotation of the spindle motor 27. Therefore, during grinding, a part of the back surface WR of the workpiece W held by the holding mechanism 10 is exposed.

The main shaft 24 is housed in the main shaft housing 28 so as to be rotatable around the Z axis. The spindle housing 28 is held on a support portion 29 mounted on the moving base 21. The spindle motor 27 can rotate the spindle 24 (ie, the grinding wheel 23) in a form around the Z axis.

The height measuring device 40 is a measuring device for measuring the height of the plurality of workpieces W ground by the grinding mechanism 20 from the holding surface 10 a to the back surface WR of the holding mechanism 10. 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 a vertical direction, and two measurement pins 43 attached to a tip portion 42 a of the measurement arm 42. The main body portion 41 is arranged near the holding mechanism 10 at the processing position. The main body portion 41 supports the measurement arm 42 so as to be swingable so that the front end portion 42a can move up and down. A cylinder 45 is provided on the body portion 41, and the cylinder 45 is supplied. When the pressurized gas from the air supply source 44 presses the base end side to a position lower than the swing center c of the measurement arm 42, the front end portion 42 a of the measurement arm 42 is raised. In addition, a detection mechanism (not shown) is provided on the main body portion 41 to detect the rotation position around the swing center c of the measurement arm 42 to detect the height of the back surface WR of the workpiece W. The detection mechanism outputs a detection result to the control mechanism 100.

The measurement arm 42 is formed in a cylindrical rod shape, and is supported by the main body portion 41 so as to be swingable around the base end portion 42 b as a center. A needle support member 46 to which two measurement needles 43 are mounted is provided on the front end portion 42 a of the measurement arm 42.

The two measurement needles 43 are formed in a cylindrical rod shape, and are attached to the needle support member 46. The two measurement needles 43 include a parallel portion 47 parallel to the measurement arm 42, and a contact portion 48 extending from the front end of the parallel portion 47 toward the holding surface 10 a of the holding mechanism 10 to contact the back surface WR of the workpiece W. The lower end of the contact portion 48 is formed with a contact point 48 a that is in contact with the back surface WR of the workpiece W. The two measuring needles 43 are arranged so that the contact points 48 a contacting the back surface WR of the workpiece W exposed during grinding are at the same height position. As shown in FIG. 5, the two measuring needles 43 are arranged so 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 made equal. As shown in FIGS. 3 and 4, two measuring needles 43 are arranged adjacent to each other along a circumference C (indicated by a chain line in FIG. 4) centered on the rotation axis A of the holding mechanism 10. The circumferential distance W2 between the workpieces W is also separated by a larger interval W1.

In addition, in the present invention, the circumferential distance W2 between adjacent workpieces W means that the contact point 48a passes through the back surface of the workpiece W. The interval W2 on the circle C on WR. In addition, in the present embodiment, the interval W1 between the two measuring needles 43 means the interval W1 between the centers of the measuring needles 43. The interval W1 between the two measuring needles 43 is formed to be much smaller than the interval W3 between the outer edge of the back surface WR of the workpiece W and the point P at which the circumference C intersects.

In this way, by arranging two measuring needles 43 to hold the plurality of workpieces W held by the holding mechanism 10 via the holding member M, as shown by a dotted line in FIG. When the measuring probe 43 is located between the plurality of workpieces W, the measuring probe 43 on the other side will contact the back surface WR of any one of the plurality of workpieces W to measure the back surface WR of the workpiece W at all times. Height position.

The control mechanism 100 is a mechanism that controls the above-mentioned constituent elements constituting the grinding device 1 to cause the grinding device 1 to perform a machining operation on the workpiece W. In addition, the control mechanism 100 is mainly composed of an arithmetic processing device composed of, for example, a CPU, and a microprocessor (not shown) including a ROM, a RAM, and the like. A mechanism, or an operating mechanism (not shown) used by an operator when registering processing content information is connected.

Next, the machining operation of the grinding device 1 according to this embodiment will be described. First, when the operator registers the processing content information in the control mechanism 100 and the operator gives an instruction to start the machining operation, the grinding device 1 starts the machining operation. In the machining operation, when the plurality of workpieces W with the surface WS adhered to the holding member M are placed on the holding mechanism 10 at the loading and unloading position separated from below the grinding mechanism 20, the control mechanism 100 will The workpiece W is sucked and held by the holding mechanism 10. In addition, the control mechanism 100 supplies the pressurized gas from the air supply source 44 to the cylinder 45 so that the front end portion 42a of the measurement arm 42 and the measurement needle 43 are compared with each other as shown by a two-dot chain line in FIG. 2. The holding surface 10a of the holding mechanism 10 is further raised.

The control mechanism 100 moves the holding mechanism 10 by the holding mechanism moving mechanism to position the holding mechanism 10 to the processing position, and stops the supply of the pressurized gas from the air supply source 44 to the air cylinder 45 to make two measurements The contact point 48 a of the needle 43 is in contact with the back surface WR of the workpiece W held by the holding mechanism 10. The control mechanism 100 positions the grinding wheel 23 rotated by the spindle motor 27 on the rotation axis A of the rotating holding mechanism 10 as shown in FIG. 4. Then, the control mechanism 100 gradually lowers the grinding wheel 23 by the processing feed mechanism 30 to grind the feed to the back surface WR of the workpiece W. The grinding wheel 26 of the grinding wheel 23 is used to grind the back surface WR of the workpiece W. During grinding, the height of the back surface WR can be measured at any time by the height measuring device 40.

When the height of the back surface WR of the workpiece W becomes a desired height based on the detection result of the height measuring device 40, the control mechanism 100 moves the grinding mechanism 20 away from the workpiece W by the processing feed mechanism 30. In addition, the control mechanism 100 supplies the pressurized gas from the air supply source 44 to the air cylinder 45 so that the front end portion 42 a of the measurement arm 42 and the measurement needle 43 rise more than the holding surface 10 a of the holding mechanism 10.

After that, the control mechanism 100 moves the holding mechanism 10 from the processing position below the grinding mechanism 20 to the loading / unloading position by the holding mechanism moving mechanism. Then, when the holding mechanism 10 is in the loading / unloading position, the control mechanism 100 stops to move the holding mechanism 10 by the holding mechanism moving mechanism, and releases The removal holding mechanism 10 holds and holds the workpiece W. When the workpiece W after grinding is exchanged with the workpiece W before grinding, the grinding apparatus 1 performs grinding on the workpiece W in the same manner as the above-mentioned steps.

As described above, the grinding device 1 of this embodiment is provided with two measuring needles 43 and the two measuring needles 43 are arranged along a circumference that is centered around the rotation axis A of the holding mechanism 10 and are adjacent to each other. The workpieces W are arranged at a distance W2 in the circumferential direction from each other with a larger interval W1. In addition, the interval W1 between the two measuring needles 43 is formed to be much smaller than the interval W3 between the outer edge of the back surface WR of the workpiece W and the point P at which the circumference C intersects. Therefore, when one of the measuring needles 43 is positioned between the plurality of workpieces W during grinding, the other measuring needle 43 will surely contact the back surface WR of the plurality of workpieces W and become measurable. Therefore, even in the case where grinding is performed while holding the plurality of workpieces W at the same time, there is no situation where the measuring needle 43 falls between the workpieces W or gets stuck by the workpieces W, and it is possible to The measurement needle 43 is set so as to be in contact with the back surface WR of the workpiece W, and the thickness of the workpiece W can be measured.

In the present invention, the grinding device 1 may include a plurality of holding mechanisms 10 and a grinding mechanism 20. In the present invention, the height position of the holding surface 10a of the holding mechanism 10 may be measured by the height measuring device 40 before grinding, so as to control the control mechanism 100 to calculate the height position measured during grinding. The difference is obtained by calculating the thickness of the workpiece W from the difference and grinding it to a desired thickness.

Furthermore, in the present invention, when the outer diameter of the holding surface 10a of the holding mechanism 10 is formed to be approximately the same as the outer diameter of the workpiece W or the holding member M At the same time, a height measuring device (not shown) having a measuring needle which is in contact with the outer peripheral portion 10b (shown in FIG. 2) of the outer periphery of the holding surface 10a is additionally provided. The control mechanism 100 may be configured such that a measuring needle of a height measuring device provided separately is brought into contact with the outer peripheral portion 10b during grinding, and the height position of the holding mechanism 10 is continuously measured to obtain the measured value from the measured values and the like. The thickness of the work W.

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

Claims (1)

A grinding device includes a holding mechanism having a holding surface for holding a workpiece, a grinding mechanism for grinding an upper surface of a workpiece held by the holding mechanism, and a method for measuring A height measuring device for the height of the upper surface of the workpiece, and the grinding device is characterized in that the holding mechanism has a holding surface that can hold a plurality of workpieces and is formed to have a size larger than the size of the workpiece, A rotation axis perpendicular to the holding surface and passing through the center of the holding surface may be used as a center to rotate, and the plurality of workpieces may be held in a circumferential direction on a circumference of the holding surface with the rotation axis as a center. In the above, the height measuring device is provided with two measuring pins arranged at the same height position as the contact points in contact with the upper surface of the workpiece, and the two measuring pins are set along the rotation axis of the holding mechanism as The center is arranged on the circumference, and the adjacent workpieces are arranged at a large interval in the circumferential direction. When grinding a plurality of workpieces, the measuring needle on one side is When in the plurality is between the workpiece, the other side of the measuring needle will be in contact with a plurality of any of the upper surface of the workpiece to be measured is often the height position of the workpiece.