JP2014042950A - Grinding apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a grinding apparatus which allows a footprint to be downsized.SOLUTION: A double wheel 35 is constructed by concentrically arranging a finishing grinding wheel 36 and a rough grinding wheel 37 having a larger diameter than the finishing grinding wheel 36. A diameter D1 of the finishing grinding wheel 36 is equal to or larger than a diameter d of a processed object 1, whereas a diameter D2 of the rough grinding wheel 37 is equal to or larger than the double of the diameter d of the processed object 1, and a difference between a radius R1 of the finishing grinding wheel 36 and a radius R2 of the rough grinding wheel is equal to or larger than a radius r of the processed object 1. The double wheel 35 is rotated and the processed object 1 is horizontally moved below the rough grinding wheel 37 to carry out rough grinding, and subsequently an outer periphery of the finishing grinding wheel 36 is positioned at a center of the processed object 1 having passed the rough grinding wheel 37, in order to carry out finishing grinding of the auto-rotating processed object 1 with the finishing grinding wheel 36.

Description

  The present invention relates to a grinding apparatus for grinding a plate-like object such as a semiconductor wafer as a workpiece.

  In the manufacturing process of semiconductor devices, lattice-shaped division planned lines are set on the surface of a wafer made of a semiconductor material such as silicon or gallium arsenide, and ICs, LSIs, etc. are formed in a large number of rectangular regions surrounded by the planned division lines. A device having the electronic circuit is formed. This wafer is divided into a large number of chip-like devices by cutting along a predetermined division line after undergoing a predetermined process such as grinding the back surface and thinning it to a set thickness. The device thus obtained is packaged with resin or ceramic and mounted on various electronic devices.

  As a wafer grinding apparatus, the wafer is held on the holding table with the work surface exposed upward, and the grinding wheel provided on the grinding wheel is rotated on the wafer while rotating the grinding wheel disposed above the holding table. A type of grinding by pressing is common. When grinding wafers, rough grinding is performed first, followed by finish grinding to achieve efficient grinding. To achieve this, grinding wheels for rough grinding and finish grinding are arranged in parallel. A configuration is known in which wafers are sequentially transferred to these grinding wheels by a turntable rotating (for example, Patent Document 1).

JP 2000-288888 A

  By the way, in recent years, semiconductor wafers have been increased in size, and development of wafers having a diameter of 450 mm, for example, has been progressing. It is undeniable that various apparatuses for processing a wafer are increased in size with an increase in the size of the wafer, but it is desired to make the footprint as small as possible. The same applies to the above-described wafer grinding apparatus.

  This invention is made | formed in view of the said situation, The main subject is providing the grinding device which enables size reduction of a footprint.

  The grinding apparatus of the present invention is a grinding apparatus comprising a holding table that rotatably holds a workpiece, and a grinding means that grinds the workpiece held by the holding table. A finish grinding wheel that includes a grinding wheel and has a diameter equal to or greater than the diameter of the work piece, and a diameter that is at least twice the diameter of the work piece that includes a rough grinding wheel disposed concentrically on the outer peripheral side of the finish grinding wheel. A double grinding wheel having a difference between a radius of the rough grinding wheel and a radius of the finish grinding wheel equal to or greater than a radius of the workpiece; and the double wheel is mounted. A spindle for rotating the double wheel, and a vertical moving means for moving the grinding means in the vertical direction, and the holding for holding the workpiece under the rough grinding wheel positioned at a predetermined height. table Horizontal movement means for moving the holding table so that the outer periphery of the finish grinding wheel is positioned at the center of the work piece that has been moved in the horizontal direction to perform rough grinding on the work piece that has passed through the rough grinding wheel; It is characterized by providing.

  According to the present invention, the holding table is horizontally moved by the horizontal moving means, and the workpiece held on the holding table is passed through the rotating double wheel, so that the workpiece is roughly ground and the finish grinding wheel. Can be ground continuously. Since the double grinding wheel and the finishing grinding wheel are arranged concentrically, the footprint is smaller than when these grinding wheels are arranged in parallel. When the difference between the radius of the rough grinding wheel of the double wheel and the radius of the finish grinding wheel is equal to or larger than the radius of the workpiece, the entire surface of the workpiece can be ground in each step of rough grinding and finish grinding.

  In the present invention, the grinding surface of the finish grinding wheel includes a form that is formed vertically above the grinding surface of the rough grinding wheel. In this configuration, when the difference between the radius of the rough grinding wheel of the double wheel and the radius of the finish grinding wheel is equal to or greater than the workpiece radius and equal to or less than the workpiece diameter, each process of the rough grinding and the finish grinding is performed. This makes it possible to reliably grind the entire work surface.

  According to the present invention, it is possible to provide a grinding apparatus that can reduce the footprint.

1 is an overall perspective view of a grinding apparatus according to an embodiment of the present invention. It is the (a) side sectional view and the (b) bottom view showing the double wheel of the grinding device. It is the (a) sectional side view which shows the state which is performing rough grinding with a rough grinding wheel, (b) is a figure which shows a planar image. It is (a) sectional side view which shows the state which is performing finish grinding with a finish grinding wheel, (b) is a figure which shows a planar image. It is a sectional side view which shows the modification of a double wheel.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
(1) Basic configuration and operation of grinding apparatus First, a basic configuration and operation of a grinding apparatus according to an embodiment will be described.
FIG. 1 shows an entire grinding apparatus 10 according to an embodiment. The grinding apparatus 10 uses a disk-shaped semiconductor wafer such as a silicon wafer as a workpiece (reference numeral 1 in FIG. 3), and grinds and thins at least one surface of the workpiece 1 to a predetermined thickness. Used to do.

  In FIG. 1, reference numeral 11 denotes a device base, and a wall portion 12 is erected at one end portion in the longitudinal direction of the device base 11 (the end portion on the right back side in FIG. 1). In FIG. 1, the longitudinal direction, the width direction, and the vertical direction of the apparatus base 11 are set as a Y direction, an X direction, and a Z direction, respectively.

  On the apparatus base 11, a recess 13 is formed on the side of the wall 12 from an approximately middle portion in the longitudinal direction. A vacuum chuck is provided in the recess 13 via a moving base (horizontal moving means) 14. A disc-shaped holding table 20 of the type is provided so as to be movable in the Y direction. The moving table 14 reciprocates along the Y direction by a moving mechanism (not shown) disposed in the apparatus table 11.

  The moving path of the moving table 14 is covered with bellows-like covers 15 and 16 provided on both sides of the moving table 14 in the moving direction. The covers 15 and 16 expand and contract as the moving table 14 moves, and the covers 15 and 16 prevent the grinding scraps from falling on the moving path.

  The holding table 20 is rotatably supported by the movable table 14 and is driven to rotate in one or both directions by a rotation driving mechanism (not shown), and the rotation stopped state is held. The upper surface of the holding table 20 is formed on a circular holding surface 21 on which the workpiece 1 is placed. The holding surface 21 is formed horizontally by a porous body. The diameter of the holding surface 21 is equivalent to the diameter of the workpiece 1.

  The holding surface 21 is brought into a negative pressure state by the operation of a suction mechanism (not shown), and the workpiece 1 placed on the holding surface 21 is sucked and held by the holding surface 21 by the negative pressure action. The workpiece 1 held on the holding table 20 in this way is positioned in the grinding region 11A when the movable table 14 moves to the wall 12 side. A grinding means 30 is disposed above the grinding region 11A.

  The grinding means 30 is provided on the front surface of the wall portion 12 of the apparatus base 11 so as to be movable up and down in the Z direction by the vertical movement means 40. The vertical movement means 40 is screwed into the lift slider 42 and a pair of left and right guide rails 41 fixed to the front surface of the wall portion 12 and extending in the Z direction, supported by the guide rail 41 so as to be slidable. The ball screw 43 and the motor 44 that rotate the ball screw 43 forward and backward are configured to raise and lower the elevating slider 42 along the guide rail 41 by the rotation of the ball screw 43.

  The grinding means 30 includes a cylindrical housing 31 whose axial direction extends in the Z direction, a spindle 32 coaxially and rotatably supported in the housing 31 (shown in FIG. 2A), and the spindle 32. The servomotor 33 to be driven and the double wheel 35 which is coaxially fixed to the lower end of the spindle 32 via a disk-shaped mount 34 and faces the workpiece 1 positioned in the grinding region 11A. .

  The double wheel 35 is a grinding wheel for grinding the workpiece 1. As shown in FIG. 2, the double wheel 35 includes an annular finish grinding wheel 36 and an annular coarse grinding wheel 37 having a larger diameter than the finish grinding wheel 36. They are arranged concentrically.

  In the grinding means 30, the housing 31 is fixed to the elevating slider 42 of the vertical moving means 40 via the holder 39, and moves up and down integrally with the elevating slider 42. As a result, the double wheel 35 is moved close to and away from the workpiece 1 held on the holding table 20. When the spindle 32 is rotationally driven by the servo motor 33, the double wheel 35 rotates.

  The moving end at which the moving table 14 moves away from the grinding region 11A in the direction away from the wall 12 is a carry-in / out region 11B. The workpiece 1 held on the holding table 20 is reciprocated between the grinding area 11A and the carry-in / out area 11B by the movement of the moving table 14.

  The front side of the recess 13 of the apparatus base 11 is a supply / recovery area 17 for the workpiece 1. In the center of the supply / recovery area 17, a two-bar link type pickup robot 50 is installed. Around the pickup robot 50, the cassette 51 and positioning means are counterclockwise as viewed from above. 52, carry-in means 53, carry-out means 54, spinner-type cleaning means 55, and cassette 56 are arranged.

  The cassette 51, the positioning means 52 and the carry-in means 53 are a system for carrying the workpiece 1 into the holding table 20, and the carry-out means 54, the cleaning means 55 and the cassette 56 hold the workpiece 1 after grinding on the holding table 20. It is a system to carry out from. The two cassettes 51 and 56 have the same structure, and are referred to as a carry-in cassette 51 and a carry-out cassette 56 according to applications. These cassettes 51 and 56 are configured to accommodate and transport a plurality of workpieces 1 in a stacked state, and are set at predetermined positions on the apparatus base 11. Both the carrying-in means 53 and the carrying-out means 54 have the same structure, and suction pads 53b and 54b for sucking the upper surface of the workpiece 1 by negative pressure action are attached to the tips of the horizontal swivel arms 53a and 54a, respectively. It is.

In the grinding apparatus 10 having the above configuration, the workpiece 1 is ground as follows.
First, one workpiece 1 is taken out from the carry-in cassette 51 by the pickup robot 50, and the workpiece 1 is placed on the positioning means 52 by the pickup robot 50 with the processing surface facing upward. The workpiece 1 is positioned at a predetermined transfer start position on the positioning means 52, and then the workpiece 1 is held by the suction pad 53b of the loading means 53, and is previously loaded and unloaded by swiveling the horizontal swivel arm 53a. It is mounted concentrically on the holding surface 21 of the holding table 20 positioned at 11B.

  The workpiece 1 is adsorbed and held on the holding surface 21 of the holding table 20 by negative pressure action, and the moving table 14 moves to the wall 12 side and is sent to the grinding region 11A. Then, the grinding means 30 that rotates the double wheel 35 is lowered by the vertical movement means 40 until the double wheel 35 reaches a predetermined grinding height, and the moving table 14 is moved in and out of the work piece 1 11B. The surface to be processed of the workpiece 1 is ground by appropriately combining the movement in the direction.

  The grinding is performed first on the surface to be processed by the rough grinding wheel 37 and then by the finish grinding wheel 36. At the time of grinding, a machining liquid is supplied to a surface to be processed from a machining liquid supply unit (not shown). Further, the thickness of the workpiece 1 is measured by a thickness measuring means (not shown). When the entire surface of the workpiece 1 is ground and the thickness reaches the target thickness, the grinding means 30 is raised to separate the double wheel 35 from the workpiece 1 and finish the grinding.

  After grinding, the holding table 20 is moved to the carry-in / out area 11B, and the workpiece 1 is not attracted to the holding surface 21, and the workpiece 1 is transferred into the cleaning means 55 by the carry-out means 54. The workpiece 1 is washed with water and dried in the cleaning means 55, and then transferred and accommodated in the carry-out cassette 56 by the pickup robot 50.

  The above is a cycle in which one workpiece 1 is ground, washed and collected, and this cycle is repeated. When all the workpieces 1 in the carry-in cassette 51 have been processed, the workpiece 1 is moved to the next step together with the carry-out cassette 56.

(2) Double wheel The above is the basic configuration and operation of the grinding apparatus 10, and the double wheel 35 will be described in detail.

(2-1) Configuration of Double Wheel As described above, the double wheel 35 is configured by concentrically arranging the inner peripheral side finish grinding wheel 36 and the outer peripheral side rough grinding wheel 37, As shown in FIG. 2, these grinding wheels 36 and 37 are provided on the lower surface of a disk-shaped frame 38. The frame 38 is fixed to the mount 34 so as to be concentric and detachable. The mount 34 is detachably fixed to a chuck 321 formed to protrude from the tip axis of the spindle 32, and each grinding wheel rotates together with the spindle 32.

  Each of the grinding wheels 36 and 37 is configured by a plurality of rectangular parallelepiped-shaped grindstones (finished grinding grindstone 361 and rough grinding grindstone 371) that are annularly fixed to the lower surface of the frame 38, respectively. As each of the grindstones 361 and 371, for example, a material obtained by mixing and molding diamond abrasive grains in a vitreous bond material is used. The grinding surfaces 362 and 372 formed on the lower surfaces of the finish grinding wheel 36 and the rough grinding wheel 37 are planes orthogonal to the axial direction of the spindle 32 and are formed in parallel with the holding surface 21 of the holding table 20. As shown in FIG. 2A, the grinding surface 362 of the finish grinding wheel 36 is formed above the grinding surface 372 of the rough grinding wheel 37 by a predetermined height in the vertical direction.

  As shown in FIG. 3B, the diameter D1 of the finish grinding wheel 36 has a diameter equal to or larger than the diameter d of the workpiece 1, and the diameter D2 of the rough grinding wheel 37 is the diameter of the workpiece 1. It has a diameter that is at least twice as large as d. The difference between the radius R1 of the finish grinding wheel 36 and the radius R2 of the rough grinding wheel 37 is set to be not less than the radius r of the workpiece 1 and not more than the diameter d of the workpiece 1.

(2-2) Grinding with a double wheel In the double wheel 35 having the above-described configuration, the workpiece 1 is ground as follows.
In the first rough grinding, before the workpiece 1 is sent to the grinding region 11A, the grinding means 30 and the vertical movement means 40 cause the grinding surface 372 of the rough grinding wheel 37 to roughly grind the workpiece surface 1a of the workpiece 1. Then, the double wheel 35 is rotated. And the holding table 20 is made into a rotation stop state, the moving stand 14 is moved to the wall part 12 side, and the workpiece 1 is sent to the grinding area | region 11A. As shown in FIG. 3, the workpiece surface 1 a is ground by the grinding surface 372 of the rotating rough grinding wheel 37 as the workpiece 1 is fed.

  By passing the lower side of the rough grinding wheel 37 from the outer peripheral side toward the inner peripheral side, the entire processing surface 1a of the workpiece 1 is ground. Since the grinding surface 362 of the finish grinding wheel 36 is above the grinding surface 372 of the rough grinding wheel 37, the workpiece 1 does not interfere with the finish grinding wheel 36, and the entire surface 1a is roughly ground.

  When the workpiece 1 reaches a predetermined thickness by rough grinding, the center of the workpiece surface 1a is positioned below the outer periphery of the finish grinding wheel 36, as shown in FIG. Rotate. Then, the grinding means 30 is lowered and the grinding surface 362 of the rotating finish grinding wheel 36 is pressed against the rotating workpiece surface 1a. As a result, the grinding surface 362 of the finish grinding wheel 36 passes through the center of the rotating workpiece surface 1a, and the entire surface of the workpiece surface 1a is finish-ground by the grinding surface 362.

  When the workpiece 1 reaches the target thickness by finish grinding, the grinding means 30 is raised to separate the finish grinding wheel 36 from the workpiece 1 and finish grinding. Thereafter, as described above, the workpiece 1 is cleaned by the cleaning means 55 and stored in the carry-out cassette 56.

(3) Operational Effects of One Embodiment According to the grinding device 10 described above, the grinding wheel 36 and the rough grinding wheel 37 are arranged concentrically to form the double wheel 35, so that these grinding wheels are arranged in parallel. The footprint can be reduced as compared with the case where it is arranged.

  Further, since the grinding surface 362 of the finish grinding wheel 36 is formed vertically above the grinding surface 372 of the rough grinding wheel 37, the difference between the radii R1, R2 of the grinding wheels 36, 37 as in this embodiment. Is set to be not less than the radius r of the work piece 1 and not more than the diameter d of the work piece 1, the work surface without interfering with the grinding wheel on the other side in each step of rough grinding and finish grinding. The entire surface of 1a can be reliably ground.

(4) Modification of One Embodiment As shown in FIG. 5, when the difference between the radius R1 of the finish grinding wheel 36 and the radius R2 of the rough grinding wheel 37 is set to be equal to or larger than the diameter d of the workpiece 1 The workpiece 1 can enter between the outer peripheral edge of the finish grinding wheel 36 and the inner peripheral edge of the rough grinding wheel 37. Thereby, when the workpiece 1 is processed and fed from the outer peripheral side of the rough grinding wheel 37 for rough grinding, the workpiece 1 does not interfere with the finish grinding wheel 36. For this reason, the grinding surfaces 362 and 372 of both grinding wheels 36 and 37 can be formed in the same plane.

  Even in this case, the rough grinding is performed by feeding the workpiece 1 to the rough grinding wheel 37 by the movement of the movable table 14 with the rotation of the workpiece 1 stopped. In the finish grinding, the center of the work surface 1a is positioned below the outer periphery of the finish grinding wheel 36, the holding table 20 is rotated to rotate the work 1 and the grinding means 30 is lowered so that the finish grinding wheel 36 is covered. In a state of passing through the center of the processing surface 1a, the entire surface of the processing surface 1a is finish-ground by the finish grinding wheel 36.

DESCRIPTION OF SYMBOLS 1 ... Workpiece 10 ... Grinding device 14 ... Moving stand (horizontal moving means)
DESCRIPTION OF SYMBOLS 20 ... Holding table 30 ... Grinding means 32 ... Spindle 35 ... Double wheel 36 ... Finish grinding wheel 361 ... Finish grinding wheel 362 ... Grinding surface of finish grinding wheel 37 ... Coarse grinding wheel 371 ... Coarse grinding wheel 372 ... Coarse grinding wheel Grinding surface 40 ... Vertical movement means

Claims (2)

A grinding apparatus comprising a holding table for rotatably holding a workpiece and a grinding means for grinding the workpiece held by the holding table,
The grinding means includes a finish grinding wheel including a finish grinding wheel having a diameter equal to or greater than the diameter of the workpiece, and a diameter of the work piece including a rough grinding wheel concentrically disposed on the outer peripheral side of the finish grinding wheel. A double grinding wheel having a diameter greater than or equal to twice the diameter of the rough grinding wheel, the difference between the radius of the rough grinding wheel and the radius of the finish grinding wheel being greater than or equal to the radius of the workpiece, A spindle mounted with a heavy wheel to rotate the double wheel,
Vertical movement means for moving the grinding means in the vertical direction;
The workpiece which has passed the rough grinding wheel while moving the holding table holding the workpiece under the rough grinding wheel positioned at a predetermined height in the horizontal direction to perform rough grinding on the workpiece. Horizontal moving means for moving the holding table so that the outer periphery of the finish grinding wheel is positioned at the center of
A grinding apparatus comprising:   The grinding apparatus according to claim 1, wherein the grinding surface of the finish grinding wheel is formed vertically above the grinding surface of the rough grinding wheel.

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