JP2014042959A - 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 rough grinding wheel (a first wheel) 36 and a finishing grinding wheel (a second wheel) 37 having a larger diameter than the rough grinding wheel 36. A diameter D1 of the rough grinding wheel 36 has a length substantially the same as a radius r of a processed object 1, and a difference between a radius R2 of the finishing grinding wheel 37 and a radius R1 of the rough grinding wheel 36 is equal to or larger than the radius r of the processed object 1. When directing the rotated double wheel 35 toward the processed object 1 and descending the double wheel 35 to grind a processed surface 1a, outer peripheries of the grinding wheels 36 and 37 are positioned at a center of the processed object 1 to carry out grinding of the whole processed surface 1a, in each of the processes of rough grinding with the rough grinding wheel 36 and finishing grinding with the finishing grinding wheel 37.

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 device of the present invention is a grinding device comprising a holding table having a holding surface for rotatably holding a workpiece, and a grinding means for grinding the workpiece held by the holding table, The grinding means includes a first wheel having a diameter approximately the same as the radius of the workpiece, and a second wheel having a larger diameter than the first wheel disposed concentrically on the outer peripheral side of the first wheel. A double wheel in which the difference between the radius of the second wheel and the radius of the first wheel is greater than or equal to the radius of the workpiece, and a spindle on which the double wheel is mounted, Vertical movement means for moving the grinding means in the vertical direction relative to the holding surface of the holding table; and workpieces held on the holding table on the outer circumference of the first wheel and the outer circumference of the second wheel, respectively. So that the center of And positioning means for positioning the holding table, characterized in that it comprises a.

  According to the present invention, when the center of the workpiece held on the holding table is positioned on the outer periphery of the first wheel by the positioning means, and when the center of the workpiece is positioned on the outer periphery of the second wheel, respectively. In this state, the workpiece is rotated together with the holding table, the grinding means is brought close to the workpiece by the vertical movement means, the rotating first wheel and the second wheel are pressed against the workpiece, the first wheel and the second wheel Grind with wheels sequentially. Here, the first wheel and the second wheel can be applied as a rough grinding wheel and a finish grinding wheel, for example.

  According to the present invention, since the first wheel and the second wheel of the double wheel are arranged concentrically, the footprint is smaller than when these grinding wheels are arranged in parallel. The first wheel has a diameter that is substantially the same as the workpiece radius, and the difference between the radius of the second wheel and the radius of the first wheel is greater than or equal to the workpiece radius. In each grinding process using the wheel and the second wheel, the outer periphery of the grinding wheel is positioned at the center of the work piece and grinding is performed, so that in each process of rough grinding and finish grinding, the grinding wheel is not interfered with the other side. The entire surface of the workpiece can be reliably ground. Further, there is an advantage that the outer diameter of the double wheel, that is, the outer diameter of the second wheel can be made as small as possible.

  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 side sectional drawing which shows the double wheel of other embodiment of this invention, Comprising: In this double wheel, (a) The state which is performing rough grinding with a rough grinding wheel, (b) Finish grinding by a finish grinding wheel It shows the state of doing.

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 a substantially middle portion in the longitudinal direction. A vacuum chuck type is provided in the recess 13 via a moving base (positioning means) 14. The disc-shaped holding table 20 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 in a planar shape 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.

  Strictly speaking, the holding surface 21 of the holding table 20 is formed in a conical surface shape having an inclined surface with a small inclination angle (for example, about 0.01 °) with the rotation center as a vertex, and the workpiece 1 When adsorbed on the holding surface 21, it is slightly deformed into a conical shape following the holding surface 21. When grinding the workpiece 1, the holding table 20 is set to be slightly inclined so that a grinding surface and an inclined surface of a grinding wheel described later are parallel to each other.

  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, and as shown in FIG. 2, an annular coarse grinding wheel (first wheel) 36 and an annular finish grinding having a larger diameter than the coarse grinding wheel 36. A wheel (second wheel) 37 is concentrically arranged.

  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 moving table 14 is moved to send the workpiece 1 to the grinding region 11A, the workpiece 1 is positioned at a predetermined position, and the double wheel 35 is rotated by the vertical moving means 40. By lowering 35 until a predetermined grinding height is reached, the work surface of the work piece 1 is ground.

  The grinding is first performed with the rough grinding wheel 36 on the inner peripheral side with respect to the work surface, and then the finish grinding with the finish grinding wheel 37 on the outer peripheral side is performed. 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 rough grinding wheel 36 on the inner peripheral side and the finish grinding wheel 37 on the outer peripheral side, 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 (rough grinding grindstone 361 and finish grinding grindstone 371) fixed in an annular shape 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 rough grinding wheel 36 and the finish grinding wheel 37 are formed on a horizontal plane perpendicular to the axial direction of the spindle 32. These grinding surfaces 362 and 372 are formed in the same plane.

  As shown in FIG. 3B, the diameter D1 of the rough grinding wheel 36 is substantially the same length as the radius r of the workpiece 1, and the radius R2 of the finish grinding wheel 37 and the radius R1 of the rough grinding wheel 36 are the same. The difference is set to be equal to or larger than the radius r 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, as shown in FIG. 3, the movable table 14 is moved so that the upper surface of the workpiece 1, that is, the center of the workpiece surface 1a is positioned below the outer periphery of the rough grinding wheel 36, and the holding table 20 is rotated. To rotate the workpiece 1. Then, the grinding means 30 is lowered, and the grinding surface 362 of the rotating rough grinding wheel 36 is pressed against the rotating workpiece surface 1a. Thereby, the grinding surface 362 of the rough grinding wheel 36 passes through the center of the rotating workpiece surface 1a, and the entire surface of the workpiece surface 1a is roughly ground by the grinding surface 362.

  As described above, the radius r of the workpiece 1 is substantially the same as the diameter D1 of the rough grinding wheel 36, and the difference between the radius R2 of the finish grinding wheel 37 and the radius R1 of the rough grinding wheel 36 is the workpiece. When the workpiece 1 is positioned so that the outer periphery of the rough grinding wheel 36 passes through the center of the workpiece surface 1a with respect to the dimension setting of a radius r of 1 or more, the grinding surfaces 362 and 372 are formed in the same plane. However, the entire surface of the workpiece 1 is rough ground without interfering with the finish grinding wheel 37 on the outer peripheral side.

  When the workpiece 1 reaches a predetermined thickness by rough grinding, the grinding means 30 is once raised to separate the rough grinding wheel 36 from the workpiece 1. Subsequently, the movable table 14 is moved while the holding table 20 is rotated. As shown in FIG. 4, the center of the work surface 1a is positioned below the outer periphery of the finish grinding wheel 37, and the grinding means 30 is lowered to rotate. The grinding surface 372 of the finish grinding wheel 37 is pressed against the rotating surface 1a. As a result, the grinding surface 372 of the finish grinding wheel 37 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.

  In the finish grinding, the difference between the radius R2 of the finish grinding wheel 37 and the radius R1 of the rough grinding wheel 36 is set to a dimension that is not less than the radius r of the workpiece 1, and the outer periphery of the finish grinding wheel 37 is the center of the work surface 1a. By positioning the workpiece 1 so as to pass through the workpiece 1, the workpiece 1 can be processed without interfering with the inner peripheral coarse grinding wheel 36 even if the grinding surfaces 362 and 372 are formed in the same plane. The entire surface 1a is finish ground.

  When the workpiece 1 reaches the target thickness by finish grinding, the grinding means 30 is raised to separate the finish grinding wheel 37 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 apparatus 10 described above, the rough grinding wheel 36 and the finish grinding wheel 37 are arranged concentrically to form the double wheel 35, and these grinding wheels are arranged in parallel. The footprint can be reduced as compared with the case where it is arranged.

  The diameter D1 of the rough grinding wheel 36 is substantially the same length as the radius r of the workpiece 1, and the difference between the radius R2 of the finish grinding wheel 37 and the radius R1 of the rough grinding wheel 36 is the radius of the workpiece 1. For the dimension setting of r or more, rough grinding and finishing are performed by positioning the outer periphery of each grinding wheel 36, 37 at the center of the work surface 1a in each grinding step by the rough grinding wheel 36 and the finish grinding wheel 37. In each grinding step, the entire surface 1a can be reliably ground without interfering with the other grinding wheel. Moreover, the effect that the outer diameter of the double wheel 35, ie, the outer diameter of the finish grinding wheel 37, can be made as small as possible can also be obtained.

(4) Other Embodiments In the above embodiment, the first wheel on the inner circumference side of the present invention is the rough grinding wheel 36, and the second wheel on the outer circumference side of the present invention is the finish grinding wheel 37. As shown in FIG. 5, that is, as shown in FIG. 5, the first grinding wheel 37 may be the finish grinding wheel 37 and the second grinding wheel 36 may be the rough grinding wheel 36.

  In this embodiment, in a state where the double wheel 35 is rotated, the workpiece 1 is first roughly ground with the coarse grinding wheel 36 on the outer peripheral side as shown in FIG. 5 (a), and then in FIG. 5 (b). As shown, the workpiece 1 is finish ground by the finish grinding wheel 37 on the inner peripheral side. In both the rough grinding and finish grinding processes, grinding is performed with the outer periphery of the rotated grinding wheels 36 and 37 passing through the center of the work surface 1a, so that the entire work surface 1a is ground in each process. To do.

DESCRIPTION OF SYMBOLS 1 ... Workpiece 10 ... Grinding device 14 ... Moving stand (positioning means)
DESCRIPTION OF SYMBOLS 20 ... Holding table 21 ... Holding surface 30 ... Grinding means 32 ... Spindle 35 ... Double wheel 36 ... Coarse grinding wheel (first wheel)
37 ... Finish grinding wheel (second wheel)
40. Vertical movement means

Claims (1)

A grinding apparatus comprising a holding table having a holding surface for rotatably holding a workpiece, and a grinding means for grinding the workpiece held by the holding table,
The grinding means includes
A first wheel having a diameter of approximately the same length as the radius of the workpiece;
A second wheel having a larger diameter than the first wheel disposed concentrically on the outer peripheral side of the first wheel, and the difference between the radius of the second wheel and the radius of the first wheel is processed A double wheel that is greater than the radius of the object,
A spindle on which the double wheel is mounted,
Vertical movement means for moving the grinding means in a vertical direction relative to the holding surface of the holding table;
Positioning means for positioning the holding table so that the centers of the workpieces held on the holding table are positioned on the outer periphery of the first wheel and the outer periphery of the second wheel, respectively.
A grinding apparatus comprising:

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