JPH0512099B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Technical Field> The present invention relates to a surface grinding apparatus, and more particularly, to a surface grinding apparatus suitable for grinding the surface of a semiconductor wafer.

<Prior Art> As is well known to those skilled in the art, in the semiconductor device manufacturing process, it is necessary to grind the surface of a substantially disk-shaped semiconductor wafer to bring the thickness of the semiconductor wafer to a desired value. As a surface grinding device for grinding the surface of a semiconductor wafer, a surface grinding device of the type disclosed in Japanese Unexamined Patent Publication No. 152562/1988 is generally conveniently used. Such a surface grinding device includes a rotatably mounted support table, a plurality of semiconductor wafer holding chucks fixed to the support table, and a plurality of semiconductor wafer holding chucks that are rotatably mounted at intervals in the rotational direction of the support table. The grinding wheel includes a plurality of grinding wheels, a table rotation means for rotationally driving the support table, and a grindstone rotation means for rotating the grinding wheel.

In the surface grinding apparatus described above, a semiconductor wafer whose surface is to be ground is held on a chuck.
Each of the plurality of grinding wheels is rotated at a relatively high speed, and the support table is rotated at a relatively low speed. In this way, the semiconductor wafer held on the chuck fixed to the support table is sequentially passed through a plurality of rotating grinding wheels, and at this time, the semiconductor wafer is The surface of the wafer is ground.

Therefore, the above-mentioned surface grinding device is disclosed in the above-mentioned Japanese Patent Application Laid-Open No.
As can be seen from the description in Japanese Patent No. 152562, it has various advantages over other types of conventional surface grinding devices. However, it is still not completely satisfactory, and (a) a grinding wheel with a ring shape as a whole is used, but it is not possible to uniformly grind the entire surface of a semiconductor wafer with such a grinding wheel. The outer diameter of the grinding wheel must be sufficiently larger than the outer diameter of the semiconductor wafer to be ground. Therefore, as the diameter of the semiconductor wafer increases, the diameter of the grinding wheel must also increase accordingly. Although necessary, increasing the diameter of a grinding wheel, which is generally manufactured by bonding superabrasive grains such as natural or synthetic diamond abrasive grains by an appropriate method, is not always possible due to various points in the grinding wheel manufacturing process. (b) The only relative movement of the semiconductor wafer to the rotating grinding wheel during grinding is the feeding movement of the semiconductor wafer accompanying the relatively slow rotation of the support table; The grinding trajectory of a semiconductor wafer is a simple arc defined by the movement of the outer periphery of the rotating grinding wheel, and therefore the grinding resistance is relatively large, and the grinding trajectory is determined by the movement of the outer peripheral edge of the rotating grinding wheel. There are problems to be solved, such as the relatively large fluctuations in the grinding force, which makes it difficult to achieve sufficiently uniform grinding over the entire surface of the semiconductor wafer, limiting the grinding accuracy. .

<Prior Application Invention> In order to solve the above problem, the present inventor first supported a plurality of chucks in the specification and drawings of Patent Application No. 226720 of 1982 (title of invention: surface grinding device). An improved surface grinding device has been proposed which is rotatably mounted on a table and is provided with chuck rotation means for rotating a plurality of chucks. In such a surface grinding device, when the surface of the workpiece held on the chuck is ground by the grinding wheel, the grinding wheel is rotated and the chuck is rotated to grind the semiconductor wafer held on the chuck. can also be rotated, thus solving the above problems (a) and (b).

However, as a result of further studies on the surface grinding device proposed by the present inventors, it has been found that there remain problems with the chuck rotating means that should be further improved. That is, the chuck rotation means in the surface grinding device is composed of one common drive source and a plurality of drive connection means respectively disposed between the common drive source and each of the plurality of chucks. ing. Therefore, when the common drive source is energized, all of the plurality of chucks are rotationally driven, and when the common drive source is deenergized, the rotation of all of the plurality of chucks is stopped. However,
From the standpoint of improving grinding efficiency, the rotation of a particular chuck is stopped, the already ground semiconductor wafer is taken out, and the next semiconductor wafer to be ground is mounted on the chuck, and during this time In other chucks, it has been found desirable to be able to drive the chuck in rotation to accomplish the grinding of semiconductor wafers.

<Object of the Invention> The present invention has been made in view of the above facts, and its main purpose is to further improve the surface grinding device previously proposed by the present inventor to satisfy the above requirements. An object of the present invention is to provide an improved surface grinding device that enables the above-mentioned surface grinding.

<Summary of the Invention> As a result of extensive studies, the present inventor has incorporated into each of the plurality of drive coupling means a clutch means for controlling engagement and disengagement, preferably a clutch means constituted by a pneumatic clutch. It has been found that, by doing so, the above object can be achieved while minimizing the increase in manufacturing costs.

That is, according to the present invention, a support table rotatably mounted, a plurality of workpiece holding chucks rotatably mounted on the support table at intervals in the circumferential direction, and a workpiece held on the chucks. a grinding wheel rotatably mounted for grinding the surface of a processed workpiece; a table rotation means for rotationally driving the table; a chuck rotation means for rotationally driving the chuck; A grinding wheel rotating means for rotating the grinding wheel is provided, and the chuck rotating means includes one common drive source and a plurality of chucks each disposed between the common drive source and each of the chucks. There is provided a surface grinding apparatus characterized in that the drive coupling means each have a clutch means for controlling engagement and disengagement.

<Preferred Embodiments of the Invention> Hereinafter, preferred embodiments of the surface grinding apparatus constructed according to the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 schematically illustrates the main components of one embodiment of a surface grinding apparatus constructed in accordance with the present invention. The illustrated surface grinding device includes a support table 4 in the form of a relatively large diameter disk, which is rotatably mounted around a central axis 2 that extends substantially vertically (perpendicular to the plane of the paper in FIG. 1). Equipped with On this support table 4, a plurality of workpiece holding chucks 6 (four in the illustrated case) are rotatably mounted at intervals in the circumferential direction. The plurality of chucks 6 are
It is convenient that they are arranged at a plurality of positions, each having the same radial distance from the central axis 2 and equally spaced in the circumferential direction of the support table 4 (that is, spaced at equal angular intervals). It is.

Work areas A, B, C, and D are defined at a plurality of positions (four positions in the illustrated case) spaced apart in the circumferential direction of the support table 4, respectively. These working areas A, B, C, and D are spaced at equal intervals in the circumferential direction of the support table 4 (that is, spaced at equal angular intervals).
Advantageously, the mutual angular spacing in the working areas A, B, C and D corresponds to the mutual angular spacing in the plurality of chucks 6. The work area A is a workpiece removal and installation area, and in the workpiece removal and installation area A, the workpiece whose surface has been ground is picked up by a chuck 6 by an appropriate removal means (not shown). The new workpiece to be removed from the chuck 6 and whose surface is to be ground is placed on the chuck 6 by suitable mounting means (not shown). Working areas B, C, and D are a rough grinding area, an intermediate grinding area, and a finishing grinding area, respectively. Each of these grinding zones B, C and D is provided with a grinding wheel assembly having a grinding wheel 8, which in the rough grinding zone B is held on a chuck 6, as will be mentioned further below. The surface of the workpiece is roughly ground, the surface of the workpiece held on the chuck 6 is intermediately ground in the intermediate grinding zone C, and the surface of the workpiece held on the chuck 6 is ground in the final grinding zone D. The surface of the workpiece is finish ground.

Referring to FIG. 2 as well as FIG. 1, the configuration of the support table 4 and the chuck 6 mounted on the support table 4 will be described in detail.
A stationary main support shaft (not shown) is disposed that extends substantially vertically along the main support shaft, and a support table 4 is rotatably mounted on the upper end of the main support shaft. A table rotation means 10, which may be an electric motor, is drivingly connected to the support table 4 via a suitable transmission element (not shown), by means of which the support table 4 is rotated, as will be mentioned further below. It is rotated intermittently or continuously in the direction indicated by arrow 12 in FIG. Four chuck support blocks 14 are arranged at equal intervals in the circumferential direction on the periphery of the substantially horizontal upper surface of the support table 4.
(only one of which is shown in FIG. 2) is fixed, and the chuck 6 is rotatably mounted on each of the chuck support blocks 14. More specifically, the chuck support block 14, which may be generally cylindrical in shape, has an upwardly opening circular hole 16 in which bearing members 18 and 20 are disposed. The lower surface of the bearing member 18 abuts an annular shoulder formed in the hole 16, and an annular spacer member 22 is disposed between the bearing members 18 and 20, and provides a chuck support. The inner peripheral edge of the lower surface of the annular holding plate 23 fixed to the upper surface of the block 14 is brought into contact with the upper surface of the bearing member 20, and thus the bearing member 18
and 20 are held in place. The lower part of the rotating shaft 24 is inserted into the bearing members 18 and 20, and the rotating shaft 24 is thus rotatably mounted on the chuck support block 14.
The chuck 6 is fixed to the upper end of a rotating shaft 24 that projects upward beyond the chuck support block 14. The illustrated chuck 6 has a disk-shaped main portion 26, a circular protrusion 28 formed on the lower surface of the main portion 26, and a connecting screw portion 30 extending downward from the center of the circular protrusion 28. On the other hand, a circular recess 32 for receiving the circular protrusion 28 of the chuck 6 and a screw hole 33 bored in the center of the circular recess 32 are formed on the upper surface of the rotating shaft 24.
The connecting screw portion 30 of the chuck 6 is screwed into the screw hole 33 of the rotating shaft 24, and the chuck 6 is thus fixed to the upper end of the rotating shaft 24. When the chuck 6 is fixed to the rotating shaft 24 as required, there is a slight gap between the lower surface of the circular protrusion 28 of the chuck 6 and the bottom surface of the circular recess 32 of the rotating shaft 24, and there is a gap between the two. A closed space 34 is defined. A flow path 36 is formed in the rotating shaft 24 and extends in the axial direction from an upper end that opens at the bottom surface of the circular recess 32 to a lower end that opens at the lower surface of the rotating shaft 24. A hollow manifold 38 is fixed to the center of the bottom surface of the hole 16 formed in the chuck support block 14, and the lower end of the flow path 36 is communicated with the manifold 38. The manifold 38 is attached to the lower end of the chuck support block 14.
A flow path 40 is formed that extends radially from an inner end communicating with the chuck support block 14 to an outer end opening to the outer peripheral surface of the chuck support block 14. The outer end of the flow path 40 is connected via a line 44 with a suitable switching valve 42 to a vacuum source 46 and a source 48 of liquid, which may be water. On the other hand, the circular protrusion 28 and main portion 26 of the chuck 6 are formed with a plurality of holes (not shown) extending from the lower surface of the circular protrusion 28 to the upper surface of the main portion 26. When a workpiece such as a semiconductor wafer is placed on the upper surface of the chuck 6 in the workpiece removal and loading area A, the switching valve 42 is operated and the flow path 40 is connected to the vacuum source 46. Thus, the plurality of holes (not shown) formed in the chuck 6, the space 34, the flow path 36, the manifold 38, the flow path 40, and the conduit 44
Air is sucked through the chuck 6, and the workpiece is thus attracted and held on the chuck 6. When taking out the workpiece from the chuck 6 in the workpiece removal and mounting area A, the switching valve 42 is operated and the flow path 4
0 is connected to source 48. In this way, liquid such as water flows onto the upper surface of the chuck 6 through the pipe 44, the flow path 40, the manifold 38, the flow path 36, the space 34, and the plurality of holes (not shown) formed in the chuck 6. is supplied, thus chuck 6
The workpiece that had been attracted to the surface is floated up.

The chuck rotating means will be explained with reference to FIG. 2. In the illustrated example, a central support block 50 is fixed to the center of the substantially horizontal upper surface of the support table 4. A rotating shaft 52 is rotatably mounted. More specifically, the central support block 50 has a disc-shaped base 54 and a support column 56 extending substantially vertically upward from the center of the upper surface of the base 54. On the other hand, a large diameter portion 58 is provided at the bottom of the central rotating shaft 52.
A circular recess 60 opening downward is formed in the large diameter portion 58 . and,
The large diameter portion 58 of the central rotating shaft 52 is the bearing member 6
2 and 64, said central support block 50
It is rotatably attached to the supporting columnar part 56 of.
The lower surface of the bearing member 62 is connected to the central support block 5.
The bearing member 6
2 and the bearing member 64, and the upper surface of the bearing member 64 abuts the bottom surface (upper surface) of the circular recess 60, thus holding the bearing members 62 and 64 in position. There is. The upper end of the central rotation shaft 52 is drivingly connected to a common rotary drive source 68, which may be an electric motor, via a suitable transmission element (not shown). The rotation drive source 68 can be mounted on the support table 4 via a suitable support frame (not shown), or can be mounted at a suitable position separately from the support table 4. An annular flange 70 is formed on the outer peripheral surface of the large diameter portion 58 of the central rotating shaft 52, and a gear 72 is fixed onto the annular flange 70.

Further, four support blocks 74 are fixed to the upper surface of the support table 4, and are positioned corresponding to the respective angular positions of the workpiece holding chuck 6 (one support block 74 is shown in FIG. 2). (Only shown) Each of these support blocks 74 is equipped with a drive coupling element including a pneumatic clutch. To be more specific, each of the support blocks 74 has a lower large-diameter cylindrical portion 76 and an upper small-diameter cylindrical portion 7.
It has 8. And, in the upper small diameter cylindrical part 78,
A substantially cylindrical rotating member 84 is rotatably mounted via bearing members 80 and 82. The lower surface of the bearing member 80 contacts the upper surface of the large diameter cylindrical portion 76, an annular spacer member 86 is disposed between the bearing member 80 and the bearing member 82, and the upper surface of the bearing member 82 contacts the inner periphery of the rotating member 84. abuts the lower surface of an annular flange 88 formed in the surface, thus bearing members 80 and 82
is held in place. Upper small diameter cylindrical part 7
An annular member 90 is fixed to the upper surface of the rotating member 8, and the lower surface of the annular member 90 restrains the annular flange 88 of the rotating member 84, thereby preventing the rotating member 84 from moving upward. Rotating member 8
An annular flange 92 is formed on the outer peripheral surface of 4, and a gear 94 is fixed onto this annular flange 92. This gear 94 is engaged with the gear 72. An annular friction plate 96 made of a material with a high friction coefficient such as synthetic rubber is fixed to the upper end of the rotating member 84. On the other hand, the lower large diameter cylindrical portion 76 of the support block 74 is formed with a circular recess 98 that is open downward. The lower surface of this circular recess 98 is closed by the support table 4, and as will become clear from the later description, the circular recess 98
8 functions as a cylinder of a pneumatic cylinder mechanism. The support block 74 is further formed with a through hole 100 that extends substantially vertically, and a shaft 102 is mounted in the through hole 100 so as to be slidable in the vertical direction. The shaft 102 extends upward beyond the upper surface of the upper small diameter cylindrical portion 78, and a bearing member 106 and a retaining ring 1 are attached to the upper end of the shaft 102.
08, the gear 110 is attached to the shaft 102 so that it cannot move in the axial direction but is rotatable. An annular protrusion 112 facing the friction plate 96 is formed on the lower surface of the gear 110. At the lower end of the shaft 102 located within the circular recess 98,
A disk 114 is fixed, which functions as a piston of a pneumatic cylinder mechanism. An elastic means 116, which may be a plurality of disc springs, is disposed between the upper surface of the support table 4 and the disc 114. On the other hand, the lower large-diameter cylindrical portion 76 of the support block 74 has an opening from the inner end opening at the upper end of the circular recess 98 to the outer peripheral surface of the lower large-diameter cylindrical portion 76. A channel 118 is formed that extends to the outer end.
The outer end of the flow path 118 is connected to an appropriate switching valve 1.
A compressed air source 124 is selectively connected to the atmosphere via a conduit 122 having 20 . When the flow path 118 is brought into communication with the compressed air supply source 124, the compressed air supplied to the circular recess 98 lowers the disk 114 to the illustrated position against the elastic biasing action of the elastic means 116. Therefore axis 1
02 and gear 110 are lowered to the connected position shown by the solid line. In such a connected position, the gear 11
An annular protrusion 112 formed on the lower surface of the gear 110 is pressed against the friction plate 96, and thus the gear 110 is frictionally connected to the rotating member 84. On the other hand, the flow path 118
When the disk 114 is made to communicate with the atmosphere, the disk 114 is raised by the elastic biasing action of the elastic means 116.
Therefore, the shaft 102 and the gear 110 are raised to the release position shown by the two-dot chain line. In this release position, the annular protrusion 112 formed on the lower surface of the gear 110 is separated upward from the friction plate 96, and thus the connection between the gear 110 and the rotating member 84 is released. Further, a gear 126 is fixed to the rotating shaft 24 to which the chuck 6 is fixed, and the gear 126 is engaged with the gear 110.

In the chuck rotating means as described above,
Common drive source 68 and multiple (4) chucks 6
A driving connection means disposed between each of the
Clutch means (friction plate 96 fixed to rotating member 84 and annular protrusion 112 formed on gear 110)
etc.). Therefore, a plurality of chucks 6
The rotation of each can be controlled separately and independently. That is, when the gear 110 is lowered to the connection position shown by the solid line, the rotation of the drive source 68 is caused by the central rotation shaft 5.
2. It is transmitted to the chuck 6 via the gear 72, the gear 94, the rotating member 84, the friction plate 96, the gear 110, and the gear 126, and thus the chuck 6 is rotated. When the gear 110 is raised to the release position shown by the two-dot chain line, the connection between the friction plate 96 and the gear 110 is released, and therefore the rotation of the chuck 6 is stopped. In order to stop the rotation of the chuck 6 as soon as the gear 110 is raised to the release position shown by the chain double-dashed line, if desired, braking means ( (not shown) may also be provided. Even though one common drive source 68 is used, the rotation of each of the plurality of chucks 6 can be controlled separately and independently. ), the three chucks 6 are rotated to grind in the grinding areas B and C.
Grinding work is carried out in the workpiece removal and mounting area A (FIG. 1), while the chuck 6 located in the workpiece removal and mounting area A (FIG. 1) is stopped and the grinding operation is carried out in the workpiece removal and mounting area A.
The workpiece removal and mounting work can be carried out in the machine, thus improving work efficiency. If desired, each of the chucks 6 can be provided with a position detector (not shown) to automatically control the engagement and disengagement of the clutch means, so that each of the chucks 6 is present at least in the grinding zones B, C and D. It is also possible to rotate the chucks 6 during this process, and to stop the chucks 6 at least while each of the chucks 6 is in the workpiece loading and unloading area A.

In the illustrated embodiment, protective covers 128, 130 and 132 are also arranged on the support table 4 by suitable support means (not shown). Such protective covers 128, 130
and 132, a cooling liquid, which may be water, used when the workpiece held on the chuck 6 is ground by the grinding wheel 8, as will be described later, or generated grinding debris is placed on the support table 4. and into the various rotational support structures and transmission elements as described above disposed therein.

In each of the grinding zones designated B, C and D in FIG. 1, a grinding wheel assembly is arranged adjacent to the support table 4 (in FIG. Only the grinding wheel 8 in the grinding wheel assembly is simply illustrated with a two-dot chain line). The construction of the grinding wheel assemblies disposed in grinding zones B, C and D may be substantially the same, with one grinding wheel assembly being shown in FIG. Second
Referring to the figures, the illustrated grinding wheel assembly, generally designated by the numeral 134, includes a stationary support base 13 positioned adjacent the periphery of the support table 4.
It has 6. A horizontally movable block 138 is mounted on the base 136 so as to be movable substantially horizontally in the left-right direction in FIG. 2 by suitable support means (not shown). Horizontal movement block 13
Preferably, the direction of movement of 8 substantially coincides with the radial direction of the support table 4. A first grindstone moving means 140 including a drive source, which may be an electric motor, is interposed between the base 136 and the horizontal moving block 138.
40 causes the horizontal movement block 138 to move. A vertically movable block 142 is attached to the horizontally movable block 138 via suitable support means (not shown) so as to be able to move up and down substantially vertically. A second grindstone moving means 144 including a drive source, which may be an electric motor, is interposed between the horizontal moving block 138 and the vertical moving block 142. The vertically moving block 142 is moved up and down. A rotating shaft 146 is rotatably mounted on the vertically moving block 142. A rotating shaft 146 protrudes downward from the vertical motion block 142.
A grinding wheel 148, preferably a so-called cup-shaped grinding wheel, is fixed to the lower end of the grinding wheel.
The illustrated grinding wheel 148 is connected to the rotating shaft 146.
An inverted cup-shaped support 150 fixed to the lower end of the
and a grinding wheel 8 fixed to the annular open end of this support 150. Grinding wheel 8
It is preferable that the support body 15 has an annular shape as a whole, but it is not limited to the shape that extends continuously in an annular shape as shown in the figure.
It is also possible to conveniently use a device which is made into an annular shape as a whole by being fixed to the annular opening end of the 0. The rotating shaft 146 is drivingly connected to a grinding wheel rotating means 152, which may be an electric motor, mounted on the vertical motion block 142, and the rotating shaft 146 and the grinding wheel 148 fixed thereto are driven by the grinding wheel rotating means 152. However, the rotating shaft 14
6 and is rotated about the central axis 154 of 6. Central axis 154 can extend substantially vertically. If desired, the central axis 154 can be inclined in a predetermined direction, for example, downward and to the right in FIG. 2 by a slight angle (for example, about 0.004 degrees to 0.01 degrees). The grinding wheel 8 itself is conveniently formed by bonding superabrasive grains, such as natural or synthetic diamond grains or cubic boron nitride grains, in any suitable manner. The abrasive grain size of the grinding wheel 8 used in the rough grinding zone B is relatively large, and the abrasive grain size of the grinding wheel 8 used in the intermediate grinding zone C is intermediate in size, and is used in the finish grinding zone D. It is preferable that the abrasive grain size of the grinding wheel 8 is relatively small.

Next, a method of surface grinding a semiconductor wafer using the surface grinding apparatus as described above will be explained.

In the first surface grinding mode, the support table 4 is rotated in the direction indicated by arrow 12 in increments of 90 degrees from the angular position shown in FIG.
Therefore, each of the four chucks 6 mounted on the support table 4 is sequentially positioned in the workpiece removal and mounting area A, the rough grinding area B, the intermediate grinding area C, and the finish grinding area D. While the chuck 6 is positioned in the workpiece removal and mounting area A, the semiconductor wafer W whose surface has already been ground as described above is placed on the chuck 6 by an appropriate removal means (not shown). taken from. Next, a new semiconductor wafer W whose surface is to be ground is placed in the first
As shown in FIG.
It is placed on top of the chuck 6 and held by suction on the chuck 6 as described above. When such a semiconductor wafer W is taken out and mounted, the clutch means (the friction plate 96 fixed to the rotating member 84, the annular protrusion 112 formed on the gear 110, etc.) is brought into the disengaged state, and the chuck is removed. 6 is stopped.

Grinding in each of grinding zones B, C and D can be accomplished as follows. Mainly referring to FIG. 1, when the rotation of the support table 4 is stopped and the support table 4 is stopped at a specific angular position, in each of the grinding areas B, C, and D, A grinding wheel 8 is located above the semiconductor wafer W that has been polished. The relative position of the grinding wheel 8 with respect to the semiconductor wafer W is
As shown in FIGS. 1 and 2, a substantially disk-shaped semiconductor wafer W (semiconductor wafer W is generally
Preferably, the grinding edge of the grinding wheel 8 passes through substantially the center of the surface of the grinding wheel (which is substantially circular except for a straight peripheral edge called an orientation flat). In order to satisfy such requirements, in FIGS. 1 and 2, the central axis of the semiconductor wafer W (extending in the direction perpendicular to the plane of the paper in FIG. 1, and extending in the vertical direction in FIG. 2) is The center axis 154 (FIG. 2) of the grinding wheel 8 is displaced radially outward of the support table 4, but if desired, it can be displaced in other directions, for example around the circumference of the support table 4 as shown in FIG. It can also be displaced in the direction. When grinding the surface of the semiconductor wafer W, the clutch means is connected and the chuck 6 and the semiconductor wafer W held thereon are moved in the direction indicated by the arrow 156 (or in the opposite direction).
For example, it is rotated at about 1 to 100 rpm.
At the same time, the grinding wheel 8 is rotated by the grinding wheel rotation means 152 (FIG. 2) in the direction indicated by the arrow 158 (or in the opposite direction) at a relatively high speed, for example, about 500 to 5000 rpm. Then, the second grindstone moving means 1
44 lowers the vertically movable block 142 at a relatively low speed, for example, 0.001 to 1.0 mm/min (FIG. 2), thus moving the grinding wheel 8 onto the semiconductor wafer W.
lower it towards. In this way, the rotating grinding wheel 8 acts on the rotating semiconductor wafer W, thereby grinding the surface of the semiconductor wafer W while gradually increasing the grinding depth. The depth of grinding of the surface of the semiconductor wafer W is defined by the amount by which the grinding wheel 8 is lowered. In such a surface grinding mode, if there is a slight deviation between the grinding edge of the grinding wheel 8 and the substantially center of the surface of the semiconductor wafer W, as is easily understood, the central region of the surface of the semiconductor wafer W Some unground protrusions remain. In such a case, by lowering the grinding wheel 8 by a predetermined amount and then reciprocating the horizontal movement block 138 over a certain range, the grinding wheel 8 can be moved a certain distance against the surface of the semiconductor wafer W. A reciprocating motion can be made over a range of minutes, thereby grinding away the non-grinding protrusions. When the surface of the semiconductor wafer W is ground as required, the grinding wheel 8 is raised and the rotation of the grinding wheel 8 is stopped. After that, the support table 4 is rotated 90 degrees.

Instead of the first surface grinding mode as described above, a second surface grinding mode as follows can also be performed. In this second surface grinding mode, at the start of grinding, as shown by the two-dot chain line 8A in FIG.
The grinding wheel 8 is positioned outside the semiconductor wafer W held on the chuck 6. The vertical position of the grinding wheel 8 is set to a required grinding depth, that is, the lower end of the grinding wheel 8 is set below the surface of the semiconductor wafer W by the required grinding depth. Then, as in the case of the first surface grinding method, the chuck 6 and the semiconductor wafer W held thereon are rotated at a relatively high speed in the direction indicated by the arrow 156 (or in the opposite direction), and the grinding wheel is rotated at a relatively high speed. 8 is rotated at a relatively high speed in the direction shown by arrow 158 (or in the opposite direction). Further, the first grinding wheel moving means 140 moves the horizontal moving block 138 to the left in FIG. 2 at a relatively low speed, for example, 100 to 500 mm/, thus moving the grinding wheel 8 to the dashed line 8A in FIG. From the position shown by arrow 16 to the position shown by two-dot chain line 8B
Move it in the direction indicated by 0. The position of the grinding wheel 8 shown by the chain double-dashed line 8B in FIG. 4 may be the same as the position of the grinding wheel 8 shown by the chain double-dashed line in FIG. In this way, the rotating grinding wheel 8 gradually acts from the periphery toward the center of the semiconductor wafer W as it moves in the direction indicated by the arrow 160, thereby grinding the surface of the semiconductor wafer W.
The grinding depth of the surface of the semiconductor wafer W is defined by the initial setting grinding depth of the grinding wheel 8.

Instead of the first and second surface grinding modes described above, a third surface grinding mode as follows can also be performed. Explaining mainly with reference to FIG. 1, in the first and second surface grinding modes, the support table 4 was stopped at a specific angle position during grinding, but in the third surface grinding mode, the support table 4 was stopped at a specific angle position. , the semiconductor wafer W held on the chuck 6
The support table 4 is moved continuously at a relatively low speed in the direction indicated by arrow 12, e.g. The semiconductor wafer W held above is rotated at a moving speed of about 100 mm/min to 500 mm/min in the direction shown by arrow 12. On the other hand, the grinding wheel 8 is set to the required grinding depth at the position shown by the two-dot chain line in FIG. 3 (or at the position shown by the two-dot chain line in FIG. The lower end of the grinding wheel 8 is set to be below the surface of the semiconductor wafer W by a required depth. As in the case of the first and second surface grinding modes, at least in the grinding areas B, C, and D, the semiconductor wafer W held on the chuck 6 is moved in the direction indicated by the arrow 156 (or in the opposite direction). At the same time, the grinding wheel 8 is rotated at a relatively high speed in the direction shown by the arrow 158 (or in the opposite direction). Thus, when the wafer W held on the chuck 6 passes the grinding wheel 8 by the continuous rotation of the support table 4, the surface of the semiconductor wafer W being rotated is It acts on and grinds. The grinding depth of the surface of the semiconductor wafer W is defined by the initial setting grinding depth of the grinding wheel 8.

Although a specific example of a surface grinding device configured according to the present invention has been described above in detail with reference to the accompanying drawings, the present invention is not limited to such specific example, and does not depart from the scope of the present invention. Of course, various modifications and modifications can be made without doing so.

<Effects of the Invention> As is clear from the above description of a specific example of the surface grinding device constructed according to the present invention, the surface grinding device constructed according to the present invention has the following effects:
When grinding the surface of a workpiece such as a semiconductor wafer W, the grinding wheel 8 is rotated and
The workpiece is also rotated. Therefore, in the illustrated example, a grinding wheel 8 having an outer diameter considerably larger than the outer diameter of the workpiece is used, but the outer diameter of the grinding wheel 8 is approximately the same as the outer diameter of the workpiece Even if it is somewhat smaller than that, the entire surface of the workpiece can be ground uniformly. Therefore, even if the diameter of the semiconductor wafer W increases, for example, it is not necessarily necessary to increase the diameter of the grinding wheel 8 accordingly. In addition, the workpiece and grinding wheel 8 during grinding
The relative movement between the grinding wheel 8 and the workpiece is defined by at least both the rotation of the grinding wheel 8 and the rotation of the workpiece. Therefore, the grinding locus of the surface of the workpiece by the grinding wheel 8 is It becomes extremely complex, extending in various directions throughout. Therefore, the grinding resistance is relatively small, the fluctuations in the grinding resistance are sufficiently small, and sufficiently uniform grinding can be performed over the entire surface of the workpiece. In addition, although one common drive source 68 is used to rotate the plurality of chucks 6, the drive coupling means between the common drive source 68 and each of the plurality of chucks 6 is Since a clutch means is incorporated in each chuck, it is possible to control the rotation of each of the plurality of chucks 6 separately and independently, while minimizing the increase in production cost. The rotation of a particular chuck is stopped to perform removal and loading of the workpiece, and during this time, the chucks are rotated in other chucks to perform grinding of the workpiece, thus improving grinding efficiency. You can force it.

[Brief explanation of drawings]

FIG. 1 is a simplified plan view showing the main components of a specific example of a surface grinding device constructed in accordance with the present invention. FIG. 2 is a sectional view showing a part of the surface grinding device shown in FIG. 1. 3 and 4 are simplified partial plan views for explaining a modification of the surface grinding style by the surface grinding device shown in FIG. 1. FIG. 4... Support table (support stand), 6... Workpiece holding chuck, 8... Grinding wheel.

Claims (1)

[Scope of Claims] 1. A support table rotatably mounted, a plurality of workpiece holding chucks rotatably mounted on the support table at intervals in the circumferential direction, and a workpiece held on the chucks. a grinding wheel rotatably mounted for grinding the surface of a workpiece, a table rotation means for rotationally driving the table, a chuck rotation means for rotationally driving the chuck, and the grinding wheel. A grinding wheel rotating means for rotating the grinding wheel is provided, and the chuck rotating means includes a common driving source and a plurality of grinding wheels respectively disposed between the common driving source and each of the chucks. drive coupling means, each drive coupling means comprising:
A surface grinding device characterized in that it has a clutch means for controlling engagement and disengagement. 2. A surface grinding device according to claim 1, wherein said clutch means is a pneumatic clutch controlled by pressurized air. 3. A patent in which one workpiece removal and loading area and a plurality of grinding areas are defined at intervals in the circumferential direction of the table, and each of the grinding areas is provided with the grinding wheel. A surface grinding device according to claim 1 or 2. 4. while each of said chucks is present at least in any of said grinding zones, said corresponding said clutch means is brought into a connected state; and while each said chuck is present at least in said workpiece removal and loading zone; 4. A surface grinding device according to claim 3, wherein the corresponding clutch means are placed in a disengaged condition. 5. Any one of claims 1 to 4, wherein the grinding wheel has an annular shape as a whole, and the center axis of rotation of the grinding wheel is arranged substantially parallel to the center axis of rotation of the chuck. The surface grinding device described in . 6. The grinding wheel is mounted so as to be movable in the direction of its rotation center axis, and is provided with a grindstone moving means for moving the grinding wheel in the direction of its rotation center axis. When grinding the surface of the workpiece with the grinding wheel,
The table is stopped at a predetermined angular position where the workpiece held on the chuck is in a predetermined relationship with the grinding wheel, and the grinding wheel is moved toward the chuck by the grinding wheel moving means. is,
6. The surface grinding apparatus according to claim 5, wherein the depth of grinding of the surface of the workpiece is gradually increased. 7. The workpiece is approximately disk-shaped, and when the table is stopped at the predetermined angular position, the grinding wheel is moved so that the outer peripheral edge of the grinding wheel passes through substantially the center of the surface of the workpiece. 7. The surface grinding device according to claim 6, wherein the workpiece is positioned against. 8. When the surface of the workpiece held on the chuck is ground by the grinding wheel, the table is continuously rotated by the table rotation means, and thus the workpiece held on the chuck is 6. The surface grinding apparatus according to claim 5, wherein a processed workpiece is passed through the grinding wheel. 9. The grinding wheel is mounted so as to be movable in a direction substantially perpendicular to its rotational center axis, and a grindstone moving means is provided for moving the grinding wheel in a direction substantially perpendicular to its rotational center axis. When the surface of the workpiece held on the chuck is ground by the grinding wheel, the table is stopped at a predetermined angular position, and the grinding wheel is held on the chuck. The grindstone is moved by the grinding wheel moving means from the periphery of the processed workpiece toward the center, and thus the surface of the workpiece is gradually ground from the periphery toward the center. surface grinding equipment. 10. The workpiece has a substantially disk shape, and the grinding wheel is moved by the grindstone moving means to a position where the outer peripheral edge of the grinding wheel passes through substantially the center of the surface of the workpiece. The surface grinding device according to item 9. 11. The surface grinding apparatus according to any one of claims 1 to 10, wherein the workpiece is a semiconductor wafer.