JP3533128B2 - Work holding device and double head grinding machine - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is applied to a processing device for processing a disk-shaped work such as a silicon wafer or a glass disk, and relates to a work holding device for holding the work in a rotated state. The present invention also relates to a double-sided grinder equipped with this work holding device.

[0002]

2. Description of the Related Art Conventionally, a double-headed grinder has been known as an apparatus for processing a disk-shaped thin work. This double-headed grinder is equipped with a pair of cup-shaped grindstones in which the grinding action surfaces face each other coaxially and in parallel, and a drive mechanism for rotating each of these grindstones coaxially at a high speed. The double-sided grinder also includes a work holding device that holds the work while rotating it and inserts the work between both grindstones.

In this double-headed grinding machine, while the work holding device inserts the work between the two grindstones, the grindstones are brought into close proximity to each other while being rotated at a high speed, so that both surfaces of the work are Grind all areas evenly.

The work holding device has a plurality of rollers which are in contact with the edges of the work and rotate the work, and the front and back surfaces of the work which are opposed to each other so that the work is not displaced in the central axis direction. It has a pair of support pads for rotatably guiding.

Each of these support pads is for supporting the work so as not to be displaced in the direction of the central axis, and is known to be of a roller holding type and a hydrostatic pressure holding type. Each support pad by the roller holding method has a plurality of rollers rotatably abutting on the front and back surfaces of the work in a rotated state.

On the other hand, each support pad of the hydrostatic pressure holding system has a plurality of fluid supply holes opened on the surface of each support pad facing the work. Then, each support pad ejects fluid from the fluid supply hole and is urged toward each other. Then, the work is rotatably supported by each of the support pads via the hydrostatic film formed between the work and each of the support pads.

[0007]

The double-sided grinder equipped with the work holding device according to the prior art described above is used for grinding a work which has been flattened to a certain extent in advance. That is, this double-sided grinder is for processing a workpiece which has been flattened to some extent by a lapping machine or the like in advance.

For example, in the process of processing a silicon wafer, a wafer cut into a disk shape from an ingot with a wire saw or the like is first flattened to some extent by a lapping machine. Then, the double-sided grinder grinds the wafer processed by the lapping machine to make the surface of the wafer flatter and the thickness thereof to a predetermined thickness with high precision.

The wafer cut out by the wire saw is substantially flat on both sides. However, due to some abnormality during the cutting process with the wire saw, streaky unevenness may be partially generated on the wafer surface. For this reason, the processing by the lapping machine is required in advance before the processing by the double-headed grinding machine.

If a wafer having an uneven surface is put on a double-sided grinder, the following problems will occur. This problem occurs regardless of whether the work holding method of the support pad in the work holder is the roller holding method or the hydrostatic pressure holding method.

That is, when the support pad is of the roller holding type, the uneven portion of the wafer in the rotated state hits each roller of the support pad to cause these rollers to dance and the wafer itself vibrates violently. Therefore, the wafer will be damaged or the surface will not be finished flat.

On the other hand, when the support pad is of the hydrostatic pressure holding type, this support pad cannot support the wafer while rotating it. That is, in order for the hydrostatic pressure to operate normally, the gap between the support pad and the wafer must be several tens of μm or less. For this reason, if the gap partially opens beyond this value due to the unevenness of the work, the fluid rapidly flows out from that portion, and the hydrostatic pressure does not act.

Therefore, in order for all the wafers in various states cut out by the wire saw to be processed normally, the processing by the lapping machine or the like must be performed in advance before the processing by the double-headed grinding machine. The process was complicated.

Therefore, even if there are irregularities on the front and back surfaces of a work such as a wafer, the work can be held correctly, and therefore processing by a lapping machine or the like is unnecessary, and It is an object of the present invention to provide a double-sided grinder equipped with this work holding device.

[0015]

In order to solve the above-mentioned problems, the work holding device and the double-sided grinder according to the present invention have the following configurations.

That is, according to the work holding device of the present invention, a disk-shaped work to be machined is inserted between both working surfaces of a working device having a pair of working surfaces that face each other in parallel and rotate coaxially. In the work holding device, a frame capable of accommodating the work and a predetermined area on each of the front and back surfaces of the work stored in the frame, with the inner surface facing the predetermined area at the edge of the work, respectively. A pair of support pads, which are provided on the frame so as to be opposed to each other and capable of approaching or separating from the work respectively, and ejecting a fluid to each surface of the work, and the support pads are provided so as to be close to each other. Regulated state in which the gap between the urging pad urging mechanism and each of the support pads is not less than a predetermined regulation interval, or a release state in which this regulation is released. A stopper portion which takes one of the states of a workpiece drive section for rotating said workpiece, characterized by comprising.

With this structure, when the support pads are biased by the pad biasing mechanism and the stopper portion is in the regulated state, the spacing between the support pads is maintained at the regulation spacing. In this state, the work is mechanically guided between the support pads. Here, when the stopper portion is released, each support pad approaches the work by the pad biasing mechanism. Then, a hydrostatic film is formed between this work and each support pad. That is, the work is supported between the support pads by the hydrostatic pressure.

The pad urging mechanism and the stopper portion are
It may have a mechanism driven by pneumatic pressure or hydraulic pressure, or may have a mechanism driven by an electric motor and a spring.

Further, the stopper portion is fixed to each of the support pads and has an abutment portion capable of restricting each of the support pads by abutting an end portion thereof against the frame. Good. Further, the regulation interval may be set to be equal to or larger than the maximum thickness of the unworked work. Further, each of the support pads may have a groove-shaped pocket formed on the surface facing the work, and an ejection hole for ejecting a fluid into the pocket.

The double-headed grinding machine of the present invention is an inner ring portion which is formed rotationally symmetrical to the work holding device and is displaceable in the direction of the central axis thereof. A first spindle device having an outer ring part rotatable about a central axis of the inner ring part in a state where the part does not rotate, and a cup-type grindstone fixed to the outer ring part having a flat working surface formed therein. The cup-shaped grindstone has the same construction as that of the first spindle device, and the working surface of the cup-shaped grindstone is arranged parallel and coaxially to the working surface of the cup-shaped grindstone in the first spindle device. And a second spindle device.

Further, in this double-headed grinder, the work holding device holds the work and inserts the work between the working surfaces of the cup-shaped grindstones of the both spindle devices. The pad urging mechanism urges the support pads so that they are close to each other, and while maintaining the interval between the support pads at a predetermined regulation interval by the stopper portion, the spindle devices of the cup-shaped grindstones are maintained. The working surfaces are brought close to each other until a predetermined switching interval is reached, and when the working surface of each of the cup-shaped grindstones reaches this switching interval, the restriction of the stopper portion is released and the work is placed between the support pads. While maintaining the fluid static pressure, the working surfaces of the cup-shaped grindstones are further approximated by the both spindle devices until a predetermined finishing interval is reached. A control device for, may be provided.

[0022]

DETAILED DESCRIPTION OF THE INVENTION An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic configuration diagram showing a double-sided grinder according to the present embodiment. This double-headed grinder is the first
The spindle device 1 and the second spindle device 2, and the work holding device 3 are provided.

The first spindle device 1 has a cup-shaped grindstone 11 and an outer ring portion 12 for rotating the grindstone 11 at a high speed. The cup-shaped grindstone 11 has a tip end surface formed into a ring-shaped flat surface, and this flat surface serves as a grinding operation surface.

Further, the spindle device 1 has an inner ring portion 13 having a rotationally symmetric outer shape, the tip of which protrudes in a cylindrical shape. Although the inner ring portion 13 does not rotate, it can move in the central axis direction by a drive mechanism (not shown). The outer ring portion 12 is fitted on the outer side of the inner ring portion 13 so as to be rotatable at high speed around its central axis. And the whetstone 11 is
The center axis is made to coincide with the rotation axis of the outer ring portion 12 and is fixed to the tip of the outer ring portion 12.

The outer ring portion 12 is driven by a motor (not shown) to rotate at high speed, thereby rotating the grindstone 11 at high speed. In this state, when the inner ring portion 13 moves in the central axis direction, the outer ring portion 12 moves together with the inner ring portion 12 while rotating at a high speed. Therefore, the grindstone 11 can also move in the rotation axis direction while rotating at a high speed.

The second spindle device 2 has the same structure as the first spindle device 1. That is, the spindle device 2 includes a grindstone 21, an outer ring portion 22, and an inner ring portion 2
Have three.

Each of the spindle devices 1 and 2 is fixed on the bed 4 in a state where the grindstones 11 and 21 are coaxially opposed to each other. In addition, as shown in FIG.
The direction parallel to the central axes of the two grindstones 11 and 21 (the left-right direction in FIG. 1) is the Z direction. Then, the respective spindle devices 1 and 2 are driven by a drive mechanism (not shown) to drive the inner ring portions 13 and 23.
Can be moved in the Z direction. When each of the inner ring portions 13 and 23 moves in the Z direction, the outer ring portion 12,
22 will also move in the Z direction. Therefore, in a state where the grindstones 11 and 21 are fixed to the outer ring portions 12 and 22, respectively, the operator can freely adjust the interval between the grindstones 11 and 21.

In the plane perpendicular to the Z direction, the direction horizontal to the floor surface is the X direction, and the direction perpendicular to the X direction is the Y direction. That is, in FIG. 1, the direction perpendicular to the paper surface is the X direction, the vertical direction is the Y direction, and the horizontal direction is the Z direction.

The work holding device 3 has a work holder 31 for holding the work W while rotating it, and a holder moving mechanism 32 for arranging the work holder 31 between the spindle devices 1 and 2. The structure of the work holder 31 will be described later.

The holder moving mechanism 32 has a flat table and a connecting member for attaching the work holder 31 to the table. The table of the holder moving mechanism 32 is slidable in the X direction on a bed 4 below the outer ring portions 12 and 22 of the spindle devices 1 and 2 facing each other in a plane parallel to the floor surface. It is arranged. The holder moving mechanism 32 can slide the work W held by the work holder 31 between the grindstones 11 and 21 by sliding in the X direction. The position of the work holder 31 when the work W is inserted between the grindstones 11 and 21 is called a grinding position.
Further, the position of the work holder 31 when the work W is retracted from the position between the grindstones 11 and 21 to a predetermined position is referred to as a retracted position.

Next, the structure of the work holder 31 in the work holding device 3 will be described. FIG. 2 is a configuration diagram showing the work holder 31. Further, FIG. 3 is a view of FIG. 2 viewed in the III direction. Note that FIG. 2 partially shows the first spindle device 1 together with the work holder 31, but FIG. 3 only shows the work holder 31. As shown in these figures, the work holder 31 includes a frame 311, a pair of support pads 312, 3
12 and a work drive unit 313.

The frame 311 has a substantially C-shaped holding portion 311 in which a notch capable of accommodating the work W is formed in a state of being opposed to a region of substantially the outer circumference of the work W.
a, and a mounting portion 311b protruding outward from the central portion of the outer periphery of the holding portion 311a.

Further, the holding portion 311 of the frame 311
In a, a plurality of rollers R1 and R that abut on the edge of the work W in a state where the work W is stored in the notch.
2, R3, R4 are attached. The roller R1 and the roller R4 are arranged symmetrically with respect to the central axis of the holding portion 311a. Further, the roller R2 and the roller R3 are arranged inside the rollers R1 and R4, respectively, symmetrically with respect to the central axis of the holding portion 311a.

Further, at one end of the holding portion 311a,
A first work support mechanism H1 is attached. First
The work supporting mechanism H1 includes a substantially V-shaped link member H11, a roller H12, and a cylinder portion H13. The link member H11 has a bent portion,
It is rotatably supported by the tip of the holding portion 311a. In addition, the link member H11 has a bent portion at the holding portion 3
It is arranged toward the inside of 11a. Further, the link member H11 can be rotationally displaced within the plane of FIG.

The roller H12 is pivotally supported at one end of the link member H11. The other end of the link member H11 is connected to the cylinder part H13,
The link member H is driven by the cylinder portion H13.
11 is rotationally displaced. And this link member H11
Is rotationally displaced, so that the roller H12 moves to the holding portion 3
Either the holding position that rotatably abuts the edge of the work W stored in 11a or the open position that is separated from the work W is taken.

Similarly, the second work support mechanism H2 includes a link member H21, a roller H22, and a cylinder portion H23.
And is attached to the other end of the holding portion 311a.
The work W is inserted into and removed from the holding portion 311a of the frame 311 in a state where the cylinders H13 and H23 have the rollers H13 and H23 at the open positions via the link members H11 and H21, respectively.

Each of the support pads 312 and 312 is formed in a flat plate shape and has a holding portion 311a of the frame 311.
When the work W is accommodated therein, the work W has a shape capable of facing a substantially semicircular region on each of the front and back surfaces of the work W on the side close to the support portion 311b.

Further, each of the support pads 312 and 312 is
Each of the three engaging ends 31 protruding outward of the frame 311
2a. Each of these engaging end portions 312a is attached to the holding portion 311a of the frame 311 near the central portion and both ends thereof by guide portions G described later. In addition, each of the support pads 312 and 312 has a holding portion 3
It has a shape in which its tip is cut out in a gentle arc shape so as not to interfere with the central portion of the work W stored in 11a.

Further, each of the support pads 312 and 312 has a plurality of pockets P respectively formed on the surfaces facing each other. Each pocket P is a shallow and flat groove, and a supply hole for ejecting a pressurized fluid is opened in the central portion thereof.

Then, in the state where the work W is held in the holding portion 311a, the support pads 312 and 312 are held.
Respectively face the work W with a slight gap. In this state, the fluid is supplied to each pocket P through the supply hole. Then, this fluid is filled in each pocket P, and each support pad 312,
It flows through the gap between the workpiece 312 and the work W. That is,
The work W is located between the support pads 312 and 312.
It will be held by the hydrostatic pressure. As the fluid, water or other grinding liquid can be used.

The work driving unit 313 is a driving belt 313.
a, a work drive motor and a speed reducer. The drive belt 313a is wound around a pulley fixed to the output shaft of the decelerator and rollers R2 and R3. In addition,
When the decelerator is driven by the work drive motor, the rollers R2 and R3 are driven via the drive belt 313a and rotate in the same direction.

The work holder 31 is attached to the holder moving mechanism 32 at its attachment portion 311b so that the work W is parallel to the grinding surfaces of the grindstones 11 and 21 when holding the work W. Has been.

In addition, as described above, the holder moving mechanism 32
Can slide the work holder 31 in the X direction in FIG. That is, the work holder 31 is
While holding the work W, it can move in the left-right direction (X direction) in FIG.

Note that FIG. 2 shows the work holder 31 in the grinding position. In this state, the work W held in the work holder 31 has the leftmost end in FIG. 2 at the inner ring portion 1 of each spindle device 1, 2.
It is arranged so as to reach the vicinity of the center of 3,23. At this time, the central portion of the work W is arranged at a position facing the grindstones 11 and 21.

Further, a third work support mechanism H3 is attached to the inner ring portion 13 of the spindle device 1.
The work support mechanism H3 includes a pair of support rollers H31,
Has H32. These rollers H31 and H32 are, in the state where the work holder 31 is placed at the grinding position,
The workpiece W held by the workpiece holder 31 is arranged so as to rotatably abut on the left end of FIG.

Next, a method of attaching the support pads 312 and 312 of the work holder 31 to the frame 311 will be described. As shown in FIG. 2, each support pad 312 is attached by three guide portions G respectively arranged near the center portion and both ends of the holding portion 311a of the frame 311. Further, stopper portions S, which will be described later, are attached to the respective support pads 312 and 321 near the respective guide portions G.

FIG. 4 is a sectional view showing the vicinity of the guide portion G of the work holder 31. Note that FIG. 4 includes a line connecting the center of the guide portion G in the central portion of the holding portion 311a and the center of the adjacent stopper portion S in FIG.
Is a sectional view taken along a plane perpendicular to the paper surface of FIG.

Each of the support pads 312 and 312 has its engaging end portion 31 when the surfaces facing each other are brought into close contact with each other.
The space between the 2a and 312a is the holding portion 3 of the frame 311.
It is formed so as to be approximately equal to the thickness of 11a.

The guide portion G has a guide pin G1 and a pair of opening / closing mechanisms G2 and G2. Guide pin G1
Is formed in a columnar shape, and is fitted and fixed so that both ends thereof symmetrically project into a mounting hole formed in the holding portion 311a of the frame 311. In addition, each support pad 3
A through hole having an inner diameter slightly larger than the outer diameter of the guide pin G1 is formed in each of the engaging end portions 312a of the cables 12, 312. Then, each support pad 312, 312
Are arranged so as to face each other in a state in which the guide pins G1 are inserted into the through holes of the respective engaging end portions 312a.

Each opening / closing mechanism G2 as a pad urging mechanism
G2 is a cylinder G21, G21, and a piston G2
2 and G22 respectively. Each cylinder G21, G21
Have a prismatic outer diameter, but the inside has a shape equivalent to that of a hollow cylinder. And
On the base end side of each cylinder G21, G21, a base end side through hole that communicates with the internal cylindrical space is formed.
Further, on the tip end side of each of the cylinders G21, G21, a tip end side through hole communicating with the inner cylindrical space is formed.

Each of the pistons G22, G22 has a large-diameter portion formed in a cylindrical shape, a small-diameter base end portion that coaxially protrudes toward the base end side of the large-diameter portion, and a small diameter portion that coaxially protrudes toward the tip end side. Has a tip of. In addition, each piston G22, G2
2 has a large-diameter portion inscribed in the inner walls of the cylinders G21 and G21, and a base end portion of the cylinder G2.
1, G21 are inscribed in the base end side through holes, and the tip portions thereof are inscribed in the tip end side through holes of the cylinders G21, G21.

In this state, each cylinder G21, G
The base ends of the pistons G22 and G22 project at the base ends of the pistons 21, respectively. Further, the tip ends of the pistons G22 and G22 respectively project from the tip ends of the cylinders G21 and G21. The base end portions of the pistons G22, G22 are coaxially and integrally fixed to the tip ends of the guide pins G1. Also, male threads are cut at the tip of each piston G22, G22, and these male threads are
Each pair of nuts N, N are fitted together. Further, each of the cylinders G21 and G21 is screwed and fixed to the support pads 312 and 312 by screws (not shown) at the base end portions thereof.

Then, in each cylinder G21, G21,
A base end side air hole A1, which is opened on the base end side with respect to the cylindrical space inside thereof, and a tip side air hole A2 which is opened on the tip side in the cylindrical space inside thereof, are formed.

An electromagnetic valve (not shown) is attached to each of the air holes A1, A1, A2 and A2. A tube (not shown) to which compressed air is supplied is attached to each of these solenoid valves. And each solenoid valve can supply the compressed air from a tube to each air hole A1, A1, A2, A2, respectively. The state of each air hole A1, A1, A2, A2 when air is supplied is called a pressurizing state. Further, each solenoid valve has a corresponding air hole A1, A1, A2, A
2 can be communicated with the outside air. The state of each air hole A1, A1, A2, A2 communicated with the outside air is called an exhaust state. That is, each air hole A1, A1,
Each of A2 and A2 can be in a pressurized state or an exhausted state.

When the base end side air holes A1 and A1 of the cylinders G21 and G21 are in a pressurized state and the tip end side air holes A2 and A2 are in an exhausted state, the pistons G2 are
Since G2 and G22 are fixed to the guide pin G1, the cylinders G21 and G21 move inward. Therefore, the support pads 312 and 312 are moved by being guided by the guide pin G1 and come close to each other. The state of each support pad 312, 312 in this case is called a proximity state.

When the base end side air holes A1 and A1 of the cylinders G21 and G21 are in an exhaust state and the tip end side air holes A2 and A2 are in a pressurized state, each cylinder G2 is
1, G21 respectively move to the tip side. Therefore, the support pads 312 and 312 are moved by being guided by the guide pin G1 and separated from each other. The state of each support pad 312, 312 in this case is called a separated state. Note that the cylinders G21, G21 are restricted from displacing toward the tip side by hitting the nuts N, N on the outside thereof. Therefore, each support pad 312,
In the separated state, 312 is in a state with a predetermined gap. This distance is set between the support pads 312,
Between the 312, the interval is set to be sufficient for inserting the work W.

In the vicinity of the guide portion G thus constructed, a pair of stopper portions S, S respectively attached to the support pads 312, 312 are arranged. These stopper portions S, S are respectively cylinders S1, S
1 and stopper pistons S2 and S2.

The cylinders S1 and S1 have the same structure as the cylinders G21 and G21 in the opening / closing mechanisms G2 and G2. The stopper pistons S2 and S2 are the pistons G22 and G2 of the opening and closing mechanisms G2 and G2.
The structure is substantially the same as that of No. 2 except for the base end portion. That is, the base end portions of the stopper pistons S2, S2 are the pistons G2 of the opening / closing mechanisms G2, G2.
2, G22 is longer than the base end, and the peripheral edge of the end is smoothly chamfered. The end faces of the stopper pistons S2, S2 on the base end side are abutting faces (abutting portions) for abutting against the holding portion 312a of the frame 311 as described later.

Further, through holes corresponding to the stoppers S, S are formed near the guide portion G in the engaging ends 312a, 312a of the support pads 312, 312, respectively. Then, the stoppers S, S respectively support the support pads 312, 32 at the base end portions of the cylinders S1, S1 in a state where the base end portions of the stopper pistons S2, S2 are fitted into the through holes, respectively. The engaging end portion 312 of 312
It is being fixed to a and 312a. That is, each of the cylinders S1 and S1 has the engagement end portion 31 at the base end portion thereof.
2a and 312a are screwed and fixed by screws (not shown).

The outer diameter of the base end portion of each stopper piston S2, S2 is slightly smaller than the inner diameter of the through hole in the engaging end portion 312a, 312a of each support pad 312, 312. Therefore, each stopper piston S
2, 2 can be moved in the axial direction by being guided by each through hole.

That is, when the base end side air holes A1 and A1 of each cylinder S1 and S1 are pressurized and the tip end side air holes A2 and A2 are exhausted, each stopper piston S
2 and S2 move outward respectively. The state of each stopper S, S in this case is called a retracted state. It should be noted that FIG. 4 shows the stopper portions S, S in the retracted state. In this retracted state, each stopper portion S, S
Of the stopper pistons S2 and S2, respectively.
It is retracted into the through hole in 312a.

On the other hand, when the base end side air holes A1 and A1 of each cylinder S1 and S1 are exhausted and the tip end side air holes A2 and A2 are pressurized, each stopper piston S
2 and S2 respectively move to the base end side. Then, the stopper pistons S2, S2 respectively have nuts N, N screwed into their tip portions but abut against the outside of the cylinders S1, S1, so that the abutting surfaces thereof are respectively engaged end portions 312a, 31.
It is arranged in a state of being projected inward of 2a. The state of each stopper portion S, S in this case is referred to as a protruding state. The amount of protrusion of the abutting surfaces of the stopper pistons S2, S2 inside the engaging end portions 312a, 312a is
It is possible to adjust each nut N, N.

The protruding state of each of the stopper portions S and S corresponds to a regulated state in which the distance between the support pads 312 and 312 is regulated so as not to be less than a predetermined regulation distance. The retracted state of each of the stopper portions S, S corresponds to the released state in which this regulation is released.

Next, the control system of the double-sided grinder will be described. FIG. 5 is a block diagram schematically showing the control system of the double-headed grinder. As shown in FIG. 5, the double-sided grinder includes the spindle devices 1 and 2 and the work driving unit 31 described above.
3, and a controller 5 connected to the holder moving mechanism 32, respectively.

The control device 5 controls the spindle devices 1 and 2 to rotate the outer ring parts 12 and 22 at high speeds, respectively, and bring the inner ring parts 13 and 23 close to or away from each other. . In addition, the control device 5
Controls the work drive unit 313 in the work holder 31 of the work holding device 3 to work the work belt 313a.
Each roller R2, R3 is rotated via the
Can rotate. Further, the control device 5 can control the holder moving mechanism 32 of the work holding device 3 to move the work holder 31 to the grinding position or the retracted position.

The work supporting mechanisms H1 and H2 in the work holder 31 are arranged in the respective cylinder portions H13 and H13.
It is connected to a support mechanism driving unit D that drives each H23. The support mechanism drive unit D is connected to the control device 5. Then, the control device 5 can control the support mechanism driving unit D to arrange the rollers H12 and H22 at the open position or the holding position.

The guide portion G of the work holder 31 has the air holes A1 and A2 of the cylinders G21.
It has a cylinder drive part G3 for the guide part G that can control the solenoid valve that communicates with and that can supply compressed air. Further, the stopper portion S of the work holder 31 controls a solenoid valve communicating with the air holes A1 and A2 of the cylinders S1 and S1 of the workpiece holder 31 and includes a cylinder drive portion S3 for the stopper portion S that can supply compressed air. Have. These cylinder drive parts G3 and S3 are connected to the control device 5, respectively.

Then, the control device 5 controls the cylinder drive portion G3 to set the support pads 312 and 312 to the close state or the separated state, and controls the cylinder drive portion S3 to set the stopper portion S. It can be set to the protruding state or the separated state.

The operation of this embodiment will be described below. 6 to 8 are explanatory diagrams showing the operations of the guide portion G and the stopper portion S in the work holder 31, and these drawings will be referred to together.

First, when the unprocessed work W is loaded into the work holder 31, the control device 5 causes the holder moving mechanism 32 to dispose the work holder 31 at its retracted position, and the supporting mechanism drive unit D supports each work. The rollers H12 and H22 of the mechanisms H1 and H2 are respectively arranged at the open position, and the guide portion G is driven by the cylinder driving portion G3 to set the support pads 312 and 312 in the separated state. In this state, the work W conveyed by a robot (not shown) is inserted between the support pads 312 that are wide open. FIG. 6 shows the work holder 31 immediately after the work W is inserted.

Then, the control device 5 causes the support mechanism drive unit D to move the rollers H1 of the respective work support mechanisms H1 and H2.
2, H22 are respectively arranged in the closed position, and the holder moving mechanism 32 arranges the work holder 31 in the grinding position.

Further, the control device 5 has a cylinder driving section G
3, the guide part G is set in the proximity state, and
The cylinder drive portion S3 sets the stopper portions S, S to the protruding state, respectively. FIG. 7 shows the work holder 31 in this state. As shown in FIG. 7, the stopper piston S in each stopper portion S, S
Since the abutting surfaces of S2 and S2 abut the holding portions 311a of the frame 311, respectively, the support pads 312 and 3
The two 12 are opposed to each other with a predetermined restriction interval therebetween. The regulation interval is set wider than the maximum thickness of the unworked work W.

Then, the control unit 5 has the work drive unit 31.
Each roller R2, R3 is rotated by 3. Then, the work W has its edges surrounded by the rollers R1 to R4, H12, and H.
Each roller R while being in contact with 22, H31, H32
2, it will be driven by R3 and rotate on its axis. In addition,
At this time, each pocket P of each support pad 312, 312
A fluid is supplied to both of these support pads 31.
Since the space between 2 and 312 is wide open, the fluid only flows out and the workpiece W cannot be held by the static pressure. In this state, the work W is not supported by the hydrostatic pressure, but is supported by both support pads 31.
2, 312 are mechanically guided, and their displacement in the central axis direction is restricted.

Here, the control device 5 brings the inner ring parts 13 and 23 close to each other in a state where the outer ring parts 12 and 22 of both spindle devices 1 and 2 are rotated at high speed. Then, the grindstones 11 and 21 of the spindle devices 1 and 2 respectively bring their grinding action surfaces into contact with the respective surfaces of the work W, and start the first grinding step. Since the work W is rotating, the entire area of each surface is uniformly ground. Even if there are large irregularities on the surface of the work W, the irregularities are flattened in the first grinding step.

Then, the control device 5 controls both grindstones 11 and 21.
The second grinding step is started when the interval of 1 reaches a predetermined switching interval. That is, the control device 5 sets the respective stopper portions S, S to the retracted state by the cylinder drive portion S3. FIG. 8 shows the work holder 31 in this state.

As shown in FIG. 8, the support pads 312 and 312 try to approach each other without being interfered by the stoppers S and S. However, since the fluid is ejected from the support pads 312 and 312, the support pads 312 and 312 do not contact the work W. That is, since the work W is flattened in the first grinding step, each support pad 31
The fluid supplied to the pockets P of the second and third 312 can form a static-state hydrostatic film between the respective support pads 312 and 312 and the work W. For this reason,
The work W is moved to the respective support pads 312, 3 by the hydrostatic pressure.
It is supported in a rotating state without abutting on 12.

Further, the control device 5 has the inner ring portions 13 and 23.
The second grinding step is continued by bringing the two into close proximity to each other. Then, the control device 5 ends the second grinding step when the interval between the two grindstones 11 and 21 reaches a predetermined finishing interval. In this state, each surface of the work W is finished perpendicular to the center axis and flat. The thickness of the finished work W is 1
It is equal to the finishing interval between 1 and 21.

Then, the control device 5 causes the spindle devices 1 and 2 to separate the inner ring portions 13 and 23 from each other, and the cylinder driving portion G3 drives the guide portion G to bring the support pads 312 and 312 into the separated state. Set. Further, the control device 5 causes the holder moving mechanism 32 to move the work holder 31 to its retracted position. After that, the control device 5 causes the support mechanism drive unit D to drive each support mechanism H1,
The rollers H12 and H22 of H2 are arranged at the open position, respectively. In this state, the robot (not shown) carries out the finished work W. The discharged work W will be processed in the subsequent cleaning and drying steps.

As described above, since the work W is ground in the mechanically guided state in the first step,
Even if there is a large unevenness on the surface, it can rotate between the support pads 312 and 312 in the state of being opened at the regulation interval, and the entire area on each of the front and back surfaces is evenly ground. Therefore, large irregularities on the front and back surfaces of the work W are flattened in the first grinding step.

The work W that has undergone this first grinding step is
Since each of the surfaces is flattened, in the second grinding step, it can be supported by the hydrostatic pressure and rotate without contacting the support pads 312, 312. For this reason, the work W is finished by grinding the entire region of each surface evenly to obtain a desired shape and state.

That is, the double-sided grinder of this embodiment can process a work W having a large stripe-shaped unevenness in a cutting process with a wire saw into a desired shape. Therefore, the pretreatment which was previously performed by the lapping machine or the like becomes unnecessary, and the production process of the silicon wafer or the like is simplified and speeded up.

[0082]

According to the work holding device of the present invention configured as described above, it is possible to hold a work between both support pads by hydrostatic pressure, and to mechanically hold this work between both support pads. Will be able to guide you.

Further, according to the double-headed grinder equipped with this work holding device, the first grinding step is performed while the work is mechanically guided between the two support pads, and then the work is fluidized between the two support pads. The second grinding step can be performed in a state of being held by static pressure. Therefore, even if the work has unevenness, this unevenness is
Since it is flattened in the second grinding step, the work is correctly held between the two support pads by the hydrostatic pressure in the second grinding step.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram showing a double-sided grinder according to an embodiment of the present invention.

FIG. 2 is a configuration diagram showing a work holder.

FIG. 3 is a view of FIG. 2 viewed in the III direction.

FIG. 4 is a cross-sectional view showing the vicinity of a work holder guide portion.

FIG. 5 is a block diagram schematically showing a control system of a double-sided grinder.

FIG. 6 is an operation explanatory view of a guide portion and a stopper portion in the work holder.

FIG. 7 is an operation explanatory view of the guide portion and the stopper portion in the work holder.

FIG. 8 is an operation explanatory view of the guide portion and the stopper portion in the work holder.

[Explanation of symbols] 1, 2 spindle device 11,21 grindstone 12,22 Outer ring part 13,23 Inner ring 3 Work holding device 31 Work holder 311 frames 312 Support pad 313 Work drive unit G guide section G1 guide pin G2 opening / closing mechanism S stopper H3 support mechanism H31, H32, R1-R4 rollers W work

─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Akio Iwase 5-2 Sokai-cho, Niihama-shi, Ehime Sumitomo Heavy Industries, Ltd. Niihama Works (56) Reference Japanese Patent Laid-Open No. 9-262747 (JP, A) Kaihei 10-217079 (JP, A) JP 11-11497 (JP, A) JP 11-77497 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) B24B 7 / 17 B24B 41/06

Claims (4)

(57) [Claims] 1. A work holding apparatus for inserting a disk-shaped work to be machined between two working surfaces of a working apparatus having a pair of working surfaces that face each other in parallel and rotate coaxially with each other. With the inner surface facing a predetermined area on the edge of the work, a frame that can store the work, and a predetermined area on each of the front and back surfaces of the work stored in the frame and facing the work. And a pair of support pads which are provided on the frame so as to be able to approach or separate from each other and eject a fluid to each surface of the work, and a pad biasing mechanism capable of biasing the respective support pads so as to approach each other. , A restriction state in which the interval between the support pads is regulated so as not to be less than or equal to a predetermined regulation interval, or a release state in which the regulation is released. A work holding device comprising: a pawl section and a work drive section that rotates the work. 2. The stopper portion is fixed to each of the support pads, and has an abutment portion capable of restricting each of the support pads by abutting an end portion thereof against the frame. The work holding device according to claim 1, which is characterized in that. 3. The work holding device according to claim 1, wherein the regulation interval is set to be equal to or larger than the maximum thickness of the unworked work. 4. A work holding device according to any one of claims 1 to 3, an inner ring portion which is formed rotationally symmetrically and is displaceable in the direction of its central axis, and is fitted to the outer side of this inner ring portion. With
A first outer ring part that is rotatable about the central axis of the inner ring part when the inner ring part is not rotating, and a cup-shaped grindstone that has a flat working surface and is fixed to the outer ring part. A spindle device and a structure similar to that of the first spindle device, and arranged such that the working surface of the cup-shaped grindstone is parallel and coaxially opposed to the working surface of the cup-shaped grindstone in the first spindle device. The second spindle device and the work holding device hold the work and insert the work between the working surfaces between the cup-shaped grindstones of both spindle devices, with the pad of the work holding device. An urging mechanism urges the support pads so that they are close to each other, and the stopper portions are regulated so that the intervals between the support pads are set to a predetermined value. While maintaining the regulation interval, the working surfaces of the cup-shaped grindstones are brought close to each other by the both spindle devices until a predetermined switching interval is reached,
When the working surface of each cup-shaped grindstone reaches this switching interval, the stopper portion is released and the workpiece is held between the support pads by hydrostatic pressure, and the cup-shaped wheels are supported by the spindle devices. A double-head grinding machine comprising: a control device that further brings the working surfaces of the grindstones closer to each other until a predetermined finishing interval is reached.