JP2000280155A - Double surface grinder for thin circular workpiece - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a double surface grinder for a thin circular workpiece capable of grinding at high precision regardless of thickness reduction of the workpiece. SOLUTION: This grinder is provided with a pair of grinding wheels 8, 9 disposed in such a way that their end grinding surfaces face each other, and that they are relatively moved to each other in the axial directions, and a workpiece rotating means provided to support a workpiece at a grinding position between the grinding surfaces to be rotated so that both surfaces of the workpiece to be worked respectively face the grinding surfaces of the grinding wheels 8, 9, that an outer circumference of the workpiece crosses outer circumferences of the grinding surfaces, and that the center of the workpiece is positioned inside the grinding surfaces. The rotating means is provided with hydrostatic type axial direction support means 10, 11 to supply fluid from between the grinding wheels 8, 9 to both surfaces of the workpiece to be worked at outer parts for contactlessly supporting the workpiece in the axial directions. The hydrostatic type axial direction supporting means 10, 11 are provided with a hydrostatic control means 13 for keeping hydrostatic pressure constant to correspond to reduction of thickness of the workpiece as grinding goes on.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for grinding both sides of a thin disk-shaped work, and more particularly to an apparatus for simultaneously grinding both sides of a thin disk-shaped work such as a semiconductor wafer.

[0002]

2. Description of the Related Art As an apparatus for simultaneously grinding both surfaces of a thin disk-shaped work, there is an apparatus described in Japanese Patent Application Laid-Open No. 10-217079, for example.

This grinding apparatus is provided on a horizontal bed and on the upper surface of the bed at intervals on the left and right sides, and a pair of vertical disk-shaped grindstones whose opposing surfaces are ground surfaces, and a thin vertical disk-shaped workpiece. The work is supported at the grinding position between the grinding surfaces so that both sides of the work face the grinding surface of the grindstone, and the outer periphery of the work intersects the outer periphery of the grinding surface and the center of the work is located within the grinding surface. A work rotating device for rotating the work.

[0004] The work rotating device includes a static pressure axial support device that supplies fluid to both surfaces of a portion of the work that is out of the space between the grinding wheels and supports the work in a non-contact manner in the axial direction by the static pressure. A radial support drive device that supports and rotates the work in the radial direction.

[0005] The static pressure axial support device has a support block in which a slit into which a work can be inserted is formed, and a fluid such as air is blown out from both sides of the block forming the slit, and the static fluid generated by the fluid is generated. The work is supported by the pressure.

[0006]

However, the conventional grinding apparatus cannot cope with a change in the thickness of the workpiece caused by the grinding. That is, when the thickness of the work is reduced by the progress of the grinding, the static pressure is reduced and the work becomes unstable. Therefore, there is a problem that the grinding accuracy of the work is reduced and the flatness of the processed surface of the work is reduced.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problem, and to provide a double-sided grinding apparatus for a thin disk-shaped work capable of grinding with high accuracy regardless of a decrease in the thickness of the work. It is in.

[0008]

Means for Solving the Problems and Effects of the Invention In order to solve the above-mentioned problems, a double-sided grinding apparatus for a thin disk-shaped work according to the present invention has a circular grinding surface of an end surface facing each other and a relative axial grinding direction. A pair of grinding wheels arranged and rotated so as to be able to move, and the processing surfaces on both surfaces of the thin disk-shaped work respectively oppose the grinding surfaces of the pair of grinding wheels, and the outer periphery of the work is Work rotation means that intersects with the outer periphery of the grinding surface and supports the work at a grinding position between the grinding surfaces so that the center of the work is located within the grinding surface, and that rotates the work, A static pressure type axial support means for supplying fluid to the processing surfaces on both surfaces of the portion of the work which is outside from between the grinding wheels, and for supporting the work in an axially non-contact manner by the static pressure; And the word In the double-sided grinding machine for thin disk-shaped workpieces, which has a radial support driving means for supporting and rotating the workpiece in the radial direction, the hydrostatic axial support means can cope with a decrease in the thickness of the workpiece as the grinding progresses. And a static pressure control means for keeping the static pressure constant.

In this double-sided grinding apparatus for a thin disk-shaped work, the value of the static pressure for holding the work is kept constant irrespective of the change in the thickness of the work. Can be ground.

In the above-mentioned double-sided grinding apparatus for a thin disk-shaped work, the hydrostatic axial support means has a pair of fluids each having a surface facing a surface of the part of the work protruding out from between the grinding wheels. Having a supply member, the static pressure control means,
Moving means for moving at least one fluid supply member in the axial direction of the work, the moving means having a fluid pressure cylinder, the fluid pressure cylinder being moved in response to a decrease in the thickness of the work as grinding proceeds. When the rod is extended, at least one fluid supply member may move in the axial direction of the workpiece, and the static pressure may be kept constant.

In this device, the static pressure control means can be realized with a simple configuration, and the static pressure can be easily maintained constant, and the static pressure can be controlled reliably. .

Further, the above-mentioned double-side grinding device includes a vacuuming device connected to one fluid supply member, and only the other fluid supply member is moved by a hydraulic cylinder. After the work,
In some cases, it can be held in a state of being adsorbed.

In this apparatus, if the surface of the fluid supply member facing the surface of the portion of the work protruding outside from between the grinding wheels is correctly made vertical, the work can be accurately placed vertically by the fluid supply member. Since the work can be supported in a non-contact manner after being held by suction, the work can be accurately maintained in a vertical state even in a non-contact state.

[0014]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a grinding apparatus for a thin disk-shaped work according to the present invention.

FIGS. 1 to 4 show a double-sided grinding apparatus for a thin disk-shaped work according to a first embodiment of the present invention. In the following description, the front, rear, left and right are based on FIG. 1, the left and right of FIG. 1 are referred to as left and right, and the front side of the paper of FIG.

The grinding device (1) comprises a frame (3) having front and rear surfaces attached to the upper surface of a horizontal bed (2) and a work insertion opening (3a) formed in the upper surface, and a frame (3).
(3) is provided with a pair of left and right bases (4) and (5) arranged such that the vertical surfaces face each other.

On the left and right inner surfaces of the frame (3), grindstone heads (6) and (7) are respectively mounted to face each other through the left and right bases (4) and (5). On the opposing surface of the grinding wheel heads (6) and (7), cylindrical grinding wheels (8) and (9) extending in the left-right direction,
Make sure that the circular grinding surfaces on the end face
(8) They are arranged so that the axes of (9) are located on the same straight line. Although not shown, the grindstone heads (6) and (7)
(8) An axial moving device for moving the (9) in the left-right direction and a rotating device for rotating the grindstones (8) and (9) around the axis are provided. Note that the whetstones (8) and (9) are
(8) and (9) are located at a standby position where the mutual interval is larger than the thickness of the work (w).

The right and right bases of the left base (4)
On the left side of (5), a pair of fluid supply members (10) and (11) are provided to face each other. The fluid supply members (10) and (11) include a short cylindrical member (10e) (11e) and a lid member (10
f) and (11f), each of which has a disk shape having an axis extending in the left-right direction as a whole, and a notch (10c ) Is formed. In addition, fluid supply members (10) (1
1) is provided with a large number of fluid ejection holes (10a) (11a). The holes (10a) and (11a) are connected via spaces (10b) and (11b) provided in the supply members (10) and (11), and the spaces (10b) and (11b) are not shown. The fluid supply devices described above are connected to each other, and fluid is ejected from the holes (10a) (11a). The left fluid supply member (10) has a plurality of work suction holes (10d). This hole (1
0d) is a fluid ejection hole (10a) in the supply member (10).
The space (10g) is separated from a space (10b) connecting the space (10b), and a suitable evacuation device such as a vacuum pump (not shown) is connected to the space (10g) via a connection pipe (23). I have.

The left fluid supply member (10) is fixed to the right surface of the left base (4), while the right fluid supply member (1) is fixed.
1) is provided movably in the left-right direction as described below.

The fluid supply member (11) is a vertical plate-like support member (1).
2). The support member (12) is a rod (1) of two air cylinders (13) having a rod (13a) extending in the left-right direction.
3a) Mounted at the tip. The air cylinder (13) is fixed to the base (5) at intervals in the front and back.
On the right side of the support member (12), a cylindrical guide member (14) extending in the left-right direction at the lower front corner and the upper rear corner is attached,
The guide member (14) slidably penetrates through the base (5) so that the fluid supply member (11) moves correctly in the left-right direction. The support member (12) has a whetstone
There is a through hole (12a) through which (9) penetrates.
In addition, the right fluid supply member (11), when not grinding,
The rod (13a) of the air cylinder (13) is located at the standby position where it is in the most contracted state. The air cylinder (13)
Is connected to a compressed air supply source via a pressure adjusting valve (not shown), and the pressure in the air cylinder (13) is kept constant by the pressure adjusting valve.

The left base (4) is provided with a radial support drive device for radially supporting and rotating the work held by the fluid supply member (11) as follows.

A fluid supply member is provided on the right side of the left base (4).
Rollers (15) (16) (17) located in front and back around (10) (11)
However, there are provided a total of six, two each at the top, middle, and bottom. Each of the rollers (15), (16) and (17) is rotatable about a horizontal axis extending in the left-right direction, and further, the interval between the lower two rollers (15) is equal to that of the two inner rollers (15). 16), the four rollers (15) and (16) can receive and support the work (w) in a vertical state.

The two inner rollers (16) are drive rollers, and the electric motor mounted on the left base (4).
(22) is driven via a belt (19). The lower two rollers (15) are driven rollers.
The upper two rollers (17) are holding rollers, which are not shown, but can be moved back and forth by a moving device such as an air cylinder.
(17) can take a standby position where the distance between the rollers (17) is larger than the diameter of the work.

Although not shown in detail, an autoloader (21) as a work loading / unloading means for automatically loading and unloading the workpiece (w) in the grinding device is provided above the frame (3). I have.

In this grinding apparatus, the work
The diameter of the fluid supply members (10) and (11) is slightly smaller than the diameter of the fluid supply members (10) and (1).
1) smaller than the diameter.

In the grinding apparatus (1) having such a configuration, the work is performed with the holding roller (17), the grinding wheels (8) and (9) and the right fluid supply member (11) in the standby position. (w) is a vertical position with the drive roller (16) and the driven roller (1
5) and put on. Next, the inside of the left fluid supply member (10) is evacuated, and the work (w) is sucked and adsorbed on the right surface of the left fluid supply member (10), and is maintained in an accurate vertical state. At this time, the upper half of the work (w) is located between the fluid supply members (10) and (11). The upper part of the work (w) projects slightly above the fluid supply members (10) and (11), and the mutual interval between the press rollers (17) is adjusted so as to press a part of this part of the work (w). Adjusted.

As soon as the left fluid supply member (10) and the evacuation device are shut off, the left and right fluid supply members (10) (1)
From 1), a fluid such as air or coolant flows out of the part of the work (w) located between the fluid supply members (10) and (11), that is, between the grinding wheels (8) and (9). The work (w) is supplied to the two processing surfaces of the work (w) and the work (w) is supported at the grinding position. At the same time, the rod (1
3a) extends and the right fluid supply member (11) moves to the left,
The static pressure between the fluid supply members (10) and (11) is set to a predetermined value, and the workpiece (w) is vertically supported in a non-contact manner by the static pressure.

In the above state, the drive roller (16) starts rotating, and the work (w) rotates by the frictional force between the drive roller (16) and the outer periphery of the work (w). When the work (w) starts time, the left and right grinding wheels (8) and (9) are rotated. The left and right grindstones (8) and (9) are simultaneously rotated and moved toward the other grindstones (8) and (9), respectively.
Is sandwiched between the grinding wheels (8) and (9). In this way, the outer periphery of the work (w) intersects with the outer periphery of the grinding surface of the grindstones (8) and (9), and the center of the work (w) is located within the grinding surface of the grindstones (8) and (9). .

In this state, while the work (w) makes one rotation, the entire processing surface on both sides of the work (w) passes between the grinding surfaces of the grindstones (8) and (9). The right grinding wheel (9) gradually moves to the left as the grinding progresses. On the other hand, the whetstone (8) on the left
(w) Do not move from the position sandwiching. And the right whetstone (9)
Is stopped for a predetermined time at a position where the mutual interval with the left grindstone (8) becomes a value determined by the finished thickness of the work (w), and spark-out grinding is performed. Then, the work (w) is ground to a predetermined thickness from the thickness at the time of loading.

When the work (w) is ground, the pressure in the air cylinder (13) is kept constant, so that as the thickness of the work (w) decreases, the fluid supply members (10) and (11) As soon as the static pressure of the air cylinder (13) decreases, the rod (13a) of the air cylinder (13) extends by the reduced thickness of the work (w), and the fluid supply members (10) (11)
The static pressure in between is returned to a predetermined value. Since this operation is performed with little time difference, the static pressure is kept substantially constant.

When the grinding of the work (w) is completed, the grinding wheel (8)
(9) moves away from the work (w) to the standby position. Whetstone
When (8) and (9) move away from the work (w), the drive roller (16) is stopped, whereby the work (w) also stops rotating. When the work (w) stops rotating, the fluid supply member (10)
The supply of the fluid from (11) is stopped. At the same time, the work (w) is sucked into the right surface of the left fluid supply member (10). Then, the upper edge of the work (w) is held by the loader (21), and the pressing roller (17) and the right fluid supply member (11) move to the standby position. Then, the work (w) is lifted upward by the loader (21) and is carried out of the grinding device (1). This operation is repeated, and grinding is performed one after another.

As in the above-described grinding apparatus (1), one grindstone (the left grindstone (8) in the above-described embodiment) is stopped and used as a reference, and the other grindstone (the right grindstone (in the above-described embodiment) is used). If 9) is moved, the grinding can be performed with reference to the grinding surface of one of the grinding wheels, so that the grinding accuracy is increased.

Further, one fluid supply member (the right fluid supply member (11) in the above embodiment) is moved, and the other fluid supply member (the left fluid supply member in the above embodiment) is moved.
If (10)) is fixed and the static pressure is kept constant, the static pressure can be kept constant with high accuracy and the configuration of the device can be simplified.

The loading and unloading of the work (w) and the work (w)
The procedure supporting (w) is not limited to the procedure described above.

Next, a double-side grinding apparatus according to a second embodiment of the present invention will be described with reference to FIGS.
In the following description, the same components and portions as those of the grinding device according to the first embodiment are denoted by the same reference numerals, and description thereof is omitted. Further, in the following description, the left and right in FIG.

This grinding device (20) differs from the grinding device (20) in the means for attaching the fluid supply members (25) and (26) to the base (4) and the support member (12) and in the means for radially supporting and driving.

The left fluid supply member (25) is attached to the right side of the base (4), and the right fluid supply member (26) is attached to the support member (12) as follows.

The left and right fluid supply members (25) and (26) have three through holes (25a) and (26a) formed at intervals in the circumferential direction. Insert the through hole (25a) of the left fluid supply member (25) into the base
The three stud bolts (29) screwed into (4) insert the through holes (26a) of the right fluid supply member (26) into the three stud bolts (30) screwed into the support member (12). Respectively penetrate. Nuts (31) are screwed to the left and right sides of the fluid supply members (25) and (26) of the stud bolts (29) and (30) via spherical washers (36), respectively. The distance between the left fluid supply member (25) and the base (4) and the distance between the right fluid supply member (26) and the support member (12) are adjusted to be the same, and the fluid supply member (25 ) (26) is maintained exactly vertically.

In this embodiment, a radial support driving means for supporting the work (w) in the radial direction and rotating it is formed as follows.

Between the left and right fluid supply members (25) and (26),
A work fitting member (33) having a vertical disk shape and having a hole (33d) into which a work (w) is fitted is provided in the center. The fitting member (33) is based on three support rollers (32) that rotate around a horizontal axis that extends in the left-right direction.
(4), and the fitting member (33) is supported by the roller (32). Note that the support rollers (3
2) are arranged at equal intervals in the circumferential direction of the fitting member (33).

The work fitting member (33) is made up of a thick peripheral edge (33a) with gear teeth cut on the outer periphery, and a work holding part (33b) protruding radially inward therefrom.
The thickness of the work holding portion (33b) is smaller than the thickness of the work (w). In the present embodiment, the peripheral portion (33a) and the work holding portion (33b) are formed by different members, and the peripheral portion (33
a) and the work holding part (33b) are screwed to each other.

The teeth of the peripheral portion (33a) mesh with gears fixed to the motor shaft of a drive motor (34) attached to the base (4), and the fitting member (33) is driven by the drive motor (34).
Are driven to rotate in the axial direction.

A projecting portion (33c) projecting radially inward is formed on the inner edge of the work holding portion (33b).
The projection (33c) conforms to the shape of a notch (wa), which is a so-called notch, formed on the periphery of the work (w).

In the grinding device (20), a work (w) is carried in and out by a loader (35) provided slightly above the center of the device (20), as described below.

The loader (35) is provided with a suction cup (35a), and the work (w) is sucked onto the suction cup (35a) such that the notch (wa) is located at a predetermined position, in this apparatus, at the upper side. ing. On the other hand, the work fitting member (33) is
The protrusion (33c) of 3b) is in a state of being on the upper side.

When the grinding wheels (8) and (9) and the right fluid supply member (26) are in the standby positions, respectively,
5) is lowered and the center of the hole (33d) of the holding part (33b)
(w) is located on the same horizontal straight line extending in the left-right direction. Next, the loader (35) moves to the left, and the work (w) is inserted into the hole (33d) so that the projection (33c) of the holder (33b) fits into the notch (wa) of the work (w). It is fitted in.
Thereafter, the work (w) separates from the suction cup (35a), and the loader (35) moves to the upper right of the grinding device (20). The unloading of the work (w) is performed in reverse of the above procedure.

The procedure in which the grindstones (8) and (9) and the right fluid supply member (26) are moved to perform grinding is the same as in the case of the grinding apparatus of the first embodiment.

[Brief description of the drawings]

FIG. 1 is a partially cutaway front view of a double-side grinding apparatus for a thin disk-shaped work according to a first embodiment of the present invention.

FIG. 2 is an enlarged cross-sectional view of a main part of the double-side grinding apparatus for the thin disk-shaped work.

FIG. 3 is a side view of the double-side grinding apparatus for the thin disk-shaped work.

FIG. 4 is a perspective view of a main part of the double-side grinding apparatus for the thin disk-shaped work.

FIG. 5 is a front view of a part in a double-sided grinding machine for a thin disk-shaped work according to a second embodiment of the present invention.

FIG. 6 is a side view of the double-side grinding device.

[Explanation of symbols]

 (1) Grinding device (8) (9) Grinding wheel (10) (11) Fluid supply member (13) Air cylinder (13a) Rod (20) Grinding device (25) (26) Fluid supply member (w) Work

Claims (3)

[Claims] 1. A pair of grinding wheels arranged and rotated so that end circular grinding surfaces are opposed to each other and are relatively movable in an axial direction, and a processing surface on both surfaces of a thin disk-shaped work is provided. The work is interposed between the grinding surfaces such that the outer periphery of the work intersects the outer periphery of the grinding surface and the center of the work is located within the grinding surface while facing the grinding surfaces of the pair of grinding wheels. Work rotation means for supporting and rotating at a grinding position of the work, wherein the work rotation means supplies a fluid to the processing surfaces on both surfaces of a part of the work that is out of between the grinding wheels. Both surfaces of a thin disk-shaped work comprising: a static pressure type axial support means for supporting the work in a non-contact manner in the axial direction by the static pressure; and a radial support drive means for supporting the work in the radial direction and rotating on its own axis. Smell grinding equipment Characterized in that the static pressure type axial support means is provided with a static pressure control means for keeping a static pressure constant in response to a decrease in the thickness of the work as the grinding progresses, wherein double-sided grinding of a thin disk-shaped work is provided. apparatus. 2. The static pressure type axial support means has a pair of fluid supply members each having a surface opposed to a surface of a portion of a work protruding outside from between the grinding wheels, and the static pressure control means is provided. Moving means for moving at least one fluid supply member in the axial direction of the work, the moving means having a fluid pressure cylinder, and the fluid pressure cylinder corresponding to a decrease in the thickness of the work as grinding proceeds. 2. The thin disk-shaped member according to claim 1, wherein at least one of the fluid supply members is moved in the axial direction of the work by extending the rod, and the static pressure is kept constant. Workpiece double-side grinding machine. 3. A vacuum pump connected to one of the fluid supply members, and only the other fluid supply member is moved by a fluid pressure cylinder. 3. The double-sided grinding apparatus for a thin disk-shaped work according to claim 2, wherein the apparatus is capable of holding the workpiece in a state where the workpiece is held.