JP2000033560A - Double-side polishing machine - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To suitably cope with an increase in the size of an apparatus, it is possible to make an upper surface plate heavier and to increase the rotation speed of the upper surface plate, thereby maintaining high polishing accuracy and polishing efficiency. Can be improved. SOLUTION: A carrier 12 in which a thin plate is provided with a through hole 12a, and a wafer 10 arranged in the through hole 12a of the carrier 12 are vertically sandwiched and moved relatively to the wafer 10 for polishing. Upper surface plate 14 and lower surface plate 1
6, the carrier 12 is caused to make a circular motion that does not rotate in a plane parallel to the plane of the carrier 12, and the upper surface plate 14 is moved in the through hole 12a.
And a carrier rotating mechanism 20 for rotating the wafer 10 held between the lower platen 16 and the lower platen 16, and abutting against the upper platen 14 to prevent the upper platen 14 from swinging in a direction parallel to the surface of the carrier 12. And a roller 62.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a double-side polishing apparatus. Conventionally, as a double-side polishing apparatus, a processing material (hereinafter, referred to as a "work") is formed by rotating an external gear (hereinafter, referred to as an "external gear") and an internal gear (hereinafter, referred to as an "internal gear") at different angular velocities. The carrier corresponding to the planetary gear carrying the above-described carrier is rotated and revolved, and the upper and lower stools having polishing surfaces arranged above and below the carrier sandwich the work from above and below and relative to the work. There is one using a planetary gear mechanism that moves and grinds. This double-side polishing device is used as a lapping device (lapping machine) or polishing device. It has high accuracy and can simultaneously polish both surfaces, so that the processing time is short, and a thin material polishing process such as a silicon wafer used as a semiconductor chip material is completed. Suitable for.

[0002]

2. Description of the Related Art A configuration of a polishing apparatus using a conventional planetary gear mechanism will be described with reference to FIG. 11
Reference numeral 2 denotes an upper surface plate, and 114 a lower surface plate. A polishing cloth (cloth) is attached to each surface, and a polishing surface is formed by the polishing cloth. 116 is an external gear, 118
Is an internal gear. Reference numeral 120 denotes a carrier. A work 121 is held in a through hole formed in the carrier 120, and rotates by meshing with an external gear 116 and an internal gear 118. The upper stool 112 is connected to an upper stool 112a, and the shaft 1 suspended from the upper stool 112a.
A gear 112c is provided at the tip of 12b. Gear 1
Reference numeral 12c denotes an idle gear 112d and an idle gear 1
12d meshes with the gear 112e. This gear 112
e is provided coaxially with the spindle 126 so as to rotate integrally with the spindle 126. The lower platen 114 is provided with a gear 114b coaxially provided with a spindle 126 via a gear 114a provided coaxially with the lower platen 114.
Connected to. The external gear 116 is connected to the spindle 12 via a gear 116 a provided coaxially with the external gear 116.
6 is connected to a transmission gear 116b coaxially provided. The internal gear 118 is connected to a transmission gear 118b provided coaxially with the spindle 126 via a gear 118a provided coaxially with the internal gear 118. That is,
The polishing apparatus includes an external gear 116, an internal gear 118, an upper surface plate and a lower surface plate 112, and a single driving device.
This is a so-called four-way drive system in which the drive 14 is driven to rotate. Note that the spindle 126 is a variable speed reducer 132
The variable speed reducer 132 is connected to a motor 134 via a belt 136,
6 is controlled.

According to the polishing apparatus using the planetary gear mechanism, for example, the gear 116a is set so that the angular velocity of the internal gear 118 becomes larger than the angular velocity of the external gear 116.
And the rotation ratio of the transmission gear 116b and the rotation ratio of the gear 118a and the transmission gear 118b, respectively.
The carrier 120 meshed between the external gear 116 and the internal gear 118 revolves in the same direction as the rotation direction of the internal gear 118 (for example, "counterclockwise") and rotates clockwise. The lower platen 114 also rotates counterclockwise, while the upper platen 112 rotates clockwise due to the presence of the idle gear 112d. Note that the rotation direction and rotation speed of the carrier 120 can be changed by setting the angular velocities of the external gear 116 and the internal gear 118 according to the polishing conditions.

[0004] In addition, the front and back polished surfaces of the workpiece 121 are
A liquid abrasive containing abrasive particles and the like is supplied, and the work of the liquid abrasive is suitably polished. In polishing a silicon wafer, an abrasive (generally called “slurry”) in which abrasive grains are dispersed in an alkaline polishing liquid is usually supplied between the silicon wafer and a polishing surface of a polishing platen to perform polishing. You. As a method of supplying a liquid abrasive, a liquid abrasive is dripped from above using a pump power and gravity through an abrasive supply hole provided vertically penetrating the upper platen 112. It is generally made to supply. The liquid abrasive discharged from the abrasive supply hole is supplied to a polishing section where the polishing surface of the upper platen 112 comes into contact with the work 121 and polishes the work 121, and is supplied between adjacent carriers 120. , And flows onto the polishing surface of the lower platen 114, and is supplied to a polishing section for polishing the work 121 by bringing the polishing surface of the lower platen 114 into contact with the work 121.

FIG. 10 is a plan view illustrating an example of the arrangement of the carriers 120 according to the polishing apparatus shown in FIG. 11, and there is a gap A between adjacent carriers 120. This gap A exists in both the inner diameter portion and the outer diameter portion with a sufficient width,
The liquid abrasive is also suitably supplied onto the polishing surface of the lower platen 114. As described above, the liquid abrasive is sufficiently supplied to both surfaces of the work 121 by a simple supply unit from above. According to this polishing apparatus, since the liquid abrasive can be suitably supplied and the carrier 120 can be moved in a complicated manner, the work 121 (for example, a silicon wafer) can be uniformly polished while preventing uneven polishing. Therefore, the flatness of the work can be improved. Work 12
Since both surfaces can be simultaneously polished, the polishing efficiency can be improved.

However, in the double-side polishing apparatus using the above-mentioned conventional planetary gear mechanism, the carrier 120 is mounted on the external gear 11.
6 and the internal gear 118, it is difficult to cope with the recent increase in size of the work 121 such as a silicon wafer. That is, it is impossible to make the diameter of the carrier 120 larger than the radius of the surface plate, and the polished surface of the surface plate cannot be used efficiently. In addition, in a conventional double-side polishing apparatus using a planetary gear mechanism, a complicated gear mechanism is used, and it is difficult to increase the size of the apparatus. Costs increase in various aspects.

Therefore, the present applicant has developed the following double-side polishing apparatus as a background art. That is, the double-side polishing apparatus sandwiches a carrier having a thin plate with a through hole and a wafer, which is a plate-shaped work arranged in the through hole of the carrier, from above and below and relative to the wafer. A double-side polishing apparatus comprising an upper surface plate and a lower surface plate for moving and polishing the carrier, wherein the carrier is caused to make a circular motion that does not rotate in a plane parallel to the surface of the carrier via a carrier holder, and the through hole is provided. And a carrier rotating mechanism for rotating the wafer held between the upper and lower stools within the carrier. In addition, the upper surface plate and the lower surface plate are each provided so as to perform a rotation (rotation).

[0008]

However, in the above-described polishing apparatus of the background art, there is a problem that the upper platen easily vibrates in the horizontal direction. That is, the upper stool rotates in a fixed position, while the carrier performs an eccentric turning motion. For this reason, the upper platen receives a frictional force of a workpiece such as a wafer moving by the carrier. The friction force is a force for swinging the upper platen in the horizontal direction. In particular, when the rotation axis for suspending and rotating the upper platen becomes longer, the upper platen is more likely to vibrate due to the relationship of the moment. . When the weight of the upper stool is increased due to an increase in the size of the upper stool, the natural frequency of the suspended portion including the upper stool becomes a low value, and the vibration is more likely to occur. In addition, when the number of revolutions of the upper platen is increased, in the worst case, the upper platen resonates and the wafer is broken.

Therefore, an object of the present invention is to suitably cope with an increase in the size of the apparatus, to make the upper platen heavier and to increase the rotation speed of the upper platen, and to maintain high polishing accuracy. An object of the present invention is to provide a double-side polishing apparatus capable of improving polishing efficiency.

[0010]

To achieve the above object, the present invention has the following arrangement. That is, the present invention
A carrier in which a thin plate is provided with a through-hole, an upper platen for sandwiching a plate-shaped work arranged in the through-hole of the carrier from above and below, and relatively moving and polishing the work; The lower platen and the carrier are caused to make a circular motion that does not rotate in a plane parallel to the plane of the carrier, and the work held between the upper platen and the lower platen is swirled in the through hole. And a carrier rotating motion mechanism for causing the upper surface plate to abut against the upper surface plate, wherein vibration preventing means for preventing the upper surface plate from swinging in a direction parallel to the surface of the carrier is provided. Features.

Further, the vibration preventing means comprises a plurality of guide rollers abutting on the outer periphery of the upper platen, so that the vibration preventing means can be suitably provided.

Further, the vibration preventing means comprises a concave portion provided at a central portion of the upper platen and a convex portion provided at a central portion of the lower platen so as to be fitted in the concave portion. Vibration preventing means can be suitably provided. .

The upper platen and the lower platen are driven to rotate about an axis parallel to a direction perpendicular to the surface of the carrier, so that the work and the upper platen and the lower platen are relatively moved. The movement can be complicated and the polishing accuracy can be improved.

[0014] The carrier turning mechanism may further include a carrier holder for holding the carrier, and a holder-side shaft having an axis parallel to a direction perpendicular to a surface of the carrier and being axially mounted on the carrier holder. And a base-side shaft which is parallel to the holder-side shaft and is attached to the base at a predetermined distance from the base-side shaft, and the holder-side shaft is turned around the base-side shaft. By providing the carrier holder with a crank member that makes a circular motion that does not rotate with respect to the base, and a rotation drive device that rotates the crank member about an axis on the base side, the carrier holder has a simple configuration. It is possible to make the held carrier make a circular motion that does not preferably rotate.

Also, a plurality of the crank members are provided,
The shafts on the base side are linked by a synchronization means such as a timing chain so that the plurality of crank members circularly move in synchronization with each other, so that the carrier can be suitably and stably moved with a simple configuration. it can.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below in detail with reference to the accompanying drawings. FIG. 1 is an exploded perspective view schematically showing one embodiment of a double-side polishing apparatus according to the present invention, and FIG. 2 is a side sectional view showing a positional relationship of each component when the embodiment of FIG. FIG. The present embodiment is a double-side polishing apparatus for polishing a silicon wafer 10 which is a plate-shaped work. An upper surface plate 14 and a lower surface plate 16 for sandwiching the wafer 10 from above and below and moving it relative to the wafer 10 for polishing.
And A polishing cloth 14a, 16a called a cloth is attached to each surface of the upper surface plate 14 and the lower surface plate 16, and a polishing surface is formed by the polishing cloths 14a, 16a. Further, the upper stool 14 and the lower stool 16 of the present embodiment are driven to rotate about an axis parallel to a direction orthogonal to the surface of the carrier 12. The wafer 10 is circular and is loosely fitted in the circular through-hole 12a.
It has a size that allows it to rotate freely. The carrier 12 is generally formed of, for example, a glass epoxy plate, and is generally set to have a thickness of about 0.7 mm for the wafer 10 having a thickness of 0.8 mm.

Reference numeral 20 denotes a carrier rotating mechanism for moving the carrier 12 in a plane parallel to the plane of the carrier 12 and held between the upper platen 14 and the lower platen 16 in the through hole 12a. 1 is an example of a movement mechanism for moving a wafer 10 that has been moved. Carrier turning mechanism 20 in the present embodiment
Causes the carrier 12 to make a circular motion that does not rotate in a plane parallel to the plane of the carrier 12, and to pivotally move the wafer 10 held in the through-hole 12 a and sandwiched by the upper platen 14 and the lower platen 16. Let it. That is, when the thickness of the carrier 12 is not considered, the carrier 12 is caused to make a circular motion that does not rotate in the same plane as the plane of the carrier 12. The specific configuration of the carrier turning mechanism 20 will be described below.

A carrier holder 22 is formed in a ring shape and holds the carrier 12. Here, the connecting means 50 for connecting the carrier 12 and the carrier holder 22 will be described. FIGS. 3A and 3B are explanatory views (FIG. 3A is a plan view and FIG. 4B is a cross-sectional view) illustrating the overall configuration of an example of the carrier 12 and the carrier holder 22, and FIG. It is a principal part expanded sectional view. The linking means 50 connects the carrier 12 with the carrier 1
2 is held by being connected to a carrier holder 22 so that the carrier 2 does not rotate and absorbs the elongation of the carrier 12 due to thermal expansion. Connecting means 50 of the present embodiment
Then, as shown in FIG. 4, a pin 23 provided on the carrier holder 22 side and the carrier 1 for loosely fitting the pin 23 are provided.
2 is provided with a hole 12b provided with a clearance in a direction in which the carrier 12 expands due to thermal expansion (in this embodiment, a radial direction of the circular carrier 12). The clearance of the hole 12b may be suitably provided at least in a direction in which the carrier 12 expands due to thermal expansion.
What is necessary is just to be formed in a long hole.

In this embodiment, the carrier 12
The inner peripheral surface 22a of the carrier holder 22 is arranged so that the outer peripheral edge thereof can be suitably slid when thermally expanded.
Is formed so as to generate a clearance between the first and second members.
That is, the outer diameter of the carrier 12 is smaller than the inner diameter of the inner peripheral surface 22a by a predetermined dimension. The hole 12b of the carrier 12, which is provided with a clearance in consideration of the thermal expansion of the carrier 12 as described above, is directly set by being fitted to the pin 23 of the carrier holder 22. By providing the connecting means 50 for absorbing the expansion of the carrier 12 due to the thermal expansion, the carrier 12 can be suitably connected to the carrier holder 22 with a simple configuration in a state where the carrier 12 is prevented from rotating. Thereby, the elongation of the carrier 12 can be suitably released and absorbed, and the deformation of the carrier 12 can be prevented. Further, since the carrier 12 is configured to be mounted by being fitted to the carrier holder 22, the operation at the time of mounting is simplified.

Next, the function of adjusting the height of the carrier 12 provided in the carrier holder 22 will be described. 23a
Is a flange portion, which is integrally provided in the middle of the pin 23 in a washer shape. This flange portion 23a
The supporting portion is provided on the carrier holder 22 side and directly supports the carrier 12 to hold it. Pin 2
A screw 23b is provided below the third flange 23a so that the pin 23 can be attached to the lower step 22b of the carrier holder 22.
Is provided. The height of the flange portion 23a can be adjusted by adjusting the degree of screwing of the screw portion 23b into the lower portion 22b of the carrier holder 22. By providing the flange portion 23a in this manner, the height position of the carrier 12 can be suitably adjusted, and the carrier 12 can be appropriately held by the carrier holder 22.

That is, by adjusting the height of the flange portion 23a, it is possible to suitably cope with a change in conditions, such as when the polishing pad 16a of the lower platen 16 is worn out and becomes thin.
At about the same height as the surface of the polishing pad 16a of No. 6, the carrier 12 can be suitably held so as not to be bent. Accordingly, the carrier 12 can be suitably held horizontally, and cracking of the wafer 10 and deterioration of polishing accuracy can be prevented. Further, the outer peripheral surface of the carrier 12 is partially received by the surface of the flange portion 23a, and the carrier 1
2 can be suitably supported by sliding due to expansion and contraction. That is, since the contact area between the outer peripheral surface (lower surface) of the carrier 12 and the upper surface on the side of the carrier holder 22 can be reduced, the sliding friction resistance can be reduced, and the carrier 12 can slide favorably. Thereby, the expansion and contraction force of the carrier 12 due to heat or the like is suitably released, and the occurrence of distortion of the carrier 12 can be prevented.

In the above embodiment, the support height of the carrier 12 is adjusted by adjusting the height of the flange portion 23a of the pin 23. However, the present invention is not limited to this. The configuration is not particularly limited as long as it is a suitable means capable of supporting the 12 at a predetermined height.
For example, a mechanism for raising and lowering the carrier holder 22 itself may be provided, and the supporting portion for supporting the carrier 12 may be basically the upper surface of the lower portion 22b of the carrier holder 22. The upper surface of the lower portion 22b may be provided with irregularities in order to improve the slipperiness.

Next, another linking means according to the present invention will be described with reference to FIG. FIG. 5A is a plan view,
FIG. 5B is a sectional view. As is apparent from the drawing, this embodiment differs from the above embodiment only in the linking means 50. The linking means 50 includes an internal gear-shaped engaged portion 52 provided on the carrier holder 22 side, and An external gear-shaped engaging portion 42 is provided on the carrier 12 so as to engage with the engaged portion 52 with play. That is, the gear provided on the outer periphery of the carrier 12 and the gear provided on the inner periphery of the ring-shaped carrier holder 22 are engaged with play with play. This also makes it possible to suitably connect the carrier 12 to the carrier holder 22 with a simple configuration. And the same effect as the above embodiment can be obtained.

Next, an embodiment of each structure of the carrier turning mechanism 20 will be described with reference to FIGS. Reference numeral 24 denotes a crank member, which has an axis parallel to the axis L of the upper stool 14 and the lower stool 16, and a shaft 24 a on the holder side which is mounted on the carrier holder 22, and a shaft center on the shaft 24 a on the holder side. Are provided with a base-side shaft 24b which is parallel and is attached to the base 30 (see FIG. 2) at a predetermined distance. That is, it is formed to have the same function as the crank arm of the crank mechanism. In the present embodiment, the crank members 24 are arranged at four positions between the base 30 and the carrier holder 22, support the carrier holder 22, and rotate the holder-side shaft 24a about the base-side shaft 24b. This causes the carrier holder 22 to make a circular motion that does not rotate with respect to the base 30. The holder-side shaft 24a is rotatably inserted into a bearing portion 22c provided on the outer peripheral surface of the carrier holder 22 so as to protrude therefrom, and is mounted on the shaft. Thereby, the carrier 1
Numeral 2 is eccentric M from the axis L of the upper surface plate 14 and the lower surface plate 16 and turns (circular motion that does not rotate). The radius of the revolving circular motion is the same as the distance between the shaft 24a on the holder side and the shaft 24b on the base side (distance of the eccentricity M), and all points of the carrier 12 draw the same small circle locus. Become.

Reference numeral 28 denotes a timing chain,
Each crank member 24 is wound around a sprocket 25 (four in this embodiment) fixed coaxially to a shaft 24 b on the base side of each crank member 24. The timing chain 28 and the four sprockets 25 constitute a synchronizing means for connecting and synchronizing the four base shafts 24b so that the four crank members 24 make a circular motion in synchronization. This synchronizing means has a simple configuration, and allows the carrier 12 to move favorably and stably. As a result, the polishing accuracy can be improved, and the flatness of the wafer can be improved. Incidentally, the synchronizing means is not limited to the present embodiment, and it is a matter of course that a timing belt or a gear may be used. Three
Reference numeral 2 denotes a motor (for example, a gear motor), and reference numeral 34 denotes an output gear fixed to an output shaft. The output gear 34 meshes with a gear 26 fixed coaxially to a shaft 24 b of the crank member 24 on the base side. Thereby, the crank member 2
A rotation driving device is configured to rotate the rotation shaft 4 around a shaft 24b on the base side.

It should be noted that a plurality of motors (for example, electric motors) arranged corresponding to the respective crank members 24 can be used as the rotary drive device. In the case of an electric motor, the plurality of crank members 24 can be synchronously moved by electrically synchronizing, and the carrier 12 can be smoothly moved. In this embodiment, the case where four crank members 24 are provided has been described. However, the present invention is not limited to this, and the carrier holder 22 can be suitably supported if at least three crank members 24 are provided. . Further, by combining linear motions of two orthogonal axes, 2
A moving body of an XY table capable of obtaining a dimensional motion;
If the carrier holder 22 and the carrier holder 22 can be moved integrally, by driving one crank member 24,
The carrier holder 22 can be moved in a circular motion without rotating. That is, the moving body makes a non-rotational movement by being guided by the guides extending in two orthogonal axes of the XY table, and the movement of the moving body is converted into a movement of the carrier holder 22 (a circular movement that does not rotate). It can be suitably used. Also, without using the crank member 24 at all, X
You may make it provide a drive means in the Y table itself.
That is, an X-axis and a Y-axis composed of a combination of a servomotor and a ball screw, or a servomotor and a timing chain, for directly driving the X-axis and Y-axis members, respectively
By using a shaft driving mechanism, the carrier holder 22 integrated with the moving body may be moved (circular movement that does not rotate). In this case, at least two motors are used. By controlling the motors, various two-dimensional motions that do not rotate can be obtained in addition to the turning circular motion. Available to

A lower platen rotating motor 36 is a power unit for rotating the lower platen 16 on its own axis. For example, as in the present embodiment, a geared motor can be used, and its output shaft may be directly connected to the rotation shaft of the lower stool 16. Reference numeral 38 denotes a power means for rotating the upper stool, which rotates the upper stool 14 on its own axis.
Lower platen rotating motor 36 and upper platen rotating power means 38
Can flexibly cope with various polishing specifications as long as the rotation direction and the rotation speed can be freely changed. In this double-side polishing apparatus, the wafer 10 arranged in the through-hole 12a of the carrier 12 is sandwiched between an upper platen 14 and a lower platen 16 as shown in FIG. 2, and the wafer is polished. . At this time, the force for clamping the wafer 10 is mainly generated by the pressing means (see FIGS. 6 and 8) provided on the upper surface plate 14 side. For example, by using air pressure, the maximum pressing force is the weight of the upper platen 14, and the pressing force of the upper platen 14 against the wafer 10 is reduced by increasing the air pressure to reduce the pressing force. May be adjusted. In this airbag system, the pressure can be suitably and easily adjusted by controlling the air pressure. In addition,
In addition to the pressing means, an elevating device 40 for elevating and lowering the upper surface plate 14 is provided on the upper surface plate 14 side, and operates when the wafer 10 is supplied and discharged.

Next, regarding the supply means of the liquid abrasive,
A description will be given based on FIG. 1 and FIG. The upper surface plate 14 has an abrasive supply hole 14b for supplying a slurry (liquid abrasive) to a polishing portion where the polishing surface 14a of the upper surface plate 14 contacts the wafer 10 to polish the wafer 10. Is provided. The holes 14b for supplying the abrasive are provided in the wafer 10
It is sufficient that a liquid abrasive can be sufficiently and uniformly supplied to the polishing section, and it is appropriately provided in such a size as not to adversely affect the polishing, and the form and the number thereof are not particularly limited. In addition, the hole 14b for supplying the abrasive in the present embodiment is
A total of 21 pieces are arranged in a matrix so as to be distributed at equal density on the upper surface plate 14, and each is provided with a small diameter. In addition, the hole 14b for supplying the abrasive in the present embodiment.
Are provided to penetrate the upper surface plate 14 in the up-down direction.
Although not shown, a tube or the like is connected to the upper end of the abrasive supply hole 14b so that the liquid abrasive pumped by a pump or the like is appropriately distributed and supplied. .

Then, the liquid abrasive supplied from the abrasive supply hole 14b is passed through the carrier 12 so that the polishing surface 16a of the lower platen (lower platen 16) comes into contact with the wafer 10 so that the wafer 10 comes into contact therewith. A communication hole 15 for supplying a liquid polishing liquid is provided to a polishing section for polishing the wafer 10. This communication hole 15 may be provided in a suitable form at a position that does not affect the strength of the carrier 12, and the size, shape, or number thereof is not limited. In the embodiment shown in FIG. 3, the center of the carrier 12 and the carrier 1
2 between the adjacent through holes 12a in the circumferential direction,
A plurality of circular communication holes 15 are formed.

According to the carrier 12, the liquid polishing liquid can be suitably supplied to both surfaces of the wafer 10 to be polished, and the polishing can be suitably performed. That is, the communication hole 1, which is a hole formed in the carrier 12,
5, and can sufficiently flow into the back surface of the wafer 10 (the surface in contact with the polishing surface 16a). For this reason, the polishing conditions can be uniformly and suitably maintained, and both surfaces of the wafer 10 can be accurately polished. The liquid polishing liquid supplied onto the polishing surface 16a sequentially overflows from the polishing surface 16a in the outer peripheral direction and is discharged, and is further collected and circulated as appropriate, as in the case of the conventional double-side polishing apparatus. .

Next, an embodiment of the vibration preventing means of the upper stool 14 which is a characteristic configuration of the present invention will be described with reference to FIGS. The vibration preventing means shown in FIG. 6 and FIG.
The plurality of rollers 62 abut against the upper platen 14 and prevent the upper platen 14 from swinging in a direction parallel to the surface of the carrier 12. FIG. 6 is a front view, and FIG.
FIG. Reference numeral 60 denotes a guide roller, and the roller 62 is mounted on the main body 64 so as to be rotatable about an axis parallel to a direction (vertical direction) perpendicular to the surface of the carrier 12. Then, the roller 62 is appropriately moved to the upper surface plate 14.
Upper surface plate 14 on base 30 so as to abut outer periphery 14c of
It is provided in the vicinity. By sandwiching the upper surface plate 14 during the polishing process by the plurality of guide rollers 60, the movement of the upper surface plate 14 in a direction parallel to the surface of the carrier 12 can be restricted, and vibration can be prevented. . In this embodiment, four guide rollers 60 are used, but with at least three guide rollers 60, vibration can be suitably prevented.

Such vibration preventing means is particularly suitable for the upper platen 1.
4 is effective in increasing the size and improving the polishing efficiency.
In the double-side polishing apparatus according to the present invention, since the carrier 12 moves independently between the upper stool 14 and the lower stool 16, the upper stool 14 is parallel to the direction (vertical direction) orthogonal to the surface of the carrier 12. It is suspended so as to be able to rotate around a central axis.
As shown in FIG. 6, in this embodiment, a support mechanism for suspending and supporting the upper stool 14 has a portal frame structure 70 and an axis parallel to the portal frame structure 70 in the vertical direction. It is constituted by a spline shaft 72 and the like provided rotatably about a center.

Reference numeral 73 denotes a rotary drive motor, which rotates the upper platen 14 via a speed reducer 74 and a spline shaft 72. Reference numeral 75 denotes a cylinder device which moves the upper platen 14 up and down (arrow F in FIG. 6) via a spline shaft 72. A fixed plate 76 is fixed to the lower end of the spline shaft 72. Fixed to the fixed plate 76 are lower ends of a plurality of airbags 77 and a plurality of swing bearings 78 for swingably supporting the suspension shaft 79. Reference numeral 80 denotes a movable plate, to which the upper end of the airbag 77 and the upper end of the suspension shaft 79 whose lower end is fixed to the upper platen 14 are fixed. Therefore, when the airbag 77 is pressurized, a force in the direction of lifting the upper platen 14 can be obtained, and the oscillating bearing 78 causes the polished surface of the upper platen 14 to follow the polished surface of the lower platen 16. Can tilt.

In the structure of such a support mechanism, the upper surface plate 1
4 is moved up and down, so that the spline shaft 72 is set to be long. For this reason, the upper surface plate 14 easily vibrates in the horizontal direction. That is, while the upper stool 14 rotates at a fixed position, the carrier 12 performs an eccentric turning motion.
Therefore, the upper platen 14 receives a frictional force of a workpiece such as a wafer that is moved by the carrier 12. The frictional force is a force for swinging the upper platen 14 in the horizontal direction. When the spline shaft 72 is long, the spline shaft 72 is likely to vibrate due to a moment. When the weight of the upper surface plate 14 is increased due to an increase in the size thereof, the natural frequency of the suspended portion including the upper surface plate 14 becomes a low value, and the vibration is more likely to occur. Also,
When the number of revolutions of the upper platen 14 is increased, in the worst case, the upper platen 1
There is a problem that the wafer 4 is resonated and the wafer is broken. On the other hand, according to the vibration preventing means, the vibration can be suitably suppressed. Accordingly, it is possible to suitably cope with an increase in the size of the apparatus, and it is possible to increase the number of rotations while making the upper platen 14 heavier, thereby improving the polishing efficiency.

FIG. 8 shows another embodiment relating to the vibration preventing means of the upper stool 14. A tapered recess 82 is provided at the center of the lower surface of the upper surface plate 14, and a tapered protrusion 84 is projected at the center of the upper surface of the lower surface plate 16. Note that a through hole may be provided in the carrier 12 so that the protrusion 84 penetrates. At the time of polishing, by fitting the concave portion 82 and the convex portion 84 together, it is possible to suitably prevent the center runout (vibration) of the upper stool 14. In addition, when the concave portion 82 and the convex portion 84 are rubbed with each other, a bearing may be interposed so as to be able to rotate smoothly. According to this, vibration can be suitably suppressed with a simple configuration. Note that the vibration preventing means is not limited to the above-described embodiment, and other methods may be used. For example, instead of the roller 62 abutting on the outer peripheral surface of the upper stool 14, a fixing member having a suitable sliding surface may be used. Also, a roller is attached to the upper platen 14 side,
It is also possible to provide a circumferential guide on the side of the base 30 to guide the circumference. Further, a concave portion 82 may be provided on the lower surface plate, and a convex portion 84 may be provided on the upper surface plate.

Next, a description will be given of an embodiment of the eccentric load preventing means of the upper stool 14 with reference to FIG. FIG. 9A is a plan view, and FIG. 9B is a front view. According to the eccentric load preventing means of the present embodiment, an axial center perpendicular to the surface of the carrier and parallel to the vertical direction is provided, the lower end is fixed to the upper surface of the upper stool 14, and the upper stool is suspended. A high-precision, high-rigidity spindle 90 is employed as a rotating shaft that rotates. The spindle 90 has a bearing 92 as a bearing.
Is rotatably mounted on the lifting / lowering main body 94 via the.
The lifting / lowering main body 94 has a built-in driving device for driving the spindle 90 to rotate. In addition, the elevating body 94 is
It is provided so as to be vertically reciprocable by being guided by a guide portion 96 which is integrally provided on the base 30. A conical portion 91 is provided at the lower end of the spindle 90 to increase the mounting rigidity.
, The upper surface plate 14 is fixed.

According to such a spindle 90, the parallelism of the upper platen 14 with respect to the lower platen 16 can always be maintained with high accuracy, so that the processing accuracy of a work such as a wafer can be improved. Can be. That is, the carrier 12
Is rotated and eccentric from the axis of the upper stool 14, so that the upper stool 14 as shown in FIG. The load on the upper platen 14 is not evenly applied to each work. On the other hand, if the high rigidity of the spindle 90 always keeps the parallelism between the polished surfaces of the upper stool 14 and the lower stool 16 with high accuracy, the load pressed against each work can be kept uniform. Polishing with high precision is possible. And loading of work,
When removing or replacing the polished surface with a cloth, the upper platen 1
4. The entire upper platen section 95 including the spindle 90 and the lifting / lowering main body 94 containing the drive device for the spindle 90 may be vertically moved (FIG. 9B, arrow G) or turned by a driving means (not shown). As described above, since the entire upper platen portion 95 is moved up and down, the spindle 90 serving as the rotating shaft can be configured shorter than the spline shaft 72 serving as the rotating shaft shown in FIG.
Therefore, the rigidity of the upper stool 14 can be increased, and the parallelism between the polished surfaces of the upper stool 14 and the lower stool 16 can be suitably maintained. Thereby, the load of the upper stool 14 can be evenly applied to each work, and the polishing accuracy can be improved.

Next, an example of a method of using the double-side polishing apparatus according to the present invention will be described. First, a case will be described in which the upper stool 14 and the lower stool 16 are rotated in the same direction but in opposite directions without moving the carrier 12. That is, as shown in FIG.
4 rotates clockwise, and the lower platen 16 rotates counterclockwise.
In this case, since the frictional forces act in completely opposite directions, the kinetic forces cancel each other out, and theoretically the wafer 10
The polishing is performed on both sides in the stopped state. However, in this case, the peripheral speed of the upper surface plate 14 and the lower surface plate 16 becomes larger toward the outer periphery. Therefore, the wafer 10
Polishing is promoted in a portion farther from the portion corresponding to the axis L of the upper platen 14 and the lower platen 16, so that the wafer 10 is not uniformly polished.

Next, a description will be given of a polishing action by causing the carrier 12 to make a circular motion without rotating by the motion mechanism having the above-described configuration. If only the non-rotating circular motion of the carrier 12 is considered without considering the rotation of the upper stool 14 and the lower stool 16, according to the non-rotating circular motion, at all points of the moving member (carrier 12), The same exercise will be done. This is a kind of oscillating motion in the sense that all points are the same motion, and it can be considered that the trajectory of the oscillating motion is a circle. Therefore, if the wafer 10 is swiveled through the carrier 12 which does not rotate and moves in a circular motion, both surfaces of the wafer 10 are uniformly polished if the action by this motion is limited.

When the rotational movement of the upper and lower stools 14 and 16 and the non-rotating circular movement of the carrier 12 are simultaneously operated, the wafer 10 is held rotatably in the through hole 12a. Therefore, in particular, the upper surface plate 14 and the lower surface plate 16
When the absolute value of the rotation speed of the base plate is different (when the rotation speed of the other base plate is increased with respect to one base plate), the wafer 10 is moved in the rotation direction of the base plate having the higher rotation speed. Go around. That is, the wafer 10 rotates in a predetermined direction. In this way, the rotation of the wafer 10 causes the peripheral speed of the upper and lower stools 14 and 16 to increase toward the outer periphery thereof. However, the influence can be eliminated and the wafer 10 can be uniformly polished. it can. In order to uniformly polish both surfaces of the wafer 10, the upper platen 14 and the lower platen 16 may be alternately rotated so that one of them becomes faster.

Next, another example of the method of using the double-side polishing apparatus according to the present invention will be described. In the above embodiment, a plurality of through holes 12a are provided, and a plurality of workpieces (wafer 1) are provided.
In the present invention, the polishing is performed simultaneously. However, the present invention is not limited to this. For example, the carrier 12 is provided with only one through hole 12a for holding a large work, and the polishing is performed on both sides of the large work. It can also be used as a device.
In addition, as a large-sized work, there is a work such as a rectangular glass plate used for liquid crystal, or a wafer (circular) processed by a single wafer. In this case, the large workpiece is the carrier 1
2 is arranged almost entirely from the center to the vicinity of the periphery. At this time, the polishing is performed mainly by using the circular motion of the carrier 12 that does not rotate, and the rotation speed of the upper stool 14 and the lower stool 16 is reduced to such a degree that uneven polishing does not occur. And it can grind suitably. That is, in the upper stool 14 and the lower stool 16, the polishing action becomes larger toward the outer periphery due to the difference in the peripheral speed.
If the rotation speed is much slower than the non-rotating circular motion of the carrier 12, it is possible to make the polishing operation hardly directly involved. The rotation of the upper platen 14 and the lower platen 16 constantly updates the surface of the platen in contact with the work and improves the polishing action, for example, by supplying a liquid abrasive to the entire surface of the work evenly. Indirectly, it can suitably contribute.

Although the polishing apparatus has been described in the above embodiments, the present invention can of course be suitably applied to a lapping apparatus. As described above, the present invention has been described variously with reference to preferred embodiments. However, the present invention is not limited to the embodiments, and it is needless to say that many modifications can be made without departing from the spirit of the invention. That is.

[0043]

According to the double-side polishing apparatus of the present invention, there is provided an anti-vibration means for contacting the upper platen and preventing the upper platen from swinging in a direction parallel to the surface of the carrier. Therefore, it is possible to suitably cope with an increase in the size of the apparatus, to make the upper platen heavier or to increase the number of revolutions of the upper platen, to maintain a high polishing accuracy and to improve the polishing efficiency. Play.

[Brief description of the drawings]

FIG. 1 is an exploded perspective view of an embodiment of a double-side polishing apparatus according to the present invention.

FIG. 2 is a side sectional view of the embodiment of FIG. 1;

FIG. 3 is a plan view and a cross-sectional view showing the entire carrier and carrier holder of the embodiment of FIG. 1;

FIG. 4 is a cross-sectional view illustrating a main part of a linking means according to the present invention.

FIG. 5 is a plan view and a sectional view showing another embodiment of the connecting means according to the present invention.

FIG. 6 is a front view showing one embodiment of the vibration preventing means of the upper stool according to the present invention.

FIG. 7 is a plan view of the embodiment of FIG. 6;

FIG. 8 is an explanatory view showing another embodiment of the vibration preventing means of the upper stool according to the present invention.

FIG. 9 is an explanatory view showing one embodiment of an uneven load preventing means of the upper stool according to the present invention.

FIG. 10 is a cross-sectional view illustrating a conventional technique.

FIG. 11 is a plan view illustrating the arrangement of carriers according to the related art.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Wafer 12 Carrier 12a Through-hole 12b Hole 14 Upper surface plate 14a Polishing surface 14b Hole for supplying abrasive 15 Communication hole 16 Lower surface plate 16a Polishing surface 20 Carrier turning mechanism 22 Carrier holder 23 Pin 24 Crank member 24a Holder side shaft 24b Base-side shaft 28 Timing chain 30 Base 50 Connecting means 60 Guide roller 62 Roller 70 Portal frame 72 Spline shaft 90 Spindle 92 Bearing 94 Elevating body

Continued on the front page (72) Inventor Tomoki Kanda 1650 Kiyono, Matsushiro-machi, Nagano-shi, Nagano F-term in Fujikoshi Machinery Co., Ltd.

Claims (6)

[Claims] 1. A carrier in which a thin plate is provided with a through hole, and a plate-like work disposed in the through hole of the carrier is sandwiched from above and below and is moved relatively to the work to polish the work. An upper surface plate and a lower surface plate, and a circular motion that does not rotate in a plane parallel to the surface of the carrier, and the wafer held between the upper surface plate and the lower surface plate in the through hole. A double-side polishing apparatus comprising: a carrier rotating mechanism for rotating a workpiece; anda vibration preventing means for contacting the upper surface plate and preventing the upper surface plate from swinging in a direction parallel to the surface of the carrier. A double-side polishing apparatus provided. 2. The double-side polishing apparatus according to claim 1, wherein said vibration preventing means comprises a plurality of guide rollers abutting on an outer periphery of said upper platen. 3. The vibration preventing means comprises a concave portion provided at a central portion of the upper platen and a convex portion provided at a central portion of the lower platen so as to fit into the concave portion. The double-side polishing apparatus according to claim 1, wherein 4. The double-side polishing according to claim 1, wherein the upper and lower lapping plates are driven to rotate around an axis parallel to a direction perpendicular to the surface of the carrier. apparatus. 5. A carrier turning mechanism, comprising: a carrier holder for holding the carrier; a holder-side shaft having an axis parallel to a direction perpendicular to a surface of the carrier and being axially mounted on the carrier holder; And a base-side shaft which is parallel to the holder-side shaft and is attached to the base at a predetermined distance from the base-side shaft, and the holder-side shaft is turned around the base-side shaft. 4. A crank member for rotating the carrier holder so as not to rotate with respect to the base body, and a rotation drive device for rotating the crank member about a shaft on the base side.
Or the double-side polishing apparatus according to 4. 6. A plurality of the crank members are provided, and the plurality of shaft members are connected to each other by a synchronization means such as a timing chain so that the plurality of crank members circularly move synchronously. The double-side polishing apparatus according to claim 5.