JP2000042912A - Double-side polishing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To supply a liquid abrasive of a sufficient flow rate to the polishing part by forcibly sending the liquid abrasive from an abrasive supply hole arranged in an upper surface plate and/or a lower surface plate. SOLUTION: An abrasive supply hole 16b is arranged in a lower surface plate 16. A forcibly sending supply device 85 for forcibly sending slurry is composed of a slurry storage tank and a slurry sending pump. A communicating passage 86 is composed of a vertical pipe 86a communicating with the hole 16b by passing through into a hollow autorotating shaft 36a, a horizontal pipe 86b communicating the vertical pipe 86a with the sending supply device 85 and a pipe joint. The slurry pressurized to high pressure is sent through this communicating passage 86 to be delivered from the abrasive supply hole 16b. Since the slurry delivered from the abrasive supply hole 16b flows to the outer periphery from the central part by centrifugal force by being received to the polishing surface of the lower surface plate 16 by this abrasive supply means, the slurry can be sufficiently supplied to the whole polishing part.

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. 12 is a plan view for explaining an example of the arrangement of carriers 120 according to the polishing apparatus of 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 formed of a thin flat 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 at the same time relative to the wafer. A polishing machine comprising an upper surface plate and a lower surface plate having a polishing surface for selectively moving and polishing, wherein the carrier moves a circular motion that does not rotate in a plane parallel to the surface of the carrier via a carrier holder. And a carrier rotating mechanism for rotating the wafer held between the upper surface plate and the lower surface plate in the through hole. In addition, the upper surface plate and the lower surface plate are each provided so as to perform a rotation (rotation).

Then, in order to supply a liquid abrasive to a polishing portion for polishing the wafer by bringing the polishing surfaces of the upper and lower platens into contact with each other, as shown in FIG. Slurry) is allowed to fall naturally. Numeral 39 denotes a slurry ring, which is formed in a ring-like groove shape so as to store the slurry pumped up by a liquid abrasive supply device (not shown). 39a is a supply pipe,
The slurry ring 39 is provided as a conduit communicating with the abrasive supply hole 14 b provided on the upper surface plate 14. The slurry naturally falls through the supply pipe 39a, is discharged from the polishing agent supply hole 14b, and is supplied to the polishing section. Reference numeral 72 denotes a spline shaft, which rotates the upper platen 14 and suspends it vertically. Reference numeral 76 denotes a fixing plate 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, which is provided not to be fixed to the spline shaft 72 so as to be vertically movable, has an outer peripheral portion serving as the slurry ring 39, and has an upper end and a lower end of the airbag 77 on the upper surface plate 14. The upper end of the fixed suspension shaft 79 is fixed. Therefore, if the airbag 77 is pressurized, a force in the direction of lifting the upper stool 14 can be obtained, and the pressing load applied to the wafer by the upper stool 14 can be controlled. In addition, by the action of the swing bearing 78, the polished surface of the upper stool 14 can be tilted by following the polished surface of the lower stool 16 (see FIG. 1).

[0009]

However, in the double-side polishing apparatus of the background art, the carrier 12 is mounted on the lower platen 16.
And a liquid abrasive is applied to the upper surface plate 14.
When the abrasive is supplied from the abrasive supply hole 14b, there is a problem that the abrasive in a liquid state accumulates on the upper side of the carrier 12 and does not flow downward, and is not sufficiently supplied to the polishing surface of the lower platen 16. That is, the slurry is leaked from a slight gap between the inner peripheral surface of the through hole holding the work and the outer peripheral surface of the work and supplied to the polishing surface of the lower platen 16, and the supply amount is sufficient. Did not. In contrast, FIG.
Alternatively, as shown in FIG. 3, when the carrier 12 is provided with the communication hole 15 for allowing the slurry to pass, a certain effect was obtained. However, since the distance between each polished surface and the surface of the carrier 12 is very small, it flows only in the easy-to-flow area, and it is difficult to supply a sufficient flow rate of the slurry entirely. In particular, it was difficult to supply the slurry near the center of each platen. Since the slurry is not appropriately supplied to the polishing section, temperature variations occur on the polishing surface of each platen. This is because if the supply flow rate of the slurry is not sufficient, the polishing heat due to the friction between the workpiece and the polishing surface cannot be cooled appropriately. When the temperature variation occurs on the polished surface as described above, the polishing conditions are different for each part of the work, and as a result, the polishing accuracy of the work is reduced.

Accordingly, an object of the present invention is to provide a double-side polishing apparatus provided with a carrier that makes a circular motion that does not rotate, and a polishing section that polishes the work by contacting the work with the polishing surfaces of the upper surface plate and the lower surface plate. Another object of the present invention is to improve the polishing accuracy by enabling a sufficient flow rate of a liquid abrasive to be supplied.

[0011]

To achieve the above object, the present invention has the following arrangement. That is, the present invention
It has a carrier in which a thin plate is provided with a through-hole, and a polishing surface that sandwiches a plate-shaped work arranged in the through-hole of the carrier from above and below and moves relatively to the work to polish the work. An upper platen and a lower platen, and a circular motion that does not rotate on the carrier in a plane parallel to the surface of the carrier, and the wafer held between the upper platen and the lower platen in the through hole. A carrier rotating mechanism for rotating a workpiece, and an abrasive provided on an upper surface plate and / or a lower surface plate for supplying a liquid abrasive to a polishing section for polishing the workpiece by contacting the polishing surface with the workpiece. Abrasive supply means for discharging the liquid abrasive that has been fed under pressure from a supply hole.

In the abrasive supply means, a plurality of abrasive supply holes are provided at different positions in the radial direction of the upper surface plate and / or the lower surface plate, and the plurality of abrasive supply holes are provided. By providing a plurality of paths for supplying the liquid abrasive corresponding to the holes, it is possible to cool the entire polishing surface in a well-balanced manner, and to reduce the polishing accuracy of the polishing surface due to polishing heat. It can be suitably prevented.

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. It has a simple structure, but has a simple structure while holding the carrier holder with a crank member that makes a circular motion that does not rotate the carrier holder with respect to the base, and a drive device that rotates the crank member about an axis on the base side. It is possible to make the carried 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 an embodiment of a basic configuration of a double-side polishing apparatus according to the present invention, and FIG. 2 shows a positional relationship of each configuration when the embodiment of FIG. 1 is operating. FIG. The present embodiment is a double-side polishing apparatus for polishing a silicon wafer 10 which is a plate-shaped work. The carrier 12 has a through-hole 12a formed in a thin flat plate, and is disposed in the through-hole of the carrier 12. An upper surface plate 14 and a lower surface plate 16 for sandwiching the wafer 10 from above and below and moving the wafer 10 relatively to the wafer 10 for polishing are provided. A polishing cloth called a cloth is attached to each surface of the upper stool 14 and the lower stool 16, and the polishing surfaces 14 a and 16 a are formed by the polishing cloth. 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 has a circular shape and is loosely fitted in the circular through hole 12a, and has a size capable of rotating freely in the through hole 12a. 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 or a servo motor), and reference numeral 34 denotes an output gear fixed to an output shaft. The output gear 34 is a shaft 24 on the base side of the crank member 24.
The gear 26 is engaged with a gear 26 fixed coaxially with the gear b. As a result, a rotary driving device that rotates the crank member 24 about the shaft 24b on the base side is configured.

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, a gear motor or a servo motor can be used, and the output shaft of the motor 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. As with the lower platen rotating motor 36, an electric motor or the like that can be used for rotating power may be appropriately used. Lower surface plate rotation motor 3
6 and the upper platen rotating power means 38 can flexibly cope with various polishing specifications as long as the rotating direction and the rotating speed can be freely changed. Further, in this double-side polishing apparatus, the wafer 10 disposed in the through hole 12a of the carrier 12 is
As shown in FIG. 2, the upper platen 14 and the lower platen 16 are sandwiched, and the wafer is polished. At this time, the force for clamping the wafer 10 is mainly generated by the pressing means provided on the upper surface plate 14 side (see FIG. 10). For example,
Utilizing air pressure, the maximum pressure is the weight of the upper surface plate 14, and the wafer 1 of the upper surface plate 14 is operated in an air bag system in which the air pressure is increased to reduce the pressure.
The pressing force to zero may be adjusted. In this airbag system, the pressure can be suitably and easily adjusted by controlling the air pressure. In addition to the pressing means, an elevating device 40 for moving the upper stool 14 up and down is provided on the upper stool 14 side, and operates when the wafer 10 is supplied and ejected.

As shown in FIG. 1, reference numeral 62 denotes a roller, which is an anti-vibration means for abutting against the upper platen 14 and for preventing the upper platen 14 from swinging in a direction parallel to the surface of the carrier 12. This is an example. The roller 62 may be attached to the upper surface plate 14 as appropriate.
The upper surface plate 14 on the base 30 is brought into contact with the outer periphery 14c of
It is rotatably mounted on a guide roller body (not shown) provided in the vicinity. By sandwiching the upper surface plate 14 when the polishing process is performed by the plurality of rollers 62,
The movement of the upper stool 14 in a direction parallel to the surface of the carrier 12 can be restricted to prevent vibration.

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 in FIG. 3, a tube or the like is connected to the upper end of the abrasive supply hole 14b as shown in FIG.
The liquid abrasive pumped by a pump or the like is provided so as to be appropriately distributed and supplied.

Then, the liquid abrasive supplied from the abrasive supply hole 14b is passed through the carrier 12, and the polishing surface 16a of the lower platen (lower platen 16) is brought into contact with the wafer 10 so as to contact the carrier. 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 flow into the back surface of the wafer 10 (the surface in contact with the polishing surface 16a). Therefore, the polishing conditions can be made uniform, and both sides of the wafer 10 can be polished with high precision. In addition, 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 as in the case of the conventional double-side polishing apparatus.
It is further collected and circulated as appropriate.

Next, an embodiment of the abrasive supply means, which is a characteristic configuration of the present invention, will be described with reference to FIGS. FIG. 6 is a cross-sectional view illustrating the abrasive supply means provided on the lower platen. FIG. 7 is a cross-sectional view illustrating the abrasive supply means provided on the upper platen. FIGS. 8 and 9 are explanatory views illustrating abrasive supply means provided on the upper platen and provided with a supply path for a plurality of systems of slurry (liquid abrasive). Note that the same components as those in the above-described embodiment are denoted by the same reference numerals, and description thereof will be omitted.

FIG. 6 shows a polishing table provided on the lower platen 16 for supplying a liquid abrasive (slurry) to a polishing section for polishing the wafer 10 by bringing the polishing surfaces 12a and 14a into contact with the wafer 10. A polishing agent supply means for discharging the slurry fed under pressure from the agent supply hole 16b is shown.
Reference numeral 85 denotes a pressure feeder for feeding the slurry under pressure, which is composed of a tank for storing the slurry, a pump for feeding the slurry, and the like. Reference numeral 86 denotes a communication path, which is an upper and lower pipe 86a vertically arranged on the axis of the hollow rotation shaft 36a for rotating the lower platen 16 and communicating with the abrasive supply hole 16b, and the upper and lower pipes 86a and the pressure feeder 85. Horizontal pipe 8 communicating with
6b, a pipe joint, and the like. The slurry pressurized to a high pressure is sent through the communication passage 86 and discharged from the abrasive supply hole 16b. According to this abrasive supply means, a sufficient flow rate of slurry can be forcibly and suitably supplied (pressurized) to the polishing section.
The surface temperature of the polishing surfaces 12a and 14a can be made uniform by suitably cooling the surface 14a. The slurry discharged from the abrasive supply hole 16b provided at the center of the lower platen 16 is:
It is received on the polishing surface 16a of the lower stool 16 and flows from the center to the outer periphery by centrifugal force. For this reason, although the number of holes 16b for supplying the abrasive is one, a sufficient amount of slurry can be suitably supplied to the entire polishing section.

In FIG. 7, an upper platen 14 is provided to supply a liquid abrasive (slurry) to a polishing section for polishing the wafer 10 by bringing the polishing surfaces 12a and 14a into contact with the wafer 10. An abrasive supply means for discharging the slurry fed under pressure from the abrasive supply hole 14b is shown.
Reference numeral 85a denotes a pressure feeding supply device for feeding the slurry under pressure, which includes a tank for storing the slurry, a pump for feeding the slurry, and the like. Reference numeral 87 denotes a communication passage, which is vertically arranged on the axis of a hollow rotation shaft 38a for rotating the upper platen 14, and communicates with a pressure feeder 85a. It is composed of a branch pipe 87b communicating with the supply hole 14b, a pipe joint, and the like. The slurry pressurized to a high pressure is sent through the communication passage 87 and discharged from the abrasive supply hole 14b. According to this abrasive supply means, a sufficient flow rate of slurry can be forcibly and suitably supplied (pressurized) to the polishing unit, and in particular, the polishing surfaces 12a and 14a are suitably cooled and the polishing surface 12a is cooled.
a, the surface temperature of 14a can be made uniform. It is needless to say that the abrasive supply means shown in FIG. 6 and the abrasive supply means shown in FIG.
a, the surface temperature of 14a can be more preferably made uniform.

Next, based on a comparative experiment, the operation and effect in the case where a sufficient flow rate of the slurry can be supplied to the polishing section by pumping the slurry as in the embodiment of FIGS. 6 and 7 will be described. explain. When the slurry of 0.5 liter per minute was supplied to the polishing unit, and when the slurry of 3.0 liter per minute was supplied to the polishing unit,
One polishing step of the wafer was 60 minutes, and five polishing steps (300 minutes in total) were continuously performed. The conditions other than the flow rate of the slurry are the same. Eight measurement points are set at different positions in the radial direction of the surface (polishing surface) of the lower stool 16, and the surface temperature of each measurement point is set to 60 minutes including the start of the polishing process (0 minute). Was measured. Then, the average value of the surface temperature at each measurement and the variation of the surface temperature between the measurement points at each measurement were compared. In addition, for each wafer processed in each polishing step, eight measurement points are set at different positions in the radial direction of the wafer, and the thickness of each measurement point is measured to determine the thickness of the wafer. The variation was compared.

The experimental results will be described below. First, the surface temperature of the lower platen 16 will be described. When 0.5 liter per minute was supplied, the average temperature was about 22 degrees Celsius at the start of polishing (0 minutes), but increased to about 34 degrees Celsius after 300 minutes, About 12 degrees of opening occurred in Celsius. The maximum temperature variation between the measurement points at each measurement was about 5 degrees Celsius and about 3 degrees Celsius on average. In contrast, 3.0 per minute
When liters are supplied, the average temperature is almost constant at about 28 degrees Celsius (difference within 1 degree) throughout the entire measurement, and the temperature variation between each measurement point at each measurement is the highest. It was about 1.5 degrees Celsius and less than 1 degree on average.

Next, the variation in the thickness of the polished wafer will be described. When 0.5 liter per minute was supplied, there was a variation of 2.2 μm at the maximum and 1.3 μm on average. On the other hand, when 3.0 liters per minute is supplied, the maximum is 0.8 μm and the average is 0.6 μm.
m. In other words, the polishing accuracy was more than doubled as compared with the case of 0.5 liter per minute. As described above, when 3.0 liter per minute was supplied, the polished surface could be maintained at a uniform temperature, and the wafer could be flattened with extremely high precision. That is, by increasing the amount of slurry supplied,
The surface temperature of the polishing surfaces 14a and 16a (temperature of the polishing cloth surface) can be prevented from rising, and the polishing surface 1
Variations in the surface temperatures of 4a and 16a can be reduced. By maintaining uniform polishing conditions relating to the surface temperatures of the polishing surfaces 14a and 16a, the polishing accuracy of the wafer can be significantly improved.

Next, with reference to FIGS. 8 and 9, a description will be given of an abrasive supply means having a plurality of slurry supply paths. In both embodiments, the holes 14b for supplying the abrasive are used.
Are provided at a plurality of different positions in the radial direction of the upper platen 14, and correspond to the plurality of holes 14b for supplying the abrasive,
A plurality of paths for supplying the slurry are provided.
In the embodiment shown in FIG. 8, a plurality of pressure feeding devices 88a, 88
b, 88c, through a plurality of supply paths 98a, 98b, 98c composed of a distributor 89 provided on the rotating shaft and a pipe passing through the rotating shaft, etc. From the nozzle. The distributor 89 is a known technique for supplying a fluid in a rotating member while sealing the fluid. Reference numeral 97 denotes a sequencer, which receives signals from temperature sensors 99a, 99b, and 99c disposed near the respective abrasive supply holes 14b,
A command signal is sent to a plurality of pressure feed devices 88a, 88b, 88c. Thereby, each of the supply paths 98a, 98b, 98
Feedback control is performed on the flow rate and the like of the slurry discharged from each of the polishing agent supply holes 14b through c to cool the polishing surfaces 14a and 16a and maintain the surface temperature thereof constant.

That is, each of the pressure feeding / supplying devices 88a, 88
Each of b and 88c is provided with a tank for adjusting the temperature of the slurry, a pump capable of changing the flow rate of the slurry to be pumped, and the like. Therefore, each of the pressure feeding and supplying devices 88a, 8
8b and 88c are controlled by the sequencer 97 to increase the amount of slurry supplied to the polishing agent supply holes 14b in the vicinity of the polishing surfaces 14a and 16a where a large amount of polishing heat is generated. Can supply slurry. Thereby, cooling can be suitably performed in accordance with the heating condition of each portion of the polishing surfaces 14a and 16a, the surface temperature can be made uniform over the entire surface, and the polishing accuracy of the wafer can be significantly improved.

In this embodiment shown in FIG. 9, a plurality of automatic flow control valves 83a, 83b are branched from the pressure feeder 88d.
3b, 83c, a distributor 89, and a plurality of supply paths 98a, 9 including pipes passing through the rotation shaft.
The slurry is discharged from each of the abrasive supply holes 14b through 8b and 98c. Reference numeral 97 denotes a sequencer, which sends a command signal to a plurality of automatic flow control valves 83a, 83b, 83c in response to a signal from a temperature sensor 99a, 99b, 99c disposed near each abrasive supply hole 14b. .
Thus, the flow rate of the slurry flowing through each supply path 98a, 98b, 98c and discharged from each abrasive supply hole 14b is controlled by a plurality of automatic flow control valves 83a, 83b, 83c.
To maintain the surface temperature of the polished surfaces 14a and 16a constant.

As described above, each of the automatic flow control valves 83a, 83
By controlling the 3b and 83c with the sequencer 97, if the supply amount of the slurry is increased to the polishing agent supply hole 14b near the portion of the polishing surface 14a or 16a where a large amount of polishing heat is generated, the polishing surface 14a, 16a can be suitably cooled in accordance with the heating condition of each part, and its surface temperature can be made uniform over the entire surface. Therefore, the polishing accuracy of the wafer can be significantly improved. The sequencer 97, a temperature sensor,
The exchange of signals with the pressure feeder and the automatic flow control valve may be performed by wiring as in this embodiment, or may be performed wirelessly. The pressure at which the slurry is pumped may be about ² to 3 kg / cm ² , but may be higher. Further, in the above-described embodiment, the case where a plurality of slurry supply paths are provided in the upper surface plate 14 has been described. However, the present invention is not limited to this, and the lower surface plate 1
6 can also be provided.

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 structure. 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 motion of the upper and lower stools 14 and 16 and the circular motion of the carrier 12 that do not rotate are simultaneously activated, the wafer 10 is rotatably held 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 above embodiment has been described with reference to a polishing apparatus, 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.

[0047]

According to the double-side polishing apparatus of the present invention, the polishing agent supply means supplies the liquid polishing agent to the polishing section for polishing the work by bringing the polishing surfaces of the upper and lower platens into contact with each other. In order to discharge the abrasive in a liquid state, the abrasive is supplied from the abrasive supply holes provided in the upper and / or lower stool.
According to this, in a double-side polishing apparatus having a carrier that makes a circular motion that does not rotate, it is possible to supply a sufficient flow rate of a liquid abrasive to the polishing section, and to make the surface temperature of the polishing surface uniform. Since the polishing accuracy can be maintained, the polishing accuracy can be improved.

[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 cross-sectional view illustrating an embodiment of an abrasive supply unit according to the present invention.

FIG. 7 is a cross-sectional view illustrating another embodiment of the abrasive supply means according to the present invention.

FIG. 8 is an explanatory diagram illustrating an embodiment of an abrasive supply unit having a plurality of paths.

FIG. 9 is an explanatory diagram illustrating another embodiment of the abrasive supply means having a plurality of paths.

FIG. 10 is a cross-sectional view illustrating an abrasive supply means of the background art.

FIG. 11 is a cross-sectional view illustrating a conventional technique.

FIG. 12 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 swivel mechanism 22 Carrier holder 23 Pin 24 Crank member 24a Holder side shaft 24b Substrate side shaft 28 Timing chain 30 Substrate 32 Motor 40 Upper platen lifting and lowering device 85 Pressure feed supply means 85a Pressure feed supply means 86 Communication path 87 Communication path 88a, 88b, 88c Pressure feed supply means 88d Pressure feed supply means 89 Distributor 97 Sequencer 98a , 98b, 98c Supply path 99a, 99b, 99c Temperature sensor

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Tomoki Kanda 1650 Kiyono, Matsushiro-machi, Nagano-shi, Nagano F-term (reference) in Fujikoshi Machinery Co., Ltd. 3C058 AA07 AA16 AB04 AB06 AC04 CB01 DA06 DA18

Claims (5)

[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 having a polished surface to be rotated, and the carrier is caused to make a circular motion that does not rotate in a plane parallel to the surface of the carrier, and is held between the upper surface plate and the lower surface plate in the through hole. A carrier rotating mechanism for rotating the work, and an upper surface plate and / or a lower surface plate for supplying a liquid abrasive to a polishing section for polishing the work by contacting the polishing surface with the work. A polishing agent supply means for discharging the pressure-fed liquid abrasive from a polishing agent supply hole provided in the polishing apparatus. 2. The abrasive supply means, wherein a plurality of holes for supplying the abrasive are provided at different positions in a radial direction of an upper surface plate and / or a lower surface plate, and the plurality of holes for supplying the abrasive are provided. 2. The double-side polishing apparatus according to claim 1, wherein a plurality of paths for supplying the liquid abrasive are provided corresponding to the holes. 3. The double-side polishing apparatus according to claim 1, wherein the upper surface plate and the lower surface plate are driven to rotate around an axis parallel to a direction perpendicular to the surface of the carrier. 4. The carrier swiveling mechanism comprises: 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 in a circular motion without rotating with respect to the base, and a driving device for rotating the crank member about a shaft on the base side. Double-side polishing machine. 5. The apparatus according to claim 1, wherein a plurality of the crank members are provided, and the shafts on the base side are connected to each other by a synchronization means such as a timing chain so that the plurality of crank members make a circular motion in synchronization. The double-side polishing apparatus according to claim 4.