JP2000167767A - Wafer polishing device and manufacture of wafer by using it - Google Patents

Abstract

PROBLEM TO BE SOLVED: To adjust the gap between a wafer hold head and polishing pad properly and polish a wafer uniflormly by providing a gap adjust mechanism which can adjust the distance size between the wafer hold head and polishing pad. SOLUTION: A wafer is sucked for the wafer sucking seat provided on a carrier, while the projection length from the second hit together part 22 of an adjust member is adjusted. Thereby, when an upperside instalation plate 19 is lowered by an elevator 18 and the lower surface of the first hit together part 24 is contacted with the gap adjust cap of a gap adjust mechanism 23, the lower surface of the wafer and the lower surface of a retainaer are just contacted with the polishing pad 16. Thus, when the wafer is contacted with the polishing pad, a diaphragm is not bent downward. Thereby, the uniformity of the polished surface of the wafer can be ensured favorably.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wafer polishing apparatus and a wafer manufacturing method using the same, and more particularly to an improvement for improving the uniformity of a polishing amount on a wafer surface.

[0002]

2. Description of the Related Art A wafer polishing apparatus of this type includes a disk-shaped platen having a polishing pad attached to a surface thereof, and a plurality of wafer polishing apparatuses for holding one surface of a wafer to be polished and bringing the other surface of the wafer into contact with the polishing pad. It is widely known to provide a wafer holding head and perform polishing by supplying a slurry containing abrasive grains between a polishing pad and a wafer while relatively moving the wafer holding head and the platen. I have.

As one example, there is disclosed a wafer holding head adopting a floating head structure having an advantage that a contact pressure of a wafer against a polishing pad can be made uniform (US Pat. No. 5,205,0).
No. 82).

As shown in FIG. 5, this wafer holding head includes a hollow head main body 1, a diaphragm 2 stretched horizontally in the head main body 1, and a carrier 3 fixed to the lower surface of the diaphragm 2. The carrier 3 is pressed downward by supplying pressurized air from a pressurized air source 6 through a shaft 5 to an air chamber 4 defined by the diaphragm 2.

[0005] A retainer ring 7 is arranged on the outer periphery of the carrier 3 so that the lower end of the retainer ring 7 projects below the carrier 3, and holds the outer periphery of the wafer attached to the lower surface of the carrier 3 while polishing. Is prevented from being detached from the carrier 3.

[0006] Further, it is said that by surrounding the wafer with a retainer ring 7 and polishing the lower end of the retainer ring 7 at the same height as the lower surface of the wafer, overpolishing at the outer peripheral portion of the wafer can be prevented.

[0007]

In the above-described wafer holding head, the carrier 3 and the retainer ring 7 are supported by the diaphragm 2. Therefore, before polishing, that is, before the wafer attached to the carrier 3 is brought into contact with the polishing pad, the weight of the carrier 3 and the retainer ring 7 acts on the diaphragm 2. In this case, since the diaphragm 2 is generally made of a material having elasticity such as rubber, the diaphragm 2 is deformed downward as shown in FIG. In this state, when polishing is started by bringing the wafer holding head close to the polishing pad,
Since the position of the lower surface of the retainer ring 7 is slightly higher than the position where it should be (the same position as the lower surface of the wafer held by the carrier 3), the distance between the wafer holding head and the polishing pad is appropriate. If not adjusted, only the wafer comes into contact with the polishing pad and only the wafer is polished, or the elastic pressure of the diaphragm 2 causes the polishing pressure of the retainer ring 7 to be smaller than the polishing pressure of the wafer. It will be. In such a case,
The wafer is partially overpolished, and the uniformity of the polishing amount is lost.

As described above, in order to ensure the uniformity of the polishing amount of the wafer, it is necessary to perform the polishing while appropriately maintaining the distance between the wafer holding head and the polishing pad. Conventionally, the adjustment of the distance between the wafer holding head and the polishing pad has been usually performed visually. As a result, the probability of producing a wafer lacking in the uniformity of the polishing amount has been high.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and has as its object to improve the uniformity of the polishing amount of a wafer by appropriately adjusting the distance between a wafer holding head and a polishing pad. I do.

[0010]

In order to solve the above problems, the present invention employs the following means. That is, the wafer polishing apparatus according to claim 1 is a platen having a polishing pad attached to a surface thereof, and one or more of two or more holding one surface of a wafer to be polished and bringing the other surface of the wafer into contact with the polishing pad. A wafer polishing apparatus comprising a wafer holding head, and polishing the other surface of the wafer with the polishing pad by the relative movement of the wafer holding head and the platen, wherein the wafer holding head side and the polishing pad side It is characterized in that it is provided with an interval adjusting mechanism that is provided between the wafer holding head and the polishing pad and that can adjust the distance between the wafer holding head and the polishing pad.

According to a second aspect of the present invention, there is provided the wafer polishing apparatus according to the first aspect, wherein the wafer holding head includes a disc-shaped carrier for holding the one surface of the wafer to be polished. A retainer ring concentrically disposed on the outer periphery of the carrier, wherein the retainer ring is displaceable in the head axis direction, and a lower surface thereof is configured to contact the polishing pad during polishing. It is characterized by.

A wafer polishing apparatus according to a third aspect of the present invention is the wafer polishing apparatus according to the first or second aspect, wherein a first butting portion provided on the wafer holding head side and protruding in a head axis direction; A second butting portion provided on the polishing pad side and protruding in the head axis direction and arranged so as to face the first butting portion while being opposed to each other, and the gap adjusting mechanism is It is characterized in that it is provided at one end of the first and second butting portions and abuts on the other during the polishing.

According to a fourth aspect of the present invention, in the wafer polishing apparatus according to the third aspect, the gap adjusting mechanism is screwed to the one of the first and second butting portions. And the length of the protrusion from one side is adjustable.

A wafer polishing apparatus according to a fifth aspect is the wafer polishing apparatus according to the third or fourth aspect, wherein the one end of the first and second butting portions is provided at a tip of the gap adjusting mechanism. The distance adjusting cap which can adjust the protruding length from is provided detachably.

According to a sixth aspect of the present invention, there is provided a wafer manufacturing method using a wafer polishing apparatus, wherein a platen having a polishing pad adhered to a surface thereof, and one surface of a wafer to be polished is held while holding the other surface of the wafer on the polishing pad. A polishing step of polishing the other surface of the wafer with the polishing pad by relatively moving the wafer holding head and the platen using a wafer polishing apparatus having one or two or more wafer holding heads that make contact with the wafer holding head. In the method for manufacturing a wafer, the wafer holding head side of the wafer polishing apparatus is provided with a first butting portion projecting in the head axis direction, while the wafer polishing head is projected in the head axis direction on the polishing pad side. A second butting portion is provided opposite to the first butting portion, and further, the first and second A gap adjusting mechanism is provided at one end of the abutting portion, and when performing the polishing, the wafer holding head is held in advance with the wafer held by the wafer holding head and the polishing pad is , An interval adjustment mechanism provided at one end of the first and second butting portions is brought into contact with the other end.

A wafer manufacturing method using the wafer polishing apparatus according to claim 7 is a wafer manufacturing method using the wafer polishing apparatus according to claim 6, wherein
When the polishing pad is worn, by adjusting the protruding length from the one end of the first and second butting portions of the interval adjusting mechanism, the polishing pad and the polishing pad during the polishing. It is characterized in that the distance from the wafer holding head is adjusted.

[0017]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a schematic configuration of a wafer polishing apparatus 11 according to an embodiment of the present invention. In the drawing, what is indicated by the reference numeral 13 is a base of the wafer polishing apparatus 11, and a disk-shaped platen 14 is horizontally arranged at the center of the base 13.

The platen 14 is rotated about an axis by a platen drive mechanism 15 provided in the base 13, and a polishing pad 16 is adhered to the entire upper surface thereof. I have.

Further, columns 17,... Are provided on the sides of the base 13, and these columns 17,.
The upper mounting plate 19 is mounted via the base 8. The upper mounting plate 19 is configured to support a carousel drive mechanism 20, and a carousel 21 is provided below the carousel drive mechanism 20.

The lifting device 18 has a function of raising and lowering the upper mounting plate 19 and the carousel driving mechanism 20 and the carousel 21 supported by the upper mounting plate 19 along the columns 17,. The carousel drive mechanism 20 has a function of rotating the carousel 21 around an axis.

Also, from the base 13, second butting portions 22,... Are arranged so as to protrude upward. At the upper ends 22a,... Of the second butting portions 22, an interval adjusting mechanism 23 is provided. On the other hand, above the second butting portion 22, the first butting portion 24 is arranged to face. The first butting portion 24 is configured to be fixed to the upper mounting plate 19 and protrude downward from the upper mounting plate 19.

Further, on the lower surface of the carousel 21, a total of six wafer holding heads 25 facing the platen 14,
... are provided. The wafer holding heads 25,.
As shown in FIG. 2, at the same distance from the center of the carousel 21, they are arranged at intervals of 60 ° around the central axis of the carousel 21. The mechanism 20 allows the planetary rotation.

FIG. 3 is a diagram showing details of the configuration of the wafer holding head 25. The wafer holding head 25 has a hollow head main body 28 whose axis is vertically arranged and whose lower end is open, a diaphragm 29 stretched inside the head main body 28, and a disc-shaped fixed to the lower surface of the diaphragm 29. The configuration includes a carrier 30 and an annular retainer ring 32 concentrically arranged on the outer periphery of the carrier 30.

Of these, the head body 28 is composed of a disk-shaped top plate 34 and a cylindrical peripheral wall 35 fixed to the outer periphery of the top plate 34. The shaft 36 is coaxially fixed to the shaft 36. A horizontal step portion 35A is formed on the inner peripheral wall of the peripheral wall portion 35, on which an outer peripheral portion of a disk-shaped diaphragm 29 is placed and fixed with a plurality of screws by a fixing ring 38. The diaphragm 29 is formed of an elastic material such as various rubbers. Further, at the lower end portion of the inner peripheral wall of the peripheral wall portion 35,
A support portion 39 protruding radially inward is formed over the entire circumference.

The carrier 30 is formed of a material having high rigidity such as ceramic and has a constant thickness, and does not deform elastically. In addition, the carrier 30 includes the diaphragm 2.
9 is fixed by a plurality of bolts to a fixing ring 40 arranged coaxially on the upper surface.

The carrier 30 is provided with a suction hole 41 connected to a suction means such as a vacuum pump (not shown) so that the wafer W can be suction-fixed to the lower surface of the carrier 30 during polishing. Has become. Further, the wafer W is attached to the lower surface of the carrier 30 via a circular wafer attachment sheet S. The wafer suction sheet S is formed of, for example, a water-absorbing material, and absorbs a wafer by surface tension when absorbing moisture.

On the other hand, the retainer ring 32 has an upper end surface and a lower end surface formed in a horizontal and flat annular shape. Also,
The retainer ring 32 is concentrically arranged with a slight gap between the retainer ring 32 and the outer peripheral surface of the carrier 30, and is vertically displaceable independently of the carrier 30. further,
A support portion 32a projecting outward in the radial direction is formed on an upper portion of an outer peripheral surface of the retainer ring 32. When the wafer holding head 25 is pulled up, the support portion 32a is formed at a lower end of the peripheral wall portion 35. Is supported by the supporting portion 39.

The upper end of the retainer ring 32 is in contact with the lower surface of the diaphragm 29 and is fixed with a plurality of screws to a fixing ring 42 disposed on the upper surface of the diaphragm 29 at a position facing the retainer ring 32. .

FIG. 4 shows the details of the configuration of the interval adjusting mechanism 23. As shown in FIG. 4, the interval adjusting mechanism 23 includes:
A fixing hole 44 provided at an upper end 22 a of the second butting portion 22, and an adjusting member 4 having a lower end fixed in the fixing hole 44.
5 and a gap adjusting cap 46 provided at the tip of the adjusting member 45. The adjusting member 45
It is a male screw and can be screwed with a female screw cut on the inner peripheral surface 44a of the fixing hole 44. In addition, since such a screw-in type is adopted, the adjusting member 45 is rotated so that the upper end 22 of the second butting portion 22 of the adjusting member 45 is rotated.
It is possible to adjust the protruding length from a. The spacing adjustment cap 46 is configured to be fitted to the protrusion 45 a at the upper end of the adjustment member 45 and to be attachable to and detachable from the adjustment member 45.

Next, a description will be given of a wafer polishing method (wafer manufacturing method) using the wafer polishing apparatus 11 configured as described above. For this, first, the wafer W is sucked to the wafer suction sheet S provided on the carrier 30, and the length of the adjustment member 45 projecting from the second butting portion 22 is adjusted. This allows
When the upper mounting plate 19 is lowered by the elevating device 18 to bring the lower surface of the first butting portion 24 into contact with the gap adjusting cap 46, the lower surface of the wafer W and the lower surface of the retainer ring 32 are just polished by a polishing pad. 16. By doing so, when the wafer W is brought into contact with the polishing pad, the diaphragm 29
Bend down.

After the position of the adjusting member 45 has been adjusted in advance, the upper mounting plate 19 is once raised, and the platen 14 and the carousel 21 are moved using the platen driving mechanism 15 and the carousel driving mechanism 20. Then, the wafer holding head 25 is planetarily rotated with respect to the platen 14. Further, the head driving mechanism is driven to rotate the wafer holding head 25, and the upper mounting plate 19 is lowered again until the first butting portion 24 and the gap adjusting cap 46 contact each other. As a result, the wafer W comes into contact with the polishing pad 16 and wafer polishing is started.

When such wafer polishing is repeatedly performed, the polishing pad 16 is worn, and when the first and second butted portions 24 and 22 are brought into contact with each other, the diaphragm 29 is bent downward. In this case, by replacing the gap adjusting cap 46 with one having an appropriate size, the positions of the diaphragm 29, the wafer W, and the retainer ring 32 during polishing are appropriately maintained. .

As described above, the above-described wafer polishing apparatus 1
1 is that the spacing between the wafer holding head 25 and the polishing pad 16 during polishing can be made appropriate by the spacing adjusting mechanism 23, so that the uniformity of the polished surface of the wafer W is smaller than in the past. Can be better ensured. The features of such a wafer polishing apparatus 11 are as follows.
In particular, the wafer holding head is suitable when the carrier 30 and the retainer ring 32 are a wafer holding head having a floating head structure supported by the diaphragm 29 as in the present embodiment. By preventing downward bending, partial overpolishing of the wafer can be prevented.

Further, in the above-described wafer polishing apparatus 11, the gap adjusting mechanism 23 is provided on the upper end 22a of the second butting portion 22 provided on the base 13, and the gap adjusting mechanism 23 is used for polishing. Since it has a simple configuration in which it comes into contact with the first butting portion 24 which is located in abutment with the second butting portion 22, the wafer holding head 25 and the polishing pad 16 can be easily formed.
Can be adjusted.

Further, in the above-described wafer polishing apparatus 11, the adjusting member 45 of the interval adjusting mechanism 23 is screwed into the fixing hole 44 provided at the upper end 22a of the second butting portion 22. Therefore, the interval adjusting mechanism 23
The protrusion length from the second butting portion 22 can be easily adjusted, thereby enabling highly accurate interval adjustment.

Further, since the gap adjusting cap 46 is replaceable, it is possible to cope with wear of the polishing pad 16.

Further, in the wafer polishing method (wafer manufacturing method) using the wafer polishing apparatus 11, a simple method using the first butting portion 24, the second butting portion 22, and the gap adjusting mechanism 23 is used. With the mechanical configuration, it is possible to realize the adjustment of the distance between the wafer holding head 25 and the polishing pad 16. Therefore, uniformity of wafer polishing can be improved at low cost.

Further, in the wafer polishing method (wafer manufacturing method) using the wafer polishing apparatus 11,
By replacing the gap adjusting cap 46 with one having an appropriate size, the length of the gap adjusting mechanism 23 protruding from the second butted portion 22 was adjusted, thereby coping with wear of the polishing pad 16. It is possible to easily and at a low cost to implement measures against the abrasion of the polishing pad 16.
No troublesome work such as position adjustment and replacement of 6 is required, and workability in wafer manufacturing can be improved.

In the above embodiment, other configurations may be adopted without departing from the spirit of the present invention. For example, in the above embodiment, the interval adjusting mechanism 23 is provided with the upper end 22a of the second butting portion 22.
Provided in the first butting portion 24
It may be attached to the lower surface side of. When the protrusion length of the gap adjusting mechanism 23 can be appropriately adjusted only by the adjusting member 45, the gap adjusting cap 46 can be omitted.

[0040]

As described above, in the wafer polishing apparatus according to the first aspect, the distance between the wafer holding head and the polishing pad during polishing can be made appropriate by the gap adjusting mechanism. Therefore, the uniformity of the polished surface of the wafer can be more preferably ensured as compared with the related art. In the case where the carrier and the retainer ring are structured to be supported by the diaphragm in the wafer holding head as in claim 2, partial downward polishing of the wafer is prevented by preventing the downward bending of the diaphragm. Can be prevented.

In the wafer polishing apparatus according to the third aspect, the first butting portion provided on the wafer holding head side and the second butting portion provided on the polishing pad side are brought into a state of being butted. In addition, since an interval adjusting mechanism is provided at one end of the first and second butting portions, the interval between the wafer holding head and the polishing pad can be easily adjusted with a simple configuration. it can. In this case, as in claim 4,
If the interval adjusting mechanism is configured to be screwed to one of the first and second butting portions, and the length of the interval adjusting mechanism protruding from the one can be easily adjusted, high accuracy is achieved. Interval adjustment is possible. Further, if a detachable gap adjusting cap is provided at the tip of the gap adjusting mechanism as described in claim 5, by exchanging the gap adjusting cap, the polishing of the wafer holding head due to abrasion of the polishing pad or the like can be achieved. It is possible to easily cope with a change in the distance from the pad.

According to a sixth aspect of the present invention, in the polishing step, the wafer holding head has a simple mechanical configuration using the first butting portion, the second butting portion, and the gap adjusting mechanism. Adjustment of the distance between the polishing pad and the polishing pad can be realized, and the uniformity of wafer polishing can be improved at low cost.

Further, in the wafer manufacturing method according to the seventh aspect, the length of the interval adjusting mechanism protruding from the second butting portion is adjusted to cope with the wear of the polishing pad. In addition, it is possible to realize a countermeasure against abrasion of the polishing pad, and even if the polishing pad is worn out, troublesome work such as adjusting the position of the polishing pad or replacing the polishing pad is not required, thereby improving workability in wafer manufacturing. be able to.

[Brief description of the drawings]

FIG. 1 is a front view of a wafer polishing apparatus schematically showing an embodiment of the present invention.

FIG. 2 is a plan view showing an arrangement state of a wafer holding head and a carousel in the wafer polishing apparatus shown in FIG.

3 is an elevational sectional view showing details of a configuration of a wafer holding head of the wafer polishing apparatus shown in FIG. 1;

FIG. 4 is an elevational sectional view showing details of a configuration of a gap adjusting mechanism in the wafer polishing apparatus shown in FIG. 1;

FIG. 5 is an elevational sectional view of a wafer holding head showing a conventional technique of the present invention.

FIG. 6 is an elevational sectional view showing a state where the diaphragm in the wafer holding head shown in FIG. 5 is deformed by the retainer ring and the carrier's own weight.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 Wafer polishing apparatus 14 Platen 16 Polishing pad 21 Carousel 22 Second butting part 22a Upper end 23 Interval adjusting mechanism 24 First butting part 25 Wafer holding head 29 Diaphragm 30 Carrier 32 Retainer ring 46 Interval adjusting cap

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Jiro Kajiwara 1-297 Kitabukurocho, Omiya City, Saitama Prefecture Inside Mitsubishi Materials Research Institute (72) Inventor Masato Komazaki 1-297 Kitabukurocho, Omiya City, Saitama Mitsubishi Materials F-term in Reference Laboratory Co., Ltd. (reference) 3C058 AA07 AA16 AB03 AB04 AB06 AB08 AC04 DA02 DA09 DA17

Claims (7)

[Claims] 1. A platen having a polishing pad affixed to a surface thereof, and one or more wafer holding heads for holding one surface of a wafer to be polished and bringing the other surface of the wafer into contact with the polishing pad. A wafer polishing apparatus for polishing the other surface of the wafer with the polishing pad by a relative movement between the wafer holding head and the platen, provided between the wafer holding head side and the polishing pad side, A wafer polishing apparatus, comprising: a distance adjusting mechanism capable of adjusting a distance dimension between a wafer holding head and a polishing pad. 2. The wafer polishing apparatus according to claim 1, wherein the wafer holding head includes a disk-shaped carrier for holding the one surface of a wafer to be polished on a diaphragm provided on a head body; A retainer ring concentrically disposed on the outer periphery of the carrier is fixed, and the retainer ring is displaceable in a head axis direction, and a lower surface thereof is configured to contact the polishing pad during polishing. A wafer polishing apparatus, comprising: 3. The wafer polishing apparatus according to claim 1, wherein a first butting portion provided on the wafer holding head side and protruding in a head axis direction, and a head provided on the polishing pad side. And a second butting portion that protrudes in the axial direction and that is opposed to the first butting portion while being abutted against the first butting portion. A wafer polishing apparatus provided at one end of one of the sections and abutting on the other during the polishing. 4. The wafer polishing apparatus according to claim 3, wherein the gap adjusting mechanism is screwed with respect to the one of the first and second butting portions, and is provided with a screw from the one. A wafer polishing apparatus, wherein a projection length is adjustable. 5. The wafer polishing apparatus according to claim 3, wherein a protrusion length of said first and second butting portions from said one of said first and second butting portions is adjustable at a tip of said gap adjusting mechanism. A wafer polishing apparatus, wherein an interval adjusting cap is provided so as to be detachable. 6. A platen having a polishing pad attached to a surface thereof, and one or more wafer holding heads for holding one surface of a wafer to be polished and for abutting the other surface of the wafer to the polishing pad. Using a wafer polishing device,
A wafer manufacturing method including a polishing step of polishing the other surface of the wafer with the polishing pad by relatively moving the wafer holding head and the platen, wherein the wafer holding head side of the wafer polishing apparatus,
While a first butting portion protruding in the head axis direction is provided, a second butting portion is provided on the polishing pad side, which protrudes in the head axis direction and is arranged to face the first butting portion, Further, an interval adjusting mechanism is provided at one end of the first and second butting portions, and when performing the polishing, in advance, the wafer is held by the wafer holding head, Using a wafer polishing apparatus, wherein the wafer holding head is brought close to the polishing pad, and a gap adjusting mechanism provided at one end of the first and second butting portions is brought into contact with the other. Wafer manufacturing method. 7. A wafer manufacturing method using the wafer polishing apparatus according to claim 6, wherein when the polishing pad is worn by the polishing, the first and second buttings of the gap adjusting mechanism are performed. Adjusting the distance between the polishing pad and the wafer holding head during polishing by adjusting the length of protrusion from the one end of the portion. .