JPH10315121A - Surface grinding device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the flatness of a work after it is ground, by preventing air from entering when mounting an abrasive cloth and a backing pad on the turntable and the holding plate of a surface grinding device. SOLUTION: A surface grinding device comprises a turntable 1, a grinding head, an abrasive supply nozzle, and a dressing head. An abrasive cloth is bonded to the top surface of the turntable 1. The grinding head comprises a rotating and pressing mechanism, a shaft and a holding plate 7. A backing pad is bonded to the underside of the holding plate 7. A wafer is sucked by the backing pad to be set on the grinding head. Further, the turntable 1 has grid-shaped grooves 21 on the whole surface and the holding plate 7 also has grid-shaped grooves 31 on the whole surface.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flat surface polishing apparatus used for flattening the surface of a plate-like material to be polished such as a silicon wafer, and more particularly to improving the flatness of the material to be polished. For improvement.

[0002]

2. Description of the Related Art FIG. 4 shows an outline of a conventional planar polishing apparatus. The planar polishing apparatus includes a turntable 1, a polishing head 4, an abrasive supply nozzle 9, a dressing head 11, and the like. The turntable 1 has a polishing cloth 3 adhered to the upper surface thereof, and is driven by a rotation drive mechanism 2 disposed below the polishing cloth 3. The polishing head 4 includes a rotating and pressing mechanism 5, a shaft 6 extending downward from the rotating and pressing mechanism 5,
It is composed of a holding plate 7 fixed to the lower end of the shaft 6 and the like. A backing pad 8 is adhered to the lower surface of the holding plate 7, and a wafer 10 to be polished is attracted to the backing pad 8 and set on the polishing head 4. The dressing head 11 is used for removing clogging of the polishing pad.

The polishing operation of the wafer 10 is performed as follows. The polishing pad 3 is adhered to the turntable 1, and the wafer 10 is sucked to the holding plate 7 via the backing pad 8. Next, the turntable 1 is rotated, and the abrasive is supplied from the abrasive supply nozzle 9 to the surface of the polishing cloth 3. Finally, the rotation / pressing mechanism 5 is activated to rotate the holding plate 7 and press the wafer 10 against the surface of the polishing pad 3.

In the above-described planar polishing apparatus, the flatness of the polishing pad 3 is transferred to the surface of the wafer 10 without any change.
The dressing is performed using the dressing head 11. Further, the backing pad 8, for the purpose of polishing the wafer 10 on the surface reference, the Young's modulus of the polishing pad 10 (e.g., 29kgf / cm ²⁾ compared to the much smaller Young's modulus (e.g., 0.04kgf / cm ² )have. The backing pad 8 is made of urethane,
It is manufactured with high dimensional accuracy with a thickness variation of 3 μm or less.

When attaching the polishing pad 3 and the backing pad 8 to the turntable 1 and the holding plate 7, respectively, an organic adhesive is used. At the time of bonding the polishing pad 3 or the backing pad 8, it is necessary to prevent the entrapment of air, so that the worker must be extremely careful. However, even with careful work,
It is not easy to completely eliminate minute bubbles. Even if pressure is applied from the surface side of the polishing pad 3 or the backing pad 8, the air entrapped in this manner does not have a sufficient path for escaping the air, so that a part of the air remains, Form protrusions. These small protrusions are one of the factors that lower the flatness of the polished wafer.

[0006]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide a flat-surface polishing apparatus using a polishing cloth or a backing pad.
It is an object of the present invention to provide a structure capable of preventing air from being entrained when attached to a turntable or a holding plate, thereby improving the flatness of a material to be polished after polishing.

[0007]

According to the present invention, there is provided a planar polishing apparatus comprising: a turntable having an upper surface to which a polishing cloth is adhered; a backing pad disposed above the turntable opposite to the turntable and adhered to the lower surface. A polishing head for adsorbing and holding a flat plate-like material to be polished, and while supplying the polishing agent onto the polishing cloth, rotating the material to be polished with the polishing head and pressing against the polishing cloth to perform polishing. In the polishing apparatus, a groove for eliminating air bubbles is formed on the surface of the turntable.

Further, the planar polishing apparatus of the present invention comprises a turntable having an upper surface to which a polishing cloth is adhered, and a flat backing pad disposed above the turntable opposite to the turntable and adhered to the lower surface. A polishing head that comprises a polishing head that adsorbs and holds the material to be polished, while supplying the polishing agent onto the polishing cloth, while rotating the material to be polished with the polishing head and pressing against the polishing cloth to perform polishing,
A groove for eliminating air bubbles is formed on the surface of the polishing head.

According to the planar polishing apparatus of the present invention, since a groove is formed on the surface of the turntable or the polishing head so that air bubbles are eliminated through the groove, the polishing cloth or the backing pad can be used. , Respectively, when gluing to the surface of the turntable or polishing head,
Bubbles trapped on the back side of the polishing pad or the backing pad can be relatively easily removed through the groove by applying pressure from the front side of the polishing pad or the backing pad. Therefore, unlike the conventional apparatus, no small protrusions are formed, and the flatness of the polishing pad or the backing pad is ensured. As a result, it is effective in improving the flatness of the wafer polished using the planar polishing apparatus.

[0010]

FIG. 1 shows an outline of a planar polishing apparatus according to the present invention. The planar polishing apparatus includes a turntable 1, a polishing head 4, an abrasive supply nozzle 9, a dressing head 11, and the like. Turntable 1
The polishing pad 3 is adhered to the upper surface thereof, and is driven by the rotary drive mechanism 2 disposed below the polishing pad. Polishing head 4
Is composed of a rotating and pressing mechanism 5, a shaft 6 extending downward from the rotating and pressing mechanism 5, a holding plate 7 fixed to a lower end of the shaft 6, and the like. A backing pad 8 is adhered to the lower surface of the holding plate 7, and a wafer 10 to be polished is attracted to the backing pad 8 and set on the polishing head 4. The dressing head 11
Used for removing clogging of the polishing cloth.

Further, in the planar polishing apparatus according to the present invention,
As shown in FIG. 2A, a lattice-shaped groove 21 is formed over the entire surface of the turntable 1. Similarly,
A lattice-like groove 31 is also formed on the entire surface of the holding plate 7. In this example, as shown in FIG. 2B, each of the grooves 21 and 31 has a width of 1 mm,
It is formed with a depth of 1 mm and a pitch of 5 mm.

FIG. 3 shows another example of the pattern of the grooves formed on the surfaces of the turntable 1 and the holding plate 7.
In FIG. 3A, the groove 21 (31) is the turntable 1
The groove 21 (31) is formed by a radial curve passing through the center of the turntable 1 (holding plate 7) in FIG. 3B. Have been.

Next, a description will be given of the result of polishing a wafer by using the planar polishing apparatus according to the present invention. Turntable 1 provided with groove 21 and groove 31 shown in FIG.
After the polishing pad 3 and the backing pad 8 were bonded to the holding plate 7, respectively, the dummy wafer was held on the holding plate 7 via the backing pad 8. Then, for the purpose of eliminating air bubbles, a pressure of 600 g / c was applied.
The running-in operation was performed for 10 minutes under the conditions of m ² , the rotation speed of the turntable 1 100 rpm, and the rotation speed of the holding plate 7 at 100 rpm.

After eliminating bubbles in this manner, the 8-inch wafer 10 on which silicon oxide has been deposited is held on the holding plate 7 via the backing pad 8, and silicon oxide-based abrasive grains are suspended as an abrasive. Using the slurry, the processing pressure of the wafer was 500 g / cm ² , the rotation speed of the holding plate 7 was 20 rpm, the rotation speed of the platen 1 was 20 rpm, and the processing time was 2
Under the condition of one minute / one sheet, polishing was continuously performed on ten sheets.

The flatness after the polishing was measured by using the uniformity (U) of the processing amount shown by the following equation, and as a result, ± 5.0% was obtained. U = 100 * (Xmax−Xmin) / (Xmax + Xmin) where U: Processing amount uniformity [%] Xmax: Maximum processing amount [μm] Xmin: Minimum processing amount [μm] For comparison, a conventional plane is used. When the uniformity (U) of the processed amount was measured under the same conditions using a polishing apparatus, the value was ± 8%.

[0016]

According to the present invention, when the polishing cloth and the backing pad are respectively adhered to the turntable and the holding plate, air bubbles can be easily removed from the back side thereof by using the planar polishing apparatus according to the present invention. it can.
As a result, the flatness of the polished wafer is improved. Further, skill is less required for the work of bonding the polishing pad and the backing pad, and individual differences can be reduced.

[Brief description of the drawings]

FIG. 1 is a diagram showing an outline of a planar polishing apparatus according to the present invention.

FIG. 2 is a view showing an example of the shape of a groove formed on the surface of a turntable in the planar polishing apparatus according to the present invention;
(A) shows the plane pattern of the groove, and (b) shows the cross-sectional shape of (a).

FIG. 3 is a view showing another example of the shape of the groove formed on the surface of the turntable in the planar polishing apparatus according to the present invention;
(A) and (b) represent various examples.

FIG. 4 is a diagram showing an outline of a conventional planar polishing apparatus.

[Explanation of symbols]

1. Turntable 2. Rotation drive mechanism 3.
..Polishing cloth, 4 ... Polishing head, 5 ... Rotating and pressing mechanism, 6 ... Shaft, 7 ... Holding plate, 8 ...
..Backing pad, 9 ... Abrasive supply nozzle, 1
0 ... wafer, 11 ... dressing head, 21
... groove, 31 ... groove.

Claims (6)

[Claims] 1. A turntable having an upper surface to which a polishing cloth is adhered, and a flat backing material adsorbed and held by a backing pad disposed above the turntable opposite to the turntable and adhered to the lower surface. A polishing head that performs polishing by rotating the workpiece with the polishing head and pressing against the polishing cloth while supplying the polishing agent onto the polishing cloth, wherein bubbles are formed on the surface of the turntable. A flat polishing apparatus characterized by forming a groove for eliminating erosion. 2. The planar polishing apparatus according to claim 1, wherein the grooves are formed in a grid pattern over the entire surface of the turntable. 3. The apparatus according to claim 1, wherein the groove is formed in a radial shape passing through the center of the turntable. 4. A turntable having an upper surface to which a polishing cloth is adhered, and a plate-like material to be polished and held by a backing pad arranged above the turntable opposite to the turntable and adhered to the lower surface. A polishing head comprising: a polishing head that rotates the material to be polished by the polishing head and presses the material against the polishing cloth to perform polishing while supplying an abrasive onto the polishing cloth; A polishing apparatus characterized by forming a groove for eliminating erosion. 5. The apparatus according to claim 3, wherein the grooves are formed in a grid pattern over the entire surface of the turntable. 6. The apparatus according to claim 4, wherein the groove is formed in a radial shape passing through the center of the turntable.