JP2002217145A - Chuck for polishing apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To overcome a problem that although a conventional chuck has a cushioned property by using a porous ceramic or a rubber-like material, if a semiconductor wafer has slight tapers or irregularities in its thickness, a polish having an ultra-high accuracy uniformity cannot be realized since they are directly reflected to the polishing accuracy, and moreover, polishing sags occur in the peripheral edge of the semiconductor wafer. SOLUTION: This chuck for a polishing apparatus comprises a chuck base 1 having a concave portion on the undersurface, a gelatinous layer 2 arranged on the bottom of the concave portion of the chuck base 1, a chuck plate 3 laminated on the gelatinous layer 2, a back pad 4 laminated on the chuck plate 3, a semiconductor wafer W attached on the back pad 4, a wafer holder 5 arranged in the periphery of the semiconductor wafer W, an air bag 6 inserted between the wafer holder 5 and an edge of the chuck base 1 and an air supply route 7 arranged in the chuck base 1 connecting the air bag 6 with an air supply source.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a wrapping machine,
The present invention relates to a chuck for attaching a semiconductor wafer to a lower end of a spindle shaft of a polishing device such as a polishing machine. BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a chuck for a polishing apparatus which has uniformity of accuracy and is subjected to a polishing process, and eliminates any polishing dripping which appears on an outer peripheral edge during the polishing process.

[0002]

2. Description of the Related Art Conventionally, various kinds of chucks of a polishing apparatus of this kind have been developed and used. Semiconductor wafers to be polished in recent years have become extremely thin from the viewpoint of miniaturization of equipment to be mounted. It is the diameter enlargement from the viewpoint of productivity, the flat surface processing with uniformity with ultra-high accuracy and the mirror surface processing from the viewpoint of the yield, the ultra-thin and enlarged diameter, and At present, the brittle semiconductor wafer is being cut down on how to finish it with ultra-high accuracy.

[0003]

However, the conventional chuck has a cushioning property using a porous ceramic or rubber-like material. However, if the thickness of the semiconductor wafer has a slight inclination or unevenness, the polishing accuracy becomes poor. Therefore, it is impossible to perform polishing with ultra-high accuracy and uniformity, and furthermore, there is a problem that polishing dripping occurs on the outer peripheral edge of the semiconductor wafer.

[0004]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and as a result of diligent study, a chuck fixed to the tip of a spindle shaft of a polishing apparatus, the chuck base having a concave portion on a lower surface. And, a gel layer disposed on the bottom of the recess of the chuck base, a chuck plate laminated on the gel layer, and a back pad laminated on the chuck plate,
A semiconductor wafer to be adhered to the back pad, a wafer holder provided on the outer periphery of the semiconductor wafer, an airbag interposed between an edge portion of the chuck base and the wafer holder, and an airbag and an air supply source are connected. And an air supply system provided on the chuck base.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to eliminate the occurrence of polishing droop that appears on the outer peripheral edge when a semiconductor wafer is polished by a polishing apparatus, and to achieve ultra-high precision uniformity over the entire surface of the semiconductor wafer. It is intended to provide and provide a chuck of a polishing apparatus for performing the polishing process.

[0006]

According to the present invention, the pressure for pressing the semiconductor wafer through the chuck plate laminated on the gel layer and the back pad is provided by disposing the gel layer at the bottom of the concave portion of the chuck base. A method that enables the surface to be constantly constant, and controls the wafer holder surface with an airbag provided on the back surface to prevent drooling and apply ultra-high-precision uniform uniform polishing to the entire surface. It is.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 1 is an explanatory view showing a cross section for explaining an embodiment of a chuck for a polishing apparatus according to the present invention.

The present invention relates to a chuck for attaching a semiconductor wafer W to a lower end of a spindle shaft of a polishing device such as a lapping machine or a polishing machine,
More specifically, the pressing pressure from the back surface during the polishing process of the semiconductor wafer W is kept at a constant pressure, and the ultra-high-precision uniformity is applied to the polishing process. A chuck base 1 having a substantially cup-like shape having a concave portion 1a on the lower surface, a gel-like layer 2 disposed on the bottom of the concave portion 1a of the chuck base 1, A chuck plate 3 laminated on the gel-like layer 2, a back pad 4 laminated on the chuck plate 3, a semiconductor wafer W as an object to be polished to be detachably attached to the back pad 4, and a semiconductor wafer W A wafer holder 5 provided on the outer periphery of the chuck so as to be able to move up and down in the vertical direction and not protruding from the polishing surface, and an airbag 6 interposed between the wafer holder 5 and the edge 1b of the chuck base 1. Is obtained by a said airbag 6 and the air supply source air supply system 7 disposed in the chuck base 1 which has been connected to (not shown).

That is, in the polishing apparatus chuck of the present invention, a semiconductor wafer W is adhered to the lower surface by means of water bonding or the like, and is fixed to a lower end of a spindle shaft vertically suspended from above the polishing apparatus so as to be vertically movable. The semiconductor wafer W is pressed between a lapping plate or a polishing plate P, which is a polishing plate, disposed below and polished.

As shown in FIG. 1, the chuck base 1 is made of metal or ceramics and has a substantially cup shape having a concave portion 1a on its lower surface. It is fixed to the lower end of the shaft.

Next, the gel-like layer 2 is formed by filling a bag-like material with a gel-like substance.
It is arranged at the bottom of a.

Next, the chuck plate 3 is formed of ceramic, porous ceramic, or the like.
It is laminated on the gel layer 2.

Further, the back pad 4 is laminated on the chuck plate 3, and a recess may be formed in the back pad 4 so as to be fitted into the back pad 4, as in the illustrated embodiment. The semiconductor wafer W as the object to be polished is detachably adhered by means such as water adhesion,
As another known embodiment, the chuck plate 3 and the back pad 4 may be formed of a gas-permeable member, and a vacuum system may be provided on the chuck base 1 to perform vacuum chucking.

Further, the wafer holder 5 protects the outer peripheral edge of the semiconductor wafer W during polishing, and is provided with a protective layer on its surface by means of, for example, bonding, so that the wafer holder 5 projects vertically on the outer periphery of the semiconductor wafer W. In addition, it is provided so as not to protrude from the polished surface, and the surface is constantly flush with the polished surface of the semiconductor wafer W being polished, and is generated on the outer peripheral edge of the semiconductor wafer W. No polishing

Next, the airbag 6 is connected to the wafer holder 5.
And an edge 1 b of the chuck base 1. Air is supplied from an air supply source by an air supply system 7 to be described later, or is sucked, expands and contracts, and the wafer holder 5 This makes it possible for the surface to move up and down.

The air supply system 7 includes the chuck base 1
At the edge 1b, the base portion and the rotating shaft of
An air supply source (not shown) provided outside is connected.

In this state, the semiconductor wafer W is sandwiched between the lapping plate and the polishing plate P of the polishing plate for polishing, and a gel layer is provided at the bottom of the concave portion of the chuck base. This makes it possible to constantly maintain a constant pressure for pressing the semiconductor wafer from the back side through the chuck plate and the back pad laminated on the gel layer.

[0019]

The chuck for a polishing apparatus of the present invention constructed as described above can sufficiently cope with recent semiconductor wafers requiring ultra-high-quality polishing and finishing, and in particular, the flatness and uniformity of the semiconductor wafer. This is an epoch-making and effective invention that improves the precision of the semiconductor wafer and eliminates any polishing dripping that appears on the outer peripheral edge of the semiconductor wafer, thereby improving productivity and yield.

[Brief description of the drawings]

FIG. 1 is an explanatory view showing a cross section for explaining an embodiment of a polishing apparatus chuck of the present invention.

[Explanation of symbols]

 W Semiconductor wafer 1 Chuck base 1a Depression 1b Edge 2 Gel layer 3 Chuck plate 4 Back pad 5 Wafer holder 6 Airbag 7 Air supply system P Polishing plate

Claims (1)

[Claims] 1. A chuck fixed to a tip of a spindle shaft of a polishing apparatus, comprising a substantially cup-shaped chuck base having a concave portion on a lower surface, and a gel-shaped member provided at a bottom of the concave portion of the chuck base. Layers, a chuck plate laminated on the gel layer, a back pad laminated on the chuck plate, a semiconductor wafer which is an object to be polished to be detachably attached to the back pad, and A wafer holder provided so as to be able to protrude and retract in the direction and not protrude from the polishing surface, an airbag interposed between the wafer holder and an edge portion of the chuck base, and connecting the airbag to an air supply source. And an air supply system disposed on the chuck base.