JPH10178087A - Wafer suction table - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a wafer suction table in which a sucked wafer can be separated easily when a packing material is employed. SOLUTION: The wafer suction table 44 is made of a packing material provided with holes 44A, 44A,... in the surface for sucking a wafer 50 and through holes 44B, 44B,... are made between these holes 44A, 44A,.... When the wafer 50 is pressed against the suction face and a gap 46 on the rear side of the wafer suction table 44 is evacuated through a pressure regulator, the wafer 50 is sucked to the suction face of the wafer suction table 44. When the air is fed into the gap 46 on the rear side of the wafer suction table 44 and the pressure in the gap 46 is increased, a stripping force acts on the wafer 50 through the holes 44B, 44B,... to strip the wafer 50 from the suction face.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wafer suction table, and more particularly to a wafer suction table for sucking a wafer by the suction force of a large number of holes provided in a backing material.

[0002]

2. Description of the Related Art A polishing apparatus for polishing a wafer surface such as a semiconductor wafer sucks a wafer on a wafer suction table, and holds the wafer held on the wafer suction table while pressing the wafer against a polishing member (polishing cloth). The table is rotated to polish the wafer surface.

At present, various members and methods are used for the wafer suction table. In particular, a wafer suction table using a backing material made of a flexible material such as polyurethane is used in accordance with the shape of the wafer suction surface. Since the material is deformed, it is suitable for polishing the polishing surface of the wafer to a flat surface. A large number of holes are provided on the suction surface of such a wafer suction table. When a wafer is pressed against the suction surface, the holes are deformed (reduced), and the air inside the holes is discharged, and the shape of the holes is reduced. At the time of restoration, the pressure inside the hole becomes negative, so that a suction force acts on the wafer. This allows
The wafer is suction-held on the suction surface of the wafer suction table.

[0004]

However, in the above-mentioned wafer suction table, when the wafer that has been sucked is separated from the wafer suction table, the force for sucking the wafer cannot be released. Must be added. For this reason, there is a problem that an apparatus for damaging the wafer or separating the wafer from the wafer suction table is required, and the apparatus becomes complicated.

SUMMARY OF THE INVENTION The present invention has been made in view of such circumstances, and it is an object of the present invention to provide a wafer suction table using a backing material, which can easily peel off a sucked wafer. .

[0006]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention comprises a backing material having a large number of holes on a suction surface, wherein the wafer is suction-held on a suction surface by expansion and contraction of the holes. In the table, a hole that penetrates the wafer suction table is formed, and a gas is sent from the hole to the suction surface to give a peeling force to the wafer sucked to the suction surface, and the wafer is removed from the suction surface. It is characterized by peeling.

[0007] According to the present invention, the wafer sucked on the suction surface of the wafer suction table is depressed by sending gas into the hole penetrating the suction surface and pressed therefrom. Thus, the wafer adsorbed on the wafer adsorption table can be easily peeled off without applying external force.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A wafer suction table according to the present invention will be described below in detail with reference to the accompanying drawings. FIG. 1 is a configuration diagram of a wafer polishing apparatus to which a wafer suction table according to the present invention is applied. As shown in FIG. 1, the wafer polishing apparatus includes a polishing platen 10 and a head 18, and a wafer 50 is suction-held on a wafer suction table 44 of the head 18 with the polishing surface 50A facing downward.

The polishing platen 10 is formed in a disk shape.
A polishing cloth 14 for polishing the wafer 50 is attached to the upper surface. A spindle 16 is fixed to the lower surface of the polishing platen 10, and the spindle 16 is connected to a rotating shaft of a motor (not shown). Accordingly, by driving the motor, the polishing platen 10 rotates, and the polishing cloth 14 rotates.

The head 18 has a spindle 20 on its upper surface.
The spindle 20 is connected to a rotating shaft of a motor (not shown). Accordingly, the head 18 is rotated by driving the motor, and the wafer 50 sucked and held on the wafer suction table 44 is rotated. In addition, the head 18 is moved up and down by a drive mechanism (not shown), whereby the wafer 50 is lowered toward the polishing platen and pressed against the surface of the polishing pad 14.

With the above configuration, the wafer 50 and the polishing pad 14 are rotated, and at the same time, the wafer 50 is pressed against the polishing pad 14 and the wafer 50 is polished. still,
A slurry (grinding liquid) is supplied between the wafer 50 and the polishing cloth 14. FIG. 2 is a sectional view showing the configuration of the head 18. As shown in the figure, the head 18 has a base plate 30 on the upper part, and the base plate 30 is fixed to the head 18, whereby the head 18 is fixed to the spindle 20. The head 18 has a guide ring 32 on the side surface, and the guide ring 32 is fixed to the base plate 30 by screws 33.

A retainer ring 34 is attached to the lower surface of the guide ring 32, and surrounds the edge of the wafer 50 by the retainer ring 34. Wafer 5 during processing
When 0 is pressed against the polishing cloth 14, the retainer ring 34 is also pressed against the polishing cloth, and uneven distribution of the polishing pressure on the edge of the wafer 50 is suppressed. The above base plate 30
An air chamber 36 is formed in the lower part of. This air chamber 36
Is sealed by an elastic film 38 sandwiched between the base plate 30 and the guide ring 22, and the air chamber 3
The air pressure is adjusted to an arbitrary value by a pressure adjusting device (not shown) through an air supply passage 37 communicating with the pressure adjusting device 6. Thereby, the pressure for pressing the wafer 50 against the polishing pad 14 can be adjusted.

A cylindrical member 40 is fitted below the air chamber 36, and the cylindrical member 40 is locked to a guide ring 52 by a fall prevention pin (not shown) (it can be finely moved vertically). A carrier 42 is fixed to the lower part of the columnar member 40 by screws 43, and a wafer suction table 44 is fixed to a lower part of the carrier 43.

When a gap 46 on the back surface is evacuated through an air passage 45 communicating with a pressure regulator (not shown), the wafer suction table 44 holds the wafer 50 on the front surface. FIG. 3 is a sectional view of a main part showing the structure of the wafer suction table 44. The wafer suction table 44 shown in the figure is made of a backing material made of a flexible material such as polyurethane, cellulose acetate, and polyester. As shown in the figure, the wafer suction table 44 has a large number of holes (pits) 44A, 44A,... On a suction surface for sucking the wafer 50, and the wafer is held between these pits 44A, 44A,. Holes 44B, 44B,... Penetrating the front and back of the suction table 44 are formed. A gap 46 is provided on the back surface of the wafer suction table 44B, and an air passage 45 communicating with a pressure adjusting device for adjusting the air pressure is connected to a part of the gap 46.

Accordingly, the air pressure in the gap 46 is adjusted by the pressure adjusting device, and the suction force for sucking the wafer through the holes 44B, 44B,... Can act. According to the wafer suction table 44 configured as described above, when the wafer 50 is sucked to the wafer suction table 44, the wafer 50 is pressed against the suction surface of the wafer suction table 44 and the pits 44 are pressed.
A, 44A,... Are once deformed to reduce the pressure in the pits, and the pressure in the gap 46 is reduced by the pressure adjusting device (the inside of the gap is evacuated). As a result, a suction force acts on the wafer 50 pressed against the suction surface of the wafer suction table 44, and the wafer 50 can be suctioned to the wafer suction table 44.

On the other hand, when the wafer 50 is separated from the wafer suction table 44, the gap 4 is controlled by the pressure adjusting device.
Increase the air pressure of 6. That is, air is sent from the air passage 45 into the gap 46 to increase the pressure in the gap 46. As a result, a pressing force acts on the entire surface of the suction surface of the wafer 50 sucked by the wafer suction table 44 in a direction in which the wafer 50 is separated from the wafer suction table 44.
4, the wafer 50 can be peeled off.

In the above embodiment, when the wafer 50 is sucked on the wafer suction table 44, the gap 46
Are reduced by the suction force of the holes 44B, 44B,..., But the wafer 50 may be suctioned only by the suction force of the pits 44A, 44A,. That is, when the wafer 50 is sucked, the gap 46 does not necessarily need to be evacuated.

[0018]

As described above, according to the wafer suction table according to the present invention, the wafer sucked on the suction surface of the wafer suction table is pressed by sending gas into the hole penetrating through the suction surface to press the wafer from the suction surface. Peel off. Thus, the wafer adsorbed on the wafer adsorption table can be easily peeled off without applying external force.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a wafer polishing apparatus to which a wafer suction table according to the present invention is applied.

FIG. 2 is a cross-sectional view showing a configuration of a head 18.

FIG. 3 is a cross-sectional view showing a structure of a wafer suction table.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 ... Polishing surface plate 14 ... Polishing cloth 18 ... Head 20 ... Spindle 30 ... Base plate 32 ... Guide ring 34 ... Retainer ring 36 ... Air chamber 38 ... Elastic film 40 ... Cylindrical member 42 ... Carrier 44 ... Wafer suction table 44A ... Pit 44B ... holes 45 ... air passages 46 ... gaps 50 ... wafers

Claims (1)

[Claims] 1. A wafer suction table comprising a backing material having a large number of holes on a suction surface and holding the wafer on the suction surface by expansion and contraction of the holes, wherein a hole penetrating through the wafer suction table is formed. A wafer suction table, wherein a gas is sent from the hole to the suction surface to apply a peeling force to the wafer sucked on the suction surface, thereby separating the wafer from the suction surface.