JP7046495B2 - Holder and method of manufacturing the holder - Google Patents

Description

The present invention generally relates to a holder and a method for manufacturing the holder, and more particularly to a holder used when polishing a plate-shaped object to be polished with a polishing pad and a method for manufacturing the holder.

Polishing cloth is used for plate-shaped objects to be polished such as glass substrates for flat panel displays (FPDs), color filters, silicon wafers, and substrates with indium tin oxide (ITO) film formation, which require high-precision flatness. The polishing process used is often applied.

A single-sided polishing machine that polishes the object to be polished one side at a time is used for polishing the object to be polished. In this single-sided polishing machine, the object to be polished is held on the holding surface plate, and the polishing pad is attached to the polishing surface plate. At the time of polishing, the holding platen and the polishing platen are arranged relative to each other so that the object to be polished comes into contact with the polishing pad, and the polishing liquid containing the polishing particles is supplied to the polishing pad to apply pressure to the object to be polished. The object to be polished is polished by rotating both fixed plates while applying.

In such a single-sided polishing machine, a backing material formed of an elastic resin or the like on the holding surface plate in order to suppress scratches on the object to be polished caused by direct contact of the object to be polished with the metal holding surface plate. Is attached, and the object to be polished is pressed against the polishing pad through this backing material. Further, since lateral displacement of the object to be polished occurs during the polishing process, the frame material is attached along the peripheral edge of the backing material, and the object to be polished is pressed against the polishing pad by the holder composed of the backing material and the frame material. (Patent Document 1).

Here, as a frame material for the holder, a laminated glass epoxy plate has been conventionally used. The laminated glass epoxy plate is manufactured by laminating, heating, compressing and curing a glass fiber cloth and an epoxy resin.

Such a laminated glass epoxy plate is cut into a ring shape having a thickness and dimensions according to the shape of the object to be polished and the polishing machine / polishing method, and is used as a frame material.

Japanese Unexamined Patent Publication No. 2009-208199

It is known that if the pressure applied to the object to be polished from the polishing pad and the backing material is uneven during polishing, the surface shape of the object to be polished after polishing becomes non-uniform. Therefore, in the configuration of Patent Document 1, the frame material (ring) attached to the outer periphery of the backing material (elastic pad) of the holder is polished (wrapped) to eliminate the variation in the thickness of the frame material (ring). The surface shape of the object to be polished after polishing was made uniform.

However, in recent years, the size of the object to be polished has increased or the diameter has increased, and the surface of the object to be polished after polishing has been required to have higher surface accuracy (flatness). Although the demand for the accuracy of the members is increasing, there is a problem that the required high surface accuracy (flatness) cannot be achieved by polishing using such a conventional holder.

The present invention has been made to cope with such a problem, and it is an object of the present invention to provide a holder capable of improving the surface accuracy of an object to be polished after polishing and a method for manufacturing such a holder. The purpose.

As a result of intensive research to improve the surface accuracy of the object to be polished after polishing, the inventor of the present invention has determined that the flatness of the frame material and the backing material constituting the holder is the surface accuracy of the object to be polished after polishing. It has been newly found that the flatness of the frame material has a great influence on the surface accuracy of the object to be polished, and the present invention has been made based on this new finding.

According to the invention of the present application
A holder used when polishing a plate-shaped object to be polished with a polishing pad.
An elastic resin backing material having an object holding surface that abuts on the back surface of the object to be polished and pressing the object to be polished against the polishing pad on the object holding surface.
A thin plate-shaped frame material attached to the backing material so as to surround the object holding surface of the backing material is provided.
The difference in height position between the peripheral edge and the central portion of the object holding surface to be polished is within 0.6% of the delivery of the object holding surface to be polished.
A retainer characterized by that is provided.

By polishing the plate-shaped object to be polished with the polishing pad using the holder having such a configuration, the pressure applied to the object to be polished from the polishing pad held by the holder becomes uniform, and as a result, the pressure is made uniform. The accuracy (flatness) of the surface of the object to be polished after polishing can be improved.

According to another preferred embodiment of the present invention, the difference in height position between the outer edge and the inner edge of the frame material is within 0.2% of the width of the frame material.

According to another preferred embodiment of the invention.
The object holding surface of the backing material has a substantially circular shape, and the transfer is the diameter of the circle.
The frame material has the shape of a ring, and the width is the radial length of the ring.

According to another preferred embodiment of the invention.
The shore A hardness of the backing material is 50 to 90.

In a holder composed of a backing material having a hardness in such a range, the accuracy (flatness) of the surface of the object to be polished after polishing is set by setting the difference in height position between the backing material and the frame material within the above range. ) Can be increased more effectively.

According to another preferred embodiment of the invention.
The compressibility of the backing material is 3 to 30%.

In a holder composed of a backing material having a compression rate in such a range, the accuracy (flatness) of the surface of the object to be polished after polishing is set by setting the difference in height position between the backing material and the frame material within the above range. Degree) can be increased more effectively.

According to another preferred embodiment of the invention.
The frame material is a glass epoxy resin.

According to another aspect of the invention.
A method for manufacturing a holder used when polishing a plate-shaped object to be polished with a polishing pad.
The step of laminating boards of hard resin material and
The step of heating the laminated hard resin material plate while pressurizing it in the laminating direction to raise the temperature to a predetermined temperature, and
A step of continuing heating for a predetermined time so as to maintain the predetermined temperature while pressurizing the laminated plate of the hard resin material in the laminating direction.
A step of stopping the heating while pressurizing the laminated hard resin material plate in the laminating direction and allowing the laminated hard resin material plate to cool.
A step of cutting a plate of the hard resin material that has been allowed to cool into a predetermined shape and using it as a frame material.
The frame material has an object holding surface that abuts on the back surface of the object to be polished, and the object holding surface of the elastic resin backing material that presses the object to be polished against the polishing pad on the object holding surface. With steps to attach to,
A method of manufacturing a retainer is provided.

According to such a configuration, it is possible to provide a holder in which the difference in height position between the peripheral edge and the central portion of the surface for holding the object to be polished and the difference in height position between the outer edge and the inner edge of the frame material are reduced. Can be done.

According to the present invention having such a configuration, a holder capable of increasing the surface accuracy of the object to be polished after polishing is provided.

Further, according to the present invention having such a configuration, there is provided a method for manufacturing a holder capable of increasing the surface accuracy of the object to be polished after polishing.

It is a schematic perspective view which shows the structure of the single-sided grinding machine which uses the holder by embodiment of this invention. It is a schematic vertical sectional view which shows the holder of a preferable embodiment of this invention in a state of use. It is a schematic vertical sectional view for demonstrating the difference in the height position of each part of the holder of FIG. It is a schematic sectional drawing for demonstrating the manufacturing method of the holder of embodiment of this invention. It is a schematic cross-sectional view for demonstrating the method of measuring the dimension of the holder of the Example of this invention. It is a schematic cross-sectional view for demonstrating the method of measuring the dimension of the holder of the Example of this invention. It is a schematic cross-sectional view for demonstrating the method of measuring the dimension of the holder of the Example of this invention. It is a graph which shows the measurement result of the dimension of the holder of the Example of this invention. It is a graph which shows the measurement result of the dimension of the holder of the comparative example of this invention.

Hereinafter, a holder according to a preferred embodiment of the present invention and a method for manufacturing the holder will be described with reference to the drawings.

First, a single-sided grinding machine in which the holder 10 according to the embodiment of the present invention is used will be described with reference to FIG. FIG. 1 is a schematic perspective view showing the configuration of a single-sided grinding machine 1 in which the holder 10 according to the embodiment of the present invention is used.

As shown in FIG. 1, the single-sided polishing machine 1 includes a disk-shaped polishing surface plate 2. A shaft 4 that is rotationally driven by a drive source such as a motor is connected to the center of the back surface of the polishing surface plate 2, and the polishing surface plate 2 is rotatable about the central axis X. Further, a disk-shaped polishing pad 6 is attached to the upper surface of the polishing surface plate 2.

The polishing head 8 is arranged on the polishing pad 6 at a position eccentric from the central axis X. The holder 10 of the present embodiment is attached to the bottom of the polishing head 8. Then, an object to be polished such as a silicon wafer is held between the holder 10 and the polishing pad 2, and the object to be polished is polished. A shaft 9 that is rotationally driven by a drive source (not shown) such as a motor is also connected to the polishing head 8 so that it can rotate (rotate) about the central axis X'.

FIG. 2 is a vertical cross-sectional view showing a holder 10 attached to the single-sided grinding machine 1 and supporting the object to be polished W. The holder 10 includes a substantially disk-shaped backing material 12 having a substantially constant thickness throughout. A ring-shaped frame member 16 that covers the outer edge of the one surface of the backing material 12 is attached to one surface 14 (lower surface) of the backing material 12. The outer diameter of the frame material 16 is set to be substantially equal to the outer diameter of the backing material 12. Further, the portion of one surface of the backing material 12 surrounded by the frame material 16 is the object holding surface 18 that comes into contact with the back surface of the object W to be polished during polishing.

In this embodiment, the backing material 12 is made of an elastic resin. As the elastic resin, for example, polyurethane resin, epoxy resin, unsaturated polyester resin and the like can be used, but polyurethane resin is preferable from the viewpoint of chemical resistance, processability, adjustment of viscoelastic properties, and strength. Further, it is preferable to have air bubbles from the viewpoint of cushioning property and retention property for the object to be polished.

As the backing material 12, it is preferable to use an elastic resin having a shore A hardness of about 50 to 90 (for example, foamed polyurethane), and more preferably an elastic resin having a shore A hardness of about 60 to 80 (for example, foamed polyurethane). It is better to use. Here, the shore A hardness can be determined according to the Japanese Industrial Standards (JIS K 7215).

By setting the hardness of the backing material 12 within the above range, it is possible to prevent damage to the wafer holding surface during holding of the wafer W and deterioration of performance due to deterioration of cushioning property.

Further, the backing material 12 is preferably made of a material having a compression ratio of 3 to 30%.
By setting the compression ratio within the above range, it is possible to maintain the cushioning property for the object W to be polished and the flatness of the holding surface of the backing material 12 and prevent the backing material 12 from deteriorating the followability to the shape of the object to be polished. can.

Here, the compressibility can be determined by using a shopper type thickness measuring instrument (pressurized surface: circular with a diameter of 1 cm) in accordance with Japanese Industrial Standards (JIS L 1021). Specifically, the thickness t ₀ after being pressurized with the initial load for 30 seconds was measured, and then the thickness t ₁ after being left for 5 minutes under the final pressure was measured. The compression rate can be calculated by the compression rate (%) = (t ₀ − t ₁ ) / t ₀ × 100.

The frame material 16 is attached to one surface 14 of the backing material 12 by using an adhesive or the like so that the outer circumference coincides with the outer circumference of the holding surface of the backing material 12. The frame material 16 is formed of a relatively hard resin material, for example, a glass epoxy resin, which has been subjected to a heat treatment (hereinafter, referred to as “baking treatment”) as described later.

Further, in the present embodiment, the difference 18h in the height position between the peripheral edge 18e of the object holding surface 18 of the holder 10 and the central portion 18c is 0.6% of the transfer (diameter) 18d of the object holding surface 18. Within (Fig. 3).
In addition, although FIG. 3 shows a mode in which the holder 10 is convex downward so that the central portion 18c becomes a valley, there is also a mode in which the central portion becomes a mountain, contrary to the mode of FIG. It is assumed, and even in such a case, it is the subject of the present invention.

In the present embodiment, the object holding surface 18 of the backing material 12 is substantially circular and has a diameter of about 100 to 450 mm. The thickness of the backing material 12 is about 0.15 to 0.9 mm.

Further, in the holder 10, the difference in height position 16h between the outer edge 16o and the inner edge 16i of the frame member 16 is within 0.2% of the width 16w of the frame member.

In the present embodiment, as described above, the frame material 16 has a ring shape, and the width (diameter length) 16w is about 20 to 30 mm. The thickness of the frame material 16 is about 0.2 to 1.0 mm.

Next, a method of manufacturing the holder 10 will be described.
In the method for manufacturing the holder 10 of the present embodiment, a frame material 16 made of a baking-treated resin plate is used.

First, a plurality of glass epoxy resin plates (for example, 25 plates) are laminated and installed in a constant temperature bath 30 at room temperature. Stainless steel (SUS) plates 32, 32 are arranged above and below the laminated resin plates via the glass epoxy resin plates 34, 34 (FIG. 4). The stacked resin plates are pressurized (for example, 10 kgf / cm ² ) in the stacking direction (vertical direction) by a stainless steel (SUS) plate 32 or the like.

Next, while maintaining the pressurized state for the stacked resin plates, the temperature inside the constant temperature bath 30 is raised, the stacked resin plates are heated, and the temperature is raised to a predetermined temperature (for example, 125 ° C.).
Next, in the constant temperature bath 30 for a predetermined time (for example, 4 hours) so that the stacked resin plates are maintained at a predetermined temperature (for example, 150 ° C.) while maintaining the pressurized state for the stacked resin plates. Continue to control the temperature.
The temperature at which the resin plate is heated can be appropriately changed depending on the material of the resin plate, and is preferably a temperature at which the shape of the resin plate can be easily corrected, for example, a softening temperature or a glass transition temperature.

Next, while maintaining the pressurized state for the stacked resin plates, the temperature control in the constant temperature bath 30 is completed, and the stacked resin plates are allowed to cool to about room temperature (for example, about 6 hours) in the stacked state. ..
Further, after the temperature in the constant temperature bath 30 drops to room temperature, the stainless steel (SUS) plates 32 and 32 are removed, and the stacked resin plates are taken out from the constant temperature bath 30.

Finally, the resin plates are removed from the stacked resin plates, and the individual resin plates are cut into a ring shape to form a ring-shaped frame material 16, which is used as the material holding surface 18 of the elastic resin backing material 12. Fix it with an adhesive or the like. The step of cutting into a ring shape may be performed before the baking process.

By stacking the resin plates that are the material of the frame material 16 and heating and maintaining the heated state under pressure, and then gradually allowing it to cool, the distortion given to the resin plate made of glass epoxy during manufacturing is alleviated. Will be done. By cooling to room temperature over time, the flatness of the resin plate is improved. By reducing the distortion of the resin plate, the difference in height position (position in the thickness direction) between the inner edge and the outer edge in the width direction (diameter direction) of the ring-shaped frame material 16 manufactured from the resin plate is reduced. do. That is, the distortion of the frame material 16 is reduced.

As a result, when the frame material 16 is attached to the backing material 12, the distortion (deformation or bending) of the object holding surface 18 of the backing material 12 due to the distortion of the frame material 16 is suppressed.

Next, the holder of the embodiment of the present invention will be described.
In the embodiment of the present invention, 25 resin plates made of glass epoxy resin having a side of 500 mm square are laminated, and 18 kg stainless steel (SUS) plates having a size of 500 mm square are placed above and below the glass epoxy resin plate via a glass epoxy resin plate and a release paper. The laminated body constructed by arranging the layers was installed in a constant temperature bath. Then, the temperature in the constant temperature bath was raised to 150 ° C., and this state was maintained for 4 hours.

Next, the temperature control of the constant temperature bath was stopped, the laminated resin plates were allowed to cool, the temperature in the constant temperature bath was lowered to room temperature, and then the laminated resin plates were taken out from the constant temperature bath. Finally, the resin plates were removed one by one from the stacked resin plates, and the individual resin plates were cut into a ring shape to produce a ring-shaped frame material. Then, this single frame material was attached to the object holding surface of the elastic resin backing material with an adhesive or the like to form a holder. The backing material of the elastic resin was a foamed sheet made of polyurethane resin formed by a wet film forming method. Further, a double-sided tape for attaching to a base material such as PET or a holding surface plate was attached to the opposite surface side of the holding surface of the backing material.

The dimensions of the holder manufactured by such a method were measured by the methods shown in FIGS. 5 and 6. Hereinafter, this measurement method will be described.
First, the holder 10 was arranged on the ring-shaped pedestal 52 arranged on the surface plate 50 in the direction in which the frame material faces upward. Next, two fixing weights 54 were placed at intervals at each of the two positions facing each other in the radial direction of the frame material.

In this state, while moving the laser measuring instrument L so as to traverse the holder 10 in the radial direction through between the two weights 54 and 54 (arrow A), the surface of the holder (arrow A) is moved by the laser measuring instrument L. That is, the height positions of the upper surface of the frame material and the pad support surface) were continuously measured, and the results as illustrated in the graph in FIG. 7 were obtained.

Table 1 shows the measurement results of the holders of Examples and Comparative Examples of the present invention, FIG. 8 is a graph showing the measurement results of the holders of Examples of the present invention, and FIG. 9 shows the holders of Comparative Examples. It is a graph which shows the measurement result. The holder of the comparative example is a holder formed by using a frame material that has not been pressurized or heat-treated (baked) in a constant temperature bath.

As is clear from Tables 1, 8 and 9 below, in the holder of the example using the frame material subjected to the baking treatment, the frame material portion is substantially flat (the difference in height position between the outer edge and the inner edge is extremely large). The difference in height position between the peripheral edge and the central portion of the surface for holding the object to be polished is also smaller than that of the holder in the comparative example.

In the holder of this embodiment, the difference in height position between the peripheral edge and the central portion of the object holding surface to be polished is about 0.5% of the transfer (diameter) of the object holding surface, and the outer edge of the frame material. The difference in height position between and the inner edge is almost zero.

Not limited to the above-described embodiment of the present invention, various modifications and modifications can be made within the scope of the technical idea described in the claims.

Further, the silicon wafer was polished using the holders of Examples and Comparative Examples under the following polishing conditions, and the performance of the holder was evaluated by the polishing rate. The polishing rate is one of the numerical values indicating the polishing efficiency when the object to be polished is polished by the polishing pad, and this time, the polishing rate was calculated from the polishing area and the specific gravity of the polished object per minute.

Polishing conditions Used polishing machine: MCP-150X manufactured by Nachi-Fujikoshi Co., Ltd.
Polishing pad: Fujibo Ehime, # 27
Rotation speed: (Surface plate) 60r / m (Top ring) 50r / m
Polishing pressure: 100 g / m ²
Swing width: 10 mm (200 mm from the swing center value)
Swing movement: 1 mm / min
Abrasive: Granzox3900RS manufactured by Fujimi Incorporated Co., Ltd.
(Use a mixture of diluted concentration stock solution: water = 1:19)
Object to be polished: 8 inch φ silicon wafer (thickness 750 μm)
Polishing time: 20 minutes

In the measurement of the polishing rate, the polishing rate of the comparative example was set to 1.0, the polishing rate of the example was shown in comparison with the polishing rate of the comparative example, and the results are shown in Table 1. If the surface accuracy (flatness) of the holder is high, it is presumed that the surface accuracy of the holder is lowered due to the distortion of the frame material, and the polishing rate is lowered due to non-uniform contact of the object to be polished. When the polishing rate is good, it is judged that the entire surface of the object to be polished is in contact with the polishing pad flatly, and the flatness of the holder is excellent.

As shown in Table 1, the polishing rate of the holder of the example is significantly improved to 1.1 with respect to the polishing rate of 1 of the holder of the comparative example, and it is presumed that the surface accuracy is improved.

While moving the laser measuring instrument L so as to cross the 500 mm square 700 μm glass epoxy resin plate before the baking process in a straight line direction, the laser measuring instrument L continuously positions the height of the surface of the resin plate. It was measured. As a result, a convex or concave warp of about 1 to 4 mm was observed, but the warp of 0.5 mm or less was suppressed in the resin plate after the baking treatment, and a flat resin plate could be obtained.

1: Single-sided polishing machine 10: Holder 12: Backing material 16: Frame material 16o: Outer edge 16i: Inner edge 18: Object holding surface 18e: Edge edge 18c: Central portion 18d: Diameter

Claims (1)

A method for manufacturing a holder used when polishing a plate-shaped object to be polished with a polishing pad.
A step of laminating multiple plates made of glass epoxy resin with a thickness of 0.2 to 1.0 mm ,
A step of heating the laminated board while pressurizing it at a pressure of 0.0072 kg / cm ² in the stacking direction to raise the temperature to 150 degrees Celsius.
A step of continuing heating for 4 hours so as to maintain the temperature while pressurizing the laminated plates in the stacking direction.
A step of stopping the heating while pressurizing the laminated boards in the stacking direction and allowing the laminated boards to cool.
A step of removing the cooled laminated boards one by one and cutting them into a ring shape to make a frame material.
The frame material has an object holding surface that abuts on the back surface of the object to be polished, and the object holding surface of the elastic resin backing material that presses the object to be polished against the polishing pad on the object holding surface. When the frame material is arranged in the upward direction, the difference in height position between the peripheral edge and the central portion of the object holding surface exposed inside the ring-shaped frame material is reduced. It comprises a step of forming a retainer that is within 0.6% of the diameter of the object holding surface exposed inside the ring-shaped frame .
How to manufacture the holder.

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