JP2018161732A - Holder and manufacturing method for holder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a holder that is able to improve surface accuracy after a large-sized object to be polished is polished and to provide a manufacturing method for such a holder.SOLUTION: Provided is a holder 10 used for polishing, with an abrasive pad, a plate-like object to be polished, comprising: a packing material 12 made of elastic resin, which has a holding surface, which holds an object to be polished, the holding surface being in contact with a rear surface of the object; and a frame material 16 in the form of a thin plate, which is mounted on the packing material so as to surround the holding surface of the packing material. The height difference 18h between a peripheral edge 18e and a central part 18c of the holding surface is equal to or less than 0.6% of a diameter 18d of the holding surface. The height difference 16h between an outer edge 16o and an inner edge 16i of the frame material is equal to or less than 0.2% of the width 16w of the frame material.SELECTED DRAWING: Figure 3

Description

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

  Use a polishing cloth for plate-like objects to be polished such as glass substrates for flat panel displays (FPD), color filters, silicon wafers, indium tin oxide (ITO) film-formed substrates that require high-precision flatness. The polishing process used is often applied.

  For polishing the object to be polished, a single-side polishing machine that polishes the object to be polished one side at a time is used. In this single-side polishing machine, an object to be polished is held on a holding surface plate, and a polishing pad is attached to the polishing surface plate. At the time of polishing, the holding surface plate and the polishing surface plate are arranged relative to each other so that the object to be polished contacts the polishing pad, a polishing liquid containing abrasive particles is supplied to the polishing pad, and pressure is applied to the object to be polished. The object to be polished is polished by rotating both surface plates while applying.

  In such a single-side polishing machine, a backing material formed of an elastic resin or the like on the holding surface plate in order to suppress scratching of the object to be polished caused by the object to be polished coming into direct contact with the metal holding surface plate And the object to be polished is pressed against the polishing pad through the backing material. Furthermore, since the lateral displacement of the object to be polished occurs during the polishing process, a frame material is attached along the periphery of the backing material, and the object to be polished is pressed against the polishing pad by a holder constituted by the backing material and the frame material. (Patent Document 1).

  Here, a glass epoxy laminate is conventionally used as a frame material for the holder. A glass epoxy laminate is manufactured by laminating a glass fiber fabric and an epoxy resin, and heating and compressing them.

  Such a glass epoxy laminate is cut into a ring shape having a thickness and dimensions according to the shape of the workpiece and the polishing machine / polishing method, and used as a frame material.

JP 2009-208199 A

  It is known that when the pressure applied to the object to be polished from the polishing pad and the backing material during polishing is uneven, the surface shape of the object to be polished after polishing becomes non-uniform. For this reason, 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 variations in the thickness of the frame material (ring). The surface shape of the polished object after polishing was made uniform.

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

  The present invention has been made to cope with such problems, and provides a holder capable of increasing the surface accuracy of an object to be polished after polishing, and a method for manufacturing such a holder. Objective.

  The inventor of the present invention has conducted extensive research to improve the surface accuracy of the object to be polished after polishing. As a result, 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. In particular, the present inventors have found that the flatness of the frame material has a great influence on the surface accuracy of the object to be polished, and made the present invention based on this new knowledge.

According to the present invention,
A holder used when polishing a plate-shaped object to be polished with a polishing pad,
A backing material made of an elastic resin that has an object holding surface that contacts the back surface of the object to be polished and presses the object to be polished against the polishing pad with the object holding surface;
A thin plate-like frame member attached to the backing material so as to surround the polishing object holding surface of the backing material,
The difference in height position between the peripheral edge and the center of the workpiece holding surface is within 0.6% of the passing of the workpiece holding surface,
A holding device is provided.

  By polishing the plate-like 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 accuracy (flatness) of the surface of the object to be polished after polishing can be increased.

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

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

According to another preferred embodiment of the invention,
The backing material has a Shore A hardness of 50 to 90.

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

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

  In a holder made of a backing material with a compression ratio in such a range, by setting the difference in height position between the backing material and the frame material within the above range, the accuracy (flatness) of the surface of the object to be polished after polishing is set. 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 of manufacturing a holder used when a plate-like object to be polished is polished with a polishing pad,
Laminating a plate of hard resin material;
Heating the laminated hard resin material plate while pressing in the laminating direction, and raising the temperature to a predetermined temperature;
Continuing the heating for a predetermined time so as to maintain the predetermined temperature while pressing the laminated hard resin material plate in the laminating direction;
While pressing the laminated hard resin material plate in the laminating direction, stopping the heating, and allowing the laminated hard resin material plate to cool;
Cutting the plate of the hard resin material that has been allowed to cool into a predetermined shape to form a frame material; and
A polishing object holding surface of an elastic resin backing material that has a polishing object holding surface that abuts the frame material against the back surface of the polishing object and presses the polishing object against a polishing pad by the polishing object holding surface. A step of attaching to,
A method for 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 workpiece holding surface and the difference in height position between the outer edge and the inner edge of the frame member are reduced. Can do.

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

  Moreover, according to this invention which has such a structure, the manufacturing method of the holder | retainer which can make the to-be-polished surface accuracy after grinding | polishing high can be provided.

It is a schematic perspective view which shows the structure of the single-side polisher in which the holder by embodiment of this invention is used. It is a typical longitudinal section showing a holder of a preferred embodiment of the present invention in use condition. It is a typical longitudinal cross-sectional view for demonstrating the difference in the height position of each part of the holder of FIG. It is typical sectional drawing for demonstrating the manufacturing method of the holder of embodiment of this invention. It is typical sectional drawing for demonstrating the method to measure the dimension of the holder of the Example of this invention. It is typical sectional drawing for demonstrating the method to measure the dimension of the holder of the Example of this invention. It is typical sectional drawing for demonstrating the method to measure 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 the present invention. It is a graph which shows the measurement result of the dimension of the holder of the comparative example of the present 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-side polishing 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 a configuration of a single-side polishing machine 1 in which a holder 10 according to an embodiment of the present invention is used.

  As shown in FIG. 1, the single-side 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 so that the polishing surface plate 2 can rotate about the central axis X. A disc-shaped polishing pad 6 is attached to the upper surface of the polishing surface plate 2.

  A polishing head 8 is disposed on the polishing pad 6 at a position eccentric from the central axis X. The holder 10 of this 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 driving 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 longitudinal sectional view showing the holder 10 attached to the single-side polishing machine 1 and supporting the workpiece W. The holder 10 includes a substantially disc-shaped backing material 12 having a substantially constant thickness throughout. On one surface 14 (lower surface) of the backing material 12, a ring-shaped frame material 16 that covers the outer edge portion of the one surface is attached. The outer diameter of the frame member 16 is set to be approximately equal to the outer diameter of the backing member 12. In addition, a portion surrounded by the frame material 16 on one surface of the backing material 12 is a polished object holding surface 18 that comes into contact with the back surface of the polished object W during polishing.

  In the present embodiment, the backing material 12 is formed of an elastic resin. As this elastic resin, for example, a polyurethane resin, an epoxy resin, an unsaturated polyester resin, and the like can be used, and a polyurethane resin is preferable from the viewpoint of chemical resistance, processability, adjustment of viscoelastic properties, and strength. Moreover, it is preferable that it has a bubble from a viewpoint of the cushioning property with respect to to-be-polished material, or a retainability.

  As the backing material 12, it is preferable to use an elastic resin (for example, foamed polyurethane) having a Shore A hardness of about 50 to 90, more preferably an elastic resin (for example, foamed polyurethane) having a Shore A hardness of about 60 to 80. It is good to use. Here, the Shore A hardness can be determined in accordance with Japanese Industrial Standard (JIS K 7215).

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

Moreover, it is preferable that the backing material 12 is comprised with the material whose compression rate is 3 to 30%.
By setting the compression rate within the above range, the cushioning property against the workpiece W and the flatness of the holding surface of the backing material 12 can be maintained, and the followability of the backing material 12 with respect to the workpiece shape can be prevented from being lowered. it can.

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

  The frame member 16 is attached to one surface 14 of the backing material 12 using an adhesive or the like so that the outer periphery coincides with the outer periphery of the holding surface of the backing material 12. The frame member 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 process”) as will be described later.

In this embodiment, the difference 18h in the height position between the peripheral edge 18e and the central portion 18c of the workpiece holding surface 18 of the holder 10 is 0.6% of the handing (diameter) 18d of the workpiece holding surface 18. (Figure 3).
In addition, in FIG. 3, although the holder 10 shows the aspect which protrudes below so that the center part 18c may become a trough, the aspect which a center part becomes a mountain contrary to the aspect of FIG. It is assumed that such a case is also an object of the present invention.

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

  Further, in the holder 10, the height position difference 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 member 16 has a ring shape, and the width (radial length) 16w is about 20 to 30 mm. Further, the thickness of the frame member 16 is set to about 0.2 to 1.0 mm.

Next, a method for manufacturing the holder 10 will be described.
In the manufacturing method of the holder 10 of the present embodiment, a frame member 16 made of a resin plate that has been baked is used.

First, a plurality of (for example, 25) glass epoxy resin plates are stacked and placed in a constant temperature bath 30 at room temperature. Stainless steel (SUS) plates 32 and 32 are disposed above and below the laminated resin plates via glass epoxy resin plates 34 and 34 (FIG. 4). The stacked resin plates are pressed (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 with respect to the stacked resin plates, the temperature inside the thermostat 30 is increased, and the stacked resin plates are heated to a predetermined temperature (for example, 125 ° C.).
Next, in the thermostatic chamber 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 a pressurized state with respect to the stacked resin plates. Continue temperature control.
The temperature at which the resin plate is heated can be appropriately changed according to 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, near the softening temperature or the glass transition temperature.

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

  Finally, the resin plates are removed from the stacked resin plates, and each resin plate is cut into a ring shape to form a ring-shaped frame material 16, and this frame material 16 is used as the polishing object holding surface 18 of the elastic resin backing material 12. Secure with adhesive. In addition, you may perform the process cut | disconnected in a ring shape before the said baking process.

  The resin plate used as the material of the frame material 16 is stacked, and the baking applied to the glass epoxy resin plate is alleviated by baking that maintains heating and heating in a pressurized state and gradually cools. Is done. The flatness of the resin plate is improved by cooling to room temperature over time. 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 (radial direction) of the ring-shaped frame 16 manufactured from the resin plate is reduced. To do. That is, the distortion of the frame member 16 is reduced.

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

Next, the holder according to the embodiment of the present invention will be described.
In the embodiment of the present invention, 25 glass epoxy resin plates each having a 500 mm square are laminated, and 18 kg stainless steel (SUS) plates of 500 mm square are placed on the upper and lower sides of the glass epoxy resin plate and release paper. The laminated body constituted by arranging the components was placed in a thermostatic bath. Subsequently, the temperature in the thermostat was raised to 150 ° C., and this state was maintained for 4 hours.

  Next, the temperature control of the thermostatic bath was stopped, the laminated resin plates were allowed to cool, and after the temperature in the thermostatic bath was lowered to room temperature, the laminated resin plates were taken out from the thermostatic bath. Finally, the resin plates were removed one by one from the stacked resin plates, and each resin plate was cut into a ring shape to produce a ring-shaped frame material. Then, this frame member was attached to an object-holding surface of an elastic resin backing material with an adhesive or the like to obtain a holder. The elastic resin backing material was a polyurethane resin foam sheet formed by a wet film formation method. Moreover, the double-sided tape for affixing on a base material made from PET, etc. and a holding surface plate was affixed on the opposite surface side of the holding surface of a backing material.

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

  In this state, the laser measuring device L is moved (arrow A) so as to cross the holding device 10 in the radial direction through the two weights 54, 54, and the surface of the holding device (with the laser measuring device L ( That is, the height positions of the upper surface of the frame member and the pad support surface were measured continuously, and the results illustrated in the graph of FIG. 7 were obtained.

  Table 1 shows the measurement results of the holders of the examples and comparative examples of the present invention, FIG. 8 is a graph showing the measurement results of the holders of the examples of the present invention, and FIG. 9 shows the results of the holders of the comparative examples. It is a graph which shows a measurement result. The holder of a comparative example is a holder formed using a frame material that has not been subjected to pressurization and heat treatment (baking treatment) in a thermostatic bath.

  As apparent from Table 1 and FIGS. 8 and 9, in the holder of the example using the frame material subjected to the baking process, the frame material portion is substantially flat (the difference in height position between the outer edge and the inner edge is extremely high). The difference in height position between the peripheral edge and the center of the workpiece holding surface is also smaller than that of the holder of the comparative example.

  In the holder of the present embodiment, the difference in height position between the periphery and the center of the workpiece holding surface is about 0.5% of the passing (diameter) of the workpiece holding surface, and the outer edge of the frame member The difference in height position between the inner edge and the inner edge is substantially zero.

  Without being limited to the above-described embodiment of the present invention, various changes and modifications can be made within the scope of the technical idea described in the claims.

  Moreover, the polishing process of the silicon wafer using the holder of an Example and a comparative example was performed on the following grinding | polishing conditions, and the performance of the holder was evaluated with the polishing rate. The polishing rate is one of the numerical values indicating the polishing efficiency when an object to be polished is polished with a polishing pad. This time, the polishing rate was calculated from the polishing area and specific gravity of the polishing object per minute.

Polishing conditions Polishing machine used: Fujikoshi MCP-150X
Polishing pad: Fujibo Ehime Co., # 27
Rotation speed: (Surface plate) 60r / m (Top ring) 50r / m
Polishing pressure: 100 g / m ²
Swing width: 10mm (200mm from the swing center value)
Swing movement: 1 mm / min
Abrasive: Granzox 3900RS manufactured by Fujimi Incorporated
(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 expressed 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, the surface accuracy of the holder due to distortion of the frame material is lowered, and it is assumed that the polishing rate is lowered by the 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 greatly improved to 1.1 with respect to the polishing rate 1 of the holder of the comparative example, and it is estimated that the surface accuracy is improved.

  In addition, while moving the laser measuring device L so as to traverse the 500 mm square 700 μm glass epoxy resin plate before baking processing in a linear direction, the height position of the surface of the resin plate is continuously measured by the laser measuring device L. It was measured. As a result, convex and concave warpage of about 1 to 4 mm was observed, but in the resin plate after the baking treatment, warpage of 0.5 mm or less was suppressed and a flat resin plate was obtained.

1: single-side polishing machine 10: holder 12: backing material 16: frame material 16o: outer edge 16i: inner edge 18: polishing object holding surface 18e: peripheral edge 18c: central portion 18d: diameter

Claims (7)

A holder used when polishing a plate-shaped object to be polished with a polishing pad,
A backing material made of an elastic resin that has an object holding surface that contacts the back surface of the object to be polished and presses the object to be polished against the polishing pad with the object holding surface;
A thin plate-like frame member attached to the backing material so as to surround the polishing object holding surface of the backing material,
The difference in height position between the peripheral edge and the center of the workpiece holding surface is within 0.6% of the passing of the workpiece holding surface,
A holder characterized by that. 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,
The holder according to claim 1. The polishing object holding surface of the backing material has a substantially circular shape, and the passing is the diameter of the circle,
The frame member has a ring shape, and the width is a radial length of the ring;
The holder according to claim 1 or 2. The Shore A hardness of the backing material is 50-90,
The holder according to any one of claims 1 to 3. The compression ratio of the backing material is 3 to 30%.
The holder according to any one of claims 1 to 4. The frame material is a glass epoxy resin,
The holder according to any one of claims 1 to 5. A method of manufacturing a holder used when a plate-like object to be polished is polished with a polishing pad,
Laminating a plate of hard resin material;
Heating while laminating the laminated hard resin material plate in the laminating direction, and raising the temperature to a predetermined temperature;
Continuing the heating for a predetermined time so as to maintain the predetermined temperature while pressing the laminated hard resin material plate in the laminating direction;
While pressing the laminated hard resin material plate in the laminating direction, stopping the heating, and allowing the laminated hard resin material plate to cool;
Cutting the plate of the hard resin material that has been allowed to cool into a predetermined shape to form a frame material;
A polishing object holding surface of an elastic resin backing material that has a polishing object holding surface that abuts the frame material against the back surface of the polishing object and presses the polishing object against a polishing pad by the polishing object holding surface. A step of attaching to,
A method for manufacturing a holder.

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