JP4943766B2 - Workpiece holding material and method for manufacturing the same - Google Patents

Description

  The present invention relates to a workpiece holding material that holds a workpiece to be processed such as polishing and a method for manufacturing the same.

  Polishing of a workpiece such as a semiconductor wafer or LCD glass is performed as follows, for example. That is, as shown in FIG. 9, the workpiece 10 to be polished is held on the upper surface plate 9 of the surface plate facing the upper and lower sides of the polishing apparatus, and the polishing pad 12 is held on the lower surface plate 11. By pasting the surface of the workpiece 10 against the polishing pad 12 and supplying a polishing liquid containing abrasive grains between the two surface plates, the surface plates 9 and 11 are relatively rotated as indicated by arrows. Done.

  Conventionally, the workpiece 10 is fixed to the upper surface plate 9 and surrounds the backing material 13 as a workpiece holding material that sucks and holds the back surface of the workpiece 10 and the outer periphery of the workpiece 10. 10 is held on the upper surface plate 9 by using a frame-shaped template 14 that prevents displacement of the backing material on the surface of the backing material (see, for example, Patent Document 1).

  However, in such a holding method using the template 14, a gap is generated between the workpiece 10 and the template 14 due to a dimensional tolerance of the template 14 and the workpiece 10. There is a problem that the position of the workpiece 10 is shifted and repeatedly contacts the template 14 to cause cracks or damage to the template 14, or the workpiece 10 is dropped from the template 14 and deteriorates the quality. Since the template 14 is required, there is a problem that the cost is increased accordingly.

As the backing material 13, for example, a DMF (dimethylformamide) solution layer of urethane resin applied to a base material is wet-solidified in water, washed in warm water, dried with hot air to form a foam layer, For the purpose of adjusting to a required thickness, the surface of the foam layer is buffed. The surface of the foamed layer serves as a holding surface for adsorbing and holding the workpiece. However, the buffing process does not provide a sufficiently smooth surface, so that the adsorption holding force of the workpiece is insufficient. It was.
JP 09-32001 A

  For this reason, as shown in the schematic cross-sectional view of FIG. 10A, the foam layer 31 is peeled off from the base material 30 without buffing the surface 31a of the foam layer 31 formed on the base material 30. After buffing the back surface 31b side of the foam layer 31 as shown in FIG. 2B, there is a backing material that is adhered again to the double-sided tape 32 or the like as shown in FIG. In such a backing material, the surface 31a of the foamed layer 31 that has not been buffed is used as a holding surface that sucks and holds the workpiece. Although improved, there is a drawback that the smoothness of the surface of the foam layer is not always sufficient due to variations in foaming.

  Furthermore, the workpiece holding material of the conventional example has a drawback in that it is not easy to adjust the compression ratio for absorbing warpage or undulation of the workpiece during polishing.

  The present invention has been made in view of the problems as described above, and can increase the holding force of a workpiece holding material that holds the workpiece and can absorb the waviness of the workpiece. It is an object of the present invention to provide a holding material and a manufacturing method thereof.

  In order to achieve the above object, the present invention is configured as follows.

In the workpiece holding material of the present invention, the first and second foamed layers respectively formed by the wet coagulation method in which a resin solution is applied on a base material and wet coagulated are provided in the thickness direction. Each of which has a teardrop-shaped bubble that is tapered, and the teardrop-shaped bubble of the second foam layer is smaller than the teardrop-shaped bubble of the first foam layer, and The first and second foam layers are laminated via an adhesive layer with the surfaces of the first and second surfaces facing each other. The back surface of the second foamed layer from which the substrate has been peeled is used as a holding surface for holding the workpiece.

  The adhesive layer includes an adhesive layer.

  According to the present invention, the base material is peeled from the back surface of the second foam layer formed by the wet coagulation method, and the back surface of the second foam layer, which is the same smooth surface as the base material, is removed from the work piece. Since the holding surface for holding is used, the suction force for holding the workpiece is improved, and the processing accuracy of the workpiece can be increased.

  Moreover, since it has a two-layer configuration of the first foam layer and the second foam layer, it is easier to set the compression ratio required to absorb the waviness of the workpiece as compared with the case of one layer. Become.

  In one embodiment of the present invention, the first foamed layer has air bubbles open on the surface of the foamed layer.

  According to this embodiment, bubbles on the surface of the foam layer can be opened to obtain an appropriate cushioning property.

  In another embodiment of the present invention, the compression rate is 20% or more and 50% or less.

  According to this embodiment, since the compression rate is 20% or more and 50% or less, the swell of the workpiece can be absorbed.

  In another embodiment of the present invention, the first foam layer has a compression rate of 30% or more and 60% or less, which is higher than that of the second foam layer.

  According to this embodiment, the workpiece can be adsorbed and held by the second foam layer while the cushioning property is ensured by the first foam layer having a higher compressibility than the second foam layer.

  In one embodiment of the present invention, the ratio of the thickness of the first foam layer and the second foam layer is 1: 1 to 20: 1.

  According to this embodiment, the first foam layer having a higher compression rate than the second foam layer can be made thicker than the second foam layer to ensure sufficient cushioning properties.

In the method for manufacturing a workpiece holding material of the present invention, a resin solution is applied to a first substrate, wet-coagulated, and in the thickness direction, a teardrop-like shape in which one surface side is tapered. The step of forming the first foamed layer having air bubbles , the second base material is coated with a resin solution, wet-solidified , and one surface side is tapered with respect to the thickness direction. A teardrop-shaped bubble that is smaller than the teardrop-shaped bubble of the first foam layer and has a teardrop-shaped bubble that is biased to the one surface side with respect to the thickness direction . forming a second foam layer, said first, a surface that is the one surface of each of the second foam layer laminating through an adhesive layer by face each other, of the second foam layer Peeling the second base material on the back surface and using the back surface of the second foam layer as a holding surface for holding the workpiece. .

  According to the present invention, the first and second foamed layers are formed by the wet coagulation method, the surfaces of the foamed layers are opposed to each other and laminated via the adhesive layer, and the base material on the back surface of the second foamed layer And the back surface of the second foam layer, which is a smooth surface similar to the base material, is used as a holding surface for holding the workpiece, so that the adsorption force for holding the workpiece is improved, The processing accuracy of the workpiece can be increased.

  Moreover, since it has a two-layer configuration of the first foam layer and the second foam layer, it is easier to set the compression ratio required to absorb the waviness of the workpiece as compared with the case of one layer. Become.

  In a preferred embodiment of the present invention, the resin solution is a urethane resin solution, and the second base material is a resin film.

  In another embodiment of the present invention, a step of grinding the surface of the first foam layer is provided before the step of laminating.

  According to this embodiment, it is possible to obtain appropriate cushioning properties by opening the bubbles on the surface of the foam layer by grinding.

  According to the present invention, since the back surface of the smooth second foamed layer peeled off from the base material is used as the holding surface for holding the workpiece, the adsorption force can be improved.

  Moreover, since it has a two-layer structure of the first foam layer and the second foam layer, by selecting the compression rate, it is possible to perform polishing or the like by absorbing the swell of the workpiece.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a schematic cross-sectional view of a workpiece holding material according to an embodiment of the present invention.

  The workpiece holding material 1 of this embodiment includes a first foam layer 3 formed on a first base 2 by a wet coagulation method, and an adhesive layer 4 on the surface of the first foam layer 3. The first and second foamed layers 3 and 5 are arranged via the adhesive layer 4 with the surfaces of the foamed layers 3 and 5 facing each other. Are stacked.

  The second foam layer 5 is formed to have a smaller thickness or a lower compression rate than the first foam layer 3.

  The compression ratio of the first foam layer 3 is 30% or more and 60% or less.

  The thickness ratio of the first foam layer 3 and the second foam layer 5 is preferably 1: 1 to 20: 1, more preferably 2: 1 to 15: 1. More preferably, it is 3: 1 to 6: 1. The total thickness is preferably about 0.8 to 1.5 mm, for example.

  The ratio of the thickness of the first foam layer 3 and the second foam layer 5 can be arbitrarily set within the above range, but in order to absorb the waviness of the workpiece, the compression ratio is: It is preferably 20% or more and 50% or less.

  FIG. 2 is a diagram illustrating an example of a manufacturing process of the workpiece holding material 1 of this embodiment.

  For example, a DMF (dimethylformamide) solution of urethane resin is applied on the first base material 2 such as a PET film, and the first foamed layer 3 is wet-solidified as shown in FIG. Then, foam molding is performed on the substrate 2.

Next, as shown in FIG. 2B, the surface of the first foam layer 3 is buffed , and the surface 3a side, which is one surface, is tapered with respect to the thickness direction (vertical direction in FIG. 2). The teardrop-shaped bubble 6 is opened.

On the other hand, the second foamed layer 5 is coated with a DMF (dimethylformamide) solution of urethane resin on the second substrate 7 such as a PET film, and then wet-solidified as shown in FIG. Then, foam molding is performed on the base material 7. The second foamed layer 5 is tapered on the surface 5a side as one surface with respect to the thickness direction (vertical direction in FIG. 2), and the teardrop-shaped air bubbles 6 of the first foamed layer 6 are formed. Smaller teardrop-shaped bubbles.

  Next, as shown in FIG. 2 (d), the second foam layer 5 is laminated on the surface 3a of the first foam layer 3 via the adhesive layer 4 with the surface 5a of the foam layer facing down. To do.

  Next, the work piece holding material 1 of FIG. 1 is obtained by peeling off the second base material 7 on the back surface side of the second foam layer 5.

  The substrates 2 and 7 are preferably resin films such as PET (polyethylene terephthalate), but may be those obtained by impregnating a nonwoven fabric with a resin solution such as a urethane resin solution and wet coagulating it.

  As the urethane resin for forming the foamed layer 2, a urethane resin such as polyester, polyether, or polycarbonate can be used, and different types of urethane resins may be blended.

  As the water-soluble organic solvent for dissolving the urethane resin, for example, a solvent such as dimethyl sulfoxide, tetrahydrofuran, dimethylacetamide or the like can be used in addition to the above-mentioned dimethylformamide.

  In this workpiece holding material 1, as shown in FIGS. 2D and 2E, the back surface 5b of the second foamed layer 5 from which the base material 7 such as a PET film is peeled off, that is, the base material such as a PET film. A smooth back surface similar to 7 is used as a holding surface for holding the workpiece.

  Thus, since the smooth surface like the surface of the PET film is used as the holding surface of the workpiece, the adsorption force for adsorbing the workpiece is improved.

  3 and FIG. 4, after buffing the back side of the foam layer peeled from the base material without buffing the surface of the work piece holding material of the example according to this embodiment and the foam layer, both surfaces FIG. 3 shows the results of measuring the suction force with the workpiece holding material of the conventional example that is again bonded to the tape or the like. FIG. 3 shows the suction force in the vertical direction, and FIG. 4 shows the suction force in the horizontal direction. Yes.

  Each measurement was performed as follows.

That is, as shown in FIG. 5, the vertical attractive force is measured by using a cylindrical glass 20 having a surface accuracy of 50 mm in diameter and a 75 mm diameter embodiment or conventional example fixed to a surface plate 21. A load of 150 g / cm ² is adsorbed to the object holding material 22 over 10 seconds. Thereafter, the film is pulled in the vertical direction at a constant speed of 200 mm / min, and the peel strength when the glass-workpiece holding material peels is measured by an autograph.

  In the wet state, 10 ml of pure water is dropped on the surface of the workpiece holding material, the surface of the workpiece holding material is wiped to remove water, and then the glass is adsorbed as described above.

  In addition, as shown in FIG. 6, in the measurement of the suction force in the horizontal direction, the columnar glass 20 is attracted to the workpiece holding material 22 under the load as described above. Thereafter, the glass 20 is pulled in the horizontal direction through the pulley 23 at a constant speed of 200 mm / min, and the peel strength when the glass 20 starts to move in the horizontal direction is measured by an autograph. In the wet state, as in the case of the vertical direction, after dropping pure water, the surface of the workpiece holding material is wiped to remove water and adsorb the glass.

As shown in FIG. 3, it can be seen that the adsorption force in the vertical direction is larger in the example than in the conventional example in both the dry state and the wet state.
In particular, it can be seen that in the dry state, the adsorption force of the example is significantly higher than that of the conventional example.

  Moreover, as shown in FIG. 4, it can be seen that the horizontal suction force is greater in the example than in the conventional example except for the initial wet state.

  Table 1 shows the physical properties of the workpiece holding material of the example and the workpiece holding material of the conventional example.

In Table 1, the thickness (Thickness) is measured at a measurement load of 100 gf / cm ² , and the compression rate (Compressibility) and the recovery rate (Recovery) are 300 gf / cm ² for the initial load and 1800 gf / cm for the second load. Measured in ² .
Here, the compression rate and the recovery rate were measured and calculated as follows.

  That is, the thickness T1 when the initial load is applied to the sample for 1 minute is measured, and then the thickness T2 when the second load is applied for 1 minute is measured. Next, the sample is left for one minute with all the load removed. Again, the thickness T3 when the initial load is applied for 1 minute is measured.

  From these measured values T1, T2, and T3, the compression rate and the recovery rate were calculated by the following equations.

Compression rate (%) = {(T1-T2) / T1} × 100
Recovery rate (%) = {(T3-T2) / (T1-T2)} × 100
7 and 8 show electron microscope (SEM) photographs of cross sections of the workpiece holding material of the example and the workpiece holding material of the conventional example.

  The present invention is useful for polishing semiconductor wafers and precision glass substrates.

It is sectional drawing of the workpiece holding material which concerns on one embodiment of this invention. It is a figure which shows the manufacturing process of the workpiece holding material of FIG. It is a figure which shows the measurement result of the adsorption | suction force of the orthogonal | vertical direction of an Example and a prior art example. It is a figure which shows the measurement result of the adsorption | suction force of the horizontal direction of an Example and a prior art example. It is a figure for demonstrating the measuring method of the adsorption | suction force of a perpendicular direction. It is a figure for demonstrating the measuring method of the adsorption | suction power of a horizontal direction. It is a cross-sectional electron micrograph of an Example. It is a cross-sectional electron micrograph of a conventional example. It is a schematic block diagram of a grinding | polishing apparatus. It is a figure which shows the manufacture procedure of a prior art example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Workpiece holding material 2 Base material 3,5 1st, 2nd foam layer 4 Adhesive layer

Claims (9)

Each of the first and second foamed layers formed by wet coagulation by applying a resin solution on a base material and wet coagulating is in the form of teardrops with one side tapered toward the thickness direction. The tear-drop-like bubbles of the second foam layer are smaller than the tear-drop-like bubbles of the first foam layer, and the one of the ones with respect to the thickness direction The first and second foamed layers are laminated via an adhesive layer with the surfaces of the first and second surfaces facing each other, and the substrate is peeled off. A workpiece holding material, wherein the back surface of the foam layer is a holding surface for holding the workpiece.   The workpiece holding material according to claim 1, wherein the first foamed layer has air bubbles open on the surface of the foamed layer.   The workpiece holding material according to claim 1 or 2, wherein the compression ratio is 20% or more and 50% or less.   The first foamed layer has a compression rate of 30% or more and 60% or less, and a higher compression rate than the second foamed layer. Workpiece holding material.   The workpiece holding material according to any one of claims 1 to 4, wherein a thickness ratio between the first foam layer and the second foam layer is 1: 1 to 20: 1. Applying a resin solution to the first substrate, wet coagulating , and forming a first foam layer having teardrop-shaped air bubbles whose one side is tapered in the thickness direction; ,
A resin solution is applied to the second base material, wet-coagulated , and one surface side is tapered in the thickness direction, and is smaller than the teardrop-shaped bubbles of the first foam layer. Forming a second foamed layer having teardrop-shaped bubbles that are teardrop-shaped bubbles and are present on the one surface side in a biased manner with respect to the thickness direction ;
A step of laminating the surfaces of the first and second foamed layers facing each other through an adhesive layer;
Peeling the second base material on the back surface of the second foam layer, and making the back surface of the second foam layer a holding surface for holding a workpiece;
A method for producing a workpiece holding material, comprising:   The method for producing a workpiece holding material according to claim 6, wherein the resin solution is a urethane resin solution.   The method for manufacturing a workpiece holding material according to claim 6 or 7, wherein the second base material is a resin film.   The manufacturing method of the workpiece holding material of any one of Claims 6-8 provided with the process of grinding the surface of a said 1st foam layer before the said process to laminate | stack.