JP5436959B2 - Workpiece holding material manufacturing method - Google Patents

Description

The present invention relates to the production how the workpiece holding member for holding a workpiece to processing such as polishing is performed.

  Polishing of a workpiece such as a semiconductor wafer or LCD glass is performed as follows, for example. That is, as shown in FIG. 14, 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 using a frame-shaped template 14 that prevents the position of the back 10 from shifting on the surface of the backing material 13 (see, for example, Patent Document 1).

  As the backing material 13, for example, a DMF (dimethylformamide) solution layer of urethane resin applied to a base material is wet-coagulated in water, washed in warm water, and dried with hot air. As shown in FIG. 15, for the purpose of forming the foamed layer 2 on the substrate 1 and aligning it with a required thickness, the surface 2 a of the foamed layer 2 buffed as shown in FIG. 15B is used. (See, for example, Patent Document 2).

  The surface 2a-2 of the foamed layer 2 after the buffing serves as a holding surface for adsorbing and holding the workpiece. However, the buffing does not provide a sufficiently smooth surface. Adsorption holding power was insufficient.

  For this reason, as shown in FIG. 16A, without buffing the surface 2a of the foam layer 2 formed on the base material 1, as shown in FIG. 16 is peeled off, the surface 2a is pressed against the flat pressure roller 7 as shown in FIG. 16C, and the back surface 2b side of the foam layer 2 is buffed as shown in FIG. As shown in FIG. 16 (e), there is a backing material which is adhered again to the double-sided tape 8 or the like (for example, see Patent Document 3).

JP 09-32001 A Japanese Patent No. 3187769 JP 2006-62058 A

  In such a backing material, the surface 2a of the foamed layer 2 that has not been buffed is used as a retaining surface for adsorbing and holding the workpiece, so that the surface 2a of the foamed layer 2 is adsorbed and retained as compared with the conventional example in which buffing is performed. Although the force is improved, the smoothness of the surface of the foam layer is not always sufficient due to variations in foaming.

  Also, as shown in FIG. 16C, in order to buff the back surface 2b of the foam layer 2, buff powder remains in the holes 16 in which the bubbles 15 are opened, and the foam layer 2 is compressed and deformed. There is also a problem in that the quality of the workpiece is deteriorated due to a partial difference in compression deformation rate, and the buffing powder is present at the bonding interface with the double-sided tape 8 to reduce the adhesive force.

  Furthermore, such a backing material has a large number of bubbles (pores) due to foaming, and the polishing liquid permeates from the surface (holding surface) that holds the workpiece when polishing the workpiece. In some cases, the flatness of the workpiece is deteriorated, or the adhesive strength with the base material or the double-sided tape on the back surface side is weakened, and the workpiece is peeled off from the base material or the double-sided tape.

  In addition, urethane foam by wet coagulation has many air bubbles on the surface, so it is easy to break due to cracks from the surface, and the workpiece holding material may be damaged when the workpiece is detached. .

The present invention has been made in view of the above-described points, and enhances the holding force of the workpiece holding material that holds the workpiece, eliminates the need for buffing, and further from the front and back surfaces. with the penetration of moisture, such as the polishing liquid can be suppressed, and an object thereof is to provide a manufacturing how the workpiece holding member having an increased strength of the front and back surfaces.

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

  The manufacturing method of the workpiece holding material of the present invention includes a foam layer forming step in which a resin solution is applied to a base material and wet-solidified to form a foam layer, and the base material on which the foam layer is formed. It includes a heating and pressing step of heating and pressurizing with a smooth smooth member and a smoothing member peeling step of peeling the smoothing member from the base material on which the foam layer is formed.

  The smooth member should just be smoother than the surface of the foam layer formed at least by a foam layer formation process.

  In the heating and pressing step, smooth members may be overlapped on both sides of the base material on which the foam layer is formed and simultaneously heated and pressurized, or after smooth members are stacked on one side and heated and pressed, A smooth member may be stacked on the surface and heated and pressed.

  According to the present invention, the both sides of the base material on which the foam layer is formed are sandwiched between smooth smooth members and heated and pressurized, and then the smooth member is peeled off. The surface becomes smoother than that of the conventional example, and the suction holding force for holding the workpiece is improved. In addition, since neither the front surface nor the back surface of the foam layer is subjected to buffing, buff powder does not remain in the hole formed by opening bubbles (pores). Further, since a smooth and dense layer that is crushed by heat and pressure is formed on the surface of the foamed layer, the penetration of the polishing liquid during the polishing process is prevented by the dense layer on the surface. That is, the flatness of the workpiece can be deteriorated, and the foamed layer can be prevented from peeling from the base material or the double-sided tape.

  Further, the dense layer on the surface of the foam layer increases the strength of the surface and makes it difficult to break.

  In a preferred embodiment, prior to the heating and pressurizing step, a base material peeling step of peeling the base material from the foamed layer is included, and in the heating and pressurizing step, the foamed layer from which the base material has been peeled off, It is heated and pressed between the smooth members.

  In the foam layer forming step, the foam layer shrinks slightly during wet foaming, whereas the base material made of a resin film or the like does not shrink, so that the foam layer is distorted. This distortion appears as a streak on the surface of the foam layer that holds the object to be polished. For example, in low-pressure polishing of 2 psi or less, the streak cannot be crushed, which may affect the polished surface. is there. In this embodiment, since the base material is peeled from the foamed layer, the strain of the foamed layer is released, so that the above-described problems caused by the strain do not occur.

  Furthermore, in this embodiment, since not only the surface of the foam layer but also the back surface is formed by a heat and pressure, a smooth and dense layer that is crushed is formed. It will be blocked by the dense layers on the front and back surfaces, and the flatness of the workpiece can be deteriorated, and the foamed layer can be prevented from peeling off from the substrate or the double-sided tape. In addition, the dense layers on the front and back surfaces of the foam layer increase the strength of the front and back surfaces and make it difficult to break.

  In one embodiment, the smooth member is in the form of a film or a sheet, and includes a step of attaching a double-sided tape to one side of the foam layer from which the smooth member has been peeled off in the smooth member peeling step.

  According to this embodiment, a double-sided tape can be applied with one side of the foam layer as the back surface, and the surface of the foam layer can be used as a holding surface for holding the workpiece holding material.

  In another embodiment, in the heating and pressurizing step, the base material on which the foam layer is formed or the foam layer is sandwiched between the smooth members, and at least one is passed between two rolls that are heat rolls. It is. The temperature of the heat roll is preferably 70 ° C. to 200 ° C. at which the smooth member does not melt.

  According to this embodiment, by passing between two rolls, it can be easily heated and pressurized, and by selecting conditions such as the temperature of the heat roll, the passing speed and the gap between the rolls, Properties such as thickness can be adjusted.

  In a preferred embodiment, the resin solution is a urethane resin solution, and the base material and the smooth member are resin films.

  According to the method for manufacturing a workpiece holding material of the present invention, the substrate on which the foam layer is formed is sandwiched between the smooth members, heated and pressurized, and then the smooth member is peeled off. The surface of the foam layer that becomes the surface is smoother than that of the conventional example, and the suction holding force for holding the workpiece is improved. In addition, since neither the front surface nor the back surface of the foam layer is subjected to buffing, buff powder does not remain in the hole formed by opening bubbles (pores).

  Further, since a smooth and dense layer is formed on the surface of the foam layer, the penetration of the polishing liquid during the polishing process is prevented by the dense layer on the surface, and the flatness of the work piece It is possible to prevent the foam layer from peeling off from the double-sided tape.

  In addition, since the surface of the foam layer is a dense layer in which bubbles are crushed, the strength of the surface is increased and it is difficult to break.

It is a figure which shows the manufacturing process of the workpiece holding material which concerns on one embodiment of this invention. It is a figure which shows the heating-pressing process by a heat roll. It is a scanning electron micrograph of the surface side 500 times of a comparative example. It is a scanning electron micrograph of the surface side 500 times of an Example. It is the scanning electron micrograph of the surface side 2000 times of a comparative example. It is the scanning electron micrograph of the surface side 2000 times of an Example. It is a scanning electron micrograph of the back surface 1000 times of a comparative example. It is a scanning electron micrograph of the back surface 1000 times of an Example. It is a figure which shows the waviness curve of the surface of a comparative example. It is a figure which shows the waviness curve of the surface of an Example. It is a figure which shows the waviness curve of the surface of another comparative example. It is a figure which shows the waviness curve of the surface of another Example. It is a figure which shows the manufacturing process of the workpiece holding material which concerns on other embodiment of this invention. It is a schematic block diagram of a grinding | polishing apparatus. It is a figure which shows the manufacturing process of a prior art example. It is a figure which shows the manufacturing process of another prior art example.

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

  FIG. 1 is a diagram illustrating a method for manufacturing a workpiece holding material according to an embodiment of the present invention.

  In the method for manufacturing a workpiece holding material of this embodiment, first, a DMF (dimethylformamide) solution of a urethane resin is applied onto a base material 1 such as a PET film, and the wet coagulation method is used to perform FIG. As shown in FIG. 2, a porous foam layer 2 having a large number of bubbles such as teardrop-shaped bubbles is formed on the substrate 1. The foam layer 2 is peeled from the substrate 1 as shown in FIG.

  In the step of forming the foamed layer 2 by the wet coagulation method, the foamed layer contracts slightly during the wet foaming, whereas the base material 1 made of PET film or the like does not contract, so that the foamed layer 2 is distorted. This distortion appears as a streak on the surface of the foamed layer 2 that holds the object to be polished. For example, in low-pressure polishing of 2 psi or less, the streak cannot be crushed, which affects the polished surface. However, in this embodiment, since the base material 1 is peeled from the foam layer 2, the strain of the foam layer 2 is released, thereby causing the above-described problems caused by the strain. It does not occur.

  Next, as shown in FIG. 1C, the front and back surfaces 2a and 2b of the foam layer 2 are overlapped with a resin film 3 such as a PET film as a smooth member, and passed between two heat rolls. As shown in FIG. 1 (d), they are heated and pressurized to be integrated.

  Thereafter, the resin film 3 on the front and back surfaces is peeled off as shown in FIG. 1 (e), the double-sided tape 4 is attached to the back surface 2b-1, and the surface 2a-1 is processed as shown in FIG. 1 (f). A workpiece holding material having a holding surface is obtained.

  In the workpiece holding material of this embodiment, since the resin film 3 is superimposed on the foam layer 2 and heated and pressurized by a heat roll, the front surface 2a-1 and the back surface 2b-1 of the foam layer 2 are formed on the base material 1. Compared to the front surface 2a and back surface 2b of the foamed layer 2 formed by applying a resin solution and wet coagulating, it is smooth. In particular, the surface 2a-1 of the foam layer 2 serving as a holding surface for holding the workpiece is a smooth surface having a maximum value (Wcmax) of the waviness curve element within 3 μm, as will be described later.

  Further, since the back surface 2b-1 of the foam layer 2 is not buffed, no teardrop-shaped bubbles are opened as shown in FIG.

  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 the manufacturing method of the workpiece holding material of this embodiment, the resin film is heated and pressed with a heat roll with the smooth resin film 3 sandwiched between the front and back surfaces 2a and 2b of the foam layer 2 peeled off from the substrate 1. 3 is peeled off, the front and back surfaces 2a-1 and 2b-1 of the foam layer 2 are smooth, and therefore, the adsorption holding force of the surface 2a-1 of the foam layer 2 serving as a holding surface for holding the workpiece holding material. Will improve.

  Further, the front and back surfaces 2a-1 and 2b-1 of the foam layer 2 are formed with smooth and dense layers in which bubbles (pores) are crushed by heat and pressure. The penetration of the liquid is prevented by the dense layers on the front and back surfaces. Thereby, the flatness of the workpiece can be deteriorated, and the foam layer 2 can be prevented from being peeled off from the double-sided tape 4. Further, the front and back surfaces 2a-1 and 2b-1 are dense layers formed by crushing bubbles, so that the strength is increased and the material is not easily broken. It can be prevented from being damaged.

  The surface 2a-1 of the foam layer 2 was evaluated as follows. That is, as shown in FIG. 1 (c), the foamed layer 2 having a thickness of 1.2 mm by overlapping a smooth resin film 3 on both the front and back surfaces 2a and 2b has a gap of 1.0 mm as shown in FIG. Then, it passes between the upper and lower heat rolls 5 and 6 at 150 ° C. at 1.0 m / min, and then the surface from which the resin film 3 is peeled, that is, the foam layer 2 of the embodiment shown in FIG. The surface 2a-1 was observed with a scanning electron microscope (SEM), and the surface waviness was measured with a measuring device described later. Moreover, the back surface which peeled the resin film 3, ie, the back surface 2b-1 shown by FIG.1 (e), was observed with the scanning electron microscope (SEM).

  On the other hand, as a comparative example, the surface 2a and the back surface 2b of the foamed layer 2 peeled from the base material 1 shown in FIG. Similarly, the surface 2a and the back surface 2b of the foam layer 2 were observed with a scanning electron microscope (SEM), and the surface waviness was measured.

  3 and 4 are SEM photographs of the edge portion of the surface of the comparative example and the example with a magnification of 500 times, and FIGS. 5 and 6 are SEM images of the edge portion of the surface of the comparative example and the example with a magnification of 2000 times. In these drawings, the edge portion of the surface is an SEM image so that the surface and side surfaces can be observed.

  7 and 8 are SEM photographs of the back surface of the comparative example and the example with a magnification of 1000 times.

  After the resin film 3 is stacked and the heat rolls 5 and 6 are passed, the surface of the foamed layer of the example shown in FIGS. 4 and 6 where the resin film 3 is peeled off is the foam of the comparative example of FIGS. 3 and 5. Compared with the surface of the layer, the surface is smooth, small bubbles (pores) are crushed, and a dense layer is formed.

  As described above, the surface of the foamed layer that serves as a holding surface for holding the workpiece holding material is a smooth surface, so that the adsorption holding force for holding the workpiece holding material is improved.

  Further, since neither the front surface nor the back surface of the foam layer needs to be buffed, the buff powder does not remain in the pores of the open bubbles.

  Further, small bubbles (pores) are also crushed on the back surface of the foam layer of the embodiment of FIG. 8, and a dense layer is formed as compared with the comparative example of FIG.

  As described above, the front and back surfaces of the foam layer are both smoother and denser than conventional ones. When holding and polishing the workpiece holding material, the penetration of the polishing solution It is suppressed by the dense layer, and the flatness of the workpiece can be deteriorated, and the foamed layer can be prevented from being peeled off from the double-sided tape due to the penetration of the polishing liquid.

Next, the measurement results of the surface waviness of the above examples and comparative examples are shown.
The measurement conditions are as shown in Table 1 below.

  FIG. 9 shows the filtered waviness curve of the comparative example, and FIG. 10 shows the filtered waviness curve of the example.

  In addition, Wa (arithmetic mean waviness), Wcmax (maximum value of the waviness curve element height), and Wfpd (straightness about a certain reference length in the filtered centerline waviness curve) of the example and the comparative example, Table 2 shows the measurement results of the maximum value within the range of the evaluation length.

  As shown in FIGS. 9 and 10 and Table 2, it can be seen that the undulation is reduced on the surface of the foamed layer of the example as compared with the comparative example.

  As shown in Table 2, the maximum height Wcmax of the waviness curve element of the example is 2.8113 μm and within 3 μm, whereas the maximum height of the waviness curve element of the comparative example is The value Wcmax is 5.9305 μm.

  Therefore, according to the workpiece holding material of the embodiment, the flatness of the workpiece can be improved.

    Furthermore, the compressibility of the workpiece holding material in which the double-sided tape was attached to the back surface of the foamed layer of the example was measured.

  The compression rate was calculated by the following equation by measuring the thickness T1 when an initial load was applied to the sample for 1 minute, and then measuring the thickness T2 when the second load was applied for 1 minute.

Compression rate (%) = [(T1-T2) / T1] × 100
The compression ratio of the workpiece holding material of the example was 35.1%.

  This compression rate is preferably 20% to 60%.

  Further, different examples and comparative examples were manufactured using low modulus foamed polyurethane resins having different compositions from the above examples and comparative examples, and surface waviness was measured in the same manner.

  FIG. 11 shows the filtering undulation curve of the comparative example, and FIG. 12 shows the filtering undulation curve of the example.

  Table 3 shows the measurement results of Wa, Wcmax, and Wfpd of the example and the comparative example.

  As shown in FIGS. 11 and 12 and Table 3, it can be seen that the swell is reduced even with polyurethane foam resins having different compositions.

  As shown in Table 3, the maximum value Wcmax of the waviness curve element of the example is 2.058 μm and within 3 μm, whereas the maximum height of the waviness curve element of the comparative example is The value Wcmax is 3.3328 μm.

  FIG. 13 is a diagram showing a method for manufacturing a workpiece holding material according to another embodiment of the present invention, and the same reference numerals are given to the portions corresponding to FIG. 1 described above.

  In the method for manufacturing a workpiece holding material of this embodiment, first, a DMF (dimethylformamide) solution of a urethane resin is applied onto a base material 1 such as a PET film, and the wet coagulation method is used to perform FIG. As shown in FIG. 2, a porous foam layer 2 having a large number of bubbles such as teardrop-shaped bubbles is formed on the substrate 1.

  Next, as shown in FIG. 13B, the base material 1 on which the foam layer 2 is formed is sandwiched between resin films 3 and passed between two heat rolls, as shown in FIG. 13C. As shown in FIG. Thereafter, the resin films 3 on the front and back surfaces are peeled off as shown in FIG. 13D to obtain a workpiece holding material having the surface 2a-1 as the holding surface of the workpiece.

  In the workpiece holding material of this embodiment, since the resin film 3 is superimposed on the surface of the foam layer 2 and heated and pressurized by a heat roll, the surface 2 a-1 of the foam layer 2 has a resin solution applied to the substrate 1. It is smoother than the surface 2a of the foam layer 2 that is applied and wet-solidified.

  Other configurations are the same as those of the above-described embodiment.

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

DESCRIPTION OF SYMBOLS 1 Base material 2 Foam layer 3 Resin film 4 Double-sided tape 5,6 Heat roll

Claims (7)

A foam layer forming step in which a resin solution is applied to a substrate and wet solidified to form a foam layer;
A heating and pressurizing step of heating and pressurizing the base material on which the foam layer is formed between smooth smooth members;
A smooth member peeling step for peeling the smooth member from the base material on which the foam layer is formed;
A method for producing a workpiece holding material, comprising: Prior to the heating and pressing step, including a substrate peeling step for peeling the substrate from the foam layer,
The manufacturing method of the workpiece holding material of Claim 1 which heats and presses the said foaming layer from which the said base material peeled by the said smooth member in the said heat pressurization process. The smooth member is a film or a sheet,
The manufacturing method of the workpiece holding material of Claim 2 including the process of affixing a double-sided tape on the single side | surface of the said foaming layer which peeled the said smooth member at the said smooth member peeling process.   4. The method according to claim 1, wherein in the heating and pressurizing step, the base material on which the foam layer is formed or the foam layer is sandwiched between the smooth members, and at least one of the two rolls is a heat roll. A method for producing a workpiece holding material according to claim 1.   The method for manufacturing a workpiece holding material according to claim 4, wherein a temperature of the heat roll is 70 ° C. to 200 ° C.   The method for producing a workpiece holding material according to any one of claims 1 to 5, wherein the resin solution is a urethane resin solution.   The said base material and the said smooth member are resin films, The manufacturing method of the workpiece holding material as described in any one of Claim 1 thru | or 6.