JP4997859B2 - Backing pad, workpiece polishing apparatus and workpiece polishing method - Google Patents

Description

  The present invention mainly relates to a workpiece polishing technique, and more particularly to a backing pad that maintains a high frictional force between a workpiece and a backing pad during a polishing process, and a polishing apparatus and a polishing method using the backing pad.

When manufacturing a semiconductor wafer such as a silicon wafer, one of important processes is a polishing process for improving the surface roughness of the wafer and increasing the flatness.
With the recent increase in accuracy of devices, semiconductor wafers used for device fabrication are required to be planarized with very high accuracy. In response to such demands, chemical mechanical polishing (CMP) is used as a technique for planarizing the surface of a semiconductor wafer.

When chemical mechanical polishing of a semiconductor wafer (hereinafter sometimes referred to as “wafer”) is performed, the surface opposite to the surface to be polished (surface to be polished) is conventionally coated with an adhesive such as wax. There is a method of attaching to and holding on a glass plate or the like.
On the other hand, as one of the so-called wax-free polishing (also called waxless polishing) methods for holding and polishing a wafer without using an adhesive such as wax, a backing pad made of a soft resin foam sheet is provided. There is a method using a holding plate.

  For example, in the polishing apparatus 38 as shown in FIG. 3, the work holding means 31 in which a backing pad 34 and a template 35 having a circular hole surrounding the work W are attached to a circular holding disk main body 32 made of ceramics or the like. The one side of the workpiece W is held in close contact with the backing pad 34 through water. Then, the polishing slurry 33 is supplied to the polishing cloth 36 affixed to the rotating surface plate 37, and the surface to be polished of the workpiece W is pressed against the polishing cloth 36 while rotating the surface plate 37 and the work holding means 31, respectively. Make contact. Thereby, the to-be-polished surface of the workpiece | work W can be finished in mirror surface shape.

As the backing pad 34 used at this time, a suede-like film produced through a process as shown in FIG. 4 is usually used.
As a method for producing this suede-like film, for example, a solution obtained by dissolving a urethane resin in a water-soluble organic solvent such as dimethylformamide (DMF) is applied to a base material 41 made of polyethylene terephthalate (PET), and this is solidified. After forming the holding film 42 having pores 43 formed with a so-called porous silver surface layer 44, which is treated with a liquid and so-called wet-solidified, which looks like a silver surface on the surface (FIG. 4A). After washing and drying, the porous silver surface layer 44 is ground to obtain a backing pad having a holding film 45 having a large number of open microvoids 46 on the surface (FIG. 4B).

  When the work is adsorbed to the backing pad, the holding film is pre-wet with water in order to use the surface tension of water, and then the work W is loaded into the template. Since the inner peripheral surface of the template for fixing the workpiece and the edge portion of the workpiece are in contact during polishing, the material of the template inner peripheral surface is at least so as not to scratch or indent the edge portion of the workpiece. A material that is softer than the workpiece is used. However, if the friction coefficient between the surface to be polished and the polishing cloth is larger than the friction coefficient between the holding film and the back surface of the workpiece during polishing, the workpiece rotates in the template, and the edge portion and the inner peripheral surface of the template However, there was a problem that the polishing slurry easily penetrated during that time, and the edge portion of the workpiece was contaminated. Further, in the subsequent cleaning process, the edge portion of the workpiece is brought into contact with the transfer hand for transfer, so that the dirt stains the transfer hand. In addition, there was a problem that the surface of the workpiece was contaminated.

  In order to solve such a problem, a technique is disclosed in which an adhesive material layer is provided on the surface of the backing pad in order to increase the coefficient of friction between the backing pad and the workpiece (see, for example, Patent Document 1). However, in such a work holding method, the adhesive layer and the back surface of the semiconductor wafer are in direct contact with each other, but the adhesive layer is not cured by a wet coagulation method as in a normal suede-like film. As a result, the water-soluble component of the adhesive material layer melts and adheres to the back surface of the semiconductor wafer. In addition, there is a problem that a part of the constituent material of the adhesive layer itself adheres to the back surface of the semiconductor wafer.

JP 2005-224888 A

  The present invention has been made in view of such a problem. A backing pad that can maintain a high frictional force between a workpiece and a backing pad during polishing of the workpiece and that hardly contaminates the workpiece during polishing. An object of the present invention is to provide a workpiece polishing apparatus and a workpiece polishing method using the same.

The present invention has been made to solve the above-described problem, and is a backing pad that holds a workpiece when the workpiece is polished, and includes at least a substrate and a water-absorbent resin laminated on the substrate. Layer and a water-repellent resin layer laminated on the water-absorbent resin layer and having a lower water absorbency than the water-absorbent resin layer. that provides backing pad, characterized in that is to hold in close contact to the surface of the water repellent resin layer by.

  With such a backing pad, it is possible to prevent an excessive water film from being formed between the workpiece and the backing pad during polishing of the workpiece, and to keep the frictional force between the workpiece and the backing pad high. Can do. As a result, the rotation of the workpiece can be suppressed and the workpiece can be reliably held on the backing pad. Therefore, contamination by the polishing slurry at the edge portion of the workpiece can be prevented. Further, when the work is transferred, water on the surface of the backing pad does not run short, so that a reduction in the suction force can be suppressed and the work is not dropped.

In this case, the water-repellent resin layer on the water-absorbent resin layer is obtained by bonding a water-repellent resin film to the water-absorbent resin layer or by applying a water-repellent resin raw material to the water-absorbent resin layer. it is not preferable in which cured.

  Thus, the water-repellent resin layer on the water-absorbent resin layer is obtained by bonding a water-repellent resin film to the water-absorbent resin layer, or a water-repellent resin material is applied to the water-absorbent resin layer and cured. If it is a thing, the backing pad which has the said structure can be produced by an easy method.

In this case, at least one of the water-absorbent resin layer and the water repellent resin layer, have preferably be one having a foam structure.

  Thus, if it is a resin layer which has a foam structure, a water | moisture content can be reliably hold | maintained in a resin layer.

In this case, the pores of the water-absorbent resin layer having a foam structure and / or water-repellent resin layer, it is not preferable part is one that is open upward.

  As described above, if a part of the pores of the water-absorbent resin layer and / or the water-repellent resin layer having a foamed structure is opened upward, the backing pad even if the resin on the surface of the backing pad is water-repellent. Adsorption force due to the surface tension of water on the surface can be ensured.

Further, at least one of the water-absorbent resin layer and the water repellent resin layer, has preferably to be made of a polyurethane resin.

  Thus, if it is a resin layer which consists of polyurethane resins, the resin layer which has a foaming structure can be formed in low cost.

Further, the present invention provides a workpiece polishing apparatus for holding a workpiece via a workpiece holding means attached to a holding plate body, and polishing the workpiece surface by sliding the workpiece against a polishing cloth. And providing a workpiece polishing apparatus characterized by comprising a backing pad for holding at least the surface opposite to the surface to be polished, wherein the backing pad is the backing pad described above. The

  With such a workpiece polishing apparatus, polishing can be performed while preventing slurry contamination at the edge portion without reliably holding the workpiece in the workpiece holding means and rotating the workpiece.

In this case, Ru can comprise a template for positioning of the workpiece on the side to be close contact with the work of the backing pad.

  As described above, when the backing pad of the present invention is used, the workpiece having the template for positioning the workpiece on the side to be in close contact with the workpiece of the backing pad in order to prevent the workpiece from coming off from a predetermined position during polishing is polished. Even in the apparatus, since the work is securely held by the backing pad, the work does not rotate and rub against the inner peripheral surface of the template, and it is possible to suppress the occurrence of dirt such as particles at the edge portion. it can.

Further, according to the present invention, there is provided a method for polishing a workpiece, using at least the workpiece polishing apparatus described above, holding one surface of the workpiece in close contact with the backing pad, and supplying an abrasive to the polishing cloth. the polishing method of the work, which comprises a step of polishing by sliding contact with the polished surface of the workpiece to the polishing cloth Ru are provided.

  As described above, with the workpiece polishing method using the workpiece polishing apparatus described above, the workpiece can be reliably held on the backing pad and polished while preventing slurry contamination of the workpiece edge portion.

  According to the backing pad of the present invention, it is possible to prevent formation of an excessive water film between the workpiece and the backing pad during the polishing of the workpiece, and to keep the friction coefficient between the workpiece and the backing pad high. Therefore, the work can be reliably held on the backing pad. Therefore, it is possible to prevent the workpiece from rotating during polishing, and it is possible to prevent the edge portion and the inner peripheral surface of the template from being rubbed and to prevent contamination. Further, when the work is transferred, water on the surface of the backing pad does not run short, so that a reduction in the suction force can be suppressed and the work is not dropped.

  Further, according to the workpiece polishing apparatus having such a backing pad, the workpiece can be reliably held and polished on the backing pad, and generation of particles or the like due to collision between the workpiece and the template can be suppressed. This makes it possible to finish the workpiece stably with few particles.

  Hereinafter, the present invention will be described in more detail, but the present invention is not limited thereto. The work to which the present invention is applied is not particularly limited and can be applied to polishing a thin plate-like work such as a semiconductor wafer including a silicon wafer, an oxide crystal, and a quartz substrate. As a specific example, a case where a silicon wafer is polished will be described below as an example.

  As described above, when the friction coefficient between the work surface (surface to be polished) and the polishing cloth is larger than the friction coefficient between the holding film and the back surface of the work during polishing, the work rotates in the template, and the edge portion There was a problem that the inner peripheral surface of the template was rubbed, and the polishing slurry easily infiltrated between them, resulting in contamination on the edge of the workpiece.

  Therefore, the present inventors have studied a method for increasing the friction coefficient between the backing pad and the back surface of the workpiece as much as possible so that the workpiece does not rotate excessively in the template during the polishing of the workpiece.

  As described above, there is an influence of water used for adsorbing the work to the backing pad as having a great influence on the friction coefficient between the work back surface and the backing pad. If the water contained in the holding film oozes out due to the load for polishing the workpiece and a water film is formed between the back surface of the workpiece and the holding film, the coefficient of friction decreases, and the workpiece rotates. It becomes easy.

Usually, a silicon wafer before polishing is cleaned with an oxidizing cleaning solution after the previous step, and a thin oxide film is formed on the surface. In the case of a silicon wafer, the contact angle of the surface of the silicon wafer after cleaning with an oxidizing cleaning liquid, for example, a so-called SC-1 cleaning liquid is hydrophilic at 0.5 ° or less, so that a water film is easily formed on the surface. . On the other hand, when washed with thin hydrofluoric acid, the contact angle of the surface is water repellency of 58 ° to 63 °, so that it is difficult to form a water film on the surface.
Therefore, when a silicon wafer is used as a workpiece, if the surface is made water-repellent and held using a conventional backing pad, a water film is unlikely to form between the workpiece and the backing pad even during the polishing process. We thought that the coefficient of friction between the backing pads could be kept high.

In the following experiment, the droplet absorption time may be measured, and the measurement method and definition are as follows. That is, a droplet of 4 μL of pure water is dropped on a backing pad for evaluation, and “PG-X” manufactured by FIBLO is used as a measuring instrument, and the contact angle after 1 second is automatically read at intervals of 50 milliseconds. The time until the contact angle became 0.5 ° or less was measured, and this time was taken as the droplet absorption time. However, when the angle does not become 0.5 ° or less even after 600 seconds, since the influence of evaporation cannot be ignored, the droplet absorption time is set to 600 seconds or more.
The coefficient of static friction was measured, and the measurement method was as follows. That is, a polished silicon wafer having a diameter of 2 inches (50 mm) is bonded to a lead weight having a diameter of 2 inches, and the thickness of the weight is set so that the load pressure is about 200 g / cm ² which is similar to that during normal polishing. Adjust. A backing pad for evaluation is attached to a ceramic flat plate with double-sided tape, immersed in pure water for a predetermined time in advance, and a silicon wafer with a weight is placed on the surface of the backing pad. Pull the wire horizontally and measure the maximum tensile force. The coefficient of static friction is calculated from the ratio of the maximum tensile force and the weight of the weight.

(Experiment 1)
Using a commercially available wet coagulation method manufactured by Nitta Haas backing pad “R301”, the droplet absorption time was measured by the above measurement method and found to be 5 seconds. Using this water-absorbing holding film, the static friction coefficient was measured under a pressure comparable to the polishing load (200 g / cm ² ). When a hydrophilic wafer after SC-1 cleaning was used, 0.49 was obtained. In the case of water repellency, it was 0.55, and the coefficient of friction was larger when a water repellant wafer was used. When the polishing was actually performed using the backing pad, when a water-repellent wafer washed with hydrofluoric acid was used, the edge portion was not soiled, but a hydrophilic wafer was used. In some cases, edge contamination was detected on 20% of the wafers.

From the above, it was found that increasing the coefficient of friction between the workpiece and the backing pad would be effective if the workpiece was made water-repellent.
However, when the work is made water-repellent, there is a problem that the work itself tends to adsorb particles and the like as compared with the case where the work is hydrophilic.

  Therefore, a method for keeping the friction coefficient between the workpiece and the backing pad high while keeping the workpiece in a hydrophilic state was studied. Then, instead of making the workpiece water-repellent, the following experiment was conducted by assuming that the water-repellent backing pad can prevent the formation of a water film between the workpiece and the backing pad.

(Experiment 2)
Using a backing pad having a water-repellent holding film having a droplet absorption time of 600 seconds or more, the static friction coefficient was measured using a silicon wafer that was subjected to hydrophilic treatment by washing with SC-1. As a result, the coefficient of static friction was 0.59, which was a relatively high value. When this backing pad was actually used to polish using a hydrophilic wafer, no dirt such as particles occurred on the edge portion.
From the above, it was found that even when a hydrophilic workpiece is polished, the friction coefficient between the workpiece and the backing pad can be kept high by using a water-repellent backing pad.

  Thus, the coefficient of friction increases by making the holding film of the backing pad water repellent. However, in the polishing apparatus, the workpiece needs to be adsorbed to the backing pad during conveyance. For this purpose, since the surface tension of water is used, it is necessary to wet the holding film with water in advance. However, if the backing pad has a strong water-repellent holding film, the work cannot be sufficiently adsorbed due to poor water retention, and there is a risk of the work falling during transport.

  Therefore, the present inventor further provides a method for maintaining a high coefficient of friction between the workpiece and the backing pad even during polishing of the workpiece without making the workpiece water-repellent and without excessively water-repellent the holding film. We conducted intensive research. And in order to improve the water retention, a two-layered backing pad was adopted that adopted a water-absorbing film in the lower layer and a water-repellent film on the surface side of the backing pad in contact with the workpiece. It is found that if the workpiece is polished by using the polishing pad, the friction coefficient between the workpiece and the backing pad can be kept high even during the polishing, and the backing pad can have water retention to such an extent that the conveyance is not hindered. Was completed.

  Hereinafter, the present invention will be described more specifically with reference to the accompanying drawings, but the present invention is not limited thereto.

  FIG. 1 schematically shows an example of a backing pad according to the present invention. The backing pad 101 in FIG. 1A is laminated on the base material 11, the water absorbent resin layer 12 laminated on the base material 11, and the water absorbent resin layer 12, and is more water absorbent than the water absorbent resin layer 12. And a low water-repellent resin layer 13. The water absorbent resin layer 12 and the water repellent resin layer 13 constitute a holding film 16.

The water-absorbing resin layer 12 and the water-repellent resin layer 13 are not particularly limited as long as they have a certain degree of water retention, but preferably have a foam structure so that more water can be easily retained. Further, in order to form a foamed structure inexpensively, easily, and reliably, it is preferable to prepare a urethane resin by a wet coagulation method. The pores 15 of the water repellent resin layer 13 are preferably partially open upward.
Further, as another example of the backing pad according to the present invention shown in FIG. 1B, a structure in which the water-repellent resin layer 13 is laminated on the bubbles 14 of the water-absorbent resin layer 12 opened upward is also possible. Good.

The droplet absorption time of the water absorbent resin layer 12 can be 10 seconds or less, and the droplet absorption time of the water repellent resin layer 13 can be more than 10 seconds, but is not particularly limited.
Further, it is preferable that the thickness of the water-repellent layer 13 is at least thinner than that of the water-absorbent resin layer 12 so that water can freely move between the resin layers of the water-absorbent resin layer 12 and the water-repellent resin layer 13.

The method for producing such a backing pad according to the present invention is not particularly limited, but for example, it can be suitably produced by the following procedure.
First, a water repellent resin film is produced as follows. For example, a polyethylene terephthalate (PET) film serving as a base material is prepared, and this PET film is dissolved in a water-soluble organic solvent such as dimethylformamide (DMF), dimethyl sulfoxide (DMSO), tetrahydrofuran (THF), or an ether type. Alternatively, a urethane resin such as carbonate is applied, wet coagulated, washed and dried. After the drying is finished, the PET film is peeled off, and the porous silver surface layer on the surface is removed to a predetermined thickness to obtain a water repellent resin film. At this time, a fluorine-based or silicone-based resin may be added to the water-soluble organic solvent to be applied.

  Next, a water-absorbing resin layer is produced as follows. An ester-based, ether-based, or carbonate-based urethane resin and a water-absorbent resin are added to a water-soluble organic solvent such as DMF, DMSO, or THF in a weight ratio of 1% to 30% and dissolved. Examples of the water absorbent resin include, but are not limited to, polyester, polyacrylamide, polyvinyl alcohol, polymethyl methacrylate, polyvinyl chloride, polysulfone, nylon 6, polyurethane, polycarbonate, and the like. Further, a surfactant may be further added to the water-soluble organic solvent to which the urethane resin and the water absorbent resin are added. The mixture thus obtained is applied to a substrate such as a PET film different from that used for producing the water-repellent resin film, wet coagulated, washed, and then dried. In this way, a film in which the water-absorbing resin layer is laminated on the substrate is obtained. In addition, when the water-absorbing resin layer is prepared in this way, a porous silver surface layer is formed near the surface, but this porous silver surface layer is removed by grinding or the like so that relatively large bubbles open on the surface. It may be.

  The backing pad according to the present invention can be produced by applying an adhesive to the above water-repellent resin film and press-bonding the adhesive to the water-absorbent resin layer.

Further, the backing pad according to the present invention can be manufactured by the following procedure.
First, a film in which a water-absorbing resin layer is laminated on a substrate is produced by the same method as described above. Next, a water-repellent resin layer is formed by applying the above-described water-repellent resin material on the water-absorbent resin layer and curing it. This film is washed and dried to form a backing pad in which a water-absorbing resin layer is laminated on a substrate, and a water-repellent resin layer is laminated on the water-absorbing resin layer.

When a workpiece is polished using the backing pad according to the present invention, for example, the backing pad is attached to a polishing apparatus 38 as shown in FIG.
FIG. 2 shows an enlarged schematic of an example of a workpiece polishing apparatus having such a backing pad. In the workpiece polishing apparatus according to the present invention, the backing pad 101 is attached to the holding plate body 18 by the double-sided tape 17 or the like. A template 20 is attached to the water-repellent resin layer 13 side of the backing pad 101 with a double-sided tape 19 or the like.
The workpiece W is held inside the template 20 by the workpiece holding means configured as described above and attached to the holding board main body 18.
The workpiece W thus held by the workpiece holding means is polished by being brought into sliding contact with the polishing cloth 23 on the surface plate 22.

  By using the backing pad and the workpiece polishing apparatus as described above, when no polishing load is applied, the surface of the upper film is replenished with appropriate moisture due to the presence of the water-absorbing resin layer 12, and transported in the polishing machine. Since the work W can be adsorbed to the holding film 16 and the portion of the holding film 16 that is in contact with the work W is water-repellent, water contained in the holding film is blotted by the polishing load during polishing. Even if it comes out, since a water film is not excessively formed between the back surface of the workpiece W and the surface of the holding film 16 and is absorbed by the water-absorbent resin layer, the friction coefficient between the workpiece W and the holding film 16 is lowered. Without rotation, the rotation of the workpiece W can be suppressed.

EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples and comparative examples of the present invention, but the present invention is not limited to these.
Example 1
First, a backing pad was produced as follows.
A water-repellent urethane resin was applied to a PET film as a base material, wet coagulated, washed and dried. Next, the PET film was peeled off and ground to remove the surface silver layer to a predetermined thickness, thereby obtaining a water-repellent foamed urethane film. Next, a water-absorbing urethane resin was applied to the PET film, wet coagulated, washed and dried, and a water-absorbing foamed urethane film laminated on the PET film was obtained. Next, an adhesive was applied to the water-repellent foamed urethane film, and pressure-bonded to the water-absorbing urethane film. A double-sided tape was pressure bonded to the PET film surface of the backing pad thus obtained, and cut out to a predetermined size.

Using the backing pad thus manufactured, a silicon wafer is used as a workpiece before polishing, and the pressure is approximately the same as the polishing load (200 g / cm ²⁾ in the case of hydrophilic treatment and water repellency treatment. ) To measure the coefficient of static friction. As a result, it is 0.59 for hydrophilic wafers and 0.59 for water-repellent wafers. If this holding film is used for both hydrophilic and water-repellent wafers, it will be better than a commercially available holding film. It has been confirmed that even when a hydrophilic wafer is used, a friction coefficient equal to that of a combination of a commercially available holding film and a water-repellent wafer can be obtained. Next, the workpiece was actually polished using the backing pad.

  After polishing, contamination of the wafer edge was detected using an automatic wafer edge defect inspection apparatus “RXW-1225S” manufactured by Raytex Co., Ltd. The defect detection principle of this apparatus is as follows. That is, the presence or absence of defects or dirt is detected by irradiating the entire periphery of the wafer with laser light and receiving the scattered light. When a defect or the like has occurred, an angle from the notch of the defect or the like is obtained, the defect or the like is photographed with a CCD camera, and pass / fail is determined by image processing.

  As a result, even when a water-repellent wafer or a hydrophilic wafer was used, the edge portion was not soiled (FIG. 5). Thereby, the effect of the backing pad of the present invention was confirmed.

(Example 2)
The surface porous silver surface layer of the water-absorbent resin layer laminated on the PET film produced in the same manner as in Example 1 was removed by grinding, dried after washing with water. Next, a water-repellent resin raw material in which a fluororesin was dissolved in a quick-drying organic solvent was applied to the surface of the film, dried and cured. Next, this film was washed with water and dried to obtain a backing pad. A double-sided tape was pressure-bonded to the PET film surface of the backing pad thus obtained and cut out to a predetermined size.

When the droplet absorption time of the backing pad produced in this way was measured, it was 600 seconds or more. Further, using a silicon wafer, the static friction coefficient was measured under the same pressure as the polishing load (200 g / cm ² ) between the hydrophilic treatment and the water repellent treatment. As a result, in the case of a hydrophilic wafer, it becomes 0.54, and in the case of a water-repellent wafer, it becomes 0.54. If this holding film is used for both a hydrophilic wafer and a water-repellent wafer, a commercially available holding film is obtained. It was confirmed that even when a hydrophilic wafer is used, a friction coefficient equivalent to that of a combination of a commercially available holding film and a water-repellent wafer can be obtained.

Next, the workpiece was actually polished using the backing pad.
After polishing, the wafer edge contamination was detected in the same manner as in Example 1.

  As a result, no contamination occurred on the edge portion even when a water-repellent wafer was used or a hydrophilic wafer was used. Thereby, the effect of the backing pad of the present invention was confirmed.

(Comparative example)
The static friction coefficient was measured in the same manner as in the Examples using a conventional backing pad having a hydrophilic holding film. Further, the silicon wafer was polished using the backing pad, and the contamination of the wafer edge was detected after the polishing.

As a result, the coefficient of static friction was 0.25 in the case of a hydrophilic wafer and 0.35 in the case of a water-repellent wafer, and greatly decreased in the case of a hydrophilic wafer.
Further, when a hydrophilic wafer was used, the edge portion was soiled (FIG. 6).

  The present invention is not limited to the above embodiment. The above-described embodiment is an exemplification, and the present invention has any configuration that has substantially the same configuration as the technical idea described in the claims of the present invention and that exhibits the same effects. Are included in the technical scope.

It is a schematic sectional drawing which shows the backing pad which concerns on this invention, (a) is the example, (b) is another example. It is a schematic sectional enlarged view which shows an example of the grinding | polishing apparatus which comprised the backing pad concerning this invention. 1 is a partial schematic view showing an example of a workpiece polishing apparatus. It is a schematic sectional drawing of the conventional backing pad, (a) is a schematic sectional drawing which shows the step in which the porous silver surface layer was formed in the surface, (b) is a porous silver surface layer removed, and a pore is It is a schematic sectional drawing which shows the step opened by the surface. It is explanatory drawing which shows the CCD image which copied the edge part of the workpiece | work of an Example, and the corresponding position in the workpiece | work of the image. It is a CCD image which copied the edge part of the workpiece | work of a comparative example.

Explanation of symbols

11 ... Base material, 12 ... Water-absorbing resin layer, 13 ... Water-repellent resin layer,
14 ... pores, 15 ... pores, 16 ... holding film, 17 ... double-sided tape,
18 ... Main body of holding plate, 19 ... Double-sided tape, 20 ... Template, 22 ... Surface plate,
23 ... polishing cloth, 101 ... backing pad,
31 ... Wafer holding means, 32 ... Holding plate body, 33 ... Polishing slurry,
34 ... backing pad, 35 ... template, 36 ... polishing cloth,
37 ... surface plate,
41 ... Substrate, 42 ... Holding film, 43 ... Pore, 44 ... Porous silver surface layer,
45 ... holding film, 46 ... open pores,
W ... Work.

Claims (5)

A backing pad for holding the workpiece when polishing the workpiece, comprising at least a base material, a water absorbent resin layer laminated on the base material, and a water absorbent resin layer laminated on the water absorbent resin layer. It is composed of a water repellent resin layer having a lower water absorption than the resin layer, and holds the surface of the workpiece opposite to the surface to be polished in close contact with the surface of the water repellent resin layer by the surface tension of water. The water-repellent resin layer is obtained by applying a water-repellent resin raw material to the water-absorbent resin layer and curing, and the water-absorbent resin layer and the water-repellent resin layer have a foam structure, The pores of the water-repellent resin layer are partially open upward, and the pores of the water-absorbent resin layer are not open upward, but a droplet of 4 μL of pure water is dropped and the contact angle When the time taken to reach 0.5 ° or less is the droplet absorption time A backing pad, wherein the water-absorbing resin layer has a droplet absorption time of 10 seconds or less, and the water-repellent resin layer has a droplet absorption time of more than 10 seconds. The backing pad according to claim 1, wherein at least one of the water absorbent resin layer and the water repellent resin layer is made of a polyurethane resin. In a workpiece polishing apparatus that holds a workpiece via a workpiece holding means attached to a holding board body and polishes the workpiece surface by sliding the workpiece against a polishing cloth, the workpiece holding means includes at least the workpiece. its ground surface is intended to include a backing pad for holding the opposite face polishing apparatus of the workpiece, characterized in that the backing pad is backing pad according to claim 1 or claim 2. 4. The workpiece polishing apparatus according to claim 3 , further comprising a template for positioning the workpiece on a side of the backing pad that is in close contact with the workpiece. A method for polishing a workpiece, wherein at least the workpiece polishing apparatus according to claim 3 or 4 is used, one side of the workpiece is held in close contact with the backing pad, and an abrasive is supplied to the polishing cloth. However, the workpiece | work grinding | polishing method characterized by including the process of grind | polishing by making the to-be-polished surface of the said workpiece | work slide-contact with the said polishing cloth.

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