JP2851808B2 - Polishing wafer holding member and method of mounting the wafer holding member on a surface plate - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a holding member used for holding a polishing wafer member when holding a polishing wafer holding member such as a semiconductor wafer on a surface plate such as a polishing machine and polishing. The present invention also relates to a method for mounting the polishing wafer holding member on a surface plate of a polishing machine.

[0002]

2. Description of the Related Art In recent years, in the semiconductor industry, the degree of integration of ICs has dramatically increased, and 4M, 16M, and even 64M
Is in progress.

[0003] Under such circumstances, the demand for improving the quality of the surface of the wafer, which is the base of the IC, is becoming increasingly sophisticated. Of course, the chemical and electrical properties of the wafer are natural, but in order to increase the degree of integration of ICs, the minimum line width that constitutes the devices provided on the wafer has become increasingly smaller, from 0.5 microns The demand for 0.35 microns is increasing.

[0004] In order to enable such high-definition processing, the demand for the flatness of the wafer surface, that is, the thickness accuracy, has been increasingly strong. That is, the wafer after the final mirror finish polishing has a thickness variation (T
total thickness variation)
(TTV) of 1 micron or less, thickness variation over 20 mm square to be one IC chip (Local th
It is becoming increasingly required that the thickness of the ink variance (LTV) be 0.2 microns or less.

In order to achieve the required accuracy, in the wafer polishing step, it is necessary to mount the wafer on a surface plate of a polishing machine exactly parallel to the surface of the surface plate. Generally, the following two methods have conventionally been used for mounting a wafer on a polishing machine surface plate.

[0006] One is a method in which a molten wax is applied to the surface by heating the surface plate, and the wafer is fixed to the surface of the surface plate through this.

According to this method, the wafer is fixed to the surface of the platen to perform a polishing operation. After the polishing operation is completed, the platen is heated again to melt the wax, and the wafer is removed from the surface of the surface plate. Is washed with an organic solvent to remove the attached wax.

This method is satisfactory because the thickness difference of the polished wafer is small, but the heating and cooling of the surface plate are performed once before and after each polishing in the process. There are many drawbacks, such as a large number of occurrences, the presence of a thermal step of heating and melting the wax, the use of a harmful organic solvent for washing and removing the wax, and the difficulty in automation of the step. Another method is a method in which a polishing wafer holding member is adhered to a surface plate in advance, and a wafer is adsorbed on a surface of the polishing plate via a liquid such as water.

According to this method, it is easy to mount and remove the wafer on and from the surface plate in the polishing operation, so that it is efficient and suitable for automation. There was a problem that it was slightly inferior to the law.

In order to solve this problem, the precision of the polishing wafer holding member has been increased. However, in order to mount the highly precise member on a surface plate of a polishing machine, a conventional pressure-sensitive member has been used. It is common to use an adhesive, and this process has traditionally relied entirely on manual techniques, and there are many troubles such as wrinkles and air bubbles, and an adhesive layer provided on the back side of the wafer holding member. Because of the thickness, there are many thickness differences,
In addition, during the polishing operation, a plastic deformation of the pressure-sensitive adhesive layer, which is called a cold flow, occurs, so that the accuracy of the finished thickness of the polished wafer becomes unstable.

[0011]

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and an object of the present invention is to provide a polishing wafer holding member with high accuracy without problems such as air bubbles.
In addition, it is an object of the present invention to provide a polishing wafer holding member which can be easily adhered to a polishing machine surface plate and minimize a thickness change during a polishing operation, and a method of mounting the wafer holding member to the surface plate. .

[0012]

A polishing wafer holding member according to the present invention comprises a transparent sheet-like base material, a surface layer formed on the surface of the base material and capable of mounting a polishing wafer, and An electron beam-curable pressure-sensitive adhesive layer formed on the back side of the base material, whereby the object is achieved. It is preferable that fine irregularities for venting air are formed on the back surface of the pressure-sensitive adhesive layer. Further, it is preferable to have a release sheet releasably attached to the back surface side of the pressure-sensitive adhesive layer. Preferably, the surface layer has a foam layer.

The method of mounting the polishing wafer holding member on the surface plate according to the present invention comprises the steps of: mounting the electron beam curing type adhesive layer of the polishing wafer holding member on a polishing machine surface plate; Irradiating an electron beam from the surface layer side of the member to cure the pressure-sensitive adhesive layer and bond the polishing wafer holding member to a surface plate, thereby achieving the above object. It is preferable that the method further includes a step of placing a transparent flat plate on the polishing wafer holding member.

Hereinafter, the present invention will be described in detail.

As the transparent sheet-like substrate used in the present invention, various synthetic resin sheets such as polyethylene terephthalate, polyetherimide, polyurethane and the like can be used. For example, polyester films (trade name, Lumirror, Manufactured by Toray Industries, Inc.).

The surface layer laminated on the surface of the sheet-like substrate is preferably formed from a light-transmitting foam layer.
For example, urethane polymer, vinyl chloride polymer, vinyl chloride-vinyl acetate copolymer, vinyl chloride-vinyl acetate-
A foamed layer composition having a vinyl polymer such as a vinyl alcohol terpolymer and dimethylformamide can be provided on the above-mentioned base material to form a foamed layer by a wet coagulation method. The surface of the foam layer, especially the skin layer formed on the surface, is preferably buffed so that the wafer can be easily absorbed.

Specifically, it is preferable to laminate a sheet having a foamed layer made of a polymer selected from polyurethane or vinyl by a wet coagulation method on a substrate.

The polymer constituting the above-mentioned surface layer is usually selected from light-transmitting materials without blending a filler such as carbon black.

The pressure-sensitive adhesive layer is provided on the back surface of the base material (on the surface plate on the polishing machine), and the form is such that air can be easily released when the wafer holding member is placed on the surface of the platen. There is no particular limitation as long as it can be performed. For example, it can be formed of fine unevenness formed by parallel strips arranged in one direction, or even more, and the surface side can also be formed by a layer having such protrusions and unevenness.

The pressure-sensitive adhesive forming the pressure-sensitive adhesive layer is selected from electron beam (especially, light) curable resins, and usually comprises a reactive oligomer, a photopolymerizable monomer, a photopolymerization initiator, an additive and the like.

Examples of the reactive oligomer include oligomers mainly containing one or several double bonds in the molecular chain, and include polyester compounds, polyurethane compounds, polyether compounds, epoxy compounds, polybutadiene compounds and the like.

As the photopolymerizable monomer, a monofunctional or polyfunctional monomer is used. For example, ethylene glycol diacrylate, diethylene glycol diacrylate, triethylene glycol diacrylate, propylene glycol diacrylate, trimethylolpropane triacrylate, pentaerythritol tetraacrylate, and methacrylates corresponding to the above di- or polyacrylates, methyl acrylate, Ethyl acrylate, butyl acrylate,
2-ethylhexyl acrylate, methyl methacrylate, ethyl methacrylate, butyl methacrylate, cyclohexyl acrylate, cyclohexyl methacrylate, glycidyl acrylate, glycidyl methacrylate, 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate,
Styrene, vinyl toluene, acrylamide, methyl vinyl ether and the like can be used.

Examples of the photopolymerization initiator include carbonyl compounds such as benzoin, benzoin methyl ether, diacetyl, benzophenone, benzaldehyde, acetophenone, and benzyl; sulfur compounds such as diphenyl disulfide and dibenzothiazolyl disulfide; Halogen compounds such as butadiene, octachlorobutene, and hexachlorobenzene, and azobisisobutyronitrile can be used as initiators that generate radicals upon irradiation with light.

As the above additives, hydroquinone, benzoquinone and the like can be used as stabilizers, and butyl catechol and the like can be used for improving adhesiveness.

A release sheet (or release film) is usually attached to the back side of the pressure-sensitive adhesive layer, and the pressure-sensitive adhesive layer is kept until the polishing wafer holding member of the present invention is used. It is protected by the release sheet. The irregularities formed on the back side of the pressure-sensitive adhesive layer may be formed by transferring the irregularities provided on the release sheet.

The set of the wafer holding members for polishing stacked in this way is preferably packaged with a light-shielding sheet. The basic configuration of the polishing wafer holding member of the present invention,
For example, it is disclosed in JP-A-5-47392.

Next, an example of a method for manufacturing a polishing wafer holding member of the present invention will be described with reference to the drawings.

As shown in FIG. 1, a foam layer composition containing a polymer selected from polyurethane or vinyl is applied to the upper surface of a sheet-like substrate 1 and the foam layer 2 is formed as a surface layer by a wet coagulation method. To form Thereafter, the surface of the foam layer 2 is buffed. The location where the foam layer 2 is buffed can be appropriately selected. As shown by the line A in FIG. 1, the skin layer 3 formed on the surface of
2 is obtained by buffing, and an upright-type wafer holding member shown in FIG. 3 is obtained by buffing by C-line.

Next, as shown in FIG. 3, an adhesive layer 4 is provided on the back side of the substrate 1 (on the surface plate on the polishing machine), and a release sheet 5 is provided on the back side of the adhesive layer 4. Is attached to form the polishing wafer holding member 10. A large number of parallel ridges 4a are formed on the pressure-sensitive adhesive layer 4.

In mounting the polishing wafer holding member 10 of the present invention thus constructed on a surface plate of a polishing machine, first, the surface plate of the polishing machine is removed and cleaned, and the surface of the surface of the surface plate is mounted. Install horizontally with the top facing up. Next, the polishing wafer holding member is taken out of the package, the release sheet on the adhesive surface is removed, and as shown in FIG.
Set the surface of the plate on the surface of the platen. At this time, it is desirable that the polishing wafer holding member 10 be slightly curved and be allowed to stand still so that the center portion thereof comes into contact with the surface of the platen first. At this time, it is preferable that the surface plate 6 is heated to an appropriate temperature at which the pressure-sensitive adhesive layer 4 is softened.

In this case, the temperature of the platen 6 does not need to be higher than the wax melting temperature as in the wax method, and may be 40 ° C. or less, which is the temperature at which the pressure-sensitive adhesive layer 4 is softened. In addition, since it is not necessary to heat the platen 6 until the polishing wafer holding member 10 is deteriorated and replaced, the heat history of the platen 6 is also very low. It is very useful from the viewpoint of maintaining the plane accuracy.

Next, the polishing wafer holding member 1 that has been left still
0 is uniformly pressed from the upper surface. The pressing method may be an appropriate method, but the pressing force is preferably in a range not exceeding 1 kg / cm ² , and the pressing method is, for example, pressing with a flat plate through an elastic material having a sufficient thickness, or the most desirable method. For example, a method of covering the stationary polishing wafer holding member 10 with a plastic sheet from above, and suctioning the air therebelow to apply a negative pressure to apply pressure may be used.

In this way, air is not interposed at the interface with the platen 6 due to the unevenness provided on the photocurable pressure-sensitive adhesive layer 4 on the back surface of the base material of the polishing wafer holding member 10. The ridges 4a are brought into contact with the surface of the surface plate heated to an appropriate temperature, softened and adapted to and adhere to the surface of the surface plate.

Next, immediately after removing the means for pressurizing, a light-transmitting flat plate having a sufficient flatness, particularly synthetic quartz having a high transmittance in the ultraviolet region, is formed on the upper surface of the polishing wafer holding member 10. The optical glass flat 7 or the like made is placed thereon, and the adaptation of the ridges 4a of the adhesive layer 4 to the surface of the platen is further advanced. In this case, if necessary, a pressing means may be further added from above the optical flat 7. In this manner, the pressure bonding of the polishing wafer holding member 10 to the surface plate 6 may be performed in two stages, or may be performed only in the latter stage. By doing so, it is preferable to apply pressure to the extent that the concave and convex concave portions provided on the pressure-sensitive adhesive layer 4 reduce the area by 30% or more. As a result, it is possible to correct the unevenness of the flatness of the surface constituted by the ridges 4 a existing in the pressure-sensitive adhesive layer 4, and to install the polishing wafer holding member 10 in parallel with the surface of the platen with high precision.

Further, after the pressing means on the optical glass flat 7 is removed, an electron beam is irradiated from above the glass flat 7 from the electron beam irradiating means 8 to light-cur the adhesive layer 4.

As the electron beam irradiation means, ultraviolet irradiation means such as a high-pressure mercury lamp, a low-pressure mercury lamp, and a chemical lamp can be used. The lamp output requires 10 to 200 microwatts per square cm of the pressure-sensitive adhesive layer to be cured. By light curing the pressure-sensitive adhesive layer 4 in this manner, the adhesive strength is increased, and thus the thickness of the pressure-sensitive adhesive layer 4 may be 20 μm or less. In addition, the plastic deformation of the pressure-sensitive adhesive layer 4 is reduced by light curing.

As described above, in comparison with the conventional case where the polishing wafer holding member is adhered to the surface plate with a pressure-sensitive adhesive, the polishing wafer is formed by the plastic deformation of the thick adhesive during the polishing operation. The adverse effect on the thickness accuracy can be reduced.

After the polishing wafer holding member is stuck on the surface of the platen in parallel with high precision, if necessary, a template provided with a recess hole for positioning or holding the wafer at the position may be used as a polishing wafer. It can be mounted on the upper surface of the foam layer 2 of the holding member by an ordinary method and can be used for polishing.

[0039]

The polishing wafer holding member of the present invention has a transparent sheet-like base material, a surface layer formed on the surface of the base material, on which a polishing wafer can be mounted, and a back surface side of the base material. Having the formed electron beam-curable pressure-sensitive adhesive layer, after adhering the pressure-sensitive adhesive layer of the holding member on the surface of the platen, irradiating the pressure-sensitive adhesive layer with an electron beam from the surface layer side. The holding member can be adhered to the surface of the surface plate.

Therefore, even if the thickness of the pressure-sensitive adhesive layer is relatively thin, the wafer holding member can be firmly adhered to the surface plate, so that the thickness accuracy of the wafer holding member can be improved, and the polishing operation can be performed. The cured adhesive layer does not undergo plastic deformation.

[0041]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be specifically described below based on embodiments.

Example 1 1-1) Preparation of Backing Film As shown in FIG. 1, on a 188-micron polyester film 1 (Lumirror, manufactured by Toray Industries, Inc.), compound I shown in Table 1 was mixed with a 700-micron film. The foamed layer 2 was formed by coating to a thickness and wet-coagulating to form a foamed layer 2. After washing and drying steps, a backing film 11 shown in FIG. 1 was produced. Grind 100 microns of the surface layer of this backing film 11 (C in FIG. 1).
Grinding with a wire) to obtain a backing film 12 shown in FIG.

1-2) Preparation of pressure-sensitive adhesive film with release film Formulation II shown in Table 2 was coated on a 50-micron polyester film (Lumirror, manufactured by Toray Industries Co., Ltd.) to a thickness of 20 μm and prepared in advance. UV irradiation through a mask with micron slits, Formulation I
I was light cured. Thereafter, the uncured portion of Formulation II was removed using a mixture of pure water and alcohol, and 1
A release film having irregularities of 0 micron was produced. The photocurable pressure-sensitive adhesive composition II shown in Table 3 was added to this release film.
I was coated to a thickness of 20 microns to obtain an adhesive film with a release film.

1-3) Preparation of Wafer Holding Member for Polishing As shown in FIG. 3, the above-mentioned adhesive film was bonded to the polyester film 1 side of the above-mentioned backing film 12, and a backing film with a photocurable adhesive film ( Polishing wafer holding member) 10 was obtained.

1-4) Hardening of Pressure-Sensitive Adhesive Layer by Irradiation of Ultraviolet Light The release film 5 of the polishing wafer holding member 10 is peeled off, and the surface of the pressure-sensitive adhesive is polished with a ceramic upper platen (485).
mm diameter) 6. Thereafter, an optical flat 7 made of quartz weighing 5 kg was placed evenly, and allowed to stand for 30 minutes, so that the adhesive layer 4 was adapted to the upper surface plate 6. Ultraviolet rays were irradiated through a quartz optical flat 7 for 20 minutes from a distance of 30 cm using a high-pressure mercury lamp (1 kW) to cure the adhesive layer 4 (FIG. 4).

1-5) Adhesion of Template A template (outside diameter: 485 mm, with seven 6-inch pockets) made of a glass epoxy sheet is hot-coated on the surface side of the polishing wafer holding member 10 bonded to the ceramic platen 6. Bonding was performed using a melt adhesive.

At this time, the bonding conditions are 80 ° C., 2 minutes, and 0.
Bonding was performed under a load of 5 kg / cm ² . Thus, a wafer holder was completed.

1-6) Polishing Test The above wafer holder was evaluated using an SPM-19 single-side polishing machine manufactured by Fujikoshi Machinery.

The processed wafer is a silicon single crystal P (100)
The polishing conditions are described in Table 4 using a 6-inch diameter wafer.

The accuracy of the shape of the polished wafer was evaluated using an optical interference type wafer flatness tester; FT-90A wafer flatness tester manufactured by Nidek.

The processing accuracy of a wafer polished using the wafer holder is TTV: 0.8 μm, LTV: 0.15
Micron.

(Example 2) 2-1) Production of backing film 188 micron polyester film 1 (Lumirror,
Toray) was coated with Formulation I shown in Table 1 to a thickness of 700 microns and wet-solidified to form a foam layer 2,
After the washing and drying steps, the backing film 11 shown in FIG. 1 was produced. Surface layer 1 of this backing film 11
The backing film shown in FIG. 2 was obtained by grinding 00 micron.

The film was peeled from the polyester,
The backing film is again adhered to another polyester film using an adhesive, and the surface layer 100
Micron is ground and the backing film 13 shown in FIG.
Was prepared.

2-2) Preparation of pressure-sensitive adhesive film with release film In the same manner as in step 1-2) shown in Example 1, a photocurable pressure-sensitive adhesive compound III shown in Table 3 was added to the release film. Was coated to a thickness of 20 microns to prepare an adhesive film with a release film.

2-3) Preparation of Polishing Wafer Holding Member The above-mentioned adhesive film was attached to the polyester film 1 side of the above-mentioned backing film to produce a backing film with a photocurable adhesive film, and the backing shown in FIG. A film (polishing wafer holding member) was completed.

2-4) Curing of Pressure-Sensitive Adhesive Layer by Irradiation of Ultraviolet Light The release sheet 5 of the polishing wafer holding member 10 was peeled off, and the pressure-sensitive adhesive surface was fixed to a ceramic upper surface plate of a polisher as in Example 1. (485 mm diameter) 6. Thereafter, an optical flat 7 made of quartz weighing 5 kg was placed evenly, and allowed to stand for 30 minutes, so that the adhesive layer 4 was adapted to the upper surface plate 6. Ultraviolet rays were irradiated through the quartz optical flat 7 for 20 minutes from a distance of 30 cm using a high-pressure mercury lamp (1 kW) to cure the adhesive layer 4.

2-5) Adhesion of Template A template (outside diameter: 485 mm, with six 6-inch pockets) made of a glass epoxy sheet is hot melted on the surface side of the polishing wafer holding member 10 bonded to the ceramic platen 6. Bonded using an adhesive. The bonding was performed at 80 ° C. for 2 minutes with a load of 0.5 kg / cm ² . Thus, a wafer holder was completed.

2-6) Polishing Test The wafer holder was evaluated using a single-side polishing machine SPM-19 manufactured by Fujikoshi Machinery. The processed wafer was a silicon single crystal P (100) wafer having a diameter of 6 inches, and the polishing conditions were described in Table 4. The shape accuracy of the polished wafer was evaluated using an optical interference type wafer flatness tester; FT-90A wafer flatness tester manufactured by Nidek.

The processing accuracy of the wafer polished using this wafer holder is TTV: 0.8 μm, LTV: 0.2
Micron.

(Example 3) 3-1) Production of backing film As shown in FIG. 1, on a 188-micron polyester film 1 (Lumirror, manufactured by Toray Industries Co., Ltd.), compound I shown in Table 1 was mixed with 700-micron film. The foamed layer 2 was formed by coating to a thickness and wet-coagulating to form a foamed layer 2. After washing and drying steps, a backing film 11 shown in FIG. 1 was produced. Grind 100 microns of the surface layer of this backing film 11 (C in FIG. 1).
Grinding with a wire) to obtain a backing film 12 shown in FIG.

3-2) Preparation of pressure-sensitive adhesive film with release film Formulation II shown in Table 2 was coated on a 50-micron polyester film (Lumirror, manufactured by Toray Industries Co., Ltd.) to a thickness of 20 μm. UV irradiation through a mask with micron slits, Formulation I
I was light cured. Thereafter, the uncured portion of Formulation II was removed using a mixture of pure water and alcohol, and 1
A release film having irregularities of 0 micron was produced. The photocurable pressure-sensitive adhesive composition II shown in Table 3 was added to this release film.
I was coated to a thickness of 20 microns to obtain an adhesive film with a release film.

3-3) Preparation of Polishing Wafer Holding Member As shown in FIG. 3, the above-mentioned adhesive film was attached to the polyester film 1 side of the above-mentioned backing film 12, and a backing film with a photocurable adhesive film ( Polishing wafer holding member) 10 was obtained.

3-4) Adhesion of Template A template (outside diameter: 485 mm, with 7 6-inch pockets) made of a glass epoxy sheet was adhered to the ceramic platen 6 using a double-sided adhesive tape. The bonding was performed at 40 ° C. for 1 minute with a load of 0.5 kg / cm ² .

3-5) Curing of Pressure-Sensitive Adhesive Layer by Irradiation of Ultraviolet Light The backing film was cut accurately to 5.99 inches, the release film was peeled off, and the surface of the pressure-sensitive adhesive was polished with a ceramic upper platen (glass). (A 6-inch pocket portion of a template made from an epoxy sheet). Thereafter, a quartz optical flat having an outer diameter of 5.99 inches is inserted into the pocket, and a weight of 5 k is placed on the optical flat.
g, an optical flat made of quartz having an outer diameter of 485 mm was placed evenly, and allowed to stand for 30 minutes to allow the pressure-sensitive adhesive layer to conform to the upper platen. Ultraviolet rays were irradiated through a quartz optical flat for 20 minutes from a distance of 30 cm using a high-pressure mercury lamp (1 kW) to cure the adhesive layer (FIG. 4).

3-6) Polishing Test The above wafer holder was evaluated using an SPM-19 single-side polishing machine manufactured by Fujikoshi Machinery.

The processed wafer is a silicon single crystal P (100)
The polishing conditions are described in Table 4 using a 6-inch diameter wafer.

The accuracy of the shape of the polished wafer was evaluated using an optical interference type wafer flatness tester; FT-90A wafer flatness tester manufactured by Nidek.

The processing accuracy of the wafer polished using the wafer holder is as follows: TTV: 0.7 μm, LTV: 0.15
Micron.

(Comparative Example 1) 4-1) Preparation of Backing Film A 188-micron polyester film (Lumirror, manufactured by Toray Industries, Inc.) was coated with Formulation I shown in Table 1 to a thickness of 700 microns, and wet-solidified. Forming a foam layer,
After the washing and drying steps, the backing film 11 shown in FIG. 1 was produced. Surface layer 1 of this backing film 11
The backing film 12 was produced by grinding 00 micron.

4-2) Preparation of Backing Film with Adhesive Film On the polyester film side of the backing film,
A commercially available double-sided tape (ST442, manufactured by Sumitomo 3M) was attached to obtain a backing film with an adhesive film.

This backing film was punched into a 6-inch diameter wafer having the same diameter as the processed wafer to produce a 6-inch diameter backing film with an adhesive film.

4-3) Adhesion of Template to Surface Plate A template made of a glass epoxy sheet was adhered to a ceramic surface plate using a double-sided tape. Bonding was performed by applying pressure by hand and bonding to a surface plate.

4-4) Adhesion of Backing Film to Surface Plate The release sheet of the backing film was peeled off, and the surface of the pressure-sensitive adhesive was adhered to a ceramic upper surface plate of a polishing machine by hand.
At this time, it was stuck so as to match the pocket portion of the template stuck earlier. It was left for 30 minutes to allow the adhesive to adjust to the upper platen. Thus, the wafer holder of Comparative Example 3 was completed.

4-5) Polishing Test The above wafer holder was evaluated using an SPM-19 single-side polishing machine manufactured by Fujikoshi Machinery. The processed wafer was a silicon single crystal P (100) wafer with a diameter of 6 inches, and the polishing conditions were as shown in Table 4.
It described in. The shape accuracy of the polished wafer was evaluated using an optical interference type wafer flatness tester; FT-90A wafer flatness tester manufactured by Nidek.

The processing accuracy of the wafer polished using this wafer holder was 1.5 μm for TTV and 0.9 μm for LTV. The target machining accuracy could not be achieved.

[0076]

[Table 1]

[0077]

[Table 2]

[0078]

[Table 3]

[0079]

[Table 4]

[0080]

According to the present invention, after the adhesive layer of the wafer holding member is adhered to the surface of the surface plate, the adhesive layer is cured by irradiating an electron beam and the wafer holding member can be bonded to the surface plate. As a result, the wafer holding member can be adhered to the polishing machine surface plate with high accuracy without problems such as air bubbles, and the thickness change during polishing operation is minimized, thereby improving the accuracy of the finished thickness of the polished wafer. In addition, the wafer can be easily mounted and removed in a polishing operation, and therefore, it is efficient and suitable for automation.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing a state in which a foam layer is laminated on a base material used for a polishing wafer holding member of the present invention.

FIG. 2 is a cross-sectional view showing a state in which the surface layer of the foam layer shown in FIG. 2 is buffed.

FIG. 3 is a sectional view of one embodiment of a polishing wafer holding member of the present invention.

FIG. 4 is a schematic view showing an operation of attaching the polishing wafer holding member of the present invention onto a surface plate.

FIG. 5 is a sectional view of another embodiment of the polishing wafer holding member of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Base material 2 ... Foam layer 3 ... Skin layer 4 ... Adhesive layer 5 ... Release sheet 6 ... Platen 7 ... Optical flat made of quartz 8 ... Electron beam irradiation means 10 ... Wafer holding member for polishing

Claims (6)

(57) [Claims] 1. A transparent sheet-like base material, and a surface layer formed on a surface of the base material and capable of mounting a polishing wafer,
A polishing wafer holding member, comprising: an electron beam-curable pressure-sensitive adhesive layer formed on the back surface of the substrate. 2. The polishing wafer holding member according to claim 1, wherein fine irregularities for venting air are formed on a back surface of the pressure-sensitive adhesive layer. 3. The polishing wafer holding member according to claim 1, further comprising a release sheet releasably attached to a back surface side of the pressure-sensitive adhesive layer. 4. The method according to claim 1, wherein the surface layer has a foam layer.
3. The polishing wafer holding member according to item 1. 5. A process for mounting the electron beam-curable pressure-sensitive adhesive layer of the polishing wafer holding member according to claim 1 on a surface plate of a polishing machine, and an electron beam from the surface layer side of the polishing wafer holding member. Irradiating the adhesive layer to cure the pressure-sensitive adhesive layer and bonding the polishing wafer holding member to the surface plate. 6. The polishing wafer holding member according to claim 5, further comprising a step of placing a transparent flat plate on the polishing wafer holding member before the step of irradiating the electron beam. How to attach to the surface plate.