JP5275012B2 - Polishing pad and manufacturing method thereof - Google Patents

Description

  The present invention stabilizes flattening processing of optical materials such as lenses and reflecting mirrors, silicon wafers, glass substrates for hard disks, aluminum substrates, and materials that require high surface flatness such as general metal polishing processing, The present invention also relates to a polishing pad (for rough polishing or finish polishing) that can be performed with high polishing efficiency and a method for manufacturing the same. In particular, the polishing pad of the present invention is formed by polishing a glass substrate, or a silicon wafer and a device having an oxide layer, a metal layer, etc. formed thereon, and further laminating and forming these oxide layers and metal layers. It is suitably used for the step of flattening before.

  As a method for flattening the irregularities on the surface of the glass substrate, chemical mechanical polishing (hereinafter referred to as CMP) is generally employed. CMP is a technique in which a polished surface of a glass substrate is pressed against a polishing surface of a polishing pad, and polishing is performed using a slurry-like abrasive in which abrasive grains are dispersed (hereinafter referred to as slurry). A polishing apparatus generally used in CMP includes, for example, a polishing surface plate 2 that supports a polishing pad 1 and a support base (polishing head) 5 that supports an object to be polished (glass substrate) 4 as shown in FIG. And a backing material for uniformly pressing the wafer, and a slurry supply mechanism. The polishing pad 1 is attached to the polishing surface plate 2 by attaching it with a double-sided tape, for example. The polishing surface plate 2 and the support base 5 are disposed so that the polishing pad 1 and the material to be polished 4 supported by each of the polishing surface plate 2 and the support base 5 are opposed to each other, and are provided with rotating shafts 6 and 7 respectively. Further, a pressurizing mechanism for pressing the workpiece 4 against the polishing pad 1 is provided on the support base 5 side.

  As a polishing pad used for such a polishing operation, for example, the following has been proposed. First, a polyurethane resin foam in which polymer foam microelements are dispersed, or a polyurethane resin obtained by stirring an isocyanate prepolymer in the presence of a surfactant to prepare a cell dispersion and adding a chain extender thereto A foam is manufactured in a block shape. Then, a polishing pad manufactured by slicing the block-like polyurethane resin foam to obtain an abrasive sheet and cutting it into a circle has been proposed (Patent Documents 1 and 2).

  Moreover, the following method is proposed as a method of slicing a block-like polyurethane resin foam and producing an abrasive sheet.

  A method for slicing a polishing pad material, wherein the slicing is performed while supplying a lubricant by using a slicer having a facility for supplying the lubricant to the cutting edge of a knife for slicing. Slicing method (Patent Document 3).

  Providing a foamed polyurethane block having an Asker D hardness of 50 or more at room temperature; adjusting the surface hardness of the foamed polyurethane block to an Asker A hardness of 80 to 95; A method for producing a polishing pad for CMP comprising: a step of obtaining a polishing sheet by slicing to a thickness; a step of forming a polishing sheet to obtain a polishing layer; a step of processing the polishing layer into a polishing pad (Patent Document 4) .

  However, the conventional slicing method has problems such as wrinkles and irregularities on the polishing sheet and large variations in thickness. Further, the canna-type slicing methods of Patent Documents 3 and 4 have a problem that the thickness variation becomes large when a thin sheet having a thickness of 5 mm or less is sliced.

Japanese Patent No. 3455517 Japanese Patent No. 3516874 JP 2007-175821 A JP 2005-169578 A

  The present invention provides a slicing method for producing a polishing sheet that is less prone to wrinkles and irregularities on the polishing sheet and has a small thickness variation, and a method for manufacturing a polishing pad using the polishing sheet obtained by the slicing method. With the goal.

  As a result of intensive studies to solve the above problems, the present inventors have found that the above object can be achieved by the manufacturing method shown below, and have completed the present invention.

That is, the present invention is a polishing pad manufacturing method including a slicing step of slicing a polymer foam sheet to prepare a polishing sheet,
The slicing step uses a slicing apparatus having a pair of upper and lower feed rollers and an endless belt-like rotating slice blade, and carries a polymer foam sheet having a thickness of 1 to 3 mm between the rollers, Thereafter, the step of slicing the polymer foam sheet carried out between the rollers with the rotating slice blade,
The interval of the narrowest portion between the rollers is 70 to 90% of the thickness of the polymer foam sheet before being carried between the rollers,
The distance from the narrowest part between the rollers to the tip of the rotary slice blade is 1 to 2 times the thickness of the polymer foam sheet before being carried between the rollers, and the polymer foam sheet The present invention relates to a method for producing a polishing pad, characterized by slicing while adjusting the temperature within a range of glass transition temperature ± 8 ° C. of a polymer foam as a raw material.

  In the slicing step, when the interval of the narrowest portion between the rollers exceeds 90% of the thickness of the polymer foam sheet before being carried between the rollers, the polymer foam sheet is firmly fixed with the upper and lower rollers. Since the sheet cannot be held, the sheet slips and the sheet cannot be conveyed with high accuracy. As a result, wrinkles and irregularities occur in the polishing sheet, and the thickness variation of the polishing sheet increases. On the other hand, when it is less than 70%, the polymer foam sheet is compressed too much and the rigidity of the sheet becomes too large. As a result, it becomes difficult for the slicing blade to enter the sheet, or the slicing blade bites into the sheet, so that the rotation of the slicing blade stops and the slicing cannot be performed efficiently.

  In the slicing step, when the distance from the narrowest portion between the rollers to the tip of the rotary slicing blade is less than 1 times the thickness of the polymer foam sheet before being carried between the rollers, the polymer When the foam sheet comes into contact with the slicing blade, wrinkles are easily generated or broken. On the other hand, when the foam sheet exceeds twice, the thickness variation of the obtained abrasive sheet increases.

  In the present invention, it is necessary to slice the polymer foam sheet while adjusting the temperature of the polymer foam sheet within the range of the glass transition temperature ± 8 ° C. of the polymer foam as the raw material. When the temperature of the polymer foam sheet at the time of slicing is higher than the glass transition temperature of the polymer foam that is the raw material by more than 8 ° C, the polymer foam sheet becomes too soft, so the sheet is sliced. When contacted with the blade, wrinkles are likely to occur or break. On the other hand, when the glass transition temperature is lower than 8 ° C., the hardness of the polymer foam sheet is too high, so that the slice blade becomes difficult to enter the sheet, the slice blade stops rotating, and the sheet slips. It tends to happen.

  The material for the polymer foam sheet in the present invention is not particularly limited, and known materials can be used. For example, polyurethane resin, polyester resin, polyamide resin, acrylic resin, polycarbonate resin, halogen resin (polyvinyl chloride, polytetrafluoroethylene, polyvinylidene fluoride, etc.), polystyrene, olefin resin (polyethylene, polypropylene, etc.), epoxy resin 1 type, or 2 or more types of mixtures, such as a photosensitive resin, is mentioned.

  Polyurethane resin is excellent in abrasion resistance, and it is possible to easily obtain a polymer having desired physical properties by changing the raw material composition, and because fine bubbles can be easily formed by a mechanical foaming method (including a mechanical floss method). It is preferably used as a material for forming an abrasive sheet. Hereinafter, the case where the polymer foam sheet is a polyurethane resin foam sheet will be described.

  The polyurethane resin usually comprises an isocyanate component, a polyol component (high molecular weight polyol, low molecular weight polyol, etc.), and a chain extender.

  As the isocyanate component, a known compound in the field of polyurethane can be used without particular limitation. As the isocyanate component, 2,4-toluene diisocyanate, 2,6-toluene diisocyanate, 2,2′-diphenylmethane diisocyanate, 2,4′-diphenylmethane diisocyanate, 4,4′-diphenylmethane diisocyanate, 1,5-naphthalene diisocyanate, Aromatic diisocyanates such as p-phenylene diisocyanate, m-phenylene diisocyanate, p-xylylene diisocyanate, m-xylylene diisocyanate; ethylene diisocyanate, 2,2,4-trimethylhexamethylene diisocyanate, 1,6-hexamethylene diisocyanate, etc. Aliphatic diisocyanate; 1,4-cyclohexane diisocyanate, 4,4′-dicyclohexylmethane diisocyanate, isophorone diisocyanate Isocyanate, alicyclic diisocyanates such as norbornane diisocyanate. These may be used alone or in combination of two or more.

  Examples of the high molecular weight polyol include polyether polyols typified by polytetramethylene ether glycol, polyester polyols typified by polybutylene adipate, polycaprolactone polyol, and a reaction product of a polyester glycol such as polycaprolactone and alkylene carbonate. Polyester polycarbonate polyol, polyester polycarbonate polyol obtained by reacting ethylene carbonate with polyhydric alcohol and then reacting the resulting reaction mixture with organic dicarboxylic acid, and polycarbonate polyol obtained by transesterification reaction between polyhydroxyl compound and aryl carbonate Etc. These may be used alone or in combination of two or more.

  In addition to the above-described high molecular weight polyol as a polyol component, ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,4-butanediol, 1,6-hexanediol, neopentyl glycol, 1,4 -Cyclohexanedimethanol, 3-methyl-1,5-pentanediol, diethylene glycol, triethylene glycol, 1,4-bis (2-hydroxyethoxy) benzene, trimethylolpropane, glycerin, 1,2,6-hexanetriol, Low such as pentaerythritol, tetramethylolcyclohexane, methyl glucoside, sorbitol, mannitol, dulcitol, sucrose, 2,2,6,6-tetrakis (hydroxymethyl) cyclohexanol, and triethanolamine It can be used in combination with molecular weight polyols. Moreover, low molecular weight polyamines, such as ethylenediamine, tolylenediamine, diphenylmethanediamine, and diethylenetriamine, can also be used in combination. These low molecular weight polyols and low molecular weight polyamines may be used alone or in combination of two or more.

  When the polyurethane resin is produced by the prepolymer method, a chain extender is used for curing the prepolymer. The chain extender is an organic compound having at least two active hydrogen groups, and examples of the active hydrogen group include a hydroxyl group, a primary or secondary amino group, and a thiol group (SH). Specifically, 4,4′-methylenebis (o-chloroaniline) (MOCA), 2,6-dichloro-p-phenylenediamine, 4,4′-methylenebis (2,3-dichloroaniline), 3,5 -Bis (methylthio) -2,4-toluenediamine, 3,5-bis (methylthio) -2,6-toluenediamine, 3,5-diethyltoluene-2,4-diamine, 3,5-diethyltoluene-2 , 6-diamine, trimethylene glycol-di-p-aminobenzoate, polytetramethylene oxide-di-p-aminobenzoate, 4,4′-diamino-3,3 ′, 5,5′-tetraethyldiphenylmethane, 4, 4'-diamino-3,3'-diisopropyl-5,5'-dimethyldiphenylmethane, 4,4'-diamino-3,3 ', 5,5'-tetra Sopropyldiphenylmethane, 1,2-bis (2-aminophenylthio) ethane, 4,4′-diamino-3,3′-diethyl-5,5′-dimethyldiphenylmethane, N, N′-di-sec-butyl -4,4'-diaminodiphenylmethane, 3,3'-diethyl-4,4'-diaminodiphenylmethane, m-xylylenediamine, N, N'-di-sec-butyl-p-phenylenediamine, m-phenylenediamine And polyamines exemplified by p-xylylenediamine and the like, or the low molecular weight polyols and low molecular weight polyamines mentioned above. These may be used alone or in combination of two or more.

  The ratio of the isocyanate component, the polyol component, and the chain extender can be variously changed depending on the molecular weight of each, the desired physical properties of the polishing pad, and the like. In order to obtain a polishing pad having desired polishing characteristics, the number of isocyanate groups of the isocyanate component relative to the total number of active hydrogen groups (hydroxyl group + amino group) of the polyol component and the chain extender is 0.80 to 1.20. Is more preferable, and 0.99 to 1.15 is more preferable. When the number of isocyanate groups is outside the above range, curing failure occurs and the required specific gravity and hardness cannot be obtained, and the polishing characteristics tend to be deteriorated.

  The polyurethane resin can be produced by applying a known urethanization technique such as a melting method or a solution method, but it is preferably produced by a melting method in consideration of cost, working environment, and the like.

  The polyurethane resin can be produced by either the prepolymer method or the one-shot method.

  Examples of the method for producing a polyurethane resin foam include a method of adding hollow beads, a mechanical foaming method, and a chemical foaming method.

  Polyurethane resin foam can be manufactured by batch feeding each component into a container and stirring, or by continuously supplying each component and non-reactive gas to the stirring device and stirring, It may be a continuous production method in which a dispersion is sent out to produce a molded product.

  The polyurethane resin foam sheet may be prepared by putting the raw materials into a reaction vessel and stirring and then pouring into a casting of a predetermined size, or by dissolving the polyurethane resin and extruding it from a T die. May be.

  The thickness of the polyurethane resin foam sheet needs to be 1 to 3 mm. When the thickness is outside the range of 1 to 3 mm, wrinkles and irregularities are likely to occur on the polishing sheet, and the thickness variation increases.

  The width and length of the polyurethane resin foam sheet are not particularly limited, but are about 30 to 160 cm in length and width in consideration of the size and production efficiency of the polishing pad (polishing layer) as the final product.

  The glass transition temperature of the polyurethane resin foam is about 40 to 100 ° C., preferably 50 to 70 ° C.

  The average cell diameter of the polyurethane resin foam is preferably 30 to 150 μm. When deviating from this range, the polishing rate tends to decrease, or the planarity of the polished material (wafer) after polishing tends to decrease.

  The specific gravity of the polyurethane resin foam is preferably 0.3 to 0.8. When the specific gravity is less than 0.3, the surface strength of the polishing layer decreases, and the planarity of the material to be polished tends to decrease. On the other hand, when the ratio is larger than 0.8, the number of bubbles on the surface of the polishing layer decreases, and planarity is good, but the polishing rate tends to decrease.

  The hardness of the polyurethane resin foam is preferably 10 to 50 degrees with an Asker D hardness meter. When the Asker D hardness is less than 10 degrees, the planarity of the material to be polished is reduced. When the Asker D hardness is more than 50 degrees, the planarity is good but the uniformity of the material to be polished is decreased. There is a tendency.

  Hereinafter, a method for producing a polishing pad (polishing layer) including a slicing step of slicing a polyurethane resin foam sheet to produce a polishing sheet will be described.

  FIG. 2 is a schematic view showing the slicing process of the present invention. In the slicing step, a slicing apparatus having a pair of upper feed roller 8 and lower feed roller 9 and an endless belt-like rotating slice blade 10 is used. Examples of the slicing device include a hydraulic slicing device manufactured by Murota Manufacturing Co., Ltd. The slicing apparatus may include an upper surface plate (guide plate) 11, a triangular plate 12, a slicing blade fixing plate 13, and the like. As the rotary slice blade 10, for example, a blade having a circumference of 8 m, a blade width of 10 cm, a tip blade width of 8 mm, and a blade thickness of 2 mm is used.

  In the present invention, the polyurethane resin foam sheet 14 having a thickness of 1 to 3 mm is carried between the rollers, and then the polyurethane resin foam sheet carried out between the rollers is sliced with the rotary slicing blade 10 and the polishing sheet 15 The remaining sheet 16 is divided. In that case, the space | interval (RC) of the narrowest part between rollers needs to be 70 to 90% of the thickness of the polyurethane resin foam sheet 14 before carrying in between rollers, and is 80 to 85%. Preferably there is. When compressing, the roller on the remaining sheet 16 side is preferably the compression side. Thereby, the thickness accuracy of the polishing sheet 15 which is the target can be further increased.

  Moreover, the distance (HC) from the narrowest part between the said rollers to the front-end | tip of the rotary slice blade 10 needs to be 1 to 2 times the thickness of the polyurethane resin foam sheet 14 before carrying in between rollers. Preferably, it is 1.2 to 1.6 times.

  In the slicing step, it is necessary to slice the polyurethane resin foam sheet 14 while adjusting the temperature of the polyurethane resin foam sheet 14 within the range of the glass transition temperature of the raw material polyurethane resin foam ± 8 ° C.

  The method of adjusting the temperature of the polyurethane resin foam sheet 14 is not particularly limited. For example, the sheet is placed in a forced hot air circulation large dryer (manufactured by Espec Corp., LKS-4B) and heated to a predetermined temperature. A method of adjusting the temperature by providing a heater on the face plate 11 can be mentioned.

  Although the conveyance speed of the polyurethane resin foam sheet 14 is not particularly limited, it is usually about 1 to 3 m / min.

  The thickness of the polishing sheet 15 is preferably 0.5 to 2 mm.

  The thickness variation of the polishing sheet 15 is preferably 100 μm or less. When the thickness variation exceeds 100 μm, a part having a different contact state with respect to the material to be polished is formed, which adversely affects the polishing characteristics. In order to eliminate the thickness variation of the polishing layer, in general, the surface of the polishing layer is dressed with a dresser in which diamond abrasive grains are electrodeposited and fused at the initial stage of polishing. As a result, the dressing time becomes longer and the production efficiency is lowered.

  In order to reduce the thickness variation of the polishing sheet 15, the surface of the polishing sheet sliced to a predetermined thickness may be buffed. When buffing, it is preferable to carry out stepwise with abrasives having different particle sizes.

  The long polishing sheet 15 may be used as it is as a polishing layer, or may be cut into a circle or a rectangle to produce a polishing layer. In the case of a circle, the diameter is about 30 to 150 cm.

  An uneven structure for holding and renewing the slurry may be formed on the surface of the polishing layer. The polishing layer made of foam has many openings on the polishing surface and has the function of holding and updating the slurry. By forming a concavo-convex structure on the polishing surface, the slurry can be held and updated more efficiently. It can be performed well, and destruction of the material to be polished due to adsorption with the material to be polished can be prevented. The concavo-convex structure is not particularly limited as long as it is a shape that holds and renews the slurry. For example, an XY lattice groove, a concentric circular groove, a through hole, a hole that does not penetrate, a polygonal column, a cylinder, a spiral groove, Examples include eccentric circular grooves, radial grooves, and combinations of these grooves. In addition, these uneven structures are generally regular, but in order to make the slurry retention and renewability desirable, the groove pitch, groove width, groove depth, etc. should be changed for each range. Is also possible.

  As a method of forming the concavo-convex structure, for example, a method of machine cutting using a jig such as a tool of a predetermined size, a method of forming a resin by pouring a resin into a mold having a predetermined surface shape, and a predetermined method A method of pressing a resin with a press plate having a surface shape, a method of forming using photolithography, a method of forming using a printing technique, a method of forming by laser light using a carbon dioxide laser, etc. Can be mentioned.

  The polishing pad of the present invention may be a polishing layer alone or a laminate of a polishing layer and another layer (for example, a cushion layer).

  The cushion layer supplements the characteristics of the polishing layer. The cushion layer is necessary in order to achieve both planarity and uniformity in a trade-off relationship in CMP. Planarity refers to the flatness of a pattern portion when a material having fine irregularities generated during pattern formation is polished, and uniformity refers to the uniformity of the entire material to be polished. The planarity is improved by the characteristics of the polishing layer, and the uniformity is improved by the characteristics of the cushion layer. In the polishing pad of the present invention, the cushion layer is preferably softer than the polishing layer.

  Examples of the cushion layer include fiber nonwoven fabrics such as polyester nonwoven fabric, nylon nonwoven fabric, and acrylic nonwoven fabric, resin-impregnated nonwoven fabrics such as polyester nonwoven fabric impregnated with polyurethane, polymer resin foams such as polyurethane foam and polyethylene foam, butadiene rubber, and isoprene. Examples thereof include rubber resins such as rubber and photosensitive resins.

  Examples of means for bonding the polishing layer and the cushion layer include a method of pressing the polishing layer and the cushion layer with a double-sided tape.

  The double-sided tape has a general configuration in which adhesive layers are provided on both sides of a substrate such as a nonwoven fabric or a film. In consideration of preventing the slurry from penetrating into the cushion layer, it is preferable to use a film for the substrate. Examples of the composition of the adhesive layer include rubber adhesives and acrylic adhesives. Considering the content of metal ions, an acrylic adhesive is preferable because the metal ion content is low. In addition, since the composition of the polishing layer and the cushion layer may be different, the composition of each adhesive layer of the double-sided tape can be made different so that the adhesive force of each layer can be optimized.

  The polishing pad of the present invention may be provided with a double-sided tape on the surface to be bonded to the platen. As the double-sided tape, a tape having a general configuration in which an adhesive layer is provided on both surfaces of a base material can be used as described above. As a base material, a nonwoven fabric, a film, etc. are mentioned, for example. In consideration of peeling from the platen after use of the polishing pad, it is preferable to use a film for the substrate. Examples of the composition of the adhesive layer include rubber adhesives and acrylic adhesives. Considering the content of metal ions, an acrylic adhesive is preferable because the metal ion content is low.

  EXAMPLES Hereinafter, although an Example is given and this invention is demonstrated, this invention is not limited to these Examples.

[Measuring method]
(Measurement of average bubble diameter)
A sample obtained by cutting the produced polyurethane resin foam in parallel with a razor blade as thin as possible to a thickness of 1 mm or less was used as a sample. The sample was fixed on a glass slide and observed at 100 times using SEM (S-3500N, Hitachi Science Systems, Ltd.). Using the image analysis software (WinRoof, Mitani Shoji Co., Ltd.) for the obtained image, the total bubble diameter in an arbitrary range was measured, and the average bubble diameter was calculated.

(Measurement of specific gravity)
This was performed according to JIS Z8807-1976. The produced polyurethane resin foam was cut into a 4 cm × 8.5 cm strip (thickness: arbitrary) and used as a sample, which was allowed to stand for 16 hours in an environment of a temperature of 23 ° C. ± 2 ° C. and a humidity of 50% ± 5%. The specific gravity was measured using a hydrometer (manufactured by Sartorius).

(Measurement of hardness)
This was performed according to JIS K-7312. The produced polyurethane resin foam was cut into a size of 5 cm × 5 cm (thickness: arbitrary) as a sample and allowed to stand for 16 hours in an environment of temperature 23 ° C. ± 2 ° C. and humidity 50% ± 5%. At the time of measurement, the samples were overlapped to have a thickness of 10 mm or more. Using a hardness meter (manufactured by Kobunshi Keiki Co., Ltd., Asker D type hardness meter, pressure surface height: 3 mm), the hardness 60 seconds after contacting the pressure surface was measured.

(Measurement of glass transition temperature)
The glass transition temperature of the polyurethane resin foam was measured under the following conditions using a dynamic viscoelasticity measuring apparatus (manufactured by METTLER TOLEDO, DMA861e). The peak temperature of tan δ obtained by the measurement was taken as the glass transition temperature.
Frequency: 1.6Hz
Temperature increase rate: 2 ° C / min
Measurement temperature range: -20 to 100 ° C
Sample shape: length 30mm, width 3mm, thickness 1mm

(Evaluation of unevenness of polishing sheet surface)
The uneven state on the surface of the polishing sheet after slicing was observed visually and touched and evaluated according to the following criteria.
○: There is no unevenness by visual observation, and even when the surface of the sheet is touched by hand, the unevenness is hardly felt.
Δ: There are no irregularities by visual observation, but the irregularities can be clearly seen when the surface of the sheet is touched by hand.
X: Unevenness is clearly seen by visual inspection.

Production Example 1
In a container, 30 parts by weight of polytetramethylene ether glycol (manufactured by Mitsubishi Chemical) having a number average molecular weight of 1000, 55 parts by weight of polycaprolactone triol (manufactured by Daicel Chemical Industries, Plaxel 305), 13 parts by weight of diethylene glycol, 2 parts by weight of trimethylolpropane , 6 parts by weight of a silicon surfactant (manufactured by Toray Dow Corning Silicone, B8443) and 0.03 part by weight of a catalyst (manufactured by Kao, No. 25) are mixed and mixed to prepare a second component (25 ° C.). did. And it stirred vigorously for about 4 minutes so that a bubble might be taken in in a reaction system with the rotation speed of 900 rpm using the stirring blade. Thereafter, 103 parts by weight of carbodiimide-modified MDI (manufactured by Nippon Polyurethane Industry, Millionate MTL, 25 ° C.) as the first component was added to the container (NCO / OH = 1.1) and stirred for about 1 minute to produce a cell dispersed urethane composition. A product was prepared.
The prepared cell-dispersed urethane composition was poured into a pan-shaped open mold (casting container). When the fluidity of the mixed solution disappeared, it was put in an oven and post-cured at 100 ° C. for 16 hours to produce a polyurethane resin foam sheet A (length and width: 1000 mm, thickness: 2 mm).

Production Example 2
In a container, polycaprolactone diol (Daicel Chemical Industries, Plaxel 210N) 62.5 parts by weight, polycaprolactone triol (Daicel Chemical Industries, Plaxel 305) 24.5 parts by weight, diethylene glycol 11 parts by weight, trimethylolpropane 2 2 parts by weight, 6 parts by weight of a silicon surfactant (manufactured by Toray Dow Corning Silicone, B8443), and 0.05 part by weight of a catalyst (manufactured by Kao, No. 25) are mixed and mixed to form a second component (25 ° C.). Was prepared. And it stirred vigorously for about 4 minutes so that a bubble might be taken in in a reaction system with the rotation speed of 900 rpm using the stirring blade. Thereafter, 81 parts by weight of carbodiimide-modified MDI (manufactured by Nippon Polyurethane Industry, Millionate MTL, 25 ° C.) as the first component is added to the container (NCO / OH = 1.1) and stirred for about 1 minute to produce a cell dispersed urethane composition. A product was prepared. Thereafter, a polyurethane resin foam sheet B (1000 mm in length and width, 2 mm in thickness) was produced in the same manner as in Production Example 1.

Example 1
As the slicing device, a hydraulic slicing device (see FIG. 2) manufactured by Murota Manufacturing Co., Ltd. was used. The distance (RC) between the narrowest portions between the rollers was adjusted to 1.8 mm. Moreover, the distance (HC) from the narrowest part between rollers to the front-end | tip of a rotary slice blade was adjusted to 2 mm. The rotating slice blade has a circumferential length of 8 m, a blade width of 10 cm, a tip blade width of 8 mm, and a blade thickness of 2 mm. The produced polyurethane resin foam sheet A is heated to 70 ° C. in a forced hot air circulating large dryer (manufactured by ESPEC Co., Ltd., LKS-4B). did. And the said sheet | seat A was carried in between rollers with the conveyance speed of 2 m / min, and the sheet | seat A carried out from between rollers was sliced with the rotary slice blade, and was divided | segmented into the grinding | polishing sheet and the remainder sheet | seat. The slicing process could be carried out satisfactorily, and an abrasive sheet free from wrinkles and irregularities and having a small thickness variation was obtained. Then, the polishing sheet is punched out with a diameter of 60 cm, and a concentric groove having a groove width of 0.25 mm, a groove pitch of 1.50 mm, and a groove depth of 0.40 mm is formed on the polishing surface using a groove processing machine (manufactured by Techno). Processing was performed to prepare a polishing layer.
A double-sided tape (manufactured by Sekisui Chemical Co., Ltd., double tack tape) was attached to the surface opposite to the buffed surface of the prepared polishing layer using a laminator. Furthermore, a corona-treated cushion layer (manufactured by Toray Industries, Inc., polyethylene foam, Torepef, thickness 0.8 mm) was bonded to the double-sided tape using a laminator. Further, a double-sided tape was attached to the other surface of the cushion layer using a laminator to prepare a polishing pad.

Examples 2-7
Example 1 except that the slicing step was performed at the interval (RC) of the narrowest portion between the rollers shown in Table 1, the distance (HC) from the narrowest portion between the rollers to the tip of the rotary slicing blade, and the sheet temperature. A polishing pad was prepared in the same manner as described above. In all the examples, the slicing step could be carried out satisfactorily, and an abrasive sheet having no wrinkles or irregularities and small thickness variation was obtained.

Example 8
The polyurethane resin foam sheet B is used instead of the polyurethane resin foam sheet A, and the distance (RC) between the narrowest portions between the rollers shown in Table 1 is the distance from the narrowest portion between the rollers to the tip of the rotary slice blade. A polishing pad was prepared in the same manner as in Example 1 except that the slicing step was performed at (HC) and the sheet temperature. The slicing process could be carried out satisfactorily, and an abrasive sheet free from wrinkles and irregularities and having a small thickness variation was obtained.

Comparative Examples 1-6
Example 1 except that the slicing step was performed at the interval (RC) of the narrowest portion between the rollers shown in Table 1, the distance (HC) from the narrowest portion between the rollers to the tip of the rotary slicing blade, and the sheet temperature. A polishing pad was prepared in the same manner as described above. In all the comparative examples, a problem occurred in the slicing process, and the obtained polishing sheet had wrinkles and irregularities, and the thickness variation was large.

Comparative Example 7
The polyurethane resin foam sheet B is used instead of the polyurethane resin foam sheet A, and the distance (RC) between the narrowest portions between the rollers shown in Table 1 is the distance from the narrowest portion between the rollers to the tip of the rotary slice blade. A polishing pad was prepared in the same manner as in Example 1 except that the slicing step was performed at (HC) and the sheet temperature. A problem occurred in the slicing process, and the obtained polishing sheet had wrinkles and irregularities, resulting in large variations in thickness.

Schematic configuration diagram showing an example of a polishing apparatus used in CMP polishing Schematic showing the slicing process of the present invention

Explanation of symbols

1: Polishing pad (polishing layer)
2: Polishing surface plate 3: Abrasive (slurry)
4: Material to be polished (glass substrate)
5: Support base (polishing head)
6, 7: Rotating shaft 8: Upper feed roller 9: Lower feed roller 10: Rotating slice blade 11: Top plate (guide plate)
12: Triangular plate 13: Slicing blade fixing plate 14: Polyurethane resin foam sheet 15: Polishing sheet 16: Remaining sheet

Claims (2)

In the manufacturing method of the polishing pad including the slicing step of slicing the polymer foam sheet to prepare the polishing sheet,
The slicing step uses a slicing apparatus having a pair of upper and lower feed rollers and an endless belt-like rotating slice blade, and carries a polymer foam sheet having a thickness of 1 to 3 mm between the rollers, Thereafter, the step of slicing the polymer foam sheet carried out between the rollers with the rotating slice blade,
The interval of the narrowest portion between the rollers is 70 to 90% of the thickness of the polymer foam sheet before being carried between the rollers,
The distance from the narrowest part between the rollers to the tip of the rotary slice blade is 1 to 2 times the thickness of the polymer foam sheet before being carried between the rollers, and the polymer foam sheet A method for producing a polishing pad, characterized by slicing while adjusting the temperature within a range of glass transition temperature ± 8 ° C. of a polymer foam as a raw material. A polishing pad produced by the method according to claim 1.

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