Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B24—GRINDING; POLISHING
  • B24B—MACHINES, DEVICES, OR PROCESSES FOR GRINDING OR POLISHING; DRESSING OR CONDITIONING OF ABRADING SURFACES; FEEDING OF GRINDING, POLISHING, OR LAPPING AGENTS
  • B24B37/00—Lapping machines or devices; Accessories
  • B24B37/11—Lapping tools
  • B24B37/20—Lapping pads for working plane surfaces
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B24—GRINDING; POLISHING
  • B24D—TOOLS FOR GRINDING, BUFFING OR SHARPENING
  • B24D18/00—Manufacture of grinding tools or other grinding devices, e.g. wheels, not otherwise provided for
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
  • B29C44/00—Shaping by internal pressure generated in the material, e.g. swelling or foaming ; Producing porous or cellular expanded plastics articles
  • B29C44/20—Shaping by internal pressure generated in the material, e.g. swelling or foaming ; Producing porous or cellular expanded plastics articles for articles of indefinite length
  • B29C44/32—Incorporating or moulding on preformed parts, e.g. linings, inserts or reinforcements
  • B29C44/321—Incorporating or moulding on preformed parts, e.g. linings, inserts or reinforcements the preformed part being a lining, e.g. a film or a support lining
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
  • B29C44/00—Shaping by internal pressure generated in the material, e.g. swelling or foaming ; Producing porous or cellular expanded plastics articles
  • B29C44/20—Shaping by internal pressure generated in the material, e.g. swelling or foaming ; Producing porous or cellular expanded plastics articles for articles of indefinite length
  • B29C44/32—Incorporating or moulding on preformed parts, e.g. linings, inserts or reinforcements
  • B29C44/326—Joining the preformed parts, e.g. to make flat or profiled sandwich laminates
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
  • B29C44/00—Shaping by internal pressure generated in the material, e.g. swelling or foaming ; Producing porous or cellular expanded plastics articles
  • B29C44/20—Shaping by internal pressure generated in the material, e.g. swelling or foaming ; Producing porous or cellular expanded plastics articles for articles of indefinite length
  • B29C44/32—Incorporating or moulding on preformed parts, e.g. linings, inserts or reinforcements
  • B29C44/332—Incorporating or moulding on preformed parts, e.g. linings, inserts or reinforcements the preformed parts being three-dimensional structures
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
  • C08G18/00—Polymeric products of isocyanates or isothiocyanates
  • C08G18/06—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen
  • C08G18/08—Processes
  • C08G18/10—Prepolymer processes involving reaction of isocyanates or isothiocyanates with compounds having active hydrogen in a first reaction step
  • C08G18/12—Prepolymer processes involving reaction of isocyanates or isothiocyanates with compounds having active hydrogen in a first reaction step using two or more compounds having active hydrogen in the first polymerisation step
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
  • C08G18/00—Polymeric products of isocyanates or isothiocyanates
  • C08G18/06—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen
  • C08G18/28—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen characterised by the compounds used containing active hydrogen
  • C08G18/40—High-molecular-weight compounds
  • C08G18/48—Polyethers
  • C08G18/4854—Polyethers containing oxyalkylene groups having four carbon atoms in the alkylene group
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
  • C08G18/00—Polymeric products of isocyanates or isothiocyanates
  • C08G18/06—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen
  • C08G18/70—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen characterised by the isocyanates or isothiocyanates used
  • C08G18/72—Polyisocyanates or polyisothiocyanates
  • C08G18/721—Two or more polyisocyanates not provided for in one single group C08G18/73 - C08G18/80
  • C08G18/724—Combination of aromatic polyisocyanates with (cyclo)aliphatic polyisocyanates
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
  • C08G18/00—Polymeric products of isocyanates or isothiocyanates
  • C08G18/06—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen
  • C08G18/70—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen characterised by the isocyanates or isothiocyanates used
  • C08G18/72—Polyisocyanates or polyisothiocyanates
  • C08G18/74—Polyisocyanates or polyisothiocyanates cyclic
  • C08G18/75—Polyisocyanates or polyisothiocyanates cyclic cycloaliphatic
  • C08G18/758—Polyisocyanates or polyisothiocyanates cyclic cycloaliphatic containing two or more cycloaliphatic rings
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
  • C08G18/00—Polymeric products of isocyanates or isothiocyanates
  • C08G18/06—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen
  • C08G18/70—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen characterised by the isocyanates or isothiocyanates used
  • C08G18/72—Polyisocyanates or polyisothiocyanates
  • C08G18/74—Polyisocyanates or polyisothiocyanates cyclic
  • C08G18/76—Polyisocyanates or polyisothiocyanates cyclic aromatic
  • C08G18/7614—Polyisocyanates or polyisothiocyanates cyclic aromatic containing only one aromatic ring
  • C08G18/7621—Polyisocyanates or polyisothiocyanates cyclic aromatic containing only one aromatic ring being toluene diisocyanate including isomer mixtures
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
  • C08G2110/00—Foam properties
  • C08G2110/0025—Foam properties rigid

Definitions

• the present invention relates to 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.
• TECHNICAL FIELD The present invention relates to a laminated polishing pad that can be processed stably and with high polishing efficiency, and a method for manufacturing the same.
• the laminated polishing pad of the present invention flattens a silicon wafer and a device on which an oxide layer, a metal layer, etc. are formed before laminating and forming these oxide layers and metal layers. It is suitably used in the process. Background art
• a conductive film is formed on the wafer surface and a wiring layer is formed by photolithography, etching, etc., and an interlayer insulating film is formed on the wiring layer. These steps cause irregularities such as metal conductors and insulators on the wafer surface.
• the power of miniaturization of wiring and multilayer wiring for the purpose of increasing the density of semiconductor integrated circuits has been accompanied by the importance of a technique for flattening the unevenness of the wafer surface.
• CMP chemical mechanical force polishing
• a polishing apparatus generally used in CMP includes a polishing surface plate 2 that supports a polishing pad 1 and a support table (polishing) that supports a material to be polished (semiconductor wafer) 4.
• 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 arranged so that the polishing pad 1 and the material to be polished 4 that are supported respectively face each other, and are provided with rotating shafts 6 and 7, respectively.
• a pressure mechanism for pressing the workpiece 4 against the polishing pad 1 is provided on the support base 5 side.
• such a polishing pad has 1) a method in which a resin material is poured into a mold to produce a resin block, and the resin block is sliced with a slicer.
• Patent Document 1 manufactures a polishing pad by a reaction injection molding method.
• Patent Document 3 a method of continuously producing a polyurethane / polyurea abrasive sheet material has been proposed in order to prevent variations in hardness, bubble size, and the like resulting from a batch production method.
• a polyurethane raw material is mixed with a fine powder having a particle size of 300 m or less or an organic foaming agent, and the mixture is discharged between a pair of endless track belts and cast. Thereafter, a polymerization reaction of the mixture is performed by a heating means, and the formed sheet-like molded product is separated from the face belt to obtain an abrasive sheet material.
• a groove for holding and renewing slurry is usually provided on the polishing surface of the polishing pad that comes into contact with the material to be polished.
• a polishing pad made of foam it has many openings on the polishing surface and has the function of holding and renewing the slurry. Renewal can be performed efficiently, and destruction of the material to be polished due to adsorption with the material to be polished can be prevented.
• a polyurethane foam sheet is generally used as a polishing pad used for high-precision polishing.
• the polyurethane foam sheet is excellent in local flattening ability! /,
• a soft and cushion layer is separately provided on the back surface of the polyurethane foam sheet and is used for polishing as a laminated polishing pad.
• the followings have been developed as the laminated polishing node.
• a relatively hard first layer and a relatively soft second layer are laminated, and polishing of the first layer
• a polishing pad having a surface with grooves having a predetermined pitch or protrusions having a predetermined shape is disclosed (Patent Document 4).
• the first sheet-like member having elasticity and having irregularities formed on the surface thereof, and the surface of the first sheet-like member provided with the irregularities are opposed to the polished surface of the substrate to be processed.
• An abrasive cloth having a second sheet-like part having a surface to be used is disclosed (Patent Document 5).
• a polishing pad that includes a polishing layer and a support layer that is laminated on one surface of the polishing layer and is a foam having a higher compressibility than the polishing layer (Patent Document 6).
• the conventional laminated polishing pad is manufactured by bonding the polishing layer and the cushion layer with a double-sided tape (adhesive layer), the polishing layer and the cushion layer are bonded during polishing.
• the slurry penetrated between them and the adhesive strength of the double-sided tape was weakened.
• the polishing layer and the cushion layer were peeled off.
• the clogging easily occurs in the slurry, and the clogging and polishing debris are accumulated in the grooves, and the polishing rate decreases and becomes unstable.
• the flatness and in-plane uniformity of the abrasive were reduced.
• Patent Document 1 Japanese Patent Application Laid-Open No. 2004-42189
• Patent Document 2 Japanese Patent Laid-Open No. 2003-220550
• Patent Document 3 Japanese Unexamined Patent Application Publication No. 2004-169038
• Patent Document 4 Japanese Unexamined Patent Publication No. 2003-53657
• Patent Document 5 Japanese Patent Laid-Open No. 10-329005
• Patent Document 6 Japanese Unexamined Patent Application Publication No. 2004-25407
• An object of the present invention is to provide a method for producing a laminated polishing pad with few production steps and excellent productivity. Furthermore, the present invention provides a method for producing a laminated polishing pad that can be prevented from peeling between a polishing layer and a cushion layer and that can prevent clogging of a groove due to a slurry, and a laminated polishing pad produced by the method. For the purpose. It is another object of the present invention to provide a method for manufacturing a semiconductor device using the stacked polishing pad.
• the method for producing a laminated polishing pad according to the first aspect of the present invention comprises a step of preparing a cell-dispersed urethane composition by a mechano-calf froth method, and continuously delivering a cell-dispersed urethane composition onto the cushion layer while delivering the cushion layer.
• a process for producing a long laminated sheet by forming a polishing layer having polyurethane foam strength by curing the cell-dispersed urethane composition while uniformly adjusting the thickness, and cutting the long laminated sheet The process of carrying out is included.
• a laminated polishing pad composed of a polishing layer and a cushion layer can be continuously manufactured, and a step of bonding the polishing layer and the cushion layer can be omitted.
• the laminated polishing pad can be manufactured with high productivity. Since the laminated polishing pad obtained by the production method directly laminates the polishing layer and the cushion layer without using a double-sided tape (adhesive layer), the polishing layer and the cushion layer peel off during polishing. There is an advantage of not being separated.
• the method for producing a laminated polishing pad of the second aspect of the present invention includes a step of preparing a cell-dispersed urethane composition by a mechano-calf froth method, and a cushion layer having a convex portion on a surface in contact with the polishing layer.
• polishing layer having a polyurethane foam strength to produce a long laminated sheet, to cut the long laminated sheet, and to be positioned between the protrusions on the surface of the cushion layer. Forming a concave structure on the surface of the polishing layer.
• a laminated polishing pad composed of a polishing layer and a cushion layer can be continuously manufactured, and further, the step of bonding the polishing layer and the cushion layer can be omitted. Therefore, the laminated polishing pad can be manufactured with high productivity. Furthermore, the laminated polishing pad produced by the above method does not peel off between the polishing layer and the cushion layer, and is less likely to be clogged with grooves due to slurry, polishing scraps, or the like. The reason why groove clogging occurs when a conventional multilayer polishing pad is used is as follows. available.
• the conventional laminated polishing pad has a structure in which a polishing layer 8 having a concave structure 10 on the polishing surface side is laminated on a flat cushion layer 9.
• the concave structure is greatly deformed by the pressure 13 and the opening becomes narrow.
• slurries and polishing debris are clogged in the concave structure, making it impossible to efficiently hold and renew the slurry, reducing the polishing speed and destabilizing it, and flattening the surface to be polished or even within the surface. It is considered that the performance will be reduced.
• the laminated polishing pad obtained by the second production method of the present invention has a special structure as shown in FIG.
• the concave portion 12 is provided on the back surface of the polishing layer 8
• the convex portion 11 is provided on the surface of the cushion layer 9 and engaged (contacted)
• the concave structure 10 on the polishing surface side of the polishing layer is further provided on the cushion layer surface.
• the polishing layer and the cushion layer are in close contact with each other without any other member such as a double-sided tape (adhesive layer).
• the slurry can be prevented from entering the interface between the polishing layer and the cushion layer.
• the adhesive force at the interface is not weakened by the slurry because an adhesive member such as a double-sided tape (adhesive layer) is not used. Therefore, it is possible to effectively prevent the polishing layer and the cushion layer from peeling off.
• the height (H) of the convex portion on the cushion layer surface is preferably adjusted to 0.05 to 0.9 times the thickness (h) of the polishing layer. More preferably, it is 0.1 to 0.6 times.
• the height of the convex portion is less than 0.05 times the thickness of the polishing layer, the amount of deformation of the convex portion becomes insufficient, so that the pressure from the material to be polished is sufficiently absorbed by the deformation of the convex portion. It becomes impossible.
• the deformation of the opening of the concave structure on the polishing surface side becomes large, and the slurry There is a tendency that polishing scraps and the like are easily clogged in the concave structure.
• the elastic modulus of the polishing layer decreases and the flatness characteristic tends to decrease.
• the difference (h ⁇ H) between the thickness (h) of the polishing layer and the height (H) of the protrusion on the cushion layer surface is preferably adjusted to 0.2 mm or more, more preferably. 0.4 mm or more
• the width (W) of the convex portion on the surface of the cushion layer is preferably adjusted to 1 to 30 times the width (w) of the concave structure on the surface of the polishing layer, more preferably 3 to 15 times.
• the width of the convex portion is less than 1 times the width of the concave structure on the surface of the polishing layer, the pressure of the polishing target cannot be sufficiently absorbed by the deformation of the convex portion.
• the deformation of the opening portion of the concave structure on the polishing surface side increases, and slurry and polishing debris tend to clog the concave structure.
• the width of the convex portion exceeds 30 times the width of the concave structure on the surface of the polishing layer, the elastic modulus of the polishing layer tends to decrease and flatness characteristics tend to decrease.
• the width (w) of the island part of the polishing layer and the width of the convex part on the surface of the cushion layer W, however, there are multiple convex parts in one island part
• the difference (w ⁇ W) from the total width is adjusted to 0.5 mm or more.
• it is 0.75 mm or more.
• the present invention also relates to a laminated polishing pad produced by the above method, and a method for producing a semiconductor device including a step of polishing the surface of a semiconductor wafer using the laminated polishing pad.
• FIG. 1 is a schematic configuration diagram showing an example of a polishing apparatus used in CMP polishing.
• FIG. 3 is a schematic configuration diagram of a laminated polishing pad according to the present invention.
• FIG. 4 is a schematic view showing the production process of the laminated polishing pad of the present invention.
• FIG. 5 is a schematic configuration diagram of another laminated polishing pad of the present invention.
• FIG. 6 is a schematic configuration diagram of another laminated polishing pad according to the present invention.
• FIG. 7 is a schematic configuration diagram of another laminated polishing pad according to the present invention.
• FIG. 8 is a schematic configuration diagram of another laminated polishing pad of the present invention.
• the first method for producing a laminated polishing pad of the present invention comprises a step of preparing a cell-dispersed urethane composition by a mecha-calfloss method, and continuously delivering a cell-dispersed urethane composition onto the cushion layer while feeding the cushion layer.
• the second method for producing a laminated polishing pad of the present invention includes a step of preparing a cell-dispersed urethane composition by a mechanical calfloss method, and a cushion layer having a convex portion on a surface in contact with the polishing layer.
• To form a polishing layer having a polyurethane foam strength to produce a long laminated sheet to cut the long laminated sheet, and to be positioned between the protrusions on the surface of the cushion layer. Forming a concave structure on the surface of the polishing layer.
• the polishing layer in the present invention also has a polyurethane foam having fine bubbles.
• Polyurethane is a preferred material for forming the polishing layer because it is excellent in abrasion resistance, and a polymer having desired physical properties can be easily obtained by changing the raw material composition.
• the polyurethane also has an isocyanate component, a polyol component (high molecular weight polyol component, low molecular weight polyol component), and chain extender power.
• the isocyanate component compounds known in the field of polyurethane can be used without particular limitation.
• the isocyanate component includes 2,4 toluene diisocyanate, 2,6 toluene diisocyanate, 2,2'-dimethanemethane diisocyanate, 2,4'-diphenylmethane diisocyanate, 4,4'-di-methanemethane diisocyanate, 1,5-naphthalene diisocyanate, p-phenylene diisocyanate, m-phenylene diisocyanate, p-xylylene diisocyanate, m-xylylene Aromatic diisocyanates such as range isocyanates, ethylene diisocyanates, 2, 2, 4 trimethylhexamethylene diisocyanates, aliphatic diisocyanates such as 1,6 hexamethylene diisocyanates, 1,4-cyclo Hexane diisocyanate, 4,4'-dicy
• the isocyanate component in addition to the above-mentioned diisocyanate compound, a polyfunctional polyisocyanate compound having three or more functions can be used.
• a polyfunctional polyisocyanate compound having three or more functions.
• a multifunctional isocyanate compound a series of diisocyanate duct compounds are commercially available as Desmodur N (manufactured by Bayer) and trade name Deuranate (manufactured by Asahi Kasei Kogyo).
• isocyanate components it is preferable to use an aromatic diisocyanate and an alicyclic diisocyanate in combination, and it is particularly preferable to use toluene diisocyanate and dicyclohexylmethane diisocyanate in combination!
• Examples of the high molecular weight polyol component include polyether polyols typified by polytetramethylene ether glycol, polyester polyols typified by polybutylene adipate, polyester glycols such as poly-force prolataton polyol, and poly-force prolatathone.
• polycarbonate polyols obtained by transesterification with aryl carbonate may be used alone or in combination of two or more.
• the number average molecular weight of the high molecular weight polyol component is not particularly limited, but it is preferably 500 to 2000 from the viewpoint of the elastic properties of the obtained polyurethane resin.
• the number average molecular weight is less than 500, polyurethane resin using the number average molecular weight does not have sufficient elastic properties and becomes a brittle polymer. Therefore, the polishing pad manufactured from this polyurethane resin becomes too hard and causes scratches on the wafer surface. Moreover, since it is easy to wear, it is not preferable from the viewpoint of the node life.
• the number average molecular weight exceeds 2000 the polyurethane resin using the number average molecular weight becomes too soft, and the polishing layer produced from the polyurethane resin tends to be inferior in flatness properties.
• a low molecular weight polyol component such as 1,4-cyclohexanedimethanol, 3-methyl-1,5-pentanediol, diethylene glycol, triethylene glycol, 1,4 bis (2 hydroxyethoxy) benzene.
• Low molecular weight polyamine components such as ethylenediamine, tolylenediamine, diphenylmethanediamine, and diethylenetriamine may be used.
• the (number average) molecular weight of the low molecular weight polyol component and the low molecular weight polyamine component is less than 500, preferably Is less than 250.
• the ratio of the high molecular weight polyol to the low molecular weight polyol in the polyol component is determined by the properties required for the polishing layer produced therefrom.
• a chain extender is used for curing the prepolymer.
• the chain extender is an organic compound having at least two or more active hydrogen groups. Examples of the active hydrogen group include a hydroxyl group, a primary or secondary amino group, and a thiol group (SH).
• the ratio of the isocyanate component, the polyol component, and the chain extender in the present invention can be variously changed depending on the molecular weight of each, the desired physical properties of the polishing layer, and the like.
• the number of isocyanate groups in 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 L20. More preferably, it is 0.99 ⁇ : L15.
• the polyurethane foam can be produced by either the prepolymer method or the one-shot method.
• An isocyanate-terminated polymer is synthesized beforehand from an isocyanate component and a polyol component, and this is reacted with a chain extender.
• Prebolimer legal force Tan has excellent physical properties and is suitable.
• an isocyanate-terminated prepolymer having a molecular weight of about 800 to 5000 is preferable because of its excellent processability and physical properties.
• the cushion layer in the present invention supplements the characteristics of the polishing layer.
• the cushion layer is necessary in order to achieve both planarity and formality, which are in a trade-off relationship, in CMP.
• Planarity refers to the flatness of a pattern portion when a material to be polished having minute irregularities generated during pattern formation is polished
• formality refers to the uniformity of the entire material to be polished.
• the planarity is improved by the characteristics of the polishing layer, and the formability is improved by the characteristics of the tack layer.
• the cushion layer is softer than the polishing layer.
• the material for forming the cushion layer is not particularly limited as long as it is softer than the polishing layer.
• fiber nonwoven fabrics such as polyester nonwoven fabrics, nylon nonwoven fabrics, acrylic nonwoven fabrics, etc .;
• rubber-based resin such as ren rubber, and photosensitive resin.
• the thickness of the cushion layer is not particularly limited, but is usually about 0.5 to 1.5 mm, and is 0.5 to 1. Omm.
• the hardness of the cushion layer is preferably 10 to 75 degrees in terms of Asker A hardness, more preferably 20 to 65 degrees. Outside the above range, the uniformity (in-plane uniformity) of the material to be polished tends to decrease.
• FIG. 4 is a schematic view showing the production process of the laminated polishing pad of the present invention.
• the cell-dispersed urethane composition 14 is prepared by the mecha-calfloss method.
• the mecha-calf flow method is a method in which raw material components are placed in the mixing chamber of the mixing head 15, mixed with a non-reactive gas, and mixed and stirred with a mixer such as an Oaks mixer to make the non-reactive gas in a fine bubble state. In the raw material mixture.
• the mechanical calfloss method is a preferable method because the density of the polyurethane foam can be easily adjusted by adjusting the mixing amount of the non-reactive gas.
• the non-reactive gas used to form microbubbles is not flammable! Specific examples of preference are soot, nitrogen, oxygen, carbon dioxide, rare gases such as helium and argon, and mixed gases thereof. The use of air that has been dried to remove moisture is most preferred in terms of cost. .
• a silicone surfactant that does not have an active hydrogen group and is a copolymer of polyalkylsiloxane and polyether is added to the raw material components. It is preferable to keep it.
• suitable silicon surfactants include SH-190, SH-192 (manufactured by Toray Dow Co., Ltd. Silicone), L-5340 (manufactured by Nippon Yuka Co., Ltd.), and the like.
• the addition amount of the silicone-based surfactant is preferably 0.05% by weight or more and less than 5% by weight in the polyurethane foam.
• the amount of the silicon-based surfactant is less than 0.05% by weight, a fine-bubble foam tends to be not obtained.
• the content is 5% by weight or more, the number of bubbles in the foam is too large, and it is difficult to obtain a polyurethane foam with high hardness.
• stabilizers such as antioxidants, lubricants, pigments, fillers, antistatic agents, and other additives may be added.
• a known catalyst for promoting a polyurethane reaction such as a tertiary amine may be used.
• the type and addition amount of the catalyst are appropriately selected in consideration of the flow time after discharging the cell-dispersed urethane composition onto the cushion layer.
• the cushion layer 9 moves on the conveyor 16, and the cell dispersed urethane composition 14 is continuously discharged onto the cushion layer 9 from the discharge nozzle of the mixing head 15.
• the moving speed of the cushion layer 9 and the discharge amount of the cell dispersed urethane composition 14 are appropriately adjusted in consideration of the thickness of the polishing layer.
• the foam-dispersed urethane composition is cured while the thickness is uniformly adjusted to form a polishing layer having a polyurethane foam strength, thereby producing a long laminated sheet 17.
• means for uniformly adjusting the thickness include rolls 18 such as nip rolls and coater rolls, doctor blades, and the like.
• the face material 22 may be used to adjust the thickness uniformly.
• distribution urethane composition is performed by allowing the inside of the heating oven provided on the conveyor to pass through after adjusting thickness uniformly, for example.
• Caro Heat temperature is about 40-100 ° C, and heating time is about 5-10 minutes. Heating and post-curing the foam-dispersed urethane composition that has reacted until it stops flowing It has the effect of improving the physical properties of the foam.
• the average cell diameter of the polyurethane foam is preferably 30 to 80 m, more preferably 30 to 60 m. 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 obtained long laminated sheet 17 is cut into a predetermined shape by a cutting machine 19 to form a laminated polishing sheet 20.
• the laminated polishing sheet 20 then becomes a laminated polishing pad 1 through several steps.
• the thickness of the polishing layer is not particularly limited, but is usually about 0.8 to 4 mm, 1.
• the specific gravity of the polishing layer is preferably 0.5 to 1.0.
• the specific gravity is less than 0.5, the strength of the surface of the polishing layer is lowered, and the planarity (flatness) of the material to be polished tends to deteriorate.
• the ratio is larger than 1.0, the number of fine bubbles on the surface of the polishing layer is reduced, and the flatness characteristic is good, but the polishing rate tends to be poor.
• the hardness of the polishing layer is preferably 45 to 65 degrees as measured by a Asker D hardness meter.
• the thickness variation of the polishing layer is preferably 100 ⁇ m or less.
• the polishing layer has a large undulation, and there are parts with different contact conditions with the material to be polished, which adversely affects the polishing characteristics.
• the ability to dress the surface of the polishing layer using a dresser in which diamond abrasive grains are electrodeposited and fused in the initial stage of polishing exceeds the above range. As a result, the dressing time becomes longer and the production efficiency is lowered.
• a method of suppressing the thickness variation of the polishing layer a method of knotting the surface of the long laminated sheet 17 with a puffing machine can be mentioned. Further, after the long laminated sheet 17 is cut, the surface of the laminated polishing sheet 20 may be puffed to suppress the thickness variation of the polishing layer. In addition, it is preferable to perform stepwise with abrasives having different particle sizes.
• a polishing member that contacts the material to be polished of the laminated polishing pad.
• the polished surface preferably has an uneven structure for holding and renewing the slurry.
• the polishing layer which also has foam strength, has many openings on the polishing surface and has the function of holding and updating the slurry, but by forming an uneven structure on the polishing surface, the holding and updating of the slurry is further reduced.
• the uneven structure is not particularly limited as long as it holds and renews the slurry.
• XY lattice groove concentric circular groove, through hole, non-through hole, polygonal column, cylinder, spiral groove, eccentricity Examples include circular grooves, radial grooves, and combinations of these grooves.
• these uneven structures are generally regular, but in order to make slurry retention and renewability desirable, the groove pitch, groove width, groove depth, etc. should be changed for each range. Is also possible.
• the method for producing the concavo-convex structure is not particularly limited.
• a mechanical cutting method using a jig such as a tool of a predetermined size, a press plate having a predetermined surface shape, And the like, a method of producing by photolithography, a method of producing by using a printing technique, a method of producing by laser light using a carbon dioxide laser or the like.
• the second laminated polishing pad of the present invention a method for producing the second laminated polishing pad of the present invention will be described. Basically, it is the same method as the manufacturing method of the first laminated polishing pad, except that 1) a long cushion layer having a convex portion on the surface in contact with the polishing layer is used, and the convexity of the cushion layer is used. 2) A concave structure is formed on the surface of the polishing layer so as to be located between the convex portions of the cushion layer surface, The point is different.
• a long cushion layer having a convex portion on the surface in contact with the polishing layer can be obtained by, for example, 1) mechanically grinding the surface of the long sheet cushion layer using a tool such as a cutting tool.
• a method of forming a convex portion 2) a method of heating and pressing the surface of a long sheet-like cushion layer with a press plate having a predetermined surface shape, 3) a method of forming a convex portion using a photolithographic printing method, 4)
• a method of forming a convex portion with a laser beam using a carbon dioxide laser or the like can be mentioned.
• the convex portion may be continuously formed by using the concave / convex roll 21 before discharging the cell dispersed urethane yarn and the composite 14.
• the shape of the projection is not particularly limited, and for example, a rectangle as shown in FIG. 5 or a circle as shown in FIG. Examples include arc shapes and triangle shapes as shown in FIG. Further, as shown in FIG. 8, two or more convex portions on the surface of the cushion layer may be provided between adjacent concave structures on the surface of the polishing layer (within one island portion).
• the thickness of the cushion layer (excluding the convex portion) is preferably 0.5 to 1.5 mm, more preferably 0.5 to Lmm.
• a bubble dispersion urethane is formed on the surface of the cushion layer having the convex portions.
• the composition is continuously discharged using a press plate having a predetermined surface shape (a shape for forming a concave structure on the polished surface) after the thickness of the composition is uniformly adjusted.
• a press plate having a predetermined surface shape (a shape for forming a concave structure on the polished surface) after the thickness of the composition is uniformly adjusted.
• An example is a method in which a product is pressed and then the composition is heated to react and cure.
• the press plate is aligned during pressing so that a concave structure on the polishing layer surface is formed between the convex portions on the cushion layer surface.
• a concave structure may be formed on the surface of the polishing layer.
• the method of forming the concave structure is not particularly limited. For example, a method of mechanical cutting using a jig of a predetermined size, a method of forming using photolithography, or a printing method is used. And a method of forming with a laser beam using a carbon dioxide laser or the like.
• the laminated polishing pad of the present invention may be provided with a double-sided tape on the side of the cushion layer that adheres to the platen.
• a double-sided tape one having a general configuration in which an adhesive layer is provided on both sides of a substrate can be used.
• the substrate include nonwoven fabric and film.
• a film In consideration of separation of the platen force after use of the laminated polishing pad, it is preferable to use a film as the base material.
• the composition of the adhesive layer include rubber adhesives and acrylic adhesives. Considering the metal ion content, acrylic adhesives are preferred due to their low metal ion content.
• the semiconductor device is manufactured through a step of polishing the surface of the semiconductor wafer using the laminated polishing pad.
• a semiconductor wafer is generally a laminate of a wiring metal and an oxide film on a silicon wafer.
• the method and apparatus for polishing the semiconductor wafer are not particularly limited.
• a polishing surface plate 2 that supports a laminated polishing pad 1 and a semiconductor wafer.
• C It is performed using a polishing table equipped with a support table (polishing head) 5 for supporting 4, a backing material for performing uniform pressure on the wafer, and a polishing agent 3 supply mechanism.
• the laminated polishing node 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 table 5 are arranged so that the laminated polishing pad 1 and the semiconductor wafer 4 supported on each of the polishing surface plate 2 and the support table 5 face each other, and are provided with rotating shafts 6 and 7, respectively.
• a pressure mechanism for pressing the semiconductor wafer 4 against the laminated polishing pad 1 is provided on the support base 5 side.
• the semiconductor wafer 4 is pressed against the laminated polishing node 1 while rotating the polishing surface plate 2 and the support base 5, and polishing is performed while supplying slurry.
• the flow rate of the slurry, polishing load, polishing platen rotation speed, and wafer rotation speed are not particularly limited, and are adjusted as appropriate.
• the protruding portion of the surface of the semiconductor wafer 4 is removed and polished flat. Thereafter, semiconductor devices are manufactured by dicing, bonding, knocking, and the like.
• the semiconductor device is used for an arithmetic processing device, a memory, and the like.
• the number average molecular weight was measured by GPC (gel “permeation” chromatography) and converted by standard polystyrene.
• the prepared polishing layer was cut as thin as possible to a thickness of 1 mm or less in parallel with a microtome cutter, and used as a sample for measuring the average cell diameter.
• the sample was fixed on a slide glass, and the total bubble diameter in an arbitrary 0.2 mm X O.2 mm range was measured using an image processing apparatus (Toyobo, Image Analyzer V10), and the average bubble diameter was calculated.
• the prepared cushion layer and polishing layer were cut into 4cm x 8.5cm strips (thickness: optional) as a sample for measuring specific gravity, in an environment with a temperature of 23 ° C ⁇ 2 ° C and humidity of 50% ⁇ 5%. It was left for 16 hours. The specific gravity was measured using a hydrometer (manufactured by Sartorius).
• the prepared polishing layer was cut to a size of 2cm x 2cm (thickness: arbitrary) and used as a sample for hardness measurement, and left for 16 hours in an environment of temperature 23 ° C ⁇ 2 ° C, humidity 50%, 5% did. At the time of measurement, the samples were overlapped to a thickness of 6 mm or more. The hardness was measured using a hardness meter (manufactured by Kobunshi Keiki Co., Ltd., Asker D-type hardness meter).
• SPP600S (Okamoto Machine Tool Co., Ltd.) was used as the polishing device, and the polishing characteristics were evaluated using the produced laminated polishing pad.
• the initial polishing rate was calculated from the time at which a thermal oxide film of 1 ⁇ m formed on an 8-inch silicon wafer was polished about 0.5 ⁇ m.
• An interferometric film thickness measuring device (manufactured by Otsuka Electronics Co., Ltd.) was used for measuring the thickness of the oxide film.
• silica slurry (SS12 Cabot) was added as a slurry at a flow rate of 150 ml / min during polishing.
• the polishing load was 350 g / cm 2
• the polishing platen rotation speed was 35 rpm
• the wafer rotation speed was 30 rpm.
• TEOS oxide film
• a 5 m patterned wafer was fabricated. This wafer was polished under the above-mentioned polishing conditions and evaluated by measuring the amount of scraping at the bottom of the 25 ⁇ m space when the global step was 2000A or less. The flatness is better as the value is smaller.
• the in-plane uniformity was evaluated by polishing for 2 minutes under the above polishing conditions using a 1- ⁇ m thick thermal oxide film deposited on an 8-inch silicon wafer, as shown in FIG.
• the maximum polishing rate and the minimum polishing rate were determined from the film thickness measured before and after polishing at 25 specific positions, and the values were substituted into the following formula. Note that the smaller the in-plane uniformity value, the higher the wafer surface uniformity.
• In-plane uniformity (%) ⁇ (Maximum polishing rate, Minimum polishing rate) / (Maximum polishing rate + Minimum polishing rate) ⁇ X 100
• the polishing time until the polishing rate became 2000AZmin or less was accumulated.
• the laminated state of the polishing layer and the cushion layer was visually confirmed and evaluated according to the following criteria.
• a grooving machine manufactured by
• the cushion layer made of polyethylene foam (made by Torayen clay, Toraypef) adjusted to a thickness of 1.7 mm by puffing the surface is sent to the cushion layer surface while rotating the uneven roll heated to 90 ° C. By pressing, convex portions (H: 0.13 mm, W: 8 mm) were formed at regular intervals on the cushion layer surface.
• the cell-dispersed urethane composition prepared in Example 1 was continuously discharged onto the cushion layer surface. Thereafter, a laminated abrasive sheet was produced in the same manner as in Example 1.
• the polishing layer surface of the laminated polishing sheet is subjected to grooving using a grooving machine (manufactured by Toho Koki Co., Ltd.) so as to be positioned between the projections on the cushion layer surface, and the laminated polishing pad.
• H 1.3 mm, w: 2 mm, w: 12 mm.
• the cell-dispersed urethane composition prepared in Example 1 was poured into a pan-shaped open mold. When the fluidity of the composition disappeared, it was placed in an oven and post-cured at 80 ° C. for 6 hours to obtain a polyurethane resin foam block.
• the polyurethane resin foam block was sliced using a band saw type slicer (manufactured by Fetsuken) to obtain a polyurethane resin foam sheet. Then use this sheet puff machine (manufactured by AMITEC Corporation), and the surface puff to a predetermined thickness, and a sheet trimmed the thickness precision (thickness of the sheet: 1.
• the laminated polishing pad of the present invention does not peel between the polishing layer and the cushion layer and is less prone to clogging with grooves due to slurry, polishing debris and the like.

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