WO2004090963A1 - Polishing pad, process for producing the same and method of polishing therewith - Google Patents

Abstract

A polishing pad comprising fibers containing organic fibers and, retaining the fibers, a matrix resin, which at least after dressing, has at least organic fibers exposed on its surface of polishing object side. This polishing pad is capable of inhibiting the occurrence of minute polishing flaws on the polishing object and is capable of effecting flat polishing with a low load. Further, the polishing endpoint for polishing object can be controlled without any polishing flaw by means of a polishing condition detection system for polishing object utilizing an optical technique. Therefore, in, for example, the process for producing a semiconductor device, polishing with low load on interlayer insulating layers and excelling in flatness can be carried out, so that it becomes feasible to easily carry out a next-generation dual damascene process.

Description

Polishing pad, manufacturing method thereof and polishing method using the same

Technical field

 INDUSTRIAL APPLICABILITY The present invention is used for chemical mechanical polishing (CMP) in semiconductor device manufacturing technology and precision polishing in hard disk manufacturing technology.

The present invention relates to a polishing pad, a manufacturing method thereof, and a polishing method using the polishing pad.

 Background technology

 At present, ultra-large scale integrated circuits tend to increase the packaging density, and various microfabrication technologies are being researched and developed. The design rules are already in sub-half micron order. One of the technologies that have been developed to satisfy such strict requirements for miniaturization is CMP (chemical mechanical polishing) technology. This technology completely flattens the layer to be exposed in the semiconductor device manufacturing process, reduces the burden on the exposure technology, and contributes to stabilizing the production yield at a high level. It is to be implemented. The object to be polished is pressed against the polishing pad, and the polishing pad is slid relatively between the object and the polishing pad while a slurry-like CMP polishing liquid is supplied between the object and the polishing pad. In this way, a required amount of the film on the surface of the object to be polished is precisely removed. For this reason, for example, it is a technology that is indispensable when flattening an interlayer insulating film and a BPSG film, and performing isolation and wrench separation.

Foaming or non-foaming organic resin polishing pads have been used as polishing pads for these CMP technologies (Japanese Patent Application Laid-open No. Hei 8 (1996) -111210, claims). And Background of the Invention). For example, It was common to use urethane foam resin sheets with concentric or lattice grooves.

 Here, damage to the polished surface (polishing scratches) due to abrasive grains and polishing debris has become a problem. In the case of ordinary foamed or non-foamed organic resin polishing pads, lowering the hardness of the polishing pad is very effective in reducing polishing scratches. However, if the hardness is reduced, the polishing rate is reduced, and dishing in the wrench tends to worsen. It was difficult to satisfy these at the same time.

 On the other hand, the wiring process has shifted from the early A1 wiring to embedded wiring using dual damascene, which uses CU with low electrical resistance for the wiring metal and low dielectric constant material for the interlayer insulating film.

 In such a dual damascene method, selection of a polishing pad in addition to selection of a polishing liquid has become extremely important. In particular, the metal is richer in chemical reactivity and softer than the interlayer insulating film, so that it is easy to cause a polishing scratch and a defect due to a joint. On the other hand, the dishing is easy to deform, that is, the smaller the elastic modulus, the larger. However, increasing the elastic modulus of the pad generally increases the pad hardness, which causes defects such as the polishing scratches.

 In addition, the application of low dielectric constant materials to interlayer insulating films, which has been promoted in recent years, is accompanied by a decrease in mechanical properties of the insulating layer and a decrease in adhesion to metal, which causes defects during polishing. Therefore, there is a need for a polishing system that requires less mechanical load during polishing.

In addition, in these shallow wrench separation processes, the metal wiring polishing process in the dual damascene method, and the interlayer insulating film polishing process, it is necessary to control an appropriate polishing amount at the time of CMP polishing. In this method, in addition to strict control of the polishing time, torque fluctuations due to the change in the friction between the pad and the wafer during polishing of the motor that drives the polishing device are considered. There are also methods for detecting and methods for measuring the capacitance of the object to be polished. However, a polishing apparatus equipped with a sensor for optically detecting a change in the surface state of the wafer due to polishing has also been used, and a laser beam or an infrared ray is radiated from the polishing apparatus side through a polishing pad. The mainstream technology is to irradiate the polished surface of the wafer and detect the reflected light again with the sensor of the polisher via the polishing pad to control the polishing state of the wafer. In particular, the shear wrench separation process, dual damascene method, etc. expose a barrier film at the end of polishing, and a parier film is exposed on the surface. This optical technique is useful. In the process of polishing an insulating film without a noria film, the amount of polishing can be detected by interference between light reflected from the wafer surface and light reflected from the silicon layer below the insulating film. As a typical example of the polishing pad used for this optical method, a polishing pad in which a transparent window material that transmits light is inserted into a part of a foamed polyurethane resin plate is used. In addition, a technique has been proposed in which light is transmitted through a polishing pad made of a non-foamed resin such as polyurethane, polycarbonate, nylon, an acrylic polymer, or polyester (see, for example, US Pat. 60.). However, these polishing pads have problems such as optically detecting the end point, reducing polishing flaws during CMP polishing, and securing the polishing speed. In particular, in the damascene method, as described above, the polishing flaws are not suitable for polishing. It is important to reduce the occurrence of defects due to aging. Disclosure of the invention

 The present invention has been found by variously examining the structure of a polishing pad in order to solve the above problems.

The present invention provides an interlayer insulating film in a semiconductor device manufacturing process, a BPSG film, In the CMP technology used for flattening the insulating film for shear wrench separation and forming the metal wiring, etc., the flattening and efficient formation of the metal wiring are performed at the same time as scratches on the polished surface and defects in the insulating layer. It is an object of the present invention to provide a polishing pad capable of suppressing the occurrence, a manufacturing method thereof, and a polishing method using the polishing pad. In addition, light is applied to the surface of the object to be polished, such as a semiconductor wafer, through a polishing pad, and the change in the reflectance is detected, making it suitable for use in the polishing process to control the polishing end point. And a polishing pad for suppressing generation of polishing scratches on an object to be polished, and a polishing method for polishing using the polishing pad.

 The present invention provides (1) a fiber comprising an organic fiber and a matrix resin holding the fiber, and at least the organic fiber is exposed on the surface to be polished. It is related to the characteristic polishing pad.

 Further, the present invention provides (2) a fiber containing an organic fiber and a matrix resin holding the fiber, and at least the organic fiber is exposed on the surface of the object to be polished after the dressing treatment. It relates to a polishing pad characterized by this.

 The present invention relates to (3) the polishing pad according to (1) or (2), wherein the matrix resin contains at least one kind of thermoplastic resin.

 The present invention relates to (4) the polishing pad according to any one of (1) to (3), wherein the matrix resin is a semi-crystalline thermoplastic resin.

 The present invention relates to (5) the polishing pad according to any one of (1) to (4), wherein the matrix resin has an elastomer dispersed therein.

 The present invention relates to (6) the polishing pad according to (5), wherein the elastomer has a glass transition point of 0 ° C or less.

The present invention relates to (7) the polishing pad according to any one of (1) to (6), wherein the fibers are made of an aromatic polyamide. The present invention relates to (8) the polishing pad according to any one of the above (1) to (7), which contains 1 to 50% by weight of an organic fiber.

 The present invention relates to (9) the polishing pad according to any one of (1) to (8), wherein the diameter of the organic fiber is 1 mm or less.

 The present invention relates to (10) the polishing pad according to any one of (1) to (9), wherein the length of the organic fiber is 1 cm or less.

 The present invention relates to (11) the polishing pad according to any one of the above (1) to (10), wherein the polishing particles are held by organic fibers exposed on the surface to be polished.

 The present invention relates to (12) the polishing pad according to any one of (1) to (11), wherein a length of a maximum exposed portion of the exposed organic fiber is 0.1 mm or less.

 The present invention relates to (13) the polishing pad according to (12), wherein the exposed organic fibers are made of polyester.

 The present invention relates to the polishing pad according to the above (12) or (13), wherein the chopped polyester fibers are dispersed in a matrix resin (14).

 The present invention relates to (15) the polishing pad according to the above (12) or (13), wherein a polyester nonwoven fabric is laminated on a matrix resin.

The present invention provides (16) a polishing pad useful for optically detecting a polishing end point during polishing of a surface of an object to be polished, wherein the polishing pad contains organic fibers of 1 to 20% by weight. (1), which comprises a non-foamed matrix resin, has a function of transporting and holding abrasive slurry particles, and transmits light having a wavelength in the range of 190 to 35 OO nm. The present invention relates to a polishing pad according to any one of 2) to (4), (7), and (9) to (11). The present invention provides (17) an optical polishing end point during polishing of a surface of an object to be polished. W

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 A polishing pad useful for detection, including a portion through which light having a wavelength in the range of 190 to 350 nm is transmitted, wherein the portion contains 1 to 20% by weight of organic fibers. The above-mentioned (1), (2) to (4), (7), (7), which is a part 5 which is made of a substantially non-foamed matrix resin and has a function of holding and transferring abrasive slurry particles. 9) A polishing pad according to any one of (1) to (11).

 The present invention relates to (18) the polishing pad according to (16) or (17), wherein the organic fiber is an aramide fiber.

 The present invention relates to (19) a method for producing a polishing pad which is used by being attached to a surface plate to flatten a surface to be polished by L0, comprising a matrix containing fibers containing organic fibers and a thermoplastic resin. Mixing the resin composition to obtain a mixture, forming the mixture into pellets or tablets, and processing the pellets or tablets into a plate or sheet by extrusion or injection molding. The present invention relates to a method for producing an L5 polishing pad, which comprises a step of performing polishing.

 The present invention relates to (20) a method for producing a polishing pad for flattening a surface to be polished by being attached to a surface plate and comprising a matrix resin composition comprising a fiber base material containing organic fibers. A resin-impregnated sheet-like fiber base material by impregnating the same, and a step of laminating the sheet-like fiber base material containing the resin-impregnated sheet-like fiber base material: 0, and applying heat and pressure molding. The present invention relates to a method for producing a polishing pad characterized by the above.

 The present invention relates to (21) the method for producing a polishing pad according to the above (19) or (20), further comprising a step of exposing the fibers to the surface.

The present invention provides (22) a polishing surface of an object to be polished is pressed against an organic fiber exposed surface of the polishing pad according to any one of the above (1) to (18) 5, and a polishing liquid is polished with the polishing surface. The present invention relates to a polishing method for polishing a surface to be polished by relatively sliding an object to be polished and a pad while supplying the space between the object and the pad. The present invention provides (23) the above-mentioned (22), wherein the polished surface comprises a laminate in which a conductor layer and a copper layer are further coated on an insulating layer having a dielectric constant of 2.7 or less, on which wirings and trenches are formed. The present invention relates to the polishing method described above.

 The present invention relates to (24) a polishing method for optically detecting a polishing end point using the polishing pad according to any one of (16) to (18).

 The organic fibers exposed on the surface alleviate the stress between the polishing object and the abrasive grains in the polishing liquid during polishing and prevent the surface of the object from being damaged. Also, in the conventional polishing pad consisting of only a general resin, the foaming holes and the large and small grooves on the surface serve to transport and retain the abrasive grains of the polishing liquid. The organic fibers exposed to the surface have the ability to transport and hold the abrasive grains of the polishing liquid, and play a role in obtaining the polishing rate and improving the flatness uniformity. BEST MODE FOR CARRYING OUT THE INVENTION

 The structure of the polishing pad of the present invention comprises fibers containing organic fibers and a matrix resin holding the fibers. The organic fibers may be part or all of the fibers, and the fibers may include inorganic fibers such as glass fibers in addition to the main organic fibers.

 There is no particular limitation as long as at least organic fibers are exposed on the surface to be polished. In the present invention, the expression that the organic fiber is exposed includes the surface to be polished after the dressing treatment, that is, at least the organic fiber is exposed at the time of use.

 The specific structure of the polishing pad is a structure in which fiber in the shape of a chip is dispersed in a matrix resin, and a structure in which nonwoven fabric or woven fibers are laminated in the matrix resin. And the like.

As a matrix resin for holding the fibers of the polishing pad of the present invention As for, ordinary thermosetting resins and thermoplastic resins can be used without any particular limitation. Preferably, it is a resin belonging to the class of relatively high elastic modulus, for example, a resin having a room temperature elastic modulus of the cured product of at least 0.1 GPa, more preferably at least 0.5 GPa. If the elastic modulus is small, the flatness tends to deteriorate.

 As the thermosetting resin, for example, bisphenol A type epoxy resin, epoxy resin such as cresol novolak type epoxy resin, unsaturated polyester resin, acrylic resin, polyurethane resin and the like can be used. These may be used alone or in combination of two or more. When these thermosetting resins are epoxy resins, a curing agent, a curing accelerator and the like are usually added. As a curing agent, dicyan diamide, an organic acid, an organic acid anhydride, a polyamine and the like can be used. As a curing accelerator, for example, 2-ethyl-4-methylimidazole and the like can be used.

 Examples of the thermoplastic resin include polycarbonate, polymethyl methacrylate, AS (acrylonitrile-styrene copolymer), and ABS (acrylonitrile-butadiene rubber-styrene copolymer). , Polyethylene, polypropylene, polybutene, 4-methyl-pentene-1, ethylene-propylene copolymer, ethylene-vinyl acetate copolymer, polyester, polyamide, polyamide imide, polyacetone, etc. Is mentioned. These may be used alone or in combination of two or more. In particular, if a semi-crystalline thermoplastic polymer resin is used as the matrix resin, a polishing pad having excellent wear resistance and high durability can be obtained.

A first embodiment of the polishing pad of the present invention is a polishing pad in which the matrix resin contains at least one kind of thermoplastic resin. Here, the matrix resin includes at least one kind of thermoplastic resin. If it can be used, there is no particular limitation, and it is preferable that the thermoplastic resin is the main component.

 A second embodiment of the polishing pad of the present invention is a polishing pad in which the maximum length of the exposed portion of the organic fiber exposed on the surface to be polished is 0.1 mm or less. Here, the maximum exposed portion length of the exposed organic fiber is substantially the length of the exposed portion of the fiber fixed to the surface of the polishing pad, and means the largest one. In practice, measurement can be made by observing about 5 or more points on the pad surface using a scanning electron microscope (SEM) or the like.

 A third embodiment of the polishing pad of the present invention is a polishing pad useful for optically detecting the polishing end point during polishing of the surface of the object to be polished. It is made of a substantially non-foamed matrix resin containing 1 to 20% by weight of organic fiber that transmits light having a wavelength in the range of 90 to 350 nm and transports and transfers abrasive slurry particles. This is a polishing pad that has a retaining function.

Regarding the matrix resin, particularly in the first embodiment, in addition to the above-mentioned thermoplastic resin, additives such as cross-linked and uncross-linked elastomers, cross-linked polystyrene, cross-linked polymethyl methacrylate, and the like are further added. May be mixed and dispersed in a matrix resin. It is more preferred to add a thermoplastic elastomer and a low cross-linking elastomer. The elastomer can be used without any particular limitation as long as it has a glass transition point of room temperature or lower, and more preferably 0 ° C or lower. For example, an elastomer such as an olefin-based elastomer, a styrene-based elastomer, a urethane-based elastomer, an ester-based elastomer, an alkenyl aromatic compound-conjugated-gen copolymer, a polyolefin-based copolymer, and the like. Is mentioned. The greater the amount of these elastomers added, the higher the impact resistance It becomes a high and tenacious resin, and the frictional force between the pad surface and the metal increases.

 As the organic fibers in the polishing pad of the present invention, fibrous materials such as aramid, polyester and polyimide can be widely used. Also, two or more of these can be selected and mixed for use.

 From the viewpoints of pad durability and retention of abrasive particles by the fibers, it is preferable to select aramid, that is, an aromatic polyamide fiber alone or as a main component, and it is preferable to use aramid fibers alone. More preferred. That is, the aramide fiber has a higher tensile strength than other general organic fibers, and when the polishing pad surface of the present invention is mechanically roughened to expose the fibers, the fibers are likely to remain on the surface. Therefore, it is effective for retaining the abrasive particles. It also has the effect of improving the durability of the polishing pad and extending the service life. Alamide fibers are particularly preferred in the case of the first and third embodiments.

 There are para-type and meta-type of aramide fiber, but para-type aramide fiber is more preferable because it has higher mechanical strength and lower hygroscopicity than meta-type fiber. As the para-based aramide fiber, poly-P-phenylene terephthalamide fiber and poly-P-phenylene phenyl ether terephthalamide fiber are commercially available and can be used.

Further, from the viewpoint of the maximum exposure length and the adjustment of the surface roughness, it is preferable that the organic fiber is mainly composed of polyester. This is because, when the fibers of the polishing pad are exposed, the maximum exposed length can be reduced because the shear strength of the polyester fibers is smaller than that of the hard fibers. It is particularly preferable in the case of the polishing pad of the second embodiment. On the other hand, when other hard fibers such as aramide fibers and polyimide fibers are used, the maximum exposed length is adjusted by reducing the particle size of the grindstone used. At this time, since the pad surface roughness depends on the above-mentioned grain size, Inevitably, the unevenness of the surface of the pad itself is affected, which affects the polishing rate. On the other hand, when polyester is used, the exposed length hardly changes even if a grindstone of any particle size is used. Therefore, the surface roughness of the pad itself can be adjusted arbitrarily while keeping the fiber length constant.

 Here, the above-mentioned hard fiber may be mixed with the polyester fiber and used. At this time, the ratio of the polyester fiber is preferably from 40 to 100% by weight, more preferably from 70 to 100% by weight, and further preferably from 80 to 100% by weight. When the amount of polyester fiber is large, the exposed fiber layer becomes small, and when the amount of hard fiber is large, the thickness becomes thick and the flatness tends to be deteriorated.

 The fiber diameter (diameter) of the organic fiber is preferably 1 mm or less, and is preferably 200 ^ m or less. Preferably it is 1 to 200 zm, more preferably 5 to 150 / zm. If it is too thick, the mechanical strength will be too high, which may cause polishing scratches and poor dress. If it is too thin, the handleability may decrease, or the durability of the pad may decrease due to insufficient strength.

 The fiber length is not particularly limited, but is preferably 10 mm or less, and more preferably 5 mm or less in the case of a polishing pad in which fibers are dispersed in a chopped shape in a resin. . More preferably, it is 0.1 to 3 mm. If it is too short, the exposed fibers will not be effectively retained by the pad when the pad surface is mechanically roughened, and if it is too long, it will thicken when mixed with the resin, making molding difficult. There are cases. These can be used in the form of chopped short fibers cut to a predetermined length, or in the form of a mixture of several fiber lengths.

Further, in order to improve the affinity with the resin, the fiber surface may be mechanically or chemically roughened in advance, or may be modified by a coupling material or the like. For handling reasons, use short fiber chops with a very small amount of resin. Can be used as a bundle. However, it is only necessary that the short fibers have such a holding force that the short fibers are dispersed in the matrix resin by heating during mixing with the matrix resin or by an applied shearing force.

 In the case of a polishing pad in which a nonwoven fabric or a woven fabric is laminated, when using a nonwoven fabric, the same fibers having a length of 1 mm or more as described above are fused together using a fusion bonding agent of the fibers themselves or an adhesive. Those molded into a single piece can be used. As the adhesive, an adhesive made of an epoxy resin such as a water-soluble epoxy resin binder can be used. When an adhesive is used, its amount is not particularly limited, but is preferably 3 to 20 parts by weight, more preferably 5 to 15 parts by weight, per 100 parts by weight of the fiber. . In the case of a woven fabric in which long fibers are made into a woven form, the weaving method can be used without any particular limitation. The polishing pad on which such fibers are laminated is particularly suitable for the polishing pad of the second embodiment of the present invention.

The unit weight of the above nonwoven fabric and woven fabric is preferably 36 to 100 g / m ^2, and more preferably 55 to 72 g Zm ² .

 The content of the organic fibers is not particularly limited, but when chop fibers are used for the entire pad, it is preferably 1 to 50% by weight of the whole pad, more preferably 1 to 2% by weight. 0% by weight, more preferably 5 to 20% by weight. When the amount of fiber is small, there is a tendency that the polishing scratches on the polished surface become remarkable, and when the amount is too large, the moldability deteriorates. On the other hand, in the case of a woven or nonwoven fabric, the content is preferably 50% by weight or more, and more preferably 60 to 80% by weight.

In particular, in the case of the third embodiment, the content of the organic fiber in the light-transmitting portion needs to be in a range where the light-transmitting property is not impaired and the polishing state of the wafer can be detected. Therefore, 1 to 20 times the entire polishing pad %, More preferably 2 to 10% by weight. When the amount of fiber is small, the polishing scratches on the polished surface become remarkable, and when the amount is too large, the moldability tends to deteriorate.

 The above-mentioned polishing pad is a method of dispersing and molding fibers in a resin composition to be a matrix, and impregnating a resin varnish into a woven or non-woven fabric containing fibers to obtain a pre-preda and laminating. Etc., but is not limited thereto.

 Hereinafter, a method for producing the polishing pad of the present invention will be described.

 The first production method includes a step of mixing a fiber containing an organic fiber and a matrix resin composition to obtain a mixture, a step of forming the mixture into a pellet or a sunset, and a step of mixing the pellet or tablet. Extruding into a plate or sheet by extrusion molding or injection molding. The second production method comprises a step of impregnating a matrix containing an organic fiber with a matrix resin composition to produce a resin-impregnated sheet-like fiber base; Including the step of laminating the sheet-like fiber base materials and applying heat and pressure. It is preferable that the fiber base material mainly contains polyester fiber.

 The method of preparing the matrix resin composition for producing the polishing pad of the present invention and the method of mixing with the fiber can be performed by a conventionally known method, and is not particularly limited.

That is, when the chopped fibers are directly dispersed in the matrix resin composition as the first production method, for example, each resin composition forming the matrix may be mixed with a Henschel mixer, a super mixer, After uniformly mixing (drive blending) with a mixer, repump blender, etc., melt-knead with a single-screw extruder, twin-screw extruder, Pampari mixer, etc. Further, fibers are added and melt-mixed in the same manner. After that, it is cooled and made into an evening bullet or pellet. Use water for cooling If it does, it must be sufficiently dried and dehydrated.

 The obtained tablet or pellet is again extruded through a die by an extruder and rolled with a roll to produce a sheet or plate-like molded product. Further, as another manufacturing method, a sheet-shaped or plate-shaped molded article may be formed by injection molding into a mold instead of the extrusion molding.

 On the other hand, when the matrix resin composition is a liquid thermosetting resin composition, a predetermined amount of the chip-like fibers is dispersed in the liquid thermosetting resin composition, poured into a mold or the like, and depressurized. After removing the air bubbles, the molded product can be obtained by heating and curing. Similarly to the above, it may be manufactured by pressurizing and pouring a mold in a heated state.

 The second manufacturing method can also be performed by a conventionally known method, and is particularly suitable for manufacturing the polishing pad of the second embodiment. For example, when a woven or non-woven fabric is used as the fiber base material, the above-mentioned resin L5 resin-impregnated sheet fiber base material, resin-impregnated sheet fiber base material, and resin-unimpregnated sheet fiber base material are used. (Ie woven or non-woven). These can be integrated by heat and pressure molding to obtain a molded product. At this time, it is preferable to arrange the resin-unimpregnated sheet-like fiber base material on at least one surface, so that the state where the organic fibers are exposed on the surface is zero.

The resin-impregnated sheet fiber base material is obtained by impregnating a resin composition into a resin-unimpregnated sheet fiber base material, and is usually called a pre-preda. The preparation method of the prepreg is not particularly limited.However, a varnish prepared by dissolving the matrix resin composition component in an organic solvent is prepared, and after impregnating the resin-unimpregnated sheet fiber base material, It can be obtained by heating and drying. The type of solvent can be used without any particular limitation as long as it can dissolve the resin composition uniformly. For example, methyl ethyl ketone, Examples include ketones such as methyl isopropyl ketone and acetone, lower alcohols such as ethyl alcohol, propyl alcohol and isopropyl alcohol, and amides such as dimethyl formamide and formamide. It is also possible to use a mixture. The content of the fibers in the resin-impregnated sheet-like fiber base material is desirably 60 to 140 parts by weight based on the total of 100 parts by weight of the resin composition and the adhesive. And more preferably 90 to 120 parts by weight.

 The ratio of the sheet fiber base material not impregnated with resin to the whole is determined in consideration of the fiber content in the polishing pad, particularly the organic fiber content of the surface layer which is pressed against the object to be polished. decide. According to this method, in order to change the fiber content of the polishing pad, it is not necessary to change the resin content at the time of manufacturing the above-mentioned pre-prepader, and it is possible to change the usage ratio of the resin-impregnated sheet fiber base material. Can be adjusted.

 In the heat and pressure molding, generally, the heating temperature is usually from 150 to 200, and the pressure is from 50 to 500 kPa. These can be appropriately adjusted depending on the type and content of the thermosetting resin to be used.

 These molded products are appropriately processed according to the shape of a platen of a predetermined polishing device as required, and a polishing pad of a final product is obtained. As an example, a polishing pad as a final product can be obtained by cutting the above sheet-like molded product into a circular shape.

 The overall thickness of the polishing pad is preferably from 0.1 to 5 mm, more preferably from 0.5 to 2 mm. Further, a groove to be a flow path of the polishing liquid and the polishing debris may be formed on the polishing surface of the pad in a concentric shape or a lattice shape using an NC lathe or the like.

In order to obtain a polishing pad according to the present invention in which at least the organic fibers are exposed on the surface to be polished, the surface of the pad to be polished is exposed, if necessary, to expose the fibers. The method of forming the exposed fiber is as follows. It is possible to adopt a method in which the resin is removed from the pad surface using a grinding stone such as a diamond or the like to expose the fibers. Instead of a grindstone, a wire brush, a metal screwdriver, a resin brush, glass or a ceramic plate may be used.

 These conditions must be well adjusted to control the exposed length of the fiber. The maximum exposed fiber length greatly depends on the hardness of the fiber, but if polyester fiber is used for the pad, the length can be easily adjusted.

 In general, the maximum length of the portion exposed on the surface of the organic fiber can be practically used in a range of 1 mm or less, and is preferably 200 zm or less. More preferably :! 200200 m, more preferably 10 1150 mm. If the length is too short, the retention of the polishing liquid will decrease, and the polishing rate will decrease. If the length is too long, the flatness tends to be adversely affected.

 In particular, in the polishing pad according to the second embodiment of the present invention, the length of the exposed portion of the organic fiber is not more than 0.1 mm. Here, the maximum length of the exposed portion can be used without particular limitation as long as it is 0.1 mm or less, preferably 1 to 50 tm, more preferably; ~ 25 im. As the maximum exposed portion length increases, the flatness tends to decrease, and as the maximum exposed portion length decreases, the polishing rate tends to decrease.

 By the organic fibers exposed on the surface to be polished, polishing particles (abrasive particles) in a polishing liquid, which will be described later, can be efficiently held during polishing.

Next, a polishing pad according to a third embodiment of the present invention will be described. This polishing pad optically detects the polishing amount of the object to be polished, manages its end point, and suppresses the occurrence of polishing scratches during polishing while maintaining a high polishing rate and uniformity. is there. Such a configuration can be realized by devising the structure of the polishing pad, the resin composition, the filling, and the like. The structure of the polishing pad is such that the material of the polishing pad is transparent to light having a wavelength in the range of 190 to 350 nm, or part of the polishing pad. It is formed of a material having this light transmitting property. In the latter, for example, a member of this polishing pad is formed into a small piece, and is introduced as a window material for transmitting light to a part of the polishing pad that does not have sufficient light transmittance. is there.

 Thus, since the polishing pad or a part thereof transmits light having a wavelength in the range of 190 to 350 nm, light is transmitted through the polishing pad to the polished surface of the object to be polished. By irradiating and detecting a change in the reflectance, the polishing end point can be controlled. In the present invention, transmitting a light beam having a wavelength in the range of 190 to 350 nm generally means the transmittance of a polishing pad or a part thereof having a wavelength of this wavelength before exposing the organic fiber. Means 100% to 100%. This transmittance is preferably between 30 and 100%.

 As a matrix resin used for such a material having light transmittance, a resin belonging to a class having a relatively high elastic modulus is preferable, and each of the above-mentioned resins can be used without particular notice. In particular, if a semi-crystalline thermoplastic high molecular resin is used, a polishing pad having excellent abrasion resistance and high durability can be obtained. The resin is preferably in a form having substantially no foamed pores. This is because the form having the foam holes impedes light transmission and impairs detection of the polishing state of the wafer. As the organic fiber, it is preferable to select an aramide fiber alone or as a main component.

The manufacturing method is the same as the above-described manufacturing method.Each molded product is cut into a circular shape or the like according to the shape of the surface plate of a predetermined polishing machine to form a polishing pad, or the molded product is cut into small pieces. Processed and cut off part. Insert the other low-light-transmitting polishing pad as a light-transmitting window into a polishing pad that can detect light. In the latter case, the effect of the present invention In order to increase the height, it is desirable that the polishing pad with low light transmittance, through which the windows are inserted, is also formed of a resin plate or the like containing organic fibers. There are no restrictions. In addition, the introduced window material must be in contact with the object to be polished on the pad surface during polishing. This is because if there is a large gap between the window material and the object to be polished, the polishing liquid flows in, scatters the transmitted light, and inhibits light detection. The shape of the window is not particularly limited, but its size must be large enough to secure the optical path necessary for the operation of the system consisting of the light irradiation and detection sensor attached to the polishing device that performs light detection. Preferably, the area is about 0.1 to 10% of the entire polishing pad surface.

 Hereinafter, a polishing method using the polishing pad of the present invention will be described. In the polishing method of the present invention, the surface to be polished of the object to be polished is pressed against the exposed surface of the organic fiber of any of the above-mentioned polishing pads of the present invention, and a polishing liquid is applied between the surface to be polished and the polishing pad. This is a polishing method for polishing the surface to be polished by relatively moving the object and the pad while supplying them.

 In the shallow-to-wrench separation process, a device pattern to be formed with a silicon nitride film is formed as the object to be polished, and then the exposed Si portion is etched, and a silicon oxide film is formed thereon by TEOS-plasma CVD. In the damascene method, the formed substrate is provided with a via conductor and a wiring trench formed on the interlayer insulating film formed by dry etching, a barrier conductor film covering the opening and the inner wall completely, and a CU film thereon. Substrates in which the openings are completely buried and grown are mentioned.

The CMP polishing liquid used in the polishing method of the present invention is not particularly limited. For example, for an insulating film, a composition comprising cerium oxide particles (ceria) or silicon oxide (silica) and a dispersant is mixed with water or the like. Dispersed in a dispersing medium of the above, and further obtained by adding an additive. Polishing liquids for metal layers such as CU include silica, alumina, cerium, titania, A polishing liquid in which abrasive grains such as zirconia and germania, additives and an anticorrosive are dispersed in water, and a peroxide is further added. As the abrasive, colloidal silica particles or alumina particles are particularly preferable. The content of the abrasive particles is preferably 0.1 to 20% by weight. The production method of the abrasive particles is not limited, but the average particle size is preferably from 0.01 to 1.0 ^ m. If the average particle size is less than 0.01 m, the polishing rate is too low, and if the average particle size is more than 1.0 ^ m, it is easy to be damaged.

 There is no particular limitation on the polishing apparatus, and it can be used in a disk-type polishing apparatus and a linear-type polishing apparatus. For example, a general polishing apparatus having a holder for holding an object to be polished and a polishing platen to which a polishing pad is attached and a motor or the like capable of changing the rotation speed is attached can be used. . As an example, a polishing machine manufactured by EBARA CORPORATION: model number EP0111 can be used. In particular, in the polishing method using the polishing pad of the third embodiment for optically detecting the polishing end point, the polishing pad is used to relatively slide the object to be polished and the polishing pad as described above. While polishing the surface to be polished, a light beam having a wavelength of 190 to 350 O nm is applied to the polished surface of the object to be polished through a polishing pad to detect a change in the reflectance. Thus, the polishing end point is managed.

When the polishing pad of the third embodiment is used, the polishing device is a laser beam irradiation and reflected light on a surface plate on which the polishing pad is attached, such as a MIRRA polishing device manufactured by Applied Materials of the United States. It is necessary to have a device for detecting There are no particular restrictions on the polishing conditions, but it is desirable to optimize the polishing conditions. In order to polish accurately, the silicon nitride film is exposed in the shallow wrench separation process, and in the damascene method, the exposure of the barrier film is detected and the reflection of the light irradiating the wafer surface is detected. Manage endpoints. At this time, a program for controlling the progress of polishing is incorporated in the polishing apparatus in advance. In order to fix the polishing pad of the present invention to the surface plate of the polishing apparatus, an adhesive such as a double-sided adhesive tape can be used on the side opposite to the polishing surface. Further, it may be attached via a low elasticity subpad made of foamed polyurethane or the like.

 In order to grind the polishing pad by sliding the polishing pad and the object to be polished while the surface to be polished is pressed against the polishing pad, concretely, the object to be polished and the polishing platen are At least one of them should be moved. In addition to rotating the polishing platen, the polishing may be performed by rotating or swinging the holder. In addition, a polishing method in which a polishing platen is rotated in a planetary manner, a polishing method in which a belt-shaped polishing pad is linearly moved in one direction in a longitudinal direction, and the like are included. The holder may be fixed, rotated, or rocked. These polishing methods can be appropriately selected depending on the surface to be polished and the polishing apparatus as long as the polishing pad and the object to be polished are relatively moved.

 The polishing conditions are not particularly limited, but it is desirable to optimize them according to the object to be polished. For example, the rotation speed of the polishing platen is preferably 200 rpm or less so that the object to be polished does not pop out, and the pressure applied to the object to be polished is a pressure at which no scratch occurs after polishing, for example, the surface to be polished is In the case of copper, it is preferably about 50 kPa or less. Further, when a polishing object having a low dielectric constant interlayer insulating film is used, it is preferably 20 kPa or less.

 During polishing, a polishing liquid is continuously supplied between the polishing pad and the surface to be polished by a pump or the like. The supply amount is not limited, but it is preferable that the surface of the polishing pad is always covered with the polishing liquid. The wear of the pad and the exposed organic fibers due to polishing is regenerated and maintained by dressing. It is desirable that the object to be polished after the polishing is thoroughly washed with running water, and that water drops adhering to the polished surface be removed using a spin dryer or the like, and then dried.

Hereinafter, as one embodiment of the polishing method of the present invention, wiring of a semiconductor device A description will be given of a polishing method in which the surface to be polished is formed by laminating a dielectric conductor layer and a metal layer such as copper on an insulating layer on which a wiring or a trench is formed.

 The metal layer is mainly composed of a group consisting of copper, copper alloy, copper oxide, copper alloy oxide (hereinafter referred to as copper and its compounds), tungsten, tungsten alloy, silver, gold and the like. It is preferable that copper such as copper and its compound be a main component.

 As the barrier conductor layer (hereinafter, referred to as a barrier layer) coated on the metal layer, of the above metals, the barrier layer for the above copper and its compounds, particularly copper and copper alloy is used. preferable. The barrier layer is formed to prevent diffusion of the metal layer into the insulating film and to improve the adhesion between the insulating film and the metal layer. Examples of the composition of the conductor include tantalum, titanium, tungsten, and compounds such as nitrides, oxides, and alloys thereof.

 Examples of the insulating film include a silicon-based film and an interlayer insulating film of an organic polymer film. Examples of the silicon-based coating include silica-based coatings such as silicon dioxide, fluorosilicate glass, organosilicate glass obtained from trimethylsilane dimethydimethyldimethylsilane as a starting material, silicon oxide nitride, and hydrogenated silsesquioxane. And silicon carpide and silicon nitride. The organic polymer film includes a wholly aromatic low dielectric constant interlayer insulating film. In particular, the interlayer insulating film preferably has a dielectric constant of 2.7 or less.

First, an interlayer insulating film such as silicon dioxide is laminated on a silicon substrate. Next, a concave portion (substrate exposed portion) of a predetermined pattern is formed on the surface of the interlayer insulating film by a known means such as formation of a resist layer and etching to form an interlayer insulating film having a convex portion and a concave portion. On this interlayer insulating film, a barrier layer such as tantalum, which covers the interlayer insulating film, is formed along the surface irregularities by vapor deposition or CVD. In addition, the recess will be filled. A metal layer, such as copper, covering the barrier layer is formed by vapor deposition, plating, CVD, or the like.

 Next, the metal layer on the surface of the substrate is polished by CMP using the polishing pad of the present invention while supplying a polishing liquid (first polishing step). As a result, a desired wiring pattern in which the barrier layer of the convex portion on the substrate is exposed on the surface and the metal film is left in the concave portion is obtained. When the polishing proceeds, a part of the barrier layer of the convex portion may be polished simultaneously with the metal layer. In the second polishing step, at least the exposed barrier layer and the recessed metal layer are removed by CMP using a polishing liquid capable of polishing the metal layer, the barrier layer and the interlayer insulating film. Grind. A desired pattern is obtained in which the interlayer insulating film under the convex barrier layer is entirely exposed, the metal layer serving as a wiring layer remains in the concave portion, and the cross section of the barrier layer is exposed at the boundary between the convex portion and the concave portion. The polishing is terminated at the time when the polishing is performed. The polishing pad of the present invention is used at least in the second polishing step, and is preferably used also in the first polishing step as in this embodiment.

 In order to ensure better flatness at the end of polishing, further polishing is performed (for example, when the time required to obtain a desired pattern in the second polishing step is 100 seconds). Further, polishing for an additional 50 seconds is referred to as 50% polishing.) The polishing may be performed to a depth including a part of the interlayer insulating film in the convex portion.

The polishing pad of the present invention and the polishing method using the same include not only a film mainly containing a metal such as Cu, Ta, TaN or A1 which is embedded in the composite opening of the insulating layer described above, but also Silicon oxide film formed on a predetermined wiring board Glass, inorganic insulating film such as silicon nitride, film mainly containing polysilicon, optical glass such as photomask, lens, prism, etc., inorganic conductive film such as ITO, glass Integrated circuit composed of crystalline and crystalline materials '' Optical switching element · Optical waveguide · End face of optical fiber, Single crystal for optical, solid-state laser single crystal, sapphire substrate for blue laser LED, semiconductor single crystal such as SiC, Gap, GaAs, glass or aluminum substrate for magnetic disk, magnetism It can also be applied to polishing of heads and the like. Example

 Hereinafter, the present invention will be described with reference to examples, but the present invention is not limited to these examples.

(Example 1)

 Poly-P-phenylene terephthalamide fiber as organic fiber (Kepler, trade name, manufactured by Dupont, fiber diameter 12.5 zm, fiber length 3 mm), ABS resin pellet as matrix composition Was melted and mixed by an extrusion molding machine and made into a bullet. Here, the poly-p-phenylene terephthalamide fiber is extruded after drying a tablet adjusted to 10% by weight at 120 ° C for 5 hours in a large dryer. A sheet-like molded product with a thickness of 1.2 mm and a width of lm was produced using the molding and rolls. Grooves having a rectangular cross section of 0.6 mm in depth and 2. O mm in width were formed in a grid pattern with a pitch of 15 mm, and then cut out in a circle. In addition, a double-sided tape was bonded to the opposite side of the grooved surface to form a polishing pad.

(Example 2)

 A polishing pad was obtained in the same manner as in Example 1 except that polyethylene, polypropylene, and styrene-based elastomer were mixed in a weight ratio of 50: 50: 100 as a matrix composition.

(Example 3)

A polishing pad was obtained in the same manner as in Example 1, except that polypropylene was used as the matrix composition. (Comparative Example 1)

 A polishing pad was prepared in the same manner as in Example 1 except that no organic fiber was used.

(Comparative Example 2)

 A polishing pad made of foamed polyurethane was prepared.

 Each of the above pads was attached to the surface plate of a polishing machine, and the surface was roughened for 30 minutes with a dresser equipped with a # 160-count diamond grindstone (preparation of polishing liquid)

 Abrasive-free abrasive (HSC430 slurry, manufactured by Hitachi Chemical Co., Ltd.) as a polishing liquid for copper and colloidal silica with an average secondary particle diameter of 35 nm added to this to adjust to 0.37% by weight The abrasive containing the abrasive grains was used. At the time of use, both were mixed in a polishing solution: hydrogen peroxide solution = 7: 3 by volume ratio.

 (Substrate polishing)

 Using the polishing pads prepared in Examples and Comparative Examples and the above-mentioned polishing liquid, a silicon wafer substrate having no wiring or having wiring formed was polished as follows, and the polishing rate, polishing scratches, and flatness indicators were as follows. The dishing was measured as.

That is, the wafer was set on a holder to which a suction pad for attaching a wafer of a polishing apparatus was attached. Further, the polishing pads prepared in Examples and Comparative Examples were attached to the polishing platen of the polishing apparatus, and the holder was mounted on the polishing apparatus with the surface to be polished facing down. While supplying the polishing liquid at 150 cc / min, the platen and the wafer were rotated at 38 rpm, and polished at a processing load of 4 × 10 ⁴ Pa, and evaluated. Table 1 shows the results. (Evaluation of polishing rate)

Polishing for 2 minutes using a silicon wafer substrate (diameter: 13 cm) with a silicon dioxide film layer without wiring formed by forming a copper film with a thickness of 1 _t m went. The copper film thickness before and after polishing was measured for sheet resistance using a model number RT-7 manufactured by Nabson Corporation, and the film thickness was calculated from the resistivity.

The difference in film thickness before and after P was calculated. The results are shown in Table 1.

 (Evaluation of polishing scratches)

 Table 1 shows the results of the visual evaluation of the scratches using the wafer whose polishing rate was evaluated.

：: Less than 5 scratches on the polished surface after polishing

X: 5 mm or more scratches on the polished surface after polishing

 (Dishing amount)

 A silicon dioxide film with a thickness of 300 nm is formed on a silicon wafer, a trench with a wiring density of 50% and a depth of 0. is formed in the silicon dioxide, and a barrier layer is formed by a known sputtering method. A 50-nm-thick tantalum nitride film was formed as above, and a copper film was similarly formed to a thickness of 1.0 Om by a sputtering method and buried by a known heat treatment. Wiring metal part (copper) width 100 A silicon substrate (13 cm in diameter) having a surface shape of a strip-shaped pattern portion in which m and insulating film (silicon dioxide) portions having a width of 100 m were alternately arranged was prepared.

 Using the object to be polished, two-stage polishing consisting of polishing of a copper film and polishing of a parier layer is performed. From the surface shape of the tripe pattern portion, the amount of film reduction of the wiring metal portion relative to the insulating film portion was measured. The results are also shown in Table 1. In addition, "measurement impossible" in the table indicates a state where the substrate cannot be polished at a low polishing rate or the number of polishing scratches is too large to measure.

The polishing pads produced in Example 1 and Comparative Example 1 had the same matrix resin, and differed in whether or not they contained fibers. Example 1 which is the polishing pad of the present invention is excellent in that generation of scratches is suppressed as compared with Comparative Example 1 which does not contain organic fibers. Comparative Example 1 had severe polishing scratches and dates. Thing measurement was not possible. In the examples, it is apparent that the polishing is hardly performed when the abrasive free abrasive is used, and that the polishing is performed by a polishing apparatus different from Comparative Example 1 or Comparative Example 2 having a high polishing rate.

 table 1

Subsequently, the polishing liquid using abrasive containing polishing agent showing high stock removal rate from consideration of the above and the results except for using the processing load 2 xi 0 ⁴ P a was evaluated polished as above Table 2 Show. 'Here, from Table 2, it was confirmed that in the example, there was almost no difference in the polishing rate from the above polishing conditions, and polishing was possible even with a low load, that is, a low frictional force. On the other hand, in the comparative example, the polishing rate was extremely reduced under a low load under these conditions.

 Table 2

以上の検討から、 本発明による研磨パッ ドを使用すれば、 C M P 時に絶縁層にかかる負荷を低減しつつ、 平坦性を向上できる こ とが 分かった。

From the above studies, it was found that the use of the polishing pad according to the present invention can improve the flatness while reducing the load on the insulating layer during CMP.

Next, according to the embodiment, the light is applied to the surface of the semiconductor wafer through the polishing pad. The polishing pad of the present invention suitable for use in a polishing process for irradiating a laser beam, detecting a change in the reflectance thereof, and managing a polishing end point will be described, but the present invention is limited to these examples. Not something.

 The following plate materials 1 to 3 were prepared for preparing the polishing pad.

 [Sheet 1]

 Poly-P-phenylene terephthalamide fiber (Dubbon “Kepler”, fiber diameter 12.5 m, fiber length 3 mm) as organic fiber, AS resin pellet as matrix resin (Nippon Aian Doel) Made by Co., Ltd., trade name: Lightac A-100 PC) was melt-mixed with an extruder and made into an evening tablet. Here, the poly-p-phenylene phthalamide fiber was adjusted to 5% by weight. After drying the tablets at 120 ° C for 5 hours using a large dryer, a sheet-like molded product having a thickness of 1.2 mm and a width of lm was produced by extrusion and rolls.

 [Plate 2]

 The AS resin pellet (same as above) was melted with an extruder and formed into tablets. After drying this evening bill at 120 ° C for 5 h using a large dryer, a sheet-like molded product with a thickness of 1.2 mm and a width of 1 m was produced by extrusion and rolls. This board does not contain organic fibers.

 [Plate 3]

Para-aramid fiber chop (fiber diameter: 12.5 m, fiber length: 5 mm, DuPont "Kepler") and para-aramid fiber fiber pulp (fibre diameter: 1 m, fiber length: 1 mm) , DuPont “Kepler”) and meta-based aramid fiber chops (fiber diameter: 25 Atm, fiber length: 6 mm, softening temperature: 280, Teijin Limited “Cornex”) Then, a 20% by weight aqueous solution of a water-soluble epoxy resin binder (glass transition temperature: 110 ° C, manufactured by Dainippon Ink and Chemicals, Inc., trade name: “V-coat”) was used. Play, heat dry (150 ° C, 3 min), and pass between a pair of heat rolls (temperature: 300 ° C, line pressure: 196 kN / m). A non-woven fabric was prepared by heat-compressing and heat-sealing the meta-based aramide fiber chop to the para-based aramide fiber chop. Unit mass 70 g Zm ² , para-based aramide fiber chop Z para-based aramide fiber pulp Z meta-based aramide fiber chip Z Epoxy resin binder compounding mass ratio 58/17/8/1 It was 7.

 Bisphenol A type epoxy resin blended with dicyandiamide as a curing agent and 2-ethyl-14-methylimidazole as a curing accelerator (trade name “EP-828SK”, manufactured by Yuka Shell Co., Ltd.) Got ready. For the preparation of the varnish, 100 parts by weight of bisphenol A-type epoxy resin, 20 parts by weight of a curing agent, 0.1 part by weight of a curing accelerator, and 40 parts by weight of methylethyl ketone as a solvent were used. .

 The varnish was impregnated into the above-mentioned aramide fiber nonwoven fabric and dried by heating (170 ° C, 5 min) to obtain a prepreg. In this pre-preparer, the amount of resin adhered was adjusted so that the thickness after heating and pressing was 0.08 mm. The content of the aramide fiber nonwoven fabric is 60% by weight.

 A release film (polypropylene film with a thickness of 5 Ozm) was placed on both surfaces of a pre-prelayer layer consisting of one or two sheets of this pre-predeer, sandwiched between stainless steel mirror plates, and a plurality of sets of press plates were pressed. Into a hot platen and heat and pressure molded with a cushion material of 10 mm thick consisting of a craft paper layer (temperature: 170 ° C, pressure: 300 ° C). A laminate having a thickness of 1.0 mm was obtained at kPa, time of 120 min).

 (Example 3)

The plate 1 is processed into a disk shape with a diameter of 500 mm using the plate material 1, and the polishing liquid supplied during polishing passes under the jig holding the wafer and flows under the wafer. Processing on the surface (grating, groove width 2 mm, groove pitch 15 mm, groove depth 0.6 mm), and a double-sided tape was attached to the opposite side to form a polishing pad.

 (Example 4)

 Plate 1 was machined into a rectangular piece with a length of 56 mm and a width of 19 mm and a radius (curvature radius of 1.0 mm) at the corner. Next, the plate material 3 was processed into a disk shape of φ500 mm in the same manner as in Example 3, and a groove was formed on the surface thereof. A rectangular hole with a radius of 56 mm and a width of 19 mm and a radius similar to the above was cut out at the midpoint of the radius from the center of the disk toward the circumference so that the longitudinal direction was on the radial side. A rectangular small piece made of the above-described plate material 1 was inserted into the hole of the disc to form a light detection transmission window. Finally, a double-sided tape was attached to the opposite side of the grooved surface to form a polishing pad. (Conventional example 1)

 A polishing pad made of foamed polyurethane resin, a commercially available product with a transparent window for light detection made of a rectangular transparent resin plate with a length of 56 mm and a width of 19 mm and a rounded corner was prepared. . (Thickness: 1.2 mm, Rodell's “IC-lOOOZSuba-400”)

 (Comparative Example 3)

 Plate 2 was processed in the same manner as in Example 3 to produce a polishing pad. (Reference example 1)

 Plate 3 was processed in the same manner as in Example 3 to produce a polishing pad. This polishing pad does not have a window as in the fourth embodiment.

The light transmittances of the polishing pads of these examples, conventional examples, reference examples and comparative examples were measured. For the polishing pad with a light-transmitting window, the measurement was performed at the window, and for the polishing pad without the light-transmitting window, the measurement was performed on the plate material of the polishing pad body. The transmittance was measured using a spectrophotometer UV-2200 manufactured by Shimadzu Corporation at a wavelength of 670 nm. The measured value was converted into a transmittance at a plate thickness of l mm using Lambert-Beer's law. The polishing device used was a MIRRA machine manufactured by Applied Materials of the United States, and these polishing pads were attached and fixed on a φ500 mm platen. The polishing pad with a light-transmitting window for light detection was adjusted so that the window of the polishing pad and the window of the polishing pad did not shift. After each polishing pad is attached to the surface plate, the pad conditioner attached to this polishing machine is used to attach a diamond dresser made by Asahi Diamond Co., Ltd. (Abrasives: # 170 Acryl Coat) Was attached, and dressing was performed at 9 LB for 15 minutes. At this time, the surface condition of each polishing pad was observed. As a result, the polishing pads of Example 3 and Reference Example 1 exhibited fiber exposure (exposure length: around 500 / zm). In the polishing pad of Example 4, similar fiber exposure (exposure length: front and rear) was observed on the entire surface of the pad including the window. In the polishing pads of Conventional Example 1 and Comparative Example 3, these fibers were not exposed.

 Table 3 summarizes the structures, surface states, and light transmittances of the polishing pads of these examples, conventional examples, reference examples, and comparative examples.

 Table 3

Polishing of silicon wafers (insulating film blanket wafers and TEG wafers) using the polishing pad and CMP polishing solution of each of the examples, conventional examples, reference examples, and comparative examples set in the polishing apparatus as described above. As The characteristics were evaluated from the following viewpoints. Table 4 shows the evaluation results.

 (Evaluation of the number of polishing scratches)

 A planket wafer having a silicon oxide film formed on a Φ200 mm silicon wafer by TE〇S—plasma CVD method at 1 μπι was set in a polishing apparatus. At this time, the wafer was held by the head portion, and the surface of the silicon oxide film was in contact with the polishing pad on the surface plate. The polishing pressure applied to the surface of the wafer during polishing was set at 21 kPa (3 PSI), and a supply amount of a cerium oxide-based polishing solution (HS-805, manufactured by Hitachi Chemical Co., Ltd.) was supplied. While mixing O mLZmin and an additive (HS-8101GP manufactured by Hitachi Chemical Co., Ltd.) with a supply amount of 16 OmLZmin, drop the mixture onto the platen while dropping it on the platen. The silicon oxide film on the wafer was polished for 1 minute by rotating the rpm and the head at 90 rpm. After the polished silicon wafer was sufficiently washed with pure water and dried, the entire surface of the wafer was observed with a microscope in a dark-vision field, and polishing scratches were counted.

 (Evaluation of polishing rate)

 The silicon oxide film thickness of each blanket wafer after the evaluation of the number of polishing scratches was measured by a light interference type film thickness measuring device, and the average polishing rate was determined from the difference from the silicon oxide film thickness measured before polishing.

 (Evaluation of uniformity)

 As in the measurement of the polishing rate, the polishing rate of the silicon oxide film at each point was measured at 45 points at every 5 mm to 8 mm at the end on the perpendicular diameter in the eight planes of each blanketway, and the standard deviation ( The variation in polishing rate (1δδaverage polishing rate XI 00) was determined from 15).

 (Evaluation of availability of endpoint management)

Φ 20 O mm A silicon nitride wafer with a thickness of 100 nm is formed by patterning a line with a width and spacing of 25 to 200 O zm on a silicon wafer. After forming the film, the exposed Si portion was etched to a depth of 35 O nm, and a silicon oxide film of 600 nm was formed on this wafer by TEOS-plasma CVD method. Prepared TEG wafers. When this wafer is polished under the same conditions as the above-mentioned blanket wafer, an IS RM end point management system using laser light attached to the polishing machine used for evaluation (MIRRA manufactured by Applied Material Technology) is used. Then, it was determined whether the exposure of the silicon nitride film could be detected.

 (Evaluation of flatness)

 Exposure of the silicon nitride film was detected by the end point management described above, and the line of the silicon nitride film (width 100 / zm) and the line of the silicon oxide film adjacent to the TEG wafer (width 3) were polished. 0 m) was measured using a stylus-type step gauge Dektak 300 (manufactured by SLOAN).

 Table 4

From the results of Examples 3 and 4 in Table 4, the use of the polishing pad according to the present invention enables the end point to be controlled by light detection. It can be understood that the effect of polishing can suppress the generation of polishing scratches. At this time, it was found that the polishing rate was high and the uniformity was sufficient. When polishing the TEG wafer used in the evaluation, the polishing pad of Reference Example 1 detects the end point by light irradiation. There was no noticeable change in reflectivity to know. This corresponds to the fact that the polishing pad of Reference Example 1 resulted in low light transmittance in the previous study.

 Next, examples regarding the maximum exposed fiber length will be described.

 (Example 5)

The following varnish is impregnated into a non-woven fabric of unit weight 70 g / m ² (“EPM — 470 TEJ” manufactured by Japan Vilean Co., Ltd.) made of polyester fiber with a fiber diameter of 12.5 m and a fiber length of 5 mm. Then, it was dried at 170 ° C. for 5 minutes to prepare a pre-preda.

 The varnish was prepared by adding 20 parts by weight of dicyandiamide as a curing agent and 0.1 part by weight of 2-ethyl-4-methylimidazole as a curing accelerator to 100 parts by weight of bisphenol A-type epoxy resin, and adding 4.0 parts by weight of methyl ethyl ketone. It was prepared by dissolving in parts by weight.

 Twenty sheets of the above prepredder were laminated, release films (polypropylene, 50 m thick) were placed on the top and bottom, and sandwiched between mirror plates. It was heated and pressed between press hot plates through a 10 mm thick cushion paper. Here, the molding conditions were set at 175 ° C, 400 kPa, and 120 minutes. As a result, a laminate having a thickness of 1.5 mm was obtained. The fiber content of the entire laminate was 50% by weight. This was cut out into a circle, and the surface was cut using a # 70 diamond whetstone, and then the grooves were processed to form a polishing pad. Here, a grid-like groove having a width of 2 mm, a depth of 0.6 mm, and a pitch of 15 mm was formed.

 (Example 6)

A laminated plate having a thickness of 1.5 mm was obtained in the same manner as in Example 5, except that 10 sheets of the prepregs shown in Example 5 and 10 sheets of non-resin-impregnated polyester nonwoven fabric were alternately laminated. The fiber content of the entire laminate was 70% by weight. After that, the surface is cut in the same way as in Example 5 and the groove is machined. This was used as a polishing pad.

 (Example 7)

Polyester fabric unit mass 1 ³ 0 g / m 3 as a fiber (manufactured by Asahi Kasei Corporation, "BKE potpourri down", fiber diameter: 9 m) but using the polishing pad in the same manner as in Example 5 Produced. In this example, the fiber content of the entire laminate was 50% by weight.

 (Example 8)

 Polyester fiber (produced by Nippon Pyreen Co., Ltd.) with a fiber diameter of 12.5 m and a fiber length of 3 mm as organic fiber, and ABS resin pellets as a matrix resin are melt-mixed by an extrusion molding machine. It has become a tablet. Here, the fiber content was adjusted to be 10% by weight. After drying the tablet at 120 ° C for 5 hours using a large-sized dryer, a sheet-like molded product having a thickness of 1.2 mm and a width of lm was produced by extrusion and rolls. A rectangular cross-sectional groove having a depth of 0.6 mm and a width of 2. O mm was formed in a grid pattern with a pitch of 15 mm, and then cut into a circle. Furthermore, after bonding a double-sided tape to the opposite side of the grooved surface, the surface was roughened using a # 70 diamond whetstone to obtain a polishing pad. (Reference example 2)

As a nonwoven fabric, a para-aramid fiber chop (fiber diameter: 12.5 Hm, fiber length: 5 mm, Teijin's Technora) and a meta-para-aramid fiber fiber Water-soluble epoxy resin binder (Dainippon Ink Chemical Industry Co., Ltd.) mixed with a nip (fiber diameter: 25 nm, fiber length: 6 mm, "Conex" manufactured by Teijin Limited) Sprayed with an aqueous solution of 20% by weight (trade name: “V Coat”), and dried by heating at 150 ° C. for 3 minutes to obtain a non-woven fabric of 70 g / m ² . A polishing pad was prepared in the same manner as in Example 5, except that the material was passed through a hot roll at a temperature of ° C and a linear pressure of 196 kNZm and heated and compressed. Also, The surface was cut using a # 150 diamond whetstone. In this reference example, the fiber content of the entire laminate was 50% by weight.

 (Comparative Example 4)

 A 1.5 mm thick ABS (acrylonitrile-butadiene rubber-styrene copolymer) plate was cut out into a circle and the groove width was 2 mm, the depth was 0.6 mm, and the pitch was on the surface. A 15 mm grid-like groove was machined. Then, the surface was roughened using a # 70 diamond whetstone to obtain a polishing pad.

 (Reference example 3)

 A polishing pad was prepared in the same manner as in Example 8, except that the surface was ground using a # 70 diamond grindstone.

 (Surface observation)

 Using a scanning electron microscope (SEM), five arbitrary points on the pad surface were observed at 100 × and 200 × magnification, and the maximum length of the exposed fiber was measured.

 (Polishing liquid)

 A CMP slurry was prepared as a polishing liquid by the following method.

 2 kg of cerium carbonate hydrate was placed in a platinum container, and 1 kg of cerium oxide powder obtained by calcining in air at 800 ° C for 2 hours was subjected to dry grinding using a jet mill. Was. To this, 23 g of an aqueous solution of polyacrylic acid ammonium salt (40% by weight) and 8977 g of deionized water were mixed, and subjected to ultrasonic dispersion for 10 minutes while stirring. The obtained slurry was filtered through a 1-micron filter, and deionized water was added to obtain a 5 wt% slurry. The slurry pH was 8.3. As a result of diluting the slurry particles to an appropriate concentration for measurement with a laser diffraction type particle size distribution analyzer, D9.9% of the particle diameter was 0.99 m.

(Evaluation of polishing method and polishing characteristics) W

36

A blanket wafer with a silicon oxide film formed 2 / m by TEOS-plasma CVD on a Φ127 mm Si substrate and a trench with square protrusions on a Φ200 mm Si substrate were provided. A test wafer was prepared on which a Si ₃ N ₄ film and a silicon oxide film of 600 m were formed 5 by TEOS-plasma CVD method. The wrench used was a 0.35 m deep, 60% convex, and 500 m wide wrench.

The wafer is set on a holder to which a suction pad for attaching a wafer substrate is attached, and the insulating film surface is placed on a Φ380 mm platen to which the polishing pad prepared above is attached. The work load was set to 29 kPa (300 gf / cm ² ).

 While the cerium oxide polishing solution was dropped on the platen at a rate of 150 c, the platen and the wafer were rotated at 38 rpm for 2 minutes to polish the insulating film. The polished wafer was thoroughly washed with pure water and then dried. The difference in film thickness before and after polishing was measured using a light interference type film thickness measuring device, and the polishing rate was calculated as L5. With respect to the polishing scratches, the wrought ueno and surface were observed with a microscope in a dark-vision field, and the scratches caused by the polishing on the surface were counted.

For the evaluation of flatness, a step of 1 zm between the convex and concave portions of the TEG wafer was cut, and the final step before the convex Si ₃ N ₄ film was exposed was measured. In addition, dishing was measured on the above-mentioned trench portion of the TEG wafer with a stylus-type step difference meter!

 Table 5 shows the polishing characteristics of Examples, Reference Examples and Comparative Examples. In Examples 5, 6, 7, and 8 including the polyester fiber according to the present invention, the exposed fiber length was easily reduced and the flatness was improved as compared with Reference Example 2 including the aramide fiber which was a high-hardness fiber. Excellent, no polishing scratches. Also, when Examples 5, 6, 57 and 8 are compared with Comparative Example 4 containing no fiber, the polishing rate is improved and polishing scratches are eliminated.

Table 5 If r

 mf ¾e.! f ^ f.rip

 m

 Fiber length Flatness

 (nffl / m l n) (pcs / ゥ Λ)

 (m) (nm) Example 5 1 0 2 1 0 0 2 0 2 5 Example 6 1 0 2 4 0 0 2 0 2 8 Example 7 1 0 2 4 0 0 2 0 2 9 Example 8 1 0 2 2 0 1 0 3 0 2 5 Reference example 2 5 0 1 9 0 4 0 2 0 4 0 Comparative example 4 0 1 0 2 5 0 Measurement impossible Measurement impossible Reference example 3 1 5 0 3 5 0 0 5 0 5 0

 From Table 5, it can be seen that the use of a polishing pad with a maximum exposed fiber length of 0.1 mm or less can improve the flatness without polishing scratches and the anti-denting property of the trench, and improve the interlayer insulating film and BPSG film. It can be seen that the semiconductor formation process including flattening and shallow-trench separation can be efficiently performed.

Industrial potential

 If CMP is performed using the polishing pad of the present invention or the polishing pad manufactured by the manufacturing method of the present invention, fine organic material exposed on the surface of the polishing pad on the object to be polished allows fine polishing of the object to be polished. The occurrence of polishing scratches can be suppressed. Thereby, flat polishing can be performed with a low load. Moreover, the polishing end point of the object to be polished by the system for detecting the state of polishing of the object to be polished by an optical method can be managed without polishing scratches. As a result, it is possible to improve the productivity and yield of the object to be polished.

 For this reason, for example, in a semiconductor device manufacturing process, polishing with a small load on the interlayer insulating film and excellent flatness can be performed, and the next-generation dual damascene method can be easily performed.

Claims

 The scope of the claims 1-A polishing pad comprising a fiber containing an organic fiber and a matrix resin holding the fiber, wherein at least the organic fiber is exposed on the surface of the object to be polished.  2. A fiber comprising organic fibers and a matrix resin holding the fibers, wherein at least the organic fibers are exposed on the surface to be polished after the dressing treatment. Polishing pad.  3. The polishing pad according to claim 1, wherein the matrix resin contains at least one kind of thermoplastic resin.  4. The polishing pad according to any one of claims 1 to 3, wherein the matrix resin comprises a semi-crystalline thermoplastic resin.  5. The polishing pad according to any one of claims 1 to 4, wherein the elastomer is dispersed in the matrix resin. 6. The polishing pad according to claim 5, wherein the elastomer has a glass transition point of 0 ° C. or lower.  7. The polishing pad according to any one of claims 1 to 6, wherein the fiber is made of an aromatic polyamide.  8. The polishing pad according to any one of claims 1 to 7, wherein the polishing pad contains 1 to 50% by weight of an organic fiber.  9. The polishing pad according to any one of claims 1 to 8, wherein the diameter of the organic fiber is 1 mm or less.  10. The polishing pad according to any one of claims 1 to 9, wherein the length of the organic fiber is 1 cm or less. 11. The polishing pad according to any one of claims 1 to 10, wherein the polishing particles are held by organic fibers exposed on the surface of the object to be polished. 1 2. The maximum length of the exposed organic fiber is 0.1 mm or less. The polishing pad according to any one of claims 1 to 11, wherein the polishing pad is: 13. The polishing pad according to claim 12, wherein the exposed organic fibers are made of polyester.  14. The polishing pad according to claim 12 or 13, wherein chopped polyester fibers are dispersed 5 in a matrix resin.  15. The polishing pad according to claim 12, wherein the polyester nonwoven fabric is laminated in a matrix resin.  16. A polishing pad that is useful for optically detecting the polishing end point during polishing of the surface of the object to be polished, and is a substantially non-foaming matrix containing 1 to 20% by weight of organic fibers. Claims 1 and 2 which are made of a trix resin, have a function of transporting and holding polishing slurry particles, and transmit light having a wavelength in the range of 190 to 350 nm. A polishing pad according to any one of the above-mentioned items 4 to 7, 7 and 9 to 11.  17. A polishing pad that is useful for optically detecting the polishing end point while polishing the surface of the workpiece, and that transmits light with a wavelength in the range of 190 to 350 nm. A portion comprising a substantially non-foamed matrix resin containing 1 to 20% by weight of organic fibers and having a function of transporting and holding polishing slurry particles. The polishing pad according to any one of the above items 1, 2 to 4, 7 and 9 to 11.  18. The polishing pad according to claim 16, wherein the organic fiber is an aramide fiber. 1 9. This is a method of manufacturing a polishing pad that is used by attaching it to a surface plate and flattening the surface to be polished, by mixing fibers containing organic fibers with a matrix composition containing thermoplastic resin. To obtain a mixture, a step of forming the mixture into a pellet or an evening plate, and a step of extruding the pellet or the evening plate into a plate or sheet by extrusion or injection molding. A method for producing a polishing pad, comprising a step of polishing.  20. A method for manufacturing a polishing pad that is used by attaching it to a surface plate to flatten the surface to be polished, and impregnating a fiber base material containing organic fibers with a matrix resin composition to impregnate the resin. Polishing characterized by including a step of producing a sheet-like fiber base material, a step of laminating the sheet-like fiber base material including the resin-impregnated sheet-like fiber base material, and applying heat and pressure molding. Pad manufacturing method.  21. The method for producing a polishing pad according to claim 19 or claim 20, further comprising a step of exposing the fiber to the surface.  22. The polished surface of the object to be polished is pressed against the organic fiber exposed surface of the polishing pad according to any one of claims 1 to 18, and a polishing liquid is applied between the polished surface and the polishing pad. A polishing method in which an object to be polished and a pad are slid relative to each other while being supplied during polishing, thereby polishing the surface to be polished.  23. The method according to claim 22, wherein the surface to be polished is formed by laminating a conductor layer and a copper layer on an insulating layer having a dielectric constant of 2.7 or less, on which wirings and trenches are formed. Polishing method.  24. A polishing method for optically detecting a polishing end point using the polishing pad according to any one of claims 16 to 18.