JP2009066728A - Chemical-mechanical polishing pad, and chemical-mechanical polishing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a chemical-mechanical polishing pad with a long product life by which a damage on a polishing layer during chemical-mechanical polishing is suppressed, and a chemical-mechanical polishing method using the pad. <P>SOLUTION: The chemical-mechanical polishing pad 10 is fixed on a polishing plate 13 of a polishing device, and includes the polishing layer 11 and a cushioning layer 14 arranged between the polishing layer 11 and the polishing device surface plate. The cushioning layer 14 is provided with a through hole 20 in an area including the center part of the polishing layer 11. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a chemical mechanical polishing pad and a chemical mechanical polishing method.

  In recent years, in the formation of semiconductor devices, a surface having excellent flatness can be formed on a silicon substrate or a silicon substrate (hereinafter referred to as “semiconductor wafer”) on which wirings, electrodes, and the like are formed. As a polishing method, a chemical mechanical polishing method (Chemical Mechanical Polishing, generally abbreviated as “CMP”) has attracted attention. In the chemical mechanical polishing method, a chemical mechanical polishing aqueous dispersion (an aqueous dispersion in which abrasive grains are dispersed; slurry) flows down on the pad surface while sliding the chemical mechanical polishing pad and the surface to be polished. It is a technique to perform. In this chemical mechanical polishing method, it is known that the polishing result greatly depends on the properties and characteristics of the chemical mechanical polishing pad, and various chemical mechanical polishing pads have been proposed.

  For example, a polyurethane foam containing fine bubbles is used as a chemical mechanical polishing pad, and polishing is performed by holding a chemical mechanical polishing aqueous dispersion in a hole (hereinafter referred to as “pore”) opened on the surface of the pad. The chemical mechanical polishing pad has been known for a long time. (For example, refer patent documents 1-3.).

  By the way, when polishing the surface to be polished by the chemical mechanical polishing method, a polishing head having a retainer ring for holding a semiconductor wafer is generally used. In order to achieve the target polishing rate, it may be necessary to press the semiconductor wafer against the polishing pad at high pressure. In such a case, the retainer ring pressure is increased, and cracks or defects are given to the grooves on the polished surface. Generally, since the polishing head swings on the polishing pad during chemical mechanical polishing, the cracks and defects are accelerated by the swing. Damages such as cracks and defects are extremely frequent especially at the center of the polishing pad. Such cracks and defects may cause scratch-like defects called “scratches” on the surface of the surface to be polished. When cracks or defects occur, it is necessary to replace them with new chemical mechanical polishing pads. was there.

Therefore, in order to prevent the occurrence of scratches or the like and extend the life of the polishing pad, a chemical mechanical polishing pad in which a recess is provided on the non-polishing surface side of the polishing layer has been proposed (see Patent Document 4). .
JP-A-11-70463 JP-A-8-216029 JP-A-8-39423 JP 2004-345048 A

  The present invention solves the above-mentioned problems, and an object thereof is to provide a chemical mechanical polishing pad capable of suppressing damage to the polishing layer during chemical mechanical polishing and having a long product life. It is to provide a high-quality chemical mechanical polishing method for a long time by using a mechanical polishing pad.

The chemical mechanical polishing pad according to the first aspect of the present invention is:
A chemical mechanical polishing pad for fixing to a polishing apparatus surface plate,
A polishing layer;
Having a cushion layer provided between the polishing layer and the polishing apparatus surface plate,
The cushion layer has a through hole in a region including a central portion of the polishing layer.

The chemical mechanical polishing pad according to the second aspect of the present invention is:
A chemical mechanical polishing pad for fixing to a polishing apparatus surface plate,
A polishing layer;
A first adhesive layer, a cushion layer, and a second adhesive layer, which are provided between the polishing layer and the polishing apparatus surface plate and provided in order from the polishing layer side;
The first adhesive layer adheres the polishing layer to the cushion layer,
The second adhesive layer adheres the cushion layer to the polishing apparatus surface plate,
The cushion layer is thicker than the first adhesive layer and the second adhesive layer,
Each of the first adhesive layer, the cushion layer, and the second adhesive layer has a through hole in a region including the central portion of the polishing layer.

  In the chemical mechanical polishing pad, the through hole may be circular.

  The chemical mechanical polishing pad according to the present invention uses the chemical mechanical polishing pad.

  ADVANTAGE OF THE INVENTION According to this invention, the chemical mechanical polishing pad which can suppress the damage of a polishing layer during chemical mechanical polishing and has a long product life is provided, and high quality is achieved by using the chemical mechanical polishing pad. A chemical mechanical polishing method is provided for a long time.

1. Chemical Mechanical Polishing Pad FIG. 1 is a cross-sectional view showing a chemical mechanical polishing pad according to the present embodiment. The chemical mechanical polishing pad 10 according to the present embodiment is provided with a polishing layer 11, a cushion layer 14 provided between the polishing layer 11 and the polishing apparatus surface plate 13, and between the polishing layer 11 and the cushion layer 14. The first adhesive layer 12 and the second adhesive layer 15 provided between the cushion layer 14 and the polishing apparatus surface plate 13 are included. That is, the chemical mechanical polishing pad 10 includes the second adhesive layer 15, the cushion layer 14, the first adhesive layer 12, and the polishing layer 11 provided in this order from the polishing apparatus base plate 13 side.

  Each of the second adhesive layer 15, the cushion layer 14, and the first adhesive layer 12 has through holes 20, 22, and 24 in a region A including the central portion of the polishing layer 11.

  The planar shapes of the through holes 20, 22, 24 are the same as each other and are preferably circular, and the diameter thereof is 10 to 200 mm, more preferably 20 to 100 mm. In addition, the “region including the central portion” means that the center of gravity of the through holes 20, 22, 24 coincides with the center of gravity of the non-polished surface in a mathematically exact sense, and the center of gravity of the non-polished surface of the polishing layer 11 is It is a concept that includes the case where it is located within the range of the through holes 20, 22, and 24.

  As described above, the second adhesive layer 15, the cushion layer 14, and the first adhesive layer 12 of the chemical mechanical polishing pad 10 have the through holes 20, 22, and 24 in the region A including the central portion, so that the center The frequency of occurrence of cracks and defects in the part can be reduced. In particular, by having the cushion layer 14, the distance between the polishing layer 11 and the polishing apparatus surface plate 13 is widened, and the polishing layer 11 is deformed by the pressure from the polishing surface side and polished inside the through holes 20, 22, 24. Contact with the apparatus surface plate 13 can be prevented.

  The shape of the chemical mechanical polishing pad 10 according to the present embodiment is not particularly limited. For example, the chemical mechanical polishing pad 10 can be a disc shape, a polygonal column shape, or the like, and is appropriately selected according to the polishing apparatus to which the chemical mechanical polishing pad 10 is attached. Can do.

  The total thickness of the second adhesive layer 15, the cushion layer 14, and the first adhesive layer 12 is preferably 0.3 mm to 3.0 mm, and preferably 0.5 mm to 1.5 mm. Is more preferable.

  Next, the materials and shapes of the cushion layer 14, the polishing layer 11, and the first and second adhesive layers 12 and 15 will be described in detail.

1.1. Cushion Layer The cushion layer 14 is a layer that supports polishing on the back side of the polishing surface, and is provided between the polishing layer 11 and the polishing apparatus surface plate 13. As described above, the cushion layer 14 has the through hole 22 in the region A including the central portion of the polishing layer 11. The characteristics of the cushion layer 14 are not particularly limited, but the hardness is lower than that of the polishing layer 11. By providing the cushion layer 14 having a hardness lower than that of the polishing layer 11, the polishing layer 11 may be lifted during polishing or the surface of the polishing layer 11 even when the thickness of the polishing layer 11 is small, for example, 1.0 mm or less. Can be prevented from being bent, and stable polishing can be performed.

  Specifically, the hardness of the cushion layer 14 is preferably 20 to 70 in Shore A hardness, and more preferably 25 to 60. Since the cushion layer 14 has such low hardness and elasticity, even when an excessive pressure is applied to the polishing layer 11 during polishing, the pressure can be relaxed and the life of the polishing layer 11 can be extended. . Specifically, the material of the cushion layer 14 is preferably, for example, foamed polyurethane.

  The cushion layer 14 may be a porous body (foam) or a non-porous body. The planar shape of the cushion layer 14 only needs to have at least the above-described through-hole 22, and the shape is not particularly limited. The planar shape of the cushion layer 14 may be, for example, a circle or a polygon.

  For example, the thickness of the cushion layer 14 is preferably 0.1 mm to 5.0 mm, and more preferably 0.5 mm to 2.0 mm. The cushion layer 14 is formed thicker than the first adhesive layer 12 and the second adhesive layer 15. By having such a thickness, the cushion layer 14 can sufficiently exhibit the function of relieving pressure.

1.2. Polishing Layer The polishing layer 11 may be made of any material as long as it has a function as the chemical mechanical polishing pad 10 as long as it has the above requirements. Among the functions of the chemical mechanical polishing pad 10, in particular, pores (fine pores) having functions such as holding the chemical mechanical polishing aqueous dispersion and temporarily retaining polishing waste during chemical mechanical polishing are polished. It is preferable that it is formed by time. Therefore, (I) a water-insoluble member and a material composed of water-soluble particles dispersed in the water-insoluble member, or (II) a material composed of a water-insoluble member and pores dispersed in the water-insoluble member. It is preferable to provide.

Of these, the material (I) is formed into a water-insoluble member by the water-soluble particles coming into contact with the chemical mechanical polishing aqueous dispersion and dissolving or swelling during the chemical mechanical polishing step. It is possible to hold the chemical mechanical polishing aqueous dispersion in the pores, while the material (II) has a holding capacity of the chemical mechanical polishing aqueous dispersion or the like in the portion formed in advance as pores. .

  Hereinafter, these materials will be described in detail.

(I) Material comprising water-insoluble member and water-soluble particles dispersed in water-insoluble member (A) Water-insoluble member The material constituting the water-insoluble member (A) is not particularly limited. An organic material is preferably used because it can be easily formed into a shape and properties, and can be provided with appropriate hardness, appropriate elasticity, and the like. Examples of the organic material include thermoplastic resin, elastomer or raw rubber, and cured resin.

  Examples of the thermoplastic resin include olefin resins (for example, polyethylene and polypropylene), styrene resins (for example, polystyrene), acrylic resins (for example, (meth) acrylate resins), vinyl ester resins (however, (meth)). Examples thereof include those not corresponding to acrylate resins), polyester resins (excluding those corresponding to vinyl ester resins), polyamide resins, fluororesins, polycarbonate resins, polyacetal resins, and the like.

  Examples of the elastomer or raw rubber include diene elastomers (for example, 1,2-polybutadiene), olefin elastomers (for example, dynamically cross-linked ethylene-propylene rubber and polypropylene resin, etc.), urethane elastomers, urethane rubbers ( For example, urethane rubber, etc., styrene-based elastomers (for example, styrene-butadiene-styrene block copolymer (hereinafter sometimes referred to as “SBS”), hydrogenated products of styrene-butadiene-styrene block copolymer (hereinafter referred to as “ SEBS ”)), conjugated diene rubbers (eg, high cis butadiene rubber, low cis butadiene rubber, isoprene rubber, styrene-butadiene rubber, styrene-isoprene rubber, acrylonitrile-butadiene rubber, chloroprene rubber, etc.) , Ethylene-α-olefin rubber (for example, ethylene-propylene rubber, ethylene-propylene-nonconjugated diene rubber), butyl rubber, and other rubbers (for example, silicone rubber, fluorine rubber, nitrile rubber, chlorosulfonated polyethylene, acrylic rubber, epichlorohydrin rubber) , Polysulfide rubber, etc.).

  Examples of the cured resin include a thermosetting resin, a photocurable resin, and the like. Examples of these resins include a urethane resin, an epoxy resin, an unsaturated polyester resin, a polyurethane-urea resin, a urea resin, a silicon resin, and a phenol resin. Etc.

  These organic materials may be used alone or in combination of two or more.

  These organic materials may be modified so as to have an appropriate functional group. Examples of suitable functional groups include groups having an acid anhydride structure, carboxyl groups, hydroxyl groups, epoxy groups, amino groups, and the like.

These organic materials are preferably partially or wholly crosslinked. By containing the crosslinked organic material, the water-insoluble member is imparted with an appropriate elastic recovery force to the water-insoluble member, thereby suppressing displacement due to shear stress applied to the chemical mechanical polishing pad 10 during chemical mechanical polishing. it can. Further, during the chemical mechanical polishing step and dressing (the “sharpening” process of the chemical mechanical polishing pad 10 performed alternately or simultaneously with the chemical mechanical polishing), the water-insoluble member is excessively stretched and plastically deformed to cause pores. Further, it is possible to effectively suppress the embedding and excessive fuzz of the surface of the chemical mechanical polishing pad 10. Therefore, the pores are efficiently formed even during dressing, the retention of the chemical mechanical polishing aqueous dispersion at the time of polishing can be prevented from being lowered, and further, the chemical mechanical polishing pad 1 can be maintained for a long time with less fuzz and polishing flatness.
0 can be obtained.

  Examples of the crosslinked organic material include a crosslinked thermoplastic resin and a crosslinked elastomer or a crosslinked rubber (herein, “crosslinked rubber” means a crosslinked product of the “raw rubber”). More preferably, it contains at least one selected from the group consisting of a crosslinked diene elastomer, a crosslinked styrene elastomer, and a crosslinked conjugated diene rubber. At least one selected from crosslinked 1,2-polybutadiene, crosslinked SBS, crosslinked SEBS, crosslinked styrene butadiene rubber, crosslinked styrene-isoprene rubber and crosslinked acrylonitrile-butadiene rubber. It is particularly preferred to contain a crosslinked 1,2-polybutadiene Desirably contains at least one selected from among crosslinked SBS and crosslinked SEBS.

  When a part of the organic material is cross-linked and the other part is non-cross-linked, the non-cross-linked organic material includes non-cross-linked thermoplastic resin and non-cross-linked elastomer or raw rubber. It is preferable to contain at least one selected from the group consisting of non-crosslinked olefin resin, non-crosslinked styrene resin, non-crosslinked diene elastomer, non-crosslinked styrene elastomer, non-crosslinked conjugated diene rubber, and non-crosslinked It is more preferable to contain at least one selected from the group consisting of butyl rubber, non-crosslinked polystyrene, non-crosslinked 1,2-polybutadiene, non-crosslinked SBS, non-crosslinked SEBS, non-crosslinked styrene-butadiene rubber, non-crosslinked At least one selected from cross-linked styrene-isoprene rubber and non-cross-linked acrylonitrile-butadiene rubber. More preferably contains, non-crosslinked polystyrene, non-crosslinked 1,2-polybutadiene, it is particularly preferred to contain at least one selected from among non-crosslinked SBS and uncrosslinked SEBS.

  When a part of the organic material is cross-linked and the other part is non-cross-linked, the ratio of the cross-linked organic material in the water-insoluble member is 30% by mass or more. Is more preferable, it is more preferable that it is 50 mass% or more, and it is especially preferable that it is 70 mass% or more.

  When the organic material is partially or wholly crosslinked, the crosslinking method is not particularly limited, and for example, a chemical crosslinking method, a radiation crosslinking method, a photocrosslinking method, or the like can be used. The chemical crosslinking method can be performed using, for example, an organic peroxide, sulfur, a sulfur compound, or the like as a crosslinking agent. The radiation crosslinking method can be performed by a method such as electron beam irradiation. The photocrosslinking method can be performed by a method such as ultraviolet irradiation.

  Among these, it is preferable to use a chemical crosslinking method, and it is more preferable to use an organic peroxide because it has good handling properties and does not contaminate an object to be polished in the chemical mechanical polishing step. Examples of the organic peroxide include dicumyl peroxide, diethyl peroxide, di-t-butyl peroxide, diacetyl peroxide, and diacyl peroxide.

  When the crosslinking is performed by a chemical crosslinking method, the amount of the crosslinking agent used is preferably 0.01 to 0.6 parts by mass with respect to 100 parts by mass of the total amount of the water-insoluble member subjected to the crosslinking reaction. By setting the amount used within this range, it is possible to obtain the chemical mechanical polishing pad 10 in which the generation of scratches is suppressed in the chemical mechanical polishing step.

  The cross-linking may be performed collectively for all the materials constituting the water-insoluble member, or may be mixed with the remainder after cross-linking is performed on a part of the material constituting the water-insoluble member. Moreover, you may mix several types of crosslinked material which performed each bridge | crosslinking.

  Further, when the cross-linking is based on a chemical cross-linking method, the amount of cross-linking agent used and the cross-linking conditions are adjusted. By the operation, it is possible to easily obtain a mixture of organic materials partially cross-linked and other parts non-cross-linked.

  The (A) water-insoluble member contains an appropriate compatibilizing agent in order to control the affinity with the water-soluble particles (B) described later and the dispersibility of the (B) water-soluble particles in the water-insoluble member. be able to. Examples of the compatibilizer include nonionic surfactants and coupling agents.

(B) Water-soluble particles (B) The water-soluble particles are detached from the water-insoluble member by contact with the chemical-mechanical aqueous dispersion in the chemical mechanical polishing pad 10 to form pores in the water-insoluble member. In addition, it has the effect of increasing the indentation hardness of the polishing substrate of the chemical mechanical polishing pad 10 and realizes the Shore D hardness of the polishing substrate described above.

  The desorption is caused by dissolution, swelling, or the like due to contact with water or an aqueous mixed medium contained in the chemical mechanical polishing aqueous dispersion.

  (B) The water-soluble particles are preferably solid in order to secure the indentation hardness of the polishing layer 11 of the chemical mechanical polishing pad 10 described above. Therefore, the water-soluble particles are particularly preferably solid bodies that can ensure sufficient indentation hardness in the chemical mechanical polishing pad 10.

  (B) Although the material which comprises water-soluble particle | grains is not specifically limited, Organic water-soluble particle | grains and inorganic water-soluble particle | grains can be mentioned. Examples of the organic water-soluble particles include sugars (polysaccharides (eg, starch, dextrin, cyclodextrin, etc.), lactose, mannitol, etc.), celluloses (hydroxypropylcellulose, methylcellulose, etc.), proteins, polyvinyl alcohol, polyvinylpyrrolidone, Examples thereof include polyacrylic acid, polyethylene oxide, water-soluble photosensitive resin, sulfonated polyisoprene, and sulfonated polyisoprene copolymer. Examples of the inorganic water-soluble particles include potassium acetate, potassium nitrate, potassium carbonate, potassium hydrogen carbonate, potassium chloride, potassium bromide, potassium phosphate, and magnesium nitrate. Among these, organic water-soluble particles are preferable, polysaccharides are more preferable, cyclodextrins are further preferable, and β-cyclodextrin is particularly preferable.

  These water-soluble particles may be used alone or in combination of two or more. Further, it may be one type of water-soluble particles made of a predetermined material, or two or more types of water-soluble particles made of different materials.

  (B) The average particle diameter of the water-soluble particles is preferably 0.1 to 500 μm, more preferably 0.5 to 100 μm. By using (B) water-soluble particles having a particle size in this range, the size of the pores generated by (B) desorption of the water-soluble particles can be controlled within an appropriate range. It is possible to obtain a chemical mechanical polishing pad 10 which is excellent in the retention capability and polishing rate of the chemical mechanical polishing aqueous dispersion and excellent in mechanical strength.

The content of (B) water-soluble particles is preferably 10 to 90% by volume, more preferably 15 to 60% by volume, based on the total of (A) water-insoluble member and (B) water-soluble particles. More preferably, it is 20-40 volume%. (B) By making content of water-soluble particle into this range, the chemical mechanical polishing pad 10 excellent in balance of mechanical strength and polishing rate can be obtained.

  The water-soluble particles (B) are dissolved or swollen in water only when exposed to the surface layer in contact with the chemical mechanical polishing aqueous dispersion in the chemical mechanical polishing pad 10, and in the polishing layer 11, the water soluble particles are released. It is preferable not to absorb moisture. For this reason, (B) water-soluble particle | grains may be provided with the outer shell which suppresses moisture absorption in at least one part of the outermost part. The outer shell may be physically adsorbed on the water-soluble particles, chemically bonded to the water-soluble particles, or may be attached to the water-soluble particles by both. Examples of the material for forming such an outer shell include epoxy resin, polyimide, polyamide, polysilicate, and the like.

(II) A material comprising a water-insoluble member and pores dispersed in the water-insoluble member The polishing layer 11 is composed of a water-insoluble member and pores dispersed in the water-insoluble member. Examples include foams such as polyurethane, melamine resin, polyester, polysulfone, and polyvinyl acetate.

  The average diameter of the pores dispersed in the water-insoluble member as described above is preferably 0.1 μm to 500 μm, more preferably 0.5 to 100 μm.

  The shape of the polishing layer 11 is not particularly limited. For example, the shape of the polishing layer 11 can be a disk shape, a polygonal column shape, or the like, and can be appropriately selected according to the polishing apparatus to which the chemical mechanical polishing pad 10 is attached.

  Although the size of the polishing layer 11 is not particularly limited, for example, in the case of a disk shape, the diameter is 150 to 1200 mm, particularly 500 to 800 mm, the thickness is 1.0 to 5.0 mm, and particularly the thickness is 1.5 to 3.0 mm. Can do.

  The polishing layer 11 of the chemical mechanical polishing pad 10 can have a groove on the polishing surface. This groove holds an aqueous dispersion for chemical machinery supplied during chemical mechanical polishing, distributes it uniformly on the polishing surface, and temporarily disposes wastes such as polishing waste and used aqueous dispersion. It has a function to be a path for staying and discharging outside.

  The shape of the groove is not particularly limited, and may be, for example, a spiral shape, a concentric circle shape, a radial shape, or the like. In the present embodiment, the groove preferably has a point-symmetric shape with the central portion of the polishing layer 11 as the center so that pressure is uniformly applied to the central portion.

  Moreover, it is preferable that the non-polishing surface side of the polishing layer 11 is formed flush. Thereby, mechanical strength can be maintained high. Moreover, since the non-polishing surface side is formed flush, the polishing layer 11 can maintain the degree of freedom of the groove forming region on the polishing surface side described above.

  Further, the chemical mechanical polishing pad 10 can include a portion having other functions in addition to the polishing portion. Examples of the part having other functions include a window part for detecting an end point using an optical end point detection device. As a window part, for example, at a thickness of 2 mm, the transmittance of light of any wavelength between 100 and 300 nm is 0.1% or more (preferably 2% or more), or a wavelength of 100 to 300 nm. A material having an integrated transmittance of 0.1% or more (preferably 2% or more) in any wavelength region between 3000 nm can be used. The material of the window portion is not particularly limited as long as it satisfies the optical characteristics described above. For example, the same composition as that of the polishing layer 11 described above can be used.

The method for producing the polishing layer 11 constituting the chemical mechanical polishing pad 10 is not particularly limited, and grooves and recesses that the polishing layer 11 may optionally have (hereinafter, both are collectively referred to as “grooves”). .) Is not particularly limited. For example, a chemical mechanical polishing pad composition to be the polishing layer 11 of the chemical mechanical polishing pad 10 is prepared in advance, and after this composition is formed into a desired shape, grooves and the like can be formed by cutting. . Further, by molding the chemical mechanical polishing pad composition using a mold in which a pattern to be a groove or the like is formed, the groove or the like can be formed simultaneously with the rough shape of the polishing layer 11.

  The method for obtaining the chemical mechanical polishing pad composition is not particularly limited. For example, necessary materials such as predetermined organic materials can be obtained by kneading with a kneader or the like. A conventionally known kneading machine can be used. Examples thereof include kneaders such as rolls, kneaders, Banbury mixers, and extruders (single screw and multi screw).

  The polishing pad composition containing water-soluble particles for obtaining the polishing pad 10 containing water-soluble particles can be obtained, for example, by kneading a water-insoluble matrix, water-soluble particles and other additives. . However, it is usually kneaded by heating so that it is easy to process during kneading, but the water-soluble particles are preferably solid at this temperature. By being solid, water-soluble particles can be dispersed at the above-mentioned preferable average particle diameter regardless of the compatibility with the water-insoluble matrix. Therefore, it is preferable to select the type of water-soluble particles according to the processing temperature of the water-insoluble matrix used.

1.3. Adhesive Layer The chemical mechanical polishing pad 10 according to the present embodiment includes a second adhesive layer 15 provided between the cushion layer 14 and the polishing apparatus surface plate 13, and between the cushion layer 14 and the polishing layer 11. And a first adhesive layer 12 provided. The second adhesive layer 15 is used for fixing the cushion layer 14 to the polishing apparatus surface plate 13. The first adhesive layer 12 is used for fixing the polishing layer 11 to the cushion layer 14. Further, the first adhesive layer 12 and the second adhesive layer 15 are preferably made of a material having a lower elastic modulus than the polishing layer 11. As a result, even if an excessive pressure is applied to the polishing layer 11 during polishing, the pressure can be relaxed and the life of the polishing layer 11 can be extended. In addition, since the first adhesive layer 12 having a low elastic modulus has the through-hole 20, the through-hole 20 side of the central portion is passed from the polishing layer 11 through the first adhesive layer 12 around the through-hole 20. Alternatively, by gradually lowering the elastic modulus toward the cushion layer 14, the step of the elastic modulus can be relaxed, the pressure in a wide range can be relaxed, and damage to the polishing layer 11 can be reduced.

  The first adhesive layer 12 can be made of, for example, an adhesive sheet. The thickness of the pressure-sensitive adhesive sheet can be, for example, 50 μm to 250 μm.

  As shown in FIG. 1, the first adhesive layer 12 and the second adhesive layer 15 have through holes 20 and 24 in a region A including the central portion of the polishing layer 11. The shapes of the through holes 20 and 24 are not particularly limited, but are preferably circular or polygonal with the center of the polishing layer 11 as the center of gravity.

  Since the first adhesive layer 12 and the second adhesive layer 15 have the through holes 20 and 24, even when air is caught when the release paper is peeled off from the adhesive sheet and fixed to the polishing machine surface plate, it is caught. Air can be expelled from the through holes 20, 24.

  The material of the pressure-sensitive adhesive sheet is not particularly limited as long as the polishing layer 11 and the cushion layer 14 can be fixed to the polishing machine surface plate, but acrylic and rubber systems having a lower elastic modulus than the polishing layer 11 are preferable, and more specific. Acrylic is preferable.

The adhesive strength of the adhesive sheet is not particularly limited as long as the chemical mechanical polishing pad can be fixed to the polishing machine surface plate. However, when the adhesive strength of the adhesive sheet is measured according to JIS B7059 standard, the adhesive strength is 4 N / CM. The above is preferable.

2. Chemical Mechanical Polishing Method The chemical mechanical polishing pad according to the embodiment can be attached to a commercially available polishing apparatus and used for the chemical mechanical polishing method by a known method. For example, a semiconductor device can be manufactured using such a chemical mechanical polishing method. Hereinafter, an example of a chemical mechanical polishing method using the above-described chemical mechanical polishing pad will be described.

  2 and 3 are views for explaining the chemical mechanical polishing method according to the present embodiment. In the chemical mechanical polishing method according to the present embodiment, the chemical mechanical polishing pad 10 rotates in the arrow D direction. The semiconductor wafer 30 is held by a holder 32 fixed to the pressure head. The semiconductor wafer 30 is rotated in the direction of the arrow B by the pressure head and vertically (in the radial direction between the center portion and the outside) as indicated by the arrow C direction. ). In this way, the semiconductor wafer 30 is slid and brought into contact with the chemical mechanical polishing pad 10 while being pressed, and the slurry is supplied onto the chemical mechanical polishing pad 10 to perform polishing.

  In the chemical mechanical polishing method according to the present embodiment, since the chemical mechanical polishing pad 10 having the through holes 20, 22, 24 is used, when the semiconductor wafer 30 is slid, the chemical mechanical polishing pad 10 is moved to the non-polished surface side in the direction of arrow E. Since the polishing layer 11 can be bent, it is possible to prevent an excessive pressure from being applied to the groove 40 in the vicinity of the central portion, and to maintain a uniform polished surface for a long period of time.

Examples of an object to be polished using the chemical mechanical polishing pad according to the embodiment include a metal as a wiring material, a barrier metal, and an insulating film. Examples of the metal include tungsten, aluminum, copper, and alloys containing these. Examples of the barrier metal include tantalum, tantalum nitride, titanium, titanium nitride, and tungsten nitride. Examples of the insulating film include a silicon oxide film (PETOS film (Plasma Enhanced-TEOS film), HDP film (High Density Plasma) formed by a vacuum process such as chemical vapor deposition.
Enhanced-TEOS film), silicon oxide film obtained by a thermal CVD method), a small amount of boron and boron phosphorus silicate film obtained by adding phosphorus (BPSG film SiO _2), FSG fluorine-doped SiO ₂ (Fluorine-doped Examples thereof include an insulating film called “silicate glass”, an insulating film called “SiON” (silicon oxide), silicon nitride, and a low dielectric constant insulating film.

As the low dielectric constant insulating film, for example, in the presence of oxygen, carbon monoxide, carbon dioxide, nitrogen, argon, H ₂ O, ozone, ammonia, alkoxysilane, silane, alkylsilane, arylsilane, siloxane, Insulating film made of polymer obtained by plasma polymerization of silicon-containing compounds such as alkylsiloxane, insulating film made of polysiloxane, polysilazane, polyarylene ether, polybenzoxazole, polyimide, silsesquioxane, etc., low dielectric constant The silicon oxide insulating film can be mentioned.

As described above, the chemical mechanical polishing pad according to the embodiment can be used for a wide range of chemical mechanical polishing processes, and can be particularly preferably used for a damascene wiring forming process using copper as a wiring material. . The process of forming damascene wiring using copper as the wiring material consists of depositing copper as the wiring material after forming the barrier metal layer in the groove portion of the insulating film in which the groove is to be formed in the portion to be the wiring and in the portion other than the groove portion And removing the excess copper (first polishing process), removing the barrier metal outside the groove part (second polishing process), and slightly polishing the insulating film portion (third) A flat damascene wiring is obtained through a polishing process. The chemical mechanical polishing pad of the present invention can also be used in a chemical mechanical polishing step for use in any of the first to third polishing treatment steps.

  In addition, it should be understood that the above “copper” is an alloy of copper and aluminum, silicon, or the like other than pure copper, and includes a copper content of 95% by mass or more. .

3. Example and Comparative Example A chemical mechanical polishing pad according to an example of the present embodiment and a chemical mechanical polishing pad according to a comparative example were manufactured, and chemical mechanical polishing was performed. After polishing, the appearance of the chemical mechanical polishing pad was evaluated.

3.1. Production of chemical mechanical polishing pad (A) (Experiment 1)
1,2-polybutadiene (trade name “JSR RB830” manufactured by JSR Corporation) in 72.8 parts by mass and β-cyclodextrin (manufactured by Yokohama Kokusai Bio Laboratory Co., Ltd., trade name “Dexy Pearl β-100” 27.2 parts by mass of an average particle diameter of 20 μm) was kneaded for 2 minutes with a router adjusted to 160 ° C. Next, 0.55 parts by mass (dicumyl peroxide per 100 parts by mass of 1,2-polybutadiene) “Park Mill D40” (trade name, manufactured by NOF Corporation, containing 40% by mass of dicumyl peroxide) In terms of amount, it corresponds to 0.30 parts by mass.) Was further kneaded at 120 pm at 60 pm for 2 minutes to obtain chemical mechanical polishing pad composition pellets. A flat plate obtained by heating 1500 grams of the pellets at 170 ° C. for 18 minutes in a mold having a gap of 2.5 mm was obtained. Using a commercially available groove processing machine, concentric grooves having a pitch of 2.0 mm, a groove width of 0.5 mm, and a depth of 1.0 mm were formed to obtain a polishing layer.

  Furthermore, Sekisui Chemical Co., Ltd. double-sided tape, product name # 5673JX as the first adhesive layer is applied to the non-grooved side, followed by Nippon Kaijo Nipper Ray EXG (thickness 1.25 mm) as the cushion layer. Further, double-sided tape # 5673JX was attached as a second adhesive layer to obtain a chemical mechanical polishing pad (A-1). A chemical mechanical polishing pad (A-2) was obtained by removing the central part diameter 6 cm of the layer composed of the double-sided tape layer and the cushion layer of (A-1) in a circular shape.

3.2. Production of chemical mechanical polishing pads (B) and (C) (Experimental Examples 2 and 3)
Same as “3.1. Manufacture of chemical mechanical polishing pad (A)” except that the types and amounts used of each raw material in “3.1. Production of chemical mechanical polishing pad (A)” are as shown in Table 1. Was carried out. In Experimental Example 2, chemical mechanical polishing pads (B-1 to 2) were obtained, and in Experimental Example 3, chemical mechanical polishing pads (C-1 to 2) were obtained.

  However, the abbreviations used in Table 1 represent the following, respectively. Moreover, the numerical value in Table 1 is a mass part.

RB830: 1,2-polybutadiene (manufactured by JSR Corporation, trade name “JSR RB830”)
HF55: Polystyrene (manufactured by PS Japan Ltd., trade name “HF55”)
β-CD: β-cyclodextrin (manufactured by Yokohama International Bio-Institute, trade name “Dexy Pearl β-40”, average particle size 20 μm)
D40: Nippon Oil & Fat Co., Ltd., trade name “Park Mill D40”, containing 40% by mass of dicumyl peroxide.

  The chemical mechanical polishing pads (A-2), (B-2), and (C-2) have through holes, and the chemical mechanical polishing pads (A-1), (B-1), ( C-1) does not have a through hole.

３．３．化学機械研磨工程
３．１．および３．２．において製造した化学機械研摩パッドを、化学機械研磨装置「Ｒｅｆｌｅｘｉｏｎ―ＬＫ」（Ａｐｐｌｉｅｄ Ｍａｔｅｒｉａｌｓ社製）の定盤上に装着し、Ｐ−ＴＥＯＳブランケットウェハを化学機械研磨した。化学機械研磨の条件は以下のとおりである。

3.3. Chemical mechanical polishing process 3.1. And 3.2. The chemical mechanical polishing pad manufactured in 1 was mounted on a surface plate of a chemical mechanical polishing apparatus “Reflexion-LK” (manufactured by Applied Materials), and the P-TEOS blanket wafer was subjected to chemical mechanical polishing. The conditions for chemical mechanical polishing are as follows.

  Aqueous dispersion for chemical mechanical polishing: Silica abrasive-containing slurry manufactured by JSR Corporation, CMS-1101.

Aqueous dispersion supply amount: 300 mL / min Plate rotation speed: 63 rpm
Head rotation speed: 60rpm
Head pressing pressure Retainer ring pressure: 8 psi
Membrane pressure: 4.0 psi
Polishing time: 60 seconds 3.4. Evaluation The appearance of the chemical mechanical polishing pad after chemical mechanical polishing was evaluated. The evaluation results are shown in Table 2.

表２に示すように、化学機械研磨パッド（Ａ−２）、（Ｂ−２）、（Ｃ−２）については、３００枚で検討を終えたが溝は全くダメージを受けていなかった。これらの結果から、パッド裏面中央部のクッション層に貫通孔を形成することにより、研磨ヘッドからかかる過負荷を緩和し、過負荷によって溝へ与えるダメージを防ぐことができたことが認められた。以上のことから本発明によって、研磨層のダメージを抑制することができ、製品寿命が長い化学機械研磨パッドが提供されることが可能になった。

As shown in Table 2, with regard to the chemical mechanical polishing pads (A-2), (B-2), and (C-2), the study was completed with 300 sheets, but the grooves were not damaged at all. From these results, it was confirmed that by forming a through hole in the cushion layer at the center of the back surface of the pad, the overload applied from the polishing head was alleviated and damage to the groove due to the overload could be prevented. From the above, according to the present invention, it is possible to provide a chemical mechanical polishing pad that can suppress damage to the polishing layer and has a long product life.

  This completes the description of the present embodiment. The present invention is not limited to the above-described embodiment, and various modifications can be made. For example, the first adhesive layer and the second adhesive layer may not be provided. In that case, for example, the cushion layer and the polishing layer can be fixed to the polishing apparatus surface plate by heating the surface of the cushion layer and fusing it to the polishing layer or the polishing apparatus surface plate.

  Further, the invention includes substantially the same configuration (for example, a configuration having the same function, method, and result, or a configuration having the same purpose and result) as the configuration described in the embodiment. In addition, the invention includes a configuration in which a non-essential part of the configuration described in the embodiment is replaced. In addition, the present invention includes a configuration that exhibits the same operational effects as the configuration described in the embodiment or a configuration that can achieve the same object. Further, the invention includes a configuration in which a known technique is added to the configuration described in the embodiment.

It is sectional drawing which shows the chemical mechanical polishing pad which concerns on this Embodiment. It is a figure for demonstrating the chemical mechanical polishing method which concerns on this Embodiment. It is a figure for demonstrating the chemical mechanical polishing method which concerns on this Embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Chemical mechanical polishing pad, 11 ... Polishing layer, 12 ... 1st contact bonding layer, 13 ... Polishing apparatus surface plate, 14 ... Cushion layer, 15 ... 2nd contact bonding layer, 20, 22, 24 ... Through-hole, 30 ... Semiconductor wafer, 32 ... Holder

Claims (4)

A chemical mechanical polishing pad for fixing to a polishing apparatus surface plate,
A polishing layer;
Having a cushion layer provided between the polishing layer and the polishing apparatus surface plate,
The cushion layer is a chemical mechanical polishing pad having a through hole in a region including a central portion of the polishing layer. A chemical mechanical polishing pad for fixing to a polishing apparatus surface plate,
A polishing layer;
A first adhesive layer, a cushion layer, and a second adhesive layer, which are provided between the polishing layer and the polishing apparatus surface plate and provided in order from the polishing layer side;
The first adhesive layer adheres the polishing layer to the cushion layer,
The second adhesive layer adheres the cushion layer to the polishing apparatus surface plate,
The cushion layer is thicker than the first adhesive layer and the second adhesive layer,
Each of the first adhesive layer, the cushion layer, and the second adhesive layer is a chemical mechanical polishing pad having a through hole in a region including a central portion of the polishing layer.   The chemical mechanical polishing pad according to claim 1, wherein the through hole has a circular shape.   A chemical mechanical polishing method using the chemical mechanical polishing pad according to claim 1.

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