JP4645825B2 - Chemical mechanical polishing pad and chemical mechanical polishing method - Google Patents

Description

  The present invention relates to a chemical mechanical polishing pad that can be suitably used in a chemical mechanical polishing step, and a chemical mechanical polishing method using the polishing pad.

In the manufacture of semiconductor devices, chemical mechanical polishing (“CMP”) has attracted attention as a polishing method capable of forming a surface having excellent flatness. Chemical mechanical polishing is a technique in which a chemical mechanical polishing aqueous dispersion, such as an aqueous dispersion in which abrasive grains are dispersed, flows down on the surface of a chemical mechanical polishing pad while sliding the polishing pad and the surface to be polished. It is. In this chemical mechanical polishing, it is known that the polishing result greatly depends on the properties and characteristics of the polishing pad.
Conventionally, in the chemical mechanical polishing, a polyurethane foam containing fine bubbles is used as a polishing pad, and polishing is performed by holding a slurry in a hole (hereinafter referred to as “pore”) opened on the surface of the resin. At this time, it is known that a polishing rate and a polishing result are improved by providing a groove on the surface (polishing surface) of the chemical mechanical polishing pad (see Patent Document 1, Patent Document 2, and Patent Document 3).
However, in recent years, along with the high performance and miniaturization of semiconductor devices, the miniaturization and multi-layering of wiring have progressed, and the required performance for chemical mechanical polishing and chemical mechanical polishing pads has increased. In the above-mentioned Patent Document 1, the design of the chemical polishing pad is described in detail, but the polishing rate and the state of the polished surface after polishing are not yet satisfactory. In particular, scratch-like surface defects (hereinafter referred to as “scratch”) may occur, and improvements are desired.
JP-A-11-70463 JP-A-8-216029 JP-A-8-39423

The present invention solves the above-mentioned conventional problems, and an object of the present invention is to provide a chemical mechanical polishing pad and a polishing pad that are sufficiently suppressed in the generation of scratches on the surface to be polished and excellent in polishing rate. It is to provide a chemical mechanical polishing method used.
Still other objects and advantages of the present invention will become apparent from the following description.

According to the present invention, the above objects and advantages of the present invention are as follows.
A polishing surface, a non-polishing surface facing the polishing surface, and a side surface defining these surfaces, the polishing surface having at least two groove groups each consisting of a plurality of grooves, wherein the two groove groups are (i) A first groove group consisting of a plurality of first grooves intersecting with one virtual straight line from the center to the periphery of the polishing surface, and the plurality of first grooves are arranged concentrically so as not to cross each other. And (ii) a plurality of second grooves extending in a direction from the center portion to the peripheral portion of the polishing surface and intersecting the first grooves of the first groove group. the second groove group consisting, second grooves between the plurality book is rather Na which intersect each other, and a plurality of linear grooves toward the peripheral portion originating from the central portion, originating from the middle between the center portion and the peripheral portion Consists of a plurality of linear grooves toward the periphery ,
Consist of,
Chemical mechanical polishing pad, characterized in that (hereinafter, sometimes referred to Migaku Ken pad of the present invention) is accomplished by.

According to the present invention, the above objects and advantages of the present invention, the second,
The chemical mechanical polishing pad of the present invention is used to achieve the chemical mechanical polishing method.

  The chemical mechanical polishing pad of the present invention is sufficiently suppressed in the generation of scratches on the surface to be polished and has an excellent polishing rate. The chemical mechanical polishing method of the present invention using the polishing pad has a high polishing rate. It provides an object to be polished having an excellent surface state.

Hereinafter, the present invention will be described in detail .

Shape of the first groove of the first groove group on the polished surface, are multiple the rings or polygons der to and concentrically arranged without intersecting the each other physician. The annular groove can be, for example, a circle, an ellipse, or the like, and the polygonal groove can be, for example, a quadrilateral, a pentagon or more polygon.
The plurality of first grooves in the first groove group do not intersect each other.
These first grooves are provided on the polishing surface so as to intersect a single virtual straight line from the center of the polishing surface to the peripheral portion a plurality of times. For example, when the groove shape is composed of the plurality of rings described above, two rings have two intersections, three rings have three, and n rings have n .

The case of a plurality of polygons is the same as the case of a plurality of rings.
When composed of a plurality of rings or polygons, although multiple rings or polygons are arranged so as not to intersect with each other, the arrangement Ru concentric der. The polishing pad arranged concentrically is superior to the above in comparison with other polishing pads. Arbitrariness preferred that a plurality of ring is composed of a plurality of circular ring. In addition, since the annular grooves are concentric, these functions are further improved, and the grooves can be easily produced.
Moreover, the cross-sectional shape in the direction perpendicular to the width direction of the groove, that is, the groove direction is not particularly limited. For example, it may be a polyhedral shape of three or more surfaces formed by flat side surfaces and a bottom surface, a U shape, a V shape, or the like.

The number of the plurality of grooves (rings) having different diameters arranged concentrically can be, for example, 20 to 400, and the number of the plurality of spiral grooves can be, for example, 2 to 10. .
Although the magnitude | size of a groove | channel is not specifically limited, For example, the groove width of a 1st groove | channel can be 0.1 mm or more, Preferably it is 0.1-5 mm, More preferably, it can be 0.2-3 mm. . Moreover, the depth of a groove | channel can be 0.1 mm or more, Preferably it is 0.1-2.5 mm, More preferably, it can be 0.2-2.0 mm. Furthermore, the groove interval can be 0.05 mm or more, preferably 0.05 to 100 mm, and the smallest of the distances between adjacent intersections of the virtual straight line and the plurality of first grooves is preferably 0.05 to 100 mm. Preferably it can be 0.1-10 mm. By setting the grooves within these ranges, it is possible to easily manufacture a chemical mechanical polishing pad having an excellent effect of reducing scratches on the surface to be polished and having a long life.

  Each of the above preferred ranges can be a combination of each. For example, the groove width can be 0.1 mm or more, the groove depth can be 0.1 mm or more, and the groove interval can be 0.05 mm or more, preferably the groove width is 0.1 to 5 mm. The groove width can be 0.15 to 105 mm, the groove width is preferably 0.2 to 3 mm, and the groove depth is 0.2 to 2.mm. 0 mm, and the groove interval can be 0.6 to 13 mm.

The cross-sectional shape of the groove, that is, the shape of the cut surface when the groove is cut in the normal direction thereof is not particularly limited, and may be, for example, a polygonal shape or a U-shape. Examples of the polygon include a triangle, a quadrangle, and a pentagon.
Moreover, it is preferable that the pitch which is the sum of the width | variety of a groove | channel and the distance between adjacent grooves is 0.15 mm or more, More preferably, it is 0.15-105 mm, More preferably, it is 0.5-13 mm. Yes, particularly preferably 0.5 to 5.0 mm, especially 0.5 to 2.2 mm.
Further, the surface roughness (Ra) of the inner surface of the first groove is preferably 20 μm or less, more preferably 0.05 to 15 μm, and still more preferably 0.05 to 10 μm. By setting the surface roughness to 20 μm or less, scratches generated on the surface to be polished during the chemical mechanical polishing step can be more effectively prevented.

The surface roughness (Ra) is defined by the following formula (1).
Ra = Σ | Z−Z _av | / N (1)
However, in the above formula, N is the number of measurement points, Z is the height of the roughness phase, and Z _av is the average height of the roughness phase.
The second groove of the second groove group includes a plurality of grooves extending in a direction from the center portion to the peripheral portion of the polishing surface, and a plurality of linear grooves extending from the middle of the center portion and the peripheral portion toward the peripheral portion. Consists of. Here, the center portion refers to a region surrounded by a circle with a radius of 50 mm centered on the center of gravity on the chemical mechanical polishing pad surface. Each second groove belonging to the second groove group has only to extend in a direction toward the peripheral portion from any one point of the "center", the shape, Ru Oh straight linear.

The second groove may or may not reach the outer peripheral end, but at least one of the grooves preferably reaches the outer peripheral end, that is, the side surface of the pad. For example, the second groove of the plurality of is composed of a plurality of linear grooves toward the peripheral portion originating from the centered portion, a plurality of linear grooves toward the peripheral portion emitted from the middle of the central portion and the peripheral portion And at least one of the grooves can reach the side surface of the pad. Further, the plurality of second grooves can be composed of a pair of two parallel linear grooves.
The number of second grooves in the second groove group is preferably 4 to 65, and more preferably 8 to 48.

The second grooves belonging to the second groove group existing on the chemical mechanical polishing pad surface may or may not be in contact with other grooves belonging to the second groove group, but intersect each other. There is no. It is preferable that 2 to 32 of the plurality of second grooves are in contact with other second grooves in the central region, and that 2 to 16 are in contact with other second grooves. preferable. The second groove may be in contact with another groove and the second groove at a place other than the center portion of the pad surface.
The preferred groove width and depth of the second groove are the same as the width and depth of the first groove. The preferable range of the surface roughness (Ra) of the inner surface of the second groove is the same as the preferable range of the surface roughness (Ra) of the inner surface of the first groove.
The plurality of second grooves in the second groove group are preferably arranged as evenly as possible on the chemical mechanical polishing pad surface.
The second groove group formed in the polishing surface of the chemical mechanical polishing pad of the present invention may be, for example, configured as schematically shown in FIGS. 2, 3, 8 and 9.

Next, the configuration of the groove of the chemical mechanical polishing pad according to the present invention will be described with reference to the accompanying drawings .

The pad shown in FIG. 2 has a second groove group composed of 32 straight grooves 2 and a first groove group composed of ten concentric grooves 3 having different diameters. Of the 32 straight grooves, 4 start from the center, while the other 28 straight grooves are parts that have receded somewhat from the center to the periphery (this part is the first The smallest circular groove in the groove group can be determined by the fact that this straight groove intersects). In the pad 2, 32 of the linear grooves has reached the side surface of all pads.

  In FIG. 3, the pad 1 has a second groove group composed of 64 straight grooves 2 and a first groove group composed of ten circular circular grooves 3 having different diameters. Eight of the 64 straight grooves start from the center, while the remaining 56 straight grooves start from a portion that is somewhat receded from the center to the periphery. In the pad of FIG. 3, all 64 linear grooves reach the side surface of the pad.

  The pad shown in FIG. 8 corresponds to a pad having 32 straight grooves extending from midway between the central portion and the peripheral portion between all of the 32 straight grooves in FIG. The 32 straight grooves start from a point intersecting the fourth concentric groove from the center in the figure.

  The pad shown in FIG. 9 corresponds to a pad that forms a pair of 28 linear grooves, each of which is formed by retreating from the center somewhat back to the periphery in FIG.

The groove arrangement on the polishing surface of the polishing pad of the present invention, as understood from FIGS. 2, 3, 8 and 9 above, exhibits symmetry, eg, point symmetry, line symmetry or plane symmetry with respect to the center. Preferably, it is performed.

Upper Symbol Migaku Ken pad of the present invention may have a recess as necessary to the non-polishing surface side (back surface of the pad). The concave portion has a function of dispersing a local pressure increase due to pressurization of the polishing head during the chemical mechanical polishing step, and contributes to further reduction of scratches on the surface to be polished. The position of the recess is not particularly limited, but is preferably located at the center of the pad. Here, “located in the central portion” is not limited to the case where it is positioned at the center in a mathematically strict sense, but it is sufficient that the center of the non-polishing surface of the polishing pad is positioned within the range of the recess.
Although the shape of a recessed part is not specifically limited, It is preferable that it is circular or polygonal shape, and circular is especially preferable. When the shape of the concave portion is circular, the upper limit value of the diameter is preferably 100%, more preferably 75%, and particularly preferably 50% of the diameter of the wafer as the object to be polished. When the shape of the recess is circular, the lower limit of the diameter is preferably 1 mm, more preferably 5 mm, regardless of the size of the wafer that is the object to be polished.

The shape of the chemical mechanical polishing pad of the present invention is not particularly limited, but can be, for example, a disc shape, a polygonal column shape, etc., and can be appropriately selected according to the polishing apparatus to which the chemical mechanical polishing pad of the present invention is attached and used. Can do.
For example, when it has a disk-shaped outer shape, the opposing circular upper surface and circular lower surface become a polished surface and a non-polished surface, respectively.
The size of the chemical mechanical polishing pad is also not particularly limited. For example, in the case of a disc-shaped chemical mechanical polishing pad, the diameter is 150 to 1200 mm, particularly 500 to 800 mm, the thickness is 0.5 to 5.0 mm, and particularly the thickness is 1.0 to 1.0. The thickness can be set to 3.0 mm, especially 1.5 to 3.0 mm.

The chemical mechanical polishing pad of the present invention may be composed of any material as long as it has the grooves as described above. For example, a water-insoluble matrix material and dispersed in the water-insoluble matrix material It can be one containing water-soluble particles or a pad having fine bubbles in a water-insoluble matrix.
Among these, the former material contacts the aqueous medium of the slurry containing the aqueous medium and the solid content during the polishing, dissolves or swells and desorbs, and the slurry is formed in the pores formed by the desorption. Can be held. On the other hand, the latter material can hold the slurry in a pore that is formed in advance as a cavity.

The material constituting the “water-insoluble matrix” is not particularly limited. However, an organic material is preferably used because it can be easily molded into a predetermined shape and properties, and can provide appropriate hardness, appropriate elasticity, and the like. It is done. As the organic material, for example, a thermoplastic resin, an elastomer, a rubber such as a crosslinked rubber, and a cured resin such as a thermosetting resin or a photocurable resin, a resin cured by heat, light, or the like can be used alone or in combination. .
Among these, examples of the thermoplastic resin include 1,2-polybutadiene resin, polyolefin resin such as polyethylene, polystyrene resin, polyacrylic resin such as (meth) acrylate resin, vinyl ester resin (excluding acrylic resin), and polyester resin. Fluorine resin such as polyamide resin and polyvinylidene fluoride, polycarbonate resin, polyacetal resin and the like.

  Examples of the elastomer include a diene elastomer such as 1,2-polybutadiene, a polyolefin elastomer (TPO), a styrene-butadiene-styrene block copolymer (SBS), a styrene elastomer such as a hydrogenated block copolymer (SEBS), Examples thereof include thermoplastic elastomers such as thermoplastic polyurethane elastomer (TPU), thermoplastic polyester elastomer (TPEE), polyamide elastomer (TPAE), silicone resin elastomer, and fluororesin elastomer. Examples of the rubber include butadiene rubber (high cis butadiene rubber, low cis butadiene rubber, etc.), isoprene rubber, styrene-butadiene rubber, conjugated diene rubber such as styrene-isoprene rubber, nitrile rubber such as acrylonitrile-butadiene rubber, and acrylic rubber. And ethylene-α-olefin rubber such as ethylene-propylene rubber and ethylene-propylene-diene rubber, and butyl rubber, and other rubbers such as silicone rubber and fluororubber.

Examples of the cured resin include urethane resin, epoxy resin, acrylic resin, unsaturated polyester resin, polyurethane-urea resin, urea resin, silicon resin, phenol resin, and vinyl ester resin.
These organic materials may be modified with an acid anhydride group, a carboxyl group, a hydroxyl group, an epoxy group, an amino group, or the like. By modification, the affinity with water-soluble particles and slurry described later can be adjusted.
These organic materials may use only 1 type and may use 2 or more types together.

  These organic materials may be a crosslinked polymer partially or wholly crosslinked or a non-crosslinked polymer. Therefore, the water-insoluble matrix may be composed of only a crosslinked polymer, a mixture of a crosslinked polymer and a non-crosslinked polymer, or may be composed of only a non-crosslinked polymer. However, it is preferable to consist only of a crosslinked polymer or a mixture of a crosslinked polymer and a non-crosslinked polymer. By containing the cross-linked polymer, an elastic recovery force is imparted to the water-insoluble matrix, and displacement due to shear stress applied to the polishing pad during polishing can be suppressed to a small level. Further, it is possible to effectively suppress the water-insoluble matrix from being excessively stretched during plasticizing and dressing to be plastically deformed to fill the pores, and the polishing pad surface from becoming excessively fuzzy. Accordingly, pores can be efficiently formed even during dressing, and a decrease in the retention of the slurry during polishing can be prevented, and further, there is little fuzzing and polishing flatness is not hindered. The method for performing the crosslinking is not particularly limited. For example, the crosslinking can be performed by chemical crosslinking using an organic peroxide, sulfur, a sulfur compound, or the like, or radiation crosslinking by electron beam irradiation.

  Of these, the chemical crosslinking method is preferred. When the cross-linking is chemical cross-linking, it is preferable to use an organic peroxide as the cross-linking agent from the viewpoints of good handleability and no contamination to the object to be polished. Examples of the organic peroxide include dicumyl peroxide, diethyl peroxide, di-t-butyl peroxide, diacetyl during peroxidation, diacyl peroxide and the like. When the crosslinking is performed by a chemical crosslinking method, the amount of the crosslinking agent used is preferably 0.01 to 5.0 parts by mass, more preferably 100 parts by mass of the crosslinking polymer in the water-insoluble member. Is 0.2 to 4.0 parts by mass. By setting the amount used within this range, it is possible to obtain a chemical mechanical polishing pad in which the generation of scratches is suppressed in the chemical mechanical polishing step. Crosslinking may be performed collectively for all of the materials constituting the water-insoluble member, or may be mixed with the remainder after crosslinking is performed on a portion of the material constituting the water-insoluble member. Moreover, you may mix several types of crosslinked material which performed special bridge | crosslinking.

When cross-linking is based on a chemical cross-linking method, by adjusting the amount of cross-linking agent used and cross-linking conditions, a part of the water-insoluble member is cross-linked and the other part is not cross-linked by a single cross-linking operation. A mixture of organic materials can be easily obtained. Further, when the crosslinking is performed by a radiation crosslinking method, the same effect as described above can be easily obtained by adjusting the radiation dose.
As the crosslinked polymer, among the above organic materials, a crosslinked rubber, a cured resin, a crosslinked thermoplastic resin, a crosslinked elastomer, and the like can be used. Furthermore, among these, a crosslinked thermoplastic resin and / or a crosslinked elastomer is preferable because it is stable against strong acids and strong alkalis contained in many slurries and is less softened by water absorption. Of the crosslinked thermoplastic resins and crosslinked elastomers, those crosslinked with an organic peroxide are particularly preferred, and crosslinked 1,2-polybutadiene is more preferred.

  The content of these cross-linked polymers is not particularly limited, but is preferably 30% by volume or more, more preferably 50% by volume or more, still more preferably 70% by volume or more and 100% by volume of the entire water-insoluble matrix. Also good. If the content of the crosslinked polymer in the water-insoluble matrix is less than 30% by volume, the effect of sufficiently containing the crosslinked polymer may not be exhibited.

  The water-insoluble matrix containing a cross-linked polymer is an elongation remaining after fracture (hereinafter simply referred to as “breaking residual elongation”) when a test piece made of a water-insoluble matrix is broken at 80 ° C. in accordance with JIS K 6251. May be 100% or less. That is, the total distance between the marked lines after the fracture is not more than twice the distance between the marked lines before the fracture. The residual elongation at break is preferably 30% or less, more preferably 10% or less, and particularly preferably 5% or less. If the residual elongation at break exceeds 100%, fine pieces scraped or stretched from the surface of the polishing pad during polishing and surface renewal tend to easily block the pores, which is not preferable. This “residual elongation at break” is a test piece in a tensile test at a test piece shape dumbbell shape No. 3, tensile speed 500 mm / min, test temperature 80 ° C. according to JIS K 6251 “Tensile test method for vulcanized rubber”. Is the elongation obtained by subtracting the distance between the marked lines before the test from the total distance from the marked line to the broken part of each of the test pieces divided by breaking. In actual polishing, since heat is generated by sliding, the test is performed at a temperature of 80 ° C.

The “water-soluble particles” are particles that are detached from the water-insoluble matrix by contacting with the slurry that is an aqueous dispersion in the polishing pad. This desorption may be caused by dissolution by contact with water or the like contained in the slurry, or may be caused by swelling and gelation containing this water or the like. Furthermore, this dissolution or swelling is not only caused by water, but may also be caused by contact with an aqueous mixed medium containing an alcohol solvent such as methanol.
In addition to the effect of forming pores, the water-soluble particles have an effect of increasing the indentation hardness of the polishing pad in the polishing pad. For example, by containing water-soluble particles, the Shore D hardness of the polishing pad of the present invention can be preferably 35 or more, more preferably 50 to 90, still more preferably 50 to 80, and usually 100 or less. When the Shore D hardness exceeds 35, the pressure that can be applied to the object to be polished can be increased, and the polishing rate can be improved accordingly. In addition, high polishing flatness can be obtained. Therefore, it is particularly preferable that the water-soluble particles are solid bodies that can ensure sufficient indentation hardness in the polishing pad.

  The material constituting the water-soluble particles is not particularly limited, and examples thereof include organic water-soluble particles and inorganic water-soluble particles. Examples of the material for the organic water-soluble particles include saccharides such as starch, polysaccharides such as dextrin and cyclodextrin, lactose and mannitol, celluloses such as hydroxypropylcellulose and methylcellulose, proteins, polyvinyl alcohol, polyvinylpyrrolidone, poly Examples thereof include acrylic acid, polyethylene oxide, water-soluble photosensitive resin, sulfonated polyisoprene, and sulfonated polyisoprene copolymer. Furthermore, examples of the material for the inorganic water-soluble particles include potassium acetate, potassium nitrate, potassium carbonate, potassium hydrogen carbonate, potassium chloride, potassium bromide, potassium phosphate, and magnesium nitrate. These water-soluble particles may be used alone or in combination of two or more. Furthermore, 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.

  The average particle size of the water-soluble particles is preferably 0.1 to 500 μm, more preferably 0.5 to 100 μm. The size of the pore is preferably 0.1 to 500 μm, more preferably 0.5 to 100 μm. If the average particle size of the water-soluble particles is less than 0.1 μm, the size of the pores formed is smaller than the abrasive grains used, so that it is difficult to obtain a polishing pad that can sufficiently hold the slurry. On the other hand, when the thickness exceeds 500 μm, the mechanical strength and polishing rate of the polishing pad that can be obtained are excessively large and the polishing rate tends to decrease.

  The content of the water-soluble particles is preferably 2 to 90% by volume, more preferably 2 to 60% by volume when the total of the water-insoluble matrix and the water-soluble particles is 100% by volume. More preferably, it is 2 to 40% by volume. When the content of the water-soluble particles is less than 2% by volume, pores are not sufficiently formed in the resulting polishing pad, and the polishing rate tends to decrease. On the other hand, when it contains water-soluble particles in excess of 90% by volume, it tends to be difficult to sufficiently prevent the water-soluble particles present inside the polishing pad from swelling or dissolving in the resulting polishing pad. It becomes difficult to maintain the hardness and mechanical strength of the resin at appropriate values.

  Further, it is preferable that the water-soluble particles dissolve in water only when exposed to the surface layer in the polishing pad, absorb moisture inside the polishing pad, and do not swell further. For this reason, water-soluble particle | grains can be equipped with the outer shell which suppresses moisture absorption in at least one part of outermost part. The outer shell may be physically adsorbed on the water-soluble particles, may be chemically bonded to the water-soluble particles, or may be in contact with 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. Even if the outer shell is formed only on a part of the water-soluble particles, the above effect can be sufficiently obtained.

  The water-insoluble matrix can contain a compatibilizing agent in order to control the affinity with the water-soluble particles and the dispersibility of the water-soluble particles in the water-insoluble matrix. Examples of the compatibilizer include polymers modified with acid anhydride groups, carboxyl groups, hydroxyl groups, epoxy groups, oxazoline groups, amino groups, block copolymers, random copolymers, and various nonions. Examples thereof include system surfactants and coupling agents.

On the other hand, examples of the water-insoluble matrix material constituting the polishing pad comprising a water-insoluble matrix material (such as foam) formed by dispersing the latter cavities include, for example, polyurethane, melamine resin, polyester, polysulfone, and polyvinyl acetate. Etc.
The size of the cavities dispersed in such a water-insoluble matrix material is an average value, preferably 0.1 to 500 μm, more preferably 0.5 to 100 μm.

  The method for producing the chemical mechanical polishing pad of the present invention is not particularly limited, and a groove of the chemical mechanical polishing pad and a concave portion on the back surface optionally included (hereinafter, both are collectively referred to as “grooves”). The forming method is not particularly limited. For example, a chemical mechanical polishing pad composition to be a chemical mechanical polishing pad is prepared in advance, and the composition is formed into a desired shape, and then a groove or the like can be formed by cutting. Further, by molding a chemical mechanical polishing pad composition using a mold in which a pattern to be a groove or the like is formed, a groove or the like can be formed simultaneously with the outline of the chemical mechanical polishing pad. Here, according to the mold forming, the surface roughness of the inner surface of the groove can be easily reduced to 20 μm or less.

  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 kneader 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 a polishing pad 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.
The chemical mechanical polishing pad of the present invention may be a multilayer pad having a support layer on the non-polishing surface of the pad as described above.

  The support layer is a layer that supports the chemical mechanical polishing pad on the back surface of the polishing surface. The characteristics of the support layer are not particularly limited, but are preferably softer than the pad body. By providing a softer support layer, it is possible to prevent the pad body from floating during polishing and the surface of the polishing layer from being curved even when the pad body is thin, for example, 1.0 mm or less. Polishing can be performed stably. The hardness of the support layer is preferably 90% or less of the hardness of the pad body, more preferably 50 to 90%, particularly preferably 50 to 80%, and particularly preferably 50 to 70%.

The support layer may be a porous body such as a foam or a non-porous body. Furthermore, the planar shape is not particularly limited, and may be the same as or different from the polishing layer. The planar shape of the support layer can be, for example, a circle, a polygon, such as a quadrangle, and the like. Moreover, although the thickness is not specifically limited, for example, 0.1-5 mm is preferable, More preferably, it can be 0.5-2 mm.
The material constituting the support layer is not particularly limited, but it is preferable to use an organic material because it can be easily molded into a predetermined shape and properties and can be provided with appropriate elasticity.

The chemical mechanical polishing pad of the present invention as described above can obtain a good polished surface at a high polishing rate and has a long life.
The chemical mechanical polishing pad of the present invention is not yet clear about the mechanism for reducing scratches generated on the polishing surface of the object to be polished. However, in the conventionally known chemical mechanical polishing pad, the chemical mechanical polishing step At this time, since a phenomenon in which the chemical mechanical polishing aqueous dispersion, polishing scraps, and the like stay in the central portion of the pad was observed, it is presumed that the stayed material worked as a scratch generation source. On the other hand, when the chemical mechanical polishing pad of the present invention is used, the above retention phenomenon is not observed during the chemical mechanical polishing process. Therefore, the retention is effective by forming the groove as described above on the polishing surface. It is presumed that the effect of reducing scratches was exhibited.

The chemical mechanical polishing method of the present invention is characterized by using the chemical mechanical polishing pad of the present invention as described above. The chemical mechanical polishing pad of the present invention can be mounted on a commercially available polishing apparatus and used for chemical mechanical polishing by a known method.
The surface to be polished in that case and the type of chemical mechanical polishing aqueous dispersion to be used are not limited.

In the following, Examples 1, 6 and 8 are reference examples.
Example 1
(1) Manufacture of chemical mechanical polishing pad 80 parts by volume (corresponding to 72 parts by mass) of 1,2-polybutadiene (trade name “JSR RB830” manufactured by JSR Co., Ltd.) cross-linked to become a water-insoluble matrix, Β-cyclodextrin (product name “Dexipal β-100”, average particle size 20 μm) 20 parts by volume (corresponding to 28 parts by mass), which is a functional particle, was adjusted to 160 ° C. Kneaded with a prepared ruder. Thereafter, 1.0 part by volume (corresponding to 1.1 parts by mass) of dicumyl peroxide (Nippon Yushi Co., Ltd., trade name “Park Mill D”) was blended and further kneaded at 120 ° C. Obtained. Next, the kneaded product was heated in a mold at 170 ° C. for 18 minutes and crosslinked to obtain a disk-shaped molded body having a diameter of 600 mm and a thickness of 2.5 mm. Thereafter, a concentric groove having a width of 0.5 mm and a depth of 1.0 mm is formed on the polished surface side of the formed body using a cutting machine manufactured by Kato Machine Co., Ltd., and the pitch becomes 2.0 mm. (The grooves of the first groove group). Further, on the polishing surface side, 16 linear grooves (each width is 1.0 mm and depth is 1.0 mm) extending from the center of the pad to the outer peripheral edge at the center of the pad polishing surface. The angles formed between the adjacent linear grooves that are in contact with each other were 22.5 ° (grooves of the second groove group). The structure of the groove group formed here corresponds to the schematic diagram shown in FIG. When the surface roughness of the inner surface of the groove group formed here was measured with a three-dimensional surface structure analysis microscope (model “Zygo New View 5032”, manufactured by Canon Inc.), it was 4.2 μm.

(2) Evaluation of polishing speed and number of scratches The chemical mechanical polishing pad manufactured above is mounted on the surface plate of a polishing apparatus (manufactured by Ebara Manufacturing Co., Ltd., model “EPO112”), and is tripled as a slurry for chemical mechanical polishing. CMS-1101 (trade name, manufactured by JSR Co., Ltd.) diluted in the following is used, and a patternless SiO ₂ film (PETEOS film; tetraethylorthosilicate (TEOS) is used as a raw material under the following conditions, and plasma is used as an acceleration condition. Then, a wafer (a diameter of 8 inches) having a SiO ₂ film formed by chemical vapor deposition was polished, and the polishing rate and the number of scratches were evaluated. As a result, the polishing rate was 210 nm / min, and no scratch was observed on the polished surface.
Surface plate rotation speed: 70 rpm
Head rotation speed: 63 rpm
Head pressing pressure: 4 psi
Slurry supply amount: 200 mL / min Polishing time: 2 minutes In addition, the said polishing rate measured the film thickness before and behind polishing with the optical film thickness meter, and computed it from these film thickness differences. Also, the scratch was measured scratches total number generated on the entire surface of the polished surface by using a wafer defect inspection apparatus polished surface of the SiO ₂ film wafer after polishing (KLA-Tencor Corp., model "KLA2351") .

Example 2
In Example 1, four linear grooves (each having a width of 1.0 mm and a depth of 1.0 mm) extending from the center of the pad to the outer peripheral end as the grooves of the second groove group. The pads are formed in contact with each other at the center of the pad polishing surface so that the angle between the adjacent linear grooves is 90 °. Further, the linear grooves extending from the point 25 mm from the pad center to the outer peripheral edge are all adjacent straight lines. A chemical mechanical polishing pad was manufactured in the same manner as in Example 1 except that 28 linear grooves were formed so that the angle formed with the grooves was 11.25 °. The structure of the groove group formed here corresponds to the schematic diagram shown in FIG. The groove group formed here had an inner surface roughness of 3.9 μm.
The polishing rate and the number of scratches were evaluated in the same manner as in Example 1 except that the polishing pad prepared above was used. As a result, the polishing rate was 220 nm / min, and no scratch was observed.

Example 3
1,2-polybutadiene (manufactured by JSR Corporation, trade name “JSR RB830”) 64 parts by volume (corresponding to 58 parts by mass), 1,2-polybutadiene and polystyrene block polymer (manufactured by JSR Corporation, product) Name “TR2827”) 16 parts by volume (corresponding to 14 parts by mass k) and β-cyclodextrin which is water-soluble particles (manufactured by Yokohama International Bio-Industry Co., Ltd., trade name “Dexipal β-100”, average particle diameter 20 [mu] m) and 20 parts by volume (corresponding to 28 parts by mass) were kneaded by a router adjusted to 160 [deg.] C. Thereafter, 0.5 parts by volume (corresponding to 0.56 parts by mass) of dicumyl peroxide (Nippon Yushi Co., Ltd., trade name “Park Mill D”) was blended and further kneaded at 120 ° C. Obtained. Next, the kneaded product was heated in a mold at 180 ° C. for 10 minutes to be crosslinked to obtain a disk-shaped molded body having a diameter of 600 mm and a thickness of 2.5 mm. Thereafter, a concentric groove having a width of 0.5 mm and a depth of 1.0 mm is formed on the polishing surface side of the molded body using a cutting machine manufactured by Kato Machine Co., Ltd., and the pitch is 1.5 mm. It formed so that it might become (a groove of the 1st groove group). Further, eight linear grooves (each having a width of 1.0 mm and a depth of 1.0 mm) extending from the center of the pad to the outer peripheral edge are in contact with each other at the center of the pad polishing surface and are adjacent to each other. The angle formed with each straight groove is 45 °, and the angle formed between the linear groove extending from the point 25 mm from the pad center to the outer peripheral edge is 5.625 °. Thus, 56 linear grooves were formed (grooves of the second groove group). The structure of the groove group formed here corresponds to the schematic diagram shown in FIG. The groove group formed here had an inner surface roughness of 4.7 μm.
The polishing rate and the number of scratches were evaluated in the same manner as in Example 1 except that the polishing pad prepared above was used. As a result, the polishing rate was 185 nm / min, and no scratch was observed.

Example 4
1,2-polybutadiene (manufactured by JSR Corporation, trade name “JSR RB830”) 56 parts by volume (corresponding to 48 parts by mass) and polystyrene (A & Enstyrene Co., Ltd., trade name “GPPS HF55”) ) 14 parts by volume (corresponding to 12 parts by mass) and 30 parts by volume of β-cyclodextrin (trade name “Dexipal β-100”, average particle size 20 μm, manufactured by Yokohama International Bio-Laboratory Co., Ltd.) which is a water-soluble particle (Corresponding to 40 parts by mass) was kneaded with a router adjusted to 160 ° C. Thereafter, 0.5 parts by volume (corresponding to 0.56 parts by mass) of dicumyl peroxide (Nippon Yushi Co., Ltd., trade name “Park Mill D”) was blended and further kneaded at 120 ° C. Obtained. Next, the kneaded material was heated in a mold at 180 ° C. for 10 minutes to be crosslinked, thereby obtaining a disk-shaped molded body having a diameter of 600 mm and a thickness of 2.8 mm. Thereafter, a concentric groove having a width of 0.5 mm, a pitch of 2.0 mm, and a depth of 1.4 mm was formed on the polished surface side of the molded body using a cutting machine manufactured by Kato Machine Co., Ltd. (Grooves of the first groove group). Further, the grooves of the second groove group were formed in the same manner as the grooves of the second groove group in Example 2 except that the groove depth was 1.4 mm. The surface roughness of the inner surface of the groove group formed here was 3.5 μm.

Example 5
In Example 1, four linear grooves (each having a width of 1.0 mm and a depth of 1.0 mm) extending from the center of the pad to the outer peripheral portion as the grooves of the second groove group. The pads are formed in contact with each other at the center of the pad polishing surface so that the angle between the adjacent linear grooves is 90 °. Further, the linear grooves extending from the point 25 mm from the pad center to the outer peripheral edge are all adjacent straight lines. 28 grooves are formed so that the angle formed with the grooves is 11.25 °, and the angle between each of the linear grooves extending from the point 75 mm from the center of the pad to the outer peripheral edge with the adjacent linear grooves is A chemical mechanical polishing pad was produced in the same manner as in Example 1 except that 32 grooves were formed to be 5.625 °. The structure of the groove group manufactured here corresponds to the schematic diagram shown in FIG. In addition, the surface roughness of the inner surface of the groove group formed here was 4.0 μm.
When the polishing rate and the number of scratches were evaluated in the same manner as in Example 1 except that the polishing pad produced above was used, the polishing rate was 225 nm / min, and no scratch was observed.

Example 6
1,2-polybutadiene (manufactured by JSR Corporation, trade name “JSR RB830”) 80 parts by volume (corresponding to 72 parts by mass) and β-cyclodextrin which is water-soluble particles (manufactured by Yokohama International Bio-Laboratory Co., Ltd.) , 20 parts by volume (corresponding to 28 parts by mass) of a trade name “Dexipal β-100”, average particle size 20 μm) were kneaded by a rudder adjusted to 160 ° C. Thereafter, 0.12 part by volume (corresponding to 0.13 parts by mass) of dicumyl peroxide (Nippon Yushi Co., Ltd., trade name “Park Mill D”) was blended and further kneaded at 120 ° C. Obtained. Next, the kneaded product was heated in a mold at 170 ° C. for 18 minutes and crosslinked to obtain a disk-shaped molded body having a diameter of 800 mm and a thickness of 2.5 mm. Thereafter, a groove group similar to that in Example 1 was formed in this molded body. In the groove group formed here, the inner surface roughness of the groove group formed here was 3.5 μm. The central portion of this 800 mm diameter polishing pad was cut to a diameter of 600 mm, and the polishing rate and the number of scratches were evaluated in the same manner as in Example 1. As a result, the polishing rate was 254 nm / min, and no scratch was observed.

Example 7
In Example 2, a chemical mechanical polishing pad was manufactured in the same manner as in Example 2 except that each of the 28 linear grooves formed last was formed so as to be two linear grooves with an interval of 2 mm. The groove group formed here corresponds to the schematic diagram shown in FIG. The polishing rate and the number of scratches were evaluated in the same manner as in Example 1 except that the polishing pad produced here was used. As a result, the polishing rate was 233 nm / min, and no scratch was observed.
In addition, since the two linear grooves with a spacing of 2 mm are formed at the same spacing of 2 mm from the center of the pad toward the periphery, each of the two linear grooves originates from the center of the pad. It will be understood that it does not coincide with the diametric direction of the pad and is somewhat offset.

Example 8
28.2 parts by mass of polytetramethylene glycol having a number average molecular weight of 650 having two hydroxyl groups at both ends of the molecule (product name “PTMG650” manufactured by Mitsubishi Chemical Corporation) and 4,4′-diphenylmethane diisocyanate (Suika Bayer) 21.7 parts by mass of Urethane Co., Ltd., product name “Sumidur 44S”) was charged into a reaction vessel, stirred at 90 ° C. for 3 hours to be reacted, and then cooled to obtain a both-end isocyanate prepolymer. It was.

  Polypropylene glycol having a number average molecular weight of 330 having three hydroxyl groups as a crosslinking agent (Nippon Yushi Co., Ltd., product name “Uniol TG330”, addition reaction product of glycerin and propylene oxide) 21.6 parts by mass and polytetramethylene glycol 6.9 parts by mass of “PTMG650” is used, and β-cyclodextrin which is a water-soluble particle (product name “Dexipal β-100”, average particle diameter 20 μm, manufactured by Yokohama International Bio-Laboratory Co., Ltd.) 14.5 mass Then, 0.1 parts by mass of 2-methyltriethylenediamine (manufactured by Sankyo Air Products Co., Ltd., product name “Me-DABCO”) as a reaction accelerator was stirred and dissolved. This mixture was added to the reaction vessel of the both-end isocyanate prepolymer.

Further, 21.6 parts by mass of 4,4′-diphenylmethane diisocyanate “Sumijour 44S” was added to the reaction vessel of the above-mentioned both-end isocyanate prepolymer, stirred at 200 rpm for 2 minutes at room temperature, and further degassed under reduced pressure. A raw material mixture was obtained.
This raw material mixture is poured into a mold having a diameter of 60 cm and a thickness of 3 mm, held at 80 ° C. for 20 minutes to polymerize polyurethane, and further post-cured at 110 ° C. for 5 hours, a diameter of 600 mm and a thickness of 2.5 mm. A molded body of was obtained. Thereafter, a groove group similar to that in Example 1 was formed in this molded body. The groove group formed here had an inner surface roughness of 3.0 μm.
The polishing rate and the number of scratches were evaluated in the same manner as in Example 1 except that the polishing pad prepared above was used. As a result, the polishing rate was 231 nm / min, and no scratch was observed.

Comparative Example 1
In the same manner as in Example 1, a disk-shaped molded body having the same size was prepared, and using a commercially available cutting machine on the polishing surface side, the width was 0.5 mm, the pitch was 2.0 mm, and the depth was 1. A chemical mechanical polishing pad was produced in the same manner as in Example 1 except that only 0 mm concentric grooves (grooves of the first groove group) were formed. The groove group formed here had an inner surface roughness of 4.8 μm.
Using this polishing pad, the polishing rate and the presence or absence of scratches were evaluated in the same manner as in Example 1. As a result, the polishing rate was 200 nm / min, and there were 15 scratches.

Comparative Example 2
A disk-shaped molded body having the same size as that of Example 1 was prepared, and the concentric grooves of the first groove group were not formed on the polishing surface side, but only the grooves of the second groove group were formed. A polishing pad was produced according to Example 1. The surface roughness of the inner surface of the groove group formed here was 4.5 μm.
Using this polishing pad, the polishing rate and the presence or absence of scratches were evaluated in the same manner as in Example 1. As a result, the polishing rate was 120 nm / min, and there were 25 scratches.

Comparative Example 3
In the same manner as in Example 1, a disk-shaped molded body having the same size was prepared, and using a commercially available cutting machine on the polishing surface side, the width was 1.0 mm, the pitch was 10.0 mm, and the depth was 1. A chemical mechanical polishing pad was produced in the same manner as in Example 1 except that a 0 mm grid-like groove was formed. The groove group formed here had an inner surface roughness of 5.5 μm.
Using this polishing pad, the polishing rate and the presence or absence of scratches were evaluated in the same manner as in Example 1. As a result, the polishing rate was 150 nm / min, and there were 50 scratches.

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Claims (9)

A polishing surface, a non-polishing surface opposite to the polishing surface, and a side surface defining these surfaces, each of the polishing surfaces has at least two groove groups each including a plurality of grooves, and the two groove groups are ( i) A first groove group composed of a plurality of first grooves intersecting with one imaginary straight line extending from the center to the periphery of the polishing surface, and the plurality of first grooves do not intersect each other. It arranged concentrically, comprising a plurality of grooves having different diameters, and (ii) extends in the direction toward the periphery from the center of the polishing surface and the second grooves crossing the first grooves of the first groove group the second groove group consisting of a plurality of second grooves between the plurality book is rather Na which intersect each other, and a plurality of linear grooves toward the peripheral portion originating from the central portion, the central portion and the peripheral portion Consists of a plurality of linear grooves that start from the middle and go to the periphery ,
Consist of,
A chemical mechanical polishing pad characterized by that. The pad according to claim 1, which has a disk-like outer shape, and the opposed circular upper surface and circular lower surface are a polished surface and a non-polished surface, respectively. The pad according to claim 1 , wherein the number of grooves having a different diameter arranged concentrically is 20 to 400. The first groove has a groove width of 0.1 mm or more and a groove depth of 0.1 mm or more, and the minimum distance between adjacent intersections of the plurality of first grooves and the virtual line is 0.05 mm. The pad according to claim 1, which is as described above. The pad according to claim 1, wherein one of the plurality of second grooves reaches a side surface of the pad. The pad according to claim 1 , wherein the plurality of second grooves comprises a pair of two parallel linear grooves. The pad according to claim 1 , wherein the plurality of second grooves comprises 4 to 65 linear grooves. The pad according to claim 1 , wherein the second groove has a groove width of 0.1 mm or more and a groove depth of 0.1 mm or more. A chemical mechanical polishing method using the chemical mechanical polishing pad according to claim 1.

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