TWI822861B - Polishing pad and method of manufacturing same - Google Patents

Abstract

The present invention aims to provide a polishing pad that shortens the time required for running-in and reduces defects in the early stage of polishing. A polishing pad having a polishing layer for polishing an object to be polished, the polishing pad being characterized by an average arithmetic mean height (Sa ) is 3 to 10 (μm), and the average of the main curvatures of the peak apex of the polishing surface, that is, the arithmetic mean curvature (Spc) of the peak apex, is 200 to 600 (1/mm).

Description

Polishing pad and method of manufacturing same

The present invention relates to a polishing pad. Specifically, the present invention relates to a polishing method that can be used for polishing optical materials, semiconductor wafers, semiconductor devices, hard disk substrates, etc., and can be preferably used for polishing oxide layers formed on semiconductor wafers. A polishing pad for polishing devices such as , metal layers, etc.

As integration increases, semiconductor devices are becoming miniaturized or multi-layered. Therefore, in addition to productivity, polishing of glass substrates and the like used for semiconductor devices also requires removal of polishing scratches (suppression of defects and scratches) and the like.

As a grinding method that satisfies such requirements, grinding using a free abrasive grain method is generally used among various grinding methods. The free abrasive grain method is a method of polishing the processed surface of the object to be polished while supplying a slurry (polishing fluid) containing abrasive grains between the polishing pad and the object to be polished.

In free abrasive polishing, after the polishing pad is installed in the polishing device and before actual polishing is performed, the surface of the polishing pad (polishing surface) is generally polished by dressing using a diamond abrasive disc or the like. Roughening and sharpening. By performing polishing treatment, the polishing performance of the polishing pad can be improved. The so-called break in (activation). In order to improve the productivity of semiconductor wafers, it is desired to shorten the time required for the running-in.

Patent Document 1 discloses a polishing pad that can shorten the time required for running-in by setting the average surface roughness (Ra) of the polishing pad surface to 1 μm or more and 5 μm or less.

[Prior art documents]

[Patent Document]

[Patent Document 1] International Publication No. 2008/029725

However, it is known that if the average surface roughness (Ra) is simply adjusted, even if the time required for running-in can be shortened, defects may be large in the subsequent initial polishing period and the desired polishing performance may not be exhibited.

Therefore, the present invention aims to provide a polishing pad that shortens the time required for running-in and reduces defects in the early stage of polishing.

The present inventors conducted active research and found that by achieving polishing within a predetermined range, the arithmetic mean height (Sa) and the main curvature of the peak apex of the polishing layer surface, that is, the arithmetic mean curvature of the peak apex (Spc), can be achieved. Pads can shorten the running-in time and reduce defects, thus achieving the present invention. That is, the present invention includes the following contents.

[1] A polishing pad having a polishing layer for polishing an object to be polished, the polishing pad It is characterized in that the arithmetic mean height (Sa) representing the average absolute value of the difference in height of each point with respect to the average surface of the polishing surface of the polishing layer is 3 to 10 (μm), and the peak apex of the polishing surface is The average of the main curvature, that is, the arithmetic mean curvature (Spc) of the peak apex, is 200~600 (1/mm).

[2] The polishing pad according to [1], wherein the peak density (Spd) indicating the number of peak peaks per unit area of the polishing surface is 2000 to 6000 (1/mm ² ).

[3] A method of manufacturing a polishing pad, which is a method of manufacturing a polishing pad as described in [1] or [2], including setting the ratio of the paper circumferential speed to the platform speed (paper circumferential speed/platform speed) to be 50~ The step of polishing (buffing) is carried out under the conditions of 750°C.

The polishing pad of the present invention can shorten the running-in time and reduce defects in the early stage of polishing.

1: Polishing pad

2: Grinding layer

2a: grinding surface

3:Add layer

4: Buffer layer

5: Hollow tiny spheres

5a: Shell

5b: Internal space

6:Resin

Figure 1 is a perspective view of the polishing pad of the present invention.

Fig. 2 is a cross-sectional view of the polishing pad of the present invention.

3 is a cross-sectional view of the hollow microspheres included in the polishing pad of the present invention.

Figure 4 is a scanning electron microscope (SEM) photo of the polishing surface of the reference polishing pad.

FIG. 5 is an SEM photograph of the polishing surface of the polishing pad of Example 1.

FIG. 6 is an SEM photograph of the polishing surface of the polishing pad of Example 2.

FIG. 7 is an SEM photograph of the polishing surface of the polishing pad of Comparative Example 1.

Hereinafter, the embodiments for carrying out the invention will be described, but the present invention is not limited only to the embodiments for carrying out the invention.

In this specification, Ra represents the average of the absolute values of the differences in the heights of each point relative to the average line of the extracted portion when only the reference length l is extracted in the direction of the average line of the object surface, and is defined by Japanese Industrial Standards (Japanese Industrial Standards). Industrial Standard, JIS) B 671-1/ISO 13565-1 (line roughness measurement).

In this specification, Sa represents the average of the absolute values of the differences between the heights of each point when the reference area A is extracted with respect to the reference plane of the surface. In this specification, the unit of Sa is (μm).

In this specification, Spc represents the average of the principal curvatures of the peak apexes of the surface. That is, the average of the main curvatures of the peak apexes on the surface of the polishing layer is the arithmetic mean curvature of the peak apexes. In addition, when the value of Spc is small, it means that the point in contact with other objects is curved, and when the value of Spc is large, it means that the point in contact with other objects is sharp. In this manual, the unit of Spc is (1/mm).

In this specification, Spd represents the number of peak vertices per unit area. If this value is large, it means there are many contact points with other objects. In this specification, the unit is (1/mm ² ).

In addition, Sa, Spc, and Spd are all regulated by the International Organization for Standardization (ISO) 25178 (Three-dimensional surface properties (surface roughness)).

<<Polishing pad>>

The polishing pad of the present invention will be described.

Usually, even if a polishing pad is polished for the first time after manufacturing and is used for polishing without surface treatment of the polishing surface, the polishing rate is insufficient, and it is difficult to say that the polishing pad can be polished appropriately. Therefore, the polishing process and preliminary polishing are repeated in the initial stage of polishing, and after a sufficient polishing rate is achieved, the actual product is polished.

However, in the polishing pad of the present invention, polishing can be performed at a sufficient polishing rate even if no polishing process is performed at all or if the polishing process is shorter than the usual polishing process time.

The structure of the polishing pad of the present invention will be described using FIGS. 1 to 3 . As shown in FIG. 1 , the polishing pad 1 includes a polishing layer 2 that is in contact with an object to be polished and polished. The polishing layer 2 has a polishing surface 2a which is in contact with the object to be polished. The shape of the polishing layer 2 of the polishing pad 1 of the present invention is not particularly limited. Examples of the shape include disc shape, belt shape, etc., with disc shape being preferred.

The size (diameter) of the polishing pad 1 can be determined according to the size of the polishing device equipped with the polishing pad 1, and can be, for example, about 10 cm to 1 m in diameter.

The thickness of the grinding layer 2 is preferably 0.1mm~10mm, more preferably 0.3mm~5mm.

In addition, the polishing pad of the present invention may also include only a polishing layer.

In the polishing pad 1 , it is preferable that the polishing layer 2 is adhered to the cushion layer 4 via the adhesive layer 3 . The adhesive layer 3 is a layer used to connect the polishing layer 2 and the buffer layer 4, and usually includes an adhesive tape or an adhesive material.

The buffer layer 4 is a layer that makes the contact of the polishing layer 2 with the object to be polished more uniform. The buffer layer 4 may include flexible materials such as non-woven fabric or synthetic resin.

The polishing pad 1 is attached to the polishing device through an adhesive tape or the like provided on the buffer layer 4 . The polishing pad 1 is rotationally driven while being pressed by the polishing device against the object to be polished, and polishes the object to be polished. At this time, slurry is supplied between the polishing pad 1 and the object to be polished. The slurry is fed to the grinding surface through slots or holes and discharged.

<Grinding layer>

The material constituting the polishing layer 2 is the resin 6 which is the main component of the polishing layer 2 . Furthermore, if necessary, hollow microspheres 5 may be further included.

When the polishing layer 2 contains the hollow microspheres 5 , it is preferable that the hollow microspheres 5 are dispersed in the resin 6 as shown in FIG. 2 .

The hollow microspheres 5 that can be included in the polishing layer 2 generally have a spherical shell 5a made of thermoplastic resin and an internal space 5b surrounded by the shell, as shown in FIG. 3 , for example. The hollow microsphere 5 has a shape in which liquid low-boiling hydrocarbons are surrounded by an outer shell 5a of thermoplastic resin.

Details of the resin 6 and the hollow microspheres 5 will be described in the section <<Method for Manufacturing Polishing Pad>>.

<Grinding surface>

The polishing surface 2a of the polishing layer 2 included in the polishing pad 1 of the present invention can be surface processed to provide grooves as necessary. The grooves may be orthogonal grooves (X-axis and Y-axis), perforation-processed grooves (grooves formed by perforation processing), concentric grooves, etc. Sa, Spa, and Spd of the grinding surface will be described later.

<<Manufacturing method of polishing pad>>

The manufacturing method of the polishing pad of this invention is demonstrated. The material of the polishing pad is not particularly limited as long as it can be used for polishing. Examples include polyurethane resin materials obtained by reacting a polyisocyanate compound containing a urethane bond and a hardener. . Hereinafter, the manufacturing method of a polishing pad is demonstrated using the polishing pad of the polyurethane resin obtained using the polyisocyanate compound containing a urethane bond, and a hardener as an example.

An example of a method for manufacturing a polishing pad using a polyisocyanate compound containing a urethane bond and a hardener includes a preparation step of preparing at least a polyisocyanate compound containing a urethane bond. An isocyanate compound, a hardener, and optional hollow microspheres; a mixing step of mixing at least the polyisocyanate compound containing a urethane bond, a hardener, and hollow microspheres to obtain a mixed liquid for molding a molded object; forming a body molding step of molding a polyurethane resin molded body from the molded body molding mixed liquid; and a polishing layer forming step of forming a polishing layer from the polyurethane resin molded body with a surface for polishing The abrasive layer on the abrasive surface of an object for abrasive processing.

Hereinafter, the preparation step, the mixing step, the molded body forming step, and the polishing layer forming step will be described separately.

<Preparation steps>

In order to produce the polishing pad of the present invention, a polyisocyanate compound containing a urethane bond and a curing agent are prepared as raw materials for a polyurethane resin molded article (cured resin). Furthermore, for the purpose of containing a foamed material in the resin molded article, hollow microspheres or water are prepared. Here, polyisocyanates containing urethane linkages are used A prepolymer that forms a polyurethane resin molded article.

In the preparation step, when a polyol compound is further used together with the above-mentioned components, or when components other than the above-mentioned components are used together within a range that does not impair the effects of the present invention, these components are also prepared. Each component is explained below.

[Polyisocyanate compound containing urethane bonds]

A polyisocyanate compound (prepolymer) containing a urethane bond is a compound obtained by reacting the following polyisocyanate compound and a polyol compound under commonly used conditions, and contains a urethane in the molecule bond with the isocyanate group. Moreover, other components may be included in the polyisocyanate compound containing a urethane bond within the range which does not impair the effect of the present invention.

As the polyisocyanate compound containing a urethane bond, a commercially available compound may be used, or a compound synthesized by reacting a polyisocyanate compound with a polyol compound may be used. The reaction is not particularly limited, as long as the addition polymerization reaction is carried out using methods and conditions known in the production of polyurethane resins. For example, a polyisocyanate compound heated to 50°C can be added to a polyol compound heated to 40°C while stirring in a nitrogen atmosphere, and after 30 minutes, the temperature can be raised to 80°C and further reacted at 80°C for 60 minutes. method to manufacture.

[Polyisocyanate compound]

In the scope of this specification and the patent application, a polyisocyanate compound refers to a compound having two or more isocyanate groups in the molecule.

The polyisocyanate compound is not particularly limited as long as it has two or more isocyanate groups in the molecule. For example, having two isocyanate groups in the molecule Examples of diisocyanate compounds include isophenylene diisocyanate, p-phenylene diisocyanate, 2,6-toluene diisocyanate (2,6-TDI), 2,4-toluene diisocyanate (2,4-TDI), naphthalene- 1,4-diisocyanate, diphenylmethane-4,4'-diisocyanate (MDI), 4,4'-methylene-bis(cyclohexyl isocyanate) (hydrogenated MDI), 3,3'-dimethyl Oxy-4,4'-biphenyl diisocyanate, 3,3'-dimethyldiphenylmethane-4,4'-diisocyanate, xylene-1,4-diisocyanate, 4,4'-diisocyanate Phenylpropane diisocyanate, trimethylene diisocyanate, hexamethylene diisocyanate, propylene-1,2-diisocyanate, butene-1,2-diisocyanate, cyclohexene-1,2-diisocyanate, cyclohexene-1,2-diisocyanate, Hexene-1,4-diisocyanate, p-phenylene diisothiocyanate, xylene-1,4-diisothiocyanate, ethylidene diisothiocyanate, etc.

As the polyisocyanate compound, a diisocyanate compound is preferred, among which 2,4-TDI, 2,6-TDI, and MDI are more preferred, and 2,4-TDI and 2,6-TDI are particularly preferred.

These polyisocyanate compounds may be used alone or in combination of a plurality of polyisocyanate compounds.

[Polyol compound as raw material of prepolymer]

In the scope of this specification and the patent application, a polyol compound refers to a compound having two or more hydroxyl groups (OH) in the molecule.

Examples of the polyol compound used in the synthesis of the polyisocyanate compound containing a urethane bond as a prepolymer include glycol compounds such as ethylene glycol, diethylene glycol (DEG), and butylene glycol, and triol compounds. Alcohol compounds, etc.; polyether polyol compounds such as poly(oxytetramethylene) glycol (or polytetramethylene ether glycol) (PTMG); reaction products of ethylene glycol and adipic acid or butanediol Reaction products with hexylene glycol and other polyester polyols Materials; polycarbonate polyol compounds, polycaprolactone polyol compounds, etc. Furthermore, trifunctional propylene glycol to which ethylene oxide is added can also be used. Among these, PTMG or a combination of PTMG and DEG is preferred.

The polyol compound may be used alone or in combination of a plurality of polyol compounds.

(isocyanate (NCO) equivalent of prepolymer)

As an index showing the characteristics of the prepolymer, that is, the polyisocyanate compound containing a urethane bond, the NCO equivalent can be cited. The NCO equivalent is calculated using "(mass part of polyisocyanate compound + mass part of polyol compound)/[(number of functional groups per molecule of polyisocyanate compound × mass part of polyisocyanate compound/molecular weight of polyisocyanate compound)-(polyhydric alcohol compound) The number of functional groups per molecule of the alcohol compound × the mass part of the polyol compound/the molecular weight of the polyol compound)] is a numerical value indicating the molecular weight of PP (prepolymer) per NCO group. The NCO equivalent is preferably 200 to 800, more preferably 300 to 700, and further preferably 400 to 600.

[hardener]

In the method of manufacturing a polishing pad of the present invention, a hardening agent (also called a chain extender) and a polyisocyanate compound containing a urethane bond or the like are mixed in the mixing step. By adding the hardener, in the subsequent step of forming the molded article, the main chain terminals of the polyisocyanate compound containing the urethane bond are bonded to the hardener to form a polymer chain and hardened.

As the hardener, for example, a polyamine compound and/or a polyol compound can be used.

[Polyamine compound]

In the scope of this specification and the patent application, a polyamine compound refers to a compound having two or more amine groups in the molecule.

As the polyamine compound, aliphatic or aromatic polyamine compounds can be used, especially diamine compounds. Examples include: ethylene diamine, propylene diamine, hexamethylene diamine, isophorone diamine, diamine and diamine. Cyclohexylmethane-4,4'-diamine, 3,3'-dichloro-4,4'-diaminodiphenylmethane (methylenebis-o-chloroaniline) (hereinafter referred to as MOCA), Polyamine compounds having the same structure as MOCA, etc. Furthermore, the polyamine compound may have a hydroxyl group. Examples of such amine compounds include 2-hydroxyethylethylenediamine, 2-hydroxyethylpropanediamine, di-2-hydroxyethylethylenediamine, and di- 2-hydroxyethylpropanediamine, 2-hydroxypropylethylenediamine, di-2-hydroxypropylethylenediamine, etc.

As the polyamine compound, a diamine compound is preferred, MOCA, diaminodiphenylmethane, and diaminodiphenylmethane are more preferred, and MOCA is particularly preferred.

Here, examples of MOCA include PANDEX E (manufactured by DIC Corporation), IHARACUAMINE MT (manufactured by KUMIAI CHEMICAL Corporation), and the like.

The polyamine compound may be used alone or in combination of a plurality of polyamine compounds.

In order to easily mix the polyamine compound with other components and/or to improve the uniformity of the bubble diameter in the subsequent molded body forming step, it is preferable to degas the polyamine compound under reduced pressure while being heated, if necessary. As a degassing method under reduced pressure, a method known in the production of polyurethane resin may be used. For example, a vacuum pump may be used to perform degassing at a vacuum degree of 0.1 MPa or less.

In the case of using a solid compound as a hardener (chain extender), it can be It is melted by heating and degassed under reduced pressure.

[Polyol compounds that can be used after prepolymer synthesis]

Furthermore, in the present invention, a polyol compound may be used as a hardener independently of the polyol compound used to form the urethane bond-containing polyisocyanate compound as the prepolymer.

As the polyhydric alcohol compound, any compound such as a dihydric alcohol compound or a trihydric alcohol compound can be used without particular limitation. Furthermore, they may be the same as or different from the polyol compound used to form the prepolymer.

Specific examples include: ethylene glycol, diethylene glycol, triethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,3-butanediol, 1,4-butanediol, new Pentylene glycol, pentylene glycol, 3-methyl-1,5-pentanediol, 1,6-hexanediol and other low molecular weight glycols, poly(oxytetramethylene) glycol, polyethylene glycol , polypropylene glycol and other high molecular weight polyol compounds, etc.

The polyol compound may be used alone or in combination of a plurality of polyol compounds.

As the hardener, a polyamine compound, a polyol compound, or a mixture thereof can be used.

(R value)

In the manufacturing method of the polishing pad of the present invention, it is preferable that the active hydrogen groups (amine groups and hydroxyl groups) present in the hardener are positioned relative to the terminal ends of the polyisocyanate compound containing a urethane bond as a prepolymer. The components are mixed so that the equivalent ratio of the existing isocyanate groups, that is, the R value, becomes 0.60 to 1.40. The R value is preferably 0.70~1.20, and further preferably 0.80~1.10.

[Hollow tiny sphere]

In the method of manufacturing a polishing pad of the present invention, hollow microspheres or water may be used to enclose air bubbles in the polyurethane resin molded body if necessary.

Hollow microspheres refer to microspheres with gaps. Hollow microspheres include spherical, elliptical, and shapes close to these. As an example, what is obtained by heat-expanding unfoamed heat-expandable microspheres is mentioned.

As the polymer shell, as disclosed in Japanese Patent Application Laid-Open No. Sho 57-137323, etc., for example, acrylonitrile-vinylidene chloride copolymer, acrylonitrile-methyl methacrylate copolymer, vinyl chloride can be used. - Thermoplastic resins such as ethylene copolymers. Similarly, as the low-boiling hydrocarbon enclosed in the polymer shell, for example, isobutane, pentane, isopentane, petroleum ether, etc. can be used.

Commercially available hollow microspheres can also be used. For example, Matsumoto microsphere series (manufactured by Matsumoto Oils & Fats Pharmaceutical Co., Ltd.) or Expancel (manufactured by AkzoNobel) can be used as hollow microspheres. Commercially available hollow microspheres include expanded types that have been heated and expanded and unexpanded types that have not been heated and expanded. The expanded type is hardly affected by the reaction heat generated by the mixing step described below and can achieve a fixed bubble diameter. On the other hand, the unexpanded type expands due to the reaction heat generated by the mixing step described below. Therefore, in the case of the unexpanded type, in order to control the bubble diameter, it is necessary to quickly cool the reaction heat generated by the polymerization reaction or to quickly accelerate the polymerization reaction, for example, by forcing the resin around the hollow microspheres to To suppress expansion and other reaction conditions.

As the average particle diameter of the hollow microspheres, it is preferable to use hollow microspheres of 10 μm to 150 μm. The average particle diameter of the expanded hollow microspheres is more preferably 15 μm to 130 μm, further preferably 20 μm to 100 μm, still more preferably 20 μm to 60 μm, and particularly preferably 30 μm to 50 μm. In addition, the expanded type has already expanded, so the average particle diameter of the hollow microspheres before the resin is included and the average bubble diameter of the hollow microspheres after the polishing layer is formed do not change much.

Furthermore, only the expanded type with an average particle diameter of 20 μm or more is commercially available. Therefore, if the bubble diameter in the resin is to be less than 20 μm, it is necessary to use unexpanded hollow microspheres with an average particle diameter of 10 μm to 20 μm. The reaction conditions are adjusted so that the hollow microspheres hardly expand and are controlled. The average particle diameter of the unexpanded hollow microspheres is preferably 10 μm to 20 μm. After each step described below, the average bubble diameter of the bubbles dispersed in the polyurethane resin of the polishing layer is preferably 10μm~20μm, more preferably 12μm~20μm, more preferably 15μm~20μm.

In addition, the average particle diameter of the hollow microspheres before use can be measured with a laser diffraction particle size distribution measuring device (for example, a particle size analyzer (mastersizer) 2000 manufactured by Spectris Co., Ltd.).

Furthermore, the average bubble diameter of the hollow microspheres in the polishing pad can be measured by image processing from a measurement image obtained by a laser microscope.

The hollow microspheres are preferably 10 volume % to 60 volume % relative to the material of the grinding layer, and more preferably 15 volume % to 45 volume %. After the grinding layer is worn due to grinding, the hollow microspheres are exposed to the grinding surface, affecting the grinding characteristics of the grinding surface.

The hollow microspheres are added in an amount relative to 100 parts by mass of the prepolymer, preferably 0.1 to 10 parts by mass, more preferably 1 to 5 parts by mass, and further preferably 2 to 4 parts by mass. .

<Mixing step>

In the mixing step, the polyisocyanate compound (prepolymer) containing a urethane bond and the hardener obtained in the preparation step are supplied into a mixer and stirred and mixed. The mixing step is performed while heating to a temperature that ensures the fluidity of each component.

In the mixing step, at least the polyisocyanate compound (prepolymer) containing a urethane bond, the hardener, and the hollow microspheres are supplied into the mixer and stirred and mixed. The mixing order is not particularly limited, but it is preferable to prepare a mixed liquid of a polyisocyanate compound containing a urethane bond and hollow microspheres, and a mixed liquid of a hardener and optional other components. The two mixed liquids are fed into the mixer for mixing and stirring. In this way, a mixed liquid for molding a molded body is prepared. The mixing step is performed while heating to a temperature that ensures the fluidity of each component.

<Process for molding the molded body>

In the molding step, the mixed liquid for molding prepared in the mixing step is poured into a mold frame preheated to 30°C to 100°C, and then hardened once at 100°C to 150°C. The polyurethane resin is heated for about 10 minutes to about 5 hours at a temperature of about 10° C. to perform secondary hardening to form a hardened polyurethane resin (polyurethane resin molded article). At this time, the prepolymer and the hardener react to form a polyurethane resin, thereby hardening the mixed liquid.

<Steps for forming polishing layer>

The polyurethane resin molded article obtained by the molded article forming step is sliced into a sheet form to form a polyurethane resin sheet. By being sliced, openings can be provided on the surface of the sheet. At this time, in order to form openings on the surface of the polishing layer that have excellent wear resistance and are not easily clogged, aging can also be performed at 30°C to 150°C for about 1 hour to 24 hours.

The polishing layer having the polyurethane resin sheet thus obtained is then affixed with a double-sided tape on the surface opposite to the polishing surface of the polishing layer, and is cut into a predetermined shape, preferably a disc shape, and This is completed as the polishing pad of the present invention. The double-sided tape is not particularly limited, and any double-sided tape known in the technical field can be selected and used.

Furthermore, the polishing pad of the present invention may have a single-layer structure including only a polishing layer, or may have a polishing layer having other layers (lower layer, support layer, buffer layer in FIG. 1 ) bonded to the surface opposite to the polishing surface. ) of multiple layers. The characteristics of the other layers are not particularly limited, but it is preferable that a layer softer than the polishing layer (A hardness or D hardness is smaller) is bonded to the surface opposite to the polishing surface of the polishing layer. If a layer softer than the polishing layer is bonded, the polishing flatness will be further improved. On the other hand, if a layer harder than the polishing layer (A hardness or D hardness is high) is bonded to the surface of the polishing layer opposite to the polishing surface, the polishing rate will be further improved.

In the case of a multi-layer structure, the multiple layers may be adhered/fixed to each other using double-sided tape, an adhesive, or the like (pressure is applied as necessary). The double-sided tape or adhesive used at this time is not particularly limited, and any double-sided tape or adhesive known in the technical field can be selected and used.

Furthermore, the polishing pad of the present invention may grind the surface and/or back of the polishing layer as needed, or perform groove processing or embossing processing on the surface, and may bond the base material and/or the adhesive layer to the polishing layer, or may Includes light transmitting part.

The shape of groove processing and embossing processing is not particularly limited, and examples thereof include grid type, concentric circle type, radial type, and the like.

[Surface treatment]

The polishing surface of the polishing pad of the present invention can be subjected to physical or chemical treatment. Without surface treatment, as long as the grinding surface can be made into the specified range of Sa and Spc (and Spd if necessary), the running-in time can still be shortened and defects can be reduced. However, if surface treatment is performed, it is easier to achieve the specified Sa and Spc, so it is preferable to perform surface treatment.

Furthermore, conventional surface roughness only measures Ra in a specific line direction using a contact method as an index. However, it is difficult to measure an accurate surface state when the direction of surface treatment (rotation direction, etc.) deviates in a specific direction. By measuring surface roughness using an optical method, the present invention can measure an accurate surface state taking directionality into consideration.

In the polishing pad of the present invention, one surface treatment method for achieving Sa and Spc (and Spd if necessary) within a predetermined range is polishing treatment. Therefore, the polishing pad of the present invention is preferably polished. Here, the polishing process is a method of roughening the polishing surface to a certain extent using sandpaper, and then pressing a polishing tool such as cloth, leather, or rubber onto the polishing surface while rotating, to treat the surface.

The grit number of the sandpaper used for polishing in the present invention is not particularly limited, and is preferably #120~#600. This is because by using this kind of sandpaper, it is easy to adjust to the appropriate Sa and Spc.

In the present invention, the circumferential speed of the sandpaper in the polishing process is not particularly limited, but is preferably 300m/min~1500m/min. When the paper peripheral speed is less than 300 m/min, the cutting force becomes low and the surface may not be sufficiently roughened. Furthermore, when the paper circumferential speed exceeds 1500 m/min, the cutting force becomes too large and it becomes difficult to achieve the prescribed ranges of Sa and Spc (and Spd if necessary).

In the present invention, the platform speed when pressing the polishing part during the polishing process is not particularly limited, but is preferably 0.1m/min~20m/min.

In the present invention, it is preferable to set the ratio of the paper circumferential speed to the platform speed (paper circumferential speed/platform speed) to 50 to 750. By making the platen speed sufficiently slower than the paper speed, the shearing force can be suppressed while setting the cutting force to a preferable range, thereby achieving a predetermined range of Sa and Spc (if necessary). Spd). When the paper circumferential speed/platform speed is less than 50, shearing force is generated, undesirable tearing occurs, the peak points become sharp, or the number of peak points increases, making it difficult to achieve the prescribed ranges of Sa, Spc, and Spd. Furthermore, when the paper peripheral speed/platen speed is greater than 750, the cutting force becomes too large, making it difficult to achieve the prescribed ranges of Sa, Spc, and Spd.

The polishing pad of the present invention includes a polishing layer having Sa, Spc, and Spd in a prescribed range without surface treatment or, if necessary, by performing surface treatment such as such polishing treatment.

In the present invention, Sa of the polishing surface of the polishing layer is 3 μm to 10 μm. If it is within this range, the running-in time can be shortened. The lower limit of Sa is preferably 3 μm or more, more preferably 4 μm or more. On the other hand, the upper limit of Sa is preferably 10 μm or less, more preferably 8 μm or less.

In the present invention, the Spc of the polishing surface of the polishing layer is 200 to 600 (1/mm). If it is within this range, it will have the effect of reducing scratches. The lower limit of Spc is preferably 200 (1/mm) or more, more preferably 300 (1/mm) or more. On the other hand, the upper limit of Spc is preferably 600 (1/mm) or less, more preferably 500 (1/mm) or less.

In the present invention, the Spd of the polishing surface of the polishing layer is preferably 2000 to 6000 (1/mm ² ). If it is within this range, it has the effect of reducing scratches, so it is preferable. The lower limit of Spd is preferably 2000 (1/mm ² ) or more, more preferably 3000 (1/mm ² ) or more. On the other hand, the upper limit of Spd is preferably 6000 (1/mm ² ) or less, more preferably 5000 (1/mm ² ) or less.

When using the polishing pad of the present invention, the polishing pad is installed on the polishing platform of the polishing machine in such a manner that the polishing surface of the polishing layer faces the object to be polished. Furthermore, while supplying the polishing slurry, the polishing table is rotated to polish the processed surface of the object to be polished.

[Example]

Hereinafter, the present invention will be described in detail using examples, but the present invention is not limited to the examples.

(Measurement of surface condition)

Sa, Spc and Spd are measured using a laser microscope.

(evaluation of defects)

The polishing pad is placed on the polishing device via a double-sided tape with an acrylic adhesive. The Cu film substrate is placed at a specified position and polished under the following conditions.

(Grinding conditions)

Grinding machine: F-REX300 (manufactured by Ebara Seisakusho Co., Ltd.)

Disk: A188 (manufactured by 3M Company)

Speed: (platform) 70rpm, (top ring) 71rpm

Grinding pressure: 3.5psi

Abrasive temperature: 20℃

Abrasive spray volume: 200ml/min

Abrasive: PLANERLITE7000 (manufactured by Fujimi Corporation)

Object to be polished: Cu film substrate

Grinding time: 60 seconds Pad break: 35N 10 minutes

Conditioning: Ex-situ, 35N, 4 scans

For the 10th to 50th piece of the polished object after the above-mentioned polishing process, for the linear polishing scratches (scratches) and dot-shaped polishing scratches (micro scratches) larger than 155nm on the polished surface, use The number of scratches was visually confirmed using ReviewSEM of eDR5210 (manufactured by KLA-Tencor).

(Refer to the manufacturing of polishing pads)

Isocyanate group-terminated carbamic acid with an NCO equivalent of 460 obtained by reacting 2,4-toluene diisocyanate (TDI), poly(oxytetramethylene) glycol (PTMG) and diethylene glycol (DEG) To 100 parts of the ester prepolymer, add a mixed shell containing an unexpanded medium containing an acrylonitrile-vinylidene chloride copolymer and isobutane gas inside the shell. Empty 3 parts to obtain a mixed solution. The obtained mixed liquid is put into the first liquid tank and kept warm. Next, independently of the first liquid, 25.5 parts of MOCA and 8.5 parts of polypropylene glycol (PPG) were added and mixed as a hardener, and the heat was maintained in the second liquid tank. Each liquid in the first liquid tank and the second liquid tank has two injection holes so that the R value indicating the equivalent ratio of the amine groups and hydroxyl groups present in the hardener to the terminal isocyanate group in the prepolymer becomes 0.90. The inlet of the mixer is injected into the mixer through its respective injection port. The two injected liquids are mixed and stirred while being poured into the metal mold of the preheated molding machine, and then the mold is closed and heated for 30 minutes to perform primary hardening. After demolding the primary hardened molded article, secondary hardening was performed in an oven at 130° C. for 2 hours to obtain a urethane molded article. The obtained urethane molded product was left to cool to 25° C., and then heated again in an oven at 120° C. for 5 hours, and then sliced into a thickness of 1.3 mm to obtain a polishing pad. The average bubble diameter of the obtained polishing pad was 15 μm.

(Refer to the polishing process of the polishing pad)

The obtained polishing pad was not polished but polished. As the polishing treatment, a dresser is used to polish the surface of the polishing pad a certain amount. As the polisher, a trade name "F-REX300" manufactured by Ebara Seisakusho Co., Ltd. is used, and the table rotation speed is set to 80 rpm, the polishing pressure was set to 20N, the slurry discharge volume was set to 1.5L/min, and pure water was used as the slurry to perform dressing for 10 minutes. The SEM photograph of the polishing surface of the obtained reference polishing pad is shown in FIG. 4 .

The polished reference polishing pad was used, and the test polished sample was used for polishing. The grinding speed is not sufficient, so grind the areas alternately. Preliminary grinding of the processing and test samples, and the target grinding speed becomes the 25th grinding process. Furthermore, when the reference polishing pad was used, it was confirmed that the number of scratches was 3 and the number of minute scratches was 25, indicating that there were few polishing wounds (scratches).

At this time, the Sa of the polishing surface of the reference polishing pad was 4.7, the Spc was 490, and the Spd was 4800.

(Example 1)

For a polishing pad obtained by the same manufacturing method as the reference polishing pad, without polishing, using paper with a particle size of #240, under the conditions of paper peripheral speed (500m/min) and platform speed (1m/min) The polishing process was performed so that the remainder would become 50 micrometers, and the polishing pad A was obtained. Sa, Spc, and Spd of the surface of the polishing surface of polishing pad A (after polishing treatment) were measured four times and averaged. The respective results are, Sa is 4.3, Spc is 420, and Spd is 3600. The SEM photograph of the polishing surface of the polishing pad of Example 1 obtained is shown in FIG. 5 .

A polishing test was conducted using this polishing pad A, and the results showed that the polishing rate was sufficient even without polishing. That is, the running-in time can be shortened. Furthermore, it was confirmed that the number of scratches was 2, the number of minute scratches was 18, and there were few polishing scratches (scratches).

(Example 2)

For a polishing pad obtained by the same manufacturing method as the reference polishing pad, without polishing, using paper with a particle size of #180, under the conditions of paper peripheral speed (500m/min) and platform speed (1m/min) Polishing is performed to obtain polishing pad B. Sa, Spc, and Spd of the surface of the polishing surface of polishing pad B (after polishing treatment) were measured four times and averaged. The respective results are, Sa is 5.4, Spc is 480, Spd is 4500. The SEM photograph of the polishing surface of the polishing pad of Example 2 obtained is shown in FIG. 6 .

A polishing test was conducted using this polishing pad B. As a result, the polishing rate was sufficient even without polishing. That is, the running-in time can be shortened. Furthermore, it was confirmed that the number of scratches was 4, the number of minute scratches was 26, and there were few polishing scratches (scratches).

(Comparative example 1)

For the polishing pad obtained by the same manufacturing method as the reference polishing pad, use paper with a particle size of #120 and perform polishing under the conditions of paper peripheral speed (1000m/min) and platform speed (1m/min). This obtains polishing pad C. Sa, Spc, and Spd of the surface of the polishing surface of polishing pad C (after polishing treatment) were measured four times and averaged. The respective results are, Sa is 6.3, Spc is 800, and Spd is 8200. The SEM photograph of the polishing surface of the polishing pad of Comparative Example 1 obtained is shown in FIG. 7 .

A polishing test was conducted using this polishing pad C. As a result, although the running-in time could be shortened, the number of scratches was 9 and the number of micro-scratches was 42, indicating that there were more polishing wounds (scratches) than in the Example.

Comparing the polishing pad C of Comparative Example 1 with a reference polishing pad that has a sufficient polishing rate and few defects, the values of Ra are almost the same, but it cannot be said to be an excellent polishing pad in terms of defects. It is thought that the reason is that the values of Sa, Spc, Spd, etc. are not within the prescribed range.

On the other hand, it is considered that polishing pad A and polishing pad B can shorten the running-in time and have fewer defects because they have the same Ra, Sa, and Spc as the polished reference polishing pad, and furthermore the same Spd.

1: Polishing pad

2: Grinding layer

2a: grinding surface

3:Add layer

4: Buffer layer

Claims (2)

A polishing pad having a polishing layer for polishing an object to be polished, the polishing pad being characterized by an average arithmetic mean height (Sa ) is 4 to 8 (μm), and the average of the main curvatures of the peak apex of the polishing surface, that is, the arithmetic mean curvature (Spc) of the peak apex, is 300 to 500 (1/mm), indicating the per unit area of the polishing surface The peak apex density (Spd) of the number of peak apexes is 3000~5000 (1/mm ² ). A method for manufacturing a polishing pad, which is a method for manufacturing a polishing pad as described in item 1 of the patent application scope, including under the condition that the ratio of paper circumferential speed to platform speed (paper circumferential speed/platform speed) is 50 to 750 Steps to implement the polishing process.