Polishing pad, polishing apparatus, and method of manufacturing semiconductor device

Abstract

The present application discloses a polishing pad, a polishing device and a method for manufacturing a semiconductor device, which are related to the technical field of chemical mechanical polishing of semiconductors. The polishing pad has a polishing surface, and from the center of the polishing surface to the outer edge, at least first, second and third annular polishing unit groups are arranged in sequence on the polishing surface. The polishing area ratio of the second annular unit group is greater than that of the first annular polishing unit group, and the polishing area ratio of the second annular unit group is greater than that of the third annular polishing unit group. The wafer can be polished by using the polishing pad provided by the present application, and the wafer with excellent polishing rate, low polishing rate inhomogeneity and low surface defects can be obtained.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of chemical mechanical polishing of semiconductors, and more particularly, to a polishing pad, a polishing apparatus and a method for manufacturing a semiconductor device. BACKGROUND

[0002] Chemical mechanical planarization or chemical mechanical polishing (CMP) is the most common technique used for polishing the surface of a workpiece. CMP is a combination of chemical attack and mechanical removal and is the most common technique for planarization of semiconductor wafers and the like.

[0003] In a conventional CMP process, a wafer is mounted on a carrier assembly of a polishing apparatus, and the position of the wafer in contact with a polishing pad during polishing is set by adjusting relevant parameters. During polishing, the wafer is pressed against the polishing pad by a controllable pressure, and the polishing pad is rotated in the same or opposite direction as the wafer by an external drive. During the relative rotation, a polishing liquid is continuously dripped onto the polishing pad, so that the wafer surface is planarized by the mechanical action of the polishing pad surface and the chemical action of the polishing liquid, thereby achieving polishing of the wafer.

[0004] The shape and size of the surface grooves of the polishing pad, as one of the key parameters determining the performance of the polishing pad, have an important influence on the chemical and mechanical processes of polishing: in the chemical oxidation process, the surface grooves of the polishing pad affect the transport and distribution of the polishing liquid, thereby affecting the chemical reaction rate, the product and its concentration; in the mechanical removal process, the surface grooves of the polishing pad change the contact area between the polishing pad and the wafer, the friction and the film thickness, thereby affecting the mechanical removal rate and the processing quality, and also have an important influence on the average residence time of the polishing liquid.

[0005] During the relative rotation of the polishing pad and the wafer, the polishing rate of each position of the wafer is affected by the grooves on the polishing pad and the distribution of the polishing liquid, and there is a problem of whether the flatness of the wafer meets the requirements. As the integration level of integrated circuits increases, the flatness of the wafer will directly affect the utilization rate of the substrate, and further affect the process yield of the integrated circuit. Therefore, obtaining a wafer with high flatness is one of the problems faced by the integrated circuit manufacturing industry.

[0006] For manufacturers of chemical mechanical polishing pads, the polishing rate and the wafer surface defects are one of the important indicators for evaluating the performance of the polishing pad. The polishing rate is also an indicator of the production efficiency of the polishing pad for polishing wafers, and the wafer surface defects are an indicator for evaluating the polishing effect of the polishing pad. Therefore, on the basis of improving the polishing flatness of the wafer, the basic indicators such as the polishing rate and the wafer surface defects should not be sacrificed. SUMMARY

[0007] The present application aims to solve the above technical problems, and provides a polishing pad, a polishing apparatus, and a method for manufacturing a semiconductor device.

[0008] The present application provides a polishing pad having a polishing surface, wherein a first annular polishing unit group, a second annular polishing unit group, and a third annular polishing unit group are sequentially arranged from the center of the polishing surface to the periphery of the polishing surface; the polishing area ratio of the second annular unit group is greater than that of the first annular polishing unit group, and the polishing area ratio of the second annular unit group is greater than that of the third annular polishing unit group.

[0009] Further, the polishing area ratios of the first annular polishing unit group, the second annular polishing unit group, and the third annular polishing unit group are all 0.60-0.95, preferably 0.7-0.9; wherein the polishing area ratios of the first annular polishing unit group and the third annular polishing unit group are equal or unequal.

[0010] Further, the width R2 of the second annular polishing unit group is 0.33-0.67, preferably 0.55-0.65, of the diameter D of the material to be polished. Further, the width R1 of the first annular polishing unit group is equal to or unequal to the width R3 of the third annular polishing unit group. W

[0011] Further, the adjacent annular groove spacing D1 of the first annular polishing unit group is less than the adjacent annular groove spacing D2 of the second annular polishing unit group, and the adjacent annular groove spacing D3 of the third annular polishing unit group is less than the adjacent annular groove spacing D2 of the second annular polishing unit group, wherein D1 and D3 are equal or unequal.

[0012] Further, D2 is 1.2-3 times, preferably 1.5-2.5 times, more preferably 2 times, of D1; and D2 is 1.2-3 times, preferably 1.5-2.5 times, more preferably 2 times, of D3.

[0013] Further, the annular groove depth of the first annular polishing unit group is denoted as H1, the annular groove depth of the second annular polishing unit group is denoted as H2, and the annular groove depth of the third annular polishing unit group is denoted as H3; wherein H1, H2, and H3 are 0.02-0.8 times, preferably 0.15-0.6 times, of the thickness of the polishing layer. Further, H1, H2, and H3 are equal or unequal, preferably H1>H2, and / or H3>H2.

[0014] Further, the polishing pad is used for polishing a metal layer or an oxide layer, and the metal layer includes any one of a copper layer, a tungsten layer, and an aluminum layer.

[0015] ​The second aspect of the present application provides a polishing apparatus having a polishing pad in contact with a workpiece to be polished, the polishing pad being the polishing pad according to the first aspect of the present application.

[0016] The third aspect of the present application provides a method of manufacturing a semiconductor device, including a step of polishing a surface of a semiconductor wafer using a polishing pad, the polishing pad being the polishing pad according to the first aspect of the present application.

[0017] Compared with the prior art, the present application has the following beneficial effects: the polishing pad according to the present application can be used to polish a wafer, and a wafer with excellent polishing rate, low polishing rate non-uniformity and low surface defects can be obtained. BRIEF DESCRIPTION OF DRAWINGS

[0018] Figure 1 A polishing pad according to a preferred embodiment of the present application has a surface groove structure;

[0019] Figure 2 A polishing pad according to the present application Figure 1 A front view of a section A-A. DETAILED DESCRIPTION

[0020] The present application provides a polishing pad, a polishing apparatus and a method of manufacturing a semiconductor device, which will be described below in conjunction with specific embodiments. It should be noted that the terms "first", "second", "third" and the like used in the present application do not indicate any order, quantity or importance, but are used to distinguish different components. The following examples are only used to illustrate the present application and do not limit the present application. Other combinations and various modifications within the concept of the present application can be made without departing from the spirit or scope of the present application.

[0021] [Polishing pad]

[0022] The first aspect of the present application provides a polishing pad having a polishing surface, wherein a first annular polishing unit group, a second annular polishing unit group and a third annular polishing unit group are sequentially arranged from the center of the polishing surface to the periphery of the polishing surface. The polishing surface of the present application is the contact surface between the polishing pad and the wafer.

[0023] In the specific embodiments of the present application, as shown in Figure 1 the polishing surface of the polishing pad, a center blank area is further provided at the center of the polishing surface, and an edge blank area is further provided at the edge of the polishing surface, and the first annular polishing unit group, the second annular polishing unit group and the third annular polishing unit group are sequentially arranged from the inside to the outside between the center blank area and the edge blank area. In the present application, the first annular polishing unit group, the second annular polishing unit group and the third annular polishing unit group are regions respectively grooved at equal intervals to form annular polishing units.

[0024] The center blank area is circular and the edge blank area is annular. No grooves are formed in the center blank area and the edge blank area. The radius of the polishing pad is defined as R, the radius of the center blank area is defined as R0, the width of the edge blank area is defined as e, the width of the first annular polishing unit group is defined as R1, the width of the second annular polishing unit group is defined as R2, and the width of the third annular polishing unit group is defined as R3. Thus, R = R0 + R1 + R2 + R3 + e.

[0025] In the embodiments of the present application, the radius R0 of the center blank area is 5-15 mm, such as 7.5 mm, 11.7 mm, 12.2 mm, 12.7 mm, 13.2 mm, 14 mm, etc. The width e of the edge blank area is 0.2-4.0 mm, such as 0.24 mm, 0.32 mm, 0.36 mm, 0.40 mm, 0.50 mm, 0.60 mm, 1.0 mm, 2.0 mm, 3.0 mm, 3.8 mm, etc. The diameter of the polishing layer is 50-100 cm, which can be used to polish an 8-inch wafer, i.e. the diameter D w of the wafer is 203.2 mm; can also be used to polish a 12-inch wafer, i.e. the diameter D w of the wafer is 304.8 mm; and can also be used to polish an 18-inch wafer, i.e. the diameter D w of the wafer is 457.2 mm. The thickness of the polishing layer is 1.1-3.6 mm, and the more common thicknesses are 1.27 mm and 2.032 mm.

[0026] In the process of polishing the wafer with the polishing pad, the wafer is located in the radius area of the polishing surface, and the part of the wafer in contact with the polishing pad comprises the second annular polishing unit group and part of the first annular polishing unit group and part of the third annular polishing unit group, i.e. in the process of rotating the polishing pad and the wafer in the same or opposite directions, the second annular polishing unit group grinds the center area of the wafer. According to the size of the wafer, the width of the polishing pad and the second annular polishing unit group is adjusted. In the present application, the width R2 of the second annular polishing unit group is 0.33-0.67, preferably 0.55-0.65, of the diameter D W of the wafer to be ground, i.e. the wafer. Preferably, the center of the wafer coincides with any position at 1 / 2 of the width of the second annular polishing unit group, i.e. the area of the wafer ground on the first annular polishing unit group and the third annular polishing unit group is equal in width.

[0027] Further, the width R1 of the first annular polishing unit group and the width R3 of the third annular polishing unit group are equal or not equal in the present application, and the first annular polishing unit group and the third annular polishing unit group grind the edge area of the wafer. The width of the first annular polishing unit group and the third annular polishing unit group can achieve complete grinding of the wafer.

[0028] In a specific embodiment of the present invention, the groove size on the first annular grinding unit group is defined. The width of the annular groove on the first annular grinding unit group is denoted as W1, the distance between adjacent annular grooves is denoted as D1, the depth of the annular groove is denoted as H1, and the number of annular grooves is denoted as n1. If the groove widths on the first annular grinding unit group are equal and the spacing is equal, then the number of grooves R1 = n1 * (W1 + D1).

[0029] In a specific embodiment of the present invention, the annular grooves on the first annular grinding unit group have equal widths and equal spacing. Therefore, the area S of the innermost annular groove on the first annular grinding unit group is [missing information - likely a value or measure]. 1最内 =π*(R0+W1) 2 -π*R0 2 =π*W1*(W1+2R0); Area S of the outermost annular groove 1最外 =π*[R0+n1W1+(n1-1)D1] 2 -π*[R0+(n1-1)W1+(n1-1)D1] 2 =π* W1*[2 R0+(2n1-1) W1+(2n1-2)D1]; The area of ​​each annular groove is an arithmetic sequence with a common difference of π*W1*(2W1+2D1).

[0030] Then the sum of the groove areas of the first annular grinding unit group, S1 = (S 1最内 +S 1最外 ) *n1 / 2=π* W1*[4 R0+2n1*W1+(2n1-2)D1] *n1 / 2;The grinding area ratio of the first annular grinding unit group RS1=[π(R0+R1)] 2 -πR0 2 -S1] / [π(R0+R1) 2 -πR0 2 ].

[0031] In a specific embodiment of the present invention, the groove size on the second annular grinding unit group is defined as follows: the width of the annular groove on the second annular grinding unit group is denoted as W2, the distance between adjacent annular grooves is denoted as D2, the depth of the annular groove is denoted as H2, and the number of annular grooves is n2. Since the groove widths on the second annular grinding unit group are equal and the spacing is equal, the number of grooves R2 = n2 * (W2 + D2).

[0032] In a specific embodiment of the present invention, the annular grooves on the second annular grinding unit group have equal widths and equal spacing. Therefore, the area S of the innermost annular groove on the second annular grinding unit group is [missing information - likely a value or measure]. 2最内 =π*(R0+R1+W2) 2 -π*(R0+R1)2 =π*W2*[W2+2(R0+R1)]; Area S of the outermost annular groove 2最外 =π*[R0+R1+n2W2+(n2-1)D2] 2 -π*[R0+R1+(n2-1)W2+(n2-1)D2] 2 =π*W2*[2(R0+R1)+(2n2-1) W2+(2n2-2)D2]; The area of ​​each annular groove is an arithmetic sequence with a common difference of π*W2*(2W2+2D2).

[0033] Then the sum of the groove areas of the second annular grinding unit group, S2 = (S 2最内 +S 2最外 ) *n2 / 2=π*W2*[4 (R0+R1)+2n2*W2+(2n2-2)D2] *n2 / 2;The grinding area ratio of the second annular grinding unit group RS2=[π(R0+R1+R2) 2 -π(R0+R1) 2 -S2] / [π(R0+R1+R2) 2 -π(R0+R1) 2 ].

[0034] In a specific embodiment of the present invention, the groove size on the third annular grinding unit group is defined as follows: the width of the annular groove on the third annular grinding unit group is denoted as W3, the distance between adjacent annular grooves is denoted as D3, the depth of the annular groove is denoted as H3, and the number of annular grooves is denoted as n3. Since the groove widths on the third annular grinding unit group are equal and the spacing is equal, then R3 = (n3-1)*(W3+ D3)+W3.

[0035] In a specific embodiment of the present invention, the annular grooves on the second annular grinding unit group have equal widths and equal spacing. Therefore, the area S of the innermost annular groove on the third annular grinding unit group is [missing information - likely a value or measure]. 3最内 =π*(R0+R1+R2+W3) 2 -π*(R0+R1+R2) 2 =π*W3*[W3+2(R0+R1+R2)];

[0036] The area S of the outermost annular groove on the third annular grinding unit group 3最外 =π*[R0+R1+R2+n3W3+(n3-1)D3] 2 -π*[R0+R1+R2+(n3-1)W3+(n3-1)D3] 2=π*W3*[2(R0+R1+R2)+(2n3-1) W3+(2n3-2)D3]; The area of ​​each annular groove is an arithmetic sequence with a common difference of π*W3*(2W3+2D3).

[0037] Then the sum of the groove areas of the third annular grinding unit group, S3 = (S 3最内 +S 3最外 ) *n3 / 2=π*W3*[4 (R0+R1+R2)+2n3*W3+(2n3-2)D3] *n3 / 2;The grinding area ratio of the third annular grinding unit group RS3=[π(R0+R1+R2+R3) 2 -π(R0+R1+R2) 2 -S3] / [π(R0+R1+R2+R3) 2 -π(R0+R1+R2) 2 ].

[0038] To obtain a wafer with high flatness, the grinding area ratio RS2 of the second annular unit group is greater than the grinding area ratio RS1 of the first annular grinding unit group, and the grinding area ratio RS2 of the second annular unit group is greater than the grinding area ratio RS3 of the third annular grinding unit group. Preferably, RS1, RS2, and RS3 are all 0.60~0.95, more preferably 0.7~0.9, such as 0.72, 0.74, 0.76, 0.78, 0.80, 0.82, 0.84, 0.86, 0.88, and 0.90. RS1 and RS3 may be equal or unequal.

[0039] Furthermore, the widths W1, W2, and W3 of the annular grooves on the first, second, and third annular grinding unit groups of the present invention are equal or unequal, preferably equal. Specifically, W1, W2, and W3 are 0.2~0.6 mm, preferably 0.36~0.55 mm; examples include: 0.22 mm, 0.28 mm, 0.32 mm, 0.35 mm, 0.39 mm, 0.42 mm, 0.44 mm, 0.46 mm, 0.48 mm, 0.50 mm, 0.52 mm, 0.54 mm, 0.56 mm, and 0.58 mm. If W1, W2, and W3 are too small, it is not conducive to the rapid and uniform dispersion of the polishing slurry; if W1, W2, and W3 are too large, polishing slurry aggregation is likely to occur, leading to chemical polishing aggregation, which is not conducive to uniform polishing.

[0040] Further, the distance D1 between adjacent annular grooves of the first annular polishing unit group, the distance D2 between adjacent annular grooves of the second annular polishing unit group, and the distance D3 between adjacent annular grooves of the third annular polishing unit group are all 1.0-4 mm, preferably 1.2-3.2 mm, and examples of the distances can be 1.1 mm, 1.2 mm, 1.3 mm, 1.4 mm, 1.5 mm, 1.6 mm, 1.8 mm, 2.0 mm, 2.2 mm, 2.4 mm, 2.6 mm, 2.8 mm, 3.0 mm, 3.2 mm, 3.4 mm, 3.6 mm, 3.8 mm. To achieve the technical effects of the present application, the distance D1 between adjacent annular grooves of the first annular polishing unit group is less than the distance D2 between adjacent annular grooves of the second annular polishing unit group, and the distance D3 between adjacent annular grooves of the third annular polishing unit group is less than the distance D2 between adjacent annular grooves of the second annular polishing unit group, wherein the distance D1 and the distance D3 are equal or different. Specifically, the distance D2 is 1.2-3 times, preferably 1.5-2.5 times, and more preferably 2 times the distance D1, and the distance D2 is 1.2-3 times, preferably 1.5-2.5 times, and more preferably 2 times the distance D3.

[0041] Further, the depth of the grooves in each annular polishing unit group is 0.02-0.8 times, and preferably 0.15-0.6 times the thickness H of the polishing layer. Specifically, the depths H1, H2 and H3 are equal or different. From the perspective of improving the flatness of the wafer, it is preferred that H1>H2, and / or H3>H2. More preferably, H1 and H3 are equal.

[0042] Further, the polishing pad is used for polishing a metal layer or an oxide layer, and the metal layer includes any one of a copper layer, a tungsten layer, and an aluminum layer.

[0043] In the present application, the diameter of the polishing layer is 50-100 cm, and preferably 50-90 cm, and the thickness of the polishing layer is 1.1-3.6 mm, and a common thickness is 1.27 mm or 2.032 mm. In the embodiment of the present application, the diameter of the polishing layer is 77.47 cm, and the thickness is 2.032 mm.

[0044] <Preparation of the polishing pad>

[0045] The polishing pad of the present application includes a polishing layer, and can further include a buffer layer. The polishing layer and the buffer layer can be self-prepared using the following method, or can be directly purchased from a commercial product. The method for bonding the polishing layer and the buffer layer to prepare the polishing pad is not particularly limited, and the following method can be listed, i.e., a method of laminating an adhesive layer composed of a polyester hot melt adhesive on the buffer layer, heating the adhesive layer with a heater to melt the adhesive layer, and then laminating and pressing the polishing layer on the molten adhesive layer.

[0046] As the polishing layer, the polishing layer of the present application can be prepared by using a known prepolymer method, one-step method, etc. The method selected by the skilled person in the art according to the need does not affect the concept and protection scope of the present application, as long as the polishing layer involved in the present application can be made.

[0047] The material of the polishing layer is a material commonly used in the art, such as polyurethane, which refers to a product derived from di-functional or multi-functional isocyanate, and the polyurethane can be one or more of polyether urea, polyisocyanurate, polyurethane, polyurea and polyurethane urea, or a copolymer formed by two or more of polyether urea, polyisocyanurate, polyurethane, polyurea and polyurethane urea. Preferably, the polyurethane is prepared by reacting isocyanate and polyol to obtain an isocyanate-terminated prepolymer, and then reacting with a curing agent, or by reacting isocyanate and polyol to obtain an isocyanate-terminated prepolymer, and then reacting with a mixture of a curing agent and hollow microspheres.

[0048] The isocyanate, if not particularly limited, can be a compound known in the art of polyurethane, such as an aromatic isocyanate and / or an aliphatic isocyanate. The isocyanate can be one or more of an aromatic diisocyanate compound, an aliphatic diisocyanate compound and a cycloaliphatic diisocyanate compound. The aromatic diisocyanate compound is preferably one or more of 2,4-toluene diisocyanate, 2,6-toluene diisocyanate, 2,2'-diphenylmethane diisocyanate, 2,4'-diphenylmethane diisocyanate, 4,4'-diphenylmethane diisocyanate, 1,5-naphthalene diisocyanate, p-phenylene diisocyanate, m-phenylene diisocyanate, p-xylylene diisocyanate and m-xylylene diisocyanate. The aliphatic diisocyanate compound is preferably one or more of ethylene diisocyanate, 2,2,4-trimethylhexamethylene diisocyanate and 1,6-hexamethylene diisocyanate. The cycloaliphatic diisocyanate compound is preferably one or more of 1,4-cyclohexane diisocyanate, 4,4'-dicyclohexylmethane diisocyanate, isophorone diisocyanate and norbornane diisocyanate.

[0049] The polyol, if not particularly limited, can be a compound known in the art of polyurethane, such as a polyether polyol and / or a polyester polyol. Preferably, the polyol is one or more of polytetramethylene ether glycol, polyethylene glycol, polypropylene glycol, polybutylene glycol, ethylene adipate and butylene adipate, or a copolymer formed by two or more of the above six substances.

[0050] The type of the prepolymer is preferably Adiprene ®L325, Adiprene ® LF750 and Adiprene ® one or more of the group consisting of LF700D.

[0051] The curing agent, which is not particularly limited, can be a compound known in the polyurethane field, for example, can be one or more of a polyol, a polyamine, and an alcohol amine, wherein the polyamine is a diamine and other polyfunctional amines. Preferably, the curing agent is one or more of 4,4'-methylene-bis-o-chloroaniline, 4,4'-methylenebis(3-chloro-2,6-diethyl aniline), dimethylthiuram disulfide, di-p-aminobenzoic acid-1,3-propanediyl diester, diethyltoluene diamine, 5-tert-amyl-2,4- and 3-tert-amyl-2,6-toluene diamine, and chlorotoluene diamine. More preferably, the curing agent is preferably MOCA and / or MCDEA, the MOCA being 3,3-dichloro-4,4-diaminodiphenyl methane, and the MCDEA being 4,4-methylenebis(3-chloro-2,6-diethyl aniline).

[0052] The polishing layer contains hollow microspheres, which are uniformly dispersed in the polishing layer. The hollow microspheres have a capsule structure of a polyacrylonitrile or polyacrylonitrile copolymer outer wall. More preferably, the hollow microspheres are of the Expancel series of hollow microspheres or the Matsumoto Micropearl F series. Further more preferably, the hollow microspheres are of the Expancel DE20d42 series. ® 551 DE20d42. The hollow microspheres are controlled to be uniformly distributed in the polishing layer in different regions at a wt% content.

[0053] The different hardness, density, compressibility, and other physical parameters of the polishing layer are controlled by the prepolymers of different components, the content of the curing agent, and the content of the microspheres. The composition is cast into a mold to form a cylinder, the cylinder is then sliced to obtain a thin sheet, and then grooving is performed on the thin sheet to obtain a polishing layer with a groove pattern, and the polishing layer is prepared.

[0054] As the cushion layer, for example, fibrous nonwoven fabrics such as polyester nonwoven fabric, nylon nonwoven fabric, and acrylic nonwoven fabric; resin-impregnated nonwoven fabrics such as polyester nonwoven fabric impregnated with polyurethane; polymeric resin foams such as polyurethane foam and polyethylene foam; rubbery resins such as butadiene rubber and isoprene rubber; and photosensitive resins can be listed.

[0055] The density, hardness, and compressibility of the cushion layer can be adjusted by using different nonwoven fabrics and polyurethane DMF solutions with different viscosities. After impregnation for a certain period of time, the TPU is molded and attached to the nonwoven fabric by solution exchange through a coagulation bath with low-concentration DMF, then washed in a water washing tank with clean water to remove the solvent, and then dried and molded in a tunnel oven at 150°C, and finally polished to the desired thickness.

[0056] <Polishing apparatus>

[0057] The second aspect of the present application provides a polishing apparatus having a polishing pad in contact with a workpiece to be polished, the polishing pad being the polishing pad according to the first aspect of the present application.

[0058] <Method for manufacturing semiconductor device>

[0059] The third aspect of the present application provides a method for manufacturing a semiconductor device, comprising a step of polishing a surface of a semiconductor wafer using a polishing pad, the polishing pad being the polishing pad according to the first aspect of the present application.

[0060] The above and other advantages of the present application will become more apparent by describing in detail the following embodiments thereof with reference to the attached drawings, in which:

[0061] Explanation of the example codes:

[0062] R: radius of the polishing pad, unit: mm;

[0063] R0: radius of the central margin area, unit: mm;

[0064] R1: width of the first annular polishing unit group, unit: mm;

[0065] R2: width of the second annular polishing unit group, unit: mm;

[0066] R3: width of the third annular polishing unit group, unit: mm;

[0067] e: width of the edge margin area, unit: mm;

[0068] W1: width of the annular groove on the first annular polishing unit group, unit: mm;

[0069] D1: distance between adjacent annular grooves on the first annular polishing unit group, unit: mm;

[0070] H1: depth of the annular groove on the first annular polishing unit group, unit: mm;

[0071] RS1: polishing area ratio of the first annular polishing unit group;

[0072] W2: width of the annular groove on the second annular polishing unit group, unit: mm;

[0073] D2: distance between adjacent annular grooves on the second annular polishing unit group, unit: mm;

[0074] H2: depth of the annular groove on the second annular polishing unit group, unit: mm;

[0075] RS2: ratio of polishing area of the second annular polishing unit group;

[0076] W3: width of the annular groove on the third annular polishing unit group, unit: mm;

[0077] D3: distance between adjacent annular grooves on the third annular polishing unit group, unit: mm;

[0078] H3: depth of the annular groove on the third annular polishing unit group, unit: mm;

[0079] RS3: ratio of polishing area of the third annular polishing unit group;

[0080] In Examples 1-12 and Comparative Examples 1-4, the polishing pad radius R is 387.35 mm, and the polishing layer thickness is 2.032 mm. The polishing pad in Examples 1-12 and Comparative Examples 1-4 comprises a polishing layer and a buffer layer, wherein the polishing layer is a polyurethane material prepared by reacting an isocyanate and a polyol to obtain an isocyanate-terminated prepolymer, and then reacting the prepolymer with a curing agent and hollow microspheres. The polishing pad uses a polyurethane-impregnated non-woven fabric as the buffer layer. The preparation method of the polishing pad is as follows:

[0081] (1) Preparation of the polishing layer: 23.0 parts by mass of TDI (toluene diisocyanate), 46.3 parts by mass of PTMEG (polytetramethylene ether glycol, molecular weight 701.0), and 30.7 parts by mass of MOCA (3,3'-dichloro-4,4'-diaminodiphenyl methane) are used. The microspheres used are Expancel 551DE40D42 microspheres manufactured by AkzoNobel, and the mass of the microspheres accounts for 1.2% of the total mass of the polishing layer. The above materials are added to a pouring head, mixed rapidly at a mixing rate of 5000 rpm, poured into a mold to form a cylinder, then the cylinder is sliced to obtain a thin sheet, and finally the sheet is grooved to obtain a polishing layer with a groove pattern.

[0082] (2) The polishing layer obtained in step (1) and the buffer layer of polyurethane-impregnated non-woven fabric are attached to obtain a polishing pad.

[0083] The preparation method of the polishing pad in the embodiments of the present application is not limited to the present application, and the polishing pads obtained by other methods known in the art are also suitable for the present application.

[0084] The groove structure parameters on the polishing surface of the polishing pads in Examples 1-12 and Comparative Examples 1-4 are shown in Table 1 and Table 1-continued:

[0085] Table 1 Groove structure parameters on the polishing surface of the polishing pads in Examples 1-12 and Comparative Examples 1-4

[0086]

[0087] Table 1 (Continued) Groove structure parameters on the polishing surface of the polishing pads of Examples 1 to 12 and Comparative Examples 1 to 4

[0088]

[0089] Evaluation method of the polishing pad:

[0090] Polishing conditions: In the polishing, a silica slurry (SS25E, manufactured by CABOT) was added as a slurry at a flow rate of 250 ml / min. The polishing load was set to 3.5 psi, the polishing table rotation speed was set to 110 rpm, and the wafer rotation speed was set to 108 rpm. At the time of the test, the average polishing rate, the polishing rate non-uniformity, and the number of scratches were measured as the quality characteristics of the polishing pad.

[0091] Average polishing rate: Under the above conditions, a thermal oxide film having a thickness of 8500 A was deposited on a 12-inch test wafer and polished, and the average polishing rate was calculated from the wear loss in 1 minute, in units of (A / min).

[0092] Polishing rate non-uniformity: The thickness of the polishing object was measured before and after the polishing test. 49 positions on the surface of the polishing object were selected in advance for measurement, and the standard deviation (STDEV) and the average (AVERAGE) of the polishing rates at the selected positions were calculated. The polishing rate non-uniformity can be calculated using the following equation (1).

[0093] Polishing rate non-uniformity = 100% * standard deviation / average Equation (1)

[0094] Table 2 is the evaluation of the polishing performance, i.e., the polishing effect, of the polishing pads of Examples 1 to 12 and Comparative Examples 1 to 4.

[0095] Table 2 Polishing performance of the polishing pads of Examples 1 to 12 and Comparative Examples 1 to 4

[0096]

Claims

1. A polishing pad, characterized in that, The polishing pad has a polishing surface, and from the center of the polishing surface outward to the outer periphery, at least a first annular grinding unit group, a second annular grinding unit group, and a third annular grinding unit group are sequentially arranged on the polishing surface. The grinding area ratio of the second annular grinding unit group is greater than that of the first annular grinding unit group, and the grinding area ratio of the second annular grinding unit group is greater than that of the third annular grinding unit group. The width R2 of the second annular grinding unit group is equal to the diameter D of the material being ground. W 0.33~0.67; The spacing between adjacent annular grooves in the first annular grinding unit group, D1, is less than the spacing between adjacent annular grooves in the second annular grinding unit group, D2, and the spacing between adjacent annular grooves in the third annular grinding unit group, D3, is less than the spacing between adjacent annular grooves in the second annular grinding unit group, wherein D1 and D3 are equal or unequal.

2. The polishing pad according to claim 1, characterized in that, The grinding area ratio of the first, second, and third annular grinding unit groups is 0.60 to 0.95; wherein the grinding area ratio of the first and third annular grinding unit groups is equal or unequal.

3. The polishing pad according to claim 1, characterized in that, The grinding area ratio of the first annular grinding unit group, the second annular grinding unit group, and the third annular grinding unit group is 0.60~0.

9. The grinding area ratios of the first and third annular grinding unit groups are equal or unequal.

4. The polishing pad according to claim 1, characterized in that, The grinding area ratio of the first annular grinding unit group, the second annular grinding unit group, and the third annular grinding unit group is 0.70~0.

9. The grinding area ratios of the first and third annular grinding unit groups are equal or unequal.

5. The polishing pad according to claim 1, characterized in that, The width R2 of the second annular grinding unit group is equal to the diameter D of the material being ground. W 0.55~0.

65.

6. The polishing pad according to claim 1, characterized in that, The value of D2 is 1.2 to 3 times that of D1; the value of D2 is 1.2 to 3 times that of D3.

7. The polishing pad according to claim 1, characterized in that, D2 is 1.5 to 2.5 times D1; ​​D2 is 1.5 to 2.5 times D3.

8. The polishing pad according to claim 1, characterized in that, D2 is twice D1; D2 is twice D3.

9. The polishing pad according to claim 1, characterized in that, The depth of the annular groove in the first annular grinding unit group is denoted as H1, the depth of the annular groove in the second annular grinding unit group is denoted as H2, and the depth of the annular groove in the third annular grinding unit group is denoted as H3; wherein, H1, H2 and H3 are 0.02 to 0.8 times the thickness of the polishing layer.

10. The polishing pad according to claim 1, characterized in that, The depth of the annular groove in the first annular grinding unit group is denoted as H1, the depth of the annular groove in the second annular grinding unit group is denoted as H2, and the depth of the annular groove in the third annular grinding unit group is denoted as H3; wherein, H1, H2 and H3 are 0.15 to 0.6 times the thickness of the polishing layer.

11. The polishing pad according to claim 9, characterized in that, H1, H2, and H3 may be equal or unequal.

12. The polishing pad according to claim 9, characterized in that, H1 > H2, and / or H3 > H2.

13. The polishing pad according to any one of claims 1-12, characterized in that, The polishing pad is used to polish the metal layer or oxide layer, wherein the metal layer includes any one of copper, tungsten, and aluminum.

14. A grinding apparatus, characterized in that, A polishing pad having contact with the workpiece being polished, wherein the polishing pad is the polishing pad according to any one of claims 1-13.

15. A method for manufacturing a semiconductor device, characterized in that, The process includes grinding the surface of a semiconductor wafer using a polishing pad, wherein the polishing pad is the polishing pad described in any one of claims 1-13.

Images