Polishing pad and manufacturing method for semiconductor device

Abstract

A polishing pad and a manufacturing method for a semiconductor device. The thermal conductivity of a polishing layer (20) is 0.04 W / (m·K) to 0.075 W / (m·K), and the ratio of the density SG1 of any point in the diameter direction to the minimum density SG0 of the polishing layer in the diameter direction is 1.002-1.096; one or a combination of more of trenches are formed on the surface of the polishing layer, and the ratio, i.e., (V0-V) / V0, of a difference value between the volume V0 of the polishing layer before the trenches are formed and the volume V of the polishing layer after the trenches are formed to the volume V0 of the polishing layer before the trenches are formed is 0.02-0.19. According to the manufacturing method for the semiconductor device, the polishing pad is used to grind the surface of a semiconductor device wafer as much as possible. In the polishing process of the polishing pad, the non-uniformity of a polishing rate is small, and the surface of the wafer has fewer defects.

Description

Polishing pad and method for manufacturing semiconductor device

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority with application date of September 5, 2023, application number 202311141044.1, and title “Polishing Pad and Method for Manufacturing Semiconductor Device”. The entire contents of the above Chinese patent application are hereby incorporated into this application by introduction. Technical Field

[0003] The present invention relates to the technical field of polishing for chemical mechanical planarization treatment, and in particular to a polishing pad and a method for manufacturing a semiconductor device. Background Art

[0004] CMP technology involves placing the workpiece surface facing downward and applying pressure to a polishing pad. In a flowing polishing medium (a mixture of nanoparticles, a chemical oxidant, and a liquid medium), the relative motion of the polishing pad and workpiece results in mechanical abrasion by the nanoparticles and chemical etching by the oxidant, ultimately removing material from the workpiece surface, thereby achieving global planarization. As the semiconductor industry evolves along the curve of Moore's Law, processing trends are shifting toward higher current densities, higher clock frequencies, and more interconnect layers. Due to shrinking chip geometries and the reduced depth of focus of optical lithography equipment, chip surface flatness with acceptable resolution is required to reach the nanometer level. While traditional planarization technologies such as selective deposition, sputtered glass SOG, low-pressure CVD, plasma-enhanced CVD, bias sputtering, post-sputter etch for structures, thermal reflow, and deposition-etch-deposition methods can produce "smooth" surfaces, they are limited to local planarization techniques and cannot achieve global planarization. It is generally believed internationally that when the device feature size is below 0.35μm, global planarization must be performed to ensure the accuracy and resolution of lithography-affected transfer. CMP technology is currently recognized internationally as the only technology that can provide global planarization. The yield of CMP seriously affects the yield of chips.

[0005] As people demand devices with higher operating speeds, lower leakage currents and less energy consumption, the manufacturing of semiconductor devices has become increasingly complex. This means that the devices require geometric structures with finer features and more metallization levels. These increasingly stringent design requirements have prompted people to use smaller line spacing. As the devices become smaller and more complex, the requirements for CMP technology become higher. In addition, as the feature size of integrated circuits decreases, defects caused by CMP, such as scratches, and grinding rate non-uniformity become bigger problems.

[0006] Summary of the Invention

[0007] The object of the present invention is to provide a polishing pad with excellent comprehensive polishing performance.

[0008] According to a first aspect of the present invention, a polishing pad is provided, comprising a polishing layer, wherein the polishing layer is a closed-cell elastomer formed from a polyurethane substrate having continuously separated pores, wherein the thermal conductivity of the polishing layer is between 0.04 W / (m·K) and 0.075 W / (m·K), and the ratio of the density SG1 of the polishing layer at any point along the diameter to the minimum density SG0 of the polishing layer along the diameter is between 1.002 and 1.096. The polishing layer is grooved on its surface, wherein the groove shapes include: concentric circular grooves, radial grooves, arc grooves, XY grid grooves, and dot matrix perforated grooves, and the difference between the volume V0 of the polishing layer before grooves and the volume V after grooves and the ratio of the volume V0 of the polishing layer before grooves (V0-V) / V0 are between 0.02 and 0.19.

[0009] Preferably, the thermal conductivity of the polishing layer is between 0.048 W / (m·K) and 0.065 W / (m·K);

[0010] Furthermore, the density of the polishing layer is between 0.4 g / cm 3 ~0.73g / cm 3 between;

[0011] Preferably, the density of the polishing layer is between 0.4 g / cm 3 ~0.65g / cm 3 between;

[0012] Furthermore, the tensile strength of the polishing layer is between 2 MPa and 18 MPa;

[0013] Preferably, the tensile strength of the polishing layer is between 7 MPa and 14.5 MPa;

[0014] Furthermore, the ratio of the density SG1 of the polishing layer at any point along the diameter direction to the minimum density SG0 of the polishing layer along the diameter direction is between 1.002 and 1.075;

[0015] Furthermore, the ratio of the difference between the volume V0 of the polishing layer before grooving and the volume V after grooving to the volume V0 of the polishing layer before grooving (V0-V) / V0 is between 0.02 and 0.145;

[0016] Furthermore, the polyurethane substrate is obtained by reacting a multifunctional isocyanate, a polyol and a curing agent;

[0017] The polyfunctional isocyanate comprises one or more combinations 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, m-xylylene diisocyanate, ethylene diisocyanate, 2,2,4-trimethylhexamethylene diisocyanate, 1,6-hexamethylene diisocyanate, 1,4-cyclohexane diisocyanate, 4,4'-dicyclohexylmethane diisocyanate, isophorone diisocyanate, and norbornane diisocyanate;

[0018] The polyol comprises one or more combinations of polytetramethylene ether glycol, polyethylene glycol, polypropylene glycol, ethylene glycol, butanediol, diethylene glycol, neopentyl glycol, 2-methyl-1,3-propanediol, hexanediol, 3-methyl-1,5-pentanediol, 1,4-cyclohexanedimethanol, homopolymers and / or copolymers of ethylene oxide and propylene oxide;

[0019] Preferably, the multifunctional isocyanate comprises one or more combinations of toluene diisocyanate, diphenylmethane diisocyanate, and 4,4'-dicyclohexylmethane diisocyanate, and the polyol comprises one or a combination of polytetramethylene ether glycol, diethylene glycol, butanediol, a homopolymer and / or copolymer of ethylene oxide and propylene oxide;

[0020] Furthermore, it includes a buffer layer, wherein the thermal conductivity of the buffer layer is between 0.06W / (m·K) and 0.09W / (m·K);

[0021] Furthermore, the ratio of the thermal conductivity of the polishing layer to that of the buffer layer is between 0.5 and 1.2.

[0022] A second aspect of the present invention provides a polishing pad, comprising a polishing layer, a buffer layer, an adhesive layer, and a backing layer, wherein the thermal conductivity of the polishing pad is between 0.04 W / (m·K) and 0.09 W / (m·K);

[0023] Furthermore, the polishing layer is a closed-cell elastomer formed from a polyurethane substrate having continuous pore separations, the thermal conductivity of the polishing layer is between 0.04W / (m·K) and 0.075W / (m·K), the ratio of the density SG1 of the polishing layer at any point along the diameter direction to the minimum density SG0 of the polishing layer along the diameter direction is between 1.002 and 1.096, the surface of the polishing layer is engraved with grooves, and the groove shapes include: one or more combinations of concentric grooves, radial grooves, arc grooves, XY grid grooves, and dot matrix punching grooves, and the difference between the volume V0 of the polishing layer before groove engraving and the volume V after groove engraving and the ratio of the volume V0 of the polishing layer before groove engraving (V0-V) / V0 are between 0.02 and 0.19.

[0024] The third and fourth aspects of the present invention provide a method for manufacturing a semiconductor device, comprising a step of grinding the surface of a semiconductor device wafer using a polishing pad, wherein the polishing pad is the polishing pad described in the first and second aspects above.

[0025] Beneficial effects: The present invention controls the thermal conductivity of the polishing layer, the ratio of the density of any point along the diameter of the polishing layer to the minimum density of the polishing layer along the diameter, and the difference between the volume of the polishing layer before grooving and the volume after grooving and the ratio of the volume of the polishing layer before grooving within a certain range. The polishing pad prepared thereby has lower grinding rate non-uniformity, lower defects, and higher comprehensive polishing performance; and by controlling the thermal conductivity of the buffer layer and the ratio of the thermal conductivity of the polishing layer to the thermal conductivity of the buffer layer within a certain range, and when used in combination with the polishing layer in the present application, the comprehensive polishing performance can be further improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0027] FIG1 is a schematic diagram of a polishing operation process performed by a polishing pad according to an embodiment of the present invention;

[0028] FIG2 is a schematic diagram of a polishing pad provided in an embodiment of the present invention;

[0029] FIG3 is a schematic diagram of density sampling at various points along the diameter direction of the polishing pad tested in the present invention;

[0030] FIG4 is a schematic diagram of concentric circular grooves in an embodiment of the present invention;

[0031] FIG5 is a schematic diagram of a concentric circle and radial line composite groove according to an embodiment of the present invention;

[0032] FIG6 is a schematic diagram of an XY grid groove according to an embodiment of the present invention;

[0033] FIG7 is a schematic diagram of an arc-shaped groove in an embodiment of the present invention;

[0034] FIG8 is a schematic diagram of a dot matrix punching groove in an embodiment of the present invention;

[0035] FIG9 is a schematic diagram of an arc-shaped groove in a comparative example of the present invention;

[0036] FIG10 is a schematic diagram of an XY grid groove in a comparative example of the present invention;

[0037] FIG11 is a schematic diagram of an XY grid groove with an included angle in a comparative example of the present invention.

[0038] 1- Material to be polished; 2- Polishing pad; 3- Polishing machine; 4- Bracket; 5- Polishing liquid; 20- Polishing layer; 22- Buffer layer; 21- Adhesive layer; 23- Adhesive layer. DETAILED DESCRIPTION

[0039] The embodiments of the present invention will be described in detail below with reference to the examples. However, it will be understood by those skilled in the art that the following examples are intended only to illustrate the present invention and should not be construed as limiting the scope of the invention. Where specific conditions are not specified in the examples, the experiments were carried out under conventional conditions or conditions recommended by the manufacturer. Where the manufacturer of the reagents or instruments is not specified, all are conventional products that can be purchased commercially.

[0040] <Method for Manufacturing Semiconductor Device>

[0041] Semiconductor devices are manufactured by polishing the surface of a semiconductor wafer using a polishing pad. A semiconductor wafer generally refers to a wafer with wiring metal and an oxide film stacked on a silicon wafer. The manufacturing method of the semiconductor device of the present invention includes a process of polishing the surface of a semiconductor wafer using a polishing pad, and there is no special restriction on the polishing device.

[0042] For example, a polishing device as shown in FIG1 is used, which comprises a polishing table 3 supporting a polishing pad 2, a support 4 supporting a material to be polished - a semiconductor wafer 1 and a backing material for uniformly pressurizing the wafer, and a supply mechanism for a polishing liquid 5. The polishing pad 2 is mounted on the polishing table 3, for example, by adhesion of a backing adhesive layer. The polishing table 3 and the support 4 are configured so that the polishing pad 2 and the semiconductor wafer 1 supported by each are opposite to each other, and each has a rotation axis. In addition, a pressurizing mechanism for pressing the semiconductor wafer 1 onto the polishing pad 2 is provided on one side of the support 4. During polishing, the polishing table 3 and the support 4 are rotated, and the semiconductor wafer 1 is pressed onto the polishing pad 2, while polishing is performed while supplying slurry. There are no particular restrictions on the slurry flow rate, polishing load, polishing table rotation speed, and wafer rotation speed, and they can be adjusted appropriately.

[0043] Thus, the protruding parts of the surface of the semiconductor wafer 1 are removed and polished to a flat state. Thereafter, semiconductor devices are manufactured through dicing, bonding, packaging, etc., and the semiconductor devices are used in arithmetic processing devices, storage devices, etc.

[0044] <Polishing layer>

[0045] Thermal conductivity

[0046] The polishing layer in the embodiment of the present invention is a closed-cell elastomer formed by a polyurethane substrate having continuous pore separation, and the thermal conductivity is between 0.04W / (m·K) and 0.075W / (m·K).

[0047] Preferably, the thermal conductivity of the polishing layer in the present invention is between 0.048 W / (m·K) and 0.065 W / (m·K);

[0048] By controlling the thermal conductivity of the polishing layer, the heat transfer of the polishing layer during the polishing process can be adjusted to achieve better polishing performance.

[0049] Density uniformity

[0050] In the embodiment of the present invention, the ratio of the density SG1 of the polishing layer at any point along the diameter direction to the minimum density SG0 of the polishing layer along the diameter direction is between 1.002 and 1.096 (the density SG1 at any point along the diameter direction does not include the minimum density SG0). Due to problems such as uneven heat dissipation during the casting and curing process of the polyurethane substrate, its density in the radial direction may be uneven. Through research, the present invention has found that by controlling the formula, the ratio of the density at any point along the diameter direction of the polishing layer to the minimum density in the radial direction can be controlled within a certain range, thereby obtaining good polishing performance.

[0051] The method for measuring the radial density of the polishing layer in the embodiment of the present invention can be selected using conventional testing methods in the field. As an example of a radial testing method, the polishing layer can be punched into test samples of a certain size and a certain shape at a certain distance along the radial direction of the polishing layer, wherein the shape of the test sample can be selected as any shape. In the present invention, it is preferred to use one of a circle or a square. Particularly preferably, as shown in Figure 3, the shape of the test sample is a square. The size of the test sample can be selected as any size. The sampling number of the test sample can be determined according to the size of the test sample. The sampling number can be one of 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, and 30. Preferably, an odd number of samples can be selected.

[0052] In the embodiment of the present invention, the density values ​​of multiple test samples in the radial direction of the polishing layer are tested to reflect the difference in the radial density of the polishing layer, and the minimum density SG0 is selected as the denominator and the density SG1 of other test samples is selected as the numerator, and the ratio of the two is controlled to be between 1.002 and 1.096. Preferably, when the ratio of the two is controlled to be between 1.002 and 1.075, the uniformity of the radial density of the polishing layer can be controlled to obtain an excellent polishing effect.

[0053] groove

[0054] In an embodiment of the present invention, the polishing layer may be provided with grooves as is conventional in the art, and the grooves are used to receive the polishing liquid during the polishing process. The grooves may be obtained by processing after the polishing pad is formed. The provision of the grooves can ensure the smooth discharge and flow of the polishing liquid used during the polishing process. Preferably, the grooves are one or more combinations of concentric grooves, radial grooves, XY grid grooves, arc grooves, lattice punched grooves, spiral grooves, and hexagonal grooves. Particularly preferably, the grooves are one or more combinations of concentric grooves, radial grooves, XY grid grooves, arc grooves, and lattice punched grooves. The cross-section of the groove is one or more of a straight sidewall rectangle, a "V" shape, a "U" shape, and a zigzag shape. Preferably, the cross-section of the groove is a straight sidewall rectangle.

[0055] The groove volume of the polishing layer can be expressed as: the difference between the volume V0 of the polishing layer before grooving and the volume V after grooving; when the ratio of the volume V0 to the volume V0 of the polishing layer before grooving is between 0.02 and 0.19, the polishing pad exhibits a higher removal rate and lower defects. In the present invention, preferably, (V0-V) / V0 is between 0.02 and 0.145.

[0056] In the embodiment of the present invention, the volume V0 of the polishing layer before grooving and the volume V after grooving can be obtained by conventional methods in the field without special limitation. They can be obtained by calculation based on the actual parameters of the groove, or by calculation after fitting using conventional design software in the field.

[0057] The present invention has found that by simultaneously controlling the thermal conductivity, density uniformity, specific groove shape and groove volume of the polishing layer within a certain range, the polishing pad prepared exhibits excellent comprehensive polishing performance.

[0058] The density of the polishing layer in the embodiment of the present invention is between 0.4 g / cm 3 ~0.73g / cm 3 The tensile strength of the polishing layer is between 2MPa and 18MPa.

[0059] Preferably, the density of the polishing layer in the present invention is between 0.5 g / cm 3 ~0.65g / cm 3 between;

[0060] Preferably, the tensile strength of the various polishing layers of the present invention is between 7 MPa and 14.5 MPa;

[0061] As a preferred solution, when the thermal conductivity, density uniformity and groove volume of the polishing layer are controlled within a certain range, the density is controlled within a lower range, that is, the density is less than 0.65 g / cm 3 When the polishing pad is prepared, the comprehensive polishing performance will be further improved; in the embodiment of the present invention, the comprehensive polishing performance depends on the grinding rate non-uniformity (NU) and the number of defects. Maintaining a low grinding rate non-uniformity (NU) and a low number of defects can achieve a higher comprehensive polishing performance.

[0062] In the embodiment of the present invention, the polishing layer comprises a polyurethane substrate, and the polyurethane substrate is obtained by reacting multifunctional isocyanate, polyol and curing agent.

[0063] Polyfunctional isocyanate

[0064] In the embodiment of the present invention, the polyfunctional isocyanate includes but is not limited to one or more combinations of aromatic isocyanates or aliphatic isocyanates. It is preferred to use more than 80 mol% of aromatic isocyanates, more preferably more than 95 mol% of aromatic isocyanates, and particularly preferably 100 mol% of aromatic isocyanates.

[0065] The aromatic isocyanate includes one or more combinations of toluene diisocyanate, diphenylmethane diisocyanate, 1,5-naphthalene diisocyanate, p-phenylene diisocyanate, m-phenylene diisocyanate, p-xylylene diisocyanate, and m-xylylene diisocyanate.

[0066] The aliphatic isocyanate includes one or more combinations of ethylene diisocyanate, 2,2,4-trimethylhexamethylene diisocyanate, 1,6-hexamethylene diisocyanate, 1,4-cyclohexane diisocyanate, 4,4'-dicyclohexylmethane diisocyanate, isophorone diisocyanate, and norbornane diisocyanate.

[0067] In the embodiment of the present invention, considering the reactivity and physical properties of the polishing pad, one or more combinations of toluene diisocyanate, diphenylmethane diisocyanate, and 4,4'-dicyclohexylmethane diisocyanate are preferably used.

[0068] In the embodiments of the present invention, considering the reactivity and physical properties of the polishing pad, it is particularly preferred to use one of toluene diisocyanate and 4,4-dicyclohexylmethane diisocyanate or a combination of the two.

[0069] polyols

[0070] In the embodiment of the present invention, the polyol may include a high molecular weight diol based on polyether, wherein the high molecular weight diol based on polyether includes but is not limited to polytetramethylene ether glycol (PTMEG), polyethylene glycol (PEG), polypropylene glycol (PPG), and one or more combinations of polytetramethylene ether glycol-polyethylene glycol, polytetramethylene ether glycol-polypropylene glycol, polyethylene glycol-polypropylene glycol, ethylene oxide and propylene oxide homopolymers and / or copolymers, or ethylene glycol, propylene glycol, butanediol or an initiator having two hydroxyl groups and the above three small molecule diols to form a high molecular weight polyol, or multiple combinations.

[0071] In the embodiment of the present invention, the polyol may include a small molecule diol, wherein the small molecule includes but is not limited to one or more combinations of ethylene glycol, butanediol, diethylene glycol, neopentyl glycol, 2-methyl-1,3-propanediol, hexanediol, 3-methyl-1,5-pentanediol, and 1,4-cyclohexanedimethanol.

[0072] In the embodiment of the present invention, the polyol composition may further include a polyester-based polyol, wherein the polyester-based polyol is obtained by a condensation reaction of a diol or a diol / phenol with a dibasic acid, wherein the diol includes one or more combinations of ethylene glycol, 1,3-butanediol, 1,4-butanediol, diethylene glycol, neopentyl glycol, 2-methyl-1,3-propanediol, hexanediol, 3-methyl-1,5-pentanediol, and 1,4-cyclohexanedimethanol. Preferably, the diol includes one or a combination of 1,4-butanediol and hexanediol; the diol / phenol is hydroquinone, resorcinol, naphthalene diol, bisphenol A, bisphenol S, terephthalic acid, One or more combinations of isophthalic acid, o-phthalic acid, 2,5-furan dimethanol, p-phthalic acid or diphenyl ether diphenol. Preferably, the diol / phenol is one or a combination of hydroquinone and p-phthalic acid; the dibasic acid is one or more combinations of succinic acid, adipic acid, azelaic acid and sebacic acid.

[0073] In the embodiment of the present invention, considering the reactivity and physical properties of the polishing pad, one or more combinations of polytetramethylene ether glycol (PTMEG), diethylene glycol, butanediol, or homopolymers and / or copolymers of ethylene oxide and propylene oxide are preferably used.

[0074] In the embodiments of the present invention, considering the reactivity and physical properties of the polishing pad, it is particularly preferred to use one of polytetramethylene ether glycol (PTMEG) and diethylene glycol or a combination of the two.

[0075] curing agent

[0076] In the embodiment of the present invention, the curing agent is selected from one or more combinations of aromatic bifunctional curing agents or polyol curing agents. The present invention has no particular limitation on the aromatic bifunctional curing agent or polyol curing agent, and it can be any suitable aromatic bifunctional curing agent or polyol curing agent in the art.

[0077] Examples of aromatic bifunctional curing agents that can be used in embodiments of the present invention include diethyltoluenediamine (DETDA), N,N'-dialkyldiaminodiphenylmethane, 3,5-diethyl-2,4-toluenediamine and its isomers (e.g., 3,5-diethyl-2,6-toluenediamine), 3,5-dimethylthio-2,4-toluenediamine and its isomers, 4,4'-methylene-bis-(2-chloroaniline) (MOCA), 4,4'-bis-(sec-butylamino)-diphenylmethane, 1,4-bis-(sec-butylamino)-benzene, 4,4'-methylene-bis-(2-chloroaniline), 4,4'-dimethylthio-2,4-toluenediamine, ... -methylene-bis-(3-chloro-2,6-diethylaniline) (M-CDEA), polyoxytetramethylene-bis-p-aminobenzoate; p,p'-methylenedianiline (MDA); m-phenylenediamine (MPDA); 4,4'-methylene-bis-(2,6-diethylaniline) (MDEA), 4,4'-methylene-bis-(2,3-dichloroaniline) (MDCA), 4,4'-diamino-3,3'-diethyl-5,5'-dimethyldiphenylmethane, 2,2',3,3'-tetrachlorodiaminodiphenylmethane, propylene glycol-bis-p-aminobenzoate or one or more combinations thereof.

[0078] Preferably, the aromatic bifunctional curing agent comprises a combination of two or more of 4,4'-methylene-bis-(2-chloroaniline) (MOCA), 4,4'-bis-(sec-butylamino)-diphenylmethane, 4,4'-methylene-bis-(3-chloro-2,6-diethylaniline) (M-CDEA), and polyoxytetramethylene-bis-p-aminobenzoate. Considering the unique chemical structure of MOCA, in order to ensure a suitable operating time during polishing pad preparation and the resulting polishing pad has good polishing performance, the aromatic bifunctional curing agent preferably comprises one or a combination of 4,4'-methylene-bis-(2-chloroaniline) (MOCA) and 4,4'-methylene-bis-(3-chloro-2,6-diethylaniline) (M-CDEA); particularly preferably, the aromatic bifunctional curing agent comprises 4,4'-methylene-bis-(2-chloroaniline) (MOCA).

[0079] The polyurethane substrate in the embodiment of the present invention can be manufactured using well-known polyurethane forming technologies such as a melt method and a solution method, or can be manufactured by any conventional method such as a prepolymer method and a one-shot injection method. The prepolymer method is to first synthesize an isocyanate-terminated prepolymer from a polyfunctional isocyanate and a polyol composition component and react it with a polyamine composition; the one-shot injection method is to react the polyfunctional isocyanate, the polyol composition, and the polyamine composition in one step; in the present invention, the prepolymer method is preferably used to synthesize the polyurethane substrate.

[0080] The isocyanate-terminated prepolymer can be obtained by reacting the multifunctional isocyanate with the polyol composition, or by purchasing a commercially available prepolymer product.

[0081] Commercially available isocyanate-terminated prepolymers include, but are not limited to, any one or more combinations of the series of prepolymers produced by Chemtura: LF800A, LF900A, LF910A, LF930A, LF931A, LF939A, LF950A, LF952A, LF600D, LF601D, LF650D, L42, L325, L100, L150, L167, L200, L275, L300, L310, L367, L480, L500, LF667D, LF700D, LF750D, LF751D, LF752D, LF753D, LFG963A, LFG964A, and LFG740D.

[0082] Hollow microsphere polymer

[0083] In the process of preparing the polishing layer, the hollow microsphere polymer is usually evenly dispersed in the polishing layer, so as to adjust the polishing effect of the polishing layer.

[0084] The term "hollow microsphere polymer" in the embodiments of the present invention refers to expandable hollow polymer microspheres that expand moderately during the curing process due to the temperature increase caused by the exothermic reaction. By adjusting the distribution (e.g., density) of the hollow microsphere polymer in the polyurethane polishing layer and adjusting the particle size of the hollow microsphere polymer, the polishing performance of the polishing layer can be further adjusted. Preferably, the hollow microsphere polymer is dispersed in the polishing layer so that the final porosity of the polishing layer is 10% to 65%.

[0085] Preferably, the hollow microsphere polymer includes but is not limited to a sac-like structure having an outer wall of polyacrylonitrile and a polyacrylonitrile copolymer, and can be purchased from any of Akzo Nobel, Matsumoto Oil and Fat Pharmaceutical Co., Ltd. or Sekisui Chemical Co., Ltd. Microspheres or microbeads, particularly preferably, in the embodiment of the present invention, Akzo Nobel hollow microspheres or Matsumoto microbeads F series are selected.

[0086] <Buffer layer>

[0087] In an embodiment of the present invention, a buffer layer is provided on the back of the polishing layer. The buffer layer can reduce the impact applied to the polishing pad during the polishing process. The elastic modulus of the buffer layer is higher than that of the polishing layer. The buffer layer is a necessary layer to take into account both planarity and uniformity in a trade-off relationship in CMP. Planarity refers to the flatness of the polished pattern portion of the polished material having tiny bumps and depressions generated during pattern formation, and uniformity refers to the uniformity of the entire polished material. The planarity is improved by the characteristics of the polishing layer, and the uniformity is improved by the characteristics of the buffer layer.

[0088] In the embodiment of the present invention, the thermal conductivity of the buffer layer is between 0.06 W / (m·K) and 0.09 W / (m·K).

[0089] In the embodiments of the present invention, it is found that when the ratio of the thermal conductivity of the polishing layer to the buffer layer is within a certain range, the polishing pad exhibits good polishing performance. Preferably, the ratio of the polishing layer to the buffer layer is between 0.5 and 1.2.

[0090] In the embodiment of the present invention, the buffer layer has a thickness of 30 mil to 150 mil.

[0091] In the embodiment of the present invention, the buffer layer is a non-woven fabric coated with an impregnated material or a foamed resin, wherein the non-woven fabric coated with an impregnated material comprises a non-woven fabric impregnated with polyurethane, wherein the non-woven fabric impregnated with polyurethane is composed of fiber non-woven fabrics such as polyester non-woven fabric, nylon non-woven fabric, acrylic non-woven fabric and polyurethane resin: wherein the foamed resin comprises commonly used foamed resins such as polyurethane, polyethylene, polypropylene, polysulfone, polyvinyl chloride, polysilicone resin, etc., and the preferred buffer layer is one of the non-woven fabric impregnated with polyurethane or polyurethane foam resin or polypropylene foam resin in the non-woven fabric coated with an impregnated material.

[0092] <Polishing Pad>

[0093] The polishing pad in an embodiment of the present invention is shown in Figure 2, and includes a polishing layer 20, a buffer layer 22, an adhesive layer 21 and a back adhesive layer 23. The polishing pad in the present invention is arranged from top to bottom as a polishing layer 20, an adhesive layer 21, a buffer layer 22, and a back adhesive layer 23, wherein the adhesive layer 21 is used to bond the polishing layer 20 and the buffer layer 22, and the back adhesive layer 23 also includes a release film or release paper. When in use, the release film or release paper can be torn off to achieve the bonding of the polishing pad and the polishing machine.

[0094] In the present invention, excellent polishing performance is taken into consideration. When the thermal conductivity of the polishing pad in the embodiment of the present invention is controlled to be between 0.04W / (m·K) and 0.09W / (m·K), preferably, when the thermal conductivity of the polishing pad in the embodiment of the present invention is controlled to be between 0.045W / (m·K) and 0.083W / (m·K), the polishing pad exhibits excellent comprehensive polishing performance. The polishing pad can be composed of the polishing layer and buffer layer of the present invention, or can be composed of the polishing layer and buffer layer known in the art.

[0095] Example

[0096] The present invention will be further described below with reference to the schematic examples shown in the accompanying drawings. The advantages of the present invention in various aspects will become more apparent through the following description. The same figure marks in the drawings refer to the same components. The shapes and sizes of the components in the schematic drawings are for illustration only and cannot be recognized as reflecting the actual shape, size and absolute position.

[0097] Throughout the specification, unless otherwise specified, the terms used herein should be understood as commonly used in the art. Therefore, unless otherwise defined, all technical and scientific terms used herein have the same meaning as generally understood by those skilled in the art. If there is any conflict, the present specification takes precedence.

[0098] TDI: toluene diisocyanate;

[0099] HMDI: 4,4'-dicyclohexylmethane diisocyanate;

[0100] PTMEG: polytetramethylene ether glycol;

[0101] PPG: copolymer of ethylene oxide and propylene oxide;

[0102] MDI: diphenylmethane diisocyanate;

[0103] DEG: diethylene glycol;

[0104] MOCA: 4,4'-methylene-bis-(2-chloroaniline);

[0105] M-CDEA: 4,4'-methylene-bis-(3-chloro-2,6-diethylaniline);

[0106] Hollow microsphere polymer: Average particle size 40 μm, density 0.042 g / cm 3 , Average particle size 20 μm, density 0.07 g / cm 3 .

[0107] The above raw materials are all from bulk industrial products on the market, and manufacturers include BASF, Covestro, Wanhua Chemical, Suzhou Xiangyuan, Chizhou Tianci, Mitsui Chemicals, Mitsubishi Chemical, etc.

[0108] The following physical and chemical parameter determination methods and other parameter calculation methods are as follows:

[0109] Density of polishing layer

[0110] Calculate according to the following formula: SG = m / v = m / (π(d / 2)^2*h), where m is the weight of the polishing layer, d is the diameter of the polishing layer, and h is the thickness of the polishing layer.

[0111] Polishing layer / buffer layer / polishing pad thermal conductivity

[0112] Polishing layer sample preparation: Cut the polishing layer into thin slices with a thickness of 0.8 mm, or use a grinder to remove the uneven rubber layer and concave grooves on the polishing layer after groove engraving, and grind it into a uniform thickness of about 0.8 mm. Then use a circular die with a diameter of 4 cm to cut it to obtain a polishing layer test sample with a diameter of 4 cm and a thickness of 0.8 mm.

[0113] Buffer layer sample preparation: The original buffer layer sample is directly cut with a die cutter with a diameter of 4 cm to obtain a buffer layer test sample with original thickness and a diameter of 4 cm.

[0114] Polishing pad sample preparation: Grind away the grooves of the finished polishing pad with a grinder until the polishing layer thickness reaches about 0.8 cm. Alternatively, use a pressure-sensitive adhesive or hot-melt adhesive to bond the polishing layer and the buffer layer together, and then apply adhesive backing to one side of the buffer layer.

[0115] Use a DRL-Ⅲ thermal conductivity meter and a low-temperature constant temperature circulator, set the circulating refrigeration temperature to 5°C, take the polishing layer / buffer layer / polishing pad test sample before testing, and evenly apply thermal grease on both sides of the test sample. Set the pressure to 50N, the test temperature to 50°C, and the safety temperature to 340°C.

[0116] Tensile strength of polishing layer

[0117] National standard, use electronic vernier caliper and electronic universal testing machine for measurement.

[0118] Radial density uniformity of polishing layer

[0119] As shown in Figure 3, 15 square samples Y1 to Y15 are taken on the diameter of the polishing layer, and SG = m / v = m1 / (L^2*h) is calculated respectively, where m1 is the weight of the square sample Y1 to Y15, L is the side length of the square sample Y1 to Y15, and h is the thickness of the polishing layer; and SG0 is the point with the lowest density among the 15 samples.

[0120] Polishing layer groove volume

[0121] The difference between the volume V0 before grooving and the volume V after grooving and the ratio of the volume V0 of the polishing layer before grooving (V0-V) / V0 were calculated after simulating the polishing layer using SolidWorks 3D design software.

[0122] Shore hardness of polishing layer

[0123] Use REX digital display Shore D automatic measurement hardness tester or Bareiss digital display Shore D automatic measurement hardness tester for measurement. Cut the sample to be tested into 3"×3" square specimens. The thickness of the sample to be tested shall be not less than 5mm. The measuring point shall be at least 9mm from any edge of the sample. The hardness value on the same sample shall be measured at least 6mm apart and the maximum value shall be taken. The sample shall be tested under a standard environment of 23±2℃ and 50%±10% humidity.

[0124] Polishing performance evaluation of polishing pads

[0125] The polishing pads prepared in the examples and comparative examples were tested on a machine to evaluate their polishing performance. The test conditions were as follows:

[0126] The test machine is AMAT Refelxion (Modify 5Zone);

[0127] The polishing liquid was ANJI U3061A (slurry (g): DIW (g): 30% H2O2 (g) = 1:10:0.37), with a flow rate of 300 mL / min;

[0128] The conditioning disk is Saesol Disk AJ27, 6 lbf, in-situ 100%; Platen / Head Speed ​​= 97 / 91;

[0129] Zone Pressure: RR / Z1 / Z2 / Z3 / Z4 / Z5:5.90 / 5.10 / 2.40 / 2.15 / 2.10 / 2.20;

[0130] The wafers used are Semitech 754 Patterned wafers, Cu Blanket wafers with a Pre Thickness of 10-12KA.

[0131] The change of removal rate during polishing was recorded, and the data of 0 / 5hrs / 10hrs / 15hrs / 20hrs were recorded. The change of polishing rate non-uniformity (NU) was recorded and the average value was calculated using a four-probe film thickness meter (NAPSON Crestest / RG3000).

[0132] Defect evaluation

[0133] The defects on the polished substrate after polishing are obtained using KLA-Tencor Inspection was performed using the SP2 defect inspection system. The defect size detected was 0.16 μm. ○○ indicates almost no defects, ○ indicates very few defects, × indicates a few defects, ×× indicates a relatively large number of defects, and ××× indicates a large number of defects.

[0134] Example 1-1

[0135] This embodiment provides a polishing pad, and the preparation method thereof is as follows:

[0136] Step 1: Take 32.52 parts by mass of TDI, 8 parts by mass of HMDI, 53.78 parts by mass of PTMEG1000 and 5.7 parts by mass of DEG to react to obtain an isocyanate-terminated prepolymer, heat it to 25-65°C, and degas it under vacuum (-0.095 MPa) for 2 hours to remove the gas and small molecular compounds in the prepolymer; then add 8.99 parts by mass of a hollow microsphere polymer 551DE40d42 with an average particle size of 40 μm, stir it so that the hollow microsphere polymer is evenly dispersed in the prepolymer, degas it again under vacuum (-0.095 MPa) for 2 hours, and set aside.

[0137] Step 2: Heat 25.54 parts by mass of MOCA to 115° C. and set aside.

[0138] Step 3: The prepolymer and curing agent were mixed under high shear conditions and then cast into a circular mold to form a 12 cm thick casting block. The block was allowed to stand at room temperature for 10 minutes and then cured in a 100°C oven for 16 hours. After curing, the block was allowed to cool to room temperature in the oven and then cut into 80 mil thick sheets, totaling 60 sheets.

[0139] Step 4: The groove shape is concentric grooves with a blank (ungrooved) area in the center. The groove parameters are: groove depth 30mil, groove width 20mil, groove spacing 120mil, and the diameter of the center blank area is 2 inches. After grooving, it becomes the polishing layer.

[0140] Step 5: Use double-sided tape for the intermediate glue and back glue layer, use the intermediate glue to bond the above-mentioned polishing layer and the buffer layer, and bond the back glue layer on the other side of the buffer layer (the side not bonded with the polishing layer) to obtain the polishing pad P1-1, wherein the buffer layer uses a polyurethane-impregnated non-woven fabric material (SUBA).

[0141] Example 1-2

[0142] This embodiment provides a polishing pad P1-2, the preparation method of which is different from that of Example 1-1 in that: the isocyanate-terminated prepolymer is obtained by reacting 32.3 parts by mass of TDI and 7.84 parts by mass of HMDI, 54.21 parts by mass of PTMEG1000 and 5.65 parts by mass of DEG; the hollow microsphere polymer is 6.76 parts by mass of 551DE40d42 with an average particle size of 40 μm; 25.11 parts by mass of MOCA is selected as the curing agent; the rest is the same as Example 1-1.

[0143] Examples 1-3

[0144] This embodiment provides a polishing pad P1-3, the preparation method of which is different from that of Example 1-1 in that: the isocyanate-terminated prepolymer is obtained by reacting 39.01 parts by mass of TDI, 55.08 parts by mass of PTMEG1000 and 5.91 parts by mass of DEG; the hollow microsphere polymer is 6.08 parts by mass of 551DE40d42 with an average particle size of 40 μm; the curing agent is 26.35 parts by mass of MOCA, and the rest is the same as Example 1-1.

[0145] Examples 1-4

[0146] This embodiment provides a polishing pad P1-4, the preparation method of which is different from that of Example 1-1 in that: the isocyanate-terminated prepolymer is obtained by reacting 31.48 parts by mass of TDI and 7.63 parts by mass of HMDI, 55.88 parts by mass of PTMEG1000 and 5.01 parts by mass of DEG; the hollow microsphere polymer is 9.47 parts by mass of 461DE20d70 with an average particle size of 20 μm; the curing agent is 24.85 parts by mass of MOCA, and the rest is the same as Example 1-1.

[0147] Examples 1-5

[0148] This embodiment provides a polishing pad P1-5, the preparation method of which is different from that of Example 1-1 in that: the isocyanate-terminated prepolymer is obtained by reacting 38.84 parts by mass of TDI, 55.29 parts by mass of PTMEG1000 and 5.87 parts by mass of DEG; the hollow microsphere polymer is 7.57 parts by mass of 461DE20d70 with an average particle size of 20 μm; the curing agent is 26.16 parts by mass of MOCA, and the rest is the same as Example 1-1.

[0149] Examples 1-6

[0150] This embodiment provides a polishing pad P1-6, the preparation method of which is different from that of Example 1-1 in that: the isocyanate-terminated prepolymer is obtained by reacting 25.67 parts by mass of TDI and 5.42 parts by mass of HMDI, 65.30 parts by mass of PTMEG1400 and 3.61 parts by mass of DEG; the hollow microsphere polymer is 6.62 parts by mass of 461DE20d70 with an average particle size of 20 μm; the curing agent is selected to use 28.88 parts by mass of M-CDEA, and the rest is the same as Example 1-1.

[0151] Examples 1-7

[0152] This embodiment provides a polishing pad P1-7, the preparation method of which is different from that of Example 1-1 in that: the isocyanate-terminated prepolymer is obtained by reacting 31.97 parts by mass of TDI, 4.22 parts by mass of HMDI and 63.81 parts by mass of PTMEG650; the hollow microsphere polymer is 2.87 parts by mass of 551DE40d42 with an average particle size of 40 μm; and the curing agent is 23.63 parts by mass of MOCA. The rest is the same as Example 1-1.

[0153] Examples 1-8

[0154] This embodiment provides a polishing pad P1-8, the preparation method of which is different from that of Example 1-1 in that: the isocyanate-terminated prepolymer is obtained by reacting 34.31 parts by mass of MDI and 65.69 parts by mass of PPG (Bluestar Dongda polyether polyol product MN-3050D); the hollow microsphere polymer is 2.6 parts by mass of 551DE40d42 with an average particle size of 40 μm; the curing agent is selected to use 23.11 parts by mass of low molecular weight diol (Dai Nippon Ink PANDEX TM-228), and the rest is the same as Example 1-1.

[0155] Examples 1-9

[0156] This embodiment provides a polishing pad, and the preparation method thereof is as follows:

[0157] Step 1: Take 37.72 parts by mass of TDI, 56.84 parts by mass of PTMEG1000 and 5.44 parts by mass of DEG to react to obtain an isocyanate-terminated prepolymer, heat it to 25-65°C, and degas it under vacuum (-0.095 MPa) for 2 hours to remove the gas and small molecular compounds in the prepolymer; then add 5.59 parts by mass of hollow microsphere polymer 551DE40d42 with an average particle size of 40 μm, stir to make the hollow microsphere polymer uniformly dispersed in the prepolymer, degas it again under vacuum (-0.095 MPa) for 2 hours, and set aside.

[0158] Step 2: Heat 25.25 parts by mass of MOCA to 115° C. and set aside.

[0159] Step 3: The prepolymer and curing agent were mixed under high shear conditions and then cast into a circular mold to form a 12 cm thick casting block. The block was allowed to stand at room temperature for 10 minutes and then cured in a 100°C oven for 16 hours. After curing, the block was allowed to cool to room temperature in the oven and then cut into 80 mil thick sheets, totaling 60 sheets.

[0160] Step 4: The groove shape is concentric grooves with a blank (ungrooved) area in the center. The groove parameters are: groove depth 30mil, groove width 20mil, groove spacing 120mil, and the diameter of the center blank area is 2 inches. After grooving, it becomes the polishing layer.

[0161] Step 5: Use double-sided tape for the intermediate glue and back glue layer, use the intermediate glue to bond the above-mentioned polishing layer and the buffer layer, and bond the back glue layer on the other side of the buffer layer (the side not bonded with the polishing layer) to obtain the polishing pad P1-9, wherein the buffer layer uses a polyurethane-impregnated non-woven fabric material (SUBA).

[0162] Examples 1-10

[0163] This embodiment provides a polishing pad P1-10, the preparation method of which is different from that of Example 1-9 in that: the isocyanate-terminated prepolymer is obtained by reacting 39.83 parts by mass of TDI, 53.86 parts by mass of PTMEG1000 and 6.31 parts by mass of DEG; the hollow microsphere polymer is 4.68 parts by mass of 551DE40d42 with an average particle size of 40 μm; the curing agent is selected to use 26.85 parts by mass of MOCA, and the rest is the same as Example 1-9.

[0164] Examples 1-11

[0165] This embodiment provides a polishing pad P1-11, the preparation method of which is different from that of Example 1-9 in that: the isocyanate-terminated prepolymer is obtained by reacting 38.91 parts by mass of TDI and 1.84 parts by mass of HMDI, 52.84 parts by mass of PTMEG1000 and 6.41 parts by mass of DEG; the hollow microsphere polymer is 8.39 parts by mass of 551DE40d42 with an average particle size of 40 μm; the curing agent is 27.27 parts by mass of MOCA, and the rest is the same as Example 1-9.

[0166] Examples 1-12

[0167] This embodiment provides a polishing pad P1-12, the preparation method of which is different from that of Example 1-9 in that: the isocyanate-terminated prepolymer is obtained by reacting 32.40 parts by mass of TDI and 7.14 parts by mass of HMDI, 55.01 parts by mass of PTMEG1000 and 5.45 parts by mass of DEG; the hollow microsphere polymer is 6.94 parts by mass of 461DE20d70 with an average particle size of 20 μm; the curing agent is 24.88 parts by mass of MOCA, and the rest is the same as Example 1-9.

[0168] Examples 1-13

[0169] This embodiment provides a polishing pad, and the preparation method thereof is as follows:

[0170] Step 1: Take 38.84 parts by mass of TDI, 55.29 parts by mass of PTMEG1000 and 5.87 parts by mass of DEG to react to obtain an isocyanate-terminated prepolymer, heat it to 25-65°C, and degas it under vacuum (-0.095 MPa) for 2 hours to remove the gas and small molecular compounds in the prepolymer; then add 7.57 parts by mass of hollow microsphere polymer 551DE40d42 with an average particle size of 40 μm, stir to make the hollow microsphere polymer uniformly dispersed in the prepolymer, degas it again under vacuum (-0.095 MPa) for 2 hours, and set aside.

[0171] Step 2: Heat 26.16 parts by mass of MOCA to 115° C. and set aside.

[0172] Step 3: The prepolymer and curing agent were mixed under high shear conditions and then cast into a circular mold to form a 12 cm thick casting block. The block was allowed to stand at room temperature for 10 minutes and then cured in a 100°C oven for 16 hours. After curing, the block was allowed to cool to room temperature in the oven and then cut into 80 mil thick sheets, totaling 60 sheets.

[0173] Step 4: The groove selection uses concentric grooves with a blank (ungrooved) area in the center. The groove parameters are: groove depth 30.5 mil, groove width 20.5 mil, groove spacing 120 mil, and the center blank area diameter is 1 inch. The polishing layer is formed after grooving, and the difference between the volume V0 before grooving and the volume V after grooving and the ratio of the volume V0 of the polishing layer before grooving to V0 (V0-V) / V0 is 0.081.

[0174] Step 5: Use double-sided tape for the intermediate glue and back glue layer, use the intermediate glue to bond the above-mentioned polishing layer and the buffer layer, and bond the back glue layer on the other side of the buffer layer (the side not bonded with the polishing layer) to obtain the polishing pad P1-13, wherein the buffer layer uses a polyurethane-impregnated non-woven fabric material (SUBA).

[0175] Examples 1-14

[0176] This embodiment provides a polishing pad P1-14, whose prepolymer and curing agent are the same as those in Example 1-13, except that the groove shape is different. The groove parameters in this embodiment are: the groove shape is a combination of concentric grooves and radial grooves, and there is a blank (ungrooved) area in the center. The concentric circle parameters are: groove depth 30.5 mil, groove width 20.5 mil, groove spacing 120 mil, and center blank area diameter 1 inch; radial lines: 8, groove width 78.7 mil, groove depth 32.5 mil. After grooving, it becomes a polishing layer, wherein the difference between the volume V0 before grooving and the volume V after grooving and the ratio of the volume V0 of the polishing layer before grooving (V0-V) / V0 is 0.088.

[0177] Examples 1-15

[0178] This embodiment provides a polishing pad, and the preparation method thereof is as follows:

[0179] Step 1: Take 31.48 parts by mass of TDI, 7.63 parts by mass of HMDI, 55.88 parts by mass of PTMEG1000 and 5.01 parts by mass of DEG to react to obtain an isocyanate-terminated prepolymer, heat it to 25-65°C, and degas it under vacuum (-0.095 MPa) for 2 hours to remove the gas and small molecular compounds in the prepolymer; then add 9.47 parts by mass of hollow microsphere polymer 461DE20d70 with an average particle size of 20 μm, stir it so that the hollow microsphere polymer is evenly dispersed in the prepolymer, degas it again under vacuum (-0.095 MPa) for 2 hours, and set aside.

[0180] Step 2: Heat 24.85 parts by mass of MOCA to 115° C. and set aside.

[0181] Step 3: The prepolymer and curing agent were mixed under high shear conditions and then cast into a circular mold to form a 12 cm thick casting block. The block was allowed to stand at room temperature for 10 minutes and then cured in a 100°C oven for 16 hours. After curing, the block was allowed to cool to room temperature in the oven and then cut into 80 mil thick sheets, totaling 60 sheets.

[0182] Step 4: Use XY grid grooves for groove selection. The groove parameters are: groove depth 22.4 mil, groove width 80.4 mil, groove spacing 1572 mil. The polishing layer is formed after grooving. The difference between the volume V0 before grooving and the volume V after grooving and the ratio of the volume V0 of the polishing layer before grooving (V0-V) / V0 is 0.02.

[0183] Step 5: Use double-sided tape for the intermediate glue and back glue layer, use the intermediate glue to bond the above-mentioned polishing layer and the buffer layer, and bond the back glue layer on the other side of the buffer layer (the side not bonded with the polishing layer) to obtain the polishing pad P1-15, wherein the buffer layer uses a polyurethane-impregnated non-woven fabric material (SUBA).

[0184] Examples 1-16

[0185] This embodiment provides a polishing pad P1-16, whose prepolymer and curing agent are the same as those in Example 1-15. The groove is selected to use an arc groove as shown in Figure 7. The groove parameters in this embodiment are: groove depth 34.7 mil, groove width 31.2 mil, and the polishing layer is formed after grooving. Among them, the difference between the volume V0 before grooving and the volume V after grooving and the ratio of the volume V0 of the polishing layer before grooving (V0-V) / V0 is 0.19.

[0186] Examples 1-17

[0187] This embodiment provides a polishing pad P1-17, whose prepolymer and curing agent are the same as those in Example 1-15, except that the groove shape is different. The groove parameters in this embodiment are: the groove selection uses a dot matrix punching groove as shown in Figure 8, and the groove parameters are: pore diameter 67 mil, hole spacing 215 mil, and the polishing layer after grooving, wherein the difference between the volume V0 before grooving and the volume V after grooving and the ratio of the volume V0 of the polishing layer before grooving (V0-V) / V0 is 0.145.

[0188] Comparative Example 1-1

[0189] This embodiment provides a polishing pad PD1-1, the preparation method of which is different from that of Example 1-1 in that: the isocyanate-terminated prepolymer is obtained by reacting 33.53 parts by mass of TDI, 7.94 parts by mass of HMDI, 52.86 parts by mass of PTMEG1000, and 5.67 parts by mass of DEG; 27.11 parts by mass of MOCA is selected as the curing agent, and the rest is the same as Example 1-1.

[0190] Comparative Example 1-2

[0191] This embodiment provides a polishing pad PD1-2, the preparation method of which is different from that of Example 1-1 in that: the isocyanate-terminated prepolymer is obtained by reacting 32.86 parts by mass of TDI, 7.19 parts by mass of HMDI, 54.28 parts by mass of PTMEG1000, and 5.67 parts by mass of DEG; 25.22 parts by mass of MOCA is selected as the curing agent, and the rest is the same as Example 1-1.

[0192] Comparative Examples 1-3

[0193] This embodiment provides a polishing pad PD1-3, the preparation method of which is different from that of Example 1-9 in that: the isocyanate-terminated prepolymer is obtained by reacting 36.14 parts by mass of TDI, 59.17 parts by mass of PTMEG1000 and 4.69 parts by mass of DEG; the hollow microsphere polymer is 9.68 parts by mass of 551DE40d42 with an average particle size of 40 μm; the curing agent is selected to use 24.24 parts by mass of MOCA, and the rest is the same as Example 1-9.

[0194] Comparative Examples 1-4

[0195] This comparative example provides a polishing pad PD1-4, whose prepolymer and curing agent are the same as those in Examples 1-4, except that the groove shape is different. The groove parameters in this embodiment are: the arc groove is selected as shown in Figure 9, and the groove parameters are: groove depth 35.5 mil, groove width 32.6 mil, and the polishing layer is formed after grooving. Among them, the difference between the volume V0 before grooving and the volume V after grooving and the ratio of the volume V0 of the polishing layer before grooving (V0-V) / V0 is 0.203.

[0196] Comparative Examples 1-5

[0197] This comparative example provides a polishing pad PD1-5, whose prepolymer and curing agent are the same as those in Examples 1-4, except that the groove shape is different. The groove parameters in this embodiment are: the groove selection uses an XY grid groove as shown in Figure 10, and the groove parameters are: groove depth 23.5 mil, groove width 84.1 mil, groove spacing 2868 mil; after grooving, it becomes a polishing layer, wherein the difference between the volume V0 before grooving and the volume V after grooving and the ratio of the volume V0 of the polishing layer before grooving (V0-V) / V0 is 0.015.

[0198] Comparative Examples 1-6

[0199] This comparative example provides a polishing pad PD1-6, whose prepolymer and curing agent are the same as those in Examples 1-4, except that the groove shape is different. The groove parameters in this embodiment are: the groove selection uses an XY grid groove as shown in Figure 11, and the groove parameters are: groove depth 24 mil, groove width 85.5 mil, groove spacing 3014 mil, and the angle between horizontal and vertical grid lines is 30°; after grooving, it becomes a polishing layer, wherein the difference between the volume V0 before grooving and the volume V after grooving and the ratio of the volume V0 of the polishing layer before grooving (V0-V) / V0 is 0.013.

[0200] Comparative Examples 1-7

[0201] This embodiment provides a polishing pad PD1-7, the preparation method of which is different from that of Example 1-1 in that: the isocyanate-terminated prepolymer is obtained by reacting 39.21 parts by mass of TDI, 54.85 parts by mass of PTMEG1000 and 5.94 parts by mass of DEG; the hollow microsphere polymer is 0.93 parts by mass of 551DE40d42 with an average particle size of 40 μm; the curing agent is 26.60 parts by mass of MOCA, and the rest is the same as Example 1-1.

[0202] Among them, in Examples 1-1 to 1-13, the groove shapes are all concentric grooves, and the grooving parameters are the same. Therefore, the difference between the volume V0 before grooving and the volume V after grooving and the ratio of the volume V0 of the polishing layer before grooving (V0-V) / V0 in Examples 1-1 to 1-13 are both 0.081.

[0203] The ratio of the density SG1 of the polishing layer at any point along the diameter direction to the minimum density SG0 of the polishing layer along the diameter direction involved in Examples 1-1 to 1-17 and Comparative Examples 1-1 to 1-7 is shown in Table 1, where "-" represents the minimum point itself; the physical parameters of the polishing layer involved in Examples 1-1 to 1-17 and Comparative Examples 1-1 to 1-7 and the performance indicators of the corresponding polishing pads P1-1 to P1-17 and PD1-1 to PD1-7 are shown in Table 2.

[0204] Table 1

[0205] Table 2

[0206] The thermal conductivity, the ratio of the density SG1 of the polishing layer at any point along the diameter to the minimum density SG0 of the polishing layer along the diameter, the difference between the volume V0 of the polishing layer before grooving and the volume V after grooving, and the ratio of the volume V0 of the polishing layer before grooving of the polishing layer prepared in Examples 1-1 to 1-17 are all within the protection range. The polishing pads prepared thereby exhibit excellent comprehensive polishing performance, especially when the density is lower than 0.73 g / cm 3 , NU is lower and defects are further reduced; the thermal conductivity of the polishing layers involved in Comparative Examples 1-1, 1-2 and 1-7 is higher than the upper limit of thermal conductivity in this application. The radial density changes of Comparative Examples 1-1 and 1-2 are also lower than the lower limit. Although their grinding rates are comparable, NU and defects are significantly deteriorated. This application focuses more on the changes in NU and defects. Even if the grinding rates are comparable, such degradation is unacceptable. The thermal conductivity of Comparative Example 1-3 is lower than the lower limit of thermal conductivity in this application, and also obtains poor comprehensive polishing performance. For the polishing layers involved in Comparative Examples 1-4 to 1-6, their (V0-V) / V0 is greater than or less than 0.19 or 0.02, and also exhibits poor comprehensive polishing performance.

[0207] Preparation Example 2-1

[0208] Place 6 parts by mass of TDI and 17.5 parts by mass of MDI into a 1L three-necked flask. Raise the reaction temperature to 70°C over 30 minutes. Once the TDI and MDI are completely melted, start the agitator at 300 rpm. Dissolve 57 parts by mass of polyester polyol Kurapol P-2010 and 3.4 parts by mass of polyether polyol PPG3000 and add them dropwise to the TDI and MDI over 1.5 hours. After the dropwise addition was completed, 0.005 parts by mass of dibutyltin dilaurate was added, and the reaction was continued at 80°C for 2 hours. The reactants were then degassed at a vacuum of -0.096 MPa at 80°C for 60 minutes to obtain a prepolymer having a free -NCO content of 7.5%. 6.2 parts by mass of 1,4-butanediol and 47 parts by mass of DMF were added to the prepolymer, mixed uniformly, and reacted at 80°C for 200 minutes to obtain the desired polyurethane resin solution. The solvent was then removed to obtain polyurethane resin A1.

[0209] 1. Prepare 30 parts by mass of polyester non-woven fabric with a density of 0.15 g / cm 3, fiber fineness is 3d, fiber length is 50mm; immersed in a polyurethane resin solution, wherein the polyurethane resin solution selects 15 parts by mass of polyurethane resin A1 as the polyurethane resin and selects 85 parts by mass of DMF as the solvent.

[0210] 2. Immerse at 60°C for 300 minutes, then use water for wet coagulation. After coagulation, take out the above materials, wash off the excess solvent in water, and dry at 120°C for 30 minutes to obtain a non-woven fabric impregnated with polyurethane, which is the coated impregnated non-woven fabric.

[0211] The obtained non-woven fabric coated with the resin was polished to a 50 mil thin sheet and then cut into the same shape as the polyurethane polishing layer to obtain the buffer layer S2-1.

[0212] Preparation Example 2-2

[0213] The preparation method of the buffer layer S2-2 is similar to that of Example 2-1, wherein the polyurethane resin A1 is replaced by the polyurethane resin produced by Lubrizol ESTANE ETE55DT3TPU series; non-woven fabric is; 31.3 parts by mass of polyester non-woven fabric, with a density of 0.21g / cm 3 , fiber fineness is 3d, and fiber length is 50mm.

[0214] Preparation Example 2-3

[0215] The preparation method of the buffer layer S2-3 is similar to that of Example 2-1, wherein the polyurethane resin A1 is replaced by the polyurethane resin produced by Lubrizol The ESTANE ETE50DT3TPU series non-woven fabric is 30 parts by mass of polyester non-woven fabric with a density of 0.33g / cm 3 , fiber fineness is 3d, and fiber length is 50mm.

[0216] Preparation Example 2-4

[0217] The preparation method of the buffer layer S2-4 is similar to that of Example 2-1, wherein the polyurethane resin A1 is replaced by the polyurethane resin produced by Lubrizol The ESTANE ETE50DT4TPU series non-woven fabric is 30 parts by mass of polyester non-woven fabric with a density of 0.42g / cm 3 , fiber fineness is 3d, and fiber length is 50mm.

[0218] Preparation Example 2-5

[0219] 1. Mix 100 parts by mass of LF900A isocyanate-terminated prepolymer and 4.8 parts by mass of SH-192 surfactant at 70°C, heat 16.9 parts by mass of MOCA to 115°C, completely melt it into a clear and transparent liquid, and then add it to the mixture of isocyanate-terminated prepolymer and surfactant. Install a stirrer and set the speed to 2000 rpm, stir for 10 minutes, and then slowly remove the stirrer.

[0220] 2. Before thickening, the mixed solution was cast into a cylindrical mold to form a 12 cm thick casting block. The block was then allowed to gel at 70°C for 15 minutes. The casting was then heated to 80°C over 30 minutes and cured for 16 hours. After curing, the block was cooled to room temperature in an oven and then cut into 50 mil thick sheets, which became the buffer layer S2-5.

[0221] Example 2-1

[0222] This embodiment provides a polishing pad, and the preparation method thereof is as follows:

[0223] Step 1: Take 39.01 parts by mass of TDI, 55.08 parts by mass of PTMEG1000 and 5.91 parts by mass of DEG to react to obtain an isocyanate-terminated prepolymer, heat it to 25-65°C, and degas it under vacuum (-0.095 MPa) for 2 hours to remove the gas and small molecular compounds in the prepolymer; then add 6.08 parts by mass of hollow microsphere polymer 551DE40d42 with an average particle size of 40 μm, stir it so that the hollow microsphere polymer is evenly dispersed in the prepolymer, degas it again under vacuum (-0.095 MPa) for 2 hours, and set aside.

[0224] Step 2: Heat 26.35 parts by mass of MOCA to 115° C. and set aside.

[0225] Step 3: The prepolymer and curing agent were mixed under high shear conditions and then cast into a circular mold to form a 12 cm thick casting block. The block was allowed to stand at room temperature for 10 minutes and then cured in a 100°C oven for 16 hours. After curing, the block was allowed to cool to room temperature in the oven and then cut into 80 mil thick sheets, totaling 60 sheets.

[0226] Step 4: The groove selection uses concentric grooves with a blank (ungrooved) area in the center. The groove parameters are: groove depth 30mil, groove width 20mil, groove spacing 120mil, and the radius of the center blank area is 60-70mm. After grooving, it becomes a polishing layer.

[0227] Step 5: Use double-sided tape for the intermediate adhesive and back adhesive layer. Use the intermediate adhesive to bond the polishing layer and the buffer layer S2-1, and bond the back adhesive layer on the other side of the buffer layer (the side not bonded with the polishing layer) to obtain the polishing pad P2-1.

[0228] Example 2-2

[0229] This embodiment provides a polishing pad P2-2, and steps 1 to 4 in its preparation method are the same as those in embodiment 2-1, except that in step 5, the buffer layer S2-1 is replaced by S2-2.

[0230] Example 2-3

[0231] This embodiment provides a polishing pad P2-3, the preparation method of which is different from that of Example 2-1 in that: the isocyanate-terminated prepolymer is obtained by reacting 31.97 parts by mass of TDI, 4.22 parts by mass of HMDI and 63.81 parts by mass of PTMEG650; the hollow microsphere polymer is 2.87 parts by mass of 551DE40d42 with an average particle size of 40 μm; and the curing agent is 23.63 parts by mass of MOCA. The rest is the same as Example 2-1.

[0232] Examples 2-4

[0233] This embodiment provides a polishing pad P2-4, the preparation method of which is different from that of Example 2-1 in that: the isocyanate-terminated prepolymer is obtained by reacting 32.52 parts by mass of TDI, 8 parts by mass of HMDI, 53.78 parts by mass of PTMEG1000, and 5.7 parts by mass of DEG; the hollow microsphere polymer is 8.99 parts by mass of 551DE40d42 with an average particle size of 40 μm; 25.54 parts by mass of MOCA is selected as the curing agent, and the rest is the same as Example 2-1; and the buffer layer S2-1 is replaced by S2-2 in step five.

[0234] Examples 2-5

[0235] This embodiment provides a polishing pad P2-5, the preparation method of which is different from that of Example 2-1 in that: the isocyanate-terminated prepolymer is obtained by reacting 38.84 parts by mass of TDI, 55.29 parts by mass of PTMEG1000 and 5.87 parts by mass of DEG; the hollow microsphere polymer is 7.57 parts by mass of 461DE20d70 with an average particle size of 20 μm; 26.16 parts by mass of MOCA are selected as the curing agent, and the rest are the same as Example 2-1; and the buffer layer S2-1 is replaced by S2-3 in step five.

[0236] Examples 2-6

[0237] This embodiment provides a polishing pad P2-6, the preparation method of which is different from that of Example 2-1 in that: the isocyanate-terminated prepolymer is obtained by reacting 38.84 parts by mass of TDI, 55.29 parts by mass of PTMEG1000 and 5.87 parts by mass of DEG; the hollow microsphere polymer is 7.57 parts by mass of 461DE20d70 with an average particle size of 20 μm; 26.16 parts by mass of MOCA are selected as the curing agent, and the rest are the same as Example 2-1; and the buffer layer S2-1 is replaced by S2-5 in step five.

[0238] Comparative Example 2-1

[0239] This embodiment provides a polishing pad PD2-1, the preparation method of which is the same as that of comparative example 1-1, except that: the isocyanate-terminated prepolymer is obtained by reacting 33.53 parts by mass of TDI, 7.94 parts by mass of HMDI, 52.86 parts by mass of PTMEG1000 and 5.67 parts by mass of DEG; 27.11 parts by mass of MOCA is selected as the curing agent, and the rest is the same as that of Example 2-1.

[0240] Comparative Example 2-2

[0241] This embodiment provides a polishing pad PD2-2, the preparation method of which is the same as that of Example 1-1, except that: the isocyanate-terminated prepolymer is obtained by reacting 32.52 parts by mass of TDI and 8 parts by mass of HMDI, 53.78 parts by mass of PTMEG1000 and 5.70 parts by mass of DEG; the hollow microsphere polymer is 8.99 parts by mass of 551DE40d42 with an average particle size of 40 μm; the curing agent is selected to use 25.54 parts by mass of MOCA, and the rest is the same as Example 2-1.

[0242] The physical properties of the polishing layers involved in Examples 2-1 to 2-6 and Comparative Examples 2-1 to 2-2, the physical properties of the buffer layers in Preparation Examples 2-1 to 2-5, and the performance indicators of the corresponding polishing pads P2-1 to P2-6 and PD2-1 to PD2-2 are shown in Table 3.

[0243] The thermal conductivities of the polishing pads P2-1 to P2-6 and PD2-1 to PD2-2 corresponding to Examples 2-1 to 2-6 and Comparative Examples 2-1 to 2-2 are shown in Table 4.

[0244] Table 3

[0245] Table 4

[0246] The polishing pads involved in Examples 2-1 to 2-6 showed more excellent comprehensive polishing performance, in which the NU was further reduced. Although the NU value of Comparative Example 2-1 was also low, it showed more defects. Comparative Example 2-2 showed poor comprehensive polishing performance. The comprehensive polishing performance of Comparative Example 2-1 and Comparative Example 2-2 is unacceptable in this field.

[0247] It should be noted that, based on the explanations and elaborations of the above description, those skilled in the art may make changes and modifications to the above embodiments. Therefore, the present invention is not limited to the specific embodiments disclosed and described above, and equivalent modifications and variations of the present invention should also fall within the scope of protection of the claims of the present invention. Furthermore, although certain specific terms are used in this description, these terms are for convenience only and do not constitute any limitation to the invention.

Claims

1. A polishing pad, wherein: The invention comprises a polishing layer, wherein the polishing layer is a closed-cell elastomer formed by a polyurethane substrate having continuous pore separation, the thermal conductivity of the polishing layer is between 0.04W / (m·K) and 0.075W / (m·K), the ratio of the density SG1 of any point along the diameter direction of the polishing layer to the minimum density SG0 of the polishing layer along the diameter direction is between 1.002 and 1.096, the surface of the polishing layer is engraved with grooves, the groove shapes include: one or more combinations of concentric circle grooves, radial grooves, arc grooves, XY grid grooves, and dot matrix punching grooves, the difference between the volume V0 of the polishing layer before groove engraving and the volume V after groove engraving and the ratio (V0-V) / V0 of the volume V0 of the polishing layer before groove engraving are between 0.02 and 0.

19.

2. The polishing pad according to claim 1, wherein The thermal conductivity of the polishing layer is between 0.048 W / (m·K) and 0.065 W / (m·K).

3. The polishing pad according to claim 1, wherein The density of the polishing layer is between 0.4 g / cm 3 ~0.73g / cm 3 Preferably, the density of the polishing layer is between 0.4 g / cm 3 ~0.65g / cm 3 between. 4 . The polishing pad according to claim 1 , wherein the tensile strength of the polishing layer is between 2 MPa and 18 MPa, and preferably, the tensile strength of the polishing layer is between 7 MPa and 14.5 MPa.

5. The polishing pad according to claim 1, wherein The ratio of the density SG1 of any point of the polishing layer along the diameter direction to the minimum density SG0 of the polishing layer along the diameter direction is between 1.002 and 1.

075.

6. The polishing pad according to claim 1, wherein The difference between the volume V0 of the polishing layer before grooving and the volume V after grooving and the ratio (V0-V) / V0 of the volume V0 of the polishing layer before grooving are between 0.02 and 0.

145.

7. The polishing pad according to claim 1, wherein: The polyurethane substrate is obtained by reacting a multifunctional isocyanate, a polyol and a curing agent; The multifunctional isocyanate comprises one or more combinations 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, m-xylylene diisocyanate, ethylene diisocyanate, 2,2,4-trimethylhexamethylene diisocyanate, 1,6-hexamethylene diisocyanate, 1,4-cyclohexane diisocyanate, 4,4'-dicyclohexylmethane diisocyanate, isophorone diisocyanate, and norbornane diisocyanate; The polyol comprises one or more combinations of polytetramethylene ether glycol, polyethylene glycol, polypropylene glycol, ethylene glycol, butanediol, diethylene glycol, neopentyl glycol, 2-methyl-1,3-propanediol, hexanediol, 3-methyl-1,5-pentanediol, 1,4-cyclohexanedimethanol, homopolymers and / or copolymers of ethylene oxide and propylene oxide.

8. The polishing pad according to any one of claims 1 or 7, wherein: The multifunctional isocyanate comprises one or more combinations of toluene diisocyanate, diphenylmethane diisocyanate, and 4,4'-dicyclohexylmethane diisocyanate; the polyol comprises one or more combinations of polytetramethylene ether glycol, diethylene glycol, butanediol, homopolymers and / or copolymers of ethylene oxide and propylene oxide.

9. The polishing pad according to claim 1, wherein: A buffer layer is included, wherein the thermal conductivity of the buffer layer is between 0.06 W / (m·K) and 0.09 W / (m·K).

10. The polishing pad according to any one of claims 1 or 9, wherein: The ratio of the thermal conductivity of the polishing layer to that of the buffer layer is between 0.5 and 1.

2.

11. A polishing pad, wherein: The polishing pad comprises a polishing layer, a buffer layer, an adhesive layer and a back adhesive layer, and the thermal conductivity of the polishing pad is between 0.04 W / (m·K) and 0.09 W / (m·K).

12. The polishing pad according to claim 11, wherein The polishing layer is a closed-cell elastomer formed by a polyurethane substrate with continuous pore separation, the thermal conductivity of the polishing layer is between 0.04W / (m·K) and 0.075W / (m·K), the ratio of the density SG1 of any point along the diameter direction of the polishing layer to the minimum density SG0 of the polishing layer along the diameter direction is between 1.002 and 1.096, the surface of the polishing layer is engraved with grooves, and the groove shapes include: one or more combinations of concentric grooves, radial grooves, arc grooves, XY grid grooves, and dot matrix punching grooves, and the difference between the volume V0 of the polishing layer before grooving and the volume V after grooving and the ratio (V0-V) / V0 of the volume V0 of the polishing layer before grooving are between 0.02 and 0.

19.

13. A method for manufacturing a semiconductor device, wherein: The method comprises the step of grinding the surface of a semiconductor device wafer using a polishing pad, wherein the polishing pad is the polishing pad according to any one of claims 1 to 10.

14. A method for manufacturing a semiconductor device, wherein: The method comprises the step of grinding the surface of a semiconductor device wafer using a polishing pad, wherein the polishing pad is the polishing pad according to any one of claims 11 to 12.

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