Chemical mechanical polishing pad buffer layer, preparation method, polishing pad and application

Abstract

The invention provides a chemical mechanical polishing pad buffer layer, a preparation method, a polishing pad and application, the buffer layer comprises a polyurethane layer and a supporting layer, and the polyurethane layer is formed by curing a slurry composition containing polyurethane, an anionic auxiliary agent, a nonionic auxiliary agent and a solvent. The hardness of the buffer layer is 60-80 Shore A, the compression ratio is 4-8%, and the density is 0.6-0.8 g / cm < 3 >. The surface flatness of the polishing pad during polishing can be improved, the adhesiveness of the buffer layer and the polishing layer is improved, the tolerance of the polishing pad is further improved, and the bulging problem of the polishing pad is reduced.

Description

Technical Field

[0001] This invention relates to the field of chemical mechanical polishing (CMP) technology, specifically to a CMP pad buffer layer, its preparation method, the polishing pad, and its application. Background Technology

[0002] Chemical mechanical polishing (CMP) is a surface treatment technology that combines chemical reactions and mechanical abrasion. The chemical reaction process involves the reaction between chemical reactants in the polishing slurry and the material surface, converting insoluble substances into soluble substances or softening high-hardness materials to form substances that are easier to remove. Mechanical abrasion, on the other hand, involves the relative movement of the material surface against the polishing pad, utilizing the abrasive particles in the abrasive slurry to create mechanical friction against the material surface, removing the easily removable substances generated during the chemical reaction process, which are then dissolved and carried away by the flowing liquid.

[0003] Polishing pads, as the main participants in physical abrasion and the carriers of chemical reactions, are indispensable key consumables in chemical mechanical polishing. The main structure of a polishing pad generally consists of three parts: an upper polishing layer, a middle buffer layer, and a lower adhesive backing layer. Hard polishing pads are generally used as coarse polishing materials to achieve high removal rates; soft polishing pads are generally used as fine polishing materials to achieve low defect rates.

[0004] For hard polishing pads, the main key parameters affecting their polishing performance are hardness, density, thickness, compression ratio, surface roughness, and swelling ratio. Among these, hardness and density are the most critical and are the main considerations when designing the formulation. Maintaining high hardness is beneficial for improving the removal efficiency of hard polishing pads, but it may lead to uneven polishing and the introduction of new defects. Summary of the Invention

[0005] As a key material in polishing pads, the buffer layer material plays an important role in buffering pressure and reducing edge effects. By further experimenting and optimizing the buffer layer material, the inventors attempted to solve the problems existing in the prior art and improve the performance of the polishing pad, thus completing this invention.

[0006] To address the shortcomings of existing technologies, this invention provides a chemical mechanical polishing pad buffer layer that offers unique compression recovery properties to improve stress uniformity in the center and edges of the polishing material, reduce the defect rate, increase the contact area between the polishing material and the polishing pad, and improve the flatness of the polishing material surface.

[0007] To achieve these objectives and other advantages according to the invention, the present invention provides a chemical mechanical polishing pad buffer layer comprising a polyurethane layer and a support layer, the polyurethane layer being cured from a slurry composition comprising polyurethane, additives, and a solvent; the buffer layer having a hardness of 60-80 Shore A; a compression ratio of 4-8%; and a density of 0.6-0.8 g / cm³. 3 .

[0008] Based on parts by weight, the amounts of polyurethane, anionic additives and nonionic additives in the slurry composition are 75:2-10:2-10.

[0009] Preferably, the thickness of the polyurethane layer is 0.2-0.8 mm, more preferably 0.3-0.6 mm.

[0010] Preferably, the thickness of the support layer is 110-240 μm, more preferably 150-200 μm.

[0011] Preferably, the surface of the cushioning pad is perforated and consists of alternating near-spherical foam pores and sponge pores.

[0012] Preferably, the 100% modulus of the polyurethane is 70-150 MPa, more preferably 85-125 MPa, and even more preferably 90-120 MPa.

[0013] Preferably, the nonionic additive is a polyether-organosilicon type, wherein the ratio of polyether segments to organosilicon segments is 65-95%: 5-35%, and more preferably 75-85%: 15-25%.

[0014] The present invention also provides a method for preparing the above-described chemical mechanical polishing pad buffer layer, comprising the following steps: S1: Polyurethane resin, anionic additives and nonionic additives are dissolved in a solvent to prepare a slurry composition; S2: The slurry composition is evenly coated on the support layer with a certain thickness, and then immersed in the coagulation liquid to solidify and form a shape, followed by washing and drying. S3: The dried product is subjected to surface perforation treatment to obtain a buffer layer with surface perforation. The buffer pad is composed of a polyurethane layer and a support layer bonded together.

[0015] The present invention also provides a chemical mechanical polishing pad, which is formed by bonding a polishing layer, a buffer layer as described above or a buffer layer prepared by the preparation method described above, and a release layer.

[0016] The present invention also provides an application of a chemical mechanical polishing pad in chemical mechanical polishing.

[0017] Compared with the prior art, the chemical mechanical polishing pad buffer layer provided by the present invention has the following beneficial effects:

[0018] (1) The buffer layer of the present invention can provide better elastic recovery for the polishing pad, improve the stress uniformity in the middle and edge of the polishing material, increase the contact area between the polishing material and the polishing pad, and improve the flatness of the polishing material surface.

[0019] (2) The buffer layer of the present invention is composed of alternating near-spherical foam pores and sponge pores, which improves the adhesion to the polishing layer, thereby improving the durability of the polishing pad and reducing the risk of bulging of the polishing pad. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the chemical mechanical polishing pad buffer layer prepared according to an embodiment of the present invention.

[0021] Figure 2 This is a cross-sectional microscopic image of the buffer layer of the chemical mechanical polishing pad in Embodiment 1 of the present invention, where the squares represent approximately spherical pores and the circles represent sponge-like through-holes. Detailed Implementation

[0022] To better understand the technical solution of the present invention, the following embodiments will further illustrate the method provided by the present invention. However, the present invention is not limited to the listed embodiments, but should also include any other known modifications within the scope of the claims of the present invention.

[0023] <Chemical Mechanical Polishing Pad Buffer Layer>

[0024] In an embodiment of the present invention, the buffer layer comprises a polyurethane layer and a support layer, wherein the polyurethane layer is formed by curing a slurry composition comprising polyurethane, anionic additives, nonionic additives and solvents.

[0025] In this embodiment of the invention, the hardness of the buffer layer is 60-80 Shore A; the compression ratio of the buffer layer is 4-8%; and the density of the buffer layer is 0.6-0.8 g / cm³. 3 .

[0026] In this embodiment of the invention, the buffer layer is prepared by coating a slurry composition onto a support layer, then immersing it in a coagulation liquid for curing and shaping. After washing and drying, a buffer layer with a porous structure is obtained. Compared to traditional non-woven fabric buffer layers, the buffer layer in this embodiment consists of an upper polyurethane foam layer and a lower support layer, forming a soft-on-top, hard-on-bottom structure. This provides greater adjustability in polishing applications, and the resulting polishing pad can improve the flatness of the polishing material surface.

[0027] Polyurethane, as the matrix resin in the slurry composition, can cross-link and cure with each other, thereby causing the slurry composition to cure. The slurry composition with polyurethane as the matrix resin has good mechanical strength and wear resistance after curing. The polyurethane in the embodiments of this application includes at least one of polyester polyurethane, polyether polyurethane, and polycarbonate polyurethane.

[0028] The polyurethane in this embodiment can be obtained commercially or by making it in-house. Both methods serve the same purpose: to act as the base resin for the slurry composition to ensure that the slurry composition can solidify during use.

[0029] In an embodiment of the present invention, the polyurethane resin is synthesized using the following steps:

[0030] S1. Add polyol, solvent, chain extender, and isocyanate to a reaction vessel to form a reaction solution with a solid content of 30wt% to 60wt% and a hard segment content of 45% to 59%.

[0031] S2. The reaction temperature is 60-90℃. When the online viscosity reaches 20000-35000 mPa·s, add solvent to dilute the solid content to 20wt%-45wt%. Continue the reaction until the online viscosity reaches 10000-20000 mPa·s, then add methanol to terminate the reaction.

[0032] S3. Continuously sample and test the viscosity. When the viscosity is stable, add a stabilizer and stir for 0.5 hours to obtain polyurethane resin.

[0033] In the above embodiments, the isocyanate can be any isocyanate commonly used in the manufacture of polyurethane, without particular limitation. Examples include: ethylene diisocyanate, tetramethylene diisocyanate, pentamethylene diisocyanate, hexamethylene diisocyanate, 2,2,4-trimethylhexamethylene diisocyanate, 2,4,4-trimethylhexamethylene diisocyanate, dodecanethylene diisocyanate, isophorone diisocyanate, isopropylidene bis(4-cyclohexyl)isocyanate, cyclohexylmethane diisocyanate, methylcyclohexyl diisocyanate, 4,4'-dicyclohexylmethane diisocyanate, lysine diisocyanate, 2,6-diisocyanate methylhexanoate, bis(2-isocyanate ethyl) fumarate, bis(2-isocyanate ethyl) carbonate, 2-isocyanate ethyl-2 Aliphatic or alicyclic diisocyanates such as 6-diisocyanate hexanoate, cyclohexane diisocyanate, methylcyclohexane diisocyanate, and bis(2-isocyanoethyl)-4-cyclohexene; 2,4'-diphenylmethane diisocyanate, 4,4'-diphenylmethane diisocyanate, 2,4-toluene diisocyanate, 2,6-toluene diisocyanate, isophenyl diisocyanate, terephthalic diisocyanate, isophenylmethylene diisocyanate, terephthalic diisocyanate, 1,5-naphthalene diisocyanate, 4,4'-diisocyanate biphenyl, 3,3'-dimethyl-4,4'-diisocyanate biphenyl, 3,3'-dimethyl-4,4'-diisocyanate diphenylmethane, and chlorophenyl-2 Aromatic diisocyanates such as 4-diisocyanate and tetramethylphenyldimethyl diisocyanate. They can be used alone or in combination of two or more.

[0034] In the above embodiments, the polyol is selected from one or more of polyester polyols, polyether polyols, or polycarbonate polyols, including but not limited to polypropylene glycol (PPG), polytetrahydrofuran ether diol (PTMG), polyethylene adipate (AA / EG), polybutylene adipate diol (AA / BG), polyethylene adipate-1,4-butanediol diol (EG / BG / AA), and polycarbonate diol (PCDL).

[0035] In the above embodiments, examples of chain extenders include: ethylene glycol, diethylene glycol, 1,2-propanediol, 1,3-propanediol, 2,2-diethyl-1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 2,3-butanediol, 1,4-butanediol, 1,5-pentanediol, neopentanediol, 1,6-hexanediol, 3-methyl-1,5-pentanediol, 1,4-bis(β-hydroxyethoxy)benzene, 1,4-cyclohexanediol, cyclohexanediol (1,4-cyclohexanediol, etc.), bis(β-hydroxyethyl) terephthalate, 1 Diols such as 9-nonanediol, m-phenylenediol, terephthalic acid diethanolamine, diethylene glycol, and triethylene glycol; ethylenediamine, trimethylenediamine, tetramethylenediamine, hexamethylenediamine, heptamethylenediamine, octamethylenediamine, nonamethylenediamine, decamethylenediamine, undecamethylenediamine, dodecamethylenediamine, 2,2,4-trimethylhexamethylenediamine, 2,4,4-trimethylhexamethylenediamine, 3-methylpentamethylenediamine, 1,2-cyclohexanediamine, 1,3-cyclohexanediamine, 1,4-cyclohexanediamine, 1,2-diaminopropane, hydrazine, phenylenediamine, isophorone diamine, piperazine, o-phenylenediamine, m-phenylenediamine, p-phenylenediamine, toluenediamine, xylenediamine, adipate dihydrazide, isophthalic acid dihydrazide, 4,4'-diaminodiphenylmethane, 4 4,4'-Diaminodiphenyl ether, 4,4'-bis(4-aminophenoxy)biphenyl, 4,4'-bis(3-aminophenoxy)biphenyl, 1,4-bis(4-aminophenoxy)benzene, 1,3-bis(4-aminophenoxy)benzene, 1,3-bis(3-aminophenoxy)benzene, 3,4'-diaminodiphenyl ether, 4,4'-diaminodiphenyl sulfone, 3,4-diaminodiphenyl sulfone, 3,3'-diaminodiphenyl sulfone, 4,4'-methylenebis(2-chloroaniline), 3,3'-dimethyl4,4'-diaminobiphenyl, 4,4'-diaminodiphenyl sulfide, 2,6-diaminotoluene, 2,4-diaminochlorobenzene, 1,2-diaminoanthraquinone, 1,4-diaminoanthraquinone, 3,3'-diaminobenzophenone, 3 Diamines include 4-diaminobenzophenone, 4,4'-diaminobenzophenone, 4,4'-diaminobibenzyl, 2,2'-diamino-1,1'-binaphthyl, 1,3-bis(4-aminophenoxy)alkane, 1,4-bis(4-aminophenoxy)alkane, 1,5-bis(4-aminophenoxy)alkane, and 1,n-bis(4-aminophenoxy)alkane (n is 3-10), 1,2-bis[2-(4-aminophenoxy)ethoxy]ethane, 9,9-bis(4-aminophenyl)fluorene, and 4,4'-diaminobenzoylaniline. These compounds can be used alone or in combination of two or more.

[0036] Preferably, the polyurethane resin used in this invention has a 100% modulus of 70-150 MPa, including but not limited to 70 MPa, 75 MPa, 80 MPa, 85 MPa, 90 MPa, 95 MPa, 100 MPa, 105 MPa, 110 MPa, 115 MPa, 120 MPa, 125 MPa, 130 MPa, 135 MPa, 140 MPa, 145 MPa, and 150 MPa, and more preferably 85-125 MPa. Here, 100% modulus refers to the tensile strength at 100% elongation.

[0037] As an anionic additive, in the embodiments of this application, the anionic additive includes at least one of higher fatty acid ester salts (such as sodium higher fatty acids), sulfonated salts (such as sodium diisooctyl succinate sulfonate), sulfate ester salts (such as sodium lauryl sulfate), and phosphate ester salts (such as potassium hexadecyl phosphate), preferably sodium diisooctyl succinate sulfonate.

[0038] As the aforementioned nonionic additive, in the embodiments of this application, the nonionic additive generally includes at least one of polyol type, polyoxyethylene type, and polyether-modified organosilicon. Polyol type includes sorbitan monooleate, etc., and polyoxyethylene type includes fatty alcohol polyoxyethylene ether, etc. Polyether-modified organosilicon is formed by graft copolymerization of polyether and organosilicon, and can be obtained commercially or prepared in-house. In the embodiments of this application, the polyether-modified organosilicon is prepared in-house. When prepared in-house, the polyether includes, but is not limited to, at least one of polyethylene glycol and polypropylene glycol; the organosilicon is preferably polydimethylsiloxane (PDMS). The ratio between polyether segments and organosilicon segments is preferably 65-95%:5-35%, more preferably 75-85%:15-25%.

[0039] In the embodiments of this application, the components, by mass parts, the slurry composition contains polyurethane, anionic additives and nonionic additives in a mass ratio of 75:2-10:2-10, preferably 75:3-8:3-6.

[0040] In the embodiments of this application, the organic solvent plays a role in dissolving and uniformly dispersing the solute, ensuring the homogeneity of the slurry composition; moreover, a solid content in the range of 18% to 30% is beneficial for ensuring a suitable viscosity of the slurry composition and for the curing and film formation of the slurry composition. Specifically, the organic solvents in the embodiments of this application generally include at least one of N,N-dimethylformamide, N,N-dimethylacetamide, N-methylpyrrolidone, dimethyl sulfoxide, methyl ethyl ketone, cyclohexanone, tetrahydrofuran, and 1,4-dioxane; as an example, N,N-dimethylformamide is used as the organic solvent in this embodiment.

[0041] Anionic and nonionic additives in the slurry composition work synergistically during the crosslinking and curing of polyurethane, promoting the formation of channels and pore-like structures. Anionic additives primarily accelerate the setting speed and increase cell size; nonionic additives, besides contributing to the formation of sponge-like pores, also participate in surface setting. The higher the modulus of the polyurethane, the faster the surface setting speed. The combined effect of these three additives helps the polyurethane form two different types of interconnected pore structures during crosslinking and curing: approximately spherical cells and sponge-like pores. Larger spherical cells result in larger surface openings in the buffer layer. When bonded to the polishing layer, the intermediate adhesive can penetrate into the spherical cells, making the adhesion between the buffer layer and the polishing layer stronger.

[0042] In this embodiment of the application, the buffer layer is formed by bonding a polyurethane layer and a support layer. The thickness of the polyurethane layer is 0.2 mm to 0.8 mm, for example, including but not limited to 0.2 mm, 0.3 mm, 0.4 mm, 0.5 mm, 0.6 mm, 0.7 mm, and 0.8 mm, and more preferably 0.3 mm to 0.6 mm.

[0043] The material of the support layer is not particularly limited, and can be any of polyethylene terephthalate (PET), polypropylene (PP), or polyethylene (PE). The thickness of the support layer is 110-240 μm, including but not limited to 110 μm, 120 μm, 130 μm, 140 μm, 150 μm, 160 μm, 170 μm, 180 μm, 190 μm, 200 μm, 210 μm, 220 μm, 230 μm, and 240 μm, with 150-200 μm being more preferred. In this embodiment, the support layer is PET, specifically single-sided frosted PET.

[0044] <Preparation method of buffer layer for chemical mechanical polishing pad>

[0045] A method for preparing a buffer layer for a chemical mechanical polishing pad, the method comprising the following steps:

[0046] S1: Polyurethane resin, anionic additives and nonionic additives are dissolved in an organic solvent to prepare a slurry composition;

[0047] S2: The slurry composition is evenly coated on the support layer with a certain thickness, and then immersed in the coagulation liquid to solidify and form a shape, followed by washing and drying.

[0048] S3: The dried product is subjected to surface perforation treatment to obtain a buffer layer with surface perforation. The buffer pad is composed of a polyurethane layer and a support layer bonded together.

[0049] In step S1), polyurethane can be obtained commercially or prepared in-house; both methods serve the same purpose: to act as the matrix resin for the slurry composition, ensuring that the slurry composition can solidify during use. The polyurethane resin used in this invention has a 100% modulus of 70-150 MPa, including but not limited to 70 MPa, 75 MPa, 80 MPa, 85 MPa, 90 MPa, 95 MPa, 100 MPa, 105 MPa, 110 MPa, 115 MPa, 120 MPa, 125 MPa, 130 MPa, 135 MPa, 140 MPa, 145 MPa, and 150 MPa, preferably 85-125 MPa.

[0050] The anionic additive includes at least one of the following: higher fatty acid ester salts (such as sodium higher fatty acid salts), sulfonated salts (such as sodium diisooctyl succinate sulfonate), sulfate ester salts (such as sodium lauryl sulfate), and phosphate ester salts (such as potassium hexadecyl phosphate), with sodium diisooctyl succinate being preferred.

[0051] The nonionic additives generally include at least one of polyol-type, polyoxyethylene-type, and polyether-modified organosilicon. Polyol-type includes sorbitan monooleate, etc., and polyoxyethylene-type includes fatty alcohol polyoxyethylene ether, etc. Polyether-modified organosilicon is formed by graft copolymerization of polyether and organosilicon, and can be obtained commercially or prepared in-house. In in-house preparation, the polyether includes, but is not limited to, at least one of polyethylene glycol and polypropylene glycol; the organosilicon is preferably polydimethylsiloxane (PDMS). In the embodiments of this application, the polyether-modified organosilicon is obtained in-house.

[0052] As the organic solvent, N,N-dimethylformamide is used only as a solvent. Those skilled in the art will understand that, in addition to N,N-dimethylformamide, the solvent may also be at least one of N,N-dimethylacetamide, N-methylpyrrolidone, dimethyl sulfoxide, methyl ethyl ketone, cyclohexanone, tetrahydrofuran, and 1,4-dioxane; more preferably, N,N-dimethylformamide is used.

[0053] In step S2), the uniform coating can be achieved using existing technology, and this invention has no limitations. For example, a coating machine or a scraper can be used for coating. The key to this invention is controlling the coating thickness to be 0.60–1.5 mm, including but not limited to 0.60 mm, 0.65 mm, 0.70 mm, 0.75 mm, 0.80 mm, 0.85 mm, 0.90 mm, 0.95 mm, 1.00 mm, 1.05 mm, 1.10 mm, 1.15 mm, 1.20 mm, 1.25 mm, 1.30 mm, 1.35 mm, 1.40 mm, 1.45 mm, and 1.50 mm, preferably 0.60–1.20 mm.

[0054] The material of the support layer is not particularly limited, and can be any of polyethylene terephthalate (PET), polypropylene (PP), or polyethylene (PE). The thickness of the support layer is 110-240 μm, including but not limited to 110 μm, 120 μm, 130 μm, 140 μm, 150 μm, 160 μm, 170 μm, 180 μm, 190 μm, 200 μm, 210 μm, 220 μm, 230 μm, and 240 μm, with 150-200 μm being more preferred. In this embodiment, the support layer is PET, specifically single-sided frosted PET.

[0055] The coagulation bath is a mixture of N,N-dimethylformamide and water, wherein the mass percentage of N,N-dimethylformamide in the coagulation bath is 5% to 15%, for example, 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, but not limited thereto, preferably 6% to 12%. In the embodiments of this application, the coagulation solution is a 10% DMF aqueous solution, and the drying temperature is 100-120°C.

[0056] In step S3), the hole-opening process in this embodiment of the application is to obtain a buffer layer with surface holes by sanding with sandpaper, wherein the thickness of the polyurethane layer is 0.2-0.8mm and the thickness of the support layer is 110-240μm.

[0057] <Chemical Mechanical Polishing Pad>

[0058] In this embodiment, the polishing pad is formed by bonding a polishing layer, the aforementioned buffer layer or the buffer layer prepared by the aforementioned method, and a release layer.

[0059] The present invention will be further described in detail below with reference to embodiments, so that those skilled in the art can implement it based on the description.

[0060] It should be noted that, unless otherwise specified, the experimental methods described in the following implementation plan are all conventional methods, and the reagents and materials described are all commercially available unless otherwise specified.

[0061] <Testing Methods>

[0062] 100% modulus of polyurethane: A polyurethane slurry with 40% solid content was coated onto a PET release film using a small coating machine, dried in a 75℃ oven, and cut into specimens with a width of 25mm and a total length of 75mm. The 100% modulus of the specimens was tested using an electronic universal testing machine (Shimadzu, AGS-X-10kN).

[0063] Buffer layer thickness: The microstructure of the buffer layer cross section was observed using a scanning electron microscope, and the thickness of the polyurethane layer and the buffer layer were measured using a benchtop thickness gauge.

[0064] <Synthesis example 1>

[0065] Synthesis of polyurethane (100% modulus 70.0 MPa)

[0066] (1) Add 120 parts by mass of polyethylene adipate (AA / EG) to the reactor, add 266 parts by mass of N,N-dimethylformamide (DMF) initially, stir for 10 min, and determine the water content <110 ppm; add 22 parts by mass of chain extender butanediol (BG), stir for 10 min until completely dissolved, add 75 parts by mass of diphenylmethane diisocyanate (MDI), control the isocyanate index R = 0.99, the solid content of the solution is 45%, turn on the mold temperature controller to heat to 85℃ for reaction, and control the hard segment content to 44.70%;

[0067] (2) When the system temperature rises to 85℃, the external circulation system is turned on, and the viscosity change is monitored in real time by an online viscometer. When the online viscosity reaches 25000 mPa·s, DMF is added to the reactor to dilute the solid content to 40%. The reaction continues until the online viscosity is 15000 mPa·s, and then 0.22 parts by mass of end-capping agent methanol is added to terminate the reaction.

[0068] (3) After the reaction is terminated, keep stirring and take a sample every 20 minutes to measure the viscosity (15000±300mPa・s, stable after 2 consecutive tests). Add 0.68 parts by weight of antioxidant 1010, stir for 0.5 hours and discharge to obtain polyurethane resin. The 100% modulus of polyurethane resin is 70.0MPa according to the test.

[0069] <Synthesis example 2>

[0070] Synthesis of polyurethane (100% modulus 90.2 MPa)

[0071] (1) Add 135.1 parts by weight of polytetrahydrofuran ether glycol (PTMG) to the reactor, add 316 parts by weight of N,N-dimethylformamide (DMF) initially, stir for 10 min, and determine the water content <110 ppm; add 28.3 parts by weight of chain extender butanediol (BG), stir for 10 min until completely dissolved, add 96 parts by weight of diphenylmethane diisocyanate (MDI), control the isocyanate index R = 0.99, the solid content of the solution is 45%, turn on the mold temperature controller to heat to 85℃ for reaction, and control the hard segment content to 47.92%;

[0072] (2) When the system temperature rises to 85℃, the external circulation system is turned on, and the viscosity change is monitored in real time by an online viscometer. When the online viscosity reaches 25000 mPa·s, DMF is added to the reactor to dilute the solid content to 40%. The reaction continues until the online viscosity is 15000 mPa·s, and then 0.26 parts by mass of end-capping agent methanol is added to terminate the reaction.

[0073] (3) After the reaction is terminated, keep stirring and take a sample every 20 minutes to measure the viscosity (15000±300mPa・s, stable after 2 consecutive tests). Add 0.81 parts by weight of antioxidant 1010, stir for 0.5 hours and discharge to obtain polyurethane resin. The 100% modulus of polyurethane resin is 90.2MPa according to the test.

[0074] <Synthesis example 3>

[0075] Synthesis of polyurethane (100% modulus 99.8 MPa)

[0076] (1) Add 139 parts by mass of polytetrahydrofuran ether glycol (PTMG) to the reactor, add 345 parts by mass of N,N-dimethylformamide (DMF) initially, stir for 10 min, and determine the water content <110 ppm; add 33 parts by mass of chain extender butanediol (BG), stir for 10 min until completely dissolved, add 111 parts by mass of diphenylmethane diisocyanate (MDI), control the isocyanate index R = 0.99, the solid content of the solution is 45%, turn on the mold temperature controller to heat to 85℃ for reaction, and control the hard segment content to 50.88%;

[0077] (2) When the system temperature rises to 85℃, the external circulation system is turned on, and the viscosity change is monitored in real time by an online viscometer. When the online viscosity reaches 25000 mPa·s, DMF is added to the reactor to dilute the solid content to 40%. The reaction continues until the online viscosity is 15000 mPa·s, and then 0.28 parts by mass of end-capping agent methanol is added to terminate the reaction.

[0078] (3) After the reaction is terminated, keep stirring and take a sample every 20 min to measure the viscosity (15000±300 mPa・s, stable after 2 consecutive tests). Add 0.88 parts by weight of antioxidant 1010, stir for 0.5 h and discharge to obtain polyurethane resin. The 100% modulus of polyurethane resin is 99.8 MPa according to the test.

[0079] <Synthesis example 4>

[0080] Synthesis of polyurethane (100% modulus 110.3 MPa)

[0081] (1) Add 147 parts by mass of polytetrahydrofuran ether glycol (PTMG) to the reactor, add 369 parts by mass of N,N-dimethylformamide (DMF) initially, stir for 10 min, and determine the water content <110 ppm; add 35.4 parts by mass of chain extender butanediol (BG), stir for 10 min until completely dissolved, add 120 parts by mass of diphenylmethane diisocyanate (MDI), control the isocyanate index R = 0.99, the solid content of the solution is 45%, turn on the mold temperature controller to heat to 85℃ for reaction, and control the hard segment content to 51.39%;

[0082] (2) When the system temperature rises to 85℃, the external circulation system is turned on, and the viscosity change is monitored in real time by an online viscometer. When the online viscosity reaches 25000 mPa·s, DMF is added to the reactor to dilute the solid content to 40%. The reaction continues until the online viscosity is 15000 mPa·s, and then 0.30 parts by weight of the end-capping agent methanol is added to terminate the reaction.

[0083] (3) After the reaction is terminated, keep stirring and take a sample every 20 minutes to measure the viscosity (15000±300mPa・s, stable after 2 consecutive tests). Add 0.95 parts by weight of antioxidant 1010, stir for 0.5 hours and discharge to obtain polyurethane resin. The 100% modulus of polyurethane resin is 110.3MPa according to the test.

[0084] <Synthesis example 5>

[0085] Synthesis of polyurethane (100% modulus 120.0 MPa)

[0086] (1) Add 145 parts by mass of polyethylene adipate (AA / EG) to the reactor, add 380.1 parts by mass of N,N-dimethylformamide (DMF) initially, stir for 10 min, and determine the water content <110 ppm; add 38.2 parts by mass of chain extender butanediol (BG), stir for 10 min until completely dissolved, add 128 parts by mass of diphenylmethane diisocyanate (MDI), control the isocyanate index R = 0.99, the solid content of the solution is 45%, turn on the mold temperature controller to heat to 85℃ for reaction, and control the hard segment content to 53.41%;

[0087] (2) When the system temperature rises to 85℃, the external circulation system is turned on and the viscosity change is monitored in real time by an online viscometer. When the online viscosity reaches 25000 mPa·s, DMF is added to the reactor to dilute the solid content to 40%. The reaction continues until the online viscosity is 15000 mPa·s. Then, 0.31 parts by mass of the end-capping agent methanol is added to terminate the reaction.

[0088] (3) After the reaction is terminated, keep stirring and take a sample every 20 minutes to measure the viscosity (15000±300mPa・s, stable after 2 consecutive tests). Add 0.97 parts by weight of antioxidant 1010, stir for 0.5 hours and discharge to obtain polyurethane resin. The 100% modulus of polyurethane resin is 120.0MPa according to the test.

[0089] <Synthesis example 6>

[0090] Synthesis of polyurethane (100% modulus 130.5 MPa)

[0091] (1) Add 145 parts by mass of polytetrahydrofuran ether glycol (PTMG) to the reactor, add 395 parts by mass of N,N-dimethylformamide (DMF) initially, stir for 10 min, and determine the water content <110 ppm; add 42.1 parts by mass of chain extender butanediol (BG), stir for 10 min until completely dissolved, add 135 parts by mass of diphenylmethane diisocyanate (MDI), control the isocyanate index R = 0.99, the solid content of the solution is 45%, turn on the mold temperature controller to heat to 85℃ for reaction, and control the hard segment content to 54.98%;

[0092] (2) When the system temperature rises to 85℃, the external circulation system is turned on, and the viscosity change is monitored in real time by an online viscometer. When the online viscosity reaches 25000 mPa·s, DMF is added to the reactor to dilute the solid content to 40%. The reaction continues until the online viscosity is 15000 mPa·s, and then 0.32 parts by mass of the end-capping agent methanol is added to terminate the reaction.

[0093] (3) After the reaction is terminated, keep stirring and take a sample every 20 min to measure the viscosity (15000±300mPa・s, stable after 2 consecutive tests). Add 1.01 parts by weight of antioxidant 1010, stir for 0.5 h and discharge to obtain polyurethane resin. The 100% modulus of polyurethane resin is 130.5MPa according to the test.

[0094] <Synthesis Example 7>

[0095] Synthesis of polyurethane (100% modulus 150.2 MPa)

[0096] (1) Add 148 parts by mass of polytetrahydrofuran ether glycol (PTMG) to the reactor, add 419 parts by mass of N,N-dimethylformamide (DMF) initially, stir for 10 min, and determine the water content <110 ppm; add 47.0 parts by mass of chain extender butanediol (BG), stir for 10 min until completely dissolved, add 148 parts by mass of diphenylmethane diisocyanate (MDI), control the isocyanate index R = 0.99, the solid content of the solution is 45%, turn on the mold temperature controller to heat to 85℃ for reaction, and control the hard segment content to 56.85%;

[0097] (2) When the system temperature rises to 85℃, the external circulation system is turned on, and the viscosity change is monitored in real time by an online viscometer. When the online viscosity reaches 25000 mPa·s, DMF is added to the reactor to dilute the solid content to 40%. The reaction continues until the online viscosity is 15000 mPa·s, and then 0.34 parts by mass of end-capping agent methanol is added to terminate the reaction.

[0098] (3) After the reaction is terminated, keep stirring and take a sample every 20 min to measure the viscosity (15000±300mPa・s, stable after 2 consecutive tests). Add 1.07 parts by weight of antioxidant 1010, stir for 0.5 h and discharge to obtain polyurethane resin. The 100% modulus of polyurethane resin is 150.2MPa according to the test.

[0099] <Synthesis example 8>

[0100] Polyether-modified silicone (PPG 65% / PDMS 35%)

[0101] (1) Add 65.00 g of allyl-terminated PPG to a dry reaction flask equipped with a stirrer, thermometer, condenser and nitrogen inlet tube. Under nitrogen protection, stir and slowly heat to 90±5°C, and dehydrate under vacuum (pressure -0.09MPa) for 45 minutes to remove trace amounts of moisture from the raw material;

[0102] (2) Cool the system temperature to 80±5°C, add Karstedt catalyst (0.20 g), and begin slowly adding hydrogen-containing silicone oil PDMS (35.00 g) dropwise over 30-60 minutes. After the addition is complete, allow the reaction to proceed for 4 hours. During this period, FT-IR can be used to monitor whether the reaction is essentially complete.

[0103] (3) After the reaction was completed, the temperature was raised to 120℃ and vacuum distilled (0.098 MPa) for 2 h to remove byproducts and unreacted substances, yielding a clear and transparent polyether-modified organosilicon product (98.2 g, yield 98.2%). The product was characterized by FT-IR and ¹H-NMR, and the ratio of polyether segments to organosilicon segments in the final product was calculated to be 65:35.

[0104] <Synthesis Example 9>

[0105] Polyether-modified silicone (PPG 70.6% / PDMS 29.4%)

[0106] (1) Add 70.60 g of allyl-terminated PPG to a dry reaction flask equipped with a stirrer, thermometer, condenser and nitrogen inlet tube. Under nitrogen protection, stir and slowly heat to 90±5°C, and dehydrate under vacuum (pressure -0.09MPa) for 45 minutes to remove trace amounts of moisture from the raw material;

[0107] (2) Cool the system temperature to 80±5°C, add Karstedt catalyst (0.18 g), and begin slowly adding hydrogen-containing silicone oil PDMS (30.06 g) dropwise over 30-60 minutes. After the addition is complete, allow the reaction to proceed for 4 hours. During this period, FT-IR can be used to monitor whether the reaction is essentially complete.

[0108] (3) After the reaction was completed, the temperature was raised to 120℃ and vacuum distilled (0.098 MPa) for 2 h to remove byproducts and unreacted substances, yielding a clear and transparent polyether-modified organosilicon product (97.8 g, yield 97.8%). The product was characterized by FT-IR and ¹H-NMR, and the ratio of polyether segments to organosilicon segments in the final product was calculated to be 70.6:29.4.

[0109] <Synthesis example 10>

[0110] Polyether-modified silicone (PPG 75.3% / PDMS 24.7%)

[0111] (1) Add 75.30 g of allyl-terminated PPG to a dry reaction flask equipped with a stirrer, thermometer, condenser and nitrogen inlet tube. Under nitrogen protection, stir and slowly heat to 90±5°C, and dehydrate under vacuum (pressure -0.09MPa) for 45 minutes to remove trace amounts of moisture from the raw material;

[0112] (2) Cool the system temperature to 80±5°C, add Karstedt catalyst (0.12 g), and begin slowly adding hydrogen-containing silicone oil PDMS (25.08 g) dropwise over 30-60 minutes. After the addition is complete, allow the reaction to proceed for 4 hours. During this period, FT-IR can be used to monitor whether the reaction is essentially complete.

[0113] (3) After the reaction was completed, the temperature was raised to 100℃ and vacuum distilled (0.098 MPa) for 1.5 h to remove byproducts and unreacted substances, yielding a clear and transparent polyether-modified organosilicon product (98.9 g, yield 98.9%). The product was characterized by FT-IR and ¹H-NMR, and the ratio of polyether segments to organosilicon segments in the final product was calculated to be 75.3:24.7.

[0114] <Synthesis Example 11>

[0115] Polyether-modified silicone (PPG 80.1% / PDMS 19.9%)

[0116] (1) Add 80.10 g of allyl-terminated PPG to a dry reaction flask equipped with a stirrer, thermometer, condenser and nitrogen inlet tube. Under nitrogen protection, stir and slowly heat to 90±5°C, and dehydrate under vacuum (pressure -0.09MPa) for 45 minutes to remove trace amounts of moisture from the raw material;

[0117] (2) Cool the system temperature to 80±5°C, add Karstedt catalyst (0.10 g), and begin slowly adding hydrogen-containing silicone oil PDMS (20.10 g) dropwise over 30-60 minutes. After the addition is complete, allow the reaction to proceed for 4 hours. During this period, FT-IR can be used to monitor whether the reaction is essentially complete.

[0118] (3) After the reaction was completed, the temperature was raised to 100℃ and vacuum distilled (0.098 MPa) for 1.5 h to remove byproducts and unreacted substances, yielding a clear and transparent polyether-modified organosilicon product (98.7 g, yield 98.7%). The product was characterized by FT-IR and ¹H-NMR, and the ratio of polyether segments to organosilicon segments in the final product was calculated to be 80.1:19.9.

[0119] <Synthesis example 12>

[0120] Polyether-modified silicone (PPG 84.8% / PDMS 15.2%)

[0121] (1) Add 84.80 g of allyl-terminated PPG to a dry reaction flask equipped with a stirrer, thermometer, condenser and nitrogen inlet tube. Under nitrogen protection, stir and slowly heat to 90±5°C, and dehydrate under vacuum (pressure -0.09MPa) for 45 minutes to remove trace amounts of moisture from the raw material;

[0122] (2) Cool the system temperature to 70±5°C, add Karstedt catalyst (0.09 g), and begin slowly adding hydrogen-containing silicone oil PDMS (15.28 g) dropwise over 30-60 minutes. After the addition is complete, allow the reaction to proceed for 4 hours. During this period, FT-IR can be used to monitor whether the reaction is essentially complete.

[0123] (3) After the reaction was completed, the temperature was raised to 90℃ and vacuum distilled (0.098 MPa) for 1.5 h to remove byproducts and unreacted substances, yielding a clear and transparent polyether-modified organosilicon product (98.5 g, yield 98.5%). The product was characterized by FT-IR and ¹H-NMR, and the ratio of polyether segments to organosilicon segments in the final product was calculated to be 84.8:15.2.

[0124] <Synthesis Example 13>

[0125] Polyether-modified silicone (PPG 90.0% / PDMS 10.0%)

[0126] (1) Add 90.00 g of allyl-terminated PPG to a dry reaction flask equipped with a stirrer, thermometer, condenser and nitrogen inlet tube. Under nitrogen protection, stir and slowly heat to 90±5°C, and dehydrate under vacuum (pressure -0.09MPa) for 45 minutes to remove trace amounts of moisture from the raw material;

[0127] (2) Cool the system temperature to 70±5°C, add Karstedt catalyst (0.08 g), and begin slowly adding hydrogen-containing silicone oil PDMS (10.02 g) dropwise over 30-60 minutes. After the addition is complete, allow the reaction to proceed for 4 hours. During this period, FT-IR can be used to monitor whether the reaction is essentially complete.

[0128] (3) After the reaction was completed, the temperature was raised to 90℃ and vacuum distilled (0.098 MPa) for 1.5 h to remove byproducts and unreacted substances, yielding a clear and transparent polyether-modified organosilicon product (98.3 g, yield 98.3%). The product was characterized by FT-IR and ¹H-NMR, and the ratio of polyether segments to organosilicon segments in the final product was calculated to be 90.0:10.0.

[0129] <Synthesis Example 14>

[0130] Polyether-modified silicone (PPG 94.8% / PDMS 5.2%)

[0131] (1) Add 94.80 g of allyl-terminated PPG to a dry reaction flask equipped with a stirrer, thermometer, condenser and nitrogen inlet tube. Under nitrogen protection, stir and slowly heat to 90±5°C, and dehydrate under vacuum (pressure -0.09MPa) for 45 minutes to remove trace amounts of moisture from the raw material;

[0132] (2) Cool the system temperature to 70±5°C, add Karstedt catalyst (0.06 g), and begin slowly adding hydrogen-containing silicone oil PDMS (5.21 g) dropwise over 30-60 minutes. After the addition is complete, allow the reaction to proceed for 4 hours. During this period, FT-IR can be used to monitor whether the reaction is essentially complete.

[0133] (3) After the reaction was completed, the temperature was raised to 90℃ and vacuum distilled (0.098 MPa) for 1.5 h to remove byproducts and unreacted substances, yielding a clear and transparent polyether-modified organosilicon product (98.1 g, yield 98.1%). The product was characterized by FT-IR and ¹H-NMR, and the ratio of polyether segments to organosilicon segments in the final product was calculated to be 94.8:5.2.

[0134] <Example 1>

[0135] Preparation of the buffer layer: 75 parts by mass of polyurethane (100% modulus of 110.3 MPa) prepared in Synthesis Example 4, 3 parts by mass of sodium diisooctyl succinate sulfonate, and 4 parts by mass of polyether-modified organosilicon (PPG 70.6% / PDMS 29.4%) prepared in Synthesis Example 9 were dissolved in 25 parts by mass of organic solvent DMF to prepare a slurry composition; then the slurry composition was coated on a 140 μm PET film with a thickness of 0.60 mm, cured in a coagulation bath with a mass ratio of 10% DMF aqueous solution, washed with water, and dried in an oven at 100°C for 20 min; then the surface was opened by a sanding process to finally obtain a buffer layer with a polyurethane layer with a thickness of 0.2 mm on the top and a PET support layer on the bottom.

[0136] Polishing layer: The polishing layer prepared using Example 7 of patent CN202211340233.7.

[0137] Preparation of polishing pad: Combine the polishing layer with the above-mentioned buffer layer, then attach the backing adhesive, and finally attach the release layer to obtain a polyurethane polishing pad.

[0138] Examples 2-28 and Comparative Examples 1-2

[0139] The synthesis methods of the polishing pads in Examples 2-28 and Comparative Examples 1-2 are the same as those in Example 1. The difference lies in the selection of raw materials, proportions and preparation processes of the buffer layer. The specific formulas are shown in Table 1.

[0140] Table 1

[0141]

[0142] <Comparative Example 3>

[0143] Buffer layer: Common polyurethane-impregnated polyester nonwoven fabric (thickness: 50mil, compression ratio: 4.50%, density: 0.33g / cm3, hardness: 69.8 Shore A).

[0144] Polishing layer: The polishing layer prepared using Example 7 of patent CN202211340233.7.

[0145] Preparation of polishing pad: Combine the polishing layer with the above-mentioned buffer layer, then attach the backing adhesive, and finally attach the release layer to obtain a polyurethane polishing pad.

[0146] <Comparative Example 4>

[0147] Buffer layer: Common polyurethane foam type buffer layer (thickness: 50mil, compression ratio: 7%, density: 0.65g / cm3, hardness: 40 Shore A).

[0148] Polishing layer: The polishing layer prepared using Example 7 of patent CN202211340233.7.

[0149] Preparation of polishing pad: Combine the polishing layer with the above-mentioned buffer layer, then attach the backing adhesive, and finally attach the release layer to obtain a polyurethane polishing pad.

[0150] <Evaluation Methods>

[0151] Using the buffer layers of Examples 1-28 and Comparative Examples 1-4 as evaluation objects, the hardness, compression ratio, polishing rate, and polishing uniformity of the buffer layers, as well as the polishing pads, were measured.

[0152] Buffer layer hardness: The hardness is measured using a Bareiss digital Shore A automatic hardness tester. The sample to be tested is punched into a 3cm circular sample. The measurement point is at least 9mm away from any edge of the sample, and the hardness value is measured at least 6mm apart on the same sample. The maximum value is taken. The sample needs to be tested in a standard environment of 23±2℃ and 50%±10% humidity.

[0153] Buffer layer compression ratio: The compression ratio is calculated according to the following formula: Compression ratio = ((T1-T2) / T1)×100%; where T1 is the thickness of the buffer layer after 60s of no load and 30kPa pressure, and T2 is the thickness of the buffer layer after 60s of load and 180kPa pressure from state T1; according to the above measurement method, the compression ratio is measured at multiple points on both sides of the buffer layer, and the average value of the compression ratio is calculated.

[0154] Polishing pad grinding rate: The polishing wafer was a silicon wafer, and the polishing slurry was ZX5201 from Hubei Dingze New Material Technology Co., Ltd. An Ebara 300X polishing machine from Japan was used to polish the oxide layer on the silicon wafer to determine the polishing rate (RR) of each hard polishing pad. The polishing parameters were: head pressure 2.1 psi, polishing slurry flow rate 300 ml / min. The polishing data of the test wafers were recorded, and the RR of five consecutive wafers was calculated and averaged as the recorded data.

[0155] Grinding rate non-uniformity: First, 49 locations are selected on the surface of the object to be polished for measurement, and the thickness at the selected points before and after the polishing test is recorded. Grinding rate non-uniformity can be calculated by the maximum (Max) and minimum (Min) difference in thickness at the 49 locations before and after the test, and the average thickness. The calculation formula is: Grinding rate non-uniformity = 100 * (Max - Min) / average value.

[0156] The test results of the above embodiments and comparative examples are shown in Table 2.

[0157] Table 2

[0158]

[0159] As shown in Table 2, the polishing pads prepared in Examples 1 to 28 with a buffer layer hardness of 60-80 Shore A, a compression ratio of 4-8%, and a density of 0.6-0.8 g / cm3 still have a high grinding rate and low grinding inhomogeneity, thus improving the flatness of the polishing material surface.

[0160] Using the polishing pads of Examples 1-28 as evaluation objects, the adhesion between the buffer layer and the polishing layer prepared in Examples 1-28 was characterized by the durability of the polishing pads (the time of bulging).

[0161] Polishing pad durability: The polishing pad was broken in using a disk (Huida, DK4300) with an Ebara 300X polishing machine from Japan. The state of the polishing pad was observed and the time it took for the polishing pad to bulge was recorded. The longer the time, the stronger the adhesion between the buffer layer and the polishing layer. The test results are shown in Table 3.

[0162] Table 3

[0163]

[0164] As shown in Table 3, compared with Example 28, the buffer layer and polishing layer prepared by Examples 1-27 using polyether-modified silicone with a ratio of 65-95%:5-35% of polyether segments and silicone segments have stronger adhesion.

[0165] The above are merely embodiments of this application and are not intended to limit the scope of protection of this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the scope of protection of this application.

Claims

1. A chemical mechanical polishing pad buffer layer, characterized in that, The buffer layer comprises a polyurethane layer and a support layer. The polyurethane layer is formed by curing a slurry composition containing polyurethane, anionic additives, nonionic additives, and a solvent. The buffer layer has a hardness of 60-80 Shore A, a compression ratio of 4-8%, and a density of 0.6-0.8 g / cm³. 3 .

2. The chemical mechanical polishing pad buffer layer as described in claim 1, characterized in that, Based on parts by weight, the amounts of polyurethane, anionic additives and nonionic additives in the slurry composition are 75:2-10:2-10.

3. The chemical mechanical polishing pad buffer layer as described in claim 1, characterized in that, The thickness of the polyurethane layer is 0.2-0.8 mm, preferably 0.3-0.6 mm.

4. The chemical mechanical polishing pad buffer layer as described in claim 1, characterized in that, The thickness of the support layer is 110-240μm, preferably 150-200μm.

5. The chemical mechanical polishing pad buffer layer as described in claim 1, characterized in that, The surface of the buffer pad is perforated and consists of alternating near-spherical foam pores and sponge pores.

6. The chemical mechanical polishing pad buffer layer as described in claim 1, characterized in that, The 100% modulus of the polyurethane is 70-150 MPa, preferably 85-125 MPa, and more preferably 90-120 MPa.

7. The chemical mechanical polishing pad buffer layer as described in claim 1, characterized in that, The nonionic additive is of the polyether-organosilicon type, with the ratio of polyether segments to organosilicon segments being 65-95%: 5-35%, and more preferably 75-85%: 15-25%.

8. A method for preparing a chemical mechanical polishing pad buffer layer as described in any one of claims 1-7, characterized in that, Includes the following steps: S1: Polyurethane resin, anionic additives and nonionic additives are dissolved in a solvent to prepare a slurry composition; S2: The slurry composition is evenly coated on the support layer with a certain thickness, and then immersed in the coagulation liquid to solidify and form a shape, followed by washing and drying. S3: The dried product is subjected to surface perforation treatment to obtain a buffer layer with surface perforation, wherein the buffer layer is composed of a polyurethane layer and a support layer bonded together.

9. A chemical mechanical polishing pad, characterized in that, The polishing pad is formed by bonding a polishing layer, a buffer layer as described in any one of claims 1-7 or a buffer layer prepared by the preparation method described in claim 8, and a release layer.

10. The application of the chemical mechanical polishing pad according to claim 9 in chemical mechanical polishing.

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