A chlorovinyl resin modified polyurethane composite polishing pad and a preparation method thereof

Abstract

The present application relates to the technical field of chemical mechanical planarization processing, and discloses a chlorovinyl resin modified polyurethane composite polishing pad, which is prepared from the following components in parts by weight: color paste 1000-2000 parts, non-ionic surfactant 15-45 parts, anionic surfactant 15-45 parts, dilution solvent 500-1000 parts, back adhesive 300-330 parts, chlorovinyl resin modified polyurethane wet-process resin 3000-4000 parts, and impregnated layer 170-200 parts. The chlorovinyl resin modified polyurethane composite polishing pad uses chlorovinyl resin modified polyurethane as the wet-process resin, the main chain of which is a polyurethane structure with hard and soft segments alternating, and the side chain is a chlorovinyl resin structure of chloroethylene-vinyl acetate-vinyl alcohol copolymer. The segment structure of the chlorovinyl resin modified polyurethane wet-process resin is more diversified, which can effectively increase the upper limit of the number average molecular weight, greatly improve the wear resistance and mechanical properties, and the prepared polishing pad has the characteristics of good wear resistance, high porosity, high removal rate and long service life. The application also discloses a preparation method of the chlorovinyl resin modified polyurethane composite polishing pad.

Description

Technical Field

[0001] This invention belongs to the technical field of chemical mechanical planarization, specifically relating to a chloroacetic acid resin modified polyurethane composite polishing pad and its preparation method. Background Technology

[0002] Chemical mechanical polishing (CMP) is a key process for achieving global uniform planarization of wafers in integrated circuit manufacturing. CMP uses a relatively soft material to polish the wafer to achieve a high-quality surface finish, and it is currently the only technology that can achieve both global and local planarization of the surface.

[0003] Polishing pads used in CMP processes are broadly classified into hard coarse polishing pads and soft fine polishing pads. In recent years, with the increasingly urgent market demand for high-precision advanced process devices, the consumption of fine polishing pads in CMP processes has also been increasing. Because domestically produced fine polishing pads generally suffer from insufficient wear resistance, poor mechanical properties, uneven pore size, low porosity, weak liquid carrying capacity, and short service life, they lead to problems such as low material removal rate, insufficient wafer flatness, and high surface defect rate in CMP processes. Therefore, most domestic wafer manufacturers primarily use imported fine polishing pads.

[0004] The prior art discloses a polishing pad, which is a linear structure polyurethane wet-process resin synthesized with diisocyanate and small molecule diol / amine as hard segments and polyester diol and polyether diol as soft segments. Its number-average molecular weight limit is low, the chain segment structure is simple and there are no hydrophilic groups. It generally has defects such as insufficient wear resistance and poor mechanical properties. The polishing pads prepared by it generally have shortcomings such as uneven pores, low porosity, weak liquid carrying capacity, low polishing removal rate and short service life. The prior art also discloses another type of polishing pad, which is a fine polishing pad prepared with polyethylene terephthalate (PET) film as a buffer layer. It requires coating slurry to be applied to a release film for solidification, washing, drying and shaping, and then peeling the coating layer off the release film. Finally, hot melt adhesive is used to bond the coating layer and the PET film together. This preparation process is relatively cumbersome, and the polishing pad prepared has a low compression ratio and resilience, and poor buffering effect. In the CMP fine polishing process, it is very easy to cause poor wafer flatness and high surface defect rate. Summary of the Invention

[0005] To address the shortcomings of the prior art, this invention provides a chloroacetic acid resin-modified polyurethane composite polishing pad. This pad utilizes a chloroacetic acid resin-modified polyurethane wet-process resin, with a main chain consisting of alternating hard and soft polyurethane segments, and side chains formed by copolymerization of vinyl chloride, vinyl acetate, and vinyl alcohol. The more diversified chain structure of the chloroacetic acid resin-modified polyurethane wet-process resin effectively increases the upper limit of the number-average molecular weight, significantly improving its wear resistance and mechanical properties. The resulting polishing pad exhibits excellent wear resistance, high porosity, high removal rate, and long service life. This invention also provides a method for preparing this chloroacetic acid resin-modified polyurethane composite polishing pad.

[0006] The technical effects to be achieved by this invention are realized through the following technical aspects:

[0007] In a first aspect, the present invention provides a chloroacetic acid resin modified polyurethane composite polishing pad, which is prepared from the following components in parts by weight:

[0008] Color paste 1000-2000 parts, nonionic surfactant 15-45 parts, anionic surfactant 15-45 parts, diluent 500-1000 parts, adhesive 300-330 parts, chlorinated vinyl acetate modified polyurethane wet process resin 3000-4000 parts, impregnation layer 170-200 parts.

[0009] In some embodiments, the chloroacetic acid resin modified polyurethane wet-process resin is prepared by weight of the following components: 40-60 parts of diisocyanate, 180-540 parts of polyether diol, 5-15 parts of aromatic diamine, 100-200 parts of chloroacetic acid resin, 1-5 parts of chain terminator, and 605-2460 parts of solvent.

[0010] The chloroacetic acid resin is a copolymer of vinyl chloride-vinyl acetate-vinyl alcohol, with a hydroxyl value between 50 and 100 mg KOH / g and a molecular weight between 30,000 and 50,000.

[0011] In some embodiments, the diisocyanate includes at least one of toluene-2,4-diisocyanate, toluene-2,6-diisocyanate, 4,4'-diphenylmethane diisocyanate, or 2,4'-diphenylmethane diisocyanate.

[0012] In some embodiments, the polyether diol is at least one of polytetrahydrofuran diol or polypropylene glycol; wherein the polytetrahydrofuran diol is PTMG-1000, PTMG-2000 or PTMG-3000, and the polypropylene glycol is PPG-1000, PPG-2000 or PPG-3000.

[0013] In some embodiments, the aromatic diamine includes at least one of 4,4'-diaminodiphenylmethane, 2,4'-diaminodiphenylmethane, 2,4-diaminotoluene, or 2,6-diaminotoluene;

[0014] The chain terminator is methanol, ethanol, or isopropanol.

[0015] In some embodiments, the chlorinated vinyl acetate-modified polyurethane wet-process resin is prepared by the following method:

[0016] Prepolymerization reaction: Polyether diol is dehydrated for 1 hour at 105-110℃ and negative pressure of 0.08-0.10 MPa, and diisocyanate is added and prepolymerized at 80-90℃ for 2-3 hours to obtain isocyanate-terminated prepolymer.

[0017] Chain extension reaction: a solvent and an aromatic diamine are added sequentially to the obtained prepolymer to extend the chain, and the reaction is maintained at 80-90℃ for 2-3 hours until the system solution polymerizes to a molecular weight between 60,000 and 80,000.

[0018] Grafting reaction: Add chloroacetic acid resin and maintain the grafting reaction at 80-90℃ for 3-4 hours to chemically graft the chloroacetic acid resin onto the polyurethane chain segment.

[0019] The reaction was terminated when the grafting reaction reached a number average molecular weight Mn between 120,000 and 150,000. A chain terminator was then added to terminate the reaction, and the product was discharged to obtain a chlorinated vinyl acetate-modified polyurethane wet-process resin.

[0020] In some embodiments, the color paste is carbon black paste or titanium dioxide paste;

[0021] The nonionic surfactant is sorbitan monostearate or sorbitan monooleate.

[0022] The anionic surfactant is sodium docusate or sodium dodecylbenzene sulfonate.

[0023] The solvent is N,N-dimethylformamide, N-methylpyrrolidone, or dimethyl sulfoxide;

[0024] The adhesive backing is a pressure-sensitive acrylic adhesive, with models 568HM2, 560PSD, or 5628C, and a thickness between 100 and 200 μm.

[0025] In some embodiments, the impregnated layer is prepared by weight of the following components: 2000-3000 parts of chloroacetic acid modified polyurethane wet-process resin, 4000-5000 parts of solvent, and 130-140 parts of non-woven fabric.

[0026] In some embodiments, in the impregnation layer, the viscosity of the impregnation slurry at 25°C is 200–500 mPa·s, and the resin impregnation ratio is 30%–35%.

[0027] The nonwoven fabric includes PET needle-punched nonwoven fabric or PET spunlace nonwoven fabric, and the thickness of the nonwoven fabric is between 0.8 and 1.0 mm, and the basis weight is between 130 and 140 g / m². 2 between.

[0028] In some embodiments, the impregnated layer is prepared by the following method:

[0029] Add chloroacetic acid resin-modified polyurethane wet-process resin and solvent, and disperse at a speed of 800-1000 r / min for 1-2 h until uniformly mixed; then degas under vacuum conditions of negative pressure 0.08-0.10 MPa for 2-3 h to obtain impregnation slurry; finally, mix nonwoven fabric and impregnation slurry evenly, place in DMF aqueous solution to solidify, wash with water, dry and shape to obtain impregnation layer.

[0030] In a second aspect, the present invention employs a method for preparing a chlorinated vinyl acetate resin-modified polyurethane composite polishing pad, comprising the following steps:

[0031] Step 1: Dispersing the coating slurry. Add the chlorinated vinyl acetate modified polyurethane wet-process resin, color paste, nonionic surfactant, anionic surfactant and diluent to a container and disperse at a speed of 800-1000 r / min for 2-3 hours until the mixture is uniform to obtain the coating slurry.

[0032] Step 2: Degassing the coating slurry. Degas the evenly dispersed coating slurry under a negative pressure of 0.08-0.10 MPa for 3-4 hours. The viscosity of the coating slurry at 25°C is 10000-15000 mPa·s.

[0033] Step 3: Wet coating and coagulation. A layer of coating slurry obtained in Step 2 is coated on the impregnated layer. The wet film thickness of the coating slurry is 1.5-2.0 mm. The film is then placed in a DMF aqueous solution with a temperature of 25-45℃ and a mass concentration of 10%-30% for coagulation and foaming to obtain a coagulated sample.

[0034] Step 4: Washing and drying. Place the solidified sample in deionized water at 40-60℃ to wash off the solvent. Repeat this process more than 10 times until the solvent concentration is less than 1%. Then, dry the sample at 100-120℃ for 4-6 hours to set the sample.

[0035] Step 5: Grinding and hot pressing. Grind the shaped sample with 150-400 grit sandpaper to remove the dense layer on the surface of the coating layer and expose the upright cells. Then, hot press the pattern at a temperature of 120-140℃.

[0036] Step Six: Adhesive backing and cutting. The hot-pressed sample is adhesive backed and cut into round pieces to obtain the chlorinated vinyl resin modified polyurethane composite polishing pad.

[0037] In summary, the present invention has at least the following advantages:

[0038] 1. The chloroacetic acid resin modified polyurethane composite polishing pad provided by the present invention is prepared using chloroacetic acid resin modified polyurethane wet-process resin as the main raw material. The wet-process resin is a chloroacetic acid resin grafted and modified polyurethane, whose main chain is a polyurethane structure with alternating hard and soft segments, and whose side chain is a chloroacetic acid resin structure copolymerized with vinyl chloride, vinyl acetate and vinyl alcohol. This makes the overall chain structure more diversified, which can effectively increase the upper limit of the number average molecular weight, and greatly improve its wear resistance and mechanical properties. The polishing pad prepared has good wear resistance, high removal rate and long service life, which effectively solves the problems of insufficient wear resistance, poor mechanical properties and short service life of existing fine polishing pads.

[0039] 2. The chlorinated vinyl acetate resin-modified polyurethane composite polishing pad provided by the present invention uses chlorinated vinyl acetate resin-modified polyurethane as the wet process resin. In this process, chlorinated vinyl acetate resin graft modification of polyurethane involves introducing unreacted hydroxyl groups onto the side chains of the wet process resin. In the wet foaming process, this helps to promote solvent and water exchange, forming more uniform water droplet-shaped cells and increasing its porosity. This effectively solves the problems of uneven cell size, low porosity, insufficient liquid carrying capacity, poor affinity with polishing liquid, and low polishing removal rate that are common in existing fine polishing pads.

[0040] 3. The preparation method of the chloroacetic acid resin modified polyurethane composite polishing pad provided by the present invention uses an impregnation process to prepare an impregnation layer by synthesizing chloroacetic acid resin modified polyurethane wet-process resin and non-woven fabric, which replaces PET film as the buffer layer of the polishing pad. Then, the coating slurry is directly scraped onto the impregnation layer, and then solidified, washed, and dried. The impregnation layer and the coating layer do not need to be peeled off or bonded with hot melt adhesive, which greatly simplifies the cumbersome preparation process of using PET film as a buffer layer. It can also effectively improve the compression ratio and resilience of the polishing pad, and solve the problems of poor wafer flatness and high surface defect rate in CMP fine polishing process. Attached Figure Description

[0041] Figure 1 This is a simplified flowchart of the preparation method of the chloroacetic acid resin modified polyurethane composite polishing pad of the present invention.

[0042] Figure 2This is a surface SEM image of the chloroacetic acid resin modified polyurethane composite polishing pad prepared in Example 1 of the present invention.

[0043] Figure 3 This is a cross-sectional SEM image of the chloroacetic acid resin modified polyurethane composite polishing pad prepared in Example 1 of the present invention. Detailed Implementation

[0044] To facilitate understanding of the present invention, a more comprehensive description will be given below in conjunction with the accompanying drawings and specific embodiments. Preferred embodiments of the invention are shown in the embodiments. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a thorough and complete understanding of the disclosure of the present invention.

[0045] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention.

[0046] The use of terms such as "one embodiment," "implementation," and "exemplary embodiment" in the specification means a described implementation, but not every implementation may include specific features, structures, or characteristics. Specific features, structures, or characteristics are included. Furthermore, such phrases do not necessarily refer to the same implementation. Additionally, when a specific feature, structure, or characteristic is described in connection with certain implementations, whether explicitly described or not, the effect of applying that feature, structure, or characteristic to other implementations is within the knowledge of those skilled in the art.

[0047] Values ​​expressed as ranges should be interpreted flexibly, including not only the values ​​explicitly listed as the limits of the range, but also all individual values ​​or subranges included within the range, as if each value and subrange were clearly stated. For example, a concentration range of “about 0.1% to about 5%” should be interpreted as including not only the explicitly listed values ​​of about 0.1% to about 5% by weight, but also the individual (mass) concentrations (e.g., 1%, 2%, 3%, and 4%) and subranges (e.g., 0.1% to 0.5%, 1.1% to 2.2%, and 3.3% to 4.4%) within the specified range.

[0048] As described herein, unless otherwise stated, the term "a" is used to include one or more, and the term "or" is used to refer to a non-exclusive "or". Furthermore, when terms or terms used herein are not otherwise defined, they should be understood as being for descriptive purposes only and not for limiting purposes. Additionally, all publications, patents, and patent documents mentioned in the specification are incorporated herein by reference in their entirety as if individually incorporated by reference. If there is any inconsistency between the usage in this document and those documents incorporated by reference, the usage in the cited references shall be considered supplementary to this document. In the event of irreconcilable inconsistencies, the usage herein shall prevail.

[0049] A chloroacetic acid resin modified polyurethane composite polishing pad is prepared by weight of the following components: 1000-2000 parts of color paste, 15-45 parts of nonionic surfactant, 15-45 parts of anionic surfactant, 500-1000 parts of diluent, 300-330 parts of adhesive, 3000-4000 parts of chloroacetic acid resin modified polyurethane wet-process resin, and 170-200 parts of impregnation layer.

[0050] Among the above components, the color paste is selected from carbon black paste or titanium dioxide paste;

[0051] The nonionic surfactant is selected from sorbitan monostearate (Span-60) or sorbitan monooleate (Span-80);

[0052] The anionic surfactant is selected from sodium docusate (OT-100) or sodium dodecylbenzenesulfonate (SDBS);

[0053] The diluent is N,N-dimethylformamide (DMF), N-methylpyrrolidone (NMP), or dimethyl sulfoxide (DMSO).

[0054] The adhesive backing is a pressure-sensitive acrylic adhesive, preferably 568HM2, 560PSD or 5628C from Sekisui Chemicals Co., Ltd., Japan, with a thickness between 100 and 200 μm.

[0055] The chlorinated vinyl acetate-modified polyurethane wet-process resin is prepared by weight of the following components: 40-60 parts diisocyanate, 180-540 parts polyether diol, 5-15 parts aromatic diamine, 100-200 parts chlorinated vinyl acetate resin, 1-5 parts chain terminator, and 605-2460 parts solvent; the solid content of the chlorinated vinyl acetate-modified polyurethane wet-process resin is 25.0wt%-35.0wt%, the viscosity at 25℃ is 150000-200000 mPa·s, and the number average molecular weight Mn is 120000-150000.

[0056] Among them, the chloroacetic acid resin is a copolymer of vinyl chloride-vinyl acetate-vinyl alcohol, with a hydroxyl value between 50 and 100 mg KOH / g and a molecular weight between 30,000 and 50,000.

[0057] The diisocyanate is selected from at least one of toluene-2,4-diisocyanate (2,4-TDI), toluene-2,6-diisocyanate (2,6-TDI), 4,4'-diphenylmethane diisocyanate (4,4-MDI) or 2,4'-diphenylmethane diisocyanate (2,4-MDI).

[0058] The polyether diol is selected from at least one of polytetrahydrofuran glycol or polypropylene glycol; wherein the polytetrahydrofuran glycol is specified as PTMG-1000, PTMG-2000 or PTMG-3000, and the polypropylene glycol is specified as PPG-1000, PPG-2000 or PPG-3000.

[0059] The aromatic diamine is selected from at least one of 4,4'-diaminodiphenylmethane (4,4-MDA), 2,4'-diaminodiphenylmethane (2,4-MDA), 2,4-diaminotoluene (2,4-TDA) or 2,6-diaminotoluene (2,6-TDA);

[0060] The chain terminator is selected from methanol, ethanol or isopropanol.

[0061] The above-mentioned chlorinated vinyl acetate-modified polyurethane wet-process resin is prepared by the following method:

[0062] (1) Prepolymerization reaction: Polyether diol is dehydrated for 1 hour at 105-110℃ and negative pressure of 0.08-0.10 MPa, and diisocyanate is added and prepolymerized at 80-90℃ for 2-3 hours to obtain isocyanate-terminated prepolymer.

[0063] (2) Chain extension reaction: Add solvent and aromatic diamine to the obtained prepolymer in sequence to extend the chain, and keep the reaction at 80-90℃ for 2-3 hours until the system solution polymerizes to a molecular weight between 60,000 and 80,000.

[0064] (3) Grafting reaction: Add chlorinated resin and maintain 80-90℃ for 3-4 hours to chemically graft the chlorinated resin onto the polyurethane chain segment.

[0065] (4) Terminate the reaction. When the grafting reaction reaches a number average molecular weight Mn between 120,000 and 150,000, add a chain terminator to terminate the reaction, discharge the material, and obtain the chlorinated vinyl resin modified polyurethane wet process resin.

[0066] The impregnation layer is prepared by weight of the following components: 2000-3000 parts of chloroacetic acid resin modified polyurethane wet-process resin, 4000-5000 parts of solvent, and 130-140 parts of non-woven fabric.

[0067] In the impregnation layer, the viscosity of the impregnation slurry at 25°C is 200–500 mPa·s, and the resin impregnation ratio is 30%–35%. The nonwoven fabric is selected from PET needle-punched nonwoven fabric or PET spunlace nonwoven fabric, with a thickness between 0.8 and 1.0 mm and a basis weight of 130–140 g / m². 2 between.

[0068] The impregnation layer is prepared by the following method:

[0069] Add chloroacetic acid resin-modified polyurethane wet-process resin and solvent, and disperse at a speed of 800-1000 r / min for 1-2 h until uniformly mixed; then degas under vacuum conditions of negative pressure 0.08-0.10 MPa for 2-3 h to obtain impregnation slurry; finally, mix nonwoven fabric and impregnation slurry evenly, place in DMF aqueous solution to solidify, wash with water, dry and shape to obtain impregnation layer.

[0070] The above-mentioned chlorinated vinyl acetate-modified polyurethane composite polishing pad is prepared by the following method, which includes the following steps:

[0071] Step 1: Dispersing the coating slurry. Add the chlorinated vinyl acetate modified polyurethane wet-process resin, color paste, nonionic surfactant, anionic surfactant and diluent to a container and disperse at a speed of 800-1000 r / min for 2-3 hours until the mixture is uniform to obtain the coating slurry.

[0072] Step 2: Degassing the coating slurry. Degas the evenly dispersed coating slurry under a negative pressure of 0.08-0.10 MPa for 3-4 hours. The viscosity of the coating slurry at 25°C is 10000-15000 mPa·s.

[0073] Step 3: Wet coating and coagulation. A layer of coating slurry obtained in Step 2 is coated on the impregnated layer. The wet film thickness of the coating slurry is 1.5-2.0 mm. The film is then placed in a DMF aqueous solution with a temperature of 25-45℃ and a mass concentration of 10%-30% for coagulation and foaming to obtain a coagulated sample.

[0074] Step 4: Washing and drying. Place the solidified sample in deionized water at 40-60℃ to wash off the solvent. Repeat this process more than 10 times until the solvent concentration is less than 1%. Then, dry the sample at 100-120℃ for 4-6 hours to set the sample.

[0075] Step 5: Grinding and hot pressing. Grind the shaped sample with 150-400 grit sandpaper to remove the dense layer on the surface of the coating layer and expose the upright cells. Then, hot press the pattern at a temperature of 120-140℃.

[0076] Step Six: Adhesive backing and cutting. The hot-pressed sample is adhesive backed and cut into round pieces to obtain the chlorinated vinyl resin modified polyurethane composite polishing pad.

[0077] Example 1

[0078] This embodiment provides a chloroacetic acid resin modified polyurethane composite polishing pad, which is prepared from the following raw materials and parts by weight: 1500 parts color paste, 30 parts nonionic surfactant, 30 parts anionic surfactant, 750 parts diluent, 315 parts backing adhesive, 3500 parts chloroacetic acid resin modified polyurethane wet-process resin, and 185 parts impregnation layer; the chloroacetic acid resin modified polyurethane composite polishing pad has a thickness of 1.5 mm, a 100% modulus of 14 MPa, a hardness of 52 Shore A, a compression ratio of 23%, a resilience of 92%, a pore size of 35 μm, and a porosity of 60%.

[0079] Preferably, the color paste is a carbon black paste with a solid content of 20 wt% and a median particle size of 120 nm; the nonionic surfactant is sorbitan monooleate (Span-80); the anionic surfactant is sodium docusate (OT-100); the diluent is N,N-dimethylformamide (DMF); and the adhesive is Sekisui Chemicals Co., Ltd. 560PSD with a thickness of 150 μm.

[0080] In this embodiment, the chloroacetic acid resin-modified polyurethane wet-process resin is synthesized from the following raw materials and parts by weight: 50 parts diisocyanate, 360 parts polyether diol, 10 parts aromatic diamine, 150 parts chloroacetic acid resin, 2 parts chain terminator, and 1300 parts diluent; the solid content of the chloroacetic acid resin-modified polyurethane wet-process resin is 30.6 wt%, the viscosity at 25°C is 180000 mPa·s, and the number-average molecular weight Mn is 135000.

[0081] Preferably, the diisocyanate is 4,4'-diphenylmethane diisocyanate (4,4-MDI), the polyether diol is polytetrahydrofuran diol (preferably PTMG-2000), the aromatic diamine is 4,4'-diaminodiphenylmethane (4,4-MDA), the vinyl chloride-vinyl acetate-vinyl alcohol copolymer has a hydroxyl value of 75 mg KOH / g and a molecular weight of 40,000, and the chain terminator is methanol.

[0082] In this embodiment, the synthesis method of chlorinated vinyl acetate modified polyurethane wet-process resin includes the following steps:

[0083] Step 1: Prepolymerization reaction. Polyether diol is dehydrated for 1 hour at 105-110℃ and negative pressure of 0.08-0.10MPa. Diisocyanate is added and prepolymerized at 80-90℃ for 2-3 hours to obtain isocyanate-terminated prepolymer.

[0084] Step 2: Chain extension reaction. Add diluent and aromatic diamine to the prepolymer in sequence to extend the chain, and maintain the reaction at 80-90℃ for 2-3 hours until the system solution polymerizes to a molecular weight between 60,000 and 80,000.

[0085] Step 3: Grafting reaction. Add chloroacetic acid resin to the above system and maintain the temperature at 80-90°C for 3-4 hours to perform the grafting reaction, chemically grafting the chloroacetic acid resin onto the polyurethane chain segments.

[0086] Step 4: Termination of reaction. When the grafting reaction of the above system reaches a number average molecular weight Mn of 120,000 to 150,000, add a chain terminator to terminate the reaction and discharge the material to obtain the chlorinated vinyl acetate resin modified polyurethane wet process resin.

[0087] In this embodiment, the impregnation layer is prepared from the following raw materials and parts by weight: 2500 parts of chloroacetic acid resin modified polyurethane wet process resin, 4500 parts of diluent solvent, and 135 parts of non-woven fabric; the impregnation slurry has a viscosity of 350 mPa·s at 25°C and a resin impregnation ratio of 33%.

[0088] Preferably, the nonwoven fabric is a PET needle-punched nonwoven fabric with a thickness of 0.9 mm and a basis weight of 135 g / m². 2 .

[0089] In this embodiment, the method for preparing the impregnation layer includes the following steps:

[0090] The chloroacetic acid resin-modified polyurethane wet-process resin and diluent are dispersed at a speed of 800-1000 r / min for 1-2 h until they are mixed evenly; then degassing is carried out under a negative pressure of 0.08-0.10 MPa for 2-3 h; finally, the nonwoven fabric and impregnation slurry are mixed and impregnated evenly, and then placed in DMF aqueous solution to solidify, wash with water, and dry to shape to obtain the impregnated layer.

[0091] The above-mentioned chloroacetic acid resin-modified polyurethane composite polishing pad was prepared by the following method. (Reference) Figure 1 The preparation method specifically includes the following steps, and the raw materials used in each step are as follows (by weight) in this embodiment:

[0092] Step 1: Disperse the coating slurry. Disperse the chloroacetic acid resin modified polyurethane wet process resin, color paste, surfactant, and diluent at a speed of 800-1000 r / min for 2-3 hours until the mixture is uniform.

[0093] Step 2: Degassing the coating slurry. The uniformly dispersed coating slurry is degassed under a vacuum of 0.08-0.10 MPa for 3-4 hours. The viscosity of the coating slurry at 25°C is 10000-15000 mPa·s.

[0094] Step 3: Wet coating and coagulation. A coating slurry with a wet film thickness of 1.5 to 2.0 mm is applied to the above impregnation layer and placed in a DMF aqueous solution with a temperature of 25 to 45°C and a concentration of 10% to 30% for coagulation and foaming.

[0095] Step 4: Washing and drying. Place the solidified sample in deionized water at 40-60°C to wash off the solvent. Repeat this process more than 10 times until the solvent concentration is less than 1%. Then, dry the sample at 100-120°C for 4-6 hours to set the solvent.

[0096] Step 5: Grinding and hot pressing. Grind the shaped sample with 150-400 grit sandpaper to remove the dense layer on the surface of the coating layer and expose the upright cells. Then, hot press the pattern at a temperature of 120-140℃.

[0097] Step Six: Adhesive backing and cutting. The hot-pressed sample is adhesive backed and cut into round pieces to obtain the chlorinated vinyl resin modified polyurethane composite polishing pad.

[0098] Please refer to the surface SEM images and cross-sectional SEM images of the chloroacetic acid resin modified polyurethane composite polishing pad prepared in this embodiment. Figure 1 and Figure 2 .

[0099] Example 2

[0100] This embodiment provides a chloroacetic acid resin modified polyurethane composite polishing pad, which is prepared from the following raw materials and parts by weight: 1000 parts color paste, 15 parts nonionic surfactant, 15 parts anionic surfactant, 500 parts diluent, 300 parts backing adhesive, 3000 parts chloroacetic acid resin modified polyurethane wet-process resin, and 170 parts impregnation layer; the chloroacetic acid resin modified polyurethane composite polishing pad has a thickness of 1.4 mm, a 100% modulus of 10 MPa, a hardness of 45 Shore A, a compression ratio of 30%, a resilience of 90%, a pore size of 30 μm, and a porosity of 40%.

[0101] Preferably, the color paste is titanium dioxide color paste with a solid content of 10 wt% and a median particle size of 100 nm; the nonionic surfactant is sorbitan monostearate (Span-60); the anionic surfactant is sodium dodecylbenzenesulfonate (SDBS); the diluent is N-methylpyrrolidone (NMP); and the adhesive is Sekisui Chemicals Co., Ltd. 568HM2 with a thickness of 100 μm.

[0102] In this embodiment, the chloroacetic acid resin modified polyurethane wet-process resin is synthesized from the following raw materials and parts by weight: 40 parts diisocyanate, 180 parts polyether diol, 5 parts aromatic diamine, 100 parts chloroacetic acid resin, 1 part chain terminator, and 605 parts diluent; its solid content is 35.0 wt%, its viscosity at 25°C is 150,000 mPa·s, and its number-average molecular weight Mn is 120,000.

[0103] Preferably, the diisocyanate is toluene-2,4-diisocyanate (2,4-TDI), the polyether diol is polypropylene glycol (preferably PPG-1000), the aromatic diamine is 2,4'-diaminodiphenylmethane (2,4-MDA), the vinyl chloride-vinyl acetate-vinyl alcohol copolymer has a hydroxyl value of 50 mg KOH / g and a molecular weight of 50,000, and the chain terminator is ethanol.

[0104] In this embodiment, the impregnation layer is prepared from the following raw materials and parts by weight: 2000 parts of chloroacetic acid resin modified polyurethane wet process resin, 5000 parts of diluent solvent, and 130 parts of non-woven fabric; the impregnation slurry has a viscosity of 200 mPa·s at 25°C and a resin impregnation ratio of 30%.

[0105] Preferably, the nonwoven fabric is a PET spunlace nonwoven fabric with a thickness of 0.8 mm and a basis weight of 130 g / m². 2 .

[0106] For the preparation methods of the chloroacetic acid resin modified polyurethane wet process resin, the preparation method of the impregnation layer, and the preparation method of the chloroacetic acid resin modified polyurethane composite polishing pad in this embodiment, please refer to Example 1; in the preparation process, the raw materials required for each step are calculated according to the weight parts of this embodiment.

[0107] Example 3

[0108] This embodiment provides a chloroacetic acid resin modified polyurethane composite polishing pad, which is prepared from the following raw materials and parts by weight: 2000 parts color paste, 45 parts nonionic surfactant, 45 parts anionic surfactant, 1000 parts diluent, 330 parts adhesive, 4000 parts chloroacetic acid resin modified polyurethane wet-process resin, and 200 parts impregnation layer; its thickness is 1.6 mm, 100% modulus is 12 MPa, hardness is 50 Shore A, compression ratio is 28%, resilience is 97%, pore size is 40 μm, and porosity is 46%.

[0109] Preferably, the color paste is a carbon black paste with a solid content of 30 wt% and a median particle size of 200 nm, the nonionic surfactant is sorbitan monostearate (Span-60), the anionic surfactant is sodium docusate (OT-100), the diluent is dimethyl sulfoxide (DMSO), and the adhesive is Sekisui Chemicals Co., Ltd. 5628C with a thickness of 200 μm.

[0110] In this embodiment, the chloroacetic acid resin modified polyurethane wet-process resin is synthesized from the following raw materials and parts by weight: 60 parts diisocyanate, 540 parts polyether diol, 15 parts aromatic diamine, 200 parts chloroacetic acid resin, 5 parts chain terminator, and 2460 parts diluent; its solid content is 25.0 wt%, its viscosity at 25°C is 200,000 mPa·s, and its number-average molecular weight Mn is 144,000.

[0111] Preferably, the diisocyanate is toluene-2,6-diisocyanate (2,6-TDI), the polyether diol is polypropylene glycol (preferably PPG-3000), the aromatic diamine is 2,6-diaminotoluene (2,6-TDA), the chloroacetic acid resin is vinyl chloride-vinyl acetate-vinyl alcohol copolymer with a hydroxyl value of 100 mg KOH / g and a molecular weight of 30,000, and the chain terminator is isopropanol.

[0112] In this embodiment, the impregnation layer is prepared from the following raw materials and parts by weight: 3000 parts of chloroacetic acid resin modified polyurethane wet process resin, 4000 parts of diluent solvent, and 140 parts of non-woven fabric; the impregnation slurry has a viscosity of 500 mPa·s at 25°C and a resin impregnation ratio of 35%.

[0113] Preferably, the nonwoven fabric is a PET spunlace nonwoven fabric with a thickness of 1.0 mm and a basis weight of 140 g / m². 2 .

[0114] For the preparation methods of the chloroacetic acid resin modified polyurethane wet process resin, the preparation method of the impregnation layer, and the preparation method of the chloroacetic acid resin modified polyurethane composite polishing pad in this embodiment, please refer to Example 1; in the preparation process, the raw materials required for each step are calculated according to the weight parts of this embodiment.

[0115] Example 4

[0116] This embodiment provides a chloroacetic acid resin modified polyurethane composite polishing pad, which is prepared from the following raw materials and parts by weight: 1600 parts color paste, 33 parts nonionic surfactant, 33 parts anionic surfactant, 800 parts diluent, 310 parts backing adhesive, 3600 parts chloroacetic acid resin modified polyurethane wet-process resin, and 180 parts impregnation layer; its thickness is 1.5 mm, 100% modulus is 15 MPa, hardness is 55 Shore A, compression ratio is 20%, resilience is 100%, pore size is 36 μm, and porosity is 55%.

[0117] Preferably, the color paste is titanium dioxide color paste with a solid content of 30wt% and a median particle size of 200nm, the nonionic surfactant is sorbitan monooleate (Span-80), the anionic surfactant is sodium dodecylbenzenesulfonate (SDBS), the diluent is N,N-dimethylformamide (DMF), and the adhesive is Sekisui Chemicals Co., Ltd. 560PSD with a thickness of 180μm.

[0118] In this embodiment, the chloroacetic acid resin modified polyurethane wet-process resin is synthesized from the following raw materials and parts by weight: 55 parts diisocyanate, 330 parts polyether diol, 12 parts aromatic diamine, 160 parts chloroacetic acid resin, 3 parts chain terminator, and 1240 parts diluent; its solid content is 31.1 wt%, its viscosity at 25°C is 175000 mPa·s, and its number-average molecular weight Mn is 150000.

[0119] Preferably, the diisocyanate is 2,4'-diphenylmethane diisocyanate (2,4-MDI), the polyether diol is polytetrahydrofuran diol (preferably PTMG-1000), the aromatic diamine is 2,4-diaminotoluene (2,4-TDA), the chloroacetic acid resin is vinyl chloride-vinyl acetate-vinyl alcohol copolymer with a hydroxyl value of 70 mg KOH / g and a molecular weight of 45,000, and the chain terminator is methanol.

[0120] In this embodiment, the impregnation layer is prepared from the following raw materials and parts by weight: 2600 parts of chloroacetic acid resin modified polyurethane wet process resin, 4400 parts of diluent solvent, and 133 parts of non-woven fabric; the impregnation slurry has a viscosity of 300 mPa·s at 25°C and a resin impregnation ratio of 32%.

[0121] Preferably, the nonwoven fabric is a PET needle-punched nonwoven fabric with a thickness of 0.9 mm and a basis weight of 133 g / m². 2 .

[0122] For the preparation methods of the chloroacetic acid resin modified polyurethane wet process resin, the preparation method of the impregnation layer, and the preparation method of the chloroacetic acid resin modified polyurethane composite polishing pad in this embodiment, please refer to Example 1; in the preparation process, the raw materials required for each step are calculated according to the weight parts of this embodiment.

[0123] Comparative Example 1

[0124] The only difference between Comparative Example 1 and Example 1 is that, in the synthesis of wet-process resin, the raw materials were replaced with polytetrahydrofuran diol (PTMG-2000) in equal parts by weight of chloroacetic acid resin. All other aspects remained the same as in Example 1.

[0125] Comparative Example 2

[0126] The only difference between Comparative Example 2 and Example 1 is that in the raw materials for preparing the polishing pad, the impregnation layer is replaced by an equal weight of PET (polyethylene terephthalate) film with a thickness of 0.188 mm. All other aspects are the same as in Example 1.

[0127] Test case

[0128] The physical properties and polishing performance of the chloroacetic acid resin-modified polyurethane composite polishing pads prepared in Examples 1-4 and the polishing pads prepared in Comparative Examples 1-2 were tested. Among them:

[0129] The test method for number-average molecular weight Mn refers to the national standard GB / T 27843-2011, and the gel permeation chromatograph (GPC) model is Agilent 1260 Infinity II.

[0130] The resin impregnation ratio is calculated using the following formula: RIR = (M1 - M0) / M1 × 100%, where M0 is the mass of the nonwoven fabric and M1 is the mass of the impregnation layer.

[0131] The test method for 100% modulus refers to the national standard GB / T 1040.3-2006, and the electronic universal testing machine model is ZwickRoll 5kN Allround table top.

[0132] The hardness test method refers to the national standard GB / T 2411-2008, and the Shore A hardness tester model is Teclock GS-709G.

[0133] The test methods for compression ratio and rebound rate refer to GB / T 30709-2014. The Dynamic Thermomechanical Analyzer (DMA) model is TA DMA850.

[0134] The test method for abrasion resistance is in accordance with GB / T 5478-2008, and the abrasion testing machine model is Taber 1700.

[0135] The test methods for pore size and porosity refer to the national standard GB / T 21650.1-2008, and the pore size analyzer model is MicroActive AutoPore V 9600.

[0136] The liquid carrying rate (LCR) is calculated using the following formula: LCR = (M1 - M0) / M0 × 100%, where M0 is the mass of the polishing pad before liquid loading and M1 is the mass of the polishing pad after liquid loading.

[0137] The testing methods for polishing removal rate, lifespan, surface roughness, and surface defects are as follows:

[0138] Remove the release paper from the 30-inch polishing pad sample and attach it to the CMP machine. The polishing fluid is Anji-D3000 with a flow rate of 300cc / min. The wafer is a 12-inch Teos Wafer. The CMP machine is Universal-300B with a pressure of 1.3psi, a grinding head speed of 70rpm, a grinding disc speed of 75rpm, and a dressing disc of Blue Brush.

[0139] The removal rate is an average value calculated by recording the removal rate during the polishing process using a four-probe film thickness gauge (KLA Filmetrics R50).

[0140] Surface roughness was measured using a 3D surface profiler (CHOTEST Superview W1).

[0141] The number of surface defects is the total number of wafer surface defects larger than 100nm detected by the defect analysis system (AMAT SEMVision G7).

[0142] Lifetime is the limit of time during which the polishing pad is continuously subjected to chemical mechanical polishing (CMP) tests until the polishing removal rate decreases significantly.

[0143] The physical properties and polishing performance of the chloroacetic acid resin modified polyurethane composite polishing pads prepared in Examples 1-4 and the polishing pads prepared in Comparative Examples 1-2 are shown in Table 1.

[0144] Table 1. Physical properties and polishing performance test results of the polishing pads prepared in Examples 1-2

[0145]

[0146]

[0147] Based on the test results of the above embodiments and comparative examples regarding the physical properties and polishing performance of the polishing pads:

[0148] Compared with the chloroacetic acid resin-modified polyurethane composite polishing pads prepared in Comparative Examples 1, 1 to 4, the polyurethane modified by side linking of chloroacetic acid resin makes the chain segment structure of wet-process resin more diversified, which can effectively increase the upper limit of number-average molecular weight and significantly improve its wear resistance (reduced wear) and mechanical properties (100% modulus and increased hardness). The polishing pads prepared have high removal rate and long service life.

[0149] In the chloroacetic acid resin modified polyurethane composite polishing pads prepared in Examples 1-4, the chloroacetic acid resin modified polyurethane wet process resin segments have abundant unreacted hydroxyl groups, which helps to promote the formation of more uniform water droplet-shaped cells and increase their porosity in the wet foaming process, thereby increasing the liquid carrying capacity and polishing removal rate.

[0150] Compared to Comparative Example 2, in the chloroacetic acid resin modified polyurethane composite polishing pads prepared in Examples 1-4, the synthesized wet-process resin and non-woven fabric are used as an impregnation layer to replace the PET film as the polishing pad buffer layer. This can effectively improve the compression ratio and resilience of the polishing pad, and in the CMP fine polishing process, it can improve the flatness of the wafer (reduced roughness) and reduce the surface defect rate (reduced number of defects).

[0151] The above description is merely an example and illustration of the structure of this invention, and while the description is specific and detailed, it should not be construed as limiting the scope of this invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this invention, and these obvious substitutions all fall within the protection scope of this invention.

Claims

1. A chlorinated vinyl acetate-modified polyurethane composite polishing pad, characterized in that, It is prepared from the following components in parts by weight: Color paste 1000~2000 parts, nonionic surfactant 15~45 parts, anionic surfactant 15~45 parts, diluent 500~1000 parts, adhesive 300~330 parts, chlorinated vinyl acetate modified polyurethane wet process resin 3000~4000 parts, impregnation layer 170~200 parts. The chloroacetic acid resin modified polyurethane wet process resin is prepared by the following components in parts by weight: 40-60 parts of diisocyanate, 180-540 parts of polyether diol, 5-15 parts of aromatic diamine, 100-200 parts of chloroacetic acid resin, 1-5 parts of chain terminator, and 605-2460 parts of solvent. The chloroacetic acid resin is a copolymer of vinyl chloride-vinyl acetate-vinyl alcohol, with a hydroxyl value between 50 and 100 mg KOH / g and a molecular weight between 30,000 and 50,000. The chlorinated vinyl acetate-modified polyurethane wet-process resin is prepared by the following method: Prepolymerization reaction: Polyether diol is dehydrated for 1 hour at 105~110℃ and negative pressure 0.08~0.10Mpa, and diisocyanate is added and prepolymerized at 80~90℃ for 2~3 hours to obtain isocyanate-terminated prepolymer. Chain extension reaction: a solvent and an aromatic diamine are added sequentially to the obtained prepolymer to extend the chain, and the reaction is maintained at 80~90℃ for 2~3h until the system solution polymerizes to a molecular weight between 60000~80000. Grafting reaction: Add chloroacetic acid resin and maintain the grafting reaction at 80~90℃ for 3~4 hours to chemically graft the chloroacetic acid resin onto the polyurethane chain segment. The reaction was terminated when the grafting reaction reached a number average molecular weight Mn between 120,000 and 150,000. A chain terminator was then added to terminate the reaction, and the product was discharged to obtain a chlorinated vinyl acetate-modified polyurethane wet-process resin.

2. The chloroacetic acid resin modified polyurethane composite polishing pad according to claim 1, characterized in that, The diisocyanate includes at least one of toluene-2,4-diisocyanate, toluene-2,6-diisocyanate, 4,4'-diphenylmethane diisocyanate, or 2,4'-diphenylmethane diisocyanate.

3. The chloroacetic acid resin modified polyurethane composite polishing pad according to claim 1, characterized in that, The polyether diol is at least one of polytetrahydrofuran diol or polypropylene glycol; wherein the polytetrahydrofuran diol is PTMG-1000, PTMG-2000 or PTMG-3000, and the polypropylene glycol is PPG-1000, PPG-2000 or PPG-3000.

4. The chloroacetic acid resin modified polyurethane composite polishing pad according to claim 1, characterized in that, The aromatic diamine includes at least one of 4,4'-diaminodiphenylmethane, 2,4'-diaminodiphenylmethane, 2,4-diaminotoluene, or 2,6-diaminotoluene; The chain terminator is methanol, ethanol, or isopropanol.

5. The chloroacetic acid resin modified polyurethane composite polishing pad according to claim 1, characterized in that, The color paste is either carbon black paste or titanium dioxide paste; The nonionic surfactant is sorbitan monostearate or sorbitan monooleate. The anionic surfactant is sodium docusate or sodium dodecylbenzene sulfonate. The diluent is N,N-dimethylformamide, N-methylpyrrolidone, or dimethyl sulfoxide; The adhesive backing is a pressure-sensitive acrylic adhesive, with models 568HM2, 560PSD, or 5628C, and a thickness between 100 and 200 μm.

6. The chloroacetic acid resin modified polyurethane composite polishing pad according to claim 1, characterized in that, The impregnation layer is prepared by weight of the following components: 2000-3000 parts of chloroacetic acid resin modified polyurethane wet process resin, 4000-5000 parts of solvent, and 130-140 parts of non-woven fabric.

7. The chloroacetic acid resin modified polyurethane composite polishing pad according to claim 6, characterized in that, In the impregnation layer, the viscosity of the impregnation slurry at 25°C is 200~500 mPa·s, and the resin impregnation ratio is 30%~35%; The nonwoven fabric includes PET needle-punched nonwoven fabric or PET spunlace nonwoven fabric, and the thickness of the nonwoven fabric is between 0.8 and 1.0 mm, and the basis weight is between 130 and 140 g / m². 2 between.

8. The chloroacetic acid resin modified polyurethane composite polishing pad according to claim 6, characterized in that, The impregnation layer is prepared by the following method: Add chloroacetic acid resin-modified polyurethane wet-process resin and solvent, and disperse at a speed of 800~1000 r / min for 1~2 h until uniformly mixed; then degas under vacuum conditions of negative pressure 0.08~0.10 MPa for 2~3 h to obtain impregnation slurry; finally, mix nonwoven fabric and impregnation slurry evenly, place in DMF aqueous solution to solidify, wash with water, dry and shape to obtain impregnation layer.

9. A method for preparing a chlorinated vinyl acetate resin-modified polyurethane composite polishing pad, used to prepare the chlorinated vinyl acetate resin-modified polyurethane composite polishing pad according to any one of claims 1-8, characterized in that, Includes the following steps: Step 1: Dispersing the coating slurry. Add the chlorinated vinyl acetate modified polyurethane wet-process resin, color paste, nonionic surfactant, anionic surfactant and diluent to a container and disperse at a speed of 800~1000 r / min for 2~3 hours until the mixture is uniform to obtain the coating slurry. Step 2: Degassing the coating slurry. Degas the evenly dispersed coating slurry under a negative pressure of 0.08~0.10 MPa for 3~4 hours. The viscosity of the coating slurry at 25℃ is 10000~15000 mPa·S. Step 3: Wet coating and coagulation. A layer of coating slurry obtained in Step 2 is coated on the impregnation layer. The wet film thickness of the coating slurry is 1.5~2.0mm. It is then placed in a DMF aqueous solution with a temperature of 25~45℃ and a mass concentration of 10%~30% for coagulation and foaming to obtain a coagulated sample. Step 4: Washing and drying. Place the solidified sample in deionized water at 40-60℃ to wash off the solvent. Repeat this process more than 10 times until the solvent concentration is less than 1%. Then, dry the sample at 100-120℃ for 4-6 hours to set the sample. Step 5: Grinding and hot pressing. Grind the shaped sample with 150~400 grit sandpaper to remove the dense layer on the surface of the coating layer and expose the upright cells. Then, hot press the pattern at a temperature of 120~140℃. Step Six: Adhesive backing and cutting. The hot-pressed sample is adhesive backed and cut into round pieces to obtain the chlorinated vinyl resin modified polyurethane composite polishing pad.

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