Polishing layer, polishing pad and polishing method

Abstract

The present invention provides a polishing layer, which is a uniform closed-cell elastomer formed from a polyurethane substrate having pores separating the continuous substrate, the polishing layer surface comprising microprotrusions that substantially contact the article being polished to form microscale contact areas, the polishing layer having a microscale contact area ratio between the polishing layer and the article being polished of between 0.01% and 5% at a pressure of between 1 psi and 20 psi. Controlling the microscale contact area ratio between the polishing layer and the article being polished to within the above range provides good polishing rates, low defect rates, and low polishing rate non-uniformity, and is suitable for use in a variety of semiconductor processes.

Description

Technical Field

[0001] This invention relates to the field of polishing technology for chemical mechanical planarization, and more specifically, to a polishing pad and a method for manufacturing semiconductor devices. Background Technology

[0002] CMP (Continuous Polishing) technology involves placing the workpiece surface downwards and applying pressure to a polishing pad. Under the action of the polishing fluid, and with the relative movement between the polishing pad and the workpiece, the material on the surface of the workpiece is removed through the mechanical grinding of the abrasive particles and the chemical corrosion of the oxidant, thereby obtaining a flat surface.

[0003] With the development of the semiconductor industry, the trend in processing technology is shifting towards higher current densities, higher clock frequencies, and more interconnect layers. Due to the shrinking size of the chips and the reduction in the depth of focus of lithography equipment, the required flatness of the chip surface to achieve a resolution at the nanometer level is necessary. Traditional planarization techniques, such as selective deposition based on deposition technology, SOG sputtering, low-pressure CVD, and plasma-enhanced CVD, can also provide smooth surfaces, but these are all local planarization techniques and cannot achieve global planarization. Currently, it is generally accepted internationally that when the feature size of a device is below 0.35μm, global planarization must be performed to ensure the accuracy and resolution of lithographic influence transfer. CMP technology is currently the only internationally recognized technology that can achieve global planarization, and CMP yield significantly affects chip yield.

[0004] Polishing pads, as one of the final consumables in CMP (Chemical Mechanical Polishing), are widely used in integrated circuit manufacturing. Currently used polishing pads are mainly made of polymer materials, with foamed and cured polyurethane as their primary component. These polishing pads not only have a certain density of micro-protrusions on their surface but also many hollow micropores. Their surface structure characteristics (roughness, groove shape, etc.) and material properties (hardness, elastic modulus, etc.) are all important factors affecting CMP. In practical applications, the surface roughness of the polishing pad often changes significantly with material consumption, and the microscopic contact area between the polishing pad and the workpiece also affects the CMP polishing process.

[0005] There is an urgent need to develop a polishing pad that is suitable for various manufacturing processes and has controllable micro-contact area and surface roughness. Summary of the Invention

[0006] To address the problems in the prior art, the first aspect of the present invention provides a polishing layer, wherein the polishing layer is a uniform closed-cell elastomer formed from a polyurethane substrate with continuous pore spacing, the surface of the polishing layer includes micro-protrusions, the micro-protrusions are in substantial contact with the object being polished to form a micro-contact surface, and the micro-contact area ratio between the polishing layer and the object being polished is between 0.01% and 5% under a pressure of 1 psi to 20 psi.

[0007] Furthermore, under a pressure of 1 psi to 10 psi, the contact coefficient ζ of the polishing layer is (microscopic contact area ratio between the polishing layer and the workpiece / density of the polishing layer) * 100, and the contact coefficient ζ is between 0.1 and 1.2.

[0008] As a preferred embodiment, under a pressure of 1psi to 5psi, the contact coefficient ζ of the polishing layer is (microscopic contact area ratio between the polishing layer and the workpiece / density of the polishing layer) * 100, and the contact coefficient ζ is between 0.1 and 0.7.

[0009] Furthermore, the roughness of the polished layer is between 1 μm and 30 μm;

[0010] Preferably, the roughness of the polished layer is between 2 μm and 15 μm;

[0011] Furthermore, the density of the polished layer is between 0.4 g / cm³. 3 ~1.1g / cm 3 The hardness of the polished layer is between 10D and 75D.

[0012] Furthermore, the polishing layer comprises a reaction product of an isocyanate-terminated prepolymer and a curing agent, wherein the isocyanate-terminated prepolymer comprises a reaction product of a polyfunctional isocyanate and a polyol.

[0013] Furthermore, the polyfunctional isocyanate comprises one or more combinations of 2,4-toluene diisocyanate, 2,6-toluene diisocyanate, 2,2'-diphenylmethane diisocyanate, 2,4'-diphenylmethane diisocyanate, 4,4'-diphenylmethane diisocyanate, 1,5-naphthalene diisocyanate, terephthalic diisocyanate, isophthalic diisocyanate, terephthalimide diisocyanate, isophthalimide diisocyanate, ethylene diisocyanate, 2,2,4-trimethylhexamethylene diisocyanate, 1,6-hexamethylene diisocyanate, 1,4-cyclohexane diisocyanate, 4,4'-dicyclohexylmethane diisocyanate, isophorone diisocyanate, and norbornene diisocyanate;

[0014] Preferably, the polyfunctional isocyanate comprises one or more combinations of 2,4-toluene diisocyanate, 2,6-toluene diisocyanate, and 4,4'-dicyclohexylmethane diisocyanate;

[0015] Furthermore, the polyol comprises one or more combinations of homopolymers and / or copolymers of polytetramethylene ether glycol, polyethylene glycol, polypropylene glycol, ethylene glycol, butanediol, diethylene glycol, neopentyl glycol, 2-methyl-1,3-propanediol, hexanediol, 3-methyl-1,5-pentanediol, 1,4-cyclohexanediol, ethylene oxide, and propylene oxide;

[0016] Preferably, the polyol comprises one or more combinations of homopolymers and / or copolymers of polytetramethylene ether glycol, polypropylene glycol, diethylene glycol, ethylene oxide, and propylene oxide;

[0017] Furthermore, the curing agent comprises a polyamine curing agent;

[0018] The polyamine curing agent comprises diethyltoluenediamine (DETDA), N,N'-dialkyldiaminodiphenylmethane, 3,5-diethyl-2,4-toluenediamine and its isomers (e.g., 3,5-diethyl-2,6-toluenediamine), 3,5-dimethylthio-2,4-toluenediamine and its isomers, 4,4'-methylene-bis-(2-chloroaniline) (MOCA), 4,4'-bis-(sec-butylamino)-diphenylmethane, 1,4-bis-(sec-butylamino)-benzene, 4,4'-methylene-bis-(2-chloroaniline), 4,4'-methylene-bis- (3-Chloro-2,6-diethylaniline) (MCDEA), polytetramethylene-di-p-aminobenzoate; p,p'-methylenebisaniline (MDA); m-phenylenediamine (MPDA); 4,4'-methylene-di-(2,6-diethylaniline) (MDEA), 4,4'-methylene-di-(2,3-dichloroaniline) (MDCA), 4,4'-diamino-3,3'-diethyl-5,5'-dimethyldiphenylmethane, 2,2',3,3'-tetrachlorodiaminodiphenylmethane, propylene glycol-di-p-aminobenzoate (one or more combinations thereof);

[0019] Particularly preferred is the polyamine curing agent 4,4'-methylene-bis-(2-chloroaniline) (MOCA);

[0020] Furthermore, the unreacted NCO content of the isocyanate-terminated prepolymer is between 8.0% and 9.5%, and the stoichiometric ratio of NH2 to NCO in the isocyanate-terminated prepolymer is between 80% and 105%.

[0021] A second aspect of the present invention provides a polishing pad comprising the polishing layer described above, and further comprising an intermediate adhesive layer, a buffer layer, and a release film layer. Under a pressure of 1 psi to 20 psi, the microscopic contact area ratio between the polishing pad and the workpiece being polished is between 0.01% and 5%.

[0022] A third aspect of the present invention provides a polishing method, providing a polished object selected from at least one of a magnetic substrate, an optical substrate, or a semiconductor substrate, providing the aforementioned polishing pad, forming dynamic contact between the polishing surface of the polishing layer and the polished object, thereby polishing the surface of the polished object, and using a dressing tool to trim the polished surface.

[0023] This invention prepares a polishing pad by controlling the microscopic contact area between the polishing layer and the workpiece within a certain range. This polishing pad can achieve a good polishing rate and a low defect rate during the polishing of semiconductor devices. Furthermore, by controlling the contact coefficient ζ within a certain range, the non-uniformity of the polishing rate can be effectively improved. This polishing pad is suitable for various semiconductor manufacturing processes. Attached Figure Description

[0024] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0025] Figure 1 This invention relates to a microscopic cross-section of the polishing layer and a schematic diagram of the contact surface with the object being polished.

[0026] Figure 2 A schematic diagram illustrating the application of the polishing pad provided in an embodiment of the present invention;

[0027] Figure 3 This is a schematic diagram of the polishing pad provided in an embodiment of the present invention;

[0028] Figure 4 This is a schematic diagram of sampling for measuring the micro-contact area ratio of a polishing pad or polishing layer in an embodiment of the present invention.

[0029] 1-Material to be polished; 2-Polishing pad; 3-Polishing machine; 4-Support; 5-Polishing liquid; 20-Polishing layer; 21-Adhesive layer; 22-Backing adhesive layer; 23-Buffer layer; 201-Micro-protrusion; 202-Contact area; 203-Contact surface. Detailed Implementation

[0030] The present invention provides a polishing layer, which is a uniform closed-cell elastomer formed from a polyurethane substrate with continuous pore spacing. The surface of the polishing layer includes micro-protrusions, which are in substantial contact with the object being polished to form a micro-contact surface. Under a pressure of 1 psi to 20 psi, the micro-contact area ratio between the polishing layer and the object being polished is between 0.01% and 5%.

[0031] Since the polishing layer is made of polyurethane, its surface often exhibits a certain degree of roughness and unevenness relative to the surface of the object being polished. This surface characteristic means that when the rough peaks of the polishing layer come into contact with the object being polished, the two are not in a completely adhered state, and local contact points will be formed. The number and size of local contact points will affect the polishing rate. Therefore, the micro-contact area ratio involved in this invention is the proportion of the actual contact area between the polishing layer and the object being polished to the area of ​​the polishing layer under certain pressure conditions. Since the polyurethane material in this invention is homogeneous, the micro-contact area ratio of the polishing layer can be used to reflect the micro-contact area ratio of the entire polishing layer.

[0032] As a method for measuring the micro-contact area ratio, conventional testing methods in this field can be selected.

[0033] As an example of a testing method, the present invention can be performed using the following method:

[0034] To prepare samples for micro-contact area ratio testing, first wipe the surface of the polishing pad or polishing layer with anhydrous ethanol, then dry it with a drying device. Use a mold with a diameter of 10mm to 20mm to cut out circles with a diameter of 10mm to 20mm from the polishing pad or polishing layer to be tested. When sampling, ensure that the samples are taken from the same area. After sample preparation, observe whether the sample surface is flat. You can take the area with grooves or without grooves on the surface of the polishing pad or polishing layer. It should be noted that the area with grooves or without grooves is different. When taking the area with grooves, the area of ​​the grooves needs to be deducted in the data processing. The grooves are carriers for the abrasive composition and polishing debris. They do not actually come into contact with the polished object in the polishing process. Therefore, when calculating the actual micro-contact area ratio, the projected area of ​​the grooves should also be deducted.

[0035] Microscopic contact area ratio sampling: Take 14-20 sets of photos on the surface of a circular test sample with a diameter of 10mm-20mm. Preferably, select 6 sets of photos from the center of the circular test sample and 4 sets from each side, for a total of 14 sets of photos. Calculate the average of the calculated microscopic contact area ratios to estimate the overall microscopic contact ratio of the polishing pad or polishing layer. Figure 4 As shown.

[0036] Motion device: The Z-axis of the test system uses a Taiwan GMT standard electric slide table (AXS60-A2NR-DD) with a travel of ±10mm, a table size of 60mm*60mm, and a unidirectional positioning accuracy of 15μm. The motion control unit uses a combination of an SMC30 PLC controller and an SMC72XL Hall control lever; the sensor uses an S-type force sensor (SMT1-10N, INTERFACEUSA).

[0037] Optical setup: Inverted metallurgical microscope (LC-230DZ, Shenzhen Licheng Instrument Co., Ltd.).

[0038] Software algorithm: The micro-contact measurement software for polishing pads based on MATLAB 2020a is used to calculate the micro-contact area ratio after analyzing the images captured by the metallographic microscope.

[0039] The above-described test method is merely one of many test methods in this field. This invention does not limit the scope of the invention. It should be understood that any test method that can implement this invention can be applied to this invention.

[0040] Preferably, in this embodiment of the invention, for the purpose of polishing process application, the microscopic contact area ratio between the polishing layer and the polished object is between 0.1% and 1% under a pressure of 1psi to 17psi.

[0041] Preferably, in this embodiment of the invention, for the sake of appropriate pressure in the polishing process, the microscopic contact area ratio between the polishing layer and the polished object is between 0.1% and 0.6% under a pressure of 1 psi to 10 psi.

[0042] Preferably, in the embodiments of the present invention, considering the appropriate polishing process and suitable pressure, as well as a high removal rate and relatively few defects, the microscopic contact area ratio between the polishing layer and the polished object is between 0.4% and 0.5% under a pressure of 9 psi to 10 psi.

[0043] Preferably, in this embodiment of the invention, for the sake of minimal defects, the microscopic contact area ratio between the polishing layer and the polished object is between 0.5% and 0.8% under a pressure of 9 psi to 10 psi.

[0044] Preferably, in this embodiment of the invention, for the sake of extremely high removal rate, the microscopic contact area ratio between the polishing layer and the polished object is between 0.3% and 0.4% under a pressure of 9 psi to 10 psi.

[0045] In this invention, considering the need for lower grinding rate uniformity, the contact coefficient ζ of the polishing layer under a pressure of 1psi to 10psi is between 0.1 and 1.2, which is equal to (microscopic contact area ratio between the polishing layer and the workpiece / density of the polishing layer) * 100.

[0046] Preferably, in this invention, considering the need for lower grinding rate uniformity, the contact coefficient ζ of the polishing layer under a pressure of 1psi to 5psi is (microscopic contact area ratio between the polishing layer and the workpiece / density of the polishing layer) * 100, and the contact coefficient ζ is between 0.1 and 0.7.

[0047] In the embodiments of the present invention, the roughness of the polishing layer is between 1 μm and 30 μm; preferably, in the embodiments of the present invention, the roughness of the polishing layer is between 2 μm and 15 μm.

[0048] For the sake of appropriate polishing process pressure, as well as high removal rate and relatively few defects, it is particularly preferred that the roughness of the polished layer in the embodiments of the present invention is between 8 μm and 10 μm.

[0049] For the sake of minimal defects, it is particularly preferred that the roughness of the polished layer in the embodiments of the present invention is between 10 μm and 15 μm.

[0050] For the sake of extremely high removal rate, it is particularly preferred that the roughness of the polishing layer in the embodiments of the present invention is between 2μm and 8μm.

[0051] The density of the polished layer in this embodiment of the invention is between 0.4 g / cm³. 3 ~1.1g / cm 3 The hardness of the polished layer is between 10D and 75D.

[0052] Preferably, in the embodiments of the present invention, the density of the polished layer is between 0.5 g / cm³. 3 ~0.9g / cm 3 In particular, in embodiments of the present invention, the density of the polished layer is between 0.7 g / cm³. 3 ~0.9g / cm 3 between.

[0053] Preferably, in the embodiments of the present invention, the hardness of the polishing layer is between 40D and 70D; more preferably, in the embodiments of the present invention, the hardness of the polishing layer is between 55D and 70D.

[0054] The polishing layer in this invention comprises the reaction product of an isocyanate-terminated prepolymer and a curing agent, wherein the isocyanate-terminated prepolymer comprises the reaction product of a polyfunctional isocyanate and a polyol.

[0055] Polyfunctional isocyanates

[0056] In the embodiments of the present invention, the polyfunctional isocyanate includes, but is not limited to, one or more combinations of aromatic isocyanates or aliphatic isocyanates, preferably using more than 80 mol% aromatic isocyanates, more preferably using more than 95 mol% aromatic isocyanates, and particularly preferably using 100 mol% aromatic isocyanates.

[0057] Aromatic isocyanates include one or more combinations of 2,4-toluene diisocyanate, 2,6-toluene diisocyanate, 2,2'-diphenylmethane diisocyanate, 2,4'-diphenylmethane diisocyanate, 4,4'-diphenylmethane diisocyanate, 1,5-naphthalene diisocyanate, terephthalic diisocyanate, isophthalic diisocyanate, terephthalimide diisocyanate, and isophthalimide diisocyanate.

[0058] Aliphatic isocyanates include one or more combinations of ethylene diisocyanate, 2,2,4-trimethylhexamethylene diisocyanate, 1,6-hexamethylene diisocyanate, 1,4-cyclohexane diisocyanate, 4,4'-dicyclohexylmethane diisocyanate, isophorone diisocyanate, and norbornene diisocyanate.

[0059] In this embodiment of the invention, considering the reactivity and physical properties of the polished layer, one or more combinations of 2,4-toluene diisocyanate, 2,6-toluene diisocyanate, 2,2'-diphenylmethane diisocyanate, 2,4'-diphenylmethane diisocyanate, 4,4'-diphenylmethane diisocyanate, and 4,4'-dicyclohexylmethane diisocyanate are preferably used.

[0060] In this embodiment of the invention, considering the reactivity and physical properties of the polishing pad, it is particularly preferred to use one or a combination of two of 2,4-toluene diisocyanate, 2,6-toluene diisocyanate, and 4,4-dicyclohexylmethane diisocyanate.

[0061] polyols

[0062] In the embodiments of the present invention, the polyol may include polyether-based high molecular weight diols, wherein the polyether-based high molecular weight diols include, but are not limited to, polytetramethylene ether glycol (PTMEG), polyethylene glycol (PEG), polypropylene glycol (PPG), and one or more combinations of homopolymers and / or copolymers of polytetramethylene ether glycol-polyethylene glycol, polytetramethylene ether glycol-polypropylene glycol, polyethylene glycol-polypropylene glycol, ethylene oxide, and propylene oxide, or high molecular weight polyols formed by homopolymerization or copolymerization of ethylene glycol, propylene glycol, butanediol, or an initiator having two hydroxyl groups with the above three small molecular weight diols, or a combination of multiple compositions.

[0063] In the embodiments of the present invention, the polyol may include small molecule diols, wherein the small molecules include, but are not limited to, one or more combinations of ethylene glycol, butanediol, diethylene glycol, neopentyl glycol, 2-methyl-1,3-propanediol, hexanediol, 3-methyl-1,5-pentanediol, and 1,4-cyclohexanediethanol.

[0064] In the embodiments of the present invention, the polyol composition may further comprise a polyester-based polyol, wherein the polyester-based polyol is obtained by a condensation reaction of a diol or a diol / phenol with a diacid, wherein the diol includes one or more combinations of ethylene glycol, 1,3-butanediol, 1,4-butanediol, diethylene glycol, neopentyl glycol, 2-methyl-1,3-propanediol, hexanediol, 3-methyl-1,5-pentanediol, and 1,4-cyclohexanediol, preferably, the diol includes 1,4-Butanediol, hexanediol, or a combination thereof; the diol / phenol is hydroquinone, resorcinol, naphthol, bisphenol A, bisphenol S, terephthalic acid, isophthalic acid, o-phthalic acid, 2,5-furandiol, terephthalic acid, or diphenyl ether diol, preferably, the diol / phenol is hydroquinone, terephthalic acid, or a combination thereof; the diacid is succinic acid, adipic acid, azelaic acid, sebacic acid, or a combination thereof.

[0065] In this embodiment of the invention, considering the reactivity and physical properties of the polishing pad, it is preferable to use one or more combinations of polytetramethylene ether glycol (PTMEG), diethylene glycol, butanediol, or homopolymers and / or copolymers of ethylene oxide and propylene oxide.

[0066] In this embodiment of the invention, considering the reactivity and physical properties of the polishing pad, it is particularly preferred to use one or a combination of polytetramethylene ether glycol (PTMEG) and diethylene glycol.

[0067] The isocyanate-terminated prepolymers described above can be obtained by reacting the aforementioned polyfunctional isocyanates with polyols, or by purchasing commercially available prepolymer products.

[0068] Commercially available isocyanate-terminated prepolymers include, but are not limited to, any one or more combinations of the following series of prepolymers manufactured by Chemtura: LF800A, LF900A, LF910A, LF930A, LF931A, LF939A, LF950A, LF952A, LF600D, LF601D, LF650D, L42, L325, L100, L150, L167, L200, L275, L300, L310, L367, L480, L500, LF667, LF667D, LF700D, LF750D, LF751D, LF752D, LF753D, LFG963A, LFG964A, and LFG740D.

[0069] curing agent

[0070] In the embodiments of the present invention, the curing agent is selected from one or more combinations of polyamine curing agents or polyol curing agents. The present invention does not particularly limit the polyamine curing agent or polyol curing agent, and it can be any suitable aromatic bifunctional curing agent or polyol curing agent in the art.

[0071] Examples of polyamine curing agents that can be used in the embodiments of the present invention include diethyltoluenediamine (DETDA), N,N'-dialkyldiaminodiphenylmethane, 3,5-diethyl-2,4-toluenediamine and its isomers (e.g., 3,5-diethyl-2,6-toluenediamine), 3,5-dimethylthio-2,4-toluenediamine and its isomers, 4,4'-methylene-bis-(2-chloroaniline) (MOCA), 4,4'-bis-(sec-butylamino)-diphenylmethane, 1,4-bis-(sec-butylamino)-benzene, 4,4'-methylene-bis-(2-chloroaniline), 4,4'- Methylene-bis-(3-chloro-2,6-diethylaniline) (M-CDEA), polytetramethylene-di-p-aminobenzoate; p,p'-methylenebisaniline (MDA); m-phenylenediamine (MPDA); 4,4'-methylene-di-(2,6-diethylaniline) (MDEA), 4,4'-methylene-di-(2,3-dichloroaniline) (MDCA), 4,4'-diamino-3,3'-diethyl-5,5'-dimethyldiphenylmethane, 2,2',3,3'-tetrachlorodiaminodiphenylmethane, propylene glycol-di-p-aminobenzoate, or one or more combinations thereof.

[0072] To ensure a suitable working time during polishing pad preparation and to ensure that the resulting polishing pad has good polishing performance, the polyamine curing agent preferably comprises one or a combination of 4,4'-methylene-bis-(2-chloroaniline) (MOCA) and 4,4'-methylene-bis-(3-chloro-2,6-diethylaniline) (M-CDEA); particularly preferably, the polyamine curing agent comprises 4,4'-methylene-bis-(2-chloroaniline) (MOCA).

[0073] Hollow microsphere polymer

[0074] In the polishing layer preparation process, hollow microsphere polymers are usually uniformly dispersed in the polishing layer to adjust the polishing effect of the polishing layer.

[0075] In this invention, the term "hollow microsphere polymer" refers to an expandable hollow polymer microsphere that expands moderately during curing due to the temperature rise caused by the exothermic reaction. By adjusting the distribution (e.g., density) of the hollow microsphere polymer in the polyurethane polishing layer and combining this with adjusting the particle size of the hollow microsphere polymer, the polishing performance of the polishing layer can be further adjusted. Preferably, the hollow microsphere polymer dispersion in the polishing layer results in a final porosity of 10% to 65%.

[0076] Preferably, the hollow microsphere polymer includes, but is not limited to, a capsule structure with an outer wall of polyacrylonitrile and polyacrylonitrile copolymer, and can be purchased from any one of AkzoNobel, Matsumoto Yushi Pharmaceutical Co., Ltd. or Sekisui Chemicals Co., Ltd. In particular, in the embodiments of the present invention, AkzoNobel hollow microspheres or Matsumoto microspheres F series are selected.

[0077] In the embodiments of the present invention, the unreacted NCO content of the isocyanate-terminated prepolymer is between 8.0% and 9.5%, preferably between 8.5% and 9.5% in the isocyanate-terminated prepolymer.

[0078] In the embodiments of the present invention, the stoichiometric ratio of NCO in the isocyanate-terminated prepolymer of the curing agent containing NH2 or / and OH is between 80% and 105%; preferably, the stoichiometric ratio of NCO in the isocyanate-terminated prepolymer of the curing agent containing NH2 or / and OH is between 80% and 100%.

[0079] The polishing pad involved in this invention includes the aforementioned polishing layer. In addition, the polishing pad also includes an intermediate adhesive layer, a buffer layer, and a release film layer. Under pressure conditions of 1 psi to 20 psi, the microscopic contact area ratio between the polishing pad and the workpiece being polished is between 0.01% and 5%. Figure 2 The polishing pad shown includes a polishing layer 20, an intermediate adhesive layer 21, a buffer layer 22, and a release film layer 23. After the polishing layer is bonded to the buffer layer and the release film layer, the micro-contact area ratio of the polishing pad relative to the polishing layer will increase slightly.

[0080] In this invention, appropriate modifiers may be added to the polyurethane substrate to achieve even better overall performance improvements. Preferably, these modifiers can modify at least one property of the polished layer, including but not limited to the group consisting of: porosity, rigidity, surface energy, abrasion resistance, conductivity, and chemical functionality. Modifying materials include, but are not limited to: antioxidants, lubricants, pigments, fillers, anti-static agents, etc.

[0081] In this invention, the polishing layer may be provided with grooves as is customary in the art, and these grooves are used to receive polishing fluid during the polishing process. The grooves can be obtained by processing after the polishing layer is formed. The grooves ensure the smooth discharge and flow of the polishing fluid used during the polishing process. Preferably, the grooves are one or more of the following: concentric circular grooves (e.g., annular or spiral grooves), curved grooves, grid grooves, regular polygonal grooves (e.g., hexagonal, triangular), and tire tread patterns. Particularly preferred are one or more of the following: annular grooves, spiral grooves, X-Y grid grooves, hexagonal grooves, triangular grooves, and fractal grooves. Particularly preferred are the following: the cross-section of the groove is one or more of the following: a rectangular groove with straight sidewalls, a "V" shape, a "U" shape, and a serrated shape.

[0082] Optional features include a trench width of 0.1–0.6 mm, a trench depth of 0.5–0.9 mm, a trench spacing of 2–5 mm between adjacent trenches, and the option to include or exclude a central blank area, wherein the radius of the central blank area is 50 mm–150 mm.

[0083] In CMP (Chemical Mechanical Polishing), a buffer layer is needed to balance the trade-offs of flatness and uniformity. Flatness refers to the smoothness of the patterned area when polishing a material with minute irregularities created during pattern formation, while uniformity refers to the overall uniformity of the polished material. Flatness is improved by utilizing the properties of the polishing layer, and uniformity is improved by utilizing the properties of the buffer layer. In the polishing pad of this invention, the buffer layer is preferably made of a material softer than the polishing layer.

[0084] Examples of buffer layers include: polyester nonwoven fabric, nylon nonwoven fabric, acrylonitrile nonwoven fabric and other fiber nonwoven fabrics, resin-impregnated nonwoven fabrics such as polyester nonwoven fabric impregnated with polyurethane, high molecular resin foams such as polyurethane foam and polyethylene foam, rubbery resins such as butadiene rubber and isoprene rubber, and photosensitive resins.

[0085] As a method for bonding the polishing layer and the buffer layer, an intermediate adhesive is used. The intermediate adhesive can be double-sided tape, and the polishing layer and the buffer layer are placed on both sides of the intermediate adhesive and pressed together.

[0086] The polishing pad of the present invention also includes an adhesive backing layer, which can also be double-sided tape. Examples of components of the adhesive backing layer include rubber-based adhesives and acrylic adhesives. Considering the metal ion content, acrylic adhesives have a low metal ion content and are therefore preferred.

[0087] In this invention, the adhesive layer also includes a release film or release paper. The polishing pad can be bonded to the polishing machine by peeling off the release film or release paper before use.

[0088] In this embodiment of the invention, the polishing layer can be provided with an endpoint detection window as needed. Optionally, at least one endpoint detection area can be formed in the polishing layer. During polishing, the endpoint detection area of ​​the polishing layer can perform high-precision optical endpoint detection, and the detection method can be optical detection. By making the endpoint detection area with a suitable material, it can have appropriate light transmittance to observe the polished object (such as a silicon wafer). As a preferred embodiment, the material forming the endpoint detection area has a light transmittance of not less than 20% in the entire wavelength range of 300 to 800 nm. More preferably, the light transmittance of the high-transmittance material is not less than 60%.

[0089] As a preferred option, the material of the endpoint detection area includes, but is not limited to, thermosetting resins such as polyurethane resin, polyester resin, phenolic resin, urea resin, melamine resin, epoxy resin, and acrylic resin; one or more combinations of thermoplastic resins such as polyurethane resin, polyester resin, polyamide resin, cellulose resin, acrylic resin, polycarbonate resin, halogenated resins (polyvinyl chloride, polytetrafluoroethylene, and polyvinylidene fluoride, etc.), polystyrene, and olefin resins (polyethylene, polypropylene, etc.).

[0090] Polishing

[0091] The polishing pads involved in this invention can be applied to common semiconductor manufacturing processes. Examples of common processes include, but are not limited to: STI process, Oxide process, W process, Al process, Copper process, and Poly process.

[0092] Polishing treatment: using, for example Figure 1 The polishing apparatus shown includes a polishing stage 3 supporting a polishing pad 2, a backing material for uniformly pressurizing a support 4 supporting the semiconductor wafer 1 to be polished, and a polishing slurry supply mechanism. The polishing pad 2 is attached to the polishing stage 3, for example, by adhesive adhesion. The polishing stage 3 and the support 4 are configured such that the polishing pad 2 and the semiconductor wafer 1 they support face each other, and each has a rotation axis. Additionally, a pressure mechanism is provided on one side of the support 4 for pressing the semiconductor wafer 1 onto the polishing pad 2. During polishing, the polishing stage 3 and the support 4 are rotated, pressing the semiconductor wafer 1 onto the polishing pad 2, and polishing is performed while slurry is supplied. The slurry flow rate, polishing load, polishing stage speed, and wafer speed are not particularly limited and can be adjusted appropriately.

[0093] The polishing method of the present invention provides a workpiece to be polished, which is selected from at least one of a magnetic substrate, an optical substrate or a semiconductor substrate, provides the above-mentioned polishing pad, forms dynamic contact between the polishing surface of the polishing layer and the workpiece to be polished, thereby polishing the surface of the workpiece, and uses a dressing tool to trim the polished surface.

[0094] Example

[0095] The embodiments of the present invention will be described in detail below with reference to examples. However, those skilled in the art will understand that the following examples are for illustrative purposes only and should not be considered as limiting the scope of the invention. Unless otherwise specified in the examples, conventional conditions or conditions recommended by the manufacturer are followed. Reagents or instruments whose manufacturers are not specified are all commercially available conventional products.

[0096] Explanation of reference numerals in the embodiments:

[0097] LF750D and LFG963A: These represent Chemtura Corporation's... LF750D isocyanate-terminated prepolymer; LFG963A isocyanate-terminated prepolymer; LF667 isocyanate-terminated prepolymer;

[0098] MOCA: 4,4'-methylene-bis-(2-chloroaniline);

[0099] DEG: Diethylene glycol;

[0100] TDI: Toluene diisocyanate;

[0101] HMDI: 4,4'-dicyclohexylmethane diisocyanate;

[0102] PTMEG: Polytetramethylene ether glycol;

[0103] 920DE 40d30: Nouryon 920DE 40d30, average particle size 40μm, density 0.03g / cm³ 3 ;

[0104] 920DET 40d25: Nouryon 920DET 40d25, average particle size 40μm, density 0.025g / cm³ 3 ;

[0105] 920DE 80d30: Nouryon 920DE 80d30, average particle size 80μm, density 0.03g / cm³ 3 ;

[0106] 043DET 80d20: Nouryon 043DET 80d20, average particle size 80μm, density 0.02g / cm³ 3 ;

[0107] The raw materials mentioned above that do not specify the source of the trademarks are all from commercially available bulk industrial products, and the manufacturers include BASF, Covestro, Wanhua Chemical, Suzhou Xiangyuan, Chizhou Tinci, Mitsui Chemicals, Mitsubishi Chemical, etc.

[0108] Example 1

[0109] This embodiment provides a polishing pad, the preparation method of which is as follows:

[0110] Step 1: React 37.70 parts by mass of TDI, 1.57 parts by mass of HMDI, 54.85 parts by mass of PTMEG1000, and 5.88 parts by mass of DEG to obtain an isocyanate-terminated prepolymer. Heat to 25–65°C and degas under vacuum (-0.095 MPa) for 2 hours to remove gases and small molecule compounds from the prepolymer. Then add 1.34 parts by mass of hollow microsphere polymer 920DE 40d30 and stir to uniformly disperse the hollow microsphere polymer in the prepolymer. Degas again under vacuum (-0.095 MPa) for 2 hours. The unreacted NCO content in the isocyanate-terminated prepolymer is 9.4%.

[0111] Step 2: Heat 26.08 parts by mass of MOCA to 115°C and set aside. The stoichiometric ratio of NH2 in MOCA to NCO in the isocyanate-terminated prepolymer is 87%.

[0112] Step 3: Mix the prepolymer and curing agent under high-speed shearing, then pour the mixture into a circular mold to form a 12cm thick casting block. Let it stand at room temperature for 10 minutes, then place it in a 100℃ oven to cure for 16 hours. After curing, allow it to automatically cool to room temperature in the oven, and then cut it into 80mil thick sheets.

[0113] Step 4: Select a groove shape that uses concentric circular grooves with a blank (ungrooved) area in the center. The grooving parameters are: groove depth 30mil, groove width 20mil, groove spacing 120mil, and the diameter of the blank area in the center is 5 inches. After grooving, the polishing layer T1 is formed.

[0114] Step 5: For the intermediate adhesive and backing adhesive layer, double-sided tape (purchased from Sekisui Chemicals and 3M) is used. The intermediate adhesive is used to bond the polishing layer T1 to the buffer layer, and the backing adhesive layer is bonded to the other side of the buffer layer (the side where the polishing layer is not bonded) to obtain the polishing pad P1. The buffer layer is made of polyurethane impregnated non-woven fabric (SUBA IV).

[0115] Example 2

[0116] This embodiment provides a polishing pad, the preparation method of which is as follows:

[0117] Step 1: React 32.55 parts by mass of TDI, 8.1 parts by mass of HMDI, 57.35 parts by mass of PTMEG650, and 5.88 parts by mass of DEG to obtain an isocyanate-terminated prepolymer. Heat to 25–65°C and degas under vacuum (-0.095 MPa) for 2 hours to remove gases and small molecule compounds from the prepolymer. Then add 1.97 parts by mass of hollow microsphere polymer 920DE 40d30 and stir to uniformly disperse the hollow microsphere polymer in the prepolymer. Degas again under vacuum (-0.095 MPa) for 2 hours. The unreacted NCO content in the isocyanate-terminated prepolymer is 9.3%.

[0118] Step 2: Heat 25.73 parts by mass of MOCA to 115°C and set aside. The stoichiometric ratio of NH2 in MOCA to NCO in the isocyanate-terminated prepolymer is 87%.

[0119] Step 3: Mix the prepolymer and curing agent under high-speed shearing, then pour the mixture into a circular mold to form a 12cm thick casting block. Let it stand at room temperature for 10 minutes, then place it in a 100℃ oven to cure for 16 hours. After curing, allow it to automatically cool to room temperature in the oven, and then cut it into 80mil thick sheets.

[0120] Step 4: Select a groove shape that uses concentric circular grooves with a blank (ungrooved) area in the center. The grooving parameters are: groove depth 30mil, groove width 20mil, groove spacing 120mil, and the diameter of the blank area in the center is 5 inches. After grooving, the polishing layer T2 is formed.

[0121] Step 5: For the intermediate adhesive and backing adhesive layer, double-sided tape (purchased from Sekisui Chemicals and 3M) is used. The intermediate adhesive is used to bond the polishing layer T2 to the buffer layer, and the backing adhesive layer is bonded to the other side of the buffer layer (the side where the polishing layer is not bonded) to obtain the polishing pad P2. The buffer layer is made of polyurethane impregnated non-woven fabric (SUBA IV).

[0122] Example 3

[0123] This embodiment provides a polishing pad, the preparation method of which is as follows:

[0124] Step 1: React 32.98 parts by mass of TDI, 8.54 parts by mass of HMDI, 56.13 parts by mass of PTMEG650, and 2.35 parts by mass of DEG to obtain an isocyanate-terminated prepolymer. Heat to 25–65°C and degas under vacuum (-0.095 MPa) for 2 hours to remove gases and small molecule compounds from the prepolymer. Then add 3.63 parts by mass of hollow microsphere polymer 920DET 40d25 and stir to uniformly disperse the hollow microsphere polymer in the prepolymer. Degas again under vacuum (-0.095 MPa) for 2 hours. The unreacted NCO content in the isocyanate-terminated prepolymer is 9.5%.

[0125] Step 2: Heat 26.36 parts by mass of MOCA to 115°C and set aside. The stoichiometric ratio of NH2 in MOCA to NCO in the isocyanate-terminated prepolymer is 87%.

[0126] Step 3: Mix the prepolymer and curing agent under high-speed shearing, then pour the mixture into a circular mold to form a 12cm thick casting block. Let it stand at room temperature for 10 minutes, then place it in a 100℃ oven to cure for 16 hours. After curing, allow it to automatically cool to room temperature in the oven, and then cut it into 80mil thick sheets.

[0127] Step 4: Select a groove shape that uses concentric circular grooves with a blank (ungrooved) area in the center. The grooving parameters are: groove depth 30mil, groove width 20mil, groove spacing 120mil, and the diameter of the blank area in the center is 5 inches. After grooving, the polishing layer T3 is formed.

[0128] Step 5: For the intermediate adhesive and backing adhesive layer, double-sided tape (purchased from Sekisui Chemicals and 3M) is used. The intermediate adhesive is used to bond the polishing layer T3 to the buffer layer, and the backing adhesive layer is bonded to the other side of the buffer layer (the side where the polishing layer is not bonded). This will give you the polishing pad P3. The buffer layer is made of polyurethane-impregnated non-woven fabric (SUBA IV).

[0129] Example 4

[0130] This embodiment provides a polishing pad, the preparation method of which is as follows:

[0131] Step 1: React 38.01 parts by mass of TDI, 1.97 parts by mass of HMDI, 54.08 parts by mass of PTMEG1000, and 5.94 parts by mass of DEG to obtain an isocyanate-terminated prepolymer. Heat to 25–65°C and degas under vacuum (-0.095 MPa) for 2 hours to remove gases and small molecule compounds from the prepolymer. Then add 1.29 parts by mass of hollow microsphere polymer 920DE 80d30 and stir to uniformly disperse the hollow microsphere polymer in the prepolymer. Degas again under vacuum (-0.095 MPa) for 2 hours. The unreacted NCO content in the isocyanate-terminated prepolymer is 9.7%.

[0132] Step 2: Heat 26.90 parts by mass of MOCA to 115°C and set aside. The stoichiometric ratio of NH2 in MOCA to NCO in the isocyanate-terminated prepolymer is 87%.

[0133] Step 3: Mix the prepolymer and curing agent under high-speed shearing, then pour the mixture into a circular mold to form a 12cm thick casting block. Let it stand at room temperature for 10 minutes, then place it in a 100℃ oven to cure for 16 hours. After curing, allow it to automatically cool to room temperature in the oven, and then cut it into 80mil thick sheets.

[0134] Step 4: Select a groove shape that uses concentric circular grooves with a blank (ungrooved) area in the center. The grooving parameters are: groove depth 30mil, groove width 20mil, groove spacing 120mil, and the diameter of the blank area in the center is 5 inches. After grooving, the polishing layer T4 is formed.

[0135] Step 5: For the intermediate adhesive and backing adhesive layer, double-sided tape (purchased from Sekisui Chemicals and 3M) is used. The intermediate adhesive is used to bond the polishing layer T4 to the buffer layer, and the backing adhesive layer is bonded to the other side of the buffer layer (the side where the polishing layer is not bonded). This will give you the polishing pad P4. The buffer layer is made of polyurethane-impregnated non-woven fabric (SUBA IV).

[0136] Example 5

[0137] This embodiment provides a polishing pad, the preparation method of which is as follows:

[0138] Step 1: React 31.95 parts by mass of TDI, 8.40 parts by mass of HMDI, 57.88 parts by mass of PTMEG650, and 1.77 parts by mass of DEG to obtain an isocyanate-terminated prepolymer. Heat to 25–65°C and degas under vacuum (-0.095 MPa) for 2 hours to remove gases and small molecule compounds from the prepolymer. Then add 0.83 parts by mass of hollow microsphere polymer 043DET 80d20 and stir to uniformly disperse the hollow microsphere polymer in the prepolymer. Degas again under vacuum (-0.095 MPa) for 2 hours. The unreacted NCO content in the isocyanate-terminated prepolymer is 9.2%.

[0139] Step 2: Heat 30.79 parts by mass of MOCA to 115°C and set aside. The stoichiometric ratio of NH2 in MOCA to NCO in the isocyanate-terminated prepolymer is 105%.

[0140] Step 3: Mix the prepolymer and curing agent under high-speed shearing, then pour the mixture into a circular mold to form a 12cm thick casting block. Let it stand at room temperature for 10 minutes, then place it in a 100℃ oven to cure for 16 hours. After curing, allow it to automatically cool to room temperature in the oven, and then cut it into 80mil thick sheets.

[0141] Step 4: Select a groove shape that uses concentric circular grooves with a blank (ungrooved) area in the center. The grooving parameters are: groove depth 30mil, groove width 20mil, groove spacing 120mil, and the diameter of the blank area in the center is 5 inches. After grooving, the polishing layer T5 is formed.

[0142] Step 5: For the intermediate adhesive and backing adhesive layer, use double-sided tape (purchased from Sekisui Chemicals and 3M). Use the intermediate adhesive to bond the polishing layer T5 to the buffer layer, and then bond the backing adhesive layer to the other side of the buffer layer (the side where the polishing layer is not bonded). This will give you the polishing pad P5. The buffer layer is made of polyurethane-impregnated non-woven fabric (SUBA IV).

[0143] Example 6

[0144] This embodiment provides a polishing pad, the preparation method of which is as follows:

[0145] Step 1: React 39.34 parts by mass of TDI, 54.85 parts by mass of PTMEG1000, and 5.81 parts by mass of DEG to obtain an isocyanate-terminated prepolymer. Heat to 25–65°C and degas under vacuum (-0.095 MPa) for 2 hours to remove gases and small molecule compounds from the prepolymer. Then add 0.46 parts by mass of hollow microsphere polymer 920DE40d30 and stir to uniformly disperse the hollow microsphere polymer in the prepolymer. Degas again under vacuum (-0.095 MPa) for 2 hours. The unreacted NCO content in the isocyanate-terminated prepolymer is 9.8%.

[0146] Step 2: Heat 32.62 parts by mass of MOCA to 115°C and set aside. The stoichiometric ratio of NH2 in MOCA to NCO in the isocyanate-terminated prepolymer is 105%.

[0147] Step 3: Mix the prepolymer and curing agent under high-speed shearing, then pour the mixture into a circular mold to form a 12cm thick casting block. Let it stand at room temperature for 10 minutes, then place it in a 100℃ oven to cure for 16 hours. After curing, allow it to automatically cool to room temperature in the oven, and then cut it into 80mil thick sheets.

[0148] Step 4: Select a groove shape that uses concentric circular grooves with a blank (ungrooved) area in the center. The grooving parameters are: groove depth 30mil, groove width 20mil, groove spacing 120mil, and the diameter of the blank area in the center is 5 inches. After grooving, the polishing layer T6 is formed.

[0149] Step 5: For the intermediate adhesive and backing adhesive layer, use double-sided tape (purchased from Sekisui Chemicals and 3M). Use the intermediate adhesive to bond the polishing layer T6 to the buffer layer, and then bond the backing adhesive layer to the other side of the buffer layer (the side where the polishing layer is not bonded). This will give you the polishing pad P6. The buffer layer is made of polyurethane-impregnated non-woven fabric (SUBA IV).

[0150] Example 7

[0151] This embodiment provides a polishing pad, the preparation method of which is as follows:

[0152] Step 1: React 32.98 parts by mass of TDI, 8.54 parts by mass of HMDI, 56.13 parts by mass of PTMEG650, and 2.35 parts by mass of DEG to obtain an isocyanate-terminated prepolymer. Heat to 25–65°C and degas under vacuum (-0.095 MPa) for 2 hours to remove gases and small molecule compounds from the prepolymer. Then add 3.02 parts by mass of hollow microsphere polymer 920DE 40d30 and stir to uniformly disperse the hollow microsphere polymer in the prepolymer. Degas again under vacuum (-0.095 MPa) for 2 hours. The unreacted NCO content in the isocyanate-terminated prepolymer is 9.5%.

[0153] Step 2: Heat 26.36 parts by mass of MOCA to 115°C and set aside. The stoichiometric ratio of NH2 in MOCA to NCO in the isocyanate-terminated prepolymer is 87%.

[0154] Step 3: Mix the prepolymer and curing agent under high-speed shearing, then pour the mixture into a circular mold to form a 12cm thick casting block. Let it stand at room temperature for 10 minutes, then place it in a 100℃ oven to cure for 16 hours. After curing, allow it to automatically cool to room temperature in the oven, and then cut it into 80mil thick sheets.

[0155] Step 4: Select a groove shape that uses concentric circular grooves with a blank (ungrooved) area in the center. The grooving parameters are: groove depth 30mil, groove width 20mil, groove spacing 120mil, and the diameter of the blank area in the center is 5 inches. After grooving, the polishing layer T7 is formed.

[0156] Step 5: For the intermediate adhesive and backing adhesive layer, double-sided tape (purchased from Sekisui Chemicals and 3M) is used. The intermediate adhesive is used to bond the polishing layer T7 to the buffer layer, and the backing adhesive layer is bonded to the other side of the buffer layer (the side where the polishing layer is not bonded). This will give you the polishing pad P7. The buffer layer is made of polyurethane-impregnated non-woven fabric (SUBA IV).

[0157] Example 8

[0158] This embodiment provides a polishing pad, which is prepared by the following method:

[0159] Step 1: Take 76.5 parts by weight LF750D isocyanate-terminated prepolymer with 23.5 parts by weight The isocyanate-terminated prepolymer of LFG963A was mixed and heated to 25–65°C, then degassed under vacuum (-0.095 MPa) for 2 hours. Then, 0.59 parts by weight of hollow microsphere polymer 920DE 40d30 were added, and the mixture was stirred to ensure uniform dispersion of the hollow microsphere polymer in the prepolymer. The mixture was then degassed again under vacuum (-0.095 MPa) for 2 hours and set aside for later use. The unreacted NCO content in the isocyanate-terminated prepolymer was 8.3%.

[0160] Step 2: Maintain the curing agent composition (MOCA 23.49 parts by weight) at 115°C for later use. The stoichiometric ratio of NH2 in MOCA to NCO in the isocyanate-terminated prepolymer is 89%.

[0161] Step 3: Mix the prepolymer and curing agent composition under high-speed shearing, then pour it into a circular mold to form a 12cm thick casting block. Let it stand at room temperature for 10 minutes, then place it in a 100℃ oven to cure for 16 hours. After curing, allow it to automatically cool to room temperature in the oven, and then cut it into sheets with thicknesses of 80mil, 50mil, and 120mil.

[0162] Step 4: Select a thin sheet with a thickness of 80mil. Choose a groove shape that uses concentric circular grooves with a blank (ungrooved) area in the center. The grooving parameters are: groove depth 30mil, groove width 20mil, groove spacing 120mil, and the diameter of the blank area in the center is 5 inches. After grooving, the polished layer T8 is formed.

[0163] Step 5: For the intermediate adhesive and backing adhesive layer, use double-sided tape (purchased from Sekisui Chemicals and 3M). Use the intermediate adhesive to bond the polishing layer T8 to the buffer layer, and then bond the backing adhesive layer to the other side of the buffer layer (the side without the polishing layer). This will give you the polishing pad P8. The buffer layer is made of polyurethane-impregnated non-woven fabric (SUBA).

[0164] Comparative Example 1

[0165] This comparative example provides a polishing pad, which is prepared by the following method:

[0166] Step 1: Take 100 parts by weight The isocyanate-terminated prepolymer of LFG963A was heated to 25–65°C and degassed under vacuum (-0.095 MPa) for 2 hours. Then, 1.51 parts by weight of hollow microsphere polymer 920DE 40d30 were added, and the hollow microsphere polymer was uniformly dispersed in the prepolymer under stirring. The prepolymer was then degassed again under vacuum (-0.095 MPa) for 2 hours and set aside for use. The unreacted NCO content in the isocyanate-terminated prepolymer was 5.8%.

[0167] Step 2: Maintain the temperature at 115°C for the curing agent composition: MOCA 7.07 parts by weight and polyether polyol. HF505 (molecular weight 11400) 15.92 parts by weight and 800 (molecular weight 280) 5.31 parts by weight, kept at 25-65℃ for later use. Among them, MOCA contains NH2 and... 800 and The total OH groups of HF505 are stoichiometric in proportion to the NCO of the isocyanate-terminated prepolymer, which is 100%.

[0168] Step 3: Mix the prepolymer and curing agent composition under high-speed shearing, then cast it into a circular mold to form a 12cm thick casting block. Let it stand at room temperature for 10 minutes, then place it in a 100℃ oven to cure for 16 hours. After curing, allow it to automatically cool to room temperature in the oven, and then cut it into 80mil thick sheets.

[0169] Step 4: Select a thin sheet with a thickness of 80mil. Choose a groove shape that uses concentric circular grooves with a blank (ungrooved) area in the center. The grooving parameters are: groove depth 30mil, groove width 20mil, groove spacing 120mil, and the diameter of the blank area in the center is 5 inches. After grooving, it becomes the polishing layer TD1.

[0170] Step 5: For the intermediate adhesive and backing adhesive layer, use double-sided tape (purchased from Sekisui Chemicals and 3M). Use the intermediate adhesive to bond the polishing layer TD1 to the buffer layer, and then bond the backing adhesive layer to the other side of the buffer layer (the side where the polishing layer is not bonded). This will give you the polishing pad PD1. The buffer layer is made of polyurethane-impregnated non-woven fabric (SUBA).

[0171] Comparative Example 2

[0172] This comparative example provides a polishing pad, which is prepared by the following method:

[0173] Step 1: Take 100 parts by weight The isocyanate-terminated prepolymer of LF667 was heated to 25–65°C and degassed under vacuum (-0.095 MPa) for 2 hours. Then, 1.32 parts by weight of hollow microsphere polymer 920DE 40d30 were added, and the hollow microsphere polymer was uniformly dispersed in the prepolymer under stirring. The prepolymer was then degassed again under vacuum (-0.095 MPa) for 2 hours and set aside for later use. The unreacted NCO content in the isocyanate-terminated prepolymer was 6.2%.

[0174] Step 2: Prepare the curing agent composition: polyether polyol HF505 (molecular weight 11400) 55.93 parts by weight and 800 (molecular weight 280) 9.11 parts by weight, kept at 25-65℃ until use. Among them, MOCA contains NH2 and... 800 and The total OH groups of HF505 are stoichiometric in proportion to the NCO of the isocyanate-terminated prepolymer, which is 100%.

[0175] Step 3: Mix the prepolymer and curing agent composition under high-speed shearing, then cast it into a circular mold to form a 12cm thick casting block. Let it stand at room temperature for 10 minutes, then place it in a 100℃ oven to cure for 16 hours. After curing, allow it to automatically cool to room temperature in the oven, and then cut it into 80mil thick sheets.

[0176] Step 4: Select a thin sheet with a thickness of 80mil. Choose a groove shape that uses concentric circular grooves with a blank (ungrooved) area in the center. The grooving parameters are: groove depth 30mil, groove width 20mil, groove spacing 120mil, and the diameter of the blank area in the center is 5 inches. After grooving, it becomes the polishing layer TD2.

[0177] Step 5: For the intermediate adhesive and backing adhesive layer, use double-sided tape (purchased from Sekisui Chemicals and 3M). Use the intermediate adhesive to bond the polishing layer TD2 to the buffer layer, and then bond the backing adhesive layer to the other side of the buffer layer (the side without the polishing layer). This will give you the polishing pad PD2. The buffer layer is made of polyurethane-impregnated non-woven fabric (SUBA).

[0178] Shore hardness of polished layer

[0179] The REX digital Shore D-type automatic hardness tester and the Bareiss digital Shore D-type automatic hardness tester were used for measurement. The sample to be tested was punched into a 3"×3" square sample with a thickness of not less than 5mm. The measurement point was at least 9mm away from any edge of the sample, and the hardness value was measured at least 6mm apart on the same sample. The maximum value was recorded. The sample was tested in a standard environment of 23±2℃ and 50%±10% humidity. The specific results are shown in Table 1.

[0180] Density of polished layer

[0181] The calculation is performed using the following formula: SG=m / v=m / (π(d / 2)^2*h), where m is the weight of the polished layer, d is the diameter of the polished layer, and h is the thickness of the polished layer. See Table 1 for the specific results.

[0182] Evaluation of micro-contact area ratio

[0183] Sample preparation: Wipe the surface of the polishing pad or polishing layer with anhydrous ethanol, then dry it with an air gun. Use a 10mm diameter mold to cut out a 10mm diameter circle from the polishing pad or polishing layer to be tested. When sampling, ensure that the samples are taken from the same area. After sample preparation, observe whether the sample surface is flat. You can take samples from the grooved or non-grooved areas of the polishing pad or polishing layer surface. Note that when taking samples from the grooved areas, the area of ​​the grooves needs to be deducted during data processing.

[0184] Sampling: Take 14 photos on the surface of a 10mm circular test sample. You can select 6 photos from the center of the circular test sample and 4 photos from each of the left and right sides. Figure 4 As shown.

[0185] Sports equipment:

[0186] The Z-axis of the testing system uses a Taiwan GMT standard electric slide table (AXS60-A2NR-DD) with a travel of ±10mm, a table size of 60mm*60mm, and a unidirectional positioning accuracy of 15μm. The motion control unit uses a combination of an SMC30PLC controller and an SMC72XL Hall control lever. The sensor is an S-type force sensor (SMT1-10N, INTERFACE USA).

[0187] Optical devices:

[0188] Inverted metallurgical microscope (LC-230DZ, Shenzhen Licheng Instrument Co., Ltd.)

[0189] Software Algorithm:

[0190] The micro-contact ratio of polishing pads was calculated from images captured by a metallographic microscope using MATLAB 2020a-based software for measuring micro-contact of polishing pads. Specific results are shown in Tables 1 and 2.

[0191] In this embodiment of the invention, the micro-contact area of ​​the polishing pad or polishing layer was measured under three pressures: 1.85 psi, 9.25 psi, and 16.65 psi. Simultaneously, the micro-contact area ratio of the polishing pad or polishing layer after passing through the grinding machine was also measured. S11 (%) indicates the micro-contact area ratio of a 1.85psi polishing pad or polishing layer. S15 (%) indicates the micro-contact area ratio of a 9.25psi polishing pad or polishing layer. S19 (%) represents the micro-contact area ratio of a 16.65psi polishing pad or polishing layer; where, the micro-contact area ratio S21 (%) indicates the micro-contact area ratio of a 1.85psi polishing pad.S25 (%) indicates the micro-contact area ratio of the 9.25psi polishing pad. S29 (%) indicates the micro-contact area ratio of a 16.65psi polishing pad.

[0192] Polished layer roughness

[0193] Surface roughness was measured using a white light interferometer, where roughness (μm) represents the roughness of the polished layer. Specific results are shown in Table 1.

[0194] Table 1

[0195] serial number Polished layer <![CDATA[Density (g / cm 3 )]]> Shore hardness (D) Roughness (μm) <![CDATA[Microscopic contact area ratio S11 (%)]]> <![CDATA[Microscopic contact area ratio S15 (%)]]> <![CDATA[Microscopic contact area ratio S19 (%)]]> ζ(S11-1.85psi) ζ(S15-9.25psi) Example 1 T1 0.80 61.0 9.1 0.152 0.452 0.715 0.190 0.565 Example 2 T2 0.71 59.6 9.2 0.165 0.485 0.797 0.232 0.683 Example 3 T3 0.50 46.1 11.4 0.380 0.677 0.881 0.759 1.354 Example 4 T4 0.81 65.9 9.1 0.153 0.444 0.721 0.189 0.548 Example 5 T5 0.82 66.3 9.0 0.152 0.440 0.715 0.185 0.537 Example 6 T6 0.98 71.1 7.7 0.138 0.372 0.630 0.140 0.380 Example 7 T7 0.60 53.9 10.5 0.172 0.533 0.833 0.286 0.888 Example 8 T8 0.94 64.2 7.5 0.141 0.389 0.651 0.150 0.414 Comparative Example 1 TD1 0.75 19.2 4.9 2.872 3.417 5.214 3.829 4.556 Comparative Example 2 TD2 0.81 7.1 4.4 2.458 3.211 5.079 3.035 3.965

[0196] In Table 1, ζ(S11-1.85psi) represents the contact coefficient, which is 100 times the ratio of the micro-contact area ratio to the density of the polished layer under a pressure of 1.85psi; ζ(S15-9.25psi) represents the contact coefficient, which is 100 times the ratio of the micro-contact area ratio to the density of the polished layer under a pressure of 9.25psi.

[0197] Table 2

[0198] serial number Polishing pad <![CDATA[Microscopic contact area ratio S21 (%)]]> <![CDATA[Microscopic contact area ratio S25 (%)]]> <![CDATA[Microscopic contact area ratio S29 (%)]]> Example 1 P1 0.303 0.706 1.173 Example 2 P2 0.322 0.740 1.265 Example 3 P3 0.440 0.815 1.347 Example 4 P4 0.302 0.703 1.195 Example 5 P5 0.307 0.704 1.200 Example 6 P6 0.301 0.633 1.066 Example 7 P7 0.356 0.807 1.304 Example 8 P8 0.308 0.670 1.098 Comparative Example 1 PD1 4.150 5.875 8.336 Comparative Example 2 PD2 3.785 5.558 8.096

[0199] Polishing performance evaluation of polishing pads

[0200] The polishing pads used in the prepared examples and comparative examples were tested on a machine to evaluate their polishing performance. The test conditions are as follows:

[0201] The test equipment was an AMAT Refelxion (Modify 5Zone);

[0202] The polishing wafers were 300mm 3S20KTENTEOS (oxide) blanket-coated wafers purchased from Novellus Systems, Inc. The polishing slurry used was CES333F polishing fluid (purchased from Asahi Glass Company). Polishing conditions included a platen speed of 92 rpm, a carrier speed of 93 rpm, a slurry flow rate of 230 ml / min, and downforces of 12.8 kPa (1.85 psi) and 63.8 kPa (9.25 psi). An I-PDA31G-3N diamond adjustment disc (purchased from Kinik Company) was used to adjust the chemical mechanical polishing pad. The removal rate was measured using KLA-Tencor. The polishing pad's polishing performance was evaluated after grinding. The removal rate (TEOS) was... The grinding rate inhomogeneity (NU) is shown in Table 3 below, and the grinding rate inhomogeneity (%) is calculated for downpressures of 12.8 kPa (1.85 psi) and 63.8 kPa (9.25 psi).

[0203] Defect rating

[0204] Defects on the material after polishing the substrate can be obtained using KLA-Tencor. The SP2 defect inspection system was used to inspect the wafers. The defect size was 0.16 μm. The measurement was performed on the 10th wafer. The evaluation results are shown in Table 3.

[0205] Table 3

[0206]

[0207] It should be noted that, based on the explanations and descriptions in the foregoing specification, those skilled in the art can make changes and modifications to the above embodiments. Therefore, the present invention is not limited to the specific embodiments disclosed and described above, and some equivalent modifications and alterations to the present invention should also be within the scope of protection of the claims of the present invention. Furthermore, although some specific terms are used in this specification, these terms are only for convenience of explanation and do not constitute any limitation on the invention.

Claims

1. A polishing layer, characterized by, The polishing layer is a uniform closed-cell elastomer formed from a polyurethane substrate with continuous pore spacing. The surface of the polishing layer includes micro-protrusions that are in substantial contact with the object being polished to form a micro-contact surface. Under pressure conditions of 1 psi to 20 psi, the micro-contact area ratio between the polishing layer and the object being polished is between 0.01% and 5%.

2. The polishing layer of claim 1, wherein Under pressure conditions of 1psi to 10psi, the contact coefficient ζ of the polishing layer is (microscopic contact area ratio between the polishing layer and the polished object / density of the polishing layer) * 100, and the contact coefficient ζ is between 0.1 and 1.

2.

3. The polished layer according to claim 1, characterized in that, The roughness of the polished layer is between 1 μm and 30 μm.

4. The polished layer according to claim 1, characterized in that, The roughness of the polished layer is between 2μm and 15μm.

5. The polished layer according to claim 1, characterized in that, The density of the polishing layer is between 0.4 g / cm 3 ~ 1.1 g / cm 3 The hardness of the polishing layer is between 10D~75D.

6. The polished layer according to claim 1, characterized in that, The polished layer comprises the reaction product of an isocyanate-terminated prepolymer and a curing agent, wherein the isocyanate-terminated prepolymer comprises the reaction product of a polyfunctional isocyanate and a polyol.

7. The polished layer according to claim 6, characterized in that, The polyfunctional isocyanates comprise one or more combinations of 2,4-toluene diisocyanate, 2,6-toluene diisocyanate, 2,2'-diphenylmethane diisocyanate, 2,4'-diphenylmethane diisocyanate, 4,4'-diphenylmethane diisocyanate, 1,5-naphthalene diisocyanate, terephthalene diisocyanate, isophthalene diisocyanate, terephthalimide diisocyanate, isophthalimide diisocyanate, ethylidene diisocyanate, 2,2,4-trimethylhexamethylene diisocyanate, 1,6-hexamethylene diisocyanate, 1,4-cyclohexane diisocyanate, 4,4'-dicyclohexylmethane diisocyanate, isophorone diisocyanate, and norbornene diisocyanate.

8. The polished layer according to claim 6, characterized in that, The polyfunctional isocyanate comprises one or more combinations of 2,4-toluene diisocyanate, 2,6-toluene diisocyanate, and 4,4'-dicyclohexylmethane diisocyanate.

9. The polished layer according to claim 6, characterized in that, The polyol comprises one or more combinations of homopolymers and / or copolymers of polytetramethylene ether glycol, polyethylene glycol, polypropylene glycol, ethylene glycol, butanediol, diethylene glycol, neopentyl glycol, 2-methyl-1,3-propanediol, hexanediol, 3-methyl-1,5-pentanediol, 1,4-cyclohexanediol, ethylene oxide, and propylene oxide.

10. The polished layer according to claim 6, characterized in that, The polyol comprises one or more combinations of homopolymers and / or copolymers of polytetramethylene ether glycol, polypropylene glycol, diethylene glycol, ethylene oxide, and propylene oxide.

11. The polished layer according to claim 6, characterized in that, The curing agent comprises a polyamine curing agent; the polyamine curing agent comprises diethyltoluenediamine (DETDA), N,N'-dialkyldiaminodiphenylmethane, 3,5-diethyl-2,4-toluenediamine and its isomers, 3,5-dimethylthio-2,4-toluenediamine and its isomers, 4,4'-methylene-bis-(2-chloroaniline) (MOCA), 4,4'-bis-(sec-butylamino)-diphenylmethane, 1,4-bis-(sec-butylamino)-benzene, 4,4'-methylene-bis-(2-chloroaniline), 4,4'-methylene-bis-(3- Chloro-2,6-diethylaniline (MCDEA), polytetramethylene-di-p-aminobenzoate; p,p'-methylenebisaniline (MDA); m-phenylenediamine (MPDA); 4,4'-methylene-di-(2,6-diethylaniline) (MDEA), 4,4'-methylene-di-(2,3-dichloroaniline) (MDCA), 4,4'-diamino-3,3'-diethyl-5,5'-dimethyldiphenylmethane, 2,2',3,3'-tetrachlorodiaminodiphenylmethane, propylene glycol-di-p-aminobenzoate, or one or more combinations thereof.

12. The polished layer according to claim 11, characterized in that, The polyamine curing agent is 4,4'-methylene-bis-(2-chloroaniline) (MOCA).

13. The polished layer according to claim 6, characterized in that, The isocyanate-terminated prepolymer has an unreacted NCO content between 8.0% and 9.5%, and the isocyanate-terminated prepolymer has an NH2 to NCO stoichiometric ratio between 80% and 105%.

14. A polishing pad, characterized in that, The polishing pad comprises a polishing layer as described in any one of claims 1 to 13, an intermediate adhesive layer, a buffer layer, and a release film layer. Under a pressure of 1 psi to 20 psi, the microscopic contact area ratio between the polishing pad and the workpiece being polished is between 0.01% and 5%.

15. A polishing method, characterized in that, A polishable object is provided, the polishable object being selected from at least one of a magnetic substrate, an optical substrate, or a semiconductor substrate; a polishing pad as described in claim 14 is provided, forming a dynamic contact between the polishing surface of the polishing layer and the polishable object, thereby polishing the surface of the polishable object; and a dressing tool is used to trim the polished surface.

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