Formulations for high porosity chemical mechanical polishing pads with high hardness and cmp pads made therewith

Abstract

wt.%, based on the total solids weight of the aromatic isocyanate component, and (ii) a liquid polyol component including one or more curatives selected from the group of amines defined by Formulas (I) and (II).

Description

[Technical Field]

[0001] This invention relates to a two-component polyurethane composition for manufacturing chemical mechanical planarization polishing (CMP) pads having an unfilled Shore D hardness (2 seconds) of 57 to 77 or a filled Shore D hardness (2 seconds) of 18 to 50, a CMP polishing pad made therefrom, and a method for manufacturing the same. More specifically, this invention relates to a CMP polishing pad comprising a polyurethane foam reaction product of a two-component reaction mixture of a liquid aromatic diisocyanate component and a liquid polyol component, the liquid polyol component comprising one or more selected curing agents, the curing agents being hydroxyl-substituted aliphatic tertiary amines. [Previous Technology]

[0002] In CMP processes, polishing pads are combined with polishing solutions (such as abrasive-containing polishing slurries and / or non-abrasive reactive liquids) to remove excess material in a manner that planarizes or maintains the flatness of semiconductor, optical, or magnetic substrates. There is a continuous need for CMP polishing pads that combine increased layer uniformity or planarization performance with high removal rates. Increased CMP removal rates reduce polishing time and polishing solution consumption. Therefore, CMP pads with higher removal rates are desirable due to reduced device manufacturing costs. The removal rate (especially for Cu CMP) is affected by the hardness and porosity of the pad material.

[0003] U.S. Patent Application Publication No. 2019 / 0232460 discloses a polishing pad comprising thermoplastic polyurethane. The thermoplastic polyurethane having a tertiary amine is a reaction product of a polyurethane reaction containing at least a chain extender having a tertiary amine, and has a density of 1.0 g / cm3 or greater.

[0004] U.S. Patent No. 9484212 discloses a polished layer having a composition comprising a reaction product of a polyfunctional isocyanate and an amine-initiated polyol curing agent. The amine-initiated polyol curing agent contains at least one nitrogen atom / molecule and at least three hydroxyl groups / molecules. No single curing agent or polyol is used because the polyol contains amine functional groups capable of performing the curing function.

[0005] US Patent No. 10208154 discloses a two-component composition for manufacturing chemical mechanical polishing pads. The composition contains a liquid aromatic isocyanate component, a liquid polyol component having a polyether backbone and having 5-7 hydroxyl groups per molecule, and a curing agent. The curing agent is one or more aromatic polyamines or aromatic diamines.

[0006] U.S. Patent No. 9156127 discloses a polishing pad having a polishing layer. The polishing layer comprises a thermosetting polyurethane foam having generally spherical interconnected pores having an average pore diameter of 35 to 200 μm.

[0007] There is a need for chemical mechanical polishing layers or pads that have improved hardness, porosity, and removal rate performance without undesirably increasing the defect rate. This disclosure addresses this need by providing a composition for forming a polyurethane polishing layer using a hydroxyl-substituted aliphatic tertiary amine as a curing agent, thereby obtaining a high-porosity polishing pad with improved hardness and removal rate performance. [Summary of the Invention]

[0008] 1. According to the present invention, the organic solvent-free reaction mixture for forming a chemical mechanical polishing (CMP polishing) layer comprises: (i) a liquid aromatic isocyanate component comprising one or more aromatic diisocyanates or linear aromatic isocyanates-terminated urethane prepolymers having an unreacted isocyanate (NCO) concentration of 18 to 47 wt.% based on the total solid weight of the aromatic isocyanate component, (ii) a liquid polyol component, and (iii) one or more curing agents selected from the group consisting of amines having formulas (I) and (II); R1 and R2 are each independently C1-C6 alkyl, C1-C4 alkyl substituted with one or more C1-C4 alkyl groups or one or more halogens, -(CR5R6)pS-(CR5R6)q- or -(CR5R6)pO-(CR5R6)q-; R3 is a C1-C6 alkyl or a C1-C4 alkyl substituted with one or more C1-C4 alkyl groups; each R4 is independently H or -R1-OH; R5 and R6 are each independently H or C1-C6 alkyl; p and q are each independently integers from 1 to 5; and n is from 1 to 4, wherein the reaction mixture contains 55 to 75 wt.% hard segment material based on the total weight of the reaction mixture, and the total amount of the curing agent (I) and / or (II) is 9 to 26.8% based on the total weight of the reaction mixture. The CMP polished layer, by weight, has an unfilled Shore D (2 seconds) hardness of 57-77 or a filled Shore D (2 seconds) hardness of 18-50 and a density of 0.43 to 0.78 g / mL. The polished layer comprises a thermosetting polyurethane foam with generally spherical hollow pores, the pores being isolated or partially connected to form small, isolated clusters. The two-component reaction mixture contains no trace elements other than those formed by water or CO2-amine adducts.

[0009] 2. According to the present invention, the organic solvent-free reaction mixture for forming a chemical mechanical polishing (CMP polishing) layer as described in item 1 above, wherein the reaction mixture has a gelation time of 15 seconds to 3 minutes or preferably 15 seconds to 2 minutes at ambient temperature.

[0010] 3. According to a separate aspect of the invention, a chemical mechanical (CMP) polishing pad for polishing a substrate selected from at least one of magnetic substrates, optical substrates, and semiconductor substrates, the polishing pad comprising a polishing layer adapted to polish the substrate, the polishing layer comprising a polyurethane reaction product of a two-component reaction mixture free of organic solvents, the two-component reaction mixture comprising: (i) a liquid aromatic isocyanate component comprising one or more aromatic diisocyanates or linear aromatic isocyanate-terminated urethane prepolymers, preferably linear methylene diphenyl diisocyanate (MDI) prepolymers, having an unreacted isocyanate (NCO) concentration of 18 to 47 wt.%, or preferably 18 to 34 wt.%, based on the total solid weight of the aromatic isocyanate component; (ii) a liquid polyol component comprising one or more polymeric polyols, such as polytetramethylene glycol (PTMEG), polypropylene glycol (PPG), hexafunctional polyols, or mixtures thereof; and (iii) a product selected from those having formula (I). One or more curing agents of the group of amines (I) and (II); wherein R1, R2, R3, R4 and n are as defined above, wherein the reaction mixture contains 55 to 75 wt.%, or preferably 55 to 68 wt.%, of hard segment material based on the total weight of the reaction mixture, wherein the total amount of curing agents (I) and (II) is 9 to 41 wt.%, preferably 20 to 30 wt.%, based on the total weight of the reaction mixture, the CMP polished layer has an unfilled Shore D (2 seconds) hardness of 35-77, preferably 55 to 77 wt.%, or a filled Shore D (2 seconds) hardness of 10-50, preferably 18 to 50 wt.%, and a density of 0.43 to 0.78 g / mL, preferably greater than 0.50 to 0.78 g / mL, further wherein the CMP polished layer is free of trace elements other than those formed by water and CO2-amine adducts.

[0011] 4. The CMP polishing pad or reaction mixture of the present invention according to any one of items 1, 2 or 3 above, wherein the stoichiometric ratio of the sum of the total moles of amine (NH2) groups and the total moles of hydroxyl (OH) groups in the reaction mixture to the total moles of unreacted isocyanate (NCO) groups in the reaction mixture for making the CMP polishing layer is from 0.85:1.0 to 1.15:1.0, or preferably from 0.9:1.0 to 1.1:1.0.

[0012] 5. A CMP polishing pad according to any one of items 3 or 4 above, wherein the (i) liquid aromatic isocyanate component comprises one or more diisocyanate or isocyanate-terminated linear urethane prepolymer compounds selected from: methylene diphenyl diisocyanate (MDI); toluene diisocyanate (TDI); naphthalene diisocyanate (NDI); terephthalate diisocyanate (PPDI); or o-toluidine diisocyanate (TODI); mixtures thereof; any one of MDI, TDI, NDI, PPDA, TODI extended with one or more of the following extender compounds having a concentration of 84 to 100 wt.%, or preferably 90 to 100 wt.%. A linear isocyanate-terminated urethane prepolymer or mixture thereof with a hard segment material content of wt.%: ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 2-methyl-1,3-propanediol, 1,4-butanediol, neopentyl glycol, 1,5-pentanediol, 3-methyl-1,5-pentanediol, 1,6-hexanediol, diethylene glycol, dipropylene glycol, tripropylene glycol, and mixtures thereof, preferably a linear isocyanate-terminated urethane prepolymer of MDI (which is an MDI or MDI dimer extended with one or more extender compounds).

[0013] 6. The CMP polishing pad of the present invention according to any one of items 3, 4 or 5 above, wherein the one or more curing agents are selected from the group of amines having formula (II) as defined above, preferably n-system 2 or 3, and more preferably n-system 2.

[0014] 7. A chemical mechanical polishing pad of the present invention according to any one of items 1, 2, 3, 4, 5 or 6 above, the polishing pad comprising the CMP polishing layer and further comprising a sub-pad or backing layer, such as a polymer-impregnated nonwoven or polymer sheet, on the underside of the polishing layer, such that the polishing layer forms the top of the polishing pad.

[0015] 8. In another aspect, the present invention provides a method for manufacturing a chemical mechanical (CMP) polishing pad having a polishing layer adapted to a polishing substrate, the method comprising providing a two-component reaction mixture as described in any one of items 1, 2, 3, 4, 5 or 6 above, such as mixing the (i) liquid aromatic isocyanate component and the (ii) liquid polyol component in a static mixer or an impact mixer, and applying the reaction mixture as a component to an open mold surface (preferably having a positive morphology having a recessed pattern formed in the top surface of the CMP polishing pad), curing the reaction mixture at an ambient temperature to 130°C to form a molded polyurethane reaction product, for example, initially curing at an ambient temperature to 130°C for 1 to 30 minutes, or preferably for a period of 30 seconds to 5 minutes, removing the polyurethane reaction product from the mold, and then finally curing at a temperature of 60°C to 130°C for 1 minute to 16 hours, or preferably for a period of 30 minutes to 6 hours.

[0016] 9. The method of the present invention as described in item 8 above, wherein the formation of the polishing pad further comprises stacking a sub-pad layer, such as a polymer-impregnated nonwoven fabric or a porous or non-porous polymer sheet, onto the bottom side of the polishing layer, such that the polishing layer forms the top surface of the polishing pad.

[0017] 10. The method of the present invention according to any one of items 8 or 9 above, wherein the method directly forms the surface of the CMP polishing pad in the mold.

[0018] 11. The method of the present invention according to any one of items 8, 9 or 10 above, wherein applying the reaction mixture as a component comprises overspraying the mold, subsequently curing it to form a polyurethane reaction product, removing the polyurethane reaction product from the mold, and then stamping or cutting the periphery of the polyurethane reaction product to the desired diameter of the CMP polishing pad.

[0019] 12. In another aspect, the present invention provides a method for polishing a substrate, the method comprising: providing a substrate selected from at least one of a magnetic substrate, an optical substrate, and a semiconductor substrate; providing a chemical mechanical (CMP) polishing pad according to any one of items 1 to 7 above; creating dynamic contact between the polishing surface of the polishing layer of the CMP polishing pad and the substrate to polish the surface of the substrate; and adjusting the polishing surface of the polishing pad with an abrasive adjuster.

Implementation Method

[0021] Unless otherwise specified, temperature and pressure conditions refer to ambient temperature and standard pressure. All listed ranges include extreme values ​​and combinations thereof.

[0022] Unless otherwise specified, any term containing parentheses may instead refer to the entire term as if it did not contain parentheses, as well as terms without parentheses, and combinations of each alternative. Thus, the term "(poly)isocyanate" means isocyanate, polyisocyanate, or mixture thereof.

[0023] All ranges include end values ​​and can be combined. For example, the term "50 cPs to 3000 cPs, or 100 cPs or greater" would include each of 50 cPs to 100 cPs, 50 cPs to 3000 cPs, and 100 cPs to 3000 cPs.

[0024] For the purposes of this invention, unless otherwise specifically indicated, the reaction mixture is expressed in wt.%

[0025] As used herein, the term "ASTM" refers to the publications of ASTM International, West Conshohocken, PA.

[0026] As used herein, the term "average number of isocyanate groups" means the weighted average number of isocyanate groups in a mixture of aromatic isocyanate compounds. For example, a 50:50 wt.% mixture of MDI (2 NCO groups) and the isocyanurate of MDI (considered to have 3 NCO groups) has an average of 2.5 isocyanate groups.

[0027] As used herein, the term "gel time" means the result obtained by mixing a given reaction mixture for 30 s at approximately 65°C, for example, in a VM-2500 vortex laboratory mixer (StateMix Ltd., Winnipeg, Canada) (set at 1000 rpm), setting the timer to zero and turning it on, pouring the mixture into an aluminum cup, placing the cup in the hot pot (set at 65°C) of a gel timer (Gardco Hot Pot™ gel timer, Paul N. Gardner Company, Inc., Pompano Beach, FL), stirring the reaction mixture at 20 RPM using a wire mesh stirrer, and recording the gel time when the wire mesh stirrer stops moving in the sample.

[0028] As used herein, the term "hard segment" of a polyurethane reaction product or starting material of either the liquid polyol component or the liquid aromatic isocyanate component refers to a portion of a specified reaction mixture comprising any diol, glycol, bis(diol), tri(diol) having 6 or fewer carbon atoms, tetra(diol) having 15 or fewer carbon atoms, any diamine, triamine or polyamine, diisocyanate, triisocyanate, or reaction product thereof. Therefore, "hard segment" does not include polyethers or polydiols such as polyethylene glycol or polypropylene glycol, or polyoxyethylene having three or more ether groups.

[0029] As used herein, the term "trace elements other than those formed from water or CO2-amine adducts" means trace elements selected from hollow polymer materials such as polymer microspheres, liquid-filled hollow polymer materials such as fluid-filled polymer microspheres, and fillers such as boron nitride. Pores formed in CMP polished layers by gases or simply gas-forming foaming agents such as CO2-amine adducts are not considered trace elements.

[0030] As used herein, the term "polyisocyanate" means any isocyanate-containing molecule containing two or more isocyanate groups.

[0031] As used herein, the term "polyisocyanate prepolymer" means any molecule containing an isocyanate group, which is the product of the reaction of excess diisocyanate or polyisocyanate with a compound containing two or more active hydrogen groups (such as diamines, diols, triols and polyols).

[0032] As used herein, the term "polyurethane" refers to polymers derived from difunctional or polyfunctional isocyanates, such as polyether urea, polyisocyanurate, polyurethane, polyurea, polyurethane urea, copolymers thereof, and mixtures thereof.

[0033] As used herein, the term "curing agent" refers to low molecular weight (number average MW less than 500 g / mol) diols, diamines and polyhydroxy or polyamine functional compounds capable of capping polyurethane prepolymers and / or forming cross-linked network structures.

[0034] As used herein, the term "reaction mixture" includes any non-reactive additives, such as trace elements and any additives that reduce the hardness of polyurethane reaction products in CMP polishing pads according to ASTM D2240-15 (2015).

[0035] As used herein, the term "stoichiometry" for reaction mixture refers to the molar equivalent ratio of (free OH + free NH2 groups) to free NCO groups in the reaction mixture.

[0036] As used herein, the term "SG" or "specific gravity" refers to the weight / volume ratio of a rectangular object cut from a polishing pad or layer according to the invention.

[0037] As used herein, the term "Shore D hardness" refers to the 2-second hardness of a given CMP polishing pad as measured according to ASTM D2240-15 (2015), "Standard Test Method for Rubber Property—Durometer Hardness". Hardness was measured on a Hoto Instruments P2 Auto Durometer hardness tester equipped with an Asker D probe (Hoto Instruments, 3100 Dundee Rd, Northbrook, IL). For each hardness measurement, six samples were stacked and shuffled; and each pad was conditioned for five days at 23°C and 50% relative humidity before testing and improving the repeatability of the hardness test using the method outlined in ASTM D2240-15 (2015). In this invention, the Shore D hardness of the polyurethane reaction product of the polishing layer or pad includes the Shore D hardness of the reaction, which includes any additives used to increase the hardness. "Filled Shore D" is obtained on a material filled with gas (e.g., air), while "unfilled Shore D" is obtained on a material without pores formed by gas.

[0038] As used herein, the term "solid" means any material retained in the polyurethane reaction product of the present invention; therefore, solids include reactive and non-volatile liquids and additives that do not volatilize upon curing. Solids do not include water and volatile solvents.

[0039] As used herein, unless otherwise specified, the term “viscosity” means the viscosity of a given material in its pure form (100%) as measured at a given temperature using a rheometer set to an oscillating shear rate scan of 0.1–100 radians per second (in a 50 mm parallel plate geometry with a 100 µm gap).

[0040] As used herein, unless otherwise specified, the term "wt.% NCO" refers to the amount of unreacted or free isocyanate groups in a given isocyanate or isocyanate-terminated urethane prepolymer composition.

[0041] As used herein, the term "wt.%" represents weight percentage.

[0042] According to the present invention, the inventors of the present invention have found that CMP polishing pads with high porosity CMP polishing layers (with an unfilled Shore D (2 seconds) hardness of 57-77 or a filled Shore D (2 seconds) hardness of 18-50 and a density of 0.43 to 0.78 g / mL) are useful hard pads with attractive removal rates.

[0043] The CMP polishing pad of the present invention is formed from a two-component reaction mixture having a liquid aromatic diisocyanate component and a liquid polyol component further containing the liquid aromatic diisocyanate component. The liquid aromatic diisocyanate component comprises one or more liquid aromatic diisocyanate or linear aromatic isocyanate-terminated urethane prepolymers. Suitable linear urethane prepolymers may be methylene diphenyl isocyanate (MDI) diisocyanate prepolymers having an NCO content greater than 18 wt.%; examples of such linear aromatic isocyanate-terminated urethane prepolymers include a prepolymer formed from MDI and (di)ethylene glycol having an NCO content of 23.0 wt.% and an equivalent weight of 182 g / mol. Suitable reaction mixtures further comprise 5 to 30 wt.% (based on the total weight of the reaction mixture) of a hydroxyl-substituted aliphatic tertiary amine as a curing agent. The amine curing agent helps to impart good mechanical properties such as rapid reaction time, high tensile strength, and high tensile modulus.

[0044] The hard segments of the reaction mixture ensure good mechanical properties. The hard segments may be 55 to 75 wt.% of the reaction mixture and may constitute part of both the curing agent component and the aromatic isocyanate component.

[0045] As part of the hard segment of the reaction mixture, the diisocyanate is preferably methylene diphenyl diisocyanate (MDI), which is less toxic than toluene diisocyanate (TDI). The liquid aromatic isocyanate component may comprise a linear isocyanate-terminated urethane prepolymer formed from an extender or short-chain diols such as diols and bis(diols), or preferably monoethylene glycol (MEG), dipropylene glycol (DPG), and / or tripropylene glycol (TPG).

[0046] Preferably, the liquid aromatic diisocyanate component contains only the impurity level of aliphatic isocyanates.

[0047] The soft segment of the reaction mixture may comprise a polymeric polyol, such as (ii) a bifunctional polyether in the polyol component. Suitable soft polyols include PTMEG and PPG. Examples of available PTMEG-containing polyols are as follows: Terathane™ 2900, 2000, 1800, 1400, 1000, 650, and 250 from Invista, Wichita, KS; Polymeg™ 2900, 2000, 1000, and 650 from Lyondell Chemicals, Limerick, PA; and PolyTHF™ 650, 1000, and 2000 from BASF Corporation, Florham Park, NJ. Examples of available PPG-containing polyols include: Arcol™ PPG-425, 725, 1000, 1025, 2000, 2025, 3025, and 4000 from Covestro, Pittsburgh, PA; Voranol™, Voralux™, and Specflex™ product families from Dow, Midland, MI; and Multranol™, Ultracel™, Desmophen™, or Acclaim™ Polyol 12200, 8200, 6300, 4200, and 2200, each from Covestro (Leverkusen, DE).

[0048] The soft segments of the reaction mixture may also include one or more polyols having a polyether backbone and having 5 to 7 hydroxyl groups / molecules.

[0049] Suitable polyols having a polyether backbone and having 5 to 7 hydroxyl groups / molecule are available as follows: VORANOL™ 202 polyol (Dow) having 5 hydroxyl groups, a number average molecular weight of 590 and a hydroxyl value of 475 mg KOH / g; MULTRANOL™ 9185 polyol (Dow) having 6 hydroxyl groups, a number average molecular weight of 3,366 and a hydroxyl value of 100 mg KOH / g; or VORANOL™ 4053 polyol (Dow) having an average of 6.9 hydroxyl groups, a number average molecular weight of 12,420 and a hydroxyl value of 31 mg KOH / g.

[0050] Based on the total solid weight of the reaction mixture, the hydroxyl-substituted tertiary amine curing agent of the present invention may account for 5 to 30 wt.%, or more preferably 9 to 26.8 wt.%.

[0051] A suitable curing agent is selected from the group consisting of amines having formulas (I) and (II); wherein R1 and R2 are each independently C1-C6 alkyl, C1-C4 alkyl substituted with one or more C1-C4 alkyl or one or more halogens, -(CR4R5)pS-(CR4R5)q- or -(CR4R5)pO-(CR4R5)q-; each R3 is independently C1-C6 alkyl or C1-C4 alkyl substituted with one or more C1-C4 alkyl; R4 and R5 are each independently H or C1-C6 alkyl; p and q are each independently integers from 1 to 5; and n is from 1 to 4. However, the curing agent must be slow enough to allow mixing of the two-component reaction mixture. When combined with the aromatic isocyanate component and the polyol component, the curing agent must cause gelation (so that the reactive mixture no longer flows) for at least 15 seconds, or preferably at least 20 seconds.

[0052] To increase the reactivity of the polyol component with diisocyanate or polyisocyanate, a catalyst may be used. Suitable catalysts include any catalyst known to those skilled in the art, such as oleic acid, azelaic acid, dibutyltin dilaurate, tin octoate, bismuth octoate, 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU), tertiary amine catalysts such as DabcoTMTMR catalyst, triethyldiamine such as DABCOTM33 LV, and mixtures thereof. Amine catalysts can accelerate the foaming reaction.

[0053] The reaction mixture of the present invention is substantially free of added organic solvents.

[0054] The specific gravity of the obtained CMP polishing pad is from 0.43 to 0.78, preferably greater than 0.50 to 0.78. As the porosity increases, the bulk properties of the CMP polishing pad decrease, and the removal rate (RR) increases.

[0055] The CMP polishing pad or layer of the present invention comprises a porous material having a large number-average pore size (X50) (10 to 200 micrometers, or preferably 20 to 50 micrometers, as determined by scanning electron microscopy (SEM). The stoichiometry of the reaction mixture of the present invention (NH + OH): NCO is 0.85 : 1.0 to 1.15 : 1.0.

[0056] The chemical mechanical polishing layer or pad of the present invention comprises a polishing layer, which is a uniform dispersion of porous polyurethane. Uniformity is important for obtaining consistent polishing pad performance. Therefore, the reaction mixture of the present invention is selected such that the resulting pad morphology is stable and easily reproducible. For example, controlling additives such as antioxidants and impurities such as water is generally important for consistent manufacturing.

[0057] According to the present invention, a CMP polished layer can be produced by spraying a reaction mixture onto an open mold and allowing it to cure. Because the two-component reaction mixture of the present invention can be used as a fluid spray or deposition to produce a CMP polished layer, the reaction mixture of the present invention can react much faster than when such a layer is formed in a closed mold. A suitable gelation time for the reaction mixture at 65°C is 10 seconds or longer, or preferably 15 seconds to 2 minutes.

[0058] The liquid reaction mixture of the present invention may contain a very fast-curing component, wherein (i) the liquid aromatic isocyanate component and (ii) the liquid polyol component can gel in a gelation time as short as 15 seconds. The reaction must be slow enough that the reaction mixture can be mixed in a static or impact mixer after the two components are combined. A limiting factor for the gelation time is that the reaction mixture must react slowly enough not to clog the mixing head and to properly fill the mold when applied to the mold surface.

[0059] Preferably, the target or substrate in the method of the present invention is an open mold, wherein the pad produced will have a directly bonded groove pattern.

[0060] The CMP polishing layer of the present invention can be produced by combining a foaming agent (such as water or CO2 amine (urethane)) (e.g., CO2 alkanolamine foaming agent) with an impact-mixing or static-mixing reaction mixture. After impact or static mixing, the reactive mixture is atomized from a nozzle onto the target in an air-induced or airless spraying process. In this way, a polyurethane or polyurethane-urea CMP polishing layer with a variable density of 0.43 g / mL to 0.78 g / mL can be obtained in a controlled process, with good generalized spherical pore uniformity throughout the pad.

[0061] The rapid gelation time of the reaction mixture of the present invention means that the pores formed during spraying or deposition will remain in the cured CMP polished layer. Therefore, surfactants, such as nonionic surfactants (such as polyethoxylated siloxanes), are not required in the reaction mixture of the present invention to produce stable foam products.

[0062] The thermosetting polyurethane thus formed has generally spherical hollow cells, which are isolated or partially connected to form small, isolated clusters. In one embodiment, the thermosetting polyurethane has generally spherical, isolated hollow cells. In another embodiment, the thermosetting polyurethane has generally spherical hollow cells, which are partially connected to form small, isolated clusters. The size of the clusters varies from 2 to 10 cells per cluster, and more preferably 4 to 6 cells.

[0063] Furthermore, since the CMP polishing pad of the present invention is formed by spraying or foaming in the presence of a foaming agent to form foam, trace elements such as hollow microspheres are not required, and preferably trace elements are not present.

[0064] Porosity is introduced into the pad or polishing layer by spraying, and the resulting pad tensile modulus is a function of both the inherent polymer tensile modulus and porosity, and the increased porosity has the effect of reducing specific density. Therefore, for pads or polishing layers manufactured by two-component spraying, in order to provide an acceptable tensile modulus, the polymer matrix tensile modulus must be acceptablely high, preferably greater than 100 MPa and more preferably greater than 240 MPa.

[0065] The density of the polished layer or pad is measured according to ASTM D1622-08 (2008). Density is the same as specific gravity.

[0066] For the purposes of this invention, the removal rate refers to the removal rate expressed in Å / min.

[0067] The chemical mechanical polishing pad of the present invention may contain only a polishing layer of polyurethane reaction product or a polishing layer stacked on a sub-pad or sub-layer. The polishing layer of the polishing pad of the present invention, or in the case of a stacked pad, may be used in both porous and non-porous configurations, or in an unfilled configuration.

[0068] Preferably, the polishing layer in the chemical mechanical polishing pad of the present invention has an average thickness of 500 to 3750 micrometers (20 to 150 mils), or more preferably 750 to 3150 micrometers (30 to 125 mils), or even more preferably 1000 to 3000 micrometers (40 to 120 mils), or most preferably 1250 to 2500 micrometers (50 to 100 mils).

[0069] The chemical mechanical polishing pad of the present invention may further include at least one additional layer at the interface with the polishing layer. Preferably, the chemical mechanical polishing pad may further include a compressible sub-pad or base layer adhered to the polishing layer. The compressible base layer preferably improves the surface uniformity between the polishing layer and the substrate being polished.

[0070] The polishing layer of the chemical mechanical polishing pad of the present invention has a polishing surface adapted to form a polishing substrate. Preferably, the polishing surface has a macroscopic texture selected from at least one of apertures and grooves. The apertures may extend from the polishing surface or extend through the thickness of the polishing layer.

[0071] Preferably, the groove is arranged on the polishing surface such that at least one groove sweeps across the surface of the substrate being polished as the chemical mechanical polishing pad rotates during polishing.

[0072] Preferably, the polishing layer of the chemical mechanical polishing pad of the present invention has a polishing surface adapted to form a polishing substrate, wherein the polishing surface has a macro-texture, the macro-texture comprising a groove pattern formed therein and selected from curved grooves, linear grooves, apertures, and combinations thereof. Preferably, the groove pattern comprises a plurality of grooves. More preferably, the groove pattern is selected from groove designs, such as groove designs selected from the group consisting of: concentric grooves (which may be circular or spiral), curved grooves, mesh grooves (e.g., arranged as an XY grid on the pad surface), other regular designs (e.g., hexagonal, triangular), tire tread type patterns, irregular designs (e.g., fractal patterns), and combinations thereof. More preferably, the groove design is selected from the group consisting of: random grooves, concentric grooves, spiral grooves, mesh grooves, XY grid grooves, hexagonal grooves, triangular grooves, fractal grooves, and combinations thereof. Most preferably, the polishing surface has a spiral groove pattern formed therein. The groove profile is preferably selected from a rectangle with straight sidewalls, or the groove cross-section can be "V" shaped, "U" shaped, sawtooth shaped, and combinations thereof.

[0073] According to the method of manufacturing the polishing pad according to the invention, the chemical mechanical polishing pad may have macroscopic textures or groove patterns molded in its polishing surface to promote slurry flow and remove polishing debris from the pad-wafer interface. Such grooves may be formed in the polishing surface of the polishing pad by the shape of the mold surface, i.e., wherein the mold has a negative morphological form of macroscopic texture.

[0074] The chemical mechanical polishing pad of the present invention can be used to polish substrates selected from at least one of magnetic substrates, optical substrates and semiconductor substrates.

[0075] Preferably, the method for polishing a substrate according to the present invention includes: providing a substrate selected from at least one of a magnetic substrate, an optical substrate, and a semiconductor substrate (preferably a semiconductor substrate, such as a semiconductor wafer); providing a chemical mechanical polishing pad according to the present invention; creating a dynamic contact between the polishing surface of the polishing layer and the substrate to polish the surface of the substrate; and adjusting the polishing surface with an abrasive conditioner.

[0076] The adjustment polishing pad includes contacting the adjustment disk with the polishing surface when polishing is paused ("non-in-situ") or during intermittent interruptions in the CMP process ("in-situ"). The adjustment disk has a rough adjustment surface, which typically includes embedded diamond dots that cut minute grooves in the pad surface, grinding and scribing the pad material and renewing the polishing texture. Typically, the adjustment disk rotates in a fixed position relative to the axis of rotation of the polishing pad and sweeps across an annular adjustment area as the polishing pad rotates. Example: The invention will now be described in detail in the following non-limiting examples:

[0077] Unless otherwise stated, all temperatures are room temperature (21°C-23°C) and all pressures are atmospheric pressure (approximately 760 mm Hg or 101 kPa).

[0078] Although other raw materials are disclosed below, the following raw materials are used in this example: Curing agent: N-methyldiethanolamine (MDEA) (The Dow Chemical Company, Midland, MI) and Voranol™ 800, a tetrafunctional curing agent with a number average molecular weight MN of 281 (OH equivalent weight 70.1) (Dow Chemical Company, Midland, MI). MDI prepolymer: A linear isocyanate-terminated urethane prepolymer derived from MDI and small molecule dipropylene glycol (DPG) and tripropylene glycol (TPG), having an NCO content of approximately 23 wt.% and an equivalent weight of 182. 100 wt.% of this MDI prepolymer is considered as a hard segment. Niax™ L5345 surfactant: A nonionic organosilicone surfactant (Momentive, Columbus, OH). Bismuth neodecanoate (BiNDE): Organometallic carbamate catalyst (Sigma-Aldrich, St. Louis, Missouri). PTMEG####: Poly(THF) or polytetramethylene glycol, obtained by ring-opening polymerization of tetrahydrofuran (THF), and sold as PolyTHF™ polyol (BASF, Leverkusen, Germany). The numbers following PTMEG are average molecular weights as reported by the manufacturer. This polyol is commercially available from BASF (sold as PolyTHF™) and is obtained in three different grades of molecular weights of 650, 1000, or 2000 (PolyTHF 650, PolyTHF 1000, PolyTHF 2000).

[0079] The properties of CMP polishing pads were evaluated according to the following method: All tensile properties were measured according to ASTM D412-06a, "Standard Test Methods for Vulcanized Rubber and Thermoplastic Elastomers—Tension". Samples were cut into dog-bone C-size pieces. Unless otherwise specified, five test samples were measured, and the average of all test samples for each analyte was reported.

[0080] Hardness was measured on a Hoto Instruments P2 Auto Durometer hardness tester equipped with an Asker D probe (Hoto Instruments, 3100 Dundee Road, Northbrook, Illinois). For each hardness measurement, the pad samples were stacked and shuffled so that each sample was probed once until at least six data points were collected.

[0081] In all the following examples, an impact mixing and air spraying system with two tanks (isocyanate tank and polyol tank) is used to mix and spray the specified two-component reaction mixture onto an open mold to feed the mixing system. The two tanks are set at a given material flow rate, from which the relative amounts of the two components are easily determined. Flow from both tanks is started and stopped simultaneously.

[0082] Example 1: A two-component impact mixing and air spraying system was used to spray the reaction mixture into an open mold. 100 parts of MDI prepolymer were loaded into an isocyanate tank, while 73.66 parts of PolyTHF1000, 25.34 parts of Voranol™800, 0.99 parts of Niax™L5345 nonionic surfactant, and 0.01 parts of BiNDE catalyst were loaded into a polyol tank. The flow rate on the polyol side during spraying was 9.90 g / s, and the flow rate on the isocyanate (iso) side was 9.60 g / s. The air flow rate into the injection nozzle was set to a nominal rate of 90 L / min. The sprayed polyurethane formulation was guided into a mold with grooved features. The sprayed pad was cured in an oven set to 100°C for 10 min, then removed from the mold and further cured in the same oven at 100°C for 16 hours. The sprayed pad was cured in a 100°C oven for 10 min, then removed from the mold and cured in a 100°C oven for 16 h. The resulting polished layer had a hard segment weight fraction of 62.5 wt.% at 95% stoichiometry without added water, and produced a monolayer pad with a bulk density of 0.78 g / mL and exhibited a bulk tensile modulus of 255 MPa, a tensile strength of 15.9 MPa, and a 2-second Shore D hardness of 50.

[0083] Example 2: A two-component impact mixing and air spraying system was used to spray the reaction mixture into an open mold. 100 parts of MDI prepolymer were loaded into an isocyanate tank, while 74.02 parts of PolyTHF1000, 24.87 parts of Voranol™ 800, 0.99 parts of Niax™ L5345 nonionic surfactant, 0.01 parts of BiNDE catalyst, and 0.10 parts of DI water were loaded into a polyol tank. The flow rate on the polyol side during spraying was 9.85 g / s, and the flow rate on the isocyanate (iso) side was 9.65 g / s. The air flow rate into the injection nozzle was set to a nominal rate of 90 L / min. The sprayed polyurethane formulation was guided into a mold with grooved features. The sprayed pad was cured in a 100°C oven for 10 min, then removed from the mold and cured in a 100°C oven for 16 hours. The resulting polished layer has a hard segment weight fraction of 62.5 wt.% at 95% stoichiometry and produces a monolayer pad with a bulk density of 0.68 g / mL and exhibits a bulk tensile modulus of 179 MPa, a tensile strength of 11.7 MPa, and a 2-second Shore D hardness of 42.

[0084] Example 3: A two-component impact mixing and air spraying system was used to spray the reaction mixture into an open mold. 100 parts of MDI prepolymer were loaded into an isocyanate tank, while 74.58 parts of PolyTHF1000, 24.16 parts of Voranol™800, 1.00 parts of Niax™L5345 nonionic surfactant, 0.01 parts of BiNDE catalyst, and 0.25 parts of DI water were loaded into a polyol tank. The flow rate on the polyol side during spraying was 9.78 g / s, and the flow rate on the isocyanate (iso) side was 9.72 g / s. The air flow rate into the injection nozzle was set to a nominal rate of 90 L / min. The sprayed polyurethane formulation was guided into a mold with grooved features. The sprayed pad was cured in a 100°C oven for 10 min, then removed from the mold and cured in a 100°C oven for 16 hours. The resulting polished layer has a hard segment weight fraction of 62.5 wt.% at 95% stoichiometry and produces a monolayer pad with a bulk density of 0.58 g / mL and exhibits a bulk tensile modulus of 131 MPa, a tensile strength of 9.7 MPa, and a 2-second Shore D hardness of 34.

[0085] Example 4: A two-component impact mixing and air spraying system was used to spray the reaction mixture into an open mold. 100 parts of MDI prepolymer were loaded into an isocyanate tank, while 74.95 parts of PolyTHF1000, 23.69 parts of Voranol™800, 1.00 parts of Niax™L5345 nonionic surfactant, 0.01 parts of BiNDE catalyst, and 0.35 parts of DI water were loaded into a polyol tank. The flow rate on the polyol side during spraying was 9.77 g / s, and the flow rate on the isocyanate (iso) side was 9.73 g / s. The air flow rate into the injection nozzle was set to a nominal rate of 90 L / min. The sprayed polyurethane formulation was guided into a mold with grooved features. The sprayed pad was cured in a 100°C oven for 10 min, then removed from the mold and cured in a 100°C oven for 16 hours. The resulting polished layer has a hard segment weight fraction of 62.5 wt.% at 95% stoichiometry and produces a monolayer pad with a bulk density of 0.54 g / mL and exhibits a bulk tensile modulus of 124 MPa, a tensile strength of 8.2 MPa, and a 2-second Shore D hardness of 35.

[0086] Example 5: A two-component impact mixing and air spraying system was used to spray the reaction mixture into an open mold. 100 parts of MDI prepolymer were loaded into an isocyanate tank, while 73.33 parts of PolyTHF1000, 16.23 parts of Voranol™ 800, 9.19 parts of MDEA, 1.00 parts of Niax™ L5345 nonionic surfactant, and 0.25 parts of DI water were loaded into a polyol tank. The flow rate on the polyol side during spraying was 9.92 g / s, and the flow rate on the isocyanate (iso) side was 9.58 g / s. The air flow rate into the injection nozzle was set to a nominal rate of 90 L / min. The sprayed polyurethane formulation was guided into a mold with grooved features. The sprayed pad was cured in a 100°C oven for 10 min, then removed from the mold and cured in a 100°C oven for 16 hours. The resulting polished layer has a hard segment weight fraction of 62.5 wt.% at 105% stoichiometry and produces a monolayer pad with a bulk density of 0.43 g / mL and exhibits a bulk tensile modulus of 20.0 MPa, a tensile strength of 4.8 MPa, and a 2-second Shore D hardness of 18.

[0087] Example 6: A two-component impact mixing and air spraying system was used to spray the reaction mixture into an open mold. 100 parts of MDI prepolymer were loaded into an isocyanate tank, while 70.14 parts of PolyTHF650, 18.26 parts of Voranol™ 800, 10.35 parts of MDEA, 1.00 parts of Niax™ L5345 nonionic surfactant, and 0.25 parts of DI water were loaded into a polyol tank. The flow rate on the polyol side during spraying was 18.45 g / s, and the flow rate on the isocyanate (iso) side was 21.55 g / s. The air flow rate into the injection nozzle was set to a nominal rate of 110 L / min. The sprayed polyurethane formulation was guided into a mold with grooved features. The sprayed pad was cured in a 100°C oven for 10 min, then removed from the mold and cured in a 100°C oven for 16 hours. The resulting polished layer has a hard segment weight fraction of 67.5 wt.% at 105% stoichiometry and produces a monolayer pad with a bulk density of 0.52 g / mL and exhibits a bulk tensile modulus of 159 MPa, a tensile strength of 7.6 MPa, and a 2-second Shore D hardness of 40.

[0088] Example 7: A two-component impact mixing and air spraying system was used to spray the reaction mixture into an open mold. 100 parts of MDI prepolymer were loaded into an isocyanate tank, while 78.04 parts of PolyTHF650, 20.60 parts of Voranol™ 800, 0.01 parts of BiNDE catalyst, 1.00 parts of Niax™ L5345 nonionic surfactant, and 0.35 parts of DI water were loaded into a polyol tank. The flow rate on the polyol side during spraying was 9.32 g / s, and the flow rate on the isocyanate (iso) side was 10.18 g / s. The air flow rate into the injection nozzle was set to a nominal rate of 90 L / min. The sprayed polyurethane formulation was guided into a mold with grooved features. The sprayed pad was cured in a 100°C oven for 10 min, then removed from the mold and cured in a 100°C oven for 16 hours. The resulting polished layer has a hard segment weight fraction of 62.5 wt.% at 95% stoichiometry and produces a monolayer pad with a bulk density of 0.56 g / mL and exhibits a bulk tensile modulus of 172 MPa, a tensile strength of 9.65 MPa, and a 2-second Shore D hardness of 46.

[0089] Example 8: A two-component impact mixing and air spraying system was used to spray the reaction mixture into an open mold. 100 parts of MDI prepolymer were loaded into an isocyanate tank, while 71.89 parts of PolyTHF650, 26.75 parts of Voranol™ 800, 0.01 parts of BiNDE catalyst, 1.00 parts of Niax™ L5345 nonionic surfactant, and 0.35 parts of DI water were loaded into a polyol tank. The flow rate on the polyol side during spraying was 8.78 g / s, and the flow rate on the isocyanate (iso) side was 10.72 g / s. The air flow rate into the injection nozzle was set to a nominal rate of 90 L / min. The sprayed polyurethane formulation was guided into a mold with grooved features. The sprayed pad was cured in a 100°C oven for 10 min, then removed from the mold and cured in a 100°C oven for 16 hours. The resulting polished layer has a hard segment weight fraction of 67.5 wt.% at 95% stoichiometry and produces a monolayer pad with a bulk density of 0.52 g / mL and exhibits a bulk tensile modulus of 248 MPa, a tensile strength of 12.4 MPa, and a 2-second Shore D hardness of 45.

[0090] Example 9: A two-component impact mixing and air spraying system was used to spray the reaction mixture into an open mold. 100 parts of MDI prepolymer were loaded into the isocyanate tank, while 30.31 parts of PolyTHF650, 44.10 parts of Voranol™ 220-260, 24.23 parts of Voranol™ 800, 0.01 parts of BiNDE catalyst, 1.00 parts of Niax™ L5345 nonionic surfactant, and 0.35 parts of DI water were loaded into the polyol tank. The flow rate on the polyol side during spraying was 17.39 g / s, and the flow rate on the isocyanate (iso) side was 22.61 g / s. The air injection nozzle was set to a nominal rate of 110 L / min. The sprayed polyurethane formulation was guided into a mold with grooved features. The sprayed pad was cured in a 100°C oven for 10 min, then removed from the mold and cured in a 100°C oven for 16 h. The resulting polished layer had a hard segment weight fraction of 67.5 wt.% at 95% stoichiometry and produced a monolayer pad with a bulk density of 0.47 g / mL and exhibited a bulk tensile modulus of 248 MPa, a tensile strength of 15.9 MPa, and a 2-second Shore D hardness of 45.

[0091] Comparative Example 1: The reaction mixture was sprayed into an open mold using a two-component impact mixing and air spraying system. 100 parts of MDI prepolymer were loaded into the isocyanate tank, while 69.83 parts of PolyTHF1000, 4.07 parts of Voranol™ 800, 24.85 parts of Ethacure® 300, 1.00 parts of Niax™ L5345 nonionic surfactant, and 0.25 parts of DI water were loaded into the polyol tank. The flow rate on the polyol side during spraying was 10.42 g / s, and the flow rate on the isocyanate (iso) side was 9.08 g / s. The air injection nozzle was set to a nominal rate of 90 L / min. The sprayed polyurethane formulation was guided into a mold with grooved features. The sprayed pad was cured in a 100°C oven for 10 min, then removed from the mold and cured in a 100°C oven for 16 hours. The resulting polished layer has a hard segment weight fraction of 62.5 wt.% at 95% stoichiometry and produces a monolayer pad with a bulk density of 0.53 g / mL and exhibits a bulk tensile modulus of 82.7 MPa, a tensile strength of 9.4 MPa, and a 2-second Shore D hardness of 36.

[0092] Comparative Example 2: The reaction mixture was sprayed into an open mold using a two-component impact mixing and air spraying system. 100 parts of MDI prepolymer were loaded into the isocyanate tank, while 67.7 parts of PolyTHF1000, 31.3 parts of Ethacure®300, and 1.00 parts of NiaxTML5345 nonionic surfactant were loaded into the polyol tank. The flow rate on the polyol side during spraying was 10.74 g / s, and the flow rate on the isocyanate (iso) side was 8.76 g / s. The air flow rate into the injection nozzle was set to a nominal rate of 90 L / min. The sprayed polyurethane formulation was guided into a mold with grooved features. The sprayed pad was cured in a 100°C oven for 10 min, then removed from the mold and cured in a 100°C oven for 16 hours. The resulting polished layer has a hard segment weight fraction of 62.5 wt.% at 95% stoichiometry and produces a monolayer pad with a bulk density of 0.84 g / mL and exhibits a bulk tensile modulus of 296 MPa, a tensile strength of 24.6 MPa, and a 2-second Shore D hardness of 57.

[0093] Polishing experiments were performed using 300 mm wafers on an Applied Reflexion polisher (Applied Materials, Santa Clara, CA) or using 200 mm lenses on a Mirra polisher (Applied Materials, Santa Clara, CA), with carrier pressures of 0.0102, 0.014, 0.017, 0.021, and 0.024 MPa (1.5, 2.0, 2.5, 3.0, and / or 3.5 psi), a slurry flow rate of 300 mL / min (200 mL / min on the Mirra polisher), and CSL9044C slurry (Fujifilm), a stage rotation speed of 93 rpm, and a carrier rotation speed of 87 rpm. A Saesol AF38 (Saesol) regulator was used to adjust and texturize the polishing pad. The polishing pads were individually abraded for 30 min each using a regulator and DI water at a downforce of 31.2 N. During polishing, the pads were further 100% in-situ conditioned at 19 scans / min with a downforce of 31.2 N from 51 to 373 mm (2.0 to 14.7 inches) from the center of the polishing pad. Copper wafers (Novellus) were polished at each downforce test. For performance comparison, IC1000TM and VisionPadTM6000 (DuPont, CMPT) were used as controls.

[0094] The removal rate was determined by measuring the film thickness before and after polishing using a KLA-Tencor RS-200 thin film measurement system (KLA Tencor, Milpitas, CA) with a 65-point diameter scan. The removal rate (in angstroms per minute) was calculated by measuring the thickness change at each point within a specified polishing time.

[0095] The polishing results are summarized in Table 1-5 below.

[0096] Table 1 shows that Examples 1-4 of the present invention have comparable to, or even superior, copper removal rates when compared to the commercially available VisionPad™ 6000 (300 mm wafer) used on an Applied Reflexion polishing machine with 300 mm wafers. [Table 1] pad Cu RR (Å / min) 1.5 psi Cu RR (Å / min) 2 psi Cu RR (Å / min) 2.5 psi Cu RR (Å / min) 3 psi %RR Improvement 3 psi VisionPad TM 6000 5400 6900 7900 8700 - Example 1 4900 - 8700 10600 twenty two Example 2 5200 - 9200 11000 26 Example 3 5200 - 9300 10700 twenty three Example 4 5000 7200 9200 10400 20

[0097] Table 2 shows that Example 5 of the present invention exhibits a superior copper removal rate compared to the commercially available VisionPad™ 6000 (300 mm wafer) used on an Applied Reflexion polisher. [Table 2] pad Cu RR (Å / min) 1.5 psi Cu RR (Å / min) 2 psi Cu RR (Å / min) 2.5 psi Cu RR (Å / min) 3 psi %RR Improvement 3 psi VisionPad TM 6000 5000 6500 7500 8400 - Example 5 5600 7400 8500 9500 13

[0098] Table 3 shows that Examples 6-9 of the present invention have comparable to, or even superior, copper removal rates when compared to the commercially available IC1000TM (300 mm wafer) used on an Applied Reflexion polishing machine with 300 mm wafers. [Table 3] pad Cu RR (Å / min) 1.5 psi Cu RR (Å / min) 2.5 psi Cu RR (Å / min) 3.5 psi %RR Improvement At 3.5 psi IC1000 TM 5400 9100 10100 - Example 6 6000 9600 10800 7 Example 7 6000 10000 11300 12 Example 8 5200 10100 11800 17 Example 9 5100 9800 11500 14

[0099] Table 4 shows that, compared to the commercial product IC1000TM, Example 3 of the present invention has a comparable to superior copper removal rate, while compared to Example 1 using a 300 mm wafer on an Applied Reflexion polishing machine or IC1000TM (300 mm wafer), it is worse. [Table 4] pad Cu RR (Å / min) 1.5 psi Cu RR (Å / min) 2 psi Cu RR (Å / min) 2.5 psi Cu RR (Å / min) 3 psi %RR Improvement 3 psi IC1000 TM 5100 7200 8600 10000 - Example 3 5100 7600 9500 10700 7% Comparison Example 1 4100 5700 5700 8100 -19%

[0100] Table 5 shows that, compared to the commercial product IC1000TM, Example 1 of the present invention has a comparable to superior copper removal rate, while compared to Example 1 or IC1000TM using a 200 mm wafer on a Mirra polishing machine, Comparative Example 2 is worse. [Table 5] pad Cu RR (Å / min) 1.5 psi Cu RR (Å / min) 2.5 psi Cu RR (Å / min) 3.5 psi IC1000 TM 3500 8100 11300 Example 1 4000 7800 11400 Comparison Example 2 3300 7700 10600 [Simplified Explanation of the Diagram]

[0020] None [Biomaterial Storage]

[0102] None

Claims

1. A chemical mechanical (CMP) polishing pad for polishing a substrate selected from at least one of magnetic substrates, optical substrates, and semiconductor substrates, the polishing pad comprising a polishing layer adapted to polish the substrate, the polishing layer comprising a thermosetting polyurethane foam having generally spherical hollow pores, the pores being isolated or partially connected to form small isolated clusters, the polyurethane foam being the product of a two-component reaction mixture containing the following organic solvent-free components: (i) a liquid aromatic isocyanate component comprising one or more aromatic diisocyanates or linear aromatic isocyanates-terminated urethane prepolymers having an unreacted isocyanate (NCO) concentration of 18 to 47 wt.% based on the total solid weight of the aromatic isocyanate component, (ii) a liquid polyol component, and (iii) one or more curing agents selected from the group consisting of amines having formulas (I) and (II); R1 and R2 are each independently C1-C6 alkyl, C1-C4 alkyl substituted with one or more C1-C4 alkyl groups or one or more halogens, -(CR5R6)pS-(CR5R6)q- or -(CR5R6)pO-(CR5R6)q-; R3 is a C1-C6 alkyl or a C1-C4 alkyl substituted with one or more C1-C4 alkyl groups; each R4 is independently H or -R1-OH; R5 and R6 are each independently H or C1-C6 alkyl; p and q are each independently integers from 1 to 5; and n is from 1 to 4, wherein the reaction mixture contains 55 to 75 wt.% hard segment material based on the total weight of the reaction mixture, and the total amount of the curing agent (I) and / or (II) is 9 to 26.8% based on the total weight of the reaction mixture. The CMP polished layer has an unfilled Shore D (2 seconds) hardness of 57-77 or a filled Shore D (2 seconds) hardness of 18-50 and a density of 0.43 to 0.78 g / mL.

2. The CMP polishing pad as described in claim 1, wherein, This liquid aromatic isocyanate component comprises a linear aromatic isocyanate-terminated urethane prepolymer.

3. The CMP polishing pad as described in claim 2, wherein, The one or more curing agents are selected from the group of amines having formula (II).

4. The CMP polishing pad as described in claim 3, wherein, n-series 2.

5. The CMP polishing pad as described in claim 4, wherein, The CMP polished layer has a density of 0.50 to 0.78 g / mL.

6. The CMP polishing pad as described in claim 1, wherein, The polished layer comprises thermosetting polyurethane foam with generally spherical hollow pores, which are isolated or partially connected to form small, isolated clusters.

7. The CMP polishing pad as described in claim 6, wherein, The one or more curing agents are selected from the group of amines having formula (II).

8. The CMP polishing pad as described in claim 7, wherein, n-series 2.

9. The CMP polishing pad as described in claim 6, wherein, The polished layer comprises thermosetting polyurethane foam with generally spherical hollow pores, which are isolated or partially connected to form small, isolated clusters.

10. The CMP polishing pad as described in claim 9, wherein, The one or more curing agents are selected from the group of amines having formula (II).