Polyurethanes, polishing articles and polishing systems made therefrom, and methods of use thereof

Abstract

Polyurethanes and polishing articles prepared therefrom are described, the polyurethane comprising the reaction product of a reactive mixture comprising a polyol, a diol chain extender, a diisocyanate, a monohydric alcohol, and a polyfunctional amine. The molar ratio of isocyanate groups to hydroxyl groups in the reactive mixture is 0.98 or more. Such polyurethanes can remain stable even when exposed to elevated reactive extrusion temperatures for extended periods of time.

Description

Background Art

[0001] Polyurethane synthesis and film production are described, for example, in U.S. Patent Publication No. 2020 / 0277517 and U.S. Patent No. 10,590,303. The use of polyurethane films in polishing articles is described, for example, in U.S. Patents Nos. 10,071,461 and 10,252,396. Summary of the invention

[0002] In one aspect, the present specification relates to a polyurethane comprising a reaction product of a reactive mixture comprising a polyol, a diol chain extender, a diisocyanate, a monool, and a polyfunctional amine, wherein the molar ratio of isocyanate groups to hydroxyl groups in the reactive mixture is 0.98 or greater. BRIEF DESCRIPTION OF THE DRAWINGS

[0003] Figure 1 is a schematic cross-sectional view of a portion of a polishing layer according to some embodiments described herein.

[0004] Figure 2 is a schematic cross-sectional view of a polishing pad according to some embodiments described herein.

[0005] Figure 3 Schematic diagrams of examples of polishing systems utilizing polishing pads and methods according to some embodiments described herein are illustrated. DETAILED DESCRIPTION

[0006] Polyurethanes are general-purpose resins that are typically synthesized from a mixture of polyols and polyisocyanates. Polyols are organic compounds having at least two alcohol functional groups, and polyisocyanates are organic compounds having at least two isocyanate functional groups. In addition to these core components, other compounds may be added during synthesis, including but not limited to chain extenders, chain terminators, crosslinking agents, catalysts, etc. Both thermoplastic polyurethanes and thermosetting polyurethanes may be synthesized, and because a large number of compounds may be used in their synthesis, a wide range of material properties can be achieved. Polyurethanes are commonly used in and as protective coatings and films, at least due to their general toughness, wear resistance, and chemical resistance.

[0007] One area where polyurethane films may be particularly useful is as an abrasive for various polishing applications, such as chemical mechanical planarization (CMP) polishing applications. In a typical CMP process, the surface of a substrate (e.g., a semiconductor wafer) contacts the surface of a polishing pad. This contact is typically performed in the presence of a working liquid or slurry. The substrate is moved relative to the pad under a specific force or pressure, thereby removing material from the substrate surface in a controlled manner. Polishing pads typically have multiple layers, including a polishing layer (i.e., a layer of the pad designed to contact the substrate) and a subpad. The design of the polishing layer is important for polishing performance. Some polishing layers may include a working surface (i.e., a surface intended to contact the substrate being polished) having a polishing feature (e.g., a protrusion and / or a hole) having a specific shape or design that is conducive to the polishing process. The height of the protrusion and / or the depth of the hole (if included) are important parameters that affect the performance of the polishing pad. For example, for protrusions, it may be advantageous that the height of the highest protrusion is uniform or substantially uniform, thereby producing a flat surface at the tip of the protrusion. This allows the substrate surface to be uniformly contacted on the group of protrusions. In addition, the total thickness of the polishing layer may be important for the performance of the polishing pad. Generally, it may be advantageous for the polishing layer to have a uniform thickness to allow the working surface of the polishing layer to be flat. Thickness variations may translate into non-planarity of the working surface of the polishing layer and affect polishing performance: the substrate may only contact thicker areas of the polishing layer and not thinner areas elsewhere on the polishing layer. In addition, any non-uniform thickness may also result in non-uniform polishing pressure, which may adversely affect the polishing results. The uniformity of the thickness of the polishing layer and / or the size of the polishing features, which are critical to the polishing process, may result in demanding tolerance requirements, because the polishing layer in film form may have a thickness of less than 1 mm in some cases, and the corresponding polishing features may have a size (e.g., height or depth) between 20 microns and 100 microns.

[0008] In addition to these size requirements, the working fluid (e.g., polishing solution or slurry) may be corrosive (acidic, alkaline, and / or highly oxidizing), so the polishing layer may be constructed or selected to provide good chemical resistance. Similarly, in certain applications, it may be important that the polishing layer lasts long enough to meet the polishing life requirements of a given polishing process, so the polishing layer may be constructed or selected to provide good wear resistance. Other potentially advantageous characteristics include the ability to be produced at low cost, easily repeatable, and / or a high-volume manufacturing process.

[0009] One method of producing a polishing feature on the working surface of the polishing layer is by using an embossing process. In this method, the polishing layer can be prepared from a thermoplastic material, which is melt-processed (e.g., via an extruder) and cast onto an embossing roller and includes a negative image of the desired polishing layer feature. In some embodiments, if the feature is on a scale or has a size of about 500 microns or less, the process can be considered or referred to as a micro-replication process. The thermoplastic material is then cooled on the embossing roller to cause solidification, and the thermoplastic film with the embossed feature is subsequently removed from the roller. With regard to melt processing, the thermoplastic material can be synthesized, granulated, and then processed into a film in the subsequent process. However, higher efficiency can be achieved by preparing the thermoplastic material in situ by reactive extrusion in an extruder. The produced polyurethane can then be formed into a film. In either case, a stable fluid flow is required during the casting / embossing process to ensure uniform film thickness and uniform feature size. For example, the stable fluid flow during melt processing can be related to the stable melt viscosity of the thermoplastic material at the melt processing temperature. Polyurethanes that can be used as polishing layers for CMP pads may require high temperatures (e.g., temperatures between 180° C. and 250° C.) to form a melt. Changes in viscosity or other properties of the urethane melt within this temperature range can result in unacceptable coating defects. In addition, low viscosity of the polyurethane melt within this temperature range can result in low pressure during the manufacturing process (e.g., casting / imprinting microreplication process), which in turn can result in poor replication accuracy. Therefore, in some embodiments, a urethane material with a high melt viscosity between 180° C. and 250° C. can be used.

[0010] In addition to the above characteristics, the zeta potential of the polyurethane of the present specification may be important in some embodiments. For example, the zeta potential of a polyurethane used as a polishing layer of a CMP pad may affect the polishing behavior exhibited by the pad. Therefore, the ability to change, select or affect the zeta potential of a polyurethane may result in improved polishing performance. The zeta potential may be changed by blending compounds (typically lower molecular weight compounds) with various functional groups into the polyurethane. However, these compounds may be prone to migration and / or diffusion within the polyurethane and may not remain uniformly dispersed throughout the polyurethane. For example, during the use of the polishing layer of a CMP pad, the polyurethane may contact an aqueous and / or non-aqueous polishing solution that may be able to extract components from the polyurethane, particularly at the surface area of ​​the polyurethane polishing layer. These components may then diffuse into the polishing solution (i.e., removed from the polyurethane polishing layer), thereby rendering them ineffective as zeta potential modifiers.

[0011] The polyurethanes described herein may include multifunctional amines that can react into a polyurethane backbone while changing the zeta potential of the polyurethane. Typically, these compounds increase the zeta potential of the polyurethane and can provide a polyurethane with a positive zeta potential. Since the multifunctional amines are typically uniformly dispersed throughout the polyurethane and permanently included in the backbone due to covalent bonding, the zeta potential of the polyurethane changes in a more stable manner and can maintain a more consistent value during the intended use. When the polyurethane wears during use (e.g., during a CMP polishing process), new polyurethanes will be exposed with a zeta potential substantially equal to the now corroded surface. This behavior can be distinguished from the behavior of materials that cannot react into the polyurethane itself during synthesis and / or are only blended into the reacted polyurethane, because these materials can diffuse and phase separate within the polyurethane, bloom on the polyurethane surface, and / or be extracted from the polyurethane during use.

[0012] The unreacted end groups in the urethane copolymer may cause instability and inconsistency of the polyurethane, especially at elevated temperatures, such as during extrusion. The end groups can be controlled by excess hydroxyl groups or amine groups relative to the isocyanate groups. The reaction of amines with isocyanates is usually faster than the reaction of hydroxyls with isocyanates. Therefore, in the early stages of the reaction, amines may be disproportionately consumed to form urea groups. However, in this system, the thermal stability of urea groups is lower than that of urethane groups, especially when urea groups are sterically hindered. At elevated temperatures (e.g., close to the extrusion temperature), urea groups are reduced to isocyanates and amines. These isocyanates then react with unreacted hydroxyl groups less reversibly. At elevated temperatures, these unreacted amine end groups accumulate and the overall properties and composition of the polyurethane may change unpredictably. A series of exemplary reactions are shown below:

[0013]

[0014] Including monohydric alcohol in the reactive mixture can minimize this problem and produce more stable polyurethane. The end group of the chain is not an excessive hydroxyl group or amine group, but a reaction product of a monohydric alcohol and a diisocyanate. In this case, in order to avoid excessive hydroxyl groups, the isocyanate index (molar ratio of isocyanate groups to hydroxyl groups) should be close to 1.0 or greater. In some embodiments, the isocyanate index should be 0.99 or greater. In some embodiments, the isocyanate index should be 0.98 or greater. In some embodiments, the isocyanate index should be 0.95 or greater. Here, although the urea group can be reduced to isocyanate groups and amine groups at an elevated temperature, there is still no large amount of unreacted hydroxyl end groups. Therefore, isocyanate is forced to react with amine again to reform the urea group, and the stability of the polyurethane can also be improved even at the reaction extrusion temperature.

[0015] In some embodiments, the present description is directed to a polyurethane comprising a reaction product of a reactive mixture comprising a polyol, a diol chain extender, a diisocyanate, and a polyfunctional amine according to at least one of Formula I and Formula II, the polyfunctional amine having the following structure:

[0016]

[0017] In some embodiments, X is an integer from 0 to 10, including the end values, R1 is a straight or branched aliphatic group, a cyclic aliphatic group, an aromatic group, or a compound containing an aromatic group having 2 to 20 carbon atoms, R2 is a straight or branched alkyl group having 1 to 20 carbon atoms, and R2' is hydrogen or a straight or branched alkyl group having 1 to 20 carbon atoms. In some embodiments, X can be an integer from 0 to 5, 0 to 3, 1 to 10, 1 to 5, or 1 to 3, including the end values. In some embodiments, R1 is a straight or branched aliphatic group, a cyclic aliphatic group, an aromatic group, or a compound containing an aromatic group having 2 to 16 carbon atoms, 2 to 12 carbon atoms, or 2 to 8 carbon atoms. In some embodiments, R2 is a straight or branched chain alkyl group having 1 to 16 carbon atoms, 1 to 12 carbon atoms, 1 to 10 carbon atoms, or 1 to 8 carbon atoms, and / or R2' is hydrogen or a straight or branched chain alkyl group having 1 to 16 carbon atoms, 1 to 12 carbon atoms, 1 to 10 carbon atoms, or 1 to 8 carbon atoms. In some embodiments, R2 is a straight or branched chain alkyl group having 1 to 10 carbon atoms, and R2' is hydrogen. Mixtures of Formula I and Formula II can be used.

[0018] The multifunctional amines of formula I and formula II each have two significant features. One feature is that each multifunctional amine contains two less hindered secondary amines (excluding R2-substituted side chain amines with triazine), i.e., the two carbon atoms in the α position of the nitrogen of the less hindered secondary amine are not tertiary carbon atoms, or equivalently, the two carbon atoms in the α position of the nitrogen contain at least one bond to a hydrogen atom. In this case, less hindered means relatively less steric hindrance than the amine in the 2,2,6,6-tetramethylpiperidine ring. The less hindered secondary amine functional groups are then able to react with other components of the reactive mixture. The second feature is that each multifunctional amine contains at least two hindered secondary amines, i.e., the two carbon atoms in the α position of the nitrogen of the hindered secondary amine are tertiary carbon atoms, or equivalently, the two carbon atoms in the α position of the nitrogen do not include a bond connected to a hydrogen atom. Due to their greater steric hindrance, hindered secondary amines are generally unable to react with other components of the reactive mixture or the reaction rate is significantly reduced, so that they do not play an important role in forming the polyurethane of the present specification. The number of hindered secondary amines in the multifunctional amines of Formula I and Formula II depends on the value of X. Therefore, the number of hindered amines N in the multifunctional amines of Formula I and Formula II can vary according to the following formula: N = 2X + 2. In some embodiments, the number of hindered secondary amines in the multifunctional amines of Formula I and Formula II can be 2 to 22, 2 to 16, 2 to 12, or 2 to 8.

[0019] During the polymerization of the polyurethane, the presence of two less hindered secondary amines of the multifunctional amines of formula I and formula II enables the compound to react with the diisocyanate groups of the reaction mixture (covalent bonds to form urea bonds) and be incorporated into the polyurethane of the present specification, i.e., the multifunctional amines of formula I and formula II become part of the polyurethane backbone. This feature prevents the migration and / or diffusion of the multifunctional amines, and the compound can generally be uniformly dispersed throughout the polyurethane. This feature also prevents the multifunctional amines from being extracted from the polyurethane during, for example, use as a polishing layer of a CMP pad. During use as a polishing layer of a CMP pad, the polyurethane may contact an aqueous and / or non-aqueous polishing solution, which may be able to extract components from the polyurethane, such as lower molecular weight compounds, particularly at the surface area of ​​the polyurethane polishing layer. These components may then diffuse into the polishing solution, i.e., be removed from the polyurethane polishing layer, rendering them ineffective. Since they are covalently bonded to the polyurethane backbone, the multifunctional amines cannot be extracted / removed from the polyurethane of the present specification. This behavior is in contrast to that of polyfunctional amines which are not capable of reacting to the polyurethane and / or being simply blended into the polyurethane during synthesis.

[0020] When polyfunctional amines react to the polyurethanes of this specification, they may need to be included in the calculation of the stoichiometry of the reactive mixture for forming the polyurethane. Typically, the stoichiometry of the reactive mixture is calculated by the ratio of isocyanate functional groups (related to the diisocyanate of the reactive mixture) to hydroxyl functional groups (related to the polyols and diol chain extenders of the reactive mixture). In the case where polyfunctional amines are included in the reactive mixture, the stoichiometry can be calculated by the ratio of isocyanate functional groups (related to the diisocyanate of the reactive mixture) to hydroxyl functional groups and less hindered secondary amine functional groups (related to the polyols, diol chain extenders and polyfunctional amines of the reactive mixture). In some embodiments, the molar ratio of isocyanate groups to hydroxyl groups and less hindered secondary amine groups in the reactive mixture is between 0.96 and 1.08, between 0.97 and 1.06, between 0.98 and 1.04, or between 0.99 and 1.04. In some embodiments, the amount of polyfunctional amine in the reactive mixture is greater than 2 weight percent, greater than 4 weight percent, greater than 6 weight percent, or even greater than 8 weight percent, based on the total weight of the reactive mixture. In some embodiments, the amount of polyfunctional amine in the reactive mixture is greater than 2 weight percent and less than 15 weight percent, greater than 3 weight percent and less than 15 weight percent, greater than 4 weight percent and less than 15 weight percent, greater than 4 weight percent and less than 12.5 weight percent, or greater than 6 weight percent and less than 10 weight percent, based on the total weight of the reactive mixture.

[0021] The polyfunctional amines contain hindered secondary amines, and the hindered secondary amines provide an important property; they enable the zeta potential of the polyurethanes of the present specification to be changed. Typically, the polyurethane will have a negative zeta potential throughout the pH range of 2 to 10. The inclusion of polyfunctional amines with their hindered secondary amines into the polyurethane enables the formation of polyurethanes having a higher zeta potential or even a positive zeta potential at acidic pH. In addition, the zeta potential of the polyurethanes of the present specification can be changed or "adjusted" according to the amount of polyfunctional amine added to the reactive mixture (i.e., covalently bonded to the polyurethane). Generally speaking, the greater the amount of polyfunctional amine incorporated into the polyurethane, the more positive the zeta potential of the polyurethane. The structure of the sterically hindered amine can affect the pH range in which the zeta potential is positive. Compared with amines with lower alkalinity, sterically hindered amines with more alkaline characteristics can adopt positive zeta potentials at higher pH values. Although not bound by theory, the pH range in which the zeta potential becomes positive is generally related to the pKb of the hindered amine. In some embodiments, the pKb of the hindered amine is less than or equal to 6, less than or equal to 5.5, less than or equal to 5.0, or less than or equal to 4.5, and / or greater than or equal to 2.0, greater than or equal to 2.5, or greater than or equal to 3.0. Generally speaking, 2,2,6,6-tetramethylpiperidinyl groups with secondary amines are more basic and more preferred than 1,2,2,6,6-pentamethylpiperidinyl groups and similar structures with tertiary amines. The zeta potential of a polyurethane can affect its performance characteristics in certain applications, for example, when the polyurethane is used as a polishing layer in a CMP application. During CMP applications, the polishing layer will typically be in contact with a polishing solution, which is a slurry, i.e., contains abrasive particles. The abrasive particles themselves may have a negative zeta potential. Although not wishing to be bound by theory, it is believed that a polyurethane with a negative zeta potential may repel slurry particles that also have a negative zeta potential. This may adversely affect polishing performance by, for example, reducing the removal rate or increasing the non-uniformity of the removal rate. However, if the polishing pad has a positive zeta potential, this may attract slurry particles having a negative zeta potential to the polishing layer surface and may provide one or more benefits, such as an enhanced removal rate.

[0022] The polyfunctional amine can be prepared by the reaction of N,N'-(bis-2,2,6,6-tetramethylpiperidin-4-yl)hexane-1,6-diamine with at least one of (i) a dihalogenated, alkyl-modified 1,3,5-triazine-2-amine, (ii) a diacid, and (iii) a diacyl halide. The dihalogenated, alkyl-modified 1,3,5-triazine-2-amine can include at least one of chlorine, bromine, and fluorine substitution. Examples of suitable dihalogenated, alkyl-modified 1,3,5-triazine-2-amines include 4,6-dichloro-N-octyl-1,3,5-triazine-2-amine, 4,6-dichloro-N,N-dimethyl-1,3,5-triazine-2-amine, 4,6-dichloro-N,N-dipropyl-1,3,5-triazine-2-amine, 4,6-dichloro-N,N-dihexyl-1,3,5-triazine-2-amine, 4,6-dichloro-N-(1,1,3,3-tetramethylbutyl)-1,3,5-triazine-2-amine, etc. Combinations of dihalogenated, alkyl-modified 1,3,5-triazine-2-amines may be used. An exemplary multifunctional amine that can be prepared from the reaction of N,N′-(bis-2,2,6,6-tetramethylpiperidin-4-yl)hexane-1,6-diamine and a dihalogenated, alkyl-modified 1,3,5-triazine-2-amine is poly[[6-[(1,1,3,3-tetramethylbutyl)amino]-1,3,5-triazine-2,4-diyl][(2,2,6,6-tetramethyl-4-piperidinyl)imino]-1,6-hexanediyl[(2,2,6,6-tetramethyl-4-piperidinyl)imino]], which is available from BASF, Florham Park, New Jersey, under the trade designation CHIMASSORB 944. Examples of suitable diacids include terephthalic acid (e.g., 1,4-terephthalic acid), 1,4-naphthalene dicarboxylic acid, isophthalic acid, phthalic acid, 2,6-naphthalene dicarboxylic acid, diphenyl dicarboxylic acid, succinic acid, adipic acid, azelaic acid, maleic acid, glutaric acid, suberic acid, sebacic acid, dodecanedioic acid, 1,4-cyclohexane dicarboxylic acid, etc. Combinations of diacids can be used. Examples of suitable diacyl halides include bromine, chlorine or fluorine substituted diacids, including bromine, chlorine or fluorine substituted diacids of the present specification, such as 1,4-terephthaloyl dichloride, 1,4-terephthaloyl difluoride, isophthaloyl difluoride, 1,6-adipic dichloride, 1,4-malonyl dibromide, etc. Combinations of diacyl halides can be used.

[0023] Reactive mixture comprises polyol.The polyol of reactive mixture can comprise any suitable number of hydroxyl groups, and comprises at least two hydroxyl groups.For example, polyol can comprise at least six hydroxyl groups, at least four hydroxyl groups, at least three hydroxyl groups or at least two hydroxyl groups.In some embodiments, polyol has the number average molecular weight of at least 400 daltons.In some embodiments, polyol has between 400Da and 10,000Da, between 400Da and 5,000Da, between 400Da and 2,000Da, between 450Da and 10,000Da, between 450Da and 5,000Da, between 450Da and 2,000Da, between 500Da and 10,000Da, between 500Da and 5,000Da or between 500Da and 2,000Da.The type of polyol has no particular restrictions.Can use the combination of different types of polyols. In some embodiments, the polyol may be at least one of a polyester polyol, a polyether polyol, a polycarbonate polyol, and a hydroxyl-terminated butadiene.

[0024] In some embodiments, the polyol can be a polyester polyol. The polyester polyol can be the product of a condensation reaction such as a polycondensation reaction. In embodiments where the polyester polyol is prepared according to a condensation reaction, the reaction can be carried out between one or more carboxylic acids and one or more diols. Examples of suitable carboxylic acids include carboxylic acids according to formula III, which have the following structure:

[0025]

[0026] In formula III, R3 can be selected from substituted or unsubstituted C1-C40 alkylene, C2-C40 alkylene, C2-C40 alkenylene, C4-C20 arylene, C4-C20 cycloalkylene and C4-C20 aralkylene. Specific examples of suitable carboxylic acids include, but are not limited to, glycolic acid (2-hydroxyacetic acid), lactic acid (2-hydroxypropionic acid), succinic acid (butyric acid), 3-hydroxybutyric acid, 3-hydroxyvaleric acid, terephthalic acid (benzene-1,4-dicarboxylic acid), naphthalene dicarboxylic acid, 4-hydroxybenzoic acid, 6-hydroxynaphthalene-2-carboxylic acid, oxalic acid, malic acid (malonic acid), adipic acid, syrup (pimelic acid), acetic acid, suberic acid, azelaic acid, sebacic acid (sebacic acid), gum acid (glutaric acid), dodecanedioic acid (dedecandioic acid) acid), tridecanedioic acid, hexadecanedioic acid, maleic acid ((2Z)-but-2-enedioic acid), fumaric acid ((2E)-but-2-enedioic acid), glutaconedioic acid (pent-2-enedioic acid), 2-decanedioic acid, traumatic acid ((2E)-dodec-2-enedioic acid), muconic acid ((2E,4E)-hexa-2,4-dienedioic acid), glutinic acid, citraconic acid ((2Z)-2-methylbut-2-enedioic acid), mesaconic acid ((2E)-2-methyl-2-butenedioic acid), itaconic acid (2-methylenesuccinic acid), malic acid (2-hydroxysuccinic acid), aspartic acid (2-aminosuccinic acid), glutamic acid (2-aminoglutaric acid), tartonic acid acid), tartaric acid (2,3-dihydroxysuccinic acid), diaminopimelic acid ((2R,6S)-2,6-diaminopimelic acid), saccharic acid ((2S,3S,4S,5R)-2,3,4,5-tetrahydroxyhexanedioic acid), methoxyoxalic acid, oxaloacetic acid (oxosuccinic acid), acetone dicarboxylic acid (3-oxoglutaric acid), arabinonic acid (arbinaric acid), phthalic acid (benzene-1,2-dicarboxylic acid), isophthalic acid, biphenyl dicarboxylic acid, 2,6-naphthalene dicarboxylic acid or a mixture thereof.

[0027] Examples of suitable diols for the condensation reaction include diols according to Formula IV having the following structure:

[0028]

[0029] In Formula IV, R4 can be selected from substituted or unsubstituted C1-C40 alkylene, C2-C40 alkenylene, C4-C20 arylene, C1-C40 acylene, C4-C20 cycloalkylene, C4-C20 aralkylene and C1-C40 alkyleneoxy, and R5 and R5' are independently selected from -H, substituted or unsubstituted C1-C40 alkyl, C2-C40 alkenyl, C4-C20 aryl, C1-C20 acyl, C4-C20 cycloalkyl, C4-C20 aralkylene and C1-C40 alkoxy. Suitable polyols include, but are not limited to, ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,3-butylene glycol, 1,4-butylene glycol, 1,5-pentanediol, 1,6-hexanediol, 2,2-dimethyl-1,3-propanediol, 1,4-cyclohexanedimethanol, decamethylene glycol, dodecamethylene glycol, glycerol, trimethylolpropane, and mixtures thereof.

[0030] In some embodiments, the polyol is prepared by ring-opening polymerization, such as the ring-opening polymerization of ε-caprolactone.

[0031] Suitable polyester polyols include, but are not limited to, polybutylene adipate, polyethylene adipate, poly(diethylene adipate), polyhexylene adipate, poly(neopentyl adipate), poly(butylene adipate-co-phthalate), polycaprolactone, or copolymers thereof. Combinations of different polyester polyols may be used.

[0032] In some embodiments, the polyol of the reactive mixture may be a polyether polyol, including but not limited to polyoxyalkylene polyols, polyoxycycloalkylene polyols, and oxyalkylene adducts thereof. In some embodiments, the polyether polyol may be at least one of polyoxyethylene polyols (e.g., polyethylene glycol), polyoxypropylene polyols (e.g., polypropylene glycol), polyoxytetramethylene polyols (e.g., polyoxytetramethylene glycol), copolymers thereof, and mixtures thereof, and may have a hydroxyl functionality of 2 to 6, particularly 2 to 4.

[0033] Polyether polyols are well known and can be prepared by reacting compounds containing hydroxyl groups with, for example, ethylene oxide, propylene oxide, tetramethylene oxide in the presence of a base catalyst to produce polyoxyethylene polyols, polyoxypropylene polyols, and polyoxytetramethylene, respectively. Copolymers containing at least two of ethylene oxide, propylene oxide, and tetramethylene oxide can also be used. A variety of compounds containing hydroxyl groups can be used to initiate the reaction, including, for example, ethylene glycol, propylene glycol, butylene glycol, glycerol, 2,2-dimethylolpropane, pentaerythritol, and the like. Examples of commercially available polyether polyols include Arcol polyether polyols available under the trade designations PPG 425, PPG 725, LHT 112, and LHT 240 (from Arco Chemical Co., Newtown Square, PA); polyethylene glycols, such as those available under the trade designation Carbowax Sentry (Dow Chemical Co., Midland, MI); PLURACOL E 1450 polyethylene glycol (BASF Corp., Parsippany, NJ); and TERATHANE poly(tetramethylene oxide) polyol (EI DuPont de Nemours; Wilmington, DE).

[0034] In some embodiments, the polyol of the reactive mixture can be a polycarbonate polyol. Polycarbonate polyols can be obtained from the reaction of aliphatic diols such as 1,4-butanediol and 1,6-hexanediol with phosgene, diaryl carbonates such as diphenyl carbonate or with cyclic carbonates such as ethylene carbonate or propylene carbonate. Aliphatic diols can be any one or combination of the diols discussed about formula IV. Examples of commercially available polycarbonate polyols include ARAMACO PERFORMANCE MATERIALS CONVERGE POLYO 212-10, 212-20, CPX-2001-112, CPX-2502-56a and HMA-2 purchased from Aramaco Performance Materials, LLC, Houston, TX, of Houston, Texas.

[0035] In some embodiments, the polyol of reactive mixture can be or include hydroxyl-terminated butadiene.Hydroxy-terminated butadiene can be hydroxyl-terminated polybutadiene, and polybutadiene can be homopolymer or copolymer.The example of commercially available hydroxyl-terminated butadiene includes " LIQUIFLEX H " from Petroflex, Wilmington, DE, Delaware and both from POLY-BD-45HTLO and KrasolLBH P 2000 of Cray Valley USA, LLC, Exton, PA, both from Exton, Pennsylvania.In some embodiments, the polyol of reactive mixture can be or include saturated hydroxyl-terminated polybutadiene.The example of commercially available saturated hydroxyl-terminated polybutadiene is Krasol HLBH P 2000 from Cray Valley USA, LLC, Exton, Pennsylvania.

[0036] By the weight of reactive mixture, polyol can be present in the reaction mixture in an amount between 30 wt % and 80 wt %.In some embodiments, by the weight of reactive mixture, the amount of polyol present in reactive mixture is greater than or equal to 30 wt %, 35 wt %, 40 wt %, 45 wt %, 50 wt %, and / or is less than or equal to 80 wt %, 75 wt %, 70 wt %, 65 wt % or 60 wt %.By the gross weight of the polyester polyol in reactive mixture, polyester polyol can comprise the polyester diol of at least 70 wt %.In some embodiments, by the gross weight of the polyester polyol in reactive mixture, polyester polyol comprises the polyester diol of at least 70 wt %, at least 75 wt %, at least 80 wt %, at least 85 wt %, at least 90 wt %, at least 95 wt %, at least 97 wt %, at least 99 wt % or 100 wt %.

[0037] The reactive mixture includes a diol chain extender. The diol chain extender can be described by Formula IV, wherein R4 is selected from substituted or unsubstituted C1-C16 alkylene, C2-C16 alkenylene, C4-C20 arylene, C1-C16 acylene, C4-C16 cycloalkylene, C4-C16 aralkylene and C1-C16 alkyleneoxy, and R5 and R5' are independently selected from -H, substituted or unsubstituted C1-C16 alkyl, C2-C16 alkenyl, C4-C16 aryl, C1-C16 acyl, C4-C16 cycloalkyl, C4-C16 aralkylene and C1-C16 alkoxy, and R5 and R5' are prohibited from being hydroxyl and being substituted by hydroxyl. Suitable diols include, but are not limited to, ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,3-butylene glycol, 1,4-butylene glycol, 1,5-pentanediol, 1,6-hexanediol, 2,2-dimethyl-1,3-propylene glycol, 1,4-cyclohexanedimethanol, decamethylene glycol, diethylene glycol, hydroquinone bis(2-hydroxyethyl) ether, and dodecamethylene glycol. In some embodiments, the diol chain extender includes at least one of a C1-C16 aliphatic diol and a C4-C16 alicyclic diol. In some embodiments, the C1-C16 aliphatic diol includes a C1-C16 alkylene, and optionally, the C1-C16 alkylene is a straight-chain C2-C16 alkylene having a hydroxyl substitution at two terminal carbon atoms. The diol chain extender may be in the range of about 1% by weight to about 15% by weight of the reaction mixture or about 2% by weight to about 15% by weight of the reactive mixture. In some embodiments, the amount of diol chain extender present in the reactive mixture is greater than or equal to 1 wt%, 2 wt%, 3 wt%, 4 wt%, 5 wt%, 6 wt%, and / or less than or equal to 15 wt%, 14 wt%, 13 wt%, 12 wt%, or less than 11 wt%, based on the weight of the reactive mixture. In some embodiments, the diol chain extender has a molecular weight of less than 400 Daltons, less than 350 Daltons, or less than 300 Daltons. For example, the molecular weight of the diol chain extender may be in the range of 30 Daltons to less than 400 Daltons, 30 Daltons to 350 Daltons, 30 Daltons to 300 Daltons, or 50 Daltons to less than 400 Daltons. In some embodiments, the molecular weight of the diol chain extender may be a number average molecular weight.

[0038] The reactive mixture comprises a diisocyanate. The diisocyanate is not particularly limited and may be a monomer, an oligomer or a polymer. Examples of suitable diisocyanates include diisocyanates according to Formula V having the following structure:

[0039] O=C=N-R6-N=C=O

[0040] Formula V.

[0041] In Formula V, R6 is selected from substituted or unsubstituted C1-C 40Alkylene, C2-C 40 Alkenylene, C4-C 20 Arylene, C4-C 20 Arylene-C1-C 40 Alkylene-C4-C 20 Arylene, C4-C 20 Cycloalkylene and C4-C 20 In some embodiments, the diisocyanate is selected from dicyclohexylmethane-4,4'-diisocyanate, isophorone diisocyanate, hexamethylene diisocyanate, 1,4-phenylene diisocyanate, 1,3-phenylene diisocyanate, m-xylene diisocyanate, toluene-2,4-diisocyanate, toluene-2,6-diisocyanate, poly(hexamethylene diisocyanate), 1,4-cyclohexylene diisocyanate, 4-chloro-6-methyl-1,3-phenylene diisocyanate, diphenylmethane 4,4'-diisocyanate, diphenylmethane 2,4-diisocyanate, 1,4-diisocyanatobutylene , 1,8-diisocyanato octane, 2,5-toluene diisocyanate, methylene bis(o-chlorophenyl diisocyanate), (4,4'-diisocyanato-3,3',5,5'-tetraethyl) diphenylmethane, 4,4'-diisocyanato-3,3'-dimethoxybiphenyl (o-dianisidine diisocyanate), 5-chloro-2,4-toluene diisocyanate, 1-chloromethyl-2,4-diisocyanatobenzene, tetramethyl-m-xylene diisocyanate, 1,12-diisocyanatododecane, 2-methyl-1,5-diisocyanatopentane, 2,2,4-trimethylhexyl diisocyanate or a mixture thereof.

[0042] In some embodiments, diisocyanate can be the diisocyanate of chain extension, i.e. the reaction product of diisocyanate and dihydroxy-terminated oligomer or polymer (e.g. dihydroxy-terminated linear oligomer or polymer). During the reaction, an excess of diisocyanate is used to ensure that the reaction product of at least 80 wt %, 90 wt %, 95 wt %, 97 wt %, 98 wt %, 99 wt % or 99.5 wt % is also diisocyanate. Dihydroxy-terminated oligomer or polymer is not particularly limited, and can include, for example, dihydroxy-terminated linear polyester and dihydroxy-terminated linear polyether. Polyester polyol (particularly the polyester diol discussed before about the polyester polyol of this specification) can be used to form the diisocyanate of chain extension. In some embodiments, the polyester polyol of the diisocyanate of chain extension can include the reaction product of one or more C2-C12 diols and one or more C2-C12 diacids. In some embodiments, the diisocyanate includes diphenylmethane diisocyanate, the reaction product of diphenylmethane diisocyanate and a hydroxyl-terminated linear oligomer or polymer, toluene diisocyanate, the reaction product of toluene diisocyanate and a hydroxyl-terminated linear oligomer or polymer, and combinations thereof. An exemplary chain-extended diisocyanate is ethylene-co-butylene adipate polyester terminated with 4,4'-diphenylmethane diisocyanate (MDI), which is available from Huntsman Corporation, The Woodlands, TX, under the trade name "RUBINATE 1234".

[0043] In some embodiments, the amount of diisocyanate in the reaction mixture is 10% to 60% by weight, based on the weight of the reactive mixture. In some embodiments, the amount of diisocyanate in the reaction mixture is greater than or equal to 10%, 15%, 20%, 25%, and / or less than or equal to 60%, 55%, 50%, or 45% by weight, based on the weight of the reactive mixture.

[0044] The reactive mixture may also include a catalyst to facilitate the reaction between the polyisocyanate and the polyol component. Available catalysts in the polymerization reaction of polyurethane include catalysts based on aluminum, bismuth, tin, vanadium, zinc, mercury and zirconium, amine catalysts and mixtures thereof. Preferred catalysts include tin-based catalysts, such as dibutyltin compounds. In some embodiments, the catalyst includes but is not limited to dibutyltin diacetate, dibutyltin dilaurate, dibutyltin diacetylacetonate, dibutyltin dithiol, dibutyltin dioctoate, dibutyltin dimaleate, dibutyltin acetone acetone and dibutyltin oxide. The suitable amount of the catalyst may be 0.001% to 1%, 0.001% to 0.5% or 0.001% to 0.25%. In some embodiments, the amount of catalyst in the reactive mixture may be greater than or equal to 0.001 wt%, 0.002 wt%, 0.005 wt%, 0.01 wt%, 0.02 wt%, 0.05 wt%, 0.07 wt%, 0.1 wt%, and / or less than or equal to 1.0 wt%, 0.7 wt%, 0.5 wt%, or 0.3 wt%, based on the weight of the reactive mixture.

[0045] In some embodiments, the reaction mixture may contain a polyol having at least three hydroxyl groups and / or a polyisocyanate having at least three corresponding isocyanate groups. In this case, the polyol and / or polyisocyanate may serve as a branching agent. The amount of the polyol and / or polyisocyanate must be limited to maintain the general thermoplastic properties of the resulting polyurethane. However, components of this nature can be used to increase molecular weight or change the viscosity characteristics of the polyurethane.

[0046] In some embodiments, the reactive mixture comprises a monohydric alcohol. In some embodiments, the monohydric alcohol can be a fatty alcohol. Fatty alcohols are typically straight-chain primary alcohols with hydroxyl end groups. Fatty alcohols include 1-decanol, dodecanol, stearyl alcohol, oleyl alcohol, and lauryl alcohol. Fatty alcohols can be C6-C12 fatty alcohols, although fatty alcohols with any chain length between C4-C26 can be used in certain embodiments. In some embodiments, the reactive mixture comprises a monohydric alcohol with a relatively high boiling point to prevent the monohydric alcohol from evaporating before the completion of the urethane polymerization. The monohydric alcohol may have a boiling point higher than the reaction temperature during the urethane polymerization. In some embodiments, the monohydric alcohol includes a branched aliphatic group. In some embodiments, the monohydric alcohol has a chain length between C8-C24, and in some embodiments, the monohydric alcohol has a chain length between C10-C20. Branched monoalcohols include 2-ethyl-1-hexanol, 2-butyl-1-octanol, 2-pentyl-1-nonanol, 2-hexyl-1-decanol, 2-octyl-1-dodecanol, 2-decyl-1-tetradecanol, isooctyl alcohol, isodecanol, isododecanol, 2,4,4-trimethyl-1-pentanol and 3,5,5-trimethyl-1-hexanol. In some embodiments, the monoalcohol can be a secondary alcohol. Secondary monoalcohols include 2-octanol, 3-octanol, 4-octanol, 2-nonanol, 4-nonanol, 5-nonanol, 2-decanol and 2-dodecanol. In some embodiments, the monoalcohol may contain an ether group. The ether-containing monohydric alcohols include diethylene glycol monobutyl ether, diethylene glycol monoethyl ether, diethylene glycol monomethyl ether, ethylene glycol monobutyl ether, di(propylene glycol) butyl ether, di(propylene glycol) propyl ether, di(propylene glycol) methyl ether, propylene glycol butyl ether and propylene glycol propyl ether.

[0047] Other additives may be included in the reactive mixtures and polyurethanes of the present disclosure, including, but not limited to, antioxidants, light / UV stabilizers, dyes, colorants, filler particles, abrasive particles, reinforcing particles or fibers, viscosity modifiers, etc. Additives that are insoluble in the reactive mixture (e.g., filler particles, abrasive particles, and reinforcing particles or fibers) are not included in the calculation of the weight percentages of the components of the reactive mixture, i.e., they are not included in the total weight of the reactive mixture used as the basis for the weight percentages of each component of the reactive mixture.

[0048] The polyurethane of the present specification may have a stable viscosity under the processing conditions (e.g., temperature, pressure, and time) used to make articles therefrom. The viscosity of the polyurethane at 200° C. may be less than 1,000,000 cP, less than 3,000,000 cP, less than 5,000,000 cP, less than 10,000,000 cP, or less than 15,000,000 cP, and / or greater than 100,000 cP, greater than 75,000 cP, greater than 50,000 cP, greater than 40,000 cP, or greater than 35,000 cP.

[0049] The polyurethanes of this specification can be used in a variety of applications and are particularly suitable for the formation of thin films. Due to their unique chemical resistance, wear resistance, zeta potential and moldability, the polyurethanes of this specification are particularly useful as polishing layers in, for example, polishing pads. In one embodiment, this specification provides a polishing pad comprising a polishing layer having a working surface and a second surface opposite to the working surface, wherein the polishing layer comprises the polyurethane described in any one of the embodiments of this specification. Optionally, the polishing layer may comprise at least 90 wt %, at least 95 wt %, at least 99 wt % or 100 wt % of the polyurethane.

[0050] In many polishing applications (e.g., CMP applications), it is generally desirable to make the working surface of the polishing layer of the polishing pad include a topography, i.e., non-flat. The topography can be formed by grinding a substantially flat polishing layer surface with the grinding surface of a pad conditioner. The abrasive particles of the pad conditioner typically remove areas of the polishing layer surface in a random manner, and then produce a topography in the polishing layer surface. Another method of producing a topography in the working surface of the polishing layer of the polishing pad is by a micro-replication process, such as an embossing process. Such a process provides a working surface of the polishing layer, which is precisely designed and constructed to have a plurality of reproducible topographical features, including convex bodies and / or holes. The convex bodies and holes are designed to have sizes ranging from millimeters to microns, with exemplary achievable tolerances as low as 1 micron or less. Due to the precisely constructed convex topography of the polishing layer, the polishing pad of the present specification can be used without a pad dressing process, thereby eliminating the need for an abrasive pad conditioner and a corresponding dressing process. In addition, the precisely constructed pore topography ensures uniform pore size and distribution on the working surface of the polishing pad, which can lead to improved polishing performance and lower polishing solution usage. Due to its stable flow characteristics, the polyurethane of the present specification is particularly suitable for making precisely constructed protrusions and pore topography in the working surface of the polishing layer, and can meet the stringent tolerances of the design. Polishing pads and polishing layers that can use the polyurethane of the present specification are disclosed in, for example, U.S. Patent No. 10,252,396, which is incorporated herein by reference in its entirety.

[0051] Figure 1A schematic cross-sectional view of a portion of a polishing layer 10 according to some embodiments of the present specification is shown. The polishing layer 10 having a thickness X includes a working surface 12 and a second surface 13 opposite to the working surface 12. The working surface 12 is a precisely constructed surface having a precisely constructed topography. The working surface includes at least one of a plurality of precisely formed holes, precisely formed protrusions, and combinations thereof. The working surface 12 includes a plurality of precisely formed holes 16 having a depth Dp, a sidewall 16a, and a base 16b, and a plurality of precisely formed protrusions 18 having a height Ha, a sidewall 18a, and a top 18b (the top has a width Wd). The width of the precisely formed protrusions and the protrusion bases may be the same as the width Wd of their tops. The bottom surface region 14 is located in the region between the precisely formed holes 16 and the precisely formed protrusions 18 and may be considered as part of the working surface. The intersection of the precisely formed protrusion sidewall 18a with the surface of the bottom surface region 14 adjacent thereto defines the location of the bottom of the protrusion and defines a set of precisely formed protrusion bases 18c. The intersection of the precisely formed hole sidewall 16a and the surface of the adjacent bottom surface region 14 is considered to be the top of the hole and defines a set of precisely formed hole openings 16c having a width Wp. Since the base of the precisely formed protrusion and the opening of the adjacent precisely formed hole are determined by the adjacent bottom surface region, the base of the protrusion is substantially coplanar with respect to at least one adjacent hole opening. In some embodiments, a plurality of protrusion bases are substantially coplanar with respect to at least one adjacent hole opening. The plurality of protrusion bases may include at least about 10%, at least about 30%, at least about 50%, at least about 70%, at least about 80%, at least about 90%, at least about 95%, at least about 97%, at least about 99%, or even at least about 100% of the total protrusion base of the polishing layer. The bottom surface region provides different separation areas between precisely formed features, including separation between adjacent precisely formed protrusions and precisely formed holes, separation between adjacent precisely formed holes, and / or separation between adjacent precisely formed protrusions. In some embodiments, the working surface includes a bottom surface region and at least one of a plurality of precisely formed holes and a plurality of precisely formed projections.

[0052] Although there may be slight curvature and / or thickness variations consistent with the manufacturing process, the bottom surface region 14 can be substantially planar and have a substantially uniform thickness Y. Because the thickness Y of the bottom surface region must be greater than the depth of the plurality of precisely formed holes, the bottom surface region can have a greater thickness than other abrasive articles known in the art that may have only protrusions. In some embodiments of the present specification, when both precisely formed protrusions and precisely formed holes are present in the polishing layer, including the bottom surface region allows the surface density of the plurality of precisely formed protrusions to be designed independently of the surface density of the plurality of precisely formed holes, thereby providing greater design flexibility. This is in contrast to conventional pads, which may include a series of intersecting grooves formed in a generally flat pad surface. The intersecting grooves result in a textured working surface, and the grooves (areas where material is removed from the surface) define an upper area of ​​the working surface (areas where material is not removed from the surface), i.e., an area that will contact the substrate being ground or polished. In this known method, the size, layout and number of the grooves define the size, layout and number of the upper area of ​​the working surface, i.e., the areal density of the upper area of ​​the working surface depends on the areal density of the grooves. The grooves can also extend the length of the pad, thereby allowing the polishing solution to flow out of the grooves as compared to the holes that can contain the polishing solution. In particular, for demanding applications (e.g., CMP), the inclusion of precisely shaped holes that can hold and retain the polishing solution close to the working surface can provide enhanced polishing solution delivery.

[0053] Polishing layer 10 may include at least one macrochannel. Figure 1 A macro-channel 19 having a width Wm, a depth Dm, and a base 19a is shown. A sub-bottom surface region having a thickness Z is defined by the macro-channel base 19a. The sub-bottom surface region defined by the base of the macro-channel will be considered as part of the bottom surface region 14 previously described. In some embodiments, one or more secondary pores (not shown) may be included in at least a portion of the base of at least one macro-channel. One or more secondary pores have a secondary pore opening (not shown) that is substantially coplanar with the base 19a of the macro-channel 19. In some embodiments, the base of at least one macro-channel is substantially free of secondary pores. In some embodiments, the polishing layer includes a plurality of independent or interconnected macro-channels.

[0054] The shape of the precisely formed hole 16 is not specifically limited and includes, but is not limited to, a cylinder, a hemisphere, a cube, a rectangular prism, a triangular prism, a hexagonal prism, a triangular pyramid, a 4-sided, 5-sided and 6-sided pyramid, a truncated pyramid, a cone, a truncated cone, and the like. The lowest point of the precisely formed hole 16 relative to the hole opening is considered to be the bottom of the hole. The shapes of all precisely formed holes 16 may be the same, or a combination may be used. In some embodiments, at least about 10%, at least about 30%, at least about 50%, at least about 70%, at least about 90%, at least about 95%, at least about 97%, at least about 99% or even at least about 100% of the precisely formed holes are designed to have the same shape and size. Due to the precise manufacturing method used to make the precisely formed holes, the tolerances are generally small. For a plurality of precisely formed holes designed to have the same hole size, the hole size is uniform. In some embodiments, the standard deviation of at least one distance dimension corresponds to the dimension of the plurality of precisely formed holes; for example, the height, width, length, and diameter of the hole openings is less than about 20%, less than about 15%, less than about 10%, less than about 8%, less than about 6%, less than about 4%, less than about 3%, less than about 2%, or even less than about 1% of the average value of the distance dimension. The standard deviation can be measured by known statistical techniques. The standard deviation can be calculated from a sample size of at least 5 holes, or even at least 10 holes, or at least 20 holes. The sample size can be no greater than 200 holes, no greater than 100 holes, or even no greater than 50 holes. The sample can be randomly selected from a single area on the polishing layer or from multiple areas of the polishing layer.

[0055] The longest dimension of the precisely formed hole opening 16c (e.g., the diameter when the shape of the precisely formed hole 16 is cylindrical) can be less than about 10 mm, less than about 5 mm, less than about 1 mm, less than about 500 microns, less than about 200 microns, less than about 100 microns, less than about 90 microns, less than about 80 microns, less than about 70 microns, or even less than about 60 microns. The longest dimension of the precisely formed hole opening 16c can be greater than about 1 micron, greater than about 5 microns, greater than about 10 microns, greater than about 15 microns, or even greater than about 20 microns. The cross-sectional area of ​​the precisely formed hole 16 (e.g., the circle when the shape of the precisely formed hole 16 is cylindrical) can be uniform throughout the depth of the hole; or the cross-sectional area can decrease if the precisely formed hole sidewall 16a tapers inwardly from the opening to the base; or the cross-sectional area can increase if the precisely formed hole sidewall 16a tapers outwardly. Depending on the design, the precision-formed hole openings 16c may all have approximately the same longest dimension or the longest dimension may vary between precision-formed hole openings 16c or between different groups of precision-formed hole openings 16c. The width Wp of the precision-formed hole openings may be equal to the value given above for the longest dimension.

[0056] The depth Dp of the plurality of precisely shaped holes is not particularly limited. In some embodiments, the depth of the plurality of precisely shaped holes is less than the thickness of the bottom surface region adjacent to each precisely shaped hole, i.e., the precisely shaped holes are not through holes that pass through the entire thickness of the bottom surface region 14. This enables the holes to capture and retain fluids close to the working surface. Although the depth of the plurality of precisely shaped holes may be limited as indicated above, this does not prevent the inclusion of one or more other through holes in the pad, for example, through holes for providing a polishing solution to pass upward through the polishing layer to the working surface or a path for gas flow through the pad. A through hole is defined as a hole that passes through the entire thickness Y of the bottom surface region 14.

[0057] In some embodiments, the polishing layer does not contain through-holes. Since the pad is typically mounted to another substrate (e.g., a subpad or platen) via an adhesive (e.g., a pressure sensitive adhesive) during use, the through-holes may allow the polishing solution to leak through the pad to the pad-adhesive interface. The polishing solution may be corrosive to the adhesive and cause a detrimental loss of bonding integrity between the pad and the substrate to which it is attached.

[0058] The depth Dp of the plurality of precisely formed holes 16 may be less than about 5 mm, less than about 1 mm, less than about 500 microns, less than about 200 microns, less than about 100 microns, less than about 90 microns, less than about 80 microns, less than about 70 microns, or even less than about 60 microns. The depth of the precisely formed holes 16 may be greater than about 1 micron, greater than about 5 microns, greater than about 10 microns, greater than about 15 microns, or even greater than about 20 microns. The depth of the plurality of precisely formed holes may be between about 1 micron and about 5 mm, between about 1 micron and about 1 mm, between about 1 micron and about 500 microns, between about 1 micron and about 200 microns, between about 1 micron and about 100 microns, between 5 microns and about 5 mm, between about 5 microns and about 1 mm, between about 5 microns and about 500 microns, between about 5 microns and about 200 microns, or even between about 5 microns and about 100 microns. The precisely formed holes 16 may all have the same depth or the depth may vary between the precisely formed holes 16 or between different groups of precisely formed holes 16 .

[0059] In some embodiments, at least about 10%, at least about 30%, at least about 50%, at least about 70%, at least about 80%, at least about 90%, at least about 95%, or even at least about 100% of the plurality of precisely formed holes have a depth between about 1 micron and about 500 microns, between about 1 micron and about 200 microns, between about 1 micron and about 150 microns, between about 1 micron and about 100 microns, between about 1 micron and about 80 microns, between about 1 micron and about 60 microns, between about 5 microns and about 500 microns, between about 5 microns and about 200 microns, between about 5 microns and about 150 microns, between about 5 microns and about 100 microns, between about 5 microns and about 80 microns, between about 5 microns and about 60 microns, between about 10 microns and about 200 microns, between about 10 microns and about 150 microns, or even between about 10 microns and about 100 microns.

[0060] In some embodiments, up to and including the entirety of at least a portion of the plurality of precisely shaped holes has a depth less than the depth of at least a portion of at least one macro-channel. In some embodiments, at least about 50%, at least about 60%, at least about 70%, at least about 80%, at least about 90%, at least about 95%, at least about 99%, or even at least about 100% of the plurality of precisely shaped holes has a depth less than the depth of at least a portion of the macro-channel.

[0061] The precisely formed pores 16 may be uniformly distributed across the surface of the polishing layer 10, i.e., have a single area density, or may have different area densities across the surface of the polishing layer 10. The area density of the precisely formed pores 16 may be less than about 1,000,000 / mm 2 , less than about 500,000 / mm 2 , less than about 100,000 / mm 2 , less than about 50,000 / mm 2 , less than about 10,000 / mm 2 , less than about 5,000 / mm 2 , less than about 1,000 / mm 2 , less than about 500 / mm 2 , less than about 100 / mm 2 , less than about 50 / mm 2 , less than about 10 / mm 2 or even less than about 5 / mm 2 The area density of the precisely formed holes 16 may be greater than about 1 / dm 2 , can be greater than about 10 / dm 2 , can be greater than about 100 / dm 2 , can be greater than about 5 / cm 2 , can be greater than about 10 / cm2 , can be greater than about 100 / cm 2 Or even greater than about 500 / cm 2 .

[0062] The ratio of the total cross-sectional area of ​​the precisely shaped hole openings 16c to the projected polishing pad surface area may be greater than about 0.5%, greater than about 1%, greater than about 3%, greater than about 5%, greater than about 10%, greater than about 20%, greater than about 30%, greater than about 40%, or even greater than about 50%. The ratio of the total cross-sectional area of ​​the precisely shaped hole openings 16c to the projected polishing pad surface area may be less than about 90%, less than about 80%, less than about 70%, less than about 60%, less than about 50%, less than about 40%, less than about 30%, less than about 25%, or even less than about 20%. The projected polishing pad surface area is the area resulting from projecting the shape of the polishing pad onto a plane. For example, a polishing pad having a circular shape with a radius r will have a projected surface area of ​​π times the radius squared, i.e., the area of ​​the circle projected on the plane.

[0063] The precisely shaped holes 16 may be randomly arranged on the surface of the polishing layer 10 or may be arranged in a pattern (eg, a repeating pattern) on the polishing layer 10. Patterns include, but are not limited to, square arrays, hexagonal arrays, etc. Combinations of patterns may be used.

[0064] The shape of the precisely formed protrusion 18 is not particularly limited and includes, but is not limited to, a cylinder, a hemisphere, a cube, a rectangular prism, a triangular prism, a hexagonal prism, a triangular pyramid, a 4-sided, 5-sided and 6-sided pyramid, a truncated pyramid, a cone, a truncated cone, and the like. The intersection of the precisely formed protrusion sidewall 18a and the bottom area 14 is considered the base of the protrusion. The highest point of the precisely formed protrusion 18 as measured from the protrusion base 18c to the top 18b is considered the top of the protrusion and the distance between the top 18b and the protrusion base 18c is the height of the protrusion. The shape of all the precisely formed protrusions 18 may be the same, or a combination may be used. In some embodiments, at least about 10%, at least about 30%, at least about 50%, at least about 70%, at least about 90%, at least about 95%, at least about 97%, at least about 99%, or even at least about 100% of the precisely formed protrusions are designed to have the same shape and size. Due to the precise manufacturing method used to make the precisely formed protrusions, tolerances are generally small. For a plurality of precisely formed protrusions designed to have the same protrusion size, the protrusion size is uniform. In some embodiments, the standard deviation of at least one distance dimension (e.g., height, width at the top, width at the base, length, and diameter) corresponding to the size of the plurality of precisely formed protrusions is less than about 20%, less than about 15%, less than about 10%, less than about 8%, less than about 6%, less than about 4%, less than about 3%, less than about 2%, or even less than about 1% of the mean value of the distance dimension. The standard deviation can be measured by known statistical techniques. The standard deviation can be calculated from a sample size of at least 5 protrusions, at least 10 protrusions, or even at least 20 protrusions, or even more protrusions. The sample size can be no more than 200 protrusions, no more than 100 protrusions, or even no more than 50 protrusions. The sample can be randomly selected from a single area on the polishing layer or from multiple areas of the polishing layer.

[0065] In some embodiments, at least about 50%, at least about 70%, at least about 90%, at least about 95%, at least about 97%, at least about 99%, and even at least about 100% of the precisely formed protrusions are solid structures. Solid structures are defined as containing less than about 10%, less than about 5%, less than about 3%, less than about 2%, less than about 1%, less than about 0.5%, or even 0% volume porosity. Porosity can include open or closed cell structures such as would be found, for example, in foams, or machined holes intentionally made in the protrusions by known techniques such as punching, drilling, die cutting, laser cutting, water jet cutting, etc. In some embodiments, the precisely formed protrusions do not contain machined holes. Due to the machining process, machined holes may have unwanted material deformation or accumulation near the edges of the holes, which can cause defects in the polished substrate surface (e.g., semiconductor wafer).

[0066] The longest dimension with respect to the cross-sectional area of ​​the precisely formed protrusion 18 (e.g., the diameter when the shape of the precisely formed protrusion 18 is cylindrical) may be less than about 10 mm, less than about 5 mm, less than about 1 mm, less than about 500 microns, less than about 200 microns, less than about 100 microns, less than about 90 microns, less than about 80 microns, less than about 70 microns, or even less than about 60 microns. The longest dimension of the precisely formed protrusion 18 may be greater than about 1 micron, greater than about 5 microns, greater than about 10 microns, greater than about 15 microns, or even greater than about 20 microns. The cross-sectional area of ​​the precisely formed protrusion 18 (e.g., the circle when the shape of the precisely formed protrusion 18 is cylindrical) may be uniform throughout the height of the protrusion; or the cross-sectional area may decrease if the precisely formed protrusion sidewall 18a tapers inwardly from the top of the protrusion to the base; or the cross-sectional area may increase if the precisely formed protrusion sidewall 18a tapers outwardly from the top of the protrusion to the base. Depending on the design, the precision-formed protrusions 18 may all have the same longest dimension or the longest dimension may vary between precision-formed protrusions 18 or between groups of different precision-formed protrusions 18. The width Wd of the top of the precision-formed protrusion base may be equal to the value given above for the longest dimension. The width of the precision-formed protrusion base may be equal to the value given above for the longest dimension.

[0067] The height of the precisely formed protrusions 18 may be less than about 5 mm, less than about 1 mm, less than about 500 microns, less than about 200 microns, less than about 100 microns, less than about 90 microns, less than about 80 microns, less than about 70 microns, or even less than about 60 microns. The height of the precisely formed protrusions 18 may be greater than about 1 micron, greater than about 5 microns, greater than about 10 microns, greater than about 15 microns, or even greater than about 20 microns. The precisely formed protrusions 18 may all have the same height or the height may vary between the precisely formed protrusions 18 or between groups of different precisely formed protrusions 18. In some embodiments, the working surface of the polishing layer includes a first group of precisely formed protrusions and at least one second group of precisely formed protrusions, wherein the height of the first group of precisely formed protrusions is greater than the height of the second group of precisely formed protrusions. Having multiple groups of multiple precisely formed protrusions (each group having different heights) can provide different planes of polishing protrusions. This can become particularly advantageous in the following situations: the surface of the protrusions has been modified to be hydrophilic, and after some degree of polishing, the first set of protrusions is worn (including removal of the hydrophilic surface), thereby allowing the second set of protrusions to contact the substrate being polished and provide new protrusions for polishing. The second set of protrusions may also have a hydrophilic surface and enhanced polishing performance compared to the worn first set of protrusions. The height of the first plurality of precisely formed protrusions may be between 3 microns and 50 microns, between 3 microns and 30 microns, between 3 microns and 20 microns, between 5 microns and 50 microns, between 5 microns and 30 microns, between 5 microns and 20 microns, between 10 microns and 50 microns, between 10 microns and 30 microns, or even between 10 microns and 20 microns, compared to the height of at least one of the second plurality of precisely formed protrusions.

[0068] In some embodiments, to facilitate utilization of the polishing solution at the polishing layer-polishing substrate interface, at least about 10%, at least about 30%, at least about 50%, at least 70%, at least about 80%, at least about 90%, at least about 95%, or even at least about 100% of the plurality of precisely shaped protrusions have a height between about 1 micron and about 500 microns, between about 1 micron and about 200 microns, between about 1 micron and about 100 microns, between about 1 micron and about 80 microns, between about 1 micron and about 60 microns, between about 5 microns and about 500 microns, between about 5 microns and about 200 microns, between about 5 microns and about 150 microns, between about 5 microns and about 100 microns, between about 5 microns and about 80 microns, between about 5 microns and about 60 microns, between about 10 microns and about 200 microns, between about 10 microns and about 150 microns, between about 10 microns and about 100 microns, between about 5 microns and about 80 microns, between about 5 microns and about 60 microns, between about 10 microns and about 200 microns, between about 10 microns and about 150 microns, or even between about 10 microns and about 100 microns.

[0069] The precisely shaped protrusions 18 may be uniformly distributed on the surface of the polishing layer 10, i.e., have a single area density, or may have different area densities on the surface of the polishing layer 10. The area density of the precisely shaped protrusions 18 may be less than about 1,000,000 / mm 2 , less than about 500,000 / mm 2 , less than about 100,000 / mm 2 , less than about 50,000 / mm 2 , less than about 10,000 / mm 2 , less than about 5,000 / mm 2 , less than about 1,000 / mm 2 , less than about 500 / mm 2 , less than about 100 / mm 2 , less than about 50 / mm 2 , less than about 10 / mm 2 or even less than about 5 / mm 2 The area density of the precisely formed protrusions 18 may be greater than about 1 / dm 2 , can be greater than about 10 / dm 2 , can be greater than about 100 / dm 2 , can be greater than about 5 / cm 2 , can be greater than about 10 / cm 2 , can be greater than about 100 / cm 2 Or even greater than about 500 / cm 2 In some embodiments, the areal density of the plurality of precisely shaped protrusions is independent of the areal density of the plurality of precisely shaped holes.

[0070] The precisely shaped protrusions 18 may be randomly arranged on the surface of the polishing layer 10 or may be arranged in a pattern (eg, a repeating pattern) on the polishing layer 10. Patterns include, but are not limited to, square arrays, hexagonal arrays, etc. Combinations of patterns may be used.

[0071] The total cross-sectional area of ​​the tips 18b relative to the total projected polishing pad surface area may be greater than about 0.01%, greater than about 0.05%, greater than about 0.1%, greater than about 0.5%, greater than about 1%, greater than about 3%, greater than about 5%, greater than about 10%, greater than about 15%, greater than about 20%, or even greater than about 30%. The total cross-sectional area of ​​the tips 18b of the precisely shaped projections 18 relative to the total projected polishing pad surface area may be less than about 90%, less than about 80%, less than about 70%, less than about 60%, less than about 50%, less than about 40%, less than about 30%, less than about 25%, or even less than about 20%. The total cross-sectional area of ​​the base of the precisely shaped projections relative to the total projected polishing pad surface area may be the same as described for the tips.

[0072] The polishing layer itself can function as a polishing pad. The polishing layer can be in the form of a film that is wound on a core and is adopted in a "roll-to-roll" form during use. The polishing layer can also be manufactured into a single pad (e.g., a circular shaped pad), as discussed further below. According to some embodiments of the present specification, the polishing pad including the polishing layer may further include a subpad. Figure 2 A polishing pad 50 is shown, which includes a polishing layer 10 having a working surface 12 and a second surface 13 opposite the working surface 12, and a subpad 30 adjacent to the second surface 13 is shown. Optionally, a foam layer 40 is interposed between the second surface 13 of the polishing layer 10 and the subpad 30. The various layers of the polishing pad can be adhered together by any technique known in the art (including the use of adhesives, such as pressure sensitive adhesives (PSAs), hot melt adhesives, and field curing adhesives). In some embodiments, the polishing pad includes an adhesive layer adjacent to the second surface. Using a lamination process in conjunction with a PSA (e.g., a PSA transfer tape) is a specific process for adhering the various layers of the polishing pad 50. The subpad 30 can be any of those known in the art. The subpad 30 can be a single layer of relatively rigid material (e.g., polycarbonate) or a single layer of relatively compressible material (e.g., elastomeric foam). The subpad 30 may also have two or more layers and may include a substantially hard layer (e.g., a rigid material or a high modulus material such as polycarbonate, polyester, etc.) and a substantially compressible layer (e.g., an elastomer or elastic foam material). The hardness of the foam layer 40 may be between about 20 Shore D and about 90 Shore D. The thickness of the foam layer 40 may be between about 125 microns and about 5 mm or even between about 125 microns and about 1000 microns.

[0073] In some embodiments of the present specification including a subpad with one or more opaque layers, a small hole may be cut into the subpad to create a "window". The hole may be cut through the entire subpad or only through one or more opaque layers. The cut portion of the subpad or one or more opaque layers is removed from the subpad, thereby allowing light to be transmitted through this area. The hole is repositioned to align with the endpoint window of the polishing tool platen and facilitates the use of the wafer endpoint detection system of the polishing tool by enabling light from the endpoint detection system of the tool to travel through the polishing pad and contact the wafer. Endpoint polishing detection systems based on light are known in the art and can be found on MIRRA and REFLEXION LKCMP polishing tools purchased from Applied Materials, Inc., Santa Clara, California, for example. The polishing pad of the present specification can be manufactured to run on such tools, and an endpoint detection window configured to work with the endpoint detection system of the polishing tool can be included in the pad. In one embodiment, a polishing pad including any of the polishing layers of the present specification can be laminated to the subpad. The subpad includes at least one rigid layer (e.g., polycarbonate) and at least one compliant layer (e.g., elastic foam), the elastic modulus of the rigid layer being greater than the elastic modulus of the compliant layer. The compliant layer may be opaque and prevent the transmission of light required for endpoint detection. The rigid layer of the subpad is typically laminated to the second surface of the polishing layer using a PSA (e.g., transfer adhesive and tape). Before or after lamination, holes may be die-cut or hand-cut in the opaque compliant layer of the subpad, for example, by a standard kiss-cutting method. The cut areas of the compliant layer are removed to create a "window" in the polishing pad. If adhesive residue is present in the hole opening, the residue may be removed, for example, by using an appropriate solvent and / or wiping with a cloth, etc. The "window" in the polishing pad is configured so that when the polishing pad is mounted to the polishing tool platen, the window of the polishing pad is aligned with the endpoint detection window of the polishing tool platen. The size of the hole may be, for example, up to 5 cm wide by 20 cm long. The size of the hole is typically the same or similar to the size of the endpoint detection window of the platen.

[0074] The thickness of the polishing pad is not specifically limited. The polishing pad thickness may be consistent with the desired thickness that can be polished on an appropriate polishing tool. The polishing pad thickness may be greater than about 25 microns, greater than about 50 microns, greater than about 100 microns, or even greater than 250 microns; less than about 20 mm, less than about 10 mm, less than about 5 mm, or even less than about 2.5 mm. The shape of the polishing pad is not specifically limited. The pad may be manufactured so that the pad shape is consistent with the shape of the corresponding platen of the polishing tool to which the pad will be attached during use. Pad shapes such as circular, square, hexagonal, etc. may be used. The maximum size of the pad (e.g., the diameter of a circular pad) is not specifically limited. The maximum size of the pad may be greater than about 10 cm, greater than about 20 cm, greater than about 30 cm, greater than about 40 cm, greater than about 50 cm, greater than about 60 cm; less than about 2.0 meters, less than about 1.5 meters, or even less than about 1.0 meters. As discussed above, a pad including a polishing layer, subpad, optional foam layer, and any combination thereof may include a window (ie, an area allowing light to pass through) to allow standard endpoint detection techniques used in the polishing process, such as wafer endpoint detection.

[0075] In some embodiments, the polishing layer can be a unitary sheet. The unitary sheet includes only a single material layer (i.e., it is not a multi-layered construction, e.g., a laminate), and the single material layer has a single composition. The composition may include multiple components, e.g., a polymer blend or a polymer-inorganic composite. Using a unitary sheet as a polishing layer can provide cost benefits due to minimizing the number of process steps required to form the polishing layer. The polishing layer including the unitary sheet can be manufactured according to techniques known in the art, including, but not limited to, molding and embossing. The unitary sheet is preferred because a polishing layer having precisely formed protrusions and / or precisely formed holes and optional macroscopic channels can be formed in a single step.

[0076] The hardness and flexibility of the polishing layer 10 are mainly controlled by the polyurethane used to make the polishing layer. The hardness of the polishing layer 10 is not specifically limited. The hardness of the polishing layer 10 may be greater than about 20 Shore D, greater than about 30 Shore D, or even greater than about 40 Shore D. The hardness of the polishing layer 10 may be less than about 90 Shore D, less than about 80 Shore D, or even less than about 70 Shore D. The hardness of the polishing layer 10 may be greater than about 20 Shore A, greater than about 30 Shore A, or even greater than about 40 Shore A. The hardness of the polishing layer 10 may be less than about 95 Shore A, less than about 80 Shore A, or even less than about 70 Shore A. The polishing layer may be flexible. In some embodiments, the polishing layer is capable of bending back on itself to produce a radius of curvature of less than about 10 cm, less than about 5 cm, less than about 3 cm, or even less than about 1 cm in the bending area; and greater than about 0.1 mm, greater than about 0.5 mm, or even greater than about 1 mm. In some embodiments, the polishing layer can bend back upon itself to produce a radius of curvature in the curved region of between about 10 cm and about 0.1 mm, between about 5 cm and about 0.5 mm, or even between about 3 cm and about 1 mm.

[0077] In order to improve the service life of the polishing layer 10, it is desirable to utilize a polyurethane having a high degree of toughness. This is particularly important due to the fact that the height of the precisely formed protrusions is small, but still needs to have a long service life in order to perform for a considerable period of time. The service life can be determined by the specific process of using the polishing layer. In some embodiments, the service life is at least 30 minutes, at least 60 minutes, at least 100 minutes, at least 200 minutes, at least 500 minutes or even at least 1000 minutes. The service life may be less than 10,000 minutes, less than 5,000 minutes or even less than 2,000 minutes. The length of the service life can be determined by measuring the final parameters relative to the final use process and / or the substrate being polished. For example, the service life can be determined by making the polished substrate have an average removal rate or a consistent removal rate (as measured by the standard deviation of the removal rate) within a specific time period (as defined above) or producing a consistent surface finish on the substrate within a specific time period. In some embodiments, the polishing layer can provide a standard deviation of the removal rate of the polished substrate between about 0.1% and 20%, between about 0.1% and about 15%, between about 0.1% and about 10%, between about 0.1% and about 5%, or even between about 0.1% and about 3% over a period of at least about 30 minutes, at least about 60 minutes, at least about 100 minutes, at least about 200 minutes, or even at least about 500 minutes. The period can be less than 10,000 minutes. To this end, it is desirable to use polymer materials with high work to failure (also known as fracture stress energy), as shown by a large integrated area under the stress and strain curve measured by a typical tensile test (e.g., as outlined by ASTM D638). High work to failure may be associated with lower wear materials. In some embodiments, the work to failure is greater than about 3 joules, greater than about 5 joules, greater than about 10 joules, greater than about 15 joules, greater than about 20 joules, greater than about 25 joules, or even greater than about 30 joules. The work to failure may be less than about 100 Joules or even less than about 80 Joules.

[0078] The polyurethane used to make the polishing layer 10 can be used in a substantially purified form. The polyurethane material used to make the polishing layer 10 may include fillers known in the art. In some embodiments, the polishing layer 10 is substantially free of any inorganic abrasive (e.g., inorganic abrasive particles), that is, it is a polishing pad free of abrasives. Substantially free means that the polishing layer 10 contains less than about 10 volume %, less than about 5 volume %, less than about 3 volume %, less than about 1 volume % or even less than about 0.5 volume % of inorganic abrasive particles. In some embodiments, the polishing layer 10 is substantially free of inorganic abrasive particles. Abrasives can be defined as materials with a Mohs hardness greater than the Mohs hardness of the substrate being ground or polished. Abrasives can be defined as having a Mohs hardness greater than about 5.0, greater than about 5.5, greater than about 6.0, greater than about 6.5, greater than about 7.0, greater than about 7.5, greater than about 8.0 or even greater than about 9.0. It is generally recognized that the maximum Mohs hardness is 10. The polishing layer 10 can be manufactured by any technique known in the art. Microreplication technology is disclosed in US Pat. Nos. 6,285,001; 6,372,323; 5,152,917; 5,435,816; 6,852,766; 7,091,255 and US Patent Application Publication No. 2010 / 0188751, which are incorporated by reference in their entirety.

[0079] In some embodiments, the polishing layer 10 is formed by the following method. First, a polycarbonate sheet is laser ablated according to the procedure described in U.S. Pat. No. 6,285,001 to form a positive master tool, i.e., a tool having a surface topography approximately the same as the desired surface topography of the polishing layer 10. The polycarbonate master is then nickel plated using conventional techniques to form a negative master tool. The nickel negative master tool can then be used in an embossing process (e.g., the process described in U.S. Patent Application Publication No. 2010 / 0188751) to form the polishing layer 10. The embossing process can include extruding a polyurethane melt onto the surface of a nickel negative mold and pressing the polyurethane melt into the topographical features of the nickel negative mold under appropriate pressure. After the polyurethane melt cools, the solid polymer film can be removed from the nickel negative mold to form a polishing layer 10 having a working surface 12, wherein the working surface has the desired topographical features, i.e., precisely formed holes 16 and / or precisely formed protrusions 18 ( Figure 1 ). Macro-channels may be formed in the polishing layer 10 by an embossing process if the negative mold includes an appropriate negative mold topography corresponding to the desired pattern of macro-channels.

[0080] In another embodiment, the present specification relates to a polishing system comprising any of the previous polishing pads and a polishing solution. The polishing pad may include any of the previously disclosed polishing layers 10. The polishing solution used is not specifically limited and may be any of those known in the art. The polishing solution may be aqueous or non-aqueous. An aqueous polishing solution is defined as a polishing solution having a liquid phase containing at least 50% by weight of water (if the polishing solution is a slurry, the liquid phase does not include particles). A non-aqueous solution is defined as a polishing solution having a liquid phase containing less than 50% by weight of water. In some embodiments, the polishing solution is a slurry, that is, a liquid containing organic or inorganic abrasive particles or a combination thereof. The concentration of organic or inorganic abrasive particles or a combination thereof in the polishing solution is not specifically limited. The concentration of organic or inorganic abrasive particles or a combination thereof in the polishing solution may be greater than about 0.5 wt%, greater than about 1 wt%, greater than about 2 wt%, greater than about 3 wt%, greater than about 4 wt%, or even greater than about 5 wt%; may be less than about 30 wt%, less than about 20 wt%, less than about 15 wt%, or even less than about 10 wt%. In some embodiments, the polishing solution is substantially free of organic or inorganic abrasive particles. "Substantially free of organic or inorganic abrasive particles" means that the polishing solution contains less than about 0.5 wt%, less than about 0.25 wt%, less than about 0.1 wt%, or even less than about 0.05 wt% of organic or inorganic abrasive particles. In one embodiment, the polishing solution may not contain organic or inorganic abrasive particles. The polishing system may include: a polishing solution, such as a slurry, for silicon oxide CMP (including but not limited to shallow trench isolation CMP); a polishing solution, such as a slurry, for metal CMP (including but not limited to tungsten CMP, copper CMP, and aluminum CMP); a polishing solution, such as a slurry, for barrier material CMP (including but not limited to tantalum and tantalum nitride CMP); and a polishing solution, such as a slurry, for polishing a hard substrate (such as sapphire). The polishing system may also include a substrate to be polished or ground.

[0081] In some embodiments, the polishing pad of the present description may include at least two polishing layers, ie, a multilayer arrangement of the polishing layer. The polishing layer including the polishing pad having the multilayer arrangement of the polishing layer may include any of the polishing layer embodiments of the present description.

[0082] Figure 3An example of a polishing system 100 for utilizing a polishing pad and method according to some embodiments of the present specification is schematically illustrated. As shown, the system 100 may include a polishing pad 150 and a polishing solution 160. The system may also include one or more of the following: a substrate 110 to be polished or abraded, a platen 140, and a carrier assembly 130. An adhesive layer 170 may be used to attach the polishing pad 150 to the platen 140 and may be part of the polishing system. The polishing solution 160 may be a layer of solution disposed around a major surface (e.g., a working surface) of the polishing pad 150. The polishing pad 150 may be any of the polishing pad embodiments of the present specification and include at least one polishing layer (not shown) as described herein, and may optionally include a polishing layer as described for Figure 2 The polishing pad 50 of the polishing system 100 is a sub-pad and / or foam layer. The polishing solution is typically disposed on the working surface of the polishing layer of the polishing pad. The polishing solution may also be located at the interface between the substrate 110 and the polishing pad 150. During operation of the polishing system 100, the drive assembly 145 may rotate (arrow A) the platen 140 to move the polishing pad 150 to perform a polishing operation. The polishing pad 150 and the polishing solution 160 may define a polishing environment, either individually or in combination, that mechanically and / or chemically removes material from the major surface of the substrate 110 or polishes the major surface of the substrate. In order to polish the major surface of the substrate 110 with the polishing system 100, the carrier assembly 130 may press the substrate 110 against the polishing surface of the polishing pad 150 in the presence of the polishing solution 160. The platen 140 (and therefore the polishing pad 150) and / or the carrier assembly 130 are then moved relative to each other to translate the substrate 110 on the polishing surface of the polishing pad 150. The carrier assembly 130 can rotate (arrow B) and optionally traverse laterally (arrow C). Thus, the polishing layer of the polishing pad 150 removes material from the surface of the substrate 110. In some embodiments, an inorganic abrasive (e.g., inorganic abrasive particles) can be included in the polishing layer to facilitate the removal of material from the surface of the substrate. In other embodiments, the polishing layer is substantially free of any inorganic abrasive, and the polishing solution can be substantially free of organic or inorganic abrasive particles or can include organic or inorganic abrasive particles or a combination thereof. It should be understood that Figure 3 The polishing system 100 is merely one example of a polishing system that may be employed in conjunction with the polishing pads and methods of the present description, and other conventional polishing systems may be employed without departing from the scope of the present description.

[0083] In another embodiment, the present specification is directed to a method of polishing a substrate, the method of polishing comprising: providing a polishing pad according to any of the previous polishing pads, wherein the polishing pad may include any of the previously described polishing layers; providing a substrate, contacting the working surface of the polishing pad with the substrate surface, moving the polishing pad and the substrate relative to each other while maintaining contact between the working surface of the polishing pad and the substrate surface, wherein polishing is performed in the presence of a polishing solution. In some embodiments, the polishing solution is a slurry and may include any of the previously discussed slurries. In another embodiment, the present specification is directed to any of the foregoing methods of polishing a substrate, wherein the substrate is a semiconductor wafer. The material comprising the semiconductor wafer surface to be polished (i.e., in contact with the working surface of the polishing pad) may include, but is not limited to, at least one of a dielectric material, a conductive material, a barrier / adhesion material, and a capping material. The dielectric material may include at least one of an inorganic dielectric material (e.g., silicon oxide and other glasses) and an organic dielectric material. The metal material may include, but is not limited to, at least one of copper, tungsten, aluminum, silver, etc. The capping material may include, but is not limited to, at least one of silicon carbide and silicon nitride. The barrier / adhesion material may include, but is not limited to, at least one of tantalum and tantalum nitride. The method of polishing may also include a pad conditioning or cleaning step, which may be performed in situ, i.e., during polishing. Pad conditioning may use any pad conditioner or brush known in the art, such as the 4.25 inch diameter 3M CMP PAD CONDITIONER BRUSH PB33A available from 3M Company, St. Paul, Minnesota. Cleaning may use a brush, such as the 4.25 inch diameter 3M CMP PAD CONDITIONER BRUSH PB33A available from 3M Company, St. Paul, Minnesota, and / or rinse the polishing pad with water or a solvent.

[0084] Example

[0085] Table 1: Materials

[0086]

[0087] Test Method

[0088] Universal Micro-Compounder Polymerization Method

[0089] Thermoplastic polyurethanes were prepared using an MC15 micro-compounder (Xplore Instruments, Sittard, The Netherlands). Polyols, chain extenders, isocyanates, and amines (per the compositions shown in Tables 2 and 3) were added to the micro-compounder with a total charge of 15 mL. The reactive mixture was mixed for five minutes at a screw speed of 100 RPM and a temperature setting of 210° C. to allow polymerization to occur. The resulting polymer was then pressed into flat sheets using a hydraulic press at 375° F.

[0090] Melt Viscosity Measurement

[0091] Melt viscosity was measured using a DHR-2 rheometer (TA Instruments, New Castle, DE). Polymer disks with a thickness between 1.0 mm and 2.0 mm and a diameter of 8 mm were dried in a 100°C oven and stored in vials with desiccant. The samples were mounted in the rheometer with 8 mm diameter parallel plates. The samples were tested using a temperature ramp from 150°C to 240°C, oscillations of 1% strain and an angular frequency of 1.0 rad / s. The complex viscosity measured at 200°C was recorded.

[0092] Example 1 to Example 8

[0093] Examples 1 to 8 were prepared using a universal micro-compounder polymerization process according to the compositions of Table 2. The viscosities of the resulting materials are also shown in Table 2. These examples show that the melt viscosity of the resin is controlled by the decanol content and that the melt viscosity is relatively insensitive to changes in the isocyanate index between 0.996 and 1.029.

[0094] Table 2. Composition of the reactive mixture (values ​​in wt %)

[0095]

[0096] Comparative Example 9

[0097] PolyTHF650 (4.60 g, 0.0142 equivalents), Chimassorb 944 (10.62 g, 0.0071 equivalents) and 4,4'-MDI (1.77 g, 0.0142 equivalents) were added to a MC15 micro-compounder. In this formulation, hydroxyl groups and amine end groups are 0.0071 equivalents more than isocyanate groups, so the resulting polymer is expected to have an end group concentration of 0.47 mol / kg, where the end groups are hydroxyl groups or amine groups. The reactive mixture was processed at 150 ° C and 100 RPM screw speed in a micro-compounder. After 1.5 minutes, a portion of the material was collected. FTIR analysis of the sample showed no remaining isocyanate peaks. After a total reaction time of 5 minutes, another portion of the material was collected. After a reaction time of 15 minutes, the remaining material was collected. The three samples were dissolved in CDCl3. Utilize 500MHz NMR to collect1H proton spectrum, and this 500MHz NMR is to use low top cone angle (15 degree) and 4 seconds of relaxation delay time (equipped with broadband cryoprobe AVANCE III 500MHz spectrometer, from Bruker (Billerica, MA) of Billerica, Massachusetts).In the obtained spectrum, the peak at 3.65ppm is attributed to the methylene group of the hydroxyl terminal α position that has not yet reacted with isocyanate.The peak at 2.65ppm is attributed to the methylene group of the amine terminal α position of Chimassorb 944 that has not yet reacted with isocyanate.The peak at 4.16ppm is attributed to the methylene group of the carbamate group α position formed by PolyTHF 650 and MDI reaction.The integration of these characteristic peaks is used to calculate the concentration of unreacted hydroxyl groups, unreacted amine terminal groups and carbamate groups at each time point. The results in Table 3 show that during the course of the reaction, the hydroxyl group concentration decreased by 0.094 mol / kg, while the amine concentration increased by 0.064 mol / kg, and the carbamate concentration increased by 0.075 mol / kg. This is consistent with a shift from a kinetically favorable product of urea groups and excess hydroxyl end groups to a more thermally stable product of carbamate groups and excess amine end groups.

[0098] Example 10

[0099] PolyTHF650 (2.34 g, 0.0072 equivalents), Chimassorb 944 (10.81 g, 0.0072 equivalents), decanol (1.14 g, 0.0072 equivalents) and 4,4'-MDI (2.71 g, 0.0216 equivalents) were added to a MC15 micro-compounder. In this case, there are an equal number of isocyanate equivalents and equivalents of hydroxyl groups and reactive amine groups. Therefore, the resulting polymer is expected to have only decanol-terminated end groups, and the expected end group concentration is 0.48 mol / kg, which is similar to the end group concentration in Comparative Example 9. The same method as used in Comparative Example 9 was performed on the reactive mixture, and the resulting concentrations of hydroxyl end groups, amine end groups, and carbamate at each time point are shown in Table 3. During the reaction process, the concentrations of hydroxyl end groups, amine end groups and carbamate end groups remained relatively unchanged (decreased by 0.008 mol / kg, 0.010 mol / kg and 0.013 mol / kg respectively), indicating that the polymer structure of Example 10 is chemically more stable than the polymer structure of Comparative Example 9.

[0100] Table 3. Concentration of functional groups as a function of treatment time

[0101]

[0102] Reactive Extrusion Method of Example 11 and Comparative Example 12

[0103] Example 11 and Example 12 (comparison) were prepared using conventional reactive extrusion techniques. Polyurethanes were prepared according to the formulations shown in Table 4 using a ZE40A twin screw extruder (with 7 barrel sections, each barrel having a diameter of 5 cm) purchased from Berstorff Corp., Florence KY. In the following discussion, the first barrel is closest to the extruder drive mechanism, and the seventh barrel is closest to the exit of the extruder. Fomrez 44-111 was added to the first barrel section via a heated ZENITH B-9000 gear pump (purchased from Circor International, Inc., Burlington, MA). 1,4-Butanediol was added to the first barrel section by a second ZENITH B-9000 gear pump. DBTL was added to the first barrel section via a PHD ULTRA HPSI / XF syringe pump (purchased from Harvard Apparatus, Holliston, MA). Decyl alcohol was added to the first barrel section and metered using a Tuthill D-series gear pump purchased from Ingersoll Rand, Inc. Rubinate 1234 was added to the second barrel section via a third ZEITH B-9000 gear pump. Chimassorb 944 was metered into the side filler unit via a Ktron loss-in-weight feeder purchased from Coperion, Pittman, NJ. The side filler delivered Chimassorb 944 to barrel section 4. The molten polyurethane was discharged from the extruder into a ZENITH PEP II gear pump (purchased from Circor International, Inc) operated at approximately 20 cm3 / min. The polyurethane was pumped into an underwater pelletizer (Model EUP10, available from ECON Inc. Monroe, MI). The polyurethane was produced at a rate of approximately 100 lb / hr (45 kg / hr).

[0104] Table 4. Composition of the reactive mixture (values ​​in wt %)

[0105] Components Embodiment 11 Comparative Example 12 Fomrez 44-111 34.07 34.4 1,4-Butanediol 7.24 7.2 Rubinate 1234 52.85 52.9 DBTDL 0.02 0.005 Chimassorb 944 5.50 5.5 Decyl alcohol 0.35 Isocyanate Index 1.015 1.02 Viscosity at 200°C (Pa s) 9578 32650

[0106] Embodiment 13

[0107] Example 13 was prepared using a universal micro-compounder polymerization process according to the composition of Fomrez 44-111 (33.9 wt %), 1,4-BDO (7.2 wt %), Rubinate 1234 (52.9 wt %), DBTDL (0.005 wt %), Chimassorb 944 (5.5 wt %) and 2-butyl-1-octanol (0.53 wt %). The viscosity of the resulting material at 200° C. was 2723 Pas.

[0108] Various modifications and alterations of this invention will become apparent to those skilled in the art without departing from the scope and spirit of this invention.

Claims

1. A polyurethane comprising the reaction product of a reactive mixture comprising Polyols; Diol chain extender; Diisocyanates; Monohydric alcohol; and A polyfunctional amine according to at least one of formula I and formula II in, X is an integer from 0 to 10, inclusive, R1 is a linear or branched aliphatic group, a cyclic aliphatic group, an aromatic group, or a compound containing an aromatic group having 2 to 20 carbon atoms, R2 is a straight or branched alkyl group having 1 to 20 carbon atoms, R2' is hydrogen or a straight or branched chain alkyl group having 1 to 20 carbon atoms; and The molar ratio of isocyanate groups to hydroxyl groups in the reactive mixture is 0.98 or greater.

2. The polyurethane according to claim 1, wherein the monohydric alcohol is a fatty alcohol.

3. The polyurethane according to claim 2, wherein the fatty alcohol is a C6-C12 fatty alcohol.

4. The polyurethane according to claim 2, wherein the fatty alcohol is 1-decanol. 5 . A polishing pad comprising a polishing layer having a working surface and a second surface opposite to the working surface, wherein the polishing layer comprises the polyurethane according to claim 1 . 6 . The polishing pad of claim 5 , wherein the polishing layer comprises greater than 90 wt % of the polyurethane of claim 1 .

7. The polishing pad of claim 5, wherein the working surface comprises a bottom surface region and at least one of a plurality of precisely shaped holes and a plurality of precisely shaped protrusions.

8. The polishing pad according to claim 5, wherein the polishing layer further comprises a plurality of independent or interconnected macro channels. 9 . The polishing pad of claim 5 , further comprising a subpad, wherein the subpad is adjacent to the second surface of the polishing layer.

10. The polishing pad of claim 5, wherein the polishing layer comprises less than 1 volume % of inorganic abrasive particles. 11 . A polishing system comprising a polishing solution and the polishing pad according to claim 5 .

12. The polishing system of claim 11, wherein the polishing solution is a slurry.

13. A method for polishing a substrate, the method comprising: Providing a polishing pad according to claim 5; providing a substrate; contacting the working surface of the polishing layer with a substrate surface; The polishing pad and the substrate are moved relative to each other while maintaining contact between the working surface of the polishing pad and the substrate surface, wherein polishing is performed in the presence of a polishing solution.

14. The method for polishing a substrate according to claim 13, wherein the polishing solution is a slurry.

15. The method for polishing a substrate according to claim 13, wherein the substrate is a semiconductor wafer.

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