Chemical mechanical polishing pad with disulfide bridges

Abstract

The precursor for preparing a chemical mechanical polishing pad includes a prepolymer, a disulfide-containing component, and a curing agent. The chemical mechanical polishing pad prepared from the precursor includes disulfide bridges in the polymer matrix. The disulfide bridges can include disulfide bonds that can undergo chain exchange reactions at temperatures experienced during the chemical mechanical polishing process, resulting in the rearrangement of nearby disulfide bonds rather than the destruction of these bonds during the chemical mechanical polishing process.

Description

[Technical Field]

[0001] The present disclosure relates generally to chemical mechanical polishing pads, and more particularly to chemical mechanical polishing pads having disulfide bridges. [Background technology]

[0002] Integrated circuits are typically formed on substrates by sequentially depositing conductive, semiconductive, and / or insulating layers on silicon wafers. Various manufacturing processes require polishing or planarizing at least one of these layers on a substrate. For example, in certain applications (e.g., polishing a metal layer to form vias, plugs, and lines within trenches in a patterned layer), the overlying layer is planarized until the top surface of the patterned layer is exposed. In other applications (e.g., polishing a dielectric layer for photolithography), the overlying layer is polished until a desired thickness remains above the underlying layer. Chemical-mechanical polishing (CMP) is one method of surface planarization. This method typically involves mounting a substrate on a carrier head. The exposed surface of the substrate is typically placed against a polishing pad on a rotating platen. The carrier head applies a controllable load (e.g., downward force) to the substrate to press it against the rotating polishing pad. A polishing fluid, such as a slurry containing abrasive particles, can also be applied to the surface of the polishing pad during polishing. Summary of the Invention

[0003] CMP pads are subjected to significant thermal and mechanical stresses during the CMP process. These stresses can cause failure of conventional CMP pad materials, resulting in a shortened CMP pad lifespan and degradation and / or inconsistency over time. The present disclosure provides improved CMP pads made of materials with disulfide bridges in a polyurethane matrix. The disulfide bridges can include disulfide bonds capable of undergoing chain exchange reactions at temperatures experienced during chemical mechanical polishing processes, resulting in rearrangement of nearby disulfide bonds rather than the rupture of these bonds during the chemical mechanical polishing process. The improved CMP pads have improved lifespans and improved polishing performance under CMP conditions (i.e., at high temperatures and high mechanical stresses). The improved CMP pads of the present disclosure can have improved material removal rates compared to those achieved by previous CMP pads, and these improved removal rates can be maintained over longer use of the improved CMP pads.

[0004] In one embodiment, a precursor for preparing a chemical mechanical polishing pad includes a prepolymer, a disulfide-containing component, and a curing agent. Furthermore, the prepolymer may be a polyurethane prepolymer. The prepolymer may include a polyisocyanate. The prepolymer may include polytetrahydrofuran and toluene diisocyanate. The weight percent of the prepolymer ranges from 60% to 80%. The disulfide-containing component may include 2-hydroxyethyl disulfide. The weight percent of the disulfide component may range from 2.5% to 7.5%. The curing agent may be dimethylthiotoluenediamine. The precursor may further include one or more pore fillers.

[0005] In another embodiment, the chemical mechanical polishing pad includes a polishing surface, the polishing surface including a material containing disulfide bridges in a polymer matrix. Further, the polymer matrix may be a polyurethane matrix. The material containing disulfide bridges may include disulfide bonds that can undergo chain exchange reactions at temperatures experienced during the chemical mechanical polishing process, resulting in bond rearrangement during the chemical mechanical polishing process.

[0006] In yet another embodiment, a method for preparing a chemical mechanical polishing pad includes preparing a precursor by combining a prepolymer, a disulfide-containing component, and a curing agent; casting the precursor at a first temperature; and curing the cast precursor at a second temperature. The method may further include mixing the combined prepolymer, disulfide-containing component, and curing agent for less than one minute before casting the precursor. The first temperature may be higher than the second temperature. The method may further include combining the prepolymer with one or more additives, such as a pore filler. The prepolymer may be a polyurethane prepolymer. The prepolymer may include a polyisocyanate. The prepolymer may include polytetrahydrofuran and toluene diisocyanate. The weight percent of the prepolymer ranges from 60% to 80%. The disulfide-containing component may include 2-hydroxyethyl disulfide. The weight percent of the disulfide component may range from 2.5% to 7.5%. The curing agent may be dimethylthiotoluenediamine.

[0007] For an aid in understanding the present disclosure, reference is now made to the following descriptions taken in conjunction with the accompanying drawings. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a diagram of an exemplary system for chemical mechanical polishing (CMP). [Figure 2]FIG. 1 is a reaction diagram of an exemplary reaction for preparing a CMP pad having disulfide crosslinks and a polyurethane matrix. [Figure 3] FIG. 2 is a reaction diagram of an exemplary thermally induced transformation of a disulfide bridge-containing component of a CMP pad during use of the CMP pad. [Figure 4] FIG. 2 is a block diagram of an exemplary composition of precursors for preparing a CMP pad that can be used in the system of FIG. 1. [Figure 5] 1 is a flow chart of an exemplary process for preparing a CMP pad. [Figure 6] 1 is a plot of the removal rates achieved by the improved CMP pad of the present disclosure and previous CMP pads under different polishing conditions. [Figure 7] 1 is a graph of the removal rates achieved by different improved CMP pads of the present disclosure using different abrasive slurries. [Figure 8] 1 is a graph of the removal rates achieved by different improved CMP pads of the present disclosure using different abrasive slurries. [Figure 9] 1A and 1B are plots of the CMP pad temperature and torque achieved during a polishing process using an improved CMP pad of the present disclosure and a previous CMP pad, respectively. [Figure 10] 1A and 1B are plots of the CMP pad temperature and torque achieved during a polishing process using an improved CMP pad of the present disclosure and a previous CMP pad, respectively. DETAILED DESCRIPTION OF THE INVENTION

[0009] While exemplary implementations of embodiments of the present disclosure are illustrated below, it should be understood at the outset that the present disclosure can be implemented using any number of technologies, whether currently known or not. The present disclosure should in no way be limited to the exemplary implementations, drawings, and technologies illustrated below. Additionally, the drawings are not necessarily drawn to scale.

[0010] The present disclosure recognizes that conventional materials used to prepare CMP pads face problems of insufficient lifespan due to wear and degradation of the CMP pad during their use in the CMP process. For example, previous polyurethane-based CMP pads wear and degrade during the CMP process, which experiences severe mechanical and thermal stresses. The high surface temperatures experienced during the CMP process can lead to the destruction of previous CMP pads, resulting in reduced performance and a reduced usable lifespan. The present disclosure provides an improved CMP pad with self-healing properties. The CMP pad of the present disclosure is prepared from a precursor that includes a disulfide-containing component along with a prepolymer and a curing agent. The disulfide bonds in the resulting material can undergo chain exchange reactions at temperatures experienced during the CMP process, resulting in bond rearrangement rather than bond breaking during the CMP process. This rearrangement facilitates improved CMP pad performance and lifespan.

[0011] Chemical Mechanical Polishing (CMP) System FIG. 1 illustrates a system 100 for performing chemical mechanical polishing. The system 100 includes a CMP pad 102 (also referred to as a "polishing pad") disposed on or attached to a platen 104. For example, an adhesive layer (not shown) can be used to attach the polishing pad to the platen 104. The platen 104 can generally rotate during chemical mechanical polishing. A wafer 106 (e.g., a silicon wafer with or without conductive, semiconductive, and / or insulating layers, as described above) is attached to a rotatable chuck head 108. The wafer 106 may be attached using a vacuum and / or a reversible adhesive (e.g., an adhesive that holds the wafer 106 in place during chemical mechanical polishing but allows the wafer 106 to be removed from the head 108 after chemical mechanical polishing). As shown in FIG. 1, pressure can be applied to the wafer 106 during chemical mechanical polishing (e.g., to facilitate contact between the surface of the wafer 106 and the CMP pad 102). As will be further explained below, the improved CMP pad 102 of the present disclosure can allow for effective polishing while reducing the applied downward pressure.

[0012] 2 and 3, described below, illustrate an exemplary polishing pad 102, along with the chemical reactions associated with the formation and resilience of the CMP pad 102 during use in a CMP process. With further reference to FIG. 1, the CMP pad 102 generally has a circular or generally cylindrical shape (i.e., having a top surface, a bottom surface, and curved edges). As described in more detail with respect to FIGS. 2-10 below, at least the top polishing surface of the CMP pad 102 comprises a matrix of polyurethane chains connected by disulfide bonds. An exemplary composition of a precursor used to prepare the exemplary polishing pad 102 is described in more detail below with respect to FIGS. 2 and 4. The CMP pad 102 can have any suitable thickness and any suitable diameter (e.g., for use in a CMP system such as system 100). For example, the thickness of the CMP pad 102 can range from about 0.5 millimeters to more than 5 centimeters. In some embodiments, the thickness of the polishing pad can range from 1 millimeter to 5 millimeters. The polishing pad 102 can be prepared using any suitable manufacturing process, including, for example, cast-based manufacturing processes, additive manufacturing processes, etc. The diameter of the polishing pad may be selected to match or be slightly smaller than the diameter of the platen 104 of the polishing system 100 being used. The CMP pad 102 generally has a uniform thickness (e.g., a thickness that varies by 50%, 25%, 20%, 10%, 5%, or less over the radial extent of the polishing pad).

[0013] A slurry 110 can be applied to the surface of the CMP pad 102 before and / or during chemical mechanical polishing. The slurry 110 can be any suitable slurry for polishing the wafer type and / or layer material to be planarized (e.g., for removing a silicon oxide layer from the surface of the wafer 106). The slurry 110 generally includes a fluid and abrasive particles and / or chemically reactive particles. Any suitable slurry 110 can be used. For example, the slurry 110 can react with one or more materials to be removed from the surface being planarized. The improved CMP pad 102 of the present disclosure facilitates both higher removal rates and longer life, even with more aggressive slurries such as W8902-CI45, which can reach relatively high temperatures during polishing.

[0014] The conditioner 112 is a device configured to condition the surface of the CMP pad 102. The conditioner 112 typically contacts the surface of the CMP pad 102 during chemical mechanical polishing and removes a portion of the top layer of the CMP pad 102 to improve its performance. For example, the conditioner 112 can roughen the surface of the CMP pad 102. Certain embodiments of the polishing pad described in this disclosure offer reduced conditioning requirements and improved resilience to repeated conditioning, thereby maintaining CMP performance with fewer or shorter conditioning steps and preserving the life of the CMP pad even after multiple conditioning.

[0015] Exemplary CMP Pad FIG. 2 illustrates an exemplary CMP pad 102 in more detail. The exemplary CMP pad 102 includes an upper polishing surface 212 that can include grooves and / or channels that can facilitate the movement of slurry (e.g., slurry 110 of FIG. 1 ) away from the surface 212 during a CMP process. At least the upper polishing surface 212 includes a material 206 that includes a matrix of polymers 208 a,b having disulfide bridges 210. The disulfide bridges 210 are sulfur-sulfur bonded coupling chains of the polymers 208 a,b, as shown in the exemplary chemical structure illustrated in FIG. 2. As further described with respect to FIG. 3 below, the sulfur-sulfur bonds of the disulfide bridges 210 can undergo a reaction with elevated temperature that improves the recovery of the material 206, resulting in a self-healing CMP pad 102 with improved service life and performance.

[0016] Material 206 can be prepared via reaction 200. In reaction 200, a prepolymer 202 reacts with a disulfide-containing component 204. Prepolymer 202 can be a polyisocyanate, such as toluene diisocyanate, as shown in the example of FIG. 2. Disulfide-containing component 204 can be 2-hydroxyethyl disulfide, as shown in the example of FIG. 2. Further details and examples of precursor components for preparing CMP pad 102 are described below with respect to FIGS. 4 and 5.

[0017] 3 illustrates an exemplary thermally activated reaction of molecules 302a, b of the material 206 of the exemplary CMP pad 102 during a CMP process. As discussed above, CMP pads, such as the CMP pad 102, experience elevated temperatures during a CMP process. Previous polymeric CMP pad materials could fail at these elevated temperatures (e.g., due at least in part to thermally induced bond breaking). In contrast, the disulfide bridges 210 of the improved CMP pad material 206 impart self-healing properties to the CMP pad 102.

[0018] For example, as shown in reaction 300 in FIG. 3 , molecules 302a and 302b of the initial CMP pad material 206 can undergo a radical-mediated reaction involving hemolytic cleavage of disulfide bridges 210 and subsequent radical migration of sulfur radicals to form new molecules 302c and 302d of thermally rearranged material 206′. Thus, rather than breaking down, molecules 302a and 302b can transfer polymer chains to form similar molecules 302c and 302d, thereby making the structure of the CMP pad 102 less susceptible to breakdown at elevated temperatures. This can facilitate improved performance and extended service life of the CMP pad 102 compared to previous CMP pads. For example, the microscale texture of the CMP pad 102 can be more effectively maintained at high temperatures because bonds are rearranged rather than broken down via reaction 300. In some cases, the CMP pad 102 may be used to remove materials that involve high CMP temperatures, such as tungsten.

[0019] Exemplary CMP Pad Precursors 4 shows an exemplary precursor 400 for preparing the CMP pad 102. The precursor 400 includes a prepolymer 402, a disulfide-containing component 404, a curing agent 406, and optionally one or more additives 408. The precursor 400 is an example and may include more or fewer components to meet the needs of a given application.

[0020] The prepolymer 402 may be a curable polyurethane prepolymer. As an example, the prepolymer 402 may be a toluene diisocyanate (TDI) prepolymer. For example, the TDI prepolymer may be based on polytetrahydrofuran (PTMEG), polyester, or PTMEG / polyester. The prepolymer 402 may also be a polyisocyanate, such as toluene diisocyanate. Examples of such prepolymers 402 are Imuthane PET-75D available from Coim International and 80DPLF available from Anderson Development Company. Another exemplary prepolymer 402 is prepolymer 202 in FIG. 2. In some cases, the precursor 400 includes 60% to 80% prepolymer 402 by weight. However, the prepolymer 402 may be added at a lower or higher concentration as appropriate for a given application.

[0021] The disulfide-containing component 404 is a component having a disulfide, i.e., a sulfur-sulfur bond. An example of a disulfide-containing component is the disulfide-containing component 204 shown in FIG. 2 above. For example, the disulfide-containing component can be 2-hydroxyethyl disulfide. In some cases, the precursor 400 contains 2.5% to 7.5% by weight of the disulfide-containing component 404. The precursor 400 contains 3.5% to 6.5% by weight of the disulfide-containing component 404. The precursor 400 contains 5% to 6% by weight of the disulfide-containing component 404. Examples of the disulfide-containing component 404 include allyl disulfide, 3,3'-dihydroxydiphenyl disulfide, 4-aminophenyl disulfide, penicillamine disulfide, bis(2-methacryloyl)oxyethyl disulfide, and bis(16-hydroxy-hexadecyl) disulfide. Examples of suitable phenyl disulfides include, but are not limited to, 4-nitrophenyl disulfide, bis(4-methoxyphenyl) disulfide, bis(10-carboxydecyl) disulfide, 2-(salicylideneamino)phenyl disulfide, and N,N'-bis(2-hydroxy-benzylidene)-4-aminophenyl disulfide.

[0022] The curing agent 406 is used to initiate polymerization of the prepolymer 402. In some cases, the curing agent 406 can initiate or accelerate this reaction at elevated temperature. As an example, the curing agent 406 may be dimethylthiotoluenediamine (DMTDA). The precursor 400 may contain 5%-20% by weight of the curing agent 406. 10-20%. However, the curing agent 406 may be added at lower or higher concentrations as appropriate for a given application. Examples of curing agents 406 include, but are not limited to, diamines such as 4,4'-methylenebis(orthochloroaniline), 2,6-diethyl-3-chloroaniline, 3,5-diethitoluene-2,4-diamine, 3,5-diethitoluene-2,6-diamine, and methylenebis(orthoethylaniline), and diols such as hydroquinone bis(2-hydroxyethyl) ether, 1,4-butanediol, 2,-methyl-1,3-propanediol, 1,3-propanediol, and 1,6-hexanediol.

[0023] The one or more additives 408 may include stabilizers, plasticizers, pore fillers, pigments, etc. For example, pore fillers are particles (e.g., microspheres) that expand in volume when heated. Pore fillers can cause the formation of voids in the polishing pad, which can improve pad performance by creating a porous structure in the polymer matrix formed by the cured prepolymer 402. Another exemplary additive 408 is carbon black, which is a substance used to add color to the formed CMP pad 102. The additive 408 is typically added at a weight percent of 1% to 30%. For example, the additive may be included at between 1% and 5% by weight. However, the additive 408 may be added at a lower or higher concentration as appropriate for a given application. In some cases, the precursor 400 does not include the additive 408.

[0024] Exemplary Methods for Preparing a CMP Pad 5 illustrates an exemplary process 500 for preparing a CMP pad 102 according to an exemplary embodiment of the present disclosure. The process 500 may begin at step 502, where a prepolymer 402 is combined with one or more additives 408. For example, the prepolymer 402 and the additive(s) 408 may be combined and mixed for a period of time. As an example, the prepolymer 402 and the additive(s) 408 may be combined and mixed at 160° F. for approximately two hours.

[0025] In step 504, the mixture from step 502 is combined with a disulfide-containing component 404 and a curing agent 406. The resulting mixture is mixed for a short time (e.g., about 1 minute or less) before proceeding to step 506, where the resulting mixture (i.e., precursor 400 of FIG. 4) is cast to prepare the CMP pad 102. By way of example, precursor 400 can be cast at 260° F. for about 10 minutes.

[0026] In step 508, the cast precursor 400 is cured at a temperature appropriate for curing the precursor 400 for a period of time. The curing in step 508 can be performed at the same or a different temperature than that used for casting in step 506. In some cases, the curing can be performed at a lower temperature than that used for casting. For example, the cast precursor 400 may be cured at 200°F for about 12 hours. The resulting CMP pad 102 can be used in a CMP pad process as described with respect to the example of FIG. 1 above.

[0027] Experimental example Using the improved precursors of the present disclosure, various exemplary CMP pads (Samples 1-3) were prepared, and their performance was compared to that of a control CMP pad. Table 1 below shows the compositions of the improved CMP pads, Samples 1-3, and the control CMP pad. The prepolymer was a PTMEG-based TDI (Imuthane PET-75D from Coim International for the control CMP pad and 80DPLF from Anderson Development Company for Samples 1-3). The disulfide-containing component was 2-hydroxyethyl disulfide from Sigma-Aldrich Company. The curing agent was DMTDA (Curene 107 from Anderson Development Company). The boron nitride powder additive was NX1 Powder 25 lb Count from Momentive Performance Materials. The pore-filler additive was Expancel 461 DE20 d70 from Nouryon Pulp and Performance Chemicals LLC. TIFF2025531359000002.tif37170

[0028] FIG. 6 shows a comparison of the removal rates of a 6 kÅ tungsten (W) blanket layer achieved by the Sample 2 CMP pad and the control CMP pad under different conditions of the amount of in situ conditioning (i.e., the relative duration of the conditioning step performed), the conditioning down force (“conditioner_df”, i.e., the force applied during conditioning in psi), and the polishing time in seconds. The Sample 2 CMP pad achieved a higher removal rate under milder conditioning conditions than those required for the control CMP pad. Thus, the Sample 2 CMP pad should provide improved performance over a longer CMP pad life while consuming less material to perform the conditioning step (e.g., because the conditioning step can be shorter and / or performed less frequently).

[0029] Figure 7 shows the tungsten removal rates of the Sample 1 CMP pad and the control CMP pad in two different chemical mechanical polishing slurries (W7300-B21 and W8902-CI45). W8902-CI45 is a more aggressive slurry that can more effectively remove tungsten, but it can also cause temperature increases during polishing. As shown in Figure 7, the Sample 1 CMP pad exhibited a higher removal rate than the control CMP pad, especially when using W8902-CI45. This further demonstrates the improved performance of the disclosed CMP pad for tungsten removal.

[0030] Figure 8 shows the tungsten removal rates of the CMP pads of Samples 2 and 3 and the control CMP pad when using the same two different chemical mechanical polishing slurries (W7300-B21 and W8902-CI45). As shown in Figure 8, when using W8902-CI45, the CMP pads of Samples 2 and 3 exhibited higher removal rates than the control CMP pad.

[0031] 9 and 10 show the temperatures and torques achieved during the CMP process using the control CMP pad and the Sample 1 CMP pad, respectively, for tungsten removal. The Sample 1 CMP pad was able to operate effectively at higher temperatures and torques than the control CMP pad. This ability to perform consistently well at higher temperatures and torques may be imparted, at least in part, by the self-healing properties of the CMP pads of the present disclosure, as described, for example, with respect to FIG. 3 above.

[0032] Modifications, additions, or omissions may be made to the systems, devices, and methods described herein. System and device components may be integrated or separated. Furthermore, system and device operations may be performed by more, fewer, or other components. Methods may include more, fewer, or other steps. Furthermore, steps may be performed in any suitable order. Furthermore, system and device operations may be performed using any suitable logic. As used herein, "each" refers to each member of a set or each member of a subset of a set.

[0033] As used herein, "or" is inclusive rather than exclusive, unless expressly stated otherwise or indicated otherwise by context. Thus, as used herein, "A or B" means "A, B, or both," unless expressly stated otherwise or indicated otherwise by context. Furthermore, "and" is both jointly and severally, unless expressly stated otherwise or indicated otherwise by context. Thus, as used herein, "A and B" means "A and B, jointly or severally," unless expressly stated otherwise or indicated otherwise by context.

[0034] The scope of the present disclosure encompasses all changes, substitutions, variations, alterations, and modifications to the exemplary embodiments described or illustrated herein that would be understood by a person skilled in the art. The scope of the present disclosure is not limited to the exemplary embodiments described or illustrated herein. Furthermore, although the present disclosure describes and illustrates each embodiment herein as including particular components, elements, features, functions, operations, or steps, any of these embodiments may include any combination or permutation of any of the components, elements, features, functions, operations, or steps described or illustrated anywhere herein that would be understood by a person skilled in the art. Furthermore, references in the appended claims to a device or system, or a component of a device or system, that is adapted, arranged, enabled, configured, enabled, operable, or operative to perform a particular function encompass that device, system, or component, so long as the device, system, or component is so adapted, arranged, enabled, configured, enabled, operative, or operative, regardless of whether it or that particular function is activated, turned on, or unlocked. Furthermore, although this disclosure describes or illustrates particular embodiments as providing certain advantages, a particular embodiment may not provide any, some, or all of those advantages.

[0035] The use of "a" and "an," as well as "the" and similar referents in the context of describing the present invention (particularly in the context of the claims below), should be construed to encompass both the singular and the plural, unless otherwise indicated herein or clearly contradicted by context. The terms "comprising," "having," "including," and "containing" should be construed as open-ended terms (i.e., meaning "including, but not limited to"), unless otherwise indicated. The recitation of ranges of values ​​herein is merely intended to serve as a shorthand method of referring individually to each separate value falling within the range, unless otherwise indicated herein, and each separate value is incorporated herein as if it were individually set forth herein. The use of any examples or exemplary language (e.g., "such as") provided herein is solely for the purpose of better illustrating the disclosure and does not impose limitations on the scope of the claims.

Claims

1. A precursor for preparing a chemical mechanical polishing pad, comprising: A prepolymer, a disulfide-containing component; and Hardener and , precursors.

2. The precursor of claim 1 , wherein the prepolymer is a polyurethane prepolymer.

3. The precursor of claim 1 , wherein the prepolymer comprises a polyisocyanate.

4. The precursor of claim 1 , wherein the prepolymer comprises polytetrahydrofuran and toluene diisocyanate.

5. 10. The precursor of claim 1, wherein the weight percent of the prepolymer ranges from 60% to 80%.

6. 2. The precursor of claim 1, wherein the disulfide-containing component comprises 2-hydroxyethyl disulfide.

7. 2. The precursor of claim 1, wherein the weight percentage of the disulfide component ranges from 2.5% to 7.5%.

8. 10. The precursor of claim 1, wherein the curing agent is dimethylthiotoluenediamine.

9. The precursor of claim 1 further comprising one or more pore fillers.

10. A chemical mechanical polishing pad comprising a polishing surface, the polishing surface comprising a material containing disulfide bridges in a polymer matrix.

11. The chemical mechanical polishing pad of claim 10 , wherein the polymer matrix is ​​a polyurethane matrix.

12. 11. The chemical mechanical polishing pad of claim 10, wherein the material containing the disulfide bridges contains disulfide bonds capable of undergoing a chain exchange reaction at temperatures experienced during a chemical mechanical polishing process, resulting in bond rearrangement during the chemical mechanical polishing process.

13. 1. A method for preparing a chemical mechanical polishing pad, comprising: preparing a precursor by combining a prepolymer, a disulfide-containing component, and a curing agent; casting the precursor at a first temperature; curing the cast precursor at a second temperature; A method comprising:

14. 14. The method of claim 13, further comprising mixing the combined prepolymer, disulfide-containing component, and curing agent for less than 1 minute before casting the precursor.

15. The method of claim 13 , wherein the first temperature is greater than the second temperature.

16. The method of claim 13 , wherein the prepolymer comprises a polyisocyanate.

17. The method of claim 13, wherein the weight percent of the prepolymer ranges from 60% to 80%.

18. 14. The method of claim 13, wherein the disulfide-containing component comprises 2-hydroxyethyl disulfide.

19. 14. The method of claim 13, wherein the weight percent of the disulfide component ranges from 2.5% to 7.5%.

20. 14. The method of claim 13, wherein the curing agent is dimethylthiotoluenediamine.

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