Polishing pad with filled non-porous secondary pad

Abstract

A polishing pad for chemical mechanical polishing includes a polishing layer and a secondary pad. The polishing layer has a polishing surface and a polishing layer interface surface opposite the polishing surface, and the polishing layer includes a polishing material. The secondary pad layer has a secondary pad interface surface adjacent the polishing layer interface surface and a bottom surface opposite the secondary pad interface surface, and the secondary pad layer includes a secondary pad material. The secondary cushion layer has an average compressive modulus of elasticity of 1 to 5 MPa at a pressure of 24 to less than 48 kPa and an average compressive modulus of elasticity of 5 to 20 MPa at a pressure of 48 to 76 kPa and a true strain of less than or equal to 10% at a compressive pressure of up to 1.2 MPa.

Description

Technical Field

[0001] The field of this invention is polishing pads for chemical mechanical polishing. Background Technology

[0002] Chemical mechanical planarization (CMP) is a variation of polishing processes widely used to planarize or flatten the building layers of integrated circuits, or similar structures. In particular, CMP is often used in the fabrication of three-dimensional circuit structures to produce flat, uniform layers of defined thickness through additive stacking and planarization. CMP removes excess deposited material from the surface of a substrate (e.g., a wafer) to produce an extremely flat layer of uniform thickness, where uniformity extends throughout the entire substrate (e.g., wafer) region. When uniform thickness extends throughout the entire wafer, it is referred to as global uniformity.

[0003] CMP uses a liquid (often called a slurry) that may contain nanoscale particles. The slurry is delivered to the surface of a rotating multilayer polymer pad (sometimes called a polishing disc), which is mounted on a rotating pressure plate. The polishing pad includes a polishing layer and may include a subpad. A substrate (e.g., a wafer) is mounted in a separate jig or holder with a separate rotation mechanism and pressed against the surface of the pad under a controlled load. This can cause a high relative velocity of motion between the substrate (e.g., the wafer) and the polishing pad, resulting in high shear rates or abrasion at both the substrate and pad surfaces. This shearing and trapping of slurry particles at the pad / substrate junction abrades the substrate (e.g., the wafer) surface, thereby removing material from the substrate surface. Controlling the removal rate and the uniformity of removal is important.

[0004] Polishing pads contain polymer materials that can be porous. Therefore, polishing pads are typically heat-insulating. Furthermore, the compressibility of the polishing pad can cause polishing performance to vary across the entire diameter of the pad. Summary of the Invention

[0005] This document discloses a polishing pad for chemical mechanical polishing, comprising a polishing layer and a sub-pad. The polishing layer has a polishing surface and a polishing layer interface surface opposite to the polishing surface, and the polishing layer contains a polishing material. The sub-pad layer has a sub-pad interface surface adjacent to the polishing layer interface surface and a bottom surface opposite to the sub-pad interface surface, and the sub-pad layer contains a sub-pad material. The sub-pad layer has an average compressive modulus of 1 to 5 MPa at pressures of 24 to less than 48 kPa and an average compressive modulus of 5 to 20 MPa at pressures of 48 to 76 kPa, and a true strain of less than or equal to 10% at compressive pressures up to 1.2 MPa. Attached Figure Description

[0006] Referring now to the accompanying drawings, which are exemplary embodiments, and wherein the same element numbers are the same.

[0007] Figure 1 This is a top view of the polishing pad example disclosed in this article.

[0008] Figure 2 Is passing through like Figure 1 The cross-sectional view of the thickness of the polishing pad at a-a' shows an embodiment of the polishing pad as disclosed herein.

[0009] Figure 3 Is passing through like Figure 1 The cross-sectional view of the thickness of the polishing pad at a-a' shows a second embodiment of the polishing pad as disclosed herein.

[0010] Figure 4 This is a graph showing the true stress versus the true strain of the sample pad, as shown in Example 1. Detailed Implementation

[0011] like Figures 1-3 As shown, pad 1 has a polishing layer 10 and a sub-pad 20. The polishing layer has a top polishing surface 12, a polishing layer interface surface 16, and a thickness t. Optional recesses 14 can be found in the polishing layer 10, these recesses... Figure 1 The recess 14 is shown as a concentric groove, but other recess shapes can be used, such as radial grooves extending from the center of the pad, cross-hatched grooves, or combinations thereof. The presence of the recess is preferred. The recess 14 has a depth d. For a new pad, the depth d can be at least 80%, at least 90%, at least 95%, at least 98% of the thickness t, such as... Figure 2 As shown. With Figure 2 If the polished layer 10 wears down from top to bottom during polishing and diamond dressing, this percentage decreases. Optionally, for higher heat flux, the thickness t can be 100% of the thickness t, such as Figure 3 As shown. With Figure 3 If the polished layer 10 is worn down from top to bottom, then this percentage remains constant at 100% of the thickness.

[0012] Sub-pad 20 has a sub-pad interface surface 26 and a sub-pad bottom surface 22. Pressure-sensitive or hot-melt adhesive (not shown) can be used to combine the sub-pad with the polishing layer. Polishing pad 1 may include an optional endpoint detection window 100.

[0013] The thickness t of the polishing layer can be, for example, from 0.5 or 1 mm up to 4, up to 3, or up to 2 mm. The thickness of the sub-shield layer can be, for example, from 0.5 or 1 mm up to 4, up to 3, up to 2, or up to 1.5 mm.

[0014] The thickness of the top pad material at the bottom of the recess can be less than 0.5, 0.4, 0.3, 0.2, or 0.1 mm, or all the top pad material in the recess can be removed to expose the underlying layer, such as the sub-pad.

[0015] Polishing layer 10 may comprise a polymer. Polishing layer 10 may be porous. Porosity may be provided, for example, by adding hollow flexible polymer elements (e.g., hollow microspheres), foaming agents, blowing agents, or supercritical carbon dioxide. Examples of polymeric materials used for the polishing layer include: polyurethane, polycarbonate, polysulfone, nylon, polyether, polyester, polystyrene, acrylic polymers, polymethyl methacrylate, polyvinyl chloride, polyvinyl fluoride, polyethylene, polypropylene, polybutadiene, polyethyleneimine, polyethersulfone, polyamide, polyetherimide, polyketone, epoxy resin, silicone, copolymers thereof (such as polyether-polyester copolymers), and combinations or blends thereof. The polishing layer may comprise a polymer, which is a polyurethane formed by the reaction of one or more polyfunctional isocyanates and one or more polyols. For example, polyisocyanate-terminated urethane prepolymers may be used. The polyfunctional isocyanate used to form the polishing layer of the chemical mechanical polishing pad of the present invention may be selected from the group consisting of: aliphatic polyfunctional isocyanates, aromatic polyfunctional isocyanates, and mixtures thereof. For example, the polyfunctional isocyanate used to form the polishing layer of the chemical mechanical polishing pad of the present invention can be a diisocyanate selected from the group consisting of: 2,4-toluene diisocyanate; 2,6-toluene diisocyanate; 4,4'-diphenylmethane diisocyanate; naphthalene-1,5-diisocyanate; bitoluidine diisocyanate; p-phenylene diisocyanate; phenyl diisocyanate; isophorone diisocyanate; hexamethylene diisocyanate; 4,4'-dicyclohexylmethane diisocyanate; cyclohexane diisocyanate; and mixtures thereof. The polyfunctional isocyanate can be an isocyanate-terminated urethane prepolymer formed by reacting a diisocyanate with a prepolymer polyol. The isocyanate-terminated urethane prepolymer can have 2 to 12 wt.%, 2 to 10 wt.%, 4 to 8 wt.%, or 5 to 7 wt.% unreacted isocyanate (NCO) groups. The prepolymer polyol used to form polyfunctional isocyanate-terminated urethane prepolymers can be selected from the group consisting of: diols, polyols, polyol diols, copolymers thereof, and mixtures thereof. For example, the prepolymer polyol can be selected from the group consisting of: polyether polyols (e.g., poly(oxytetramethylene) glycol, poly(oxypropylene) glycol, and mixtures thereof); polycarbonate polyols; polyester polyols; polycaprolactone polyols; mixtures thereof; and mixtures thereof with one or more low molecular weight polyols selected from the group consisting of: ethylene glycol; 1,2-propanediol; 1,3-propanediol; 1,2-butanediol; 1,3-butanediol; 2-methyl-1,3-propanediol; 1,4-butanediol; neopentyl glycol; 1,5-pentanediol; 3-methyl-1,5-pentanediol; 1,6-hexanediol; diethylene glycol; dipropylene glycol; and tripropylene glycol.For example, the prepolymer polyol may be selected from the group consisting of: polytetramethylene ether glycol (PTMEG); ester-based polyols (such as ethylene glycol adipate, butylene adipate); polypropylene ether glycol (PPG); polycaprolactone polyol; copolymers thereof; and mixtures thereof. For example, the prepolymer polyol may be selected from the group consisting of: PTMEG and PPG. When the prepolymer polyol is PTMEG, the concentration of unreacted isocyanate (NCO) in the isocyanate-terminated urethane prepolymer may be 2 to 10 wt.% (more preferably 4 to 8 wt.%; most preferably 6 to 7 wt.%). Examples of commercially available PTMEG-based isocyanate-terminated urethane prepolymers include... Prepolymers (available from COIM USA, Inc., such as PET-80A, PET-85A, PET-90A, PET-93A, PET-95A, PET-60D, PET-70D, PET-75D); Prepolymers (available from Chemtura, such as LF 800A, LF 900A, LF 910A, LF930A, LF 931A, LF 939A, LF 950A, LF 952A, LF 600D, LF 601D, LF 650D, LF 667, LF 700D, LF750D, LF751D, LF752D, LF753D and L325); Prepolymers (available from Anderson Development Company, such as 70APLF, 80APLF, 85APLF, 90APLF, 95APLF, 60DPLF, 70APLF, 75APLF). When the prepolymer polyol is PPG, the concentration of unreacted isocyanate (NCO) in the isocyanate-terminated urethane prepolymer can be 3 to 9 wt.% (more preferably 4 to 8 wt.%; most preferably 5 to 6 wt.%). Examples of commercially available PPG-based isocyanate-terminated urethane prepolymers include... Prepolymers (available from US-based CO.E. Inc., such as PPT-80A, PPT-90A, PPT-95A, PPT-65D, and PPT-75D); Prepolymers (available from Chrysler, such as LFG 963A, LFG 964A, LFG 740D); and Prepolymers (available from Anderson Development, such as 8000APLF, 9500APLF, 6500DPLF, 7501DPLF). Isocyanate-terminated urethane prepolymers can be low-free, isocyanate-terminated urethane prepolymers with a free toluene diisocyanate (TDI) monomer content of less than 0.1 wt.%. Non-TDI-based isocyanate-terminated urethane prepolymers can also be used. For example, isocyanate-terminated urethane prepolymers include those formed by reacting 4,4'-diphenylmethane diisocyanate (MDI) with a polyol such as polytetramethylene glycol (PTMEG) and optionally a diol such as 1,4-butanediol (BDO). When using such isocyanate-terminated urethane prepolymers, the concentration of unreacted isocyanate (NCO) is preferably 4 to 10 wt.% (more preferably 4 to 10 wt.%, most preferably 5 to 10 wt.%). Examples of commercially available isocyanate-terminated urethane prepolymers in this category include: Prepolymers (available from US-based CO.E., such as 27-85A, 27-90A, 27-95A); Prepolymers (available from Anderson Development Corporation, such as IE75AP, IE80AP, IE 85AP, IE90AP, IE95AP, IE98AP); and Prepolymers (available from Kerturia, such as B625, B635, B821).

[0016] Sub-pad 20 is non-porous. Sub-pad 20 has an average elastic modulus of 1 to less than 5 MPa at compressive pressures up to 48 kPa (e.g., pressures from 24 to 48 kPa) and an average compressive elastic modulus of 5 to 20 MPa at compressive pressures from 48 to 76 kPa. For the purposes of this specification, the average elastic modulus (or compressive modulus in the elastic region) represents the average value as measured from the low to the high of the compressive pressure range. The sub-pad can have a true strain of less than or equal to 10% at compressive pressures up to 1.2 MPa. This compressibility profile enables profile adjustability, such as adjusting edge effects. Specifically, the sub-pad can have sufficient compressibility to improve global polishing uniformity while limiting excessive sub-pad deformation to simultaneously promote a more uniform edge profile for improved semiconductor wafer yield. Another advantage of this sub-pad is that it can maintain mechanical stability across multiple wafers without the problem of polishing fluid wicking into the sub-pad. These modulus and strain values ​​are measured using the following procedure: Indentation testing can be performed on an MTS-Criterion 43 electromechanical testing system equipped with a 1 kN load cell and a compression plate. The top plate can be replaced with a stainless steel indenter with a radius of approximately 10 mm at the center and a capacitive sensor surrounding the indenter for displacement measurement between the plates. The sample size can be a die-cut circle with a 2-inch radius, having the sample thickness. The indenter moves downwards at a fixed crosshead speed until the load reaches the specified force value, and then returns to its original position at the same speed. The resulting force versus displacement curve is converted to a true stress versus true strain curve, and then used to calculate the secant modulus value using the load curve.

[0017] The sub-pad may optionally comprise particulate filler in a polymer matrix material. The particulate filler may be thermally conductive, allowing the sub-pad to have a thermal conductivity greater than 1, at least 2, or at least 3 W / m Kelvin (W / mK) and potentially up to 20 or 10 W / mK. Advantageously, the thermal conductivity is 1 to 35 W / mK. More advantageously, the thermal conductivity is 2 to 20 W / mK. Most advantageously, the thermal conductivity is 2 to 10 W / mK.

[0018] Thermal conductivity is measured using a device such as a thermal interface material tester or by measuring the thermal resistance and thermal conductivity of thin materials in accordance with ASTM D5470. For example, a thermal interface material tester from Analysis Tech can be used. For instance, five samples of 1-inch (2.54 cm) diameter pad material are stacked sequentially between a hot and a cold surface, with a load initially applied at room temperature and allowed to reach equilibrium to determine the heat flux. Samples are then loaded sequentially on top of each other, with silicone oil applied between them to limit interfacial effects. The thermal conductivity can then be determined from the slope of a graph of heat flux versus thickness.

[0019] The thermal conductivity of the sub-pad can be uniform from edge to edge. The thermal conductivity of the sub-pad can be uniform throughout its thickness, or it can vary with thickness. The sub-pad layer is non-porous. The composition of the sub-pad can be uniform throughout. For example, the sub-pad can have a monolithic structure.

[0020] The particles are preferably non-conductive. The particles can be inorganic. The particles can be layered (i.e., having a plate-like shape, having multiple layers of inorganic material, or both). Examples of layered particles include boron nitride particles and graphite. Specific examples of thermally conductive particles can be, for example, alumina, boron nitride, aluminum nitride, magnesium oxide, and zinc oxide. Boron nitride particles are preferred. The particles (e.g., boron nitride particles) can have, for example, a particle size of up to 30 micrometers, such as 1 to 20 micrometers or 1 to 15 micrometers as observed by scanning electron microscopy. The amount of particles (e.g., boron nitride) can be based on the total weight of the thermally conductive polymer and the polymer matrix material, ranging from 40, 50, or 60 up to 90, 85, or 75% by weight.

[0021] The polymer matrix material may comprise a first material and a second material. The first material is selected from one or more of vinyl silicone resin, polyisobutylene polymer, silicone rubber, polyurethane, methyl methacrylate, organopolysiloxane, acrylate, and polyamide resin, preferably silicone rubber. The second material is selected from petroleum-based resin, silicone resin (such as MQ silicone resin), polyol, ethyl acrylate, rosin, and vinylphenyl acetate resin, preferably silicone resin. When the polymer matrix comprises, for example, silicone rubber and silicone resin, the polymer matrix may comprise, for example, 2 to 80, preferably 15 to 35, weight percent of silicone resin and 20 to 98, preferably 65 to 85, weight percent of silicone rubber based on the total weight of the polymer matrix.

[0022] Alternatively, a support structure, such as a thin film or nonwoven fabric, can be used. A combination of thermally conductive particles and a polymer matrix can be applied to or impregnated into the support structure. When using a support, the support can have a thickness, for example, from 5 or 10 up to 40 or up to 30 micrometers. When using a support, the thermal conductivity can be varied by the thickness of the sub-pad.

[0023] Polishing pads disclosed herein can provide desired polishing characteristics (e.g., one or more of the following: desired removal rate, polishing consistency across the entire pad diameter, low defects, and polishing consistency when used to polish a series of substrates). For example, embodiments in which the polishing pad includes a thermally conductive sub-pad and grooves in the main pad can provide pads with relatively low thermal resistance and good thermal conductivity. These pads can facilitate thermal management at the polished surface. For example, using polishing pads as disclosed herein, the polished surface can be heated and cooled more slowly during conventional polishing, which can provide a more stable temperature distribution at the polished surface during polishing. When using heated or cooled pressure plates (e.g., water-heated or water-cooled pressure plates), the polished surface can be heated or cooled more quickly. In summary, when using temperature-controlled devices (e.g., temperature-controlled pressure plates), the pads of the present invention can optionally facilitate heat transfer through the pads. This can result in a more consistent removal rate. Furthermore, the thermal conductivity of the sub-pads can enhance the effectiveness of the thermal control system built into the pressure plates of the polishing apparatus by facilitating heat transfer through the pads.

[0024] The polishing pads disclosed herein can be manufactured, for example, by first forming a polishing layer. A sub-pad layer is then applied to the polishing layer. For example, an adhesive can be used to adhere the sub-pad layer to the polishing layer interface surface. Alternatively, a sub-pad precursor composition comprising a thermally conductive polymer in a precursor of a matrix material can be applied to the polishing layer interface surface and then cured. Grooving of the polishing layer typically occurs after the formation of the polishing layer / sub-pad stack, and should occur after the formation of the polishing layer / sub-pad stack when the grooves extend to 100% of the polishing layer thickness. Example Example 1

[0025] The modulus and strain of various pad materials under compression were evaluated using the procedures described herein. A control pad material is porous polyurethane on a nonwoven support used in some commercial polishing pads. Other pad materials useful in the pads disclosed herein are materials of various thicknesses containing boron nitride in a silicone matrix on a nonwoven substrate. The pad materials used in the pads of this invention exhibit significantly different strain behaviors, such as… Figure 4 As shown in Table 1, the modulus of the samples is as follows. Table 1 Example 2

[0026] The polishing performance of pads with both radial and concentric groove patterns was tested. The results are shown in Table 2. Table 2 Example 3

[0027] Various combinations of sub-pad compositions and master pad (polished layer) thicknesses were evaluated to determine the thermal resistance through the pad. In each case shown in Table 1, the sub-pad thickness was 50 mils (1.27 mm), consisting of 20 and 30 mil (0.51 and 0.76 mm) layers bonded together with adhesive, and the master pad was based on a porous polyurethane material. The composition of the sub-pad (and therefore its thermal conductivity) and the thickness of the master pad (polished layer) were varied. Samples 1A-1D and 2A-2D, with sub-pad materials of low thermal conductivity, exhibited high thermal resistance regardless of the master pad thickness. When the thermal conductivity of the sub-pad material was high, as in samples 3A-3D, 4A-4D, and 4A-4D, the thickness of the master pad affected the thermal resistance of the pad structure. This indicates that, to achieve the desired heat transfer characteristics in the pad, a combination of a relatively high thermal conductivity sub-pad material and a recess extending into or near the recess of the sub-pad material can provide good thermal management capabilities within the pad. It is noteworthy that with a primary pad thickness of approximately 1 mm or greater, the thermal resistance of the secondary pads in the range of 5–34 W / mK shows almost no difference. A similar trend was observed for a secondary pad thickness of 20 mils (0.508 mm). Table 3 Example 4

[0028] Polishing pads are prepared by attaching the sub-pad to the polishing layer using a double-sided pressure-sensitive adhesive. The control pad is a commercially available pad with a porous polyurethane sub-pad on a nonwoven support. The thermal conductivity of this sub-pad is approximately 0.02 W / mK. Pads F and G of the present invention use a non-porous sub-pad containing boron nitride on a nonwoven support, which has a thermal conductivity of approximately 5 W / mK. The groove pattern is consistent throughout the samples; however, the grooves on pad F of the present invention do not expose the underlying sub-pad, while the grooves on pad G of the present invention expose the underlying sub-pad.

[0029] The pad was placed on a pressure plate, brought into contact with the wafer, and rotated. Hot water (approximately 50°C) was applied to the surface of the pad for 3 minutes, followed by room temperature water for 3 minutes. The surface temperature was monitored using an IR gun. Data showed that when hot water was applied, the temperature of the polished layer surface of the control pad increased faster and reached a higher value compared to the pads F and G of the present invention. However, when room temperature water was applied, the control pad cooled faster and to a lower level than the pads F and G of the present invention. This demonstrates that the pad of the present invention can effectively mitigate temperature fluctuations during polishing. Similarly, when hot water was applied, the temperature of the polished layer surface of the pad F, which has grooves that do not expose the sub-pad, increased faster and reached a higher value compared to the pad G of the present invention, where the grooves extend to the sub-pad layer, and when room temperature water was applied, the pad F of the present invention cooled faster and to a lower level than the pad G of the present invention. Example 5

[0030] The pads of the present invention, each polishing a series of wafers, were tested and compared with a control pad having a polyurethane porous sub-pad (with a thermal conductivity of 0.02 W / mK) impregnated on a nonwoven fabric and a sub-pad having boron nitride in a silicone matrix composition (with a thermal conductivity of 5 W / mK). A pressure-sensitive adhesive combined the sub-pad with the polishing layer. The pads of the present invention showed a significant increase in removal rate with increasing number of wafers, while the control pad showed a smaller change. This is consistent with temperature data, as the control pad quickly reached equilibrium and was substantially stable, while the pads of the present invention required several wafers to reach temperature stability. This indicates that polishing performance can be affected by varying the temperature of the pads as disclosed herein.

[0031] This disclosure further covers the following aspects.

[0032] Aspect 1: A polishing pad for chemical mechanical polishing, the polishing pad comprising: a polishing layer having a polishing surface and a polishing layer interface surface opposite to the polishing surface, the polishing layer containing a polishing material; a sub-pad layer having a sub-pad interface surface adjacent to the polishing layer interface surface and a bottom surface opposite to the sub-pad interface surface, the sub-pad layer containing a sub-pad material; herein, the sub-pad layer has an average compressive modulus of 1 to 5 MPa at a pressure of 24 to less than 48 kPa and an average compressive modulus of 5 to 20 MPa at a pressure of 48 to 76 kPa, and a true strain of less than or equal to 10% at a compressive pressure up to 1.2 MPa.

[0033] Aspect 2: The polishing pad as described in aspect 1, wherein the sub-pad layer is non-porous.

[0034] Aspect 3: The polishing pad as described in aspect 1 or 2, wherein the pad material comprises particulate filler in a polymer matrix material.

[0035] Aspect 4: The polishing pad as claimed in claim 3, wherein the particulate filler is an inorganic material.

[0036] Aspect 5: The polishing pad as claimed in claim 3, wherein the particulate filler is a thermally conductive material.

[0037] Aspect 6: The polishing pad of claim 3, wherein the particulate filler is present in an amount of 40 to 90, preferably 45 to 85, more preferably 50 to 80 by weight percentage based on the total weight of the particulate filler and the polymer matrix material.

[0038] Aspect 7: The polishing pad as described in any one of Aspects 3-6, wherein the polymer matrix material comprises a silicone composition.

[0039] Aspect 8: The polishing pad as described in aspect 7, wherein the silicone composition comprises 2 to 80 weight percent of silicone binder and 20 to 98 weight percent of silicone rubber based on the total weight of the silicone composition.

[0040] Aspect 9: The polishing pad as described in any one of Aspects 3-8, wherein the secondary pad material is disposed on a woven or nonwoven material support.

[0041] Aspect 10: The polishing pad as described in any one of Aspects 3-9, wherein the particulate filler is boron nitride.

[0042] Aspect 11: The polishing pad as described in any of the preceding aspects, wherein the pad material has a thermal conductivity of at least 1, preferably 1 to 35, more preferably 2 to 20, and even more preferably 2 to 10 W / mK.

[0043] Aspect 12: The polishing pad as described in any of the preceding aspects, wherein the polishing layer has a recess extending to a depth of at least 80%, preferably at least 90%, more preferably 100% of the thickness of the polishing layer.

[0044] All ranges disclosed herein include endpoints, and endpoints can be combined independently of each other (e.g., the range “up to 25 wt.%, or more specifically 5 wt.% to 20 wt.%” includes the endpoints and all intermediate values ​​within the range “5 wt.% to 25 wt.%”, etc.). Furthermore, the upper and lower limits can be combined to form ranges (e.g., “at least 1 or at least 2 weight percent” and “up to 10 or 5 weight percent” can be combined to form ranges “1 to 10 weight percent”, or “1 to 5 weight percent”, or “2 to 10 weight percent”, or “2 to 5 weight percent”).

[0045] This disclosure may alternatively include any suitable components disclosed herein, consist of any suitable components disclosed herein, or consist substantially of any suitable components disclosed herein. This disclosure may also be formulated to be free of, or substantially free of, any components, materials, ingredients, additives, or substances used in prior art compositions or otherwise not essential for achieving the function or objective of this disclosure.

[0046] All cited patents, patent applications and other references are incorporated herein by reference in their entirety. However, if any terminology in this application contradicts or conflicts with a terminology in an incorporated reference, the terminology from this application shall take precedence over the conflicting terminology from the incorporated reference.

[0047] Unless otherwise stated herein, all test standards are valid up to the filing date of this application or, if priority is claimed, the most recent standard valid up to the filing date of the earliest priority application in which the test standard appears.

Claims

1. A polishing pad for chemical mechanical polishing, the polishing pad comprising: A polishing layer having a polishing surface and a polishing layer interface surface opposite to the polishing surface, the polishing layer comprising a polishing material. A secondary pad layer, the secondary pad layer having a secondary pad interface surface adjacent to the interface surface of the polishing layer and a bottom surface opposite to the secondary pad interface surface, the secondary pad layer comprising a secondary pad material. The sub-shield layer has an average compressive modulus of 1 to 5 MPa under a pressure of 24 to less than 48 kPa and an average compressive modulus of 5 to 20 MPa under a pressure of 48 to 76 kPa, and a true strain of less than or equal to 10% under a compressive pressure of up to 1.2 MPa.

2. The polishing pad as described in claim 1, wherein, The sub-shield layer is non-porous.

3. The polishing pad as described in claim 2, wherein, The sub-layer comprises particulate fillers in a polymer matrix material.

4. The polishing pad as described in claim 3, wherein, The granular filler is an inorganic material.

5. The polishing pad as described in claim 3, wherein, The granular filler is a thermally conductive material.

6. The polishing pad as described in claim 3, wherein, The particulate filler is present in an amount of 40 to 90% by weight based on the total weight of the particulate filler and the polymer matrix material.

7. The polishing pad as described in claim 3, wherein, The polymer matrix material comprises a silicone composition.

8. The polishing pad as claimed in claim 7, wherein, The silicone composition comprises 2 to 80 weight percent of silicone adhesive and 20 to 98 weight percent of silicone rubber based on the total weight of the silicone composition.

9. The polishing pad as claimed in claim 3, wherein, The secondary pad material is placed on a woven or nonwoven material support.

10. The polishing pad as claimed in claim 5, wherein, The particulate filler is boron nitride.

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