Composite pads for chemical mechanical polishing

Abstract

A chemical mechanical polishing pad comprises a substantially non-porous polishing layer including an aggregate comprising a polymer matrix and polymer particles embedded in the polymer matrix, wherein the polymer particles are present in an amount of 5 to 35 weight percent based on the weight of the polishing layer, the aggregates have a size greater than 1 μm, and the polymer particles have a tensile modulus higher than that of the polymer matrix. The polishing layer is viscoelastic and has a tensile modulus greater than 1000 Pa. ‑1 GEL. Polishing metal / insulator composites with this type of pad can result in minor dish-shaped indentations in the metal features.

Description

Technical Field

[0001] The field of this invention is chemical mechanical polishing and pads that can be used for chemical mechanical polishing. Background Technology

[0002] Chemical mechanical planarization (also known as chemical mechanical polishing or CMP) is a polishing process widely used in the manufacturing of integrated circuits to planarize or flatten layers. The purpose of CMP is to remove excess material from the surface of a substrate (e.g., a silicon wafer with various electroactive and electrodielectric layers) to produce an extremely flat layer of uniform thickness, with this uniformity extending throughout the entire wafer area. Controlling the removal rate and removal uniformity is crucial.

[0003] CMP uses a liquid (often called a slurry) that can contain nanoscale particles. The slurry can be fed onto the surface of a rotary chemical mechanical polishing pad mounted on a rotating pressure plate. The substrate to be polished or planarized 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 results in a high-rate relative motion between the substrate and the polishing pad, abrading the substrate surface, thereby causing material removal and planarization.

[0004] To control the flow rate, prevent slippage, and efficiently deliver the slurry beneath the wafer, various types of textures are incorporated into the upper surface of the polishing pad. Fine textures (microtextures) can be created by trimming (i.e., grinding) the pad with, for example, a fine array of diamonds. These fine textures are essentially random. Larger-scale textures, such as grooves or bumps with various patterns (e.g., intersecting lines, circles, radial lines, etc.) and sizes (also known as macrotextures), can aid in slurry transport and hydrodynamics.

[0005] Pads are typically multilayer polymer-based materials with sub-pad layers and polishing layers. The polishing layer usually contains closed-cell porous material. The pore structure exposed during trimming and wafer polishing provides good microtexture. For non-porous pads, as outlined in U.S. Patent No. 5,489,233, the trimming process is critical because it is the primary source of microtexture formation on contact roughness. For non-porous pads, shearing during use wears away the microtexture, resulting in pad glazing. Therefore, to reduce this loss of microtexture, commercially produced and used non-porous pads typically have both high shear and high elastic modulus.

[0006] While porous pads are effective for polishing dielectric layers used in integrated circuit manufacturing, they are often less ideal for polishing metal / dielectric composite structures, such as those with copper or tungsten interconnects. Specifically, porous pads may have lower rigidity, may suffer from texture collapse, and may cause slurry effluent to become trapped in the pores. In polishing metal / dielectric composite layers, these characteristics can lead to metal dishing or other performance problems, such as reduced removal rates or increased defects.

[0007] In the latter case, the fabrication sequence of the wiring structure involves progressively building a layered structure, which can be essentially as follows: (a) depositing an insulating layer and applying a patterned mask with open areas to the surface of the insulator. (b) then etching the open areas to create recesses or vias in the insulator and removing the mask. (c) depositing metal that fills the etched holes and can cover the entire surface. (d) then polishing the deposited metal layer to remove excess metal (called metal overlay) and expose the filled vias (now conductive plugs). The steps of this process can then be repeated as desired to build a three-dimensionally flat wiring structure. Polishing these composite structures produces two types of undesirable non-flatness (etching and dish-shaped recesses).

[0008] Corrosion refers to the thinning of the insulating material between metallic features (e.g., plugs) in a wiring structure once the metallic covering is removed. This can occur during a continuous polishing process (often referred to as over-polishing).

[0009] Dish-shaped depressions are an increase in the surface morphology of composite structures after the removal of metal overlays. These depressions are associated with excessive removal of metals (such as copper deposited in etched structures); and typically, they continue to increase during over-polishing. One source of dish-shaped depressions is the difference in CMP removal rates between the two (or more) materials in the composite. Because conductive metals typically have higher removal rates, dish-shaped depressions appear as recesses in the final metallic structure. Dish-shaped depressions are a significant source of resistance variations and contact reliability in the final constructed structure.

[0010] As device structures shrink, the requirements for both dish-shaped depressions and defects become increasingly stringent. Summary of the Invention

[0011] This paper discloses a chemical mechanical polishing pad comprising a substantially non-porous polishing layer containing a polymer matrix and polymer particle agglomerates embedded in the polymer matrix. The polymer particles are present in an amount of 5 to 35 weight percent based on the weight of the polishing layer. These agglomerates have a size greater than 1 μm and possess a tensile modulus higher than that of the polymer matrix. The polishing layer is viscoelastic. The polishing layer can have a tensile modulus greater than 1000 Pa. -1 GEL.

[0012] This paper also discloses a method that involves polishing a composite structure in which metallic features are surrounded by an insulating material using a pad as disclosed herein. Attached Figure Description

[0013] Reference is now made to the accompanying drawings, which are exemplary embodiments.

[0014] Figure 1 The image is a micrograph of the polished surface of the pad before finishing, showing polymer particles of the polymer-polymer composite as disclosed herein.

[0015] Figure 2 These are micrographs of a contrast polished layer surface before finishing, without the polymer particles disclosed herein. Detailed Implementation

[0016] The chemical mechanical polishing pads disclosed herein include a polishing layer. The polishing layer is substantially non-porous or non-porous. As used herein, "substantially non-porous" means that the polishing layer contains less than 5, less than 1, less than 0.5, or less than 0.1% by volume of void space. As used herein, "non-porous" means that no voids have been intentionally introduced into the polishing layer, while recognizing that some random voids as unintentional artifacts may occur during the formation of the polishing pad. However, the polishing layer may be non-porous.

[0017] The polishing layer contains a polymer matrix with aggregates of polymer particles dispersed therein.

[0018] The polymer matrix has a tensile modulus. According to ASTM D412-16, at 23°C, the tensile modulus of the polymer matrix can range from 50 to 200, 150, or 120 MPa. According to ASTM-5279-21, the polymer matrix can have a tangent δ (tanδ) of 0.13 to 0.3 over a temperature range from 20°C to 40°C. The polymer matrix can have a Shore D hardness of 25 to 70, 30 to 60, or 35 to 50, as measured according to ASTM D2240-15.

[0019] The polymer matrix can contain a variety of polymer materials, such as polyurethane, polybutadiene, polyethylene, polystyrene, polypropylene, polyester, polyacrylamide, polyvinyl alcohol, polyvinyl chloride polysulfone, and polycarbonate. The polymer matrix can contain polyurethane. The polymer matrix can contain thermoplastic polyurethane. For the purposes of this specification, "polyurethane" is a product derived from difunctional or polyfunctional isocyanates, such as polyether urea, polyisocyanurate, polyurethane, polyurea, polyurethane urea, copolymers thereof, and mixtures thereof.

[0020] The polyfunctional isocyanate used in the polishing layer of the chemical mechanical polishing pad of the present invention can be selected from the group consisting of: aliphatic polyfunctional isocyanates, aromatic polyfunctional isocyanates, and mixtures thereof. The polyfunctional isocyanate used in the polishing layer of the chemical mechanical polishing pad of the present invention can, for example, be selected from the group consisting of: 2,4-toluene diisocyanate; 4,4'-diphenylmethane diisocyanate; naphthalene-1,5-diisocyanate; isophorone diisocyanate; hexamethylene diisocyanate; 4,4'-dicyclohexylmethane diisocyanate; or mixtures thereof.

[0021] Polyols (e.g., diols) that can react with isocyanate functional groups can be polyethers (e.g., HO-(RO)). n -H, where R is an alkyl group having 2, 3, 4 or 5 carbon atoms, and n is the desired number of repeating units to provide a desired weight-average molecular weight, such as 250-3000 g / mol, for example, like polyethylene glycol, polypropylene glycol or polytetramethylene ether glycol) or polyester (e.g., HO-(ORC(=O))). n -L-(C(=O)-RO) n -H, where R is an alkyl group having 2, 3, 4 or 5 carbon atoms, n is the desired number of repeating units to provide a desired weight-average molecular weight, such as 250-3000 g / mol, and L is a linking group such as an ether (e.g., -ORO- or -ORORO-, where R is an alkyl group having 1, 2, 3 or 4 carbon atoms)).

[0022] Thermoplastic polyurethanes contain hard and soft segments formed by the reaction of diisocyanates with short-chain diols and diisocyanates with long-chain diols.

[0023] The polished layer comprises polymer particles that are agglomerates within a polymer matrix. These polymer particles have a tensile modulus higher than the tensile strength of the polymer matrix. At 20°C, the tensile modulus of the polymer used in the polymer particles can be greater than 400, or greater than 500, up to 2000, 1500, or 1000 MPa. Measuring the tensile modulus directly on the polymer particles can be challenging. Therefore, the tensile modulus can be roughly estimated from a bulk polymer having a composition similar to that of these particles. The tensile modulus of this bulk polymer can be measured as per ASTM D412-16, or it can be derived from data published by the supplier for such bulk polymers. Directly measuring the hardness of the polymer particles can also be challenging, but it can also be roughly estimated from a bulk polymer having a composition similar to that of these particles, according to ASTM D2240 (2015), or from data published by the supplier for such bulk polymers. For example, the hardness of the bulk polymer of the polymer particles can be at least 50, or at least 55, up to 100, or 75.

[0024] Polymer particles form agglomerates within a polymer matrix. For the purposes of this specification, an agglomerate is a cluster of three or more particles, wherein the spacing between adjacent particles is less than the particle size. These agglomerates unexpectedly improve planarization efficiency. As determined by scanning electron microscopy (SEM), agglomerates can have a size of 1 to 100 μm, preferably 2 to 70 μm. More agglomerates may be located in the smaller portion of this size range, while a small portion (tail) of some agglomerates may be located in the larger range. For example, the majority (e.g., at least 80% or at least 90%) of the agglomerates may be less than 10 μm or less than 5 μm, and a minority (e.g., less than 20% or less than 10%) of the agglomerates may be greater than 10 μm. Very few (e.g., less than 5% or less than 3%) of the agglomerates may be greater than 20 μm. Agglomerates may be single particles or agglomerates of more than one particle. Polymer particles may have a size of 1 to 20 or 2 to 10 μm. Particle size can be the nominal particle size as specified by the supplier. Alternatively, particle size can be determined by a particle size analyzer such as the Mastersizer from Malvern Panalytical. TM To measure.

[0025] The amount of polymer particles in the polishing layer can be 5 to 35 or 8 to 25% of the total weight of the polishing layer.

[0026] Examples of polymer particles include fluoropolymers, polylactic acid, polycarbonate, or polyurethane having a modulus higher than that of the polymer matrix. Preferably, the polymer particles are fluoropolymers. Fluorinated polymer particles (PTFE, PFA) exhibit improved defect and polishing removal rates when used as powder in commercial pad formulations, particularly when polishing semiconductor substrates with cationic abrasives. Acceptable fluorinated additives have the following chemical structures: (a) PTFE (polytetrafluoroethylene); (b) PFA (a copolymer of tetrafluoroethylene (TFE) and perfluoroalkyl vinyl ether (PFAVE); (c) FEP (a copolymer of tetrafluoroethylene (TFE) and hexafluoropropylene (HFP)); or (d) PVF (polyvinylidene fluoride). Further acceptable examples of fluoropolymers are ETFE (ethylene tetrafluoroethylene), PVDF (polyvinylidene fluoride), and ECTFE (ethylene trifluorochloroethylene). Preferably, the fluoropolymer is selected from PTFE, PFA, FEP, PVF, ETFE, ECTFE, and combinations thereof.

[0027] The polishing layer of the chemical mechanical polishing pad of the present invention may optionally further contain a variety of micro-elements, such as abrasive grains, water-soluble materials, and / or insoluble phase materials (e.g., mineral oil). The polishing layer may be free of such additives. Such additives may be present in an amount up to about 25, up to about 20, up to about 15, or up to about 10% by weight based on the total weight of the polishing layer. When present, such additives may be present in an amount of at least 0.1 or 1% by weight based on the total weight of the polishing layer. The polishing layer may be free of trapped air bubbles, hollow polymer materials, and liquid-filled hollow polymer materials. The polishing pad may be free of additional solid micro-elements.

[0028] The polishing layer of the chemical mechanical polishing pad of the present invention can exhibit a Shore D hardness of 25 to 70, 30 to 60, or 35 to 50 as measured according to ASTM D2240 (2015). The hardness of the polishing layer can be measured directly on the polishing layer, regardless of whether the polishing layer includes pores.

[0029] As measured by ASTM D7264 / D7264M-21(2021) "Standard Test Method for Flexural Properties of Polymer Matrix Composite Materials", the polished layer can have, for example, 500 to 1500 or 700 to 1200 N-mm. 2 Flexural rigidity.

[0030] According to ASTM D412-16, at 23°C, the composition of the polished layer (a non-porous solid material) can have a tensile modulus from 50 to 200, 150, or 120 MPa. The composition of the polished layer (non-porous) can have an elastic storage modulus (G') less than 125 MPa (e.g., from 50 to 125 or 100 MPa) at 30°C, as measured according to ASTM 5279-08. According to ASTM-5279-08 (2008), the composition of the polished layer can have a tangent δ (tanδ) of 0.13 to 0.3 over a temperature range from 20°C to 40°C. All modulus numbers (G') were obtained using a 36 mm × 6.5 mm sample with a 20 mm gap between the fixtures on an Ares G2 instrument (supplied by TA Instruments). The instrument setup was as follows:

[0031] Nitrogen atmosphere

[0032] Starting temperature -100℃, inherent setpoint: Off

[0033] Soaking time: 20.0s, waiting temperature: open

[0034] Heating rate: 3.0℃ / min

[0035] Soaking time after heating: 0.0s

[0036] Estimated completion time: 1 hour 23 minutes 0 seconds

[0037] Sampling interval 10s / pt

[0038] Strain % 0.2%

[0039] single point

[0040] Angular frequency 10 rad / s

[0041] Data collection mode: Relevance is selected.

[0042] Delay loop 0.5

[0043] Delay time: 3.0s

[0044] Sampling loop 2 half-cycles

[0045] Correlation-based frequency: Off; Save waveform (dot display): Off; Save image: Off; Iterative strain: Off

[0046] Adjustment: Off. Use additional harmonics: Off.

[0047] Superimposed stable shear rate: Maintain axial force during acquisition: On

[0048] Enable: Disable Enable: Disable Enable: Disable

[0049] The material of the polished layer may have a tensile strength of at least 30, at least 31, at least 31.5 or at least 32 MPa as measured by ASTM D412-16.

[0050] The composition of the polishing layer is viscoelastic. The composition of the polishing layer can have a strength greater than 1000 Pa, as determined by ASTM 5279-08 (“Standard Terminology Relating to Dynamic Mechanical Measurements of Plastics”, which is incorporated herein by reference in its entirety for all useful purposes). -1 For example, from 1000, from 1200, or from 1500 up to 3000 Pa. -1 The "energy loss factor" (GEL) is used. Note that GEL is calculated for polished layers without pores, regardless of whether the polished layer includes pores. GEL is the energy lost per unit volume per deformation cycle. In other words, it is a measure of the area within the stress-strain hysteresis loop. The energy loss factor (GEL) is a function of both tanδ(G″ / G′) at 40°C and the elastic storage modulus (G′), and can be defined by the following equation:

[0051] GEL=tanδ*10 12 / [G′×(1+(tanδ) 2 )]

[0052] Where G′ is in Pascals.

[0053] The polished layer can have an average thickness of 500 to 4000, 700 to 3500, 1000 to 3000, or 1300 to 2500 μm.

[0054] The polishing pads disclosed herein demonstrate a good balance between reduced dishing depressions and good removal rates. These non-porous pads are also less prone to smoothing than other non-porous pads. In situations where constraint is undesirable, the higher gel content of the disclosed pads may help reduce dishing depressions, while the inclusion of particulate aggregates may help prevent smoothing.

[0055] The CMP polishing pad of the present invention may optionally further comprise at least one additional layer bonded to the polishing layer. Preferably, the CMP polishing pad may optionally further comprise a compressible base layer adhered to the polishing layer. The compressible base layer preferably improves the conformability of the polishing layer to the surface of the substrate being polished.

[0056] The CMP polishing pad of the present invention, in its final form, further includes textures of one or more sizes incorporated on its upper surface. These can be categorized as macro-textures or micro-textures based on their size.

[0057] Common types of macrotextures used in CMP control hydrodynamic response and slurry transport, and include, but are not limited to, grooves with various configurations and designs, such as annular, radial, intersecting lines, and protrusions such as pillars. These can be formed as uniform sheets by machining processes or directly onto the pad surface by net-form molding processes. The size of such macrotextures can range from 0.25 to 2 mm. In other words, the distance from the lowest to the highest point of the pad surface can range from 0.25 to 2 mm, or up to 1 mm. However, the pad may also be without macrotexture.

[0058] The polishing pads disclosed herein can have good microtexture and are resistant to polishing. Microtextures contain finer-scale features that generate a large number of surface roughnesses at the points of contact with the substrate wafer where polishing takes place. Common types of microtextures include, but are not limited to, textures formed by grinding with an array of hard particles (such as diamond) (often referred to as pad dressing) before, during, or after use, and microtextures formed during the pad manufacturing process. For example, pads as disclosed herein can have a post-polishing roughness of 100 μm or higher (e.g., 100–120 μm), as determined by confocal microscopy as described in: Z. Liu and T. Buley, Advanced CMP Pad Surface Texture Characterization and Its Impact on Polishing, NCCAVSCMPUG Spring Meeting 2016, Austin, Texas, April 2016.

[0059] The CMP polishing pad of the present invention is adaptable for bonding with the platen of a polishing machine. The CMP polishing pad can be fixed to the platen of the polishing machine, for example, using at least one of pressure-sensitive adhesive and vacuum.

[0060] A key step in substrate polishing operations can be determining the endpoint of the process. Therefore, the pad may include a window that is transparent to light of a selected wavelength. During polishing, a light beam is guided through the window to the substrate surface, where it is reflected and returns through the window to a detector (e.g., a spectrophotometer). Based on the returned signal, characteristics of the substrate surface (e.g., film thickness thereon) can be determined for endpoint detection purposes. To facilitate such light-based endpoint methods, the chemical mechanical polishing pads of the present invention optionally further include an endpoint detection window. Preferably, the endpoint detection window is selected from integrated windows incorporated into the polishing layer and insertable endpoint detection window blocks incorporated into the chemical mechanical polishing pad. For unfilled pads of the present invention with sufficient transmittance, the upper pad layer itself can serve as a window aperture. If the polymer phase of the pads of the present invention exhibits phase separation, transparent regions of the top pad material can also be created by locally increasing the cooling rate during manufacturing to locally suppress phase separation, thereby creating a more transparent region suitable for use as an endpoint window.

[0061] As described in the background section of this invention, CMP polishing pads are used in conjunction with polishing slurries.

[0062] Therefore, this document also discloses a method comprising polishing a composite structure in which metallic features are surrounded by an insulating material using a pad as disclosed herein. These metallic features can comprise any metal, such as those commonly used for interconnects in integrated circuits. The metal may include, for example, tungsten or copper. For instance, a portion of these metallic features may have a size or width on the order of 5 to 100 μm. The polishing yield on such a structure can have dish-shaped recesses less than 100 or less than 90 angstroms.

[0063] Example

[0064] Example 1

[0065] Two sets of polishing pads were prepared by molding using thermoplastic polyurethane as the matrix material or base polymer.

[0066] Contrast pad A is produced using only a base polymer.

[0067] The pad B of the present invention is composited with or contains polytetrafluoroethylene (PTFE) particles (from Zonyl) from The Chemours Company FC, LLC. TM During the incorporation of MP1200 into the molten base polymer, 10% by weight of PTFE particles are added. Based on the similar properties of the PTFE bulk material, the PTFE particles are estimated to have a Shore D hardness of approximately 60 and a tensile modulus of approximately 550 MPa. They have an average particle size of 3 μm (with a narrow size distribution) and a specific surface area of ​​1.5–3 m². 2 / g.

[0068] Comparison pad C uses submicron-sized polylactic acid (PLA) particles instead of PTFE particles. According to published literature and test method ISO 527-2, PLA has an estimated Shore D hardness of 73 and an estimated tensile modulus of 310 to 5620 MPa.

[0069] These pads have a macroscopic structure of cylindrical columns. Both types of pads have the same thickness and sub-pads (SP2310 polyurethane foam sub-pads from DuPont Electronic Materials).

[0070] The polished layer material was characterized for tensile properties according to ASTM D412-16, and for elastic storage modulus (G') and tangent δ according to ASTM 5279-08. GEL was calculated from G' and tangent δ as described above. The hardness of the polished layer was measured according to ASTM D2240 (2015). The flexural stiffness of the polished layer was determined according to ASTM D7264 / D7264M-21 (2021), “Standard Test Method for Flexural Properties of Polymer Matrix Composite Materials”.

[0071] The data are shown in Table 1. For comparison, the properties of certain porous commercial pads with thermoplastic polyurethane matrices are also shown. Note that for these porous pads, the hardness and rigidity modulus were determined for the polished layer including the pores, while the tensile and elastic properties were determined for the matrix polymer composition without pores.

[0072]

[0073] Figure 1 The image shows a 300x magnification photomicrograph of pad B of the present invention, where the light-colored areas are agglomerates of PTFE particles. Pad A, without filler, is shown in the image. Figure 2 No large differences in brightness were observed associated with visible aggregates. Aggregates in the micrometer size range were also not observed in pad C.

[0074] Example 2

[0075] Comparison pad A, the pad of the present invention B, and comparison pad C were used to polish blanket-type 300 mm tungsten wafers to evaluate differences in removal rates, and the surface roughness of the finished pads was determined using confocal microscopy as described herein. The same process was used for all pads. Commercially available tungsten paste was used. The results are summarized in Table 2.

[0076] Pad B (the pad of the present invention) exhibits a significantly higher polishing rate and significantly more finished pad surface texture. Non-composite pad A exhibits lower post-polish roughness, which is not improved by using a more powerful pad dresser with larger diamonds. Conversely, pad B of the present invention exhibits pad roughness that can be varied by changing the dresser. Compared to control pad A without any polymer particle additives, pad C, which does not have agglomerate size, has similar roughness but a worse removal rate.

[0077] Table 2

[0078]

[0079] Example 3

[0080] Patterned tungsten test wafers were also polished and inspected to evaluate the effect of adding a second polymer on dish-shaped depressions. Of particular interest were the results for via arrays with different tungsten via diameters and spacings. Both wafers were polished to an endpoint with an additional 20% over-polishing time. As shown in Table 3, significant differences in via dish-shaped depressions were observed. In the case of contrast pad A, the dish-shaped depression value decreased directly as the via diameter decreased. Conversely, pad B of the present invention exhibited a low and substantially constant level of dish-shaped depressions across the examined via diameter range. The explanation for these results is that the improvement is due to the combination of improved stiffness in pad B resulting from the addition of a second, higher-modulus polymer, and the desired high GEL value. This lack of characteristic dimensional response is highly desirable in device fabrication, as a wide range of via sizes may exist in practical circuits. The lack of variation in dish-shaped depressions significantly improves the ability to produce a uniform electrical response when fabricating multilayer devices.

[0081] Table 3

[0082]

[0083] This disclosure further covers the following aspects.

[0084] Aspect 1: A chemical mechanical polishing pad comprising a substantially non-porous, preferably non-porous, polishing layer comprising a polymer matrix and aggregates of polymer particles embedded in the polymer matrix, wherein the polymer particles are present in an amount of 5 to 35, preferably 8 to 25, by weight based on the weight of the polishing layer, the aggregates having a size greater than 1 μm, the polymer particles having a tensile modulus higher than that of the polymer matrix, and the polishing layer being characterized as viscoelastic and having a Pa greater than 1000, preferably 1500 to 3000. -1 GEL.

[0085] Aspect 2. The chemical mechanical polishing pad as described in aspect 1, wherein a small portion of the agglomerates comprises aggregates of more than one polymer particle and has an agglomerate size of 10 to 100 μm.

[0086] Aspect 3. The chemical mechanical polishing pad as described in aspect 1 or 2, wherein the polymer particles comprise polytetrafluoroethylene.

[0087] Aspect 4: A chemical mechanical polishing pad as described in any of the preceding aspects, wherein the average size of the polymer particles is in the range of 1 to 20, preferably 1 to 10, more preferably 1 to 5 μm.

[0088] Aspect 5: A chemical mechanical polishing pad as described in any of the preceding aspects, wherein at least 80 percent of the agglomerates have a size of less than 10, preferably less than 5 μm.

[0089] Aspect 6: The chemical mechanical polishing pad as described in any of the preceding aspects, wherein the polishing layer includes a void space based on a volume percentage of less than 5, less than 1, less than 0.5, or less than 0.1% of the total volume of the polishing layer.

[0090] Aspect 7: A chemical mechanical polishing pad as described in any of the preceding aspects, wherein, according to ASTM D412-16 (2016), the polymer matrix has a tensile modulus of 50 to 200, preferably 50 to 150, and more preferably 50 to 120 MPa at 23°C.

[0091] Aspect 8: A chemical mechanical polishing pad as described in any of the preceding aspects, wherein, according to ASTM-5279-08, the polymer matrix has a tangent δ (tanδ) of 0.13 to 0.3 in the temperature range from 20°C to 40°C.

[0092] Aspect 9: A chemical mechanical polishing pad as described in any of the preceding aspects, wherein the polymer matrix has a Shore D hardness of 25 to 70, preferably 30 to 60, and more preferably 35 to 50, as measured, for example, according to ASTM D2240-15.

[0093] Aspect 10: A chemical mechanical polishing pad as described in any of the preceding aspects, wherein the polymer matrix comprises thermoplastic polyurethane.

[0094] Aspect 12: A chemical mechanical polishing pad as described in any of the preceding aspects, wherein the polishing layer has a Shore D hardness of 25 to 70, preferably 30 to 60, and more preferably 35 to 50, as measured according to ASTM D2240-15.

[0095] Aspect 13: A chemical mechanical polishing pad as described in any of the preceding aspects, wherein the polishing layer has a thickness of 500 to 1500, preferably 700 to 1200 N-mm. 2 The flexural stiffness, as measured by ASTM D7264 / D7264M-21.

[0096] Aspect 14: A chemical mechanical polishing pad as described in any of the preceding aspects, wherein at 30°C, the polishing layer has an elastic storage modulus (G') of less than 125 MPa, preferably 50 to 125, more preferably 50 to 100 MPa, as measured, for example, according to ASTM 5279-08.

[0097] Aspect 15: A chemical mechanical polishing pad as described in any of the preceding aspects, wherein the polishing layer has a thickness of 500 to 4000, preferably 700 to 3500, more preferably 1000 to 3000, and most preferably 1300 to 2500 μm.

[0098] Aspect 16: A chemical mechanical polishing pad as described in any of the preceding aspects, wherein, at 20°C, the tensile modulus of the polymer used in the polymer particles can be greater than 400, or greater than 500 up to 2000, up to 1500, or up to 1000 MPa.

[0099] Aspect 17: A chemical mechanical polishing pad as described in any of the preceding aspects, wherein the polymer particles have a Shore D hardness of 50 to 100 or 55 to 75.

[0100] Aspect 18: A chemical mechanical polishing pad as described in any of the preceding aspects, wherein the polishing layer has a Shore D hardness of 25 to 70, preferably 30 to 60, more preferably 35 to 50, as measured, for example, according to ASTM D2240-15.

[0101] Aspect 19. The chemical mechanical polishing pad as described in any of the preceding aspects, wherein the polishing layer has one or more of the following macroscopic textures: grooves, protrusions.

[0102] Aspect 20: A method comprising polishing a composite structure in which metallic features are surrounded by an insulating material using a pad as described in any of the preceding aspects.

[0103] Aspect 21. The method of aspect 20, wherein a portion of the metal feature has a size of 5-100 μm, and the polishing produces a structure in the metal feature with a dish-shaped recess having a diameter of less than 100 angstroms.

[0104] Aspect 22: The method as described in aspects 20 or 21, wherein the metallic feature comprises tungsten or copper.

[0105] Aspect 23. The method of any one of Aspects 20-22, wherein the polished layer has a polished roughness greater than 100 μm.

[0106] 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”). Unless otherwise specifically stated, all composition is expressed as a weight percentage (wt.%).

[0107] This disclosure may alternatively include any suitable components disclosed herein, or consist of or substantially consist of any suitable components disclosed herein. This disclosure may additionally or alternatively 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.

[0108] 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 derived from this application shall take precedence over the conflicting terminology derived from the incorporated reference.

[0109] 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 chemical mechanical polishing pad comprising a substantially non-porous polishing layer, the polishing layer comprising a polymeric matrix and agglomerates of polymeric particles embedded in the polymeric matrix, wherein the polymeric particles are present in an amount of 5 to 35 weight percent based on the weight of the polishing layer, the agglomerates have a size greater than 1 pm, the polymeric particles have a tensile modulus that is higher than the tensile modulus of the polymeric matrix, and the polishing layer is viscoelastic, the polymeric particles comprising a fluoropolymer selected from PTFE, PFA, FEP, PVF, ETFE, ECTFE, and combinations thereof.

2. The chemical mechanical polishing pad of claim 1, wherein, A fraction of the agglomerates comprise a plurality of the polymeric particles and have an agglomerate size of 10 to 100 pm.

3. The chemical mechanical polishing pad of claim 1 wherein, The polymeric particles comprise polytetrafluoroethylene.

4. The chemical mechanical polishing pad of claim 1 wherein, The polymeric matrix comprises a thermoplastic polyurethane.

5. The chemical mechanical polishing pad of claim 1 wherein, The energy loss factor GEL is from 1000 to 3000 Pa -1 .

6. The chemical mechanical polishing pad of claim 1 wherein, The polishing layer has a macrotexture of one or more of the following: grooves, protrusions.

7. The chemical mechanical polishing pad of claim 1 wherein, the polishing layer has a flexural rigidity of 500 to 1500 Newton-mm measured by ASTM D7264 / D7264M-21 2 .

8. A method comprising using the pad of claim 1 to polish a composite structure in which metal features are surrounded by insulating material.

9. The method of claim 8, wherein, A portion of the metal features have a size of 5-100 pm, and the polishing results in structures in the metal features having dish-shaped depressions of less than 100 angstroms.

10. The method of claim 8, wherein, The polishing layer has a post-polishing roughness of greater than 100 pm.

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