TW202246041A - Polishing pads having improved pore structure - Google Patents

Abstract

Embodiments herein generally relate to polishing pads and methods of forming polishing pads. A method of forming a polishing pad includes (a) dispensing droplets of a pre-polymer composition and droplets of a sacrificial material composition onto a surface of a previously formed print layer according to a predetermined droplet dispense pattern. The method includes (b) at least partially curing the dispensed droplets of the pre-polymer composition to form a print layer. The method includes (c) sequentially repeating (a) and (b) to form a polishing layer having a plurality of pore-features formed therein. The pre-polymer composition includes a multifunctional acrylate component. A curing rate of the dispensed droplets of the pre-polymer composition including the multifunctional acrylate component when exposed to a first dose of electromagnetic radiation is greater than a curing rate of the pre-polymer composition without the multifunctional acrylate component when exposed to the same first dose of electromagnetic radiation.

Description

Polishing pad with improved pore structure

Embodiments of the disclosure relate generally to polishing pads, and methods of making polishing pads, and more particularly, to polishing for chemical mechanical polishing (CMP) of substrates in electronic component manufacturing processes pad.

Chemical mechanical polishing (CMP) is generally used in the manufacture of high-density integrated circuits to planarize or polish material layers deposited on a substrate. A typical CMP process involves bringing the layer of material to be planarized into contact with the polishing pad and moving the polishing pad, the substrate, or both in the presence of a polishing fluid comprising abrasive particles, and thereby creating a direct opposing surface between the surface of the material layer and the polishing pad. move. One common application of CMP in semiconductor device fabrication is the planarization of bulk films, for example, pre-metal dielectric (PMD) or interlayer dielectric (interlayer dielectric (ILD)) polishing, where the underlying two-dimensional or The three-dimensional features form grooves and protrusions in the surface of the layer to be planarized. Other common applications of CMP in semiconductor device fabrication include shallow trench isolation (shallow trench isolation; STI) and interlevel metal interconnect formation, where CMP is used to remove exposed surfaces from layers in which STI or metal interconnect features are disposed ( field) to remove via, contact, or trench fill material.

Typically, the polishing pads used in the above-described CMP processes are selected based on the material properties of the polishing pad material and the suitability of those material properties for the desired CMP application. An example of a material property that can be adjusted to tune the performance of a polishing pad for a desired CMP application is the porosity and properties associated therewith (such as pore size and structure) and material surface relief of the polymeric material used to form the polishing pad body. A method of introducing porosity into a polishing pad material may include mixing a prepolymer composition with a porogen such as a water-soluble material or air, and then molding and curing the prepolymer composition into individual polishing pads or polymer cakes , and thereby machine (eg, turn) individual polishing pads.

The polishing pads can also be fabricated using techniques other than molding, such as via additive manufacturing. In the production of polishing pads using additive manufacturing techniques (e.g. 3D printing), droplets of prepolymer composition and droplets of porogen can be selectively and spatially deposited in multiple printed layers to form a polishing pad. Unfortunately, although additive manufacturing techniques can provide precise placement of pores within the formed pads, intermixing between adjacent droplets of the prepolymer composition and the porogen (especially when polishing is formed from relatively soft materials) In the case of pads) can lead to poor structure of the resulting holes, which can hinder performance tuning opportunities that might otherwise result.

Therefore, there is a need in the art for methods of improving the pore structure in polishing pads formed by additive manufacturing techniques.

Embodiments described herein generally relate to polishing pads that can be used in chemical mechanical polishing (CMP) processes, and methods for making polishing pads. More particularly, embodiments herein provide polishing pads with improved pore characteristics and additive manufacturing methods for forming the polishing pads.

In one embodiment, a method of forming a polishing pad includes (a) dispensing droplets of a prepolymer composition and droplets of a sacrificial material composition to a previously formed printed pad according to a predetermined droplet dispensing pattern. on the surface of the layer. The method includes (b) at least partially curing the dispensed droplets of the prepolymer composition to form a print layer. The method includes (c) sequentially repeating (a) and (b) to form a polishing layer having a plurality of hole features formed therein. The prepolymer composition includes a multifunctional acrylate component. Dispensed droplets of a prepolymer composition comprising a multifunctional acrylate component cure faster when exposed to a first dose of electromagnetic radiation than prepolymer compositions not having a multifunctional acrylate component when exposed to Curing rate at the same first dose of electromagnetic radiation. The plurality of pore features include openings defined in a surface of the polishing layer, voids formed in the polishing layer below the surface, pore-forming features comprising a sacrificial material composition, or combinations thereof.

In another embodiment, a method of forming a polishing pad includes (a) dispensing droplets of a prepolymer composition and droplets of a sacrificial material composition to previously formed columns according to a predetermined droplet dispensing pattern on the surface of the printing layer. The method includes (b) at least partially curing a dispensed droplet of a prepolymer composition to form a printed layer including a plurality of hole features. The method includes (c) repeating (a) and (b) in sequence to form a polishing layer. The prepolymer composition includes a surfactant. The volume of the hole feature space of an individual one of the plurality of hole features comprises at least 50% of the volume of the sacrificial material composition dispensed to form the corresponding hole feature. The plurality of pore features include openings defined in a surface of the polishing layer, voids formed in the polishing layer below the surface, pore-forming features comprising a sacrificial material composition, or combinations thereof.

In another embodiment, a polishing pad includes a plurality of polishing elements. Each polishing element includes an individual surface forming a portion of the polishing surface of the polishing pad; and one or more sidewalls extending downwardly from the individual surface to define a plurality of channels disposed between the polishing elements. A plurality of hole features are formed in each of the polishing elements. Each of the polishing elements is formed from a prepolymer composition and a sacrificial material composition. The volume of the hole feature space of an individual one of the plurality of hole features comprises at least 50% of the volume of the sacrificial material composition dispensed to form the corresponding hole feature. The plurality of pore features include openings defined in the polishing surface, voids formed in polishing elements below the polishing surface, pore-forming features comprising a sacrificial material composition, or combinations thereof.

Embodiments described herein generally relate to polishing pads that can be used in chemical mechanical polishing (CMP) processes, and methods for making polishing pads. In particular, the polishing pads described herein are characterized by improved pore structures compared to polishing pads formed using conventional methods.

Schematically illustrated in FIG. 1A are those commonly associated with polishing pads formed by conventional additive manufacturing techniques, especially those formed from relatively soft materials and/or using high-resolution printing. Undesired pore structure. FIG. 1A is a schematic cross-sectional view of a portion of a polishing layer 102a of an exemplary polishing pad. The polishing material 104a of the polishing layer 102a may include an insoluble polymer resulting from the polymerization of droplets of a prepolymer composition. A plurality of hole features 106a are formed in polishing material 104a by disposing droplets of sacrificial material composition in combination with droplets of prepolymer composition. Aperture feature 106a may include an opening defined in polishing surface 108a of polishing layer 102a. Pore features 106a are poorly defined here, e.g., have non-uniform diameters, non-uniform depths, non-uniform size distributions that vary across the entire pad, non-uniform shapes, flattened appearance in cross-section, polishing material 104a in (for example) parallel Merging across the hole features 106a in a direction at or perpendicular to the X-Y plane, discontinuities within each of the hole features 106a, low holes as a fraction of the volume of the sacrificial material composition dispensed to form the corresponding hole features Feature spaces, and combinations thereof.

The polishing layer 102a may be formed according to the print design layout for the polishing layer 102b to be printed shown in FIG. 1B. In FIG. 1B, each to-be-printed hole feature 106b extends through a plurality of printed layers 110a-110k that are stacked one on top of the other in the Z direction. According to FIG. 1B, printed layers 110a, 110c, 110e, and 110g include hole feature spaces corresponding to sacrificial material composition 112 disposed adjacent to droplets of prepolymer composition comprising polishing material 104b. droplet. Other printed layers (eg, 110b, 110d, and 110f) of non-porous feature spaces (ie, including only polishing material 104b) are interposed in the Z direction between printed layers 110a, 110c, 110e, and 110e in an alternating arrangement as shown. Between 110g. Each pair of alternating printed layers may have the same pattern, such that droplets of prepolymer composition and sacrificial material composition will be deposited at the same locations in each layer. Additional printing layers (eg, 110h˜110k) are disposed below the printing layer 110g. In some other embodiments, printed layers 110 a , 110 c , 110 e , and 110 g including hole feature spaces are stacked in direct contact with each other, and printed layers without hole feature spaces (eg, 110 b , 110 d , and 110 f ) are omitted. In such embodiments, droplets of sacrificial material composition 112 will be deposited at the same location in each layer such that sacrificial material composition 112 is continuous in the Z-direction within individual hole features 106b. The resulting pore features may be referred to as "pillars."

According to the design layout of FIG. 1B, the hole features 106b will be distributed relative to each other in one or both directions parallel to the X-Y plane of the polishing surface of the polishing pad (ie, laterally). Accordingly, at least portions of the hole features 106b will be spatially separated, ie, spaced from each other, by at least a portion of the polishing material to be printed 104b interposed therebetween. The hole feature 106b may be continuous with the polished surface 108b to be printed.

In general, the polishing pad 102b to be printed is designed to have well-defined pore features without any of the disadvantages evident in the resulting polishing layer 102a described above. It is believed that the poorly defined pore features 106a shown in Figure 1A are the result of intermixing between adjacent droplets of the prepolymer composition and sacrificial material composition prior to curing. Additionally, it is also believed that intermixing may more readily occur during the manufacture of polishing pads formed from relatively softer materials and/or formed using high resolution printing.

Advantageously, embodiments described herein provide for reduced intermixing between adjacent droplets of prepolymer composition and sacrificial material composition compared to the example shown in Figure 1A, resulting in better defined hole features. Additionally, the reduced intermixing results in the formation of a polishing layer 202 (eg, shown in Figure 2) that more closely corresponds to the to-be-printed polishing layer 102b shown in Figure IB.

FIG. 2 is a schematic cross-sectional view illustrating a portion of a polishing layer 202 of a polishing pad according to embodiments described herein. As described in more detail below, the polishing material 204 of the polishing layer 202 may comprise a hard or soft formulation. A plurality of hole features 206 are formed in polishing material 204 . Hole features 206 may include openings defined in polishing surface 208 of polishing layer 202, voids formed in polishing material 204 below polishing surface 208, hole-forming features disposed in polishing surface 208, holes disposed below polishing surface 208, Pore-forming features in polishing material 204, and combinations thereof. Here, well-defined hole features 206, for example, have one or more of the following: uniform diameter, uniform depth, uniform size distribution across the entire pad, circular appearance in cross-section, inserted in relative Separation of polishing material 204 between adjacent hole features 206, continuity within each of the hole features 206, high hole feature space as a fraction of the volume of the sacrificial material composition dispensed to form the corresponding hole features , less spread in radial planes (eg, in the X-Y plane) compared to hole features 106a, reduced depth compared to hole features 106a, and combinations thereof.

The embodiments described herein provide a general approach to modify pore structure independent of other aspects of the formulation, such as polarity of components, relative strength of polishing materials (e.g., storage modulus or ultimate tensile strength) ), additives for adjusting ζ (zeta) potential, additives for tuning water absorption, or monomers for tuning mechanical properties. Embodiments described herein improve hole structure even at high resolution printing such as 300 dpi or 600 dpi. Embodiments described herein provide polishing pads with improved surface curing that can reduce surface stickiness. Embodiments described herein provide polishing pads with reduced concentrations of potentially harmful residual monomers. Embodiments described herein provide polishing pads with reduced internal structural stress levels, which can improve the planarity of the polishing pad.

Embodiments described herein provide improved pore structure, even for polishing pads formed using relatively soft material formulations. It is believed that, during the conventional pad manufacturing process, the prepolymer droplets of the soft polishing material formulation are less compatible with the adjacent liquid of the sacrificial material due to the greater hydrophilicity of the soft material formulation when compared to the harder material formulation. The drops will suffer from increased intermixing. However, the embodiments described herein overcome the challenge of maintaining pore structure even with more hydrophilic formulations.

Embodiments described herein provide prepolymer compositions that include a multifunctional acrylate component that increases the dispensing of the prepolymer composition when exposed to a dose of electromagnetic radiation. The solidification rate of the droplet. In other words, when exposed to the same dose of electromagnetic radiation, the cure rate of the prepolymer composition with the multifunctional acrylate component is greater than the cure rate of the prepolymer composition without the multifunctional acrylate component. Advantageously, the accelerated curing of the prepolymer compositions in the embodiments described herein provides a combination of prepolymer compositions and sacrificial materials when compared to prepolymer compositions without the multifunctional acrylate component. Reduced intermixing between adjacent droplets of composition.

Advantageously, the embodiments described herein provide a prepolymer composition comprising a surfactant which, when compared to a prepolymer composition without a surfactant, provides a prepolymer composition with a sacrificial Reduced intermixing between adjacent droplets of material composition.

Embodiments described herein provide sacrificial material compositions that include a polyethylene glycol monoacrylate component that reduces the flowability of the resulting porogen phase after curing. Advantageously, the reduced flowability in the embodiments described herein improves the structure of the resulting pore features compared to polishing pads formed without the polyethylene glycol monoacrylate component.

Although the embodiments described herein generally relate to chemical mechanical polishing (CMP) pads used in semiconductor device fabrication, such polishing pads and methods of making them are also applicable to the use of chemically active and chemically inactive polishing fluids And/or other polishing process of polishing fluid without abrasive particles. Additionally, the embodiments described herein may be used individually or in combination in at least the following industries: aerospace, ceramics, hard disk drives (HDD), MEMS and nanotechnology, metal processing, optical components, and electro-optic components manufacturing and semiconductor device manufacturing, etc. Exemplary Polishing System

FIG. 3 is a schematic side view of an exemplary polishing system 300 configured to use a polishing pad 400 formed according to embodiments described herein. Polishing pad 400 is further depicted in FIG. 4 .

Here, polishing system 300 features a platform 304 having a polishing pad 400 secured thereto using a pressure sensitive adhesive and a substrate carrier 306 . Substrate carrier 306 faces platform 304 and polishing pad 400 mounted thereon. The substrate carrier 306 is used to push the material surface of the substrate 308 disposed therein against the polishing surface of the polishing pad 400 while simultaneously rotating about the carrier axis 310 . Generally, the platform 304 rotates about the platform axis 312 while the rotating substrate carrier 306 sweeps back and forth from the inner diameter to the outer diameter of the platform 304 to partially reduce uneven wear of the polishing pad 400 .

The polishing system 300 further includes a fluid delivery arm 314 and a pad conditioner assembly 316 . Fluid delivery arm 314 is positioned above polishing pad 400 and is used to deliver a polishing fluid, such as a polishing slurry with abrasive suspended therein, to the surface of polishing pad 400 . Usually, the polishing fluid contains pH regulators and other chemically active components (such as oxidizing agents) to achieve chemical mechanical polishing of the material surface of the substrate 308 . Pad conditioner assembly 316 is used to condition polishing pad 400 by pushing fixed abrasive conditioning disc 318 against the surface of polishing pad 400 before, after, or during polishing of substrate 308 . Pushing the conditioning disk 318 toward the polishing pad 400 includes rotating the conditioning disk 318 about the conditioner axis 320 and sweeping the conditioning disk 318 from the inner diameter of the platform 304 to the outer diameter of the platform 304 . The conditioning disc 318 is used to abrade and restore the polishing surface of the polishing pad 400 and remove polishing by-products or other debris from the polishing surface of the polishing pad 400 . Examples of polishing pads

The polishing pads described herein include a base layer and a polishing layer disposed on the base layer. The polishing layer forms the polishing surface of the polishing pad, and the base layer provides support for the polishing layer when the substrate to be polished is pushed against the polishing layer. The base layer and the polishing layer are formed from different prepolymer compositions that have different material properties when cured. The base layer and the polishing layer are integrally and sequentially formed using a continuous layer-by-layer additive manufacturing process. The additive manufacturing process provides the body of the polishing pad with a continuous polymer phase between the polishing layer and the base layer, thereby eliminating the need for an adhesive layer or other joining method in between. In some embodiments, the polishing layer is formed from a plurality of polishing elements separated from one another across the polishing surface by grooves and/or channels disposed therebetween.

As used herein, the term "pore feature" includes openings defined in the polishing surface, voids formed in the polishing material below the polishing surface, pore-forming features disposed in the polishing surface, polishing material disposed below the polishing surface Hole-forming features in , and combinations thereof. Pore-forming features typically include a water-soluble sacrificial material that dissolves when exposed to a polishing fluid, thereby forming corresponding openings in the polishing surface and/or voids in the polishing material below the polishing surface. In some embodiments, the water-soluble sacrificial material swells when exposed to the polishing fluid, thereby deforming the surrounding polishing material to provide asperities at the surface of the polishing pad material. The resulting pores and asperities ideally facilitate the transport of liquid and abrasives to the interface between the polishing pad and the surface of the substrate material to be polished, and temporarily immobilize those abrasives relative to the substrate surface (abrasive capture) to enable separation from the substrate surface. Chemical and mechanical material removal.

As used herein, the term "pore feature space" refers to the volume of each pore feature. When multiple hole features are merged together, the boundary lines defining the hole feature space of each individual hole feature can be determined according to the corresponding design layout of the polishing layer to be printed. For example, when two holes are merged together, the average distance between the holes to be printed can be used as the boundary line between the merged holes.

As used herein, the term "pore feature density" refers to the cumulative area comprising pore features in the X-Y plane of a given sample as a percentage of the total area of the given sample in the X-Y plane, such as included in the polishing surface of a polishing pad Cumulative area of the hole features in the hole feature density micro-region in or in the X-Y plane parallel to the polishing surface. As used herein, the term "porosity" indicates the volume of pore-featured spaces as a percentage of the total volume in a given sample. In embodiments where the pore features as defined herein include pore-forming features formed from a sacrificial material, the pore feature density and porosity are measured after dissolving therefrom the sacrificial material from which the features were formed.

The characteristic pore density, characteristic pore space, characteristic pore structure, porosity and pore size can be determined using any suitable method, such as by methods using scanning electron microscopy (SEM) or optical microscopy. Techniques and systems for characterizing pore characteristic density, porosity and pore size are well known in the art. For example, a portion of the surface can be characterized by any suitable method (eg, by electron microscope image analysis, by atomic force microscopy, by 3D microscopy, etc.). In one implementation, pore feature density and pore size analysis can be performed using a VK-X series 3D UV laser scanning confocal microscope manufactured by KEYENCE Corporation of America, Elmwood Park, NJ, USA.

In some embodiments, the polishing material of the polishing pad can be formed from different prepolymer compositions or different ratios of different prepolymer compositions to provide unique material properties.

In general, the methods described herein form (print) at least a portion of a polishing pad in a layer-by-layer process using an additive manufacturing system (eg, a 2D or 3D inkjet printer system). Typically, it is formed by sequentially depositing and at least partially curing droplets of the desired prepolymer composition and/or pore-forming sacrificial material precursor composition on a fabrication support or a previously formed print layer (column print) each print layer. Beneficially, the additive manufacturing system and methods described herein enable at least micron-scale drop placement control within each printed layer (X-Y resolution), and micron-scale (Z resolution) through the thickness of each printed layer ( 0.1 μm to 200 μm) control. The micron-scale X-Y and Z resolution provided by the additive manufacturing system and methods described herein facilitates the formation of desirable and repeatable patterns of the hole features described herein. Thus, in some embodiments, the additive manufacturing process used to form the polishing pad also imparts one or more superior structural properties to the polishing pad formed therefrom.

As used herein, the term "high resolution printing" refers to a well feature formed by four or fewer adjacent droplets of a sacrificial material composition, such as one to four adjacent droplets. Negative changes in pore structure associated with intermixing between droplets of prepolymer composition and sacrificial material composition are more pronounced when using high-resolution printing, as compared to lower-resolution printing In other words, the size of the hole features is substantially reduced.

FIG. 4 is a schematic isometric cross-sectional view of a polishing pad 400 featuring selectively arranged aperture features 410 according to embodiments described herein. The polishing pad 400 may be used as the polishing pad 400 of the exemplary polishing system 300 described in FIG. 3 . Here, polishing pad 400 includes a plurality of polishing elements 404 disposed on and partially within base layer 406 . The additive manufacturing process allows for the copolymerization of different prepolymer compositions used to separately form the base layer 406 and the polishing layer comprising the polishing elements 404, thereby providing a continuous phase of polymeric material across the interfacial boundary region therebetween.

The polishing pad 400 has a first thickness T(1) between about 5 mm and about 30 mm. Polishing element 404 is supported in the thickness direction of pad 400 by a portion of base layer 406 having a second thickness between about 1/3 and about 2/3 of first thickness T(1). T(2). The polishing element 404 has a third thickness T(3) that is about 1/3 to about 2/3 of the first thickness T(1). As shown, at least a portion of the polishing elements are disposed below the surface of the base layer 406 and the remainder extend a height H upwardly therefrom. In some embodiments, the height H is about 1/2 or less of the first thickness T(1).

Here, plurality of polishing elements 404 includes a plurality of discontinuous (segmented) concentric rings 407 disposed about and extending radially outward from post 405 . Here, pillar 405 is disposed at the center of polishing pad 400 . In other embodiments, the centers of the posts 405, and thus the centers of the concentric rings 407, may be offset from the center of the polishing pad 400 as the polishing pad 400 rotates on the polishing platform to provide a wiping-type relative motion between the substrate and the polishing pad surface. . The sidewalls of the plurality of polishing elements 404 and the upwardly facing surface of the base layer 406 define a plurality of channels 418 disposed in the polishing pad 400 between each of the polishing elements 404 and between the polishing elements 404. Between the plane of the polishing surface 401 of the pad 400 and the surface of the base layer 406 . Plurality of channels 418 enables distribution of polishing fluid across polishing pad 400 and to the interface between polishing pad 400 and the material surface of a substrate to be polished thereon. Here, polishing element 404 has an upper surface parallel to the X-Y plane and sidewalls that are substantially vertical, such as within about 20° of vertical (orthogonal to the X-Y plane), or within about 10° of vertical. The width W(1) of polishing element(s) 404 is between about 250 μm and about 10 mm, such as between about 250 μm and about 5 mm, or between about 1 mm and about 5 mm. Pitch P between polishing element(s) 404 is between about 0.5 mm and about 5 mm. In some embodiments, one or both of width W(1) and pitch P vary across the radius of polishing pad 400 to define regions of pad material properties.

Polishing element 404 includes a plurality of hole features 410 disposed therein. When viewed in cross-section, plurality of hole features 410 may be placed in any desired vertical arrangement. For example, in FIG. 4, a plurality of hole features 410 are vertically disposed in a divided row arrangement (two rows are shown), with the hole features 410 in each row being substantially vertically aligned. In some other examples, groups or individual columns of columns of hole features 410 in the depth direction of polishing element 404 may be offset in one or both of the X-Y directions to provide corresponding hole features below polishing surface 401 410, the corresponding hole features 410 are vertically staggered with respect to the hole features 410 disposed above and/or below them. The orientation of the hole features 410 can be advantageously used to adjust the compliance of the polishing material with respect to the direction of the applied load on the substrate being polished thereon. Thus, in one example, the staggered hole features 410 may be advantageously used to adjust and/or control the polish planarization performance of a polishing pad formed therefrom.

In some embodiments, individual well features 410 may have a height of about 600 μm or less, such as about 500 μm or less, about 400 μm or less, about 300 μm or less, about 200 μm or less, About 100 μm or less, about 50 μm or less, about 40 μm or less, about 30 μm or less, about 20 μm or less, or about 10 μm or less. The height of individual hole features 410 is typically a multiple of the thickness of each of the printed layers, eg, 1 or more. For example, the thickness of the hole features within the printed layer can be the same as the thickness of the continuous polymer phase of the polishing material disposed adjacent to it. Thus, if hole features disposed laterally within at least two sequentially deposited print layers are aligned in the Z direction or at least partially overlap, the thickness of the resulting hole feature is at least as thick as the at least two sequentially deposited print layers. The combined thickness of the layers. In some embodiments, one or more of the hole features does not overlap a hole feature in an adjacent layer disposed above or below it, and thus has the thickness of a single printed layer.

In some embodiments, individual well features 410 are formed to have a thickness of about 600 μm or less (eg, about 500 μm or less, about 400 μm or less, about 300 μm or less, about 200 μm or less, about 100 μm or less, about 50 μm or less, about 40 μm or less, about 30 μm or less, about 20 μm or less, or about 10 μm or less) and about 5 μm or more (eg, about 10 μm or more, about 25 μm or more, or about 50 μm or more) diameter D (measured in the X-Y plane). In some embodiments, the average diameter D of individual hole features 410 is between about 50 μm and about 600 μm. In some embodiments, the hole features 410 are formed relatively shallow in the X-Y plane compared to their height, for example, in some embodiments, the diameter D of an individual hole feature is about 2/3 or less of its height, Such as about 1/2 or less, or about 1/3 or less.

Here, individual ones of the plurality of hole features 410 are vertically spaced apart by one or more printed layers of polymer material 412 formed therebetween. In some embodiments, the vertical spacing between hole features 410 may be about 100 μm or less, such as about 40 μm or less, such as about 10 μm or less, or about 10 μm to about 40 μm . Once the sacrificial material used to form the hole feature is removed from the hole feature 410, the hole feature 410 can form a substantially closed-cell structure. In one example, the spacing in the vertical direction between hole features 410 may be about 40 μm. The 40 μm pitch may be formed by disposing four 10 μm printed layers of polymer material 412 between printed layers including hole features 410 . In another example, the spacing in the vertical direction between hole features 410 may be about 10 μm. The 10 μm pitch may be formed by disposing four 2.5 μm printed layers of polymer material 412 between printed layers including hole features 410 .

In other embodiments, one or more of the hole features 410, or portions thereof, are not spaced apart from one or more of the hole features 410 adjacent thereto, and thus once the sacrificial material is removed from the hole features 410 , forming a more porous structure. The one or more printed layers may have a thickness of about 5 μm or greater, such as about 10 μm or greater, 20 μm or greater, 30 μm or greater, 40 μm or greater, or 50 μm or greater big. Individual hole features 410 may be formed in a corresponding single printed layer, and thus have a height corresponding to the thickness of the printed layer, or may be formed in two or more adjacent printed layers to provide a height corresponding to the cumulative thickness thereof. Hole height for thickness.

Polishing element 404 is formed from a continuous polymer phase of polymer material 412 . The polymeric material 412 may have a relatively low storage modulus E' (ie, a soft cushion material), a relatively high storage modulus E' (ie, a hard cushion material), or a combination of relatively low and relatively high storage modulus E'. Relatively moderate storage modulus E' between energy moduli (ie, moderate gasket material). In some examples, polymeric material 412 may have a substantially homogeneous material composition. In some other examples, polymeric material 412 may include at least two prepolymer compositions, and thus include combinations of low, medium, or high storage modulus E' materials, that are mutually exclusive in one or more material properties. difference. The characterization of low, medium or high storage modulus E' materials (E'30) at temperatures around 30°C is summarized in Table 1 . Table 1 Low energy storage modulus composition Moderate Energy Storage Modulus Composition High energy storage modulus composition E'30 < 100 MPa, (for example, 1 MPa to 100 MPa) 100 MPa to 500 MPa >500 MPa, (for example, 500 MPa to 3000 MPa)

FIGS. 5A-5F are schematic plan views of various polishing element shapes 504a-504f that may be used with or in place of polishing elements 404 of polishing pad 400 described in FIG. The shape of elements 504a-504f. Each of FIGS. 5A-5F includes pixel maps with white areas (areas in white pixels) representing polishing elements 504a-504f and black areas (areas in black pixels) representing base layer 406. area).

In Figure 5A, polishing element 500a includes a plurality of concentric rings. In Figure 5B, polishing element 500b includes a plurality of segments of concentric rings. In Figure 5C, polishing elements 504c form a plurality of helices (four shown) extending from the center of polishing pad 500c to or near the edge of polishing pad 500c. In Figure 5D, a plurality of discrete polishing elements 504d are arranged in a spiral pattern on the base layer 406 of the polishing pad 500d.

In FIG. 5E , each of plurality of polishing elements 504 e includes a cylindrical post extending upwardly from base layer 406 . In other embodiments, the polishing elements 504e are of any suitable cross-sectional view shape, for example, circular, partially circular (e.g., arcuate), oval, Squares, rectangles, triangles, polygons, rows of irregular shapes, or combinations thereof. FIG. 5F illustrates a polishing pad 500f having a plurality of discrete polishing elements 504f extending upwardly from the base layer 406 . Polishing pad 500f in FIG. 5F is similar to polishing pad 500e except that some of polishing elements 504f are connected to form one or more closed circles. The one or more closed circles create dead spaces that retain polishing fluid during the CMP process. Additive manufacturing system and process example

Figure 6A is a schematic cross-sectional view of an additive manufacturing system that can be used to form the polishing pads described herein, according to some embodiments. Here, additive manufacturing system 600 features a movable manufacturing support 602 , a plurality of dispense heads 604 and 606 positioned above manufacturing support 602 , a curing source 608 , and a system controller 610 . In some embodiments, the dispensing heads 604, 606 move independently of each other and independently of the manufacturing support 602 during the polishing pad manufacturing process. Here, a first dispense head 604 and a second dispense head 606 are fluidly coupled to a first prepolymer composition 612, respectively, used to form the polymer material 412 and hole features 410 shown above in FIG. 4 Source and sacrificial material 614 source. In general, the additive manufacturing system 600 features at least one or more dispense heads (eg, a third dispense head, not shown) fluidly coupled to the second pre-polymerized base layer 406 used to form the base layer 406 described above. Composition source. In some embodiments, additive manufacturing system 600 includes as many dispense heads as desired to each dispense a different prepolymer composition or sacrificial material precursor composition. In some embodiments, additive manufacturing system 600 further includes a plurality of dispensing heads, wherein two or more dispensing heads are configured to dispense the same prepolymer composition or sacrificial material precursor composition.

Here, each of the dispense heads 604, 606 is characterized by an array of drop ejection nozzles 616 configured to eject the respective prepolymer composition 612 and sacrificial material that have been delivered to the dispense head reservoir Droplets 630, 632 of composition 614. Here, the droplets 630 , 632 are sprayed towards the fabrication support and thus onto the fabrication support 602 or onto a previously formed printing layer 618 disposed on the fabrication support 602 . Generally, each of the dispensing heads 604, 606 is configured to emit droplets 630, 632 from each of the nozzles 616 (controlling their ejection) in a corresponding geometric array or pattern independently of the firing of its other nozzles 616. ). Here, as the dispensing heads 604, 606 move relative to the fabrication support 602, the nozzles 616 are independently fired according to the droplet dispensing pattern of the print layer to be formed (eg, print layer 624). Once dispensed, the droplets 630 of the prepolymer composition 612 and/or the droplets 632 of the sacrificial material composition 614 are provided by the curing source 608 (e.g., an electromagnetic radiation source, such as a UV radiation source) by exposure to Electromagnetic radiation (eg, UV radiation 626 ) is at least partially cured to form a printed layer (eg, partially formed printed layer 624 ).

In some embodiments, dispensed droplets of the prepolymer composition (such as the dispensed droplets 630 of the prepolymer composition 612) are exposed to electromagnetic radiation to spread the droplets to an equilibrium size (such as in The droplet is physically immobilized before it is described in the description of Figure 6B). Typically, the dispensed droplets are exposed to electromagnetic radiation for 1 second or so within the time the droplets contact a surface, such as the surface of the fabrication support 602 or a previously formed printing layer 618 disposed on the fabrication support 602 . In a shorter time, its prepolymer composition is at least partially cured.

Figure 6B is a close-up cross-sectional view schematically illustrating a droplet 630 disposed on a surface 618a of a previously formed layer, such as the previously formed layer 618 described in Figure 6A, in accordance with some embodiments . In a typical additive manufacturing process, a droplet of prepolymer composition, such as droplet 630a, spreads out and reaches the surface of the previously formed layer within about one second from the moment droplet 630a contacts surface 618a. The equilibrium contact angle α of 618a. The equilibrium contact angle α is a function of at least the material properties of the prepolymer composition and the energy at the surface 618a of a previously formed layer (eg, previously formed layer 618 ) (surface energy). In some embodiments, in order to fix the droplet contact angle with the surface 618a of a previously formed layer, it is desirable to at least partially solidify the dispensed droplet before it reaches an equilibrium size. In these embodiments, the contact angle Θ of the immobilized droplet 630b is greater than the equilibrium contact angle a of a droplet 630a of the same prepolymer composition that is allowed to spread to its equilibrium size.

Herein, at least partial curing of the dispensed droplets results in at least partial polymerization, e.g., cross-linking of the prepolymer composition(s) within the droplet and the same or different prepolymer compositions disposed adjacently The cross-linking of the droplets to form a continuous polymer phase. In some embodiments, prior to dispensing the sacrificial material composition into the desired well, a prepolymer composition is dispensed and at least partially cured to form a well around the desired well. Formulation and Material Examples

The prepolymer compositions used to form the base layer 406 and the polymer material 412 of the polishing element each include one of a functional polymer, a functional oligomer, a functional monomer, a reactive diluent, and a photoinitiator or a mixture of more.

Examples of suitable functional polymers that can be used to form one or both of the at least two prepolymer compositions include multifunctional acrylates, including di-, tri-, tetra-, and higher-functionality acrylates, such as 1, 3,5-Triacryloylhexahydro-1,3,5-triazine or trimethylolpropane triacrylate.

Examples of suitable functional oligomers that can be used to form either or both of the at least two prepolymer compositions include monofunctional and polyfunctional oligomers, acrylate oligomers, such as aliphatic urethane ester acrylate oligomer, aliphatic hexafunctional urethane acrylate oligomer, diacrylate, aliphatic hexafunctional urethane acrylate oligomer, multifunctional urethane acrylate oligomer, ester Urethane diacrylate oligomers, aliphatic urethane acrylate oligomers, aliphatic polyester urethane diacrylate blends and aliphatic diacrylate oligomers compounds, or combinations thereof, such as bisphenol-A ethoxylate diacrylate or polybutadiene diacrylate, tetrafunctional acrylated polyester oligomers, aliphatic polyester-based urethanes Diacrylate oligomers, and aliphatic polyester-based acrylates and diacrylates.

Examples of suitable monomers that may be used to form one or both of the at least two prepolymer compositions include monofunctional monomers and polyfunctional monomers. Suitable monofunctional monomers include tetrahydrofurfuryl acrylate (eg, ^SR285 from Sartomer®), tetrahydrofurfuryl methacrylate, vinyl caprolactam, isobornyl acrylate, isobornyl methacrylate, 2 -Phenoxyethyl ester, 2-phenoxyethyl methacrylate, 2-(2-ethoxyethoxy)ethyl acrylate, isooctyl acrylate, isodecyl acrylate, isodecyl methacrylate , lauryl acrylate, lauryl methacrylate, stearyl acrylate, stearyl methacrylate, cyclic trimethylolpropane formal acrylate, 2-[[(butylamino)carbonyl]oxy ] ethyl acrylate (eg Genomer 1122 from RAHN USA), 3,3,5-trimethylcyclohexane acrylate or monofunctional methoxylated PEG (350) acrylate. Suitable polyfunctional monomers include diols and diacrylates or dimethacrylates of polyether diols, such as propoxylated neopentyl glycol diacrylate, 1,6-hexanediol diacrylate, 1 ,6-hexanediol dimethacrylate, 1,3-butanediol diacrylate, 1,3-butanediol dimethacrylate, 1,4-butanediol diacrylate, 1,4 -Butanediol dimethacrylate, alkoxylated aliphatic diacrylates (eg, ^SR9209A from Sartomer®), diethylene glycol diacrylate, diethylene glycol dimethacrylate, dipropylene glycol diacrylate ester, tripropylene glycol diacrylate, triethylene glycol dimethacrylate, alkoxylated hexanediol diacrylate or combinations thereof, for example, ^SR562 , SR563, SR564 from Sartomer®.

Typically, the reactive diluent used to form one or more of the prepolymer compositions is minimally monofunctional and polymerizes upon exposure to free radicals, Lewis acids, and/or electromagnetic radiation. Examples of suitable reactive diluents include monoacrylate, 2-ethylhexyl acrylate, octyldecyl acrylate, cyclic trimethylolpropane formal acrylate, caprolactone acrylate, isobornyl acrylate ( IBOA) or alkoxylated lauryl methacrylate.

Examples of suitable photoinitiators for forming one or more of at least two different prepolymer compositions include polymeric photoinitiators and/or oligomeric photoinitiators, such as benzoin ethers, benzyl Ketones, acetophenones, alkylphenones, phosphine oxides, benzophenone compounds, and thioxanthone compounds (which include amine synergists), or combinations thereof.

Examples of polishing pad materials formed from the above prepolymer compositions generally include oligomers and/or polymer segments, compounds, or materials selected from the group consisting of polyamide, polycarbonate, polyamide Ester, polyetherketone, polyether, polyoxymethylene, polyethersulfone, polyetherimide, polyimide, polyolefin, polysiloxane, polysulfone, polyphenylene, polyphenylene sulfide, aminomethyl ester, polystyrene, polyacrylonitrile, polyacrylate, polymethylmethacrylate, urethane acrylate, polyacrylate acrylate, epoxy acrylate, polycarbonate, polyester, melamine, poly Sulfone, polyethylene materials, acrylonitrile butadiene styrene (ABS), halide polymers, block and random copolymers, and combinations thereof.

Sacrificial material composition(s) that may be used to form the pore features 410 described above include water soluble materials such as glycols (eg, polyethylene glycol), glycol ethers, and amines. Examples of suitable sacrificial material precursors that can be used to form the pore-forming features described herein include ethylene glycol, butylene glycol, dimer glycol, propylene glycol-(1,2) and propylene glycol-(1,3), octane- 1,8-diol, neopentyl glycol, cyclohexanedimethanol (1,4-bis-methylolcyclohexane), 2-methyl-1,3-propanediol, glycerin, trimethylolpropane , hexanediol-(1,6), hexanetriol-(1,2,6) butanetriol-(1,2,4), trimethylolethane, pentaerythritol, quinitol , mannitol and sorbitol, methyl glucoside, and diethylene glycol, triethylene glycol, tetraethylene glycol, polyethylene glycol, dibutylene glycol. Polytetramethylene glycol, ethylene glycol, ethylene glycol monobutyl ether (EGMBE), diethylene glycol monoethyl ether, ethanolamine, diethanolamine (DEA), triethanolamine (TEA), and combinations thereof.

In some embodiments, sacrificial material precursors include water-soluble polymers such as 1-vinyl-2-pyrrolidone, vinylimidazole, polyethylene glycol diacrylate, acrylic acid, sodium styrene sulfonate, Hitenol BC10 ®, Maxemul 6106 ^® , hydroxyethyl acrylate and [2-(methacryloxy)ethyltrimethylammonium chloride, sodium 3-allyloxy-2-hydroxy-1-propanesulfonate, 4 -Sodium vinylbenzenesulfonate, [2-(methacryloxy)ethyl]dimethyl-(3-sulfopropyl)ammonium hydroxide, 2-acrylamido-2-methyl-1 - Propane Sulfonic Acid, Vinyl Phosphonic Acid, Allyl Triphenyl Chloride, (Vinylbenzyl) Trimethyl Ammonium Chloride, Allyl Triphenyl Chloride, (Vinylbenzyl) Trimethyl Ammonium Chloride Ammonium Chloride, E-SPERSE RS-1618, E-SPERSE RS-1596, Methoxypolyethylene Glycol Monoacrylate, Methoxypolyethylene Glycol Diacrylate, Methoxypolyethylene Glycol Triacrylate , or a combination thereof. Exemplary Prepolymer Composition - Multifunctional Acrylate Component

In some examples, prepolymer composition 612 includes a multifunctional acrylate component, such as tripropylene glycol diacrylate, poly(propylene glycol) diacrylate (e.g., having a range), trimethylol triacrylate, neopentyl glycol diacrylate, ethoxylated neopentyl glycol diacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, or combinations thereof. In some examples, the multifunctional acrylate component can include at least one diacrylate or triacrylate having an Large (eg, about 350 g/mol to about 2000 g/mol) molecular weight. In some examples, the concentration of the multifunctional acrylate component in prepolymer composition 612 can be about 20 wt% or less, such as about 10 wt% or less, or about 10 wt% to about 20 wt%. In some examples, the prepolymer composition 612 further includes at least one of phenoxyethyl acrylate, tetrahydrofurfuryl acrylate, butyl urethane acrylate, isobornyl acrylate, or combinations thereof.

In some examples, dispensed droplets 630 of prepolymer composition 612 including the multifunctional acrylate component cure faster than prepolymer compositions without the multifunctional acrylate component when exposed to a first dose of electromagnetic radiation. The cure rate of the polymer composition 612 when exposed to the same first dose of electromagnetic radiation. In some examples, when cured, the prepolymer composition 612 can form a A polymer having a Shore A hardness of about 20, about 20 to about 40, about 40 to about 60, about 60 to about 80, or about 80 to about 100.

In some examples, at least partial curing of the dispensed droplets 630 of the prepolymer composition 612 includes exposing the dispensed droplets 630 to electromagnetic radiation for a first period of time from about 2 seconds to about 4 seconds, and having The cure rate of the prepolymer composition 612 of the multifunctional acrylate component corresponds to a conversion of about 50% to about 70% of the multifunctional acrylate component during the first time period.

In some examples, the volume of the hole feature space of an individual of the plurality of hole features 410 is at least 50%, at least 60%, at least 70% of the volume of the sacrificial material composition 614 dispensed to form the corresponding hole feature 410 , at least 80%, or at least 90%, or about 50% to about 60%, about 60% to about 70%, about 70% to about 80%, about 80% to about 90%, or about 90% to about 100% %.

In some examples, when compared to the cure rate of prepolymer composition 612 without the multifunctional acrylate component, the cure rate of the prepolymer composition 612 with the multifunctional acrylate component reduces the rate of prepolymerization. Intermixing between adjacent droplets 630, 632 of the material composition 612 and the sacrificial material composition 614.

In some examples, the cure rate of the prepolymer composition 612 having the multifunctional acrylate component satisfies the requirement for intermixing between adjacent droplets 630, 632 of the prepolymer composition 612 and the sacrificial material composition 614. Threshold condition. In some examples, the intermixing threshold condition corresponds to the volume of the hole feature space of an individual of the plurality of hole features 410, which is the volume of the sacrificial material composition 614 dispensed to form the corresponding hole feature 410 At least 50%, at least 60%, at least 70%, at least 80%, or at least 90%, or about 50% to about 60%, about 60% to about 70%, about 70% to about 80%, about 80% of to about 90%, or about 90% to about 100%.

In some examples, at least 5%, at least 10%, at least 20%, at least 20%, At least 30%, at least 40%, or at least 50% are isolated from others of the plurality of hole features within the polishing layer.

In some examples, the multifunctional acrylate component reduces polishing pad 400 when exposed to an aqueous polishing fluid when compared to a polishing pad formed using prepolymer composition 612 without the multifunctional acrylate component. of swelling.

In some examples, the multifunctional acrylate component increases the surface contact of water droplets disposed on the polishing layer as compared to a polishing layer formed using prepolymer composition 612 without the multifunctional acrylate component. angle. Exemplary Prepolymer Composition - Surfactant

In some examples, the prepolymer composition 612 includes surfactants such as polybutylphenol, nonylphenol, 2-methyl-4-trioctylphenol, 4,6-di-tert-butyl-2- methylphenol or combinations thereof. In some examples, the concentration of surfactant in prepolymer composition 612 may be about 1 wt% or less, such as about 0.1 wt% or less, or about 0.1 wt% to about 1 wt%.

In some examples, the surfactant increases the hydrophobicity of the dispensed droplets 630 of the prepolymer composition 612 . In some examples, the volume of the hole feature space of an individual of the plurality of hole features 410 is at least 50%, at least 60%, at least 70% of the volume of the sacrificial material composition 614 dispensed to form the corresponding hole feature 410 , at least 80%, or at least 90%, or about 50% to about 60%, about 60% to about 70%, about 70% to about 80%, about 80% to about 90%, or about 90% to about 100% %. Exemplary Sacrificial Material Composition - Polyethylene Glycol Monoacrylate Component

In some examples, sacrificial material composition 614 includes a polyethylene glycol monoacrylate component. The concentration of the polyethylene glycol monoacrylate component in the sacrificial material composition 614 may be about 30 wt% or greater, about 40 wt% or greater, or about 50 wt% or greater. In some examples, the molecular weight of the polyethylene glycol monoacrylate component can be from about 400 g/mol to about 1200 g/mol, such as from about 400 g/mol to about 750 g/mol.

In some examples, the sacrificial material composition 614 may further include a polyethylene glycol diacrylate component, a polyethylene glycol component, or combinations thereof. In some examples, the concentration of the polyethylene glycol diacrylate component in the sacrificial material composition may be about 30 wt% or less, about 20 wt% or less, or about 10 wt% or less. In some examples, the concentration of the polyethylene glycol component in the sacrificial material composition may be about 40 wt% or less, about 30 wt% or less, or about 20 wt% or less. In one example, the concentration of the polyethylene glycol monoacrylate component in the sacrificial material composition can be about 30 wt% or greater, and the concentration of the polyethylene glycol diacrylate component in the sacrificial material composition can be It is about 10 wt% or less, and the concentration of the polyethylene glycol component in the sacrificial material composition can be about 40 wt% or less. In some examples, when cured, the sacrificial material composition 614 may form a polymer having a Shore A hardness greater than 1, greater than 5, or greater than 10 (eg, from 10 to 100) at room temperature.

In some examples, the polymer is water soluble and exposing the polymer to an aqueous solution forms pores in the polishing layer. In some examples, sacrificial material composition 614 forms a linear polymer matrix when cured. In some examples, the prepolymer composition 612 may include at least one of phenoxyethyl acrylate, tetrahydrofurfuryl acrylate, butyl urethane acrylate, isobornyl acrylate, or a combination thereof.

In some examples, the volume of the hole feature space of individual ones of the plurality of hole features 410 is the volume of the sacrificial material composition 614 (including the polyethylene glycol monoacrylate component) dispensed to form the corresponding hole features 410 At least 50%, at least 60%, at least 70%, at least 80%, or at least 90%, or about 50% to about 60%, about 60% to about 70%, about 70% to about 80%, about 80% of to about 90%, or about 90% to about 100%.

Here, the additive manufacturing system 600 shown in FIG. 6A further includes a system controller 610 to direct its operation. System controller 610 includes a programmable central processing unit (CPU) 634 operable with memory 635 (eg, non-volatile memory) and support circuitry 636 . Support circuitry 636 is conventionally coupled to CPU 634 and includes cache memory coupled to various components of additive manufacturing system 600, clock circuits, input/output subsystems, power supplies, and the like, and combinations thereof , to facilitate control of the additive manufacturing system 600 . CPU 634 is one of any form of general-purpose computer processor (such as a programmable logic controller (PLC)) used in an industrial environment for controlling the various components and sub-assemblies of additive manufacturing system 600. processor. The memory 635 coupled to the CPU 634 is non-transitory and is usually one or more of commercially available memories, such as random access memory (random access memory; RAM), read only memory (read only memory; ROM), floppy disk drive, hard disk, or any other form of digital storage, whether local or remote.

Typically, memory 635 is in the form of a computer-readable storage medium (eg, non-volatile memory) containing instructions that, when executed by CPU 634 , facilitate the operation of manufacturing system 600 . The instructions in memory 635 are in the form of a program product, such as a program that implements the methods of the present disclosure.

The code may conform to any of a number of different programming languages. In one example, the present disclosure can be implemented as a program product stored on a computer readable storage medium for use with a computer system. The program(s) of the program product define functions of the embodiments (including the methods described herein).

Illustrative computer-readable storage media include, but are not limited to: (i) non-writable storage media that permanently store information (for example, read-only disk, flash memory, ROM chip, or any type of solid-state non-volatile semiconductor memory); and (ii) a writable storage medium that stores changeable information (for example, a floppy disk within a floppy disk drive or a hard disk drive , or any type of solid state random access semiconductor memory). Such a computer-readable storage medium, when carrying computer-readable instructions that direct the function of the methods described herein, is an embodiment of the disclosure. In some embodiments, the methods or portions described herein are implemented by one or more application specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or Other types of hardware implementations to perform. In some other embodiments, the polishing pad manufacturing systems described herein are implemented by a combination of software routines, ASIC(s), FPGA, and/or other types of hardware implementations.

Here, the system controller 610 directs the movement of the manufacturing support 602, the movement of the dispensing heads 604 and 606, the firing of droplets of the prepolymer composition from the nozzle 616, and the UV radiation provided by the source 608. The degree and timing of solidification of the dispensed droplets. In some embodiments, the instructions used by the system controller to direct the operation of the manufacturing system 600 include droplet dispensing patterns for each of the printing layers to be formed. In some embodiments, the droplet dispensing pattern is collectively stored in memory 635 as a CAD compatible digital print order.

7 is a flowchart illustrating a method of forming a printing layer of a polishing pad according to embodiments described herein. Embodiments of the method 700 may be used in conjunction with one or more of the systems and system operations described herein, such as the additive manufacturing system 600 of FIG. 6A and the immobilization of droplets of FIG. 6B. Additionally, embodiments of method 700 may be used to form any one or combination of the embodiments of polishing pads shown and described herein.

At activity 710, method 700 includes dispensing droplets of a prepolymer composition and droplets of a sacrificial material composition onto a surface of a previously formed print layer according to a predetermined drop dispensing pattern.

At activity 720, method 700 includes at least partially curing the dispensed droplet of prepolymer composition to form a printed layer including a plurality of hole features.

In some embodiments, method 700 further includes sequential repetitions of activities 710 and 720 to form print layers in the Z direction (i.e., normal to the surface of the fabrication support or to a previously formed print layer disposed thereon). Direction) stacked multiple print layers. The predetermined drop dispense pattern used to form each printed layer may be the same as or different from the predetermined drop dispense pattern used to form the previous printed layer disposed therebeneath. In some embodiments, the plurality of printing layers includes a polishing layer having the plurality of hole features formed therein. In some embodiments, the plurality of printing layers includes a polishing layer having a plurality of hole-forming features formed therein, wherein the plurality of hole-forming features include a sacrificial material composition.

Ideally, the prepolymer composition embodiments described herein that include a multifunctional acrylate component provide accelerated cure when compared to conventional prepolymer compositions, as shown in Figure 8 for conversion - Exposure curves are shown graphically.

Figure 8 is a graph 800 illustrating conversion-exposure curves 802a-802b for a prepolymer composition without a multifunctional acrylate component, and with a multifunctional acrylate component at a concentration of about 10 wt%. The conversion-exposure curves 804a-804b of the corresponding prepolymer composition. In the example illustrated in FIG. 8 , droplets of a prepolymer composition and a sacrificial material composition can be dispensed and cured, for example, according to method 700 . In this example, the sacrificial material composition may form about 16% of the total volume of the dispensed droplets.

In the example of Figure 8, the dispensed droplets are exposed to a series of pulses of electromagnetic radiation pulses (eg, UV radiation), each pulse having a fixed energy (dose). Thus, the exposure time (x-axis) corresponds to the cumulative dose of electromagnetic radiation applied to the dispensed droplets, and the conversion of the multifunctional acrylate component (y-axis) is measured as a function of the cumulative dose. In this example, conversion can indicate the degree of chemical crosslinking of the UV curable composition as measured by optical differential scanning calorimetry (DSC).

As shown in Figure 8, when compared to the corresponding conversion-exposure curves 802a-802b for prepolymer compositions without the multifunctional acrylate component, the prepolymer composition with the multifunctional acrylate component The conversion-exposure curves of the compounds are beneficially shifted towards increasing conversion at the same exposure time (cumulative dose). In some examples, the initial cure rate (which corresponds to the initial slope of the conversion-exposure curve) is increased by a factor of about 2 or more, or from about 1 to about 2, such as from about 1.6 to about 1.95. In one example, the ratio of the cure rate of the prepolymer composition with the multifunctional acrylate component to the cure rate of the prepolymer composition without the multifunctional acrylate component can be about 1.6 or greater, as About 1.6 to about 1.95.

Table 2 shows the hardness and pore feature space % (i.e., the volume of the pore feature space of individual ones of the plurality of pore features as a function of the amount of pore space dispensed to form the corresponding pores) for polishing pads formed using the prepolymer composition of FIG. 8 The fraction of the volume of the sacrificial material composition of the characteristic) value. Table 2 Prepolymer composition Hardness (Shore A) The ratio of the pore feature space to the volume of the sacrificial material composition dispensed to form the corresponding pore feature 802a 53 <50% 804a 70 >50% 802b 57 <50% 804b 68 >50%

While the foregoing is directed to embodiments of the disclosure, other and further embodiments of the disclosure can be devised without departing from the basic scope of the disclosure, and the scope of the disclosure is determined by the claims below.

112: Sacrificial material composition 202: polishing layer 204: polishing material 206: Hole feature 208: polished surface 300: Polishing system 304: platform 306: substrate carrier 308: Substrate 310: carrier axis 312: Platform axis 314: Fluid transfer arm 316: Pad Adjuster Assembly 318: Adjustment disc 320: Regulator axis 400: polishing pad 401: polished surface 404: polishing element 405: column 406: base layer 407: concentric ring 410: Hole Features 412: polymer material 418: channel 600: Additive Manufacturing Systems 602: Manufacturing supports 604: dispensing head 606: dispensing head 608: Curing source 610: System Controller 612: Prepolymer composition 614: Sacrificial material composition 616: Nozzle 618:Print layer 624:Print layer 626:UV radiation 630: droplet 632: droplet 634: central processing unit 635: memory 636: support circuit 700: method 710: activity 720: Activity 800: Curve 102a: polishing layer 102b: polishing layer 104a: Polishing material 104b: Polishing material 106a: Hole Features 106b: Hole feature 108a: polished surface 108b: polished surface 110a: printing layer 110c: printing layer 110g: printing layer 500a: polishing element 500b: Polishing element 500c: polishing pad 500d: polishing pad 500e: polishing pad 500f: polishing pad 504c: Polishing elements 504d: Discontinuous polishing elements 504e: Polishing elements 504f: polishing element 618a: Surface 630a: Droplet 110a-k: printing layer 504a-f: Polishing elements

So that the manner in which the above recited features of the disclosure can be understood in detail, a more particular description of the disclosure, briefly summarized above, can be had by reference to embodiments, some of which are illustrated in the accompanying drawings. It is to be noted, however, that the appended drawings illustrate only typical embodiments of the disclosure and are therefore not to be considered limiting of its scope, for the disclosure may admit to other equally effective embodiments.

FIG. 1A is a schematic cross-sectional view of a portion of a polishing layer of an illustrative polishing pad.

FIG. 1B is a schematic cross-sectional view illustrating a design layout of a polishing layer of a polishing pad (eg, the polishing pad of FIG. 1A ) to be printed.

Figure 2 is a schematic cross-sectional view illustrating a portion of a polishing layer of a polishing pad according to embodiments described herein.

Figure 3 is a schematic side view of an exemplary polishing system configured to use polishing pads formed according to embodiments described herein.

Figure 4 is a schematic isometric cross-sectional view of a polishing pad featuring a cross-sectional view of selectively arranged holes according to an embodiment described herein.

FIGS. 5A-5F are schematic plan views of various polishing pad designs that may be used in place of the pad design shown in FIG. 4 according to embodiments described herein.

Figure 6A is a schematic cross-sectional view of an additive manufacturing system that can be used to form the polishing pads described herein.

Figure 6B is a close-up cross-sectional view schematically illustrating a droplet disposed on the surface of a previously formed printing layer, according to embodiments described herein.

7 is a flowchart illustrating a method of forming a polishing pad according to embodiments described herein.

Figure 8 is a graph illustrating conversion versus exposure curves for prepolymer compositions with and without a multifunctional acrylate component.

To facilitate understanding, identical reference numerals have been used, where possible, to denote identical elements that are common to the figures. It is contemplated that elements and features of one implementation may be beneficially incorporated in other implementations without further recitation.

Domestic deposit information (please note in order of depositor, date, and number) none Overseas storage information (please note in order of storage country, institution, date, and number) none

400: polishing pad

401: polished surface

404: polishing element

405: column

406: base layer

407: concentric ring

410: Hole Features

412: polymer material

418: channel

Claims (20)

A method of forming a polishing pad, comprising the steps of: (a) dispensing droplets of a prepolymer composition and droplets of a sacrificial material composition onto a surface of a previously formed printing layer according to a predetermined droplet dispensing pattern; and (b) at least partially curing the dispensed droplets of the prepolymer composition to form a printed layer; and (c) repeating (a) and (b) in sequence to form a polishing layer having a plurality of hole features formed therein, wherein: The prepolymer composition includes a multifunctional acrylate component, The dispensed droplets of the prepolymer composition including the multifunctional acrylate component have a cure rate greater than that of the prepolymer composition without the multifunctional acrylate component when exposed to a first dose of electromagnetic radiation. a curing rate of the prepolymer composition when exposed to the same first dose of electromagnetic radiation, and The plurality of pore features include openings defined in a surface of the polishing layer, voids formed in the polishing layer below the surface, pore-forming features comprising the sacrificial material composition, or combinations thereof. The method of claim 1, wherein a concentration of the multifunctional acrylate component in the prepolymer composition is about 20 wt% or less. The method of claim 1, wherein the multifunctional acrylate component comprises at least one diacrylate or triacrylate having a molecular weight of about 200 g/mol or greater. The method as claimed in item 1, wherein the multifunctional acrylate component comprises tripropylene glycol diacrylate, poly(propylene glycol) diacrylate, trimethylol triacrylate, neopentyl glycol diacrylate, ethoxylate at least one of neopentyl glycol diacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate or a combination thereof. The method of claim 1, wherein the curing rate of the prepolymer composition with the multifunctional acrylate component is the same as the curing rate of the prepolymer composition without the multifunctional acrylate component One ratio is about 1.6 or greater. The method of claim 1, wherein a volume of a hole feature space of an individual of the plurality of hole features comprises at least 50% of a volume of the sacrificial material composition dispensed to form the corresponding hole feature . The method as described in claim 1, when compared with the curing rate of the prepolymer composition without the multifunctional acrylate component, the prepolymer composition with the multifunctional acrylate component The solidification rate reduces intermixing between adjacent droplets of the prepolymer composition and the sacrificial material composition. The method as described in Claim 1, wherein: the cure rate of the prepolymer composition having the multifunctional acrylate component satisfies a threshold condition for intermixing between adjacent droplets of the prepolymer composition and the sacrificial material composition, The threshold condition of intermixing corresponds to a volume of the pore feature space of an individual of the plurality of pore features, the volume comprising at least 50% of a volume of the sacrificial material composition dispensed to form the corresponding pore feature %. The method of claim 1, wherein when the curing rate of the prepolymer composition having the multifunctional acrylate component meets or exceeds a critical curing rate, at least 5% of the plurality of hole features isolated from others of the plurality of hole features within the polishing layer. The method according to claim 1, wherein the prepolymer composition further comprises at least one of phenoxyethyl acrylate, tetrahydrofurfuryl acrylate, butyl urethane acrylate, isobornyl acrylate or a combination thereof By. The method of claim 1, when compared to a polishing pad formed using the prepolymer composition without the multifunctional acrylate component, when exposed to an aqueous polishing fluid, the multifunctional acrylic The ester component reduces swelling of the polishing pad. As in the method described in claim 1, compared with a polishing layer formed by using the prepolymer composition without the multifunctional acrylate component, the multifunctional acrylate component increases the placement on the A surface contact angle of a drop of water on the polishing layer. A method of forming a polishing pad, comprising the steps of: (a) dispensing droplets of a prepolymer composition and droplets of a sacrificial material composition onto a surface of a previously formed printing layer according to a predetermined droplet dispensing pattern; and (b) at least partially curing the dispensed droplets of the prepolymer composition to form a printed layer including a plurality of hole features; and (c) Repeat (a) and (b) in order to form a polishing layer, wherein: The prepolymer composition includes a surfactant, wherein a volume of a hole feature space of an individual of the plurality of hole features comprises at least 50% of a volume of the sacrificial material composition dispensed to form the corresponding hole feature; and The plurality of pore features include openings defined in a surface of the polishing layer, voids formed in the polishing layer below the surface, pore-forming features comprising the sacrificial material composition, or combinations thereof. The method as claimed in item 13, wherein the surfactant comprises polybutylphenol, nonylphenol, 2-methyl-4-trioctylphenol, 4,6-ditributyl-2-methylphenol or at least one of its combinations. The method of claim 13, wherein a concentration of the surfactant in the prepolymer composition is about 1 wt% or less. The method of claim 13, wherein the surfactant increases a hydrophobicity of the dispensed droplets of the prepolymer composition. A polishing pad comprising: A plurality of polishing elements, each comprising: an individual surface forming part of a polishing surface of the polishing pad, and One or more side walls extending downwardly from the respective surface to define a plurality of channels disposed between the polishing elements, wherein: a plurality of hole features formed in each of the polishing elements, each of the polishing elements is formed from a prepolymer composition and a sacrificial material composition, a volume of the hole feature space of an individual of the plurality of hole features comprises at least 50% of a volume of the sacrificial material composition dispensed to form the corresponding hole feature, and The plurality of pore features include openings defined in the polishing surface, voids formed in the polishing element below the polishing surface, pore-forming features comprising the sacrificial material composition, or combinations thereof. The polishing pad of claim 17, wherein the prepolymer composition includes a multifunctional acrylate component. The polishing pad of claim 17, wherein the prepolymer composition includes a surfactant. The polishing pad as described in claim 17, wherein: A concentration of one polyethylene glycol monoacrylate component in the sacrificial material composition is about 30 wt% or greater, A concentration of a polyethylene glycol diacrylate component in the sacrificial material composition is about 10 wt% or less, and A concentration of a polyethylene glycol component in the sacrificial material composition is about 40 wt% or less.

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