Chemical mechanical polishing composition for polishing lithium tantalate and / or lithium niobate substrate and polishing method thereof

Abstract

The invention provides a chemical mechanical polishing composition for polishing a lithium tantalate and / or lithium niobate substrate and a polishing method thereof. Wherein the chemical mechanical polishing composition comprises silicon oxide abrasive particles, a protein or a peptide derived therefrom, and a polishing aid, and wherein the protein or the peptide derived therefrom can increase the stability of the composition during polishing, thereby reducing precipitation of the chemical mechanical polishing composition during a polishing cycle.

Description

Technical Field

[0001] This application relates to the field of chemical technology, and in particular to a chemical mechanical polishing composition and polishing method for polishing lithium tantalate and / or lithium niobate substrates. Background Technology

[0002] Lithium tantalate and / or lithium niobate, as single-crystal oxide materials, are widely used in high-frequency electronic components, optical equipment, and sensors. Their excellent piezoelectricity and stability make them the preferred materials for many high-tech applications. To obtain high-quality lithium tantalate and / or lithium niobate materials, their surfaces need to be polished.

[0003] However, during the fine grinding of lithium tantalate and / or lithium niobate, the silica abrasive particles in the polishing slurry easily combine with themselves or reaction products to form precipitates during chemical mechanical removal. This not only impairs surface quality and dimensional accuracy but may also cause problems such as chemical contamination and stress concentration, thereby weakening material properties and reducing product reliability and service life. Therefore, reducing silica precipitation in the polishing slurry is crucial. Summary of the Invention

[0004] This application provides a chemical mechanical polishing composition and a polishing method thereof for polishing lithium tantalate and / or lithium niobate substrates. The chemical mechanical polishing composition includes a protein or a derivative thereof, thereby increasing the stability of the composition during the polishing process.

[0005] To achieve the above objectives, the embodiments of this application adopt the following technical solutions:

[0006] In a first aspect, embodiments of this application provide a chemical mechanical polishing composition for polishing lithium tantalate and / or lithium niobate substrates, comprising silicon oxide abrasive particles, a protein or its derivative peptide, and a polishing aid, wherein the protein or its derivative peptide can increase the stability of the composition during the polishing process.

[0007] According to some embodiments of this application, the protein or its derived peptides include at least one of collagen or collagen peptides.

[0008] According to some embodiments of this application, the molecular weight of the protein or its derived peptide is 2kDa-20kDa.

[0009] According to some embodiments of this application, the composition includes 0.001 wt% to 1 wt% of the protein or its derived peptides.

[0010] According to some embodiments of this application, the composition also includes polysaccharides.

[0011] According to some embodiments of this application, the polysaccharide includes at least one of alginic acid, alginate, pectic acid, agar, xanthan gum, and chitosan.

[0012] According to some embodiments of this application, the composition has a pH value of 7-12.

[0013] According to some embodiments of this application, the polishing aid includes a chelating agent, which includes at least one of dicarboxylic acid, tricarboxylic acid, polycarboxylic acid, or polycarboxylic acid.

[0014] According to some embodiments of this application, the polishing aid includes a removal rate enhancer, which includes one of a potassium salt, a sodium salt, or an ammonium salt.

[0015] In a second aspect, embodiments of this application provide a polishing method for lithium tantalate and / or lithium niobate substrates, the method utilizing a composition as described in any one of the first aspects above to polish the lithium tantalate and / or lithium niobate substrates.

[0016] In summary, this application provides a chemical mechanical polishing (CMP) composition and a polishing method thereof for polishing lithium tantalate and / or lithium niobate substrates and thin films. The CMP composition comprises silica abrasive particles, a protein or its derivative peptides, and a polishing aid. The protein or its derivative peptides can increase the stability of the composition during polishing, thereby reducing precipitation of the CMP composition during cycling. Detailed Implementation

[0017] The following description provides specific application scenarios and requirements for this specification, intended to enable those skilled in the art to make and use the contents of this specification. Various partial modifications to the disclosed embodiments will be apparent to those skilled in the art, and the general principles defined herein can be applied to other embodiments and applications without departing from the spirit and scope of this specification. Therefore, this specification is not limited to the embodiments shown, but rather to the widest scope consistent with the claims.

[0018] The terminology used herein is for the purpose of describing particular exemplary embodiments only and is not restrictive. For example, unless the context clearly indicates otherwise, the singular forms “a,” “an,” and “the” used herein may also include the plural forms. When used in this specification, the terms “comprising,” “including,” and / or “containing” mean that the associated integers, steps, operations, elements, and / or components are present, but do not exclude the presence of one or more other features, integers, steps, operations, elements, components, and / or groups, or that other features, integers, steps, operations, elements, components, and / or groups may be added to the system / method.

[0019] In this application, "X includes at least one of A, B, or C" means that X includes at least A, or X includes at least B, or X includes at least C. That is, X can include any combination of A, B, and C, or any combination of A, B, and C, as well as other possible content / elements. The arbitrary combination of A, B, and C can be A, B, C, AB, AC, BC, or ABC.

[0020] Considering the following description, these and other features of this specification, as well as the operation and function of related structural elements, and the economy of assembly and manufacture of components, can be significantly improved. This description also includes all figures and text in the accompanying drawings, all of which form part of this specification. However, it should be clearly understood that the drawings are for illustrative and descriptive purposes only and are not intended to limit the scope of this specification. It should also be understood that the drawings are not drawn to scale.

[0021] Lithium tantalate and / or lithium niobate are renowned for their superior piezoelectric, ferroelectric, optoelectronic, thermoelectric, and electroacoustic properties, making them indispensable in high-frequency electronic devices, nonlinear optics, and laser technology. As hard and brittle materials, lithium tantalate and / or lithium niobate exhibit good chemical stability, requiring specialized processes and techniques for polishing. To maintain a high-quality surface finish and prevent internal damage, the dispersion of abrasive particles in the polishing slurry must be controlled during polishing to prevent abrasive particle aggregation and sedimentation, which would compromise surface quality and affect the final product's excellent optical transparency and electrical properties.

[0022] In view of this, some embodiments of this application provide a chemical mechanical polishing composition (hereinafter referred to as the composition) for polishing lithium tantalate and / or lithium niobate substrates and a polishing method thereof. Proteins and their derived peptides are introduced into the composition. The proteins and their derived peptides can adsorb onto the surface of silica abrasive particles by forming specific interactions with the surface of the silica abrasive particles through their specific amino acid sequences, such as hydrogen bonding, electrostatic interactions, or hydrophobic interactions. This adsorption forms a stable protective layer that prevents direct contact and aggregation between silica abrasive particles through steric hindrance and / or electrostatic repulsion. Furthermore, the high water solubility and good dispersibility of the proteins and their derived peptides ensure that the silica abrasive particles can be uniformly distributed in the polishing solution, maintaining a stable dispersion state for a long time, thereby effectively preventing the aggregation of silica abrasive particles.

[0023] Before describing the specific embodiments of this specification, the application scenarios of this specification will be introduced as follows.

[0024] The compositions provided in this specification can be used for polishing lithium tantalate and / or lithium niobate substrates and thin films, including but not limited to those for lithium tantalate and / or lithium niobate. Specifically, the compositions provided in this specification can be used for polishing lithium tantalate and / or lithium niobate substrates of various crystal forms, such as Z-cut, X-cut, Y-cut, rotary Y-cut, and double rotary cut. The compositions provided in this specification can be used for polishing lithium tantalate and / or lithium niobate substrates of various shapes, such as round, square, strip, irregular, and sheet-like shapes.

[0025] The composition includes silica abrasive grains. These silica abrasive grains provide a mechanical abrasive action, removing minute protrusions and uneven areas on the surface of the silicon carbide substrate through physical friction. The silica abrasive grains are silica dioxide abrasive grains. These silica abrasive grains are colloidal silica abrasive grains, i.e., silica prepared by hydrolysis or sol-gel methods. The colloidal silica can be obtained by wet processes, such as precipitation (precipitated silica), polycondensation, or similar processes.

[0026] In the CMP process, the composition includes 15-45 wt% silica abrasive particles. In some embodiments, the weight percentage of silica abrasive particles in the composition is between 20-40 wt%. In some embodiments, the weight percentage of silica abrasive particles in the composition is between 15-25 wt%. In some embodiments, the weight percentage of silica abrasive particles in the composition is between 30-45 wt%. Further, the weight percentage of silica abrasive particles in the composition can be selected as 15 wt%-16 wt%, 16 wt%-17 wt%, 17 wt%-18 wt%, 18 wt%-19 wt%, 19 wt%-20 wt%, 20 wt%-21 wt%, 21 wt%-22 wt%, 22 wt%-23 wt%, 23 wt%-24 wt%, 24 wt%-25 wt%, 25 wt%-26 wt%, 26 wt%-27 wt%, 27 wt%-28 wt%, 28 wt%-29 wt%. Between 29wt%-30wt%, 30wt%-31wt%, 31wt%-32wt%, 32wt%-33wt%, 33wt%-34wt%, 34wt%-35wt%, 35wt%-36wt%, 36wt%-37wt%, 37wt%-38wt%, 38wt%-39wt%, 39wt%-40wt%, 40wt%-41wt%, 41wt%-42wt%, 42wt%-43wt%, 43wt%-44wt%, and 44wt%-45wt%.

[0027] Silica abrasive grains have a spherical morphology. This spherical morphology is not limited to a perfect sphere, i.e., any circular shape without substantial edges and vertices (corners), such as spherical, elliptical, or grape-like structures. The spherical morphology can be determined by those skilled in the art, for example, using images from transmission electron microscopy (TEM) or scanning electron microscopy (SEM).

[0028] The particle size distribution of silica abrasive grains affects their precipitation in the composition. The particle size span of silica abrasive grains can be described by the particle size span. The particle size span of silica abrasive grains refers to the value obtained by the formula (D90 - D10) / D50. It is understood that the particle size of silica abrasive grains can be obtained by dynamic light scattering measurement (e.g., using a Malvern Mastersizer from Malvern Instruments). Here, D10 is the particle size of 10 vol% silica abrasive grains smaller than this value. D50 is the particle size of 50 vol% silica abrasive grains smaller than this value. D90 is the particle size of 90 vol% silica abrasive grains smaller than this value. It is understood that D90, D10, and D50 can be measured by dynamic light scattering as described above. It should be noted that the particle size span, z-average particle size, D10, D50, and D90 described herein refer to the particle size of the silica abrasive particles in the composition.

[0029] In some embodiments, the particle size range of the silicon oxide abrasive grains is 0.6-2. In some embodiments, the particle size range of the silicon oxide abrasive grains is 0.8-1.3. In some embodiments, the particle size range of the silicon oxide abrasive grains is 1.4-2.0. Further, the particle size range of the silicon oxide abrasive grains is 0.6, 0.7, 0.8, 0.9, 1.0, 1.1, 1.2, 1.3, ...

[0030] 1.4, 1.5, 1.6, 1.7, 1.8, 1.9 or 2, and particle size ranges between any of the above values.

[0031] The z-average particle size can be further measured by dynamic light scattering, for example using a Zetasizer Nano ZSE (Malvern Instruments Ltd.); the z-average particle size refers to the intensity-weighted average hydrodynamic size of a particle ensemble as measured by dynamic light scattering (e.g., using a Zetasizer Nano ZSE (Malvern Instruments Ltd.)). Specifically, the silica abrasive particles have a z-average particle size of 50-200 nm as measured by dynamic light scattering. In some embodiments, the silica abrasive particles have a z-average particle size of 60-150 nm as measured by dynamic light scattering. In some embodiments, the silica abrasive particles have a z-average particle size of 70-100 nm as measured by dynamic light scattering. In some embodiments, the silica abrasive particles have a z-average particle size of 100-130 nm as measured by dynamic light scattering. Further, the silica abrasive particles have a z-average particle size of 50 nm-60 nm, 60 nm-70 nm, 70 nm-80 nm, or 80 nm-80 nm as measured by dynamic light scattering. The Z-average particle size is between 5nm, 85nm-90nm, 90nm-95nm, 95nm-100nm, 100nm-105nm, 105nm-110nm, 110nm-115nm, 115nm-120nm, 120nm-125nm, 125nm-130nm, 130nm-135nm, 135nm-140nm, 140nm-150nm, 150nm-160nm, 160nm-170nm, 180nm-190nm, or 190nm-200nm. It should be noted that the Z-average particle size described here refers to the particle size of the silica abrasive particles in the composition.

[0032] Further, the silicon oxide abrasive grains have a D10 in the dynamic light scattering measurement range of 10-90 nm. In some embodiments, the silicon oxide abrasive grains have a D10 in the dynamic light scattering measurement range of 20-80 nm. In some embodiments, the silicon oxide abrasive grains have a D10 in the dynamic light scattering measurement range of 30-70 nm. Even further, the silicon oxide abrasive grains have a D10 in the dynamic light scattering measurement range of 10 nm, 15 nm, 20 nm, 25 nm, 30 nm, 35 nm, 40 nm, 45 nm, 50 nm, 55 nm, 60 nm, 65 nm, 70 nm, 75 nm, 80 nm, 85 nm, or 90 nm.

[0033] Silica abrasive grains have a D50 in the dynamic light scattering measurement range of 30-120 nm. In some embodiments, silica abrasive grains have a D50 in the dynamic light scattering measurement range of 40-110 nm. In some embodiments, silica abrasive grains have a D50 in the dynamic light scattering measurement range of 50-100 nm. In some embodiments, silica abrasive grains have a D50 in the dynamic light scattering measurement range of 50-90 nm. Furthermore, the silicon oxide abrasive grains have a D50 that is dynamically measured to be between 30nm-35nm, 35nm-40nm, 40nm-45nm, 45nm-50nm, 50nm-55nm, 55nm-60nm, 60nm-65nm, 65nm-70nm, 70nm-75nm, 75nm-80nm, 80nm-85nm, 85nm-90nm, 90nm-95nm, 95nm-100nm, 100nm-105nm, 105nm-110nm, 110nm-115nm, or 115nm-120nm.

[0034] Silica abrasive grains have a D90 in the dynamic light scattering measurement range of 80-240 nm. In some embodiments, silica abrasive grains have a D90 in the dynamic light scattering measurement range of 90-230 nm. In some embodiments, silica abrasive grains have a D90 in the dynamic light scattering measurement range of 150-220 nm. In some embodiments, silica abrasive grains have a D90 in the dynamic light scattering measurement range of 160-210 nm. In some embodiments, silica abrasive grains have a D90 in the dynamic light scattering measurement range of 80-150 nm. In some embodiments, silica abrasive grains have a D90 in the dynamic light scattering measurement range of 90-130 nm. Furthermore, the silicon oxide abrasive grains have dynamic light scattering measurements of 80nm-90nm, 90nm-100nm, 100nm-110nm, 110nm-120nm, 120nm-130nm, 130nm-135nm, 135nm-140nm, 140nm-145nm, 145nm-150nm, 150nm-155nm, 155nm-160nm, and 160nm-165nm. D90 is available in the following ranges: 165nm-170nm, 170nm-175nm, 175nm-180nm, 180nm-185nm, 185nm-190nm, 190nm-195nm, 195nm-200nm, 200nm-205nm, 205nm-210nm, 210nm-215nm, 215nm-220nm, 220nm-225nm, or 225nm-230nm.

[0035] In some embodiments, the silica abrasive particles are a mixture of particles with different particle size ranges. The mixed abrasive particles can be a mixture of N silica abrasive particles with different particle size ranges. Here, N is an integer greater than 2, such as 2, 3, 4, 5, etc. When the silica abrasive particles are a mixture of N silica abrasive particles with different particle size ranges, the Z-average particle size, D10, D50, and D90 of the mixed abrasive particles are the same as those in the silica abrasive particles in the above embodiments, and will not be described again here.

[0036] It should be noted that the silica abrasive grains may contain impurities. These impurities originate from the raw materials or processes used to prepare the abrasive grains. These impurities can be considered as not being part of the mixed silica abrasive grains; that is, they are not added to the composition as a single component. This means that the impurities are not added by weight.

[0037] The silica abrasive grains are negatively charged. The charge refers to the zeta potential, which can be measured, for example, by a Mastersizer S (Malvern Instruments). As those skilled in the art know, the zeta potential is the potential at the interface between the moving fluid within the composition and the fluid-stabilized layer attached to the abrasive grains dispersed in the composition. The higher the absolute value of the zeta potential, the stronger the electrostatic repulsion between particles, and therefore the higher the dispersion stability of the particles in the composition. In this embodiment, the silica abrasive grains have a zeta potential of at least -10 mV in the composition at a pH of 8.5 to 9.5. Further, the silica abrasive grains have a zeta potential of at least -10 mV, -15 mV, -20 mV, -25 mV, 30 mV, -35 mV, or -40 mV, and between any of these values, in the composition at a pH of 8.5 to 9.5.

[0038] The composition further includes one or more chemical additives. These chemical additives can interact with abrasive particles and / or with the substrate and / or with the polishing pad during the CMP process. This interaction can be based on, for example, hydrogen bonds, van der Waals forces, electrostatic forces, etc. The chemical additives can be any component suitable for use as, for example, a removal rate promoter, a polishing rate inhibitor, a surfactant, a thickener, a regulator, a complexing agent, a chelating agent, a biocide, a dispersant, an oxidizing agent, a film-forming agent, an etching inhibitor, a catalyst, a terminating compound, a dissolution inhibitor, or a combination thereof.

[0039] The composition also includes a liquid carrier, proteins and their derived peptides, and polishing aids. The proteins and their derived peptides are capable of forming specific interactions with the surface of silica abrasive particles, such as hydrogen bonds, electrostatic interactions, or hydrophobic interactions, preventing direct contact and aggregation between silica abrasive particles. In some embodiments, the composition also includes polysaccharides.

[0040] The liquid carrier can contain other components of the composition besides the liquid carrier itself, such as proteins and their derived peptides, polishing aids, polysaccharides, etc., to suspend these components in the liquid carrier and allow them to contact the lithium tantalate and / or lithium niobate substrate for polishing. The liquid carrier can be an aqueous carrier, and can be any component suitable for suspending silica abrasive particles and chemical additives. The liquid carrier can be one of water, ethers (such as dioxane and tetrahydrofuran), and alcohols (such as methanol and ethanol), or a combination of water, ethers (such as dioxane and tetrahydrofuran), and alcohols (such as methanol and ethanol). When the liquid carrier is a combination of multiple components, the liquid carrier contains at least 50 wt% water, for example, the aqueous carrier contains 50 wt%, 70 wt%, 90 wt%, 95 wt%, or 99 wt% water. Further, the water is deionized water.

[0041] Proteins and their derived peptides are biological macromolecules or short-chain molecules formed by amino acid units linked by peptide bonds. Proteins and their derived peptides typically have large molecular weights and complex three-dimensional structures. When they adsorb onto the surface of silica abrasive particles, they form a thick protective film. This protective film prevents direct contact between silica abrasive particles through steric hindrance, reducing the possibility of silica abrasive particle aggregation and precipitation. Furthermore, proteins and their derived peptides contain many polar groups (such as carboxyl, amino, and hydroxyl groups), which can become charged under appropriate pH conditions. For example, in an alkaline environment, amino groups may protonate to form positive ions (-NH3). + These charged groups may form an electric double layer on the surface of silica abrasive grains, generating electrostatic repulsion and further preventing mutual attraction and aggregation between silica abrasive grains. In addition, hydrophilic groups (such as hydroxyl, carboxyl, and amino groups) in proteins and their derived peptides can form hydrogen bonds with water molecules, increasing the thickness of the hydrated layer. This hydration keeps the surface of silica abrasive grains highly hydrated, reducing van der Waals attraction between particles and effectively preventing precipitation.

[0042] The molecular weight of the protein and its derived peptides is 1 kDa-30 kDa. In some embodiments, the molecular weight of the protein and its derived peptides is 1.5 kDa-25 kDa. In some embodiments, the molecular weight of the protein and its derived peptides is 2 kDa-20 kDa. In some embodiments, the molecular weight of the protein and its derived peptides is 0.5 kDa-15 kDa. Further, the molecular weight of the protein and its derived peptides is between 1 kDa-5 kDa, 5 kDa-10 kDa, 10 kDa-15 kDa, 15 kDa-20 kDa, 20 kDa-25 kDa, or 25 kDa-30 kDa.

[0043] Proteins and their derived peptides include collagen and collagen peptides. Collagen has a unique triple-helix structure, consisting of three polypeptide chains (α chains) tightly wound together by hydrogen bonds. Each α chain consists of a repeating Gly-XY sequence, where Gly (glycine) is the smallest amino acid, and X and Y are typically Pro (proline) or Hydroxyproline. This structure gives collagen extremely high stability and mechanical strength. Collagen peptides are small peptide fragments extracted from collagen through enzymatic or chemical methods; for example, small peptide fragments consist of 2 to 20 amino acids. Collagen peptides retain a portion of the collagen's amino acid sequence, especially fragments rich in glycine, proline, and hydroxyproline. These peptide fragments can be linear or multibranched, which is not limited herein. This specification does not limit the number of amino acids in collagen peptides.

[0044] Proteins or derived peptides can be derived from any suitable source of an organism, such as animals, fungi, protozoa, bacteria, or archaea. In some embodiments, proteins or derived peptides may include fish peptides, whey peptides, casein peptides, silk peptides, pea peptides, almond peptides, oat peptides, elastin peptides, egg white peptides, snail peptides, chitosan peptides, corn peptides, pumpkin seed peptides, marine collagen peptides, milk-derived peptides, sesame peptides, lentil peptides, quinoa peptides, spirulina peptides, soybean peptides, rice peptides, eel peptides, keratin peptides, casein, and albumin. In some embodiments, proteins and their derived peptides also include at least one of soybean peptides, rice peptides, eel peptides, keratin peptides, casein, and albumin. It is understood that proteins and their derived peptides can exist in a variety of forms. These forms include, but are not limited to, whole protein molecules, proteins that have undergone various chemical or biological modifications, and peptides of any suitable size derived from protein hydrolysis.

[0045] When used, the composition comprises 0.001-3 wt% of protein and its derived peptides. In some embodiments, the composition comprises 0.005-2.5 wt% of protein and its derived peptides. In some embodiments, the composition comprises 0.01-2 wt% of protein and its derived peptides. In some embodiments, the composition comprises 0.05-1.5 wt% of protein and its derived peptides. Further, the composition comprises 0.001wt%-0.005wt%, 0.005wt%-0.01wt%, 0.01wt%-0.05wt%, 0.05wt%-0.1wt%, 0.1wt%-0.15wt%, 0.15wt%-0.2wt%, 0.2wt%-0.25wt%, 0.25wt%-0.3wt%, 0.3wt%-0.35wt%, 0.35wt%-0.4wt%, 0.4wt%-0.45wt%, 0.45wt%-0.5wt%, 0.5wt%-0.55wt%, 0.55wt%-0.6wt%, 0.6wt%-0.65wt%, and 0. Proteins and their derived peptides in the following proportions: 65wt%-0.7wt%, 0.7wt%-0.75wt%, 0.75wt%-0.8wt%, 0.8wt%-0.85wt%, 0.85wt%-0.9wt%, 0.9wt%-0.95wt%, 0.95wt%-1wt%, 1wt%-1.2wt%, 1.2wt%-1.4wt%, 1.4wt%-1.6wt%, 1.6wt%-1.8wt%, 1.8wt%-2wt%, 2wt%-2.2wt%, 2.2wt%-2.4wt%, 2.4wt%-2.6wt%, 2.6wt%-2.8wt%, or 2.8wt%-3wt%.

[0046] In some embodiments, the composition further includes polysaccharides. Polysaccharides are complex carbohydrates composed of multiple monosaccharide molecules linked by glycosidic bonds. Adding polysaccharides to the composition can increase the viscosity of the polishing slurry, thereby preventing the sedimentation of silica abrasive particles and maintaining a uniform dispersion. The types of polysaccharides can be varied, including, for example, at least one of cellulose, hemicellulose, starch, amylose, amylopectin, glycogen, dextran, guar gum, gum arabic, carrageenan, xanthan gum, pullulan, condensed polysaccharides, β-glucan, mannan, xylan, galactomannan, chondroitin sulfate, hyaluronic acid, fucoidan, laminaria, heparin, agarose, inulin, alginic acid, alginate, pectic acid, agar, xanthan gum, or chitosan. Further, the polysaccharide includes at least one of alginic acid, alginate, pectic acid, agar, xanthan gum, and chitosan.

[0047] When used, the composition comprises 0.0001-1 wt% polysaccharide. In some embodiments, the composition comprises 0.001-0.05 wt% polysaccharide. In some embodiments, the composition comprises 0.2-0.4 wt% polysaccharide. Further, the composition comprises 0.0001 wt%-0.001 wt%, 0.001 wt%-0.01 wt%, 0.01 wt%-0.05 wt%, 0.05 wt%-0.1 wt%, 0.1 wt%-0.15 wt%, 0.15 wt%-0.2 wt%, 0.2 wt%-0.25 wt%, 0.25 wt%-0.3 wt%, 0.3 wt%-0.35 wt%, 0.35 wt%-0.4 wt%, 0.4 wt%- Polysaccharides in the range of 0.45wt%, 0.45wt%-0.5wt%, 0.5wt%-0.55wt%, 0.55wt%-0.6wt%, 0.6wt%-0.65wt%, 0.65wt%-0.7wt%, 0.7wt%-0.75wt%, 0.75wt%-0.8wt%, 0.8wt%-0.85wt%, 0.85wt%-0.9wt%, 0.9wt%-0.95wt%, or 0.95wt%-1wt%.

[0048] Polishing aids include surfactants. In some embodiments, polishing aids also include chelating agents, pH adjusters, and removal rate enhancers.

[0049] Surfactants can help enhance stability, increase humidity, control optical defects, and reduce surface roughness and haze. Surfactants can be anionic or nonionic. Anionic surfactants can include at least one of carboxylates, sulfonates, sulfates, phosphates, phosphate esters, or phosphonates. Further, carboxylates can include sodium laurylate, sodium oleate, sodium stearate, potassium palmitate, sodium myristate, etc. Sulfonates can include triethanolamine dodecylbenzenesulfonate, sodium dodecylbenzenesulfonate, ammonium dodecylbenzenesulfonate, pentadecylbenzenesulfonic acid, calcium dodecylbenzenesulfonate, sodium xylenesulfonate, sodium isopropylbenzenesulfonate, sodium dioctyl sulfosuccinate, etc. Sulfates can include sodium dodecyl sulfate, sodium myristyl ether sulfate, sodium alkanol ether sulfate, sodium polyoxyethylene dodecyl ether sulfate, sodium polyoxyethylene nonylphenyl ether sulfate, etc. Phosphates can include sodium polyoxyethylene dodecyl phosphate, disodium monoalkyl phosphate, etc. Phosphates can include sodium polyoxyethylene nonylphenyl ether phosphate, lauryl phosphate, etc. Phosphonates may include dodecylphosphonic acid or hexadecylphosphonic acid, etc. Among many anionic surfactants, sulfonates are selected as surfactants in this specific embodiment.

[0050] Nonionic surfactants may include at least one of alkyl polyglucosides, fatty alcohol ethoxylates, polysorbates, dehydrated sorbates, polyethylene glycol, polyethylene glycol esters, fatty alkanolamides, ethoxylated amines, or ethoxylated amides. In a specific embodiment, the anionic surfactant is selected as a fatty alcohol ethoxylate. The fatty alcohol ethoxylate can be any suitable fatty alcohol ethoxylate. Specifically, the fatty alcohol ethoxylate includes at least one of cetyl polyethylene glycol ether, stearyl polyethylene glycol ether, alkanol polyethylene glycol ether, alkanol polyethylene glycol ether, or derivatives thereof. The alkyl group of the fatty alcohol ethoxylate can be any suitable alkyl group, such as methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, decyl, dodecyl, hexadecyl, or stearyl, etc.

[0051] When used, the composition includes 0.0001-0.1 wt% of a surfactant. In some embodiments, the composition includes 0.001-0.08 wt% of a surfactant. In some embodiments, the composition includes 0.005-0.05 wt% of a surfactant. In some embodiments, the composition includes 0.01-0.03 wt% of a surfactant. Further, the composition comprises 0.0001wt%-0.0005wt%, 0.0005wt%-0.001wt%, 0.001wt%-0.005wt%, 0.005wt%-0.01wt%, 0.01wt%-0.015wt%, 0.015wt%-0.02wt%, 0.02wt%-0.025wt%, 0.025wt%-0.03wt%, 0.03wt%-0.035wt%, 0.035wt%-0.04wt%, and 0.04wt%-0.04wt%. Surfactants in the following concentrations: 5 wt%, 0.045 wt% - 0.05 wt%, 0.05 wt% - 0.055 wt%, 0.055 wt% - 0.06 wt%, 0.06 wt% - 0.065 wt%, 0.065 wt% - 0.07 wt%, 0.07 wt% - 0.075 wt%, 0.075 wt% - 0.08 wt%, 0.08 wt% - 0.085 wt%, 0.085 wt% - 0.09 wt%, 0.09 wt% - 0.095 wt%, and 0.095 wt% - 0.1 wt%.

[0052] Chelating agents can bind to metal ions that may form during CMP treatment. Depending on the substrate being polished, chelating agents can improve material removal rates during polishing. The chelating agent includes at least one of polycarboxylic acids, dicarboxylic acids, or tricarboxylic acids. Further, polycarboxylic acids include polyacrylic acid (PAA), polymethacrylic acid (PMAA), and polymaleic acid (PMA), and combinations thereof. Dicarboxylic acids include oxalic acid, malonic acid, succinic acid, maleic acid, phthalic acid, tartaric acid, aspartic acid, glutamic acid, and combinations thereof. Tricarboxylic acids include citric acid, butanetetracarboxylic acid, and combinations thereof. In some embodiments, the chelating agent includes aminopolycarboxylic acids, aminophosphonic acids, and combinations thereof. The aminopolycarboxylic acids include ethylenediaminetetraacetic acid (EDTA), hydroxyethylethylenediaminetriacetic acid (HEDTA), triethylenediaminetetraacetic acid (EGTA), diethylenetriaminepentaacetic acid (DTPA), diaminohydroxypropanetetraacetic acid (DTPA-OH), triethylenetetraaminehexaacetic acid (TTHA), iminodiacetic acid (IDA), nitrotriacetic acid (NTA), bis(aminophenoxyethanetetraacetic acid) (BAPTA), nicotinamide, ethylenediaminedihydroxyphenylacetic acid (EDDHA), and combinations thereof. The aminophosphonic acids include ethylenediaminetetra(methylenephosphonic acid) (EDTMP), aminotri(methylenephosphonic acid), diethylenetriaminepenta(methylenephosphonic acid) (DTPMP), and combinations thereof. In a preferred embodiment, the chelating agent includes at least one selected from EDTA, oxalic acid, malonic acid, gluconic acid, malic acid, or citric acid.

[0053] When used, the composition includes 0.01-5 wt% of a chelating agent. In some embodiments, the composition includes 0.01-3 wt% of a chelating agent. In some embodiments, the composition includes 0.1-2 wt% of a chelating agent. Further, the composition includes a chelating agent in amounts between 0.01 wt%-0.1 wt%, 0.1 wt%-0.5 wt%, 0.5 wt%-1 wt%, 1 wt%-1.5 wt%, 1.5 wt%-2 wt%, 2 wt%-2.5 wt%, 2.5 wt%-3 wt%, 3 wt%-3.5 wt%, 3.5 wt%-4 wt%, 4 wt%-4.5 wt%, and 4.5 wt%-5 wt%.

[0054] In some embodiments, the polishing aid further includes a pH adjuster. The pH adjuster helps to bring the composition to a suitable pH. The pH adjuster also acts as an etchant and is used to assist in polishing silicon-containing substrates. The pH adjuster can be a base or a salt thereof, specifically an organic base, an inorganic base, or a combination thereof. The organic base can be a quaternary ammonium hydroxide (e.g., tetramethylammonium hydroxide (TMAH), tetraethylammonium hydroxide (TEAH), tetrapropylammonium hydroxide (TPAH), tetrabutylammonium hydroxide (TBAH)), piperazine, pyrazine, guanidine (e.g., guanidine carbonate, guanidine hydrochloride, arginine, creatine), imidazole, triazole, methylamine, ethylamine, dimethylamine, diethylamine, trimethylamine, triethylamine, ethylenediamine, monoethanolamine, diethanolamine, aminoethylethanolamine, linear primary diamines (e.g., butane-1,4-diamine, pentane-1,5-diamine, hexane-1,6-diamine, heptane-1,7-diamine, octane-1,8-diamine) or a combination thereof. Inorganic bases include alkali metal hydroxides (e.g., potassium hydroxide, sodium hydroxide, lithium hydroxide), alkaline earth metal hydroxides (e.g., magnesium hydroxide, calcium hydroxide, beryllium hydroxide), alkali metal carbonates (e.g., potassium carbonate, potassium bicarbonate, sodium carbonate, sodium bicarbonate, lithium bicarbonate), alkaline earth metal carbonates (e.g., magnesium carbonate, calcium carbonate, beryllium carbonate), alkali metal phosphates (e.g., tripotassium phosphate, trisodium phosphate, dipotassium phosphate, disodium phosphate), alkaline earth metal phosphates (e.g., magnesium phosphate, calcium phosphate, beryllium phosphate), ammonium carbonate, ammonium bicarbonate, ammonium hydroxide, ammonia, or combinations thereof. Preferably, the pH adjuster is an inorganic base. In some embodiments, the pH adjuster is selected from alkali metal hydroxides, alkaline earth metal hydroxides, ammonium hydroxide, ammonium carbonate, ammonia, and combinations thereof. Adding a pH adjuster can increase the material removal rate of the silicon carbide substrate.

[0055] pH adjusters allow the composition to be maintained within a specific pH range. By controlling the pH value, the pH adjuster can influence the removal rate of the silicon carbide substrate. The specific pH range can be 7-12, meaning the composition has a pH value of 7-12. In some embodiments, the composition has a pH value of 8-10. In some embodiments, the composition has a pH value of 8.5-9.5. Further, the composition has a pH value between 7-7.5, 7.5-8, 8-8.5, 8.5-9, 9-9.5, 9.5-10, 10.5-11, 11-11.5, or 11.5-12.

[0056] In some embodiments, the polishing aid further includes a removal rate enhancer. The removal rate enhancer can be used to increase the removal rate of silica abrasive particles from the surface of lithium tantalate and / or lithium niobate substrates. The removal rate enhancer may include at least one of potassium, sodium, or ammonium salts. Potassium salts include potassium hydroxide, tripotassium ethylenediaminetetraacetate (EDTA), potassium nitrate, potassium carbonate, potassium bicarbonate, potassium phosphate, etc. Sodium salts include sodium hydroxide, sodium nitrate, etc. Ammonium salts include ammonium hydroxide, ammonium nitrate, ammonium citrate, ammonium oxalate, ammonium succinate, etc. In some embodiments, the removal rate enhancer further includes cerium hydroxide and cerium nitrate. In preferred embodiments, the removal rate enhancer is potassium hydroxide, tripotassium ethylenediaminetetraacetate (EDTA tripotassium), ammonium citrate, or ammonium succinate.

[0057] In some embodiments, the composition comprises 0.005-5 wt% of a removal rate enhancer. In some embodiments, the composition comprises 0.08-4.5 wt% of a removal rate enhancer. In some embodiments, the composition comprises 0.1-2 wt% of a removal rate enhancer. Further, the composition comprises a removal rate enhancer in amounts between 0.005 wt%-0.05 wt%, 0.05 wt%-0.1 wt%, 0.1 wt%-0.5 wt%, 0.5 wt%-1 wt%, 1 wt%-1.5 wt%, 1.5 wt%-2 wt%, 2 wt%-2.5 wt%, 2.5 wt%-3 wt%, 3 wt%-3.5 wt%, 3.5 wt%-4 wt%, 4 wt%-4.5 wt%, and 4.5 wt%-5 wt%.

[0058] Another aspect of the present invention provides a polishing method for lithium tantalate and / or lithium niobate substrates, the method comprising the steps of: (a) providing the above-described chemical mechanical polishing composition; (b) contacting the lithium tantalate and / or lithium niobate substrate with the chemical mechanical polishing composition and a polishing pad; (c) moving the polishing pad relative to the lithium tantalate and / or lithium niobate substrate, wherein the chemical mechanical polishing composition is located in the middle therein; and (d) removing at least a portion of the lithium tantalate and / or lithium niobate substrate. The method may optionally include other steps.

[0059] The silica abrasive grains and the aforementioned features of the silica abrasive grains described in this application can be obtained through methods well known to those skilled in the art. In specific embodiments, colloidal silica particles can be prepared by polycondensation, for example, by condensing Si(OH)4 to form spherical particles. Si(OH)4 can be obtained by hydrolysis of alkoxysilanes or acidification of aqueous silicate solutions. Colloidal silica abrasive grains can also be prepared by precipitation from an acidic solution containing sodium silicate and sulfuric acid. Colloidal silica abrasive grains can also be purchased commercially from companies such as Bayer, DuPont, Fuso Chemical Company, Nalco, and Nissan Chemical.

[0060] The aforementioned silica abrasive and chemical additives can be added to the liquid carrier in any order and in appropriate amounts to achieve the desired concentration, thereby preparing the composition. The silica abrasive and chemical additives can be mixed and stirred in the liquid carrier. The silica abrasive and chemical additives can be added before use or at any time during the CMP process (e.g., one month, one day, one hour, or one minute).

[0061] The above-described compositions can be provided as a single-part system, a two-part system, or a multi-part system. For example, as a two-part system, the first part may contain silica abrasive particles and one or more chemical additives, and the second part may contain a first salt, a second salt, a catalyst, an oxidant, a pH adjuster, a buffer, a polymer, a surfactant, etc. The first and second parts can be combined at any time before or during the CMP process (e.g., one month, one day, one hour, or one minute), for example, when using a polishing apparatus with multiple supply paths for the CMP composition.

[0062] This invention also relates to the use of the above-described compositions of this invention. The compositions of this invention are used for chemical mechanical polishing (CMP) of lithium tantalate and / or lithium niobate substrates. As known to those skilled in the art, CMP refers to: within a CMP apparatus, a substrate is positioned in contact with a polishing pad and a CMP composition situated therebetween, the polishing pad moving relative to the substrate to remove a portion of the substrate.

[0063] The following are specific embodiments of the compositions designed based on the above content. It should be clarified that the following embodiments are merely illustrative of the compositions and polishing methods disclosed above, and the specific implementation methods and parameters used are only one or more of the numerous parameters and methods described above. Those skilled in the art can use other parameters to perform electrochemical mechanical polishing according to the methods described above without departing from the core spirit of the application.

[0064] In the following examples, a 4-inch diameter circular single-crystal lithium tantalate wafer was polished for 90 minutes using a Suba 600 polishing pad and a ZD380 polishing machine (Dongguan Zhongyan Grinding and Polishing Machinery Co., Ltd.) at a polishing disc speed of 60 rpm, a polishing head speed of 35 rpm, and a downforce of 20 kgf, using all the compositions (slurry recirculation, without adding additional slurry during recirculation), at a slurry flow rate of 50 ml / min. The weight of the lithium tantalate wafer before and after polishing was measured using an electronic balance, and the removal rate was calculated based on the weight difference.

[0065] Measurement of sedimentation during recycling: A tank containing slurry flows through a pipe onto the polishing disc of a polishing machine for polishing. The slurry is recovered during polishing and returned to the tank through a pipe. The returned slurry is filtered through a 200-mesh cloth. After polishing, solid sediment remains on the filter cloth. The filter cloth is carefully removed from the polishing tool and gently washed with deionized water, without removing the sediment. The solid sediment on the filter cloth is placed in an oven at 80°C for 16 hours. The solid sediment is removed from the filter cloth, and the weight of the sediment is measured. The weight of the sediment is shown as a relative weight in the table below.

[0066] Example 1

[0067] Compositions E1-E3 contained 40 wt% silica, 0.3 wt% EDTA, 0.1% ammonium oxalate, and 80 ppm Triton X-100. The pH was adjusted to 8.5 with KOH. As shown in Table 1, Example E3 also contained xanthan gum, and Examples E2 and E3 additionally contained fish skin collagen peptides with a molecular weight of 1700D (purchased from Hainan Yuantai Biotechnology Co., Ltd.). Table 1 shows the relative weight of the precipitated solids relative to Example E1.

[0068] Table 1

[0069] serial number polysaccharides peptides Relative weight of precipitated solids E1 - - 100％ E2 - 0.1wt% Collagen Peptides 31％ E3 0.02wt% xanthan gum 0.08wt% Collagen Peptides 69％

[0070] Conclusion: Adding collagen to the composition can reduce the precipitation during recycling.

[0071] In summary, this application provides a chemical mechanical polishing (CMP) composition and a polishing method thereof for polishing lithium tantalate and / or lithium niobate substrates. The CMP composition comprises silica abrasive particles, a protein or its derivative peptides, and a polishing aid. The protein or its derivative peptides increase the stability of the composition during polishing, thereby reducing precipitation of the CMP composition during cycling.

[0072] The foregoing has described specific embodiments of this specification. Other embodiments are within the scope of the appended claims. In some cases, the actions or steps recited in the claims may be performed in a different order than that shown in the embodiments and may still achieve the desired result. Furthermore, the processes depicted in the drawings do not necessarily require a specific or sequential order to achieve the desired result. In some embodiments, multitasking and parallel processing are possible or may be advantageous.

[0073] In summary, after reading this detailed disclosure, those skilled in the art will understand that the foregoing detailed disclosure may be presented by way of example only and may not be restrictive. Although not explicitly stated herein, those skilled in the art will understand that this specification requires various reasonable changes, improvements, and modifications to the embodiments. These changes, improvements, and modifications are intended to be made by this specification and are within the spirit and scope of the exemplary embodiments described herein.

[0074] Furthermore, certain terms in this specification have been used to describe embodiments of this specification. For example, "an embodiment," "an embodiment," and / or "some embodiments" mean that a particular feature, structure, or characteristic described in connection with that embodiment may be included in at least one embodiment of this specification. Therefore, it is to be emphasized and understood that two or more references to "an embodiment" or "an embodiment" or "alternative embodiment" in various parts of this specification do not necessarily refer to the same embodiment. Moreover, specific features, structures, or characteristics may be suitably combined in one or more embodiments of this specification.

[0075] It should be understood that in the foregoing description of the embodiments in this specification, various features are combined in a single embodiment, drawing, or description for the purpose of simplifying the description and to aid in understanding a feature. However, this does not mean that the combination of these features is necessary, and those skilled in the art may extract some features as individual embodiments when reading this specification. That is, the embodiments in this specification can also be understood as an integration of multiple sub-embodiments. It is also valid when each sub-embodiment contains fewer than all the features of a single foregoing disclosed embodiment.

[0076] Every patent, patent application, publication of a patent application, and other material, such as articles, books, specifications, publications, documents, and literature (excluding any related historical examination documents), cited in this disclosure is incorporated herein for all purposes, including, for example, in the specification and claims of this disclosure. However, in the event of any inconsistency or conflict between the descriptions, definitions, and / or terms used in the foregoing and those used in this disclosure, the descriptions, definitions, and / or terms used in this disclosure shall prevail.

[0077] Finally, it should be understood that the embodiments disclosed herein are illustrative of the principles of the embodiments described in this specification. Other modified embodiments are also within the scope of this specification. Therefore, the embodiments disclosed in this specification are merely examples and not limitations. Those skilled in the art can implement the applications described in this specification using alternative configurations based on the embodiments in this specification. Therefore, the embodiments in this specification are not limited to the embodiments precisely described in the applications.

Claims

1. A chemical mechanical polishing composition for polishing lithium tantalate and / or lithium niobate substrates, characterized in that, The composition includes silica abrasive particles, proteins or their derivative peptides, and polishing aids, wherein the proteins or their derivative peptides can increase the stability of the composition during the polishing process.

2. The composition according to claim 1, characterized in that, The protein or its derived peptides include at least one of collagen or collagen peptides.

3. The composition according to claim 1, characterized in that, The molecular weight of the protein or its derived peptide is 2kDa-20kDa.

4. The composition according to claim 1, characterized in that, The composition comprises 0.001 wt% to 1 wt% of the protein or its derivative peptides.

5. The composition according to claim 1, characterized in that, The composition also includes polysaccharides.

6. The composition according to claim 5, characterized in that, The polysaccharide includes at least one of alginic acid, alginate, pectic acid, agar, xanthan gum, and chitosan.

7. The composition according to claim 1, characterized in that, The composition has a pH value of 7-12.

8. The composition according to claim 1, characterized in that, The polishing aid includes a chelating agent, which includes at least one of dicarboxylic acid, tricarboxylic acid, or polycarboxylic acid.

9. The composition according to claim 8, characterized in that, The polishing aid includes a removal rate enhancer, which includes one of potassium salt, sodium salt, or ammonium salt.

10. A polishing method for lithium tantalate and / or lithium niobate substrates, characterized in that, The method utilizes the composition as described in any one of claims 1-9 to polish lithium tantalate and / or lithium niobate substrates.