Method for selective chemical mechanical polishing of cobalt, zirconium oxide, polysilicon and silicon dioxide films

Abstract

A method for chemical mechanical polishing a substrate containing cobalt, zirconium oxide, polysilicon and silicon dioxide, wherein the removal rates of cobalt, zirconium and polysilicon are selectively preferential to silicon dioxide. The chemical mechanical polishing composition comprises water, a benzyl trialkyl quaternary ammonium compound, a cobalt chelating agent, a corrosion inhibitor, a colloidal silica abrasive, optionally a biocide and optionally a pH adjuster, and the pH is greater than 7, and the chemical mechanical polishing composition does not contain an oxidizing agent.

Description

Technical Field

[0001] The present invention relates to a method for selectively chemically mechanically polishing cobalt, zirconium oxide, polysilicon and silicon dioxide films using a chemical mechanical polishing composition, the chemical mechanical polishing composition comprising water, a benzyl trialkyl quaternary ammonium compound, a cobalt chelating agent, a corrosion inhibitor, a colloidal silica abrasive, optionally a biocide and optionally a pH adjuster, and the pH is greater than 7, and the chemical mechanical polishing composition does not contain an oxidizing agent. More specifically, the present invention relates to a method for selectively chemically polishing cobalt, zirconium oxide, polysilicon and silicon dioxide films using a chemical mechanical polishing composition, the chemical mechanical polishing composition comprising water, a benzyl trialkyl quaternary ammonium compound, a cobalt chelating agent, a corrosion inhibitor, a colloidal silica abrasive, optionally a biocide and optionally a pH adjuster, and the pH is greater than 7, and the chemical mechanical polishing composition does not contain an oxidizing agent, wherein the removal rate of cobalt, zirconium oxide, and polysilicon is selectively preferential to silicon dioxide. Background Art

[0002] In the manufacture of integrated circuits and other electronic devices, multiple layers of conductive, semiconductive, and dielectric materials are deposited on or removed from the surface of a semiconductor wafer. Thin layers of conductive, semiconductive, and dielectric materials can be deposited by several deposition techniques. Common deposition techniques in modern processing include physical vapor deposition (PVD) (also known as sputtering), chemical vapor deposition (CVD), plasma enhanced chemical vapor deposition (PECVD), and electrochemical plating (ECP).

[0003] As material layers are deposited and removed in sequence, the uppermost surface of the wafer becomes non-planar. Because subsequent semiconductor processing (e.g., metallization) requires the wafer to have a flat surface, the wafer needs to be planarized. Planarization can be used to remove unwanted surface topography and surface defects, such as rough surfaces, agglomerated materials, lattice damage, scratches, and contaminated layers or materials.

[0004] Chemical mechanical planarization, or chemical mechanical polishing (CMP), is a common technique for planarizing substrates such as semiconductor wafers. In conventional CMP, a wafer is mounted on a carriage assembly and positioned to contact a polishing pad in a CMP apparatus. The carriage assembly provides a controllable pressure to the wafer, thereby pressing the wafer against the polishing pad. The pad is moved (e.g., rotated) relative to the wafer by an external driving force. At the same time, a polishing composition ("slurry") or other polishing liquid is provided between the wafer and the polishing pad. Therefore, the wafer surface is polished and made planar by the chemical and mechanical action of the pad surface and the slurry. However, CMP includes great difficulties. Each type of material requires a unique polishing composition, a properly designed polishing pad, an optimized process setting for both polishing and post-CMP cleaning, and other factors that must be individually customized for the application of a given material for polishing.

[0005] In advanced logic nodes ≤10nm, cobalt metal replaces the tungsten plugs that connect transistor gates to the back-end of line (BEOL) and the first few metal layers of copper interconnect metal in the BEOL (M1 and M2 - the first and second interconnect metal layers in the BEOL of silicon chips). Advanced logic node manufacturers (≤7nm) are exploring new high-k dielectric films such as films of zirconium oxide in combination with cobalt, polysilicon, and silicon dioxide (tetraethyl orthosilicate oxide). To enable complex integration schemes involving the above films, it is desirable to demonstrate that CMP slurries can polish the films with tunable removal rates and selectivity.

[0006] Therefore, there is a need for CMP polishing methods and compositions for selectively polishing cobalt, zirconium oxide, and polysilicon in preference to silicon dioxide. Summary of the invention

[0007] The present invention provides a method for chemical mechanical polishing, which comprises: providing a substrate containing cobalt, zirconium oxide, polysilicon and silicon dioxide; providing a chemical mechanical polishing composition, which comprises the following items as initial components: water, colloidal silica abrasive, cobalt chelating agent, corrosion inhibitor, benzyl trialkyl quaternary ammonium compound having the following formula:

[0008]

[0009] Where R 1 , R 2 and R 3Each independently selected from (C1-C4) alkyl, and, optionally, a biocide; optionally, a pH adjuster, and the pH is greater than 7, and the chemical mechanical polishing composition does not contain an oxidizing agent; providing a chemical mechanical polishing pad having a polishing surface; generating dynamic contact at the interface between the chemical mechanical polishing pad and the substrate; and dispensing the chemical mechanical polishing composition onto the polishing surface of the chemical mechanical polishing pad at or near the interface between the chemical mechanical polishing pad and the substrate; wherein some of the cobalt, zirconium oxide, polycrystalline silicon and silicon dioxide are polished off the substrate.

[0010] The present invention further provides a method for chemical mechanical polishing, which comprises: providing a substrate comprising cobalt, zirconium oxide, polysilicon and silicon dioxide; providing a chemical mechanical polishing composition, which comprises the following items as initial components: water, colloidal silica abrasive having a negative zeta potential, a cobalt chelating agent, a corrosion inhibitor; a benzyl trialkyl quaternary ammonium compound having the following formula:

[0011]

[0012] Where R 1 , R 2 and R 3 Each independently selected from (C1-C4) alkyl, and, optionally, a biocide; optionally, a pH adjuster, and the pH is greater than 7, and the chemical mechanical polishing composition does not contain an oxidizing agent; providing a chemical mechanical polishing pad having a polishing surface; generating dynamic contact at the interface between the chemical mechanical polishing pad and the substrate; and dispensing the chemical mechanical polishing composition onto the polishing surface of the chemical mechanical polishing pad at or near the interface between the chemical mechanical polishing pad and the substrate; wherein some of the cobalt, zirconium oxide, polycrystalline silicon and silicon dioxide are polished off the substrate.

[0013] The present invention further provides a method for chemical mechanical polishing, which comprises: providing a substrate comprising cobalt, zirconium oxide, polysilicon and silicon dioxide; providing a chemical mechanical polishing composition, which comprises the following items as initial components: water, a colloidal silica abrasive having a negative zeta potential, a cobalt chelating agent selected from one or more amino acids, a corrosion inhibitor selected from one or more heterocyclic nitrogen compounds and non-aromatic polycarboxylic acids, and a benzyl trialkyl quaternary ammonium compound having the following formula:

[0014]

[0015] Where R 1 , R 2 and R 3Each independently selected from (C1-C4) alkyl, and, a biocide; optionally, a pH adjuster, and the pH is greater than 7, and the chemical mechanical polishing composition does not contain an oxidizing agent; providing a chemical mechanical polishing pad having a polishing surface; generating dynamic contact at the interface between the chemical mechanical polishing pad and the substrate; and dispensing the chemical mechanical polishing composition onto the polishing surface of the chemical mechanical polishing pad at or near the interface between the chemical mechanical polishing pad and the substrate; wherein some of the cobalt, zirconium oxide, polycrystalline silicon and silicon dioxide are polished off from the substrate.

[0016] The aforementioned method of the present invention includes a chemical mechanical polishing composition comprising the following items as initial components: water, colloidal silica abrasive, cobalt chelating agent, corrosion inhibitor, benzyl trialkyl quaternary ammonium compound having the following formula:

[0017]

[0018] Where R 1 , R 2 and R 3 Each is independently selected from (C1-C4) alkyl, and, optionally, a biocide; optionally, a pH adjuster, and the pH is greater than 7, and the chemical mechanical polishing composition does not contain an oxidizing agent, wherein polishing cobalt, zirconium oxide and polysilicon is selectively preferred to silicon dioxide. DETAILED DESCRIPTION

[0019] As used throughout this specification, unless the context indicates otherwise, the following abbreviations have the following meanings: °C = degrees Celsius; g = gram; L = liter; mL = milliliter; μ = μm = micrometer; kPa = kilopascal; = Angstrom; mV = millivolt; DI = deionized; mm = millimeter; cm = centimeter; min = minute; sec = second; rpm = revolutions per minute; lbs = pounds; kg = kilogram; Co = cobalt; ZrOx, where x = 1 to 2 = zirconium oxide; BTMAH = benzyltrimethylammonium hydroxide; TBAH = tetrabutylammonium hydroxide; H2O2 = hydrogen peroxide; KOH = potassium hydroxide; wt% = weight percent; PVD = physical vapor deposition; RR = removal rate; PS = polishing slurry; and CS = control slurry.

[0020] The term "chemical mechanical polishing" or "CMP" refers to a process of polishing a substrate solely by chemical and mechanical forces, and is distinguished from electrochemical-mechanical polishing (ECMP) in which an electrical bias is applied to the substrate. The term "poly-silicon" means polycrystalline silicon, also known as polycrystalline Si (poly-Si), which is a high-purity, polycrystalline form of silicon that consists of small crystals or crystallites <1 mm and is different from single-crystal silicon and amorphous silicon. The term "amino acid" means an organic compound containing only amine (-NH2) and carboxyl (-COOH) functional groups and side chains (R groups) unique to each amino acid. The term "TEOS" means silicon dioxide formed by the decomposition of tetraethyl orthosilicate (Si(OC2H5)4). The term "high-k" dielectric means that a material such as zirconium oxide has a dielectric constant greater than that of silicon dioxide. The term "a / an" refers to both the singular and the plural. Unless otherwise indicated, all percentages are by weight. All numerical ranges are inclusive and combinable in any order, except where it is logical to constrain the numerical ranges to add up to 100%.

[0021] The method of polishing a substrate of the present invention, wherein the substrate comprises cobalt, zirconium oxide, polycrystalline silicon and silicon dioxide, comprises a chemical mechanical polishing composition containing (preferably consisting of) the following as initial components: water, colloidal silica abrasive, cobalt chelating agent, corrosion inhibitor, benzyl trialkyl quaternary ammonium compound having the following formula:

[0022]

[0023] Where R 1 , R 2 and R 3 Each is independently selected from (C1-C4) alkyl, wherein the anion is hydroxide, halide, nitrate, carbonate, sulfate, phosphate or acetate, and, optionally, a biocide; optionally a defoaming agent; optionally, a pH adjuster, and the pH is greater than 7, and the chemical mechanical polishing composition does not contain an oxidizing agent to provide removal of at least some of the cobalt, zirconium oxide, polysilicon and silicon dioxide from the surface of the substrate to provide a cobalt, zirconium oxide and polysilicon removal rate selectivity relative to silicon dioxide.

[0024] Preferably, in the method of polishing a substrate of the present invention, water contained as an initial component in the provided chemical mechanical polishing composition is at least one of deionized water and distilled water to limit incidental impurities.

[0025] The chemical mechanical polishing composition used in the chemical mechanical polishing method of the present invention preferably contains, as an initial component, 0.01 to 5 wt % of a benzyl trialkyl quaternary ammonium compound having the formula (I):

[0026]

[0027] Where R 1 , R 2 and R 3 Each is independently selected from (C1-C4) alkyl, preferably (C1-C2) alkyl, most preferably methyl; and wherein the anion is a counter anion that neutralizes the positive (+) charge of the benzyltrialkylammonium cation, wherein the anion is hydroxide, halide, nitrate, carbonate, sulfate, phosphate or acetate, preferably, the anion is hydroxide or halide, such as chloride, bromide, fluoride or iodide. Preferably, the halide is chloride or bromide. Most preferably, the halide is chloride. The chemical mechanical polishing composition of the present invention also contains 0.1 to 3 wt%, more preferably 0.1 to 2 wt%, most preferably 0.2 to 1 wt% of a benzyltrialkylquaternary ammonium compound having formula (I) as an initial component. Preferably, the benzyltrialkylammonium compound having formula (I) is benzyltrimethylammonium hydroxide or benzyltrimethylammonium chloride. Most preferably, the benzyltrialkylammonium compound having formula (I) is benzyltrimethylammonium hydroxide.

[0028] In the method of polishing a substrate of the present invention, a chemical mechanical polishing composition is provided that does not contain an oxidizing agent. Oxidizing agents within the scope of the present invention are compounds used to form soft metal oxides that can be polished faster than harder metal surfaces when in the presence of appropriate slurry chemistry and pH. Such oxidizing agents excluded from the chemical mechanical polishing composition of the present invention include, but are not limited to, hydrogen peroxide (H2O2), monopersulfates, iodates, magnesium perphthalate, peracetic acid and other peracids, persulfates, bromates, perbromates, persulfates, peracetic acid, periodates, nitrates, iron salts, cerium salts, Mn(III) salts, Mn(IV) salts and Mn(VI) salts, silver salts, copper salts, chromium salts, cobalt salts, halogens, hypochlorites, and mixtures thereof. Preferably, the chemical mechanical polishing composition of the present invention does not contain hydrogen peroxide, perchlorates, perbromates; periodates, persulfates, peracetic acid, or mixtures thereof. Most preferably, the chemical mechanical polishing composition does not contain the oxidizing agent hydrogen peroxide.

[0029] In the method for chemical mechanical polishing of a substrate of the present invention, the chemical mechanical polishing composition comprises colloidal silica abrasive particles. Preferably, in the method for polishing a substrate of the present invention, the chemical mechanical polishing composition provided contains colloidal silica abrasive having a particle diameter of 200 nm or less and a negative zeta potential. More preferably, in the method for polishing a substrate of the present invention, the chemical mechanical polishing composition provided contains colloidal silica abrasive having an average particle diameter of 200 nm or less and a permanent negative zeta potential, wherein the chemical mechanical polishing composition has a pH greater than 7, preferably, 8 to 13; more preferably, 8.5 to 11; still more preferably, 9 to 11; and most preferably 9 to 10.5. Still more preferably, in the method for polishing a substrate of the present invention, a chemical mechanical polishing composition is provided containing a colloidal silica abrasive having an average particle diameter of 200 nm or less and a permanent negative zeta potential, wherein the chemical mechanical polishing composition has a pH greater than 7, preferably 8 to 13; more preferably, 8.5 to 11; still more preferably, 9 to 11; and most preferably 9 to 10.5, wherein the zeta potential is -0.1 mV to -40 mV, preferably -10 mV to -38 mV, more preferably -20 mV to -36 mV.

[0030] Preferably, in the method for polishing a substrate of the present invention, the provided chemical mechanical polishing composition contains as an initial component a colloidal silica abrasive having an average particle diameter of 200 nm or less, preferably 5 nm to 200 nm, more preferably 5 nm to less than 200 nm, even more preferably 10 nm to 175 nm, still more preferably 10 nm to 150 nm, most preferably 20 nm to 100 nm as measured by a dynamic light scattering technique or a disc centrifuge method. Suitable particle size measuring instruments are available, for example, from Malvern Instruments (Malvern, UK) or CPS Instruments (Prairville, Los Angeles, USA).

[0031] An example of commercially available colloidal silica particles is Fuso PL-3 or SH-3 (average particle diameter of 55 nm) available from Fuso Chemical Co., LTD.

[0032] Preferably, in the method for polishing a substrate of the present invention, the provided chemical mechanical polishing composition contains 0.01 wt% to 10 wt%, preferably 0.05 wt% to 5 wt%, more preferably 0.1 wt% to 5 wt%, even more preferably 0.2 wt% to 5 wt%, and most preferably 1 wt% to 5 wt% of colloidal silica abrasive having a particle diameter of less than or equal to 200 nm, preferably 5 nm to 200 nm, more preferably 5 nm to less than 175 nm, even more preferably 10 nm to 150 nm, still more preferably 20 nm to 150 nm, most preferably 20 nm to 100 nm as measured by dynamic light scattering techniques. Preferably, the colloidal silica abrasive has a negative zeta potential.

[0033] In the method for polishing a substrate of the present invention, the chemical mechanical polishing composition provided contains a corrosion inhibitor as an initial component, wherein the corrosion inhibitor is selected from the group consisting of heterocyclic nitrogen compounds, non-aromatic polycarboxylic acids, and mixtures thereof, wherein the heterocyclic nitrogen compound is selected from the group consisting of adenine, 1,2,4-triazole, imidazole, benzotriazole, polyimidazole, and mixtures thereof; and wherein the non-aromatic polycarboxylic acid includes but is not limited to oxalic acid, succinic acid, adipic acid, maleic acid, malic acid, glutaric acid, citric acid, salts thereof, or mixtures thereof. Preferably, the salt of the aforementioned non-aromatic polycarboxylic acid is selected from one or more of sodium salt, potassium salt, and ammonium salt. When in the method for polishing a substrate of the present invention, the chemical mechanical polishing composition contains a heterocyclic nitrogen compound, preferably, as an initial component, the heterocyclic nitrogen compound is adenine. When in the method for polishing a substrate of the present invention, the chemical mechanical polishing composition contains a non-aromatic polycarboxylic acid, the chemical mechanical polishing composition provided contains as an initial component, preferably, the non-aromatic polycarboxylic acid is selected from the group consisting of malic acid, oxalic acid, adipic acid, citric acid, salts thereof, and mixtures thereof. More preferably, when the provided chemical mechanical polishing composition contains a non-aromatic polycarboxylic acid as an initial component, the non-aromatic polycarboxylic acid is selected from the group consisting of malic acid, citric acid, adipic acid, salts thereof, and mixtures thereof. Most preferably, in the method for polishing a substrate of the present invention, when the provided chemical mechanical polishing composition contains a non-aromatic polycarboxylic acid as an initial component, the non-aromatic polycarboxylic acid is a non-aromatic dicarboxylic acid adipic acid or a salt thereof, wherein, preferably, the salt is selected from the group consisting of sodium adipate, potassium adipate, and ammonium adipate.

[0034] The corrosion inhibitor is contained in the chemical mechanical polishing composition, which contains as an initial component 0.001wt% to 1wt%, more preferably 0.001wt% to 0.05wt%, even more preferably 0.005wt% to 0.01wt% of the corrosion inhibitor, the corrosion inhibitor is selected from the group consisting of heterocyclic nitrogen compounds, non-aromatic polycarboxylic acids and mixtures thereof, wherein the heterocyclic nitrogen compound is selected from the group consisting of adenine, 1,2,4-triazole, imidazole, polyimidazole and mixtures thereof; and wherein the non-aromatic polycarboxylic acid is selected from the group consisting of oxalic acid, succinic acid, adipic acid, maleic acid, malic acid, glutaric acid, citric acid, salts thereof and mixtures thereof. Preferably, in the method for polishing a substrate of the present invention, the provided chemical mechanical polishing composition contains as an initial component 0.001 to 1wt%, more preferably 0.001 to 0.05wt%, most preferably 0.005wt% to 0.01wt% of the heterocyclic nitrogen compound adenine.

[0035] In the method for polishing a substrate of the present invention, the chemical mechanical polishing composition provided contains a cobalt chelator as an initial component. Preferably, the cobalt chelator is an amino acid. Such amino acids include, but are not limited to, alanine, arginine, aspartic acid, cysteine, glutamine, glutamic acid, glycine, histidine, isoleucine, leucine, lysine methionine, phenylalanine, proline, serine, threonine, tryptophan, tyrosine, valine, and mixtures thereof. Preferably, the amino acid is selected from the group consisting of alanine, arginine, glutamine, glycine, leucine, lysine, serine, and mixtures thereof, more preferably, the amino acid is selected from the group consisting of alanine, glutamine, glycine, lysine, serine, and mixtures thereof, even more preferably, the amino acid is selected from the group consisting of alanine, glycine, serine, and mixtures thereof, most preferably, the amino acid is glycine.

[0036] The chelating agent is included in the chemical mechanical polishing composition as an initial component at 0.001 wt % to 1 wt %, more preferably 0.05 wt % to 0.5 wt %, even more preferably 0.05 wt % to 0.1 wt %, most preferably 0.025 wt % to 0.1 wt %.

[0037] In the method for polishing a substrate of the present invention, the provided chemical mechanical polishing composition has a pH greater than 7. Preferably, in the method for polishing a substrate of the present invention, the provided chemical mechanical polishing composition has a pH of 8 to 13. More preferably, in the method for polishing a substrate of the present invention, the provided chemical mechanical polishing composition has a pH of 8.5 to 11, even more preferably 9 to 11; and most preferably, in the method for polishing a substrate of the present invention, the provided chemical mechanical polishing composition has a pH of 9 to 10.5.

[0038] Preferably, in the method for polishing a substrate of the present invention, the provided chemical mechanical polishing composition optionally contains a pH adjuster. Preferably, the pH adjuster is selected from the group consisting of an inorganic pH adjuster and an organic pH adjuster. Preferably, the pH adjuster is selected from the group consisting of an inorganic acid and an inorganic base. More preferably, the pH adjuster is selected from the group consisting of nitric acid and potassium hydroxide. Most preferably, the pH adjuster is potassium hydroxide.

[0039] Optionally, in the method of the present invention, the chemical mechanical polishing composition contains a biocide, such as KORDEK TM MLX (9.5%-9.9% methyl-4-isothiazolin-3-one, 89.1%-89.5% water and ≤1.0% of related reaction products) or KATHON containing the active ingredients 2-methyl-4-isothiazolin-3-one and 5-chloro-2-methyl-4-isothiazolin-3-one TM CG / ICP II, each manufactured by DuPont de Nemours Company (KATHON and KORDEK are trademarks of DuPont).

[0040] In the method for polishing a substrate of the present invention, optionally, the provided chemical mechanical polishing composition may contain 0.001 wt % to 0.1 wt %, preferably 0.001 wt % to 0.05 wt %, more preferably 0.01 wt % to 0.05 wt %, still more preferably 0.01 wt % to 0.025 wt % of a biocide as an initial component.

[0041] Optionally, in the method of the present invention, the chemical mechanical polishing composition may further comprise a defoaming agent, such as a nonionic surfactant, including esters, ethylene oxide, alcohols, ethoxylates, silicon compounds, fluorine compounds, ethers, glycosides and derivatives thereof. Anionic ether sulfates, such as sodium lauryl ether sulfate (SLES) and potassium and ammonium salts. The surfactant may also be an amphoteric surfactant.

[0042] In the method for polishing a substrate of the present invention, optionally, the provided chemical mechanical polishing composition may contain, as an initial component, 0.001 wt % to 0.1 wt %, preferably 0.001 wt % to 0.05 wt %, more preferably 0.01 wt % to 0.05 wt %, still more preferably 0.01 wt % to 0.025 wt % of a defoaming agent.

[0043] Preferably, in the method for polishing a substrate of the present invention, the chemical mechanical polishing pad provided may be any suitable polishing pad known in the art. A person of ordinary skill in the art knows to select an appropriate chemical mechanical polishing pad for use in the method of the present invention. More preferably, in the method for polishing a substrate of the present invention, the chemical mechanical polishing pad provided is selected from a woven polishing pad and a non-woven polishing pad. Still more preferably, in the method for polishing a substrate of the present invention, the chemical mechanical polishing pad provided comprises a polyurethane polishing layer. Most preferably, in the method for polishing a substrate of the present invention, the chemical mechanical polishing pad provided comprises a polyurethane polishing layer containing polymer hollow core particles and a polyurethane impregnated non-woven sub-pad. Preferably, the chemical mechanical polishing pad provided has at least one groove on the polishing surface.

[0044] Preferably, in the method of polishing a substrate of the present invention, the provided chemical mechanical polishing composition is dispensed onto the polishing surface of the provided chemical mechanical polishing pad at or near the interface between the chemical mechanical polishing pad and the substrate.

[0045] Preferably, in the method of polishing a substrate of the present invention, a down force of 0.69 to 20.7 kPa perpendicular to the surface of the substrate to be polished is used to generate dynamic contact at the interface between the provided chemical mechanical polishing pad and the substrate.

[0046] Preferably, in the method for polishing a substrate of the present invention, the chemical mechanical polishing composition provided has More preferably, More preferably, The cobalt removal rate of More preferably, More preferably, ZrOx removal rate; More preferably More preferably and, preferably, the Co:TEOS selectivity is ≥20, more preferably the Co:TEOS selectivity is ≥60:1; further preferably, the Co:TEOS selectivity is ≥70; preferably, the ZrOx:TEOS selectivity is ≥4:1; more preferably, the ZrOx:TEOS selectivity is ≥10:1; further preferably, the ZrOx:TEOS selectivity is ≥13:1; and, preferably, the polycrystalline Si:TEOS selectivity is 30:1, more preferably, the polycrystalline Si:TEOS selectivity is ≥100:1; and, wherein a 26 mm square test wafer is used on a Bruker Tribolab CMP polisher, with a platen speed of 120 rpm, a carriage speed of 117 rpm, a chemical mechanical polishing composition flow rate of 100 mL / min, and a nominal downforce of 20.7 kPa; and, wherein the chemical mechanical polishing pad comprises a polyurethane polishing layer containing polymer hollow core particles and a polyurethane impregnated nonwoven subpad.

[0047] The following examples are intended to illustrate the present invention but are not intended to limit its scope.

[0048] Example 1

[0049] Slurry preparation

[0050] All slurries used for polishing studies in Table 1 were prepared as mentioned in the following procedure. Glycine and adenine were added to deionized water and mixed using an overhead stirrer (300-450 RPM) until completely dissolved so that the final glycine concentration was 0.1 wt% and the final adenine concentration was 0.01 wt%, followed by pH adjustment to a pH of 10.3 with dilute KOH solution (5% or 45%). Colloidal silica particles were obtained from Fuso Chemical Co., Ltd.: Fuso SH-3 (55 nm average diameter cocoon-shaped colloidal silica particles, forming interconnected spheres with an average length of 70 nm, 34 wt% solids as received). KORDEK TM MLX biocide was added to the slurry followed by TBAH or BTMAH in the amounts shown in Table 1. Cleanroom grade H2O2 (30% solution) was added with stirring to achieve a 0.3 wt% H2O2 concentration in the final slurry. In polishing experiments, the slurries were used on the same day or the next day after the H2O2 addition.

[0051] Table 1

[0052] Slurry preparation

[0053]

[0054]

[0055]

[0056] Example 2

[0057] Polishing experiment

[0058] The following cobalt, zirconium oxide, polysilicon, and silicon dioxide polishing experiments were conducted using the slurries disclosed in Table 1 in Example 1 above.

[0059] Table 2

[0060] CMP polishing and cleaning conditions

[0061]

[0062] Cobalt film thickness using OMNIMAP TM The film thicknesses of zirconium oxide, poly-Si and TEOS were measured with an RS200 and the film thicknesses of zirconium oxide, poly-Si and TEOS were measured with an Asset F5x measurement tool, both from KLA Corporation. The polishing results are in Table 3 below.

[0063] Table 3

[0064] Removal rate and selectivity

[0065]

[0066] Example 3

[0067] Static Etch Rate (Corrosion) Analysis

[0068] Blanket Co wafers (200 mm, approx. Thick, PVD, Co deposited onto silicon substrate) was used as received. Gamry PTC1 TM The paint test cell is used for analysis, with the entire 200mm Co wafer clamped in a glass tube with an O-ring seal and a custom TEFLON TM Between the substrates. 3M-470 (with 3.0 cm 2The open area of ​​the plater tape) is used between the wafer and the O-ring to avoid any cracks or stress-type local corrosion. For high temperature analysis, 30mL of static etching slurry is kept in an oven at 55°C to simulate the higher local temperature at the pad bump / wafer contact during polishing and preheated for 60min, and then the slurry is immediately added to the static etching unit and kept in contact with the wafer for 3min. After the desired holding time, the static etching solution is collected and analyzed by inductively coupled plasma emission spectrometer (ICP-OES) analysis after centrifugation and separation of colloidal silica abrasive (when present in the formulation) for Co ions. Colloidal silica abrasive is excluded from some formulations in the static etching experiment to facilitate ICP-OES analysis. At least two data points are collected for all test slurries to check reproducibility.

[0069] The cobalt static etch rate (SER) was calculated from the cobalt concentration analyzed by ICP using the following formula:

[0070] Cobalt SER

[0071] C = Co concentration from ICP analysis (g / l)

[0072] V = volume of the test solution used added to the static etching apparatus (l)

[0073] A = Area of ​​cobalt metal exposed to the test solution (cm 2 )

[0074] D = density of cobalt (8.9 g / cm 3 )

[0075] T = exposure time (min)

[0076] 10^ 8 =cm to Unit conversion

[0077] Table 4

[0078] Static etching rate at 55℃

[0079] Slurry cobalt CS 1 <1.5 CS 2 <1.5 CS 3 <1.5 CS 4 <1.5 CS 5 <1.5 CS 6 2.1 CS 7 1.7 CS 8 1.8 CS 9 2.0 PS 1 <1.5 PS 2 <1.5 PS 3 <1.5 PS 4 <1.5

Claims

1. A method for chemical mechanical polishing, the method comprising: providing a substrate comprising cobalt, zirconium oxide, polysilicon and silicon dioxide; A chemical mechanical polishing composition is provided, which comprises the following items as initial components: water, Colloidal silica abrasive, 0.001wt% to 1wt% of a cobalt chelating agent, 0.001 wt% to 1 wt% of a corrosion inhibitor, and 0.01 wt% to 5 wt% of a benzyl trialkyl quaternary ammonium compound having the formula: Where R 1 , R 2 and R 3 are each independently selected from (C1-C4)alkyl, wherein the pH of the chemical mechanical polishing composition is greater than 7, and the chemical mechanical polishing composition does not contain an oxidizing agent; Providing a chemical mechanical polishing pad having a polishing surface; creating dynamic contact at an interface between the chemical mechanical polishing pad and the substrate; as well as The chemical mechanical polishing composition is dispensed onto a polishing surface of the chemical mechanical polishing pad at or near an interface between the chemical mechanical polishing pad and the substrate to remove at least some of the cobalt.

2. The method of claim 1, wherein: The benzyl trialkyl quaternary ammonium compound is in an amount of 0.1-3 wt%.

3. The method of claim 1, wherein: The benzyltrialkyl quaternary ammonium compound is selected from the group consisting of benzyltrimethylammonium hydroxide, benzyltrimethylammonium chloride and mixtures thereof.

4. The method of claim 1, wherein: The anion is selected from the group consisting of hydroxide, halide, nitrate, carbonate, sulfate, phosphate and acetate.

5. The method of claim 1, wherein: The colloidal silica abrasive has a permanent negative zeta potential.

6. The method of claim 1, wherein: The corrosion inhibitor is a heterocyclic nitrogen compound, an aromatic polycarboxylic acid or a mixture thereof.

7. The method of claim 1, wherein: The chelating agent is an amino acid.

8. The method of claim 7, wherein: The amino acid is selected from the group consisting of alanine, arginine, aspartic acid, cysteine, glutamine, glutamic acid, glycine, histidine, isoleucine, leucine, lysine methionine, phenylalanine, proline, serine, threonine, tryptophan, tyrosine, valine and mixtures thereof.

9. The method of claim 1, wherein: The pH is 8-13.

10. The method of claim 1, wherein: The chemical mechanical polishing composition also includes a biocide.

11. The method of claim 1, wherein: The chemical mechanical polishing composition further comprises a pH adjuster.

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