Polishing composition and method of polishing substrate having improved defect inhibition
Patent Information
- Application Number
- JP2022072274
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- Priority Date
- 2021-04-27
- Filing Date
- 2022-04-26
- Publication Date
- 2025-04-21
- Estimated Expiration
- Not applicable · inactive patent
AI Technical Summary
Existing chemical mechanical polishing (CMP) compositions fail to provide adequate planarization efficiency, uniformity, and dielectric removal rates while minimizing defects such as scratches, which are becoming yield-limiting as semiconductor device sizes shrink.
A chemical mechanical polishing composition comprising a quaternary phosphonium compound with an aromatic group, abrasive grains, and a pH greater than 7, which includes colloidal silica and a biocide, is used to improve defect reduction and silicon oxide removal rates.
The composition achieves improved defect reduction, enhanced silicon oxide removal rates, and stability, reducing scratches by over 50% compared to conventional methods.
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Abstract
Description
[Technical Field]
[0001] Field of Invention The present invention relates to an alkaline polishing composition and a method for polishing a substrate having improved defect reduction with a good insulator removal rate. More specifically, the present invention relates to an alkaline polishing composition and a method for polishing a substrate having improved defect reduction with a good insulator removal rate, wherein the polishing composition comprises a quaternary phosphonium compound having an aromatic group to improve defect reduction on a substrate containing a silicon oxide insulator, and at least a portion of the silicon oxide is removed from the substrate. [Background technology]
[0002] Background of the Invention In the manufacture of integrated circuits and other electronic devices, multiple layers of conductive materials, semiconductor materials, and insulating materials are deposited on or removed from the surface of a semiconductor wafer. Thin layers of conductive materials, semiconductor materials, and insulating materials can be deposited by multiple deposition techniques. Common deposition techniques in modern processing include physical vapor deposition (PVD), also known as sputtering, chemical vapor deposition (CVD), plasma-accelerated chemical vapor deposition (PECVD), and electrochemical plating (ECP).
[0003] As layers of material are sequentially deposited and removed, the top surface of the wafer becomes non-planar. Subsequent semiconductor processing (e.g., metallization) requires the wafer to have a flat surface, so planarization is necessary. Planarization is useful for removing undesirable surface topography and surface defects, such as rough surfaces, aggregated material, crystal lattice damage, scratches, and contaminated layers or materials.
[0004] Chemical mechanical planarization or chemical mechanical polishing (CMP) is a common technique used to planarize substrates, such as semiconductor wafers. In conventional CMP, the wafer is mounted on a carrier assembly and positioned in contact with a polishing pad within the CMP apparatus. The carrier assembly applies controllable pressure to the wafer, pressing it against the polishing pad. This pad is moved relative to the wafer by an external driving force (e.g., rotated). Simultaneously, a polishing composition ("slurry") or other polishing solution is provided between the wafer and the polishing pad. In this way, the wafer surface is polished and flattened by the chemical and mechanical action of the pad surface and the slurry.
[0005] Certain advanced device designs require polishing compositions that provide improved silicon dioxide removal efficiency at lower point-of-use (POU) abrasive weight percentages, as well as reduced scratch defects for improved overall polishing processes and product yield percentages. As the size of structures on semiconductor devices continues to shrink, performance standards that were once acceptable for planarization and defect reduction when polishing insulating materials are becoming increasingly unacceptable. Scratches that were once considered acceptable are now limiting yields. [Overview of the project] [Problems that the invention aims to solve]
[0006] Therefore, there is a need for polishing compositions and polishing methods that exhibit desirable planarization efficiency, uniformity, and insulator removal rate while minimizing defects, such as scratches. [Means for solving the problem]
[0007] Summary of the Invention The present invention relates to water, abrasive particles, optionally a pH adjuster, optionally a biocide, a pH greater than 7, and formula (I): [ka] [wherein, R is selected from the group consisting of phenyl, benzyl and linear or branched C1 - C4 alkyl, and X is Br - , Cl - , I - , F - and OH - and is an anion selected from the group consisting of] Provided is a chemical mechanical polishing composition comprising a quaternary phosphonium compound having]
[0008] Also, the present invention relates to water, 0.1 - 40% by weight of abrasive grains, optionally a pH adjuster, optionally a biocide, a pH of 7 or more, 0.001 - 1% by weight of formula (I): [Chemical formula] [wherein, R is selected from the group consisting of phenyl, benzyl and linear or branched C1 - C4 alkyl, and X is Br - , Cl - , I - , F - and OH - and is an anion selected from the group consisting of] Also provided is a chemical mechanical polishing composition comprising a quaternary phosphonium compound having]
[0009] Furthermore, the present invention relates to water, 5 - 25% by weight of colloidal silica abrasive grains, a pH adjuster, optionally a biocide, a pH of 8 - 13, 0.01 - 1% by weight of formula (I): [Chemical formula] [wherein, R is selected from the group consisting of phenyl, benzyl and linear or branched C1 - C4 alkyl, and X is Br - , Cl - , I - , F - and OH - and is an anion selected from the group consisting of] Provided is a chemical mechanical polishing composition comprising a quaternary phosphonium compound having .
[0010] The present invention provides a substrate containing silicon oxide, water, abrasive grains, optionally a pH adjuster, optionally a biocide, a pH of more than 7, and formula (I):
Chemical formula
Advantages of the Invention
[0011] The chemical mechanical polishing composition and method of the present invention enable improved defect reduction, enable a good silicon oxide removal rate, and the chemical mechanical polishing composition is stable.
Embodiments for Carrying out the Invention
[0012] Detailed Description of the Invention Throughout this specification, the following abbreviations have the meanings set forth below unless otherwise specified: L = liter, mL = milliliter, kPa = kilopascal, Å = angstrom, nm = nanometer, min = minute, rpm = revolutions per minute, wt% = weight%, RR = removal rate, mmol = millimoles, Br - = Bromide, Cl - = Chloride, I - = Yogid, F - =Fluoride, OH - =Hydroxide, PS =Polishing slurry of the present invention, PC =Comparative polishing slurry.
[0013] The term "chemical-mechanical polishing" or "CMP" refers to a process in which a substrate is polished by chemical and mechanical forces alone, and is distinguished from electrochemical-mechanical polishing (ECMP), in which an electrical bias is applied to the substrate. The term "TEOS" means silicon dioxide formed by the decomposition of tetraethyl orthosilica (Si(OC2H5)4). The terms "composition" and "slurry" are used interchangeably throughout this specification. The term "halide" means chloride, bromide, fluoride, and iodide. The terms "a" and "an" refer to both singular and plural forms. All percentages are by weight unless otherwise specified. All numerical ranges include thresholds and can be combined in any order, unless it is logical to restrict such numerical ranges to sum to 100%.
[0014] The chemical-mechanical polishing composition of the present invention is useful for polishing substrates containing silicon dioxide. The chemical-mechanical polishing composition comprises water, abrasive particles, optionally a pH adjuster, optionally a biocide, a pH greater than 7, and formula (I): [ka] [In the formula, R is selected from the group consisting of phenyl, benzyl, and linear or branched C1-C4 alkyl groups, and X is Br - Cl - , I- F - and OH - An anion selected from the group consisting of [ It comprises a quaternary phosphonium compound that has the properties of reducing defects and improving the rate of silicon dioxide removal from the substrate.
[0015] As used herein, the term "improved silicon dioxide removal rate" refers to the rate of silicon dioxide removal (measured in Å / min) resulting from polishing a substrate with a chemical-mechanical polishing composition containing an aromatic group-containing quaternary phosphonium compound, and means that at least the following formula is satisfied. A>A0
[0016] In the formula, A is the silicon dioxide removal rate (Å / min) for a chemical-mechanical polishing composition containing the claimed quaternary phosphonium compound used in the method of the present invention for polishing a substrate, measured under the polishing conditions described in the example, and A0 is the silicon dioxide removal rate (Å / min) obtained under the same conditions in which only silica abrasive grains are present.
[0017] As used herein, the term "improved polishing defect performance" refers to the defect performance obtained by including a compound having formula (I) in the chemical-mechanical polishing composition used in the chemical-mechanical polishing method of the present invention, and means that at least the following formula is satisfied. X <X0
[0018] In the formula, X is the defect (i.e., post-CMP / hydrogen fluoride (HF) scratch or defect) of the chemical-mechanical polishing composition containing the substance used in the method of the present invention, measured under the polishing conditions described in the example, and X0 is the defect (i.e., post-CMP / hydrogen fluoride scratch or defect) obtained under the same conditions in which only silica abrasive grains are present.
[0019] Preferably, the chemical-mechanical polishing composition of the present invention contains a quaternary phosphonium compound in an amount of 0.001 to 1% by weight, more preferably 0.01 to 1% by weight, and most preferably 0.1 to 0.5% by weight.
[0020] Exemplary quaternary phosphonium compounds include tetraphenylphosphonium bromide, tetraphenylphosphonium chloride, benzyltriphenylphosphonium bromide, benzyltriphenylphosphonium chloride, ethyltriphenylphosphonium bromide, ethyltriphenylphosphonium chloride, methyltriphenylphosphonium bromide, and methyltriphenylphosphonium chloride. A mixture of such quaternary phosphonium compounds can be included in the chemical-mechanical polishing composition of the present invention.
[0021] The water contained in the chemical-mechanical polishing composition used in the chemical-mechanical polishing method of the present invention is preferably at least one of deionized water and distilled water in order to limit accidental impurities.
[0022] The chemical-mechanical polishing composition used in the chemical-mechanical polishing method of the present invention contains 0.1 to 40% by weight of abrasive grains, preferably 5 to 30% by weight, and more preferably 10 to 20% by weight. The abrasive grains that are preferably used have an average particle size of <200 nm, more preferably 75 to 150 nm, and most preferably 100 to 150 nm.
[0023] Abrasive particles for use in the chemical-mechanical polishing composition used in the chemical-mechanical polishing method of the present invention include, for example, inorganic oxides, inorganic hydroxide oxides, metal borides, metal carbides, metal nitrides, polymer particles, and mixtures containing at least one of these. Suitable inorganic oxides include, for example, silica (SiO2), alumina (Al2O3), zirconia (ZrO2), ceria (CeO2), manganese oxide (MnO2), titanium oxide (TiO2), or combinations thereof. Modified forms of these inorganic oxides, such as organic polymer-coated inorganic oxide particles and inorganic coated particles, can also be used as desired. Suitable metal carbides, borides, and nitrides include, for example, silicon carbide, silicon nitride, silicon carbonitride (SiCN), boron carbide, tungsten carbide, zirconium carbide, aluminum boride, tantalum carbide, titanium carbide, or combinations thereof.
[0024] The preferred abrasive grain for use in the chemical-mechanical polishing composition used in the chemical-mechanical polishing method of the present invention is colloidal silica. Preferably, the colloidal silica used contains at least one of precipitated silica and aggregated silica. Preferably, the colloidal silica used has an average particle size of <200 nm, more preferably 75 to 150 nm, most preferably 100 to 150 nm, and accounts for 0.1 to 40% by weight, preferably 5 to 30% by weight, more preferably 10 to 20% by weight of the chemical-mechanical polishing composition. Examples of commercially available colloidal silica include Klebosol® II 1630 colloidal silica with an average particle size of 139 nm, Klebosol® II 1630 colloidal silica with an average particle size of 145 nm, and Klebosol® II 1730 colloidal silica with a particle size of 130 nm. These are all manufactured by Merck KgAA, Darmstadt, Germany, and are all available from DuPont.
[0025] Optionally, the chemical-mechanical polishing composition may contain a biocide, for example, KORDEK™ MLX (9.5-9.9% methyl-4-isothiazolin-3-one, 89.1-89.5% water, and ≤1.0% related reaction product) or KATHON™ ICP III (KATHON and KORDEK are trademarks of International Flavors & Fragrances, Inc.), which contains the active ingredients 2-methyl-4-isothiazolin-3-one and 5-chloro-2-methyl-4-isothiazolin-3-one, respectively, manufactured by International Flavors & Fragrances, Inc.
[0026] If a biocide is included in the chemical-mechanical polishing composition of the present invention, the biocide is included in an amount of 0.001% to 0.1% by weight, preferably 0.001% to 0.05% by weight, more preferably 0.001% to 0.01% by weight, and even more preferably 0.001% to 0.005% by weight.
[0027] The chemical-mechanical polishing composition used in the chemical-mechanical polishing method of the present invention has a pH of 7, preferably 7 to 12, and more preferably 10 to 11.
[0028] The chemical-mechanical polishing composition used may optionally contain one or more pH adjusters to maintain the pH within a preferred range. Preferably, the pH adjuster is selected from one or more of sodium hydroxide, potassium hydroxide, and ammonium salts, such as halides or nitrates.
[0029] The substrate polished in the chemical-mechanical polishing method of the present invention contains silicon dioxide. The silicon dioxide in the substrate includes, but is not limited to, boric acid silicate glass (BPSG), plasma-reinforced tetraethyl orthosilica (PETEOS), thermal oxides, undoped silicate glass, and high-density plasma (HDP) oxides.
[0030] The chemical-mechanical polishing pad used in the chemical-mechanical polishing method of the present invention can be any suitable polishing pad known in the art. The chemical-mechanical polishing pad can be optionally selected from woven and non-woven polishing pads. The chemical-mechanical polishing pad can be made of any suitable polymer with various densities, hardnesses, thicknesses, compressibility, and moduli. The chemical-mechanical polishing pad can be grooved and perforated as desired.
[0031] The quaternary phosphonium compound having formula (I) contained in the chemical-mechanical polishing composition used in the chemical-mechanical polishing method of the present invention provides improved polishing defect resistance. Preferably, the inclusion of the quaternary phosphonium compound having formula (I) in the chemical-mechanical polishing composition results in a >50% reduction in polishing defect resistance (i.e., post-CMP / hydrogen fluoride scratch) when measured under the polishing conditions described in the example. That is, preferably, at least the following formula is satisfied. (X0-X) / X0 * 100>50
[0032] In the formula, X is the polishing defect (i.e., post-CMP / hydrofluoride scratch or defect) of a chemical-mechanical polishing composition containing the quaternary phosphonium compound represented by formula (I) used in the method of the present invention, measured under the polishing conditions described in the example, and X0 is the polishing defect (i.e., post-CMP / hydrofluoride scratch or defect) obtained under the same conditions in the presence of silica abrasive grains alone or silica abrasive grains and the symmetric quaternary phosphonium compound.
[0033] The chemical-mechanical polishing composition used in the chemical-mechanical polishing method of the present invention enables operation at low nominal polishing pad pressures, for example, 3 to 35 kPa. Low nominal polishing pad pressure improves polishing performance by reducing scratches and other undesirable polishing defects, and minimizes damage to fragile materials. [Examples]
[0034] The following examples are intended to illustrate the present invention and not to limit its scope.
[0035] In the examples below, unless otherwise specified, the temperature and pressure conditions are ambient temperature and standard pressure.
[0036] In the example below, the following materials were used.
[0037] Polishing removal rate experiments were conducted on 8-inch blanket wafers. An Applied Materials Mirra® polisher was used in Examples 1 and 2, and an Applied Materials Reflexion® polisher was used in Examples 3 and 4. Examples 1 and 2 used a VisionPad 5000 / K7® polyurethane polishing pad, while Examples 3 and 4 used an IC1010 polyurethane polishing pad (both commercially available from Rohm and Haas Electronic Materials CMP Inc.). The experiments were performed with a downforce of 20.7 kPa (3 psi), a chemical-mechanical polishing slurry flow rate of 150 mL / min for Examples 1 and 2, and 250 mL / min for Examples 3 and 4, a table rotation speed of 93 rpm, and a carrier rotation speed of 87 rpm. Removal rates were determined by measuring the film thickness before and after polishing using a KLA-Tencor FX200 measuring tool. The defect performance reported in the example was determined using a scanning electron microscope after hydrofluoric acid polishing and cleaning ("Pst-HF"). All TEOS wafers after Pst-HF cleaning were inspected using the Surfscan® SP2 defect inspection system available from KLA-Tencor. Defect information, including their coordinates on the wafer, was recorded in KLARF (KLA results file), and then transferred to the eDR-5200 defect review system available from KLA-Tencor. A random sample of 100 defect images was selected and examined by the eDR-5200 system. These 100 images were classified into various defect types, e.g., chatter marks (scratches), particles, and pad polishing debris. Based on the classification results from these 100 images, the total number of scratches on the wafer was determined.
[0038] Example 1 Chemical mechanical polishing composition, TEOS RR and defect reduction Aqueous chemical-mechanical polishing slurries were prepared as shown in Table 1 below. A 2% by weight aqueous KOH solution was added to each slurry to maintain the desired pH.
[0039] [Table 1]
[0040] [Table 2]
[0041] The slurry of the present invention showed a significant TEOS RR compared to the slurry of the comparative example, resulting in reduced defect count and reduced scratches.
[0042] Example 2 Chemical mechanical polishing composition, TEOS RR and defect reduction Aqueous chemical-mechanical polishing slurries were prepared as shown in Table 3 below. A 2% by weight aqueous KOH solution was added to each slurry to maintain the desired pH.
[0043] [Table 3]
[0044] [Table 4]
[0045] The slurry of the present invention containing tetraphenylphosphonium chloride showed improved TEOS RR and reduced defects and scratches compared to two comparative examples.
[0046] Example 3 Chemical mechanical polishing composition, TEOS RR and scratch reduction Aqueous chemical-mechanical polishing slurries were prepared as shown in Table 3 below. A 2% by weight aqueous KOH solution was added to each slurry to maintain the desired pH.
[0047] [Table 5]
[0048] [Table 6]
[0049] In the slurry of the present invention, the TEOS RR was significantly improved and scratching was reduced compared to a comparative example slurry that did not contain a quaternary phosphonium compound.
[0050] Example 4 Stability of chemical mechanical polishing compositions Aqueous chemical-mechanical polishing compositions were prepared to test their stability. The pH of the compositions was maintained at 10.7. Samples were left under static conditions at room temperature and pressure for two weeks, and then visually inspected.
[0051] [Table 7]
[0052] The chemical-mechanical polishing composition of the present invention was stable at a concentration of 0.0021 to 0.0028 mmol of quaternary phosphonium compound.
Claims
1. Water, an abrasive, optionally a pH adjuster, optionally a biocide, a pH greater than 7 and a composition of formula (I): 【Chemistry 6】 [wherein R is phenyl, benzyl, and straight or branched chain C １ ~C ４ alkyl; X is selected from the group consisting of Br － , Cl － , I － , F － and OH － is an anion selected from the group consisting of A quaternary phosphonium compound having the formula: Chemical mechanical polishing compositions.
2. Water, 0.1-40% by weight of abrasive grains, optionally a pH adjuster, optionally a biocide, a pH greater than 7, and 0.001-1% by weight of a composition of formula (I): 【Chemistry 7】 [wherein R is phenyl, benzyl, and straight or branched chain C １ ~C ４ alkyl; X is selected from the group consisting of Br － , Cl － , I － , F － and OH － is an anion selected from the group consisting of 2. The chemical mechanical polishing composition of claim 1, comprising a quaternary phosphonium compound having the formula:
3. Water, 5-25% by weight of an abrasive (wherein the abrasive is a colloidal silica abrasive), a pH adjuster, a biocide, a pH of 8-13, and 0.01-1% by weight of a compound of formula (I): 【Chemistry 8】 [wherein R is phenyl, benzyl, and straight or branched chain C １ ~C ４ alkyl; X is selected from the group consisting of Br － , Cl － , I － , F － and OH － is an anion selected from the group consisting of 2. The chemical mechanical polishing composition of claim 1, comprising a quaternary phosphonium compound having the formula:
4. 4. The chemical mechanical polishing composition of claim 3, wherein the pH adjuster is selected from the group consisting of potassium hydroxide, sodium hydroxide, ammonium salts, and mixtures thereof.
5. 2. The chemical mechanical polishing composition of claim 1, wherein the quaternary phosphonium compound is selected from the group consisting of tetraphenylphosphonium bromide, tetraphenylphosphonium chloride, benzyltriphenylphosphonium bromide, benzyltriphenylphosphonium chloride, ethyltriphenylphosphonium bromide, ethyltriphenylphosphonium chloride, methyltriphenylphosphonium bromide, methyltriphenylphosphonium chloride, and mixtures thereof.
6. Providing a substrate comprising silicon oxide; Water, an abrasive, optionally a pH adjuster, optionally a biocide, a pH greater than 7, a composition of formula (I): 【Chemistry 9】 [wherein R is phenyl, benzyl, and straight or branched chain C １ ~C ４ alkyl; X is selected from the group consisting of Br － , Cl － , I － , F － and OH － is an anion selected from the group consisting of providing a chemical mechanical polishing composition comprising a quaternary phosphonium compound having the formula: Providing a chemical mechanical polishing pad having an abrasive surface; creating dynamic contact at an interface between the polishing surface of the chemical mechanical polishing pad and the substrate with a downforce of 3-35 kPa; and dispensing a chemical mechanical polishing composition onto the chemical mechanical polishing pad at or near an interface between the chemical mechanical polishing pad and the substrate; removing a portion of the silicon oxide from the substrate; A method for chemical mechanical polishing a substrate.
7. 7. The method of chemical mechanical polishing a substrate according to claim 6, wherein the quaternary phosphonium compound is selected from the group consisting of tetraphenylphosphonium bromide, tetraphenylphosphonium chloride, benzyltriphenylphosphonium bromide, benzyltriphenylphosphonium chloride, ethyltriphenylphosphonium bromide, ethyltriphenylphosphonium chloride, methyltriphenylphosphonium bromide, methyltriphenylphosphonium chloride, and mixtures thereof.