Cleaning composition containing corrosion inhibitor

Abstract

This application relates to cleaning compositions containing corrosion inhibitors. A cleaning composition and method for cleaning microelectronic device substrates within a process, such as post-chemical mechanical polishing (CMP) cleaning, to remove residue from the surface thereof, wherein the cleaning composition can be particularly effective for cleaning substrate surfaces comprising exposed metals such as cobalt, copper, or both, as well as dielectric or low-k dielectric materials, and wherein the cleaning composition includes a corrosion inhibitor to inhibit corrosion of the exposed metals.

Description

[0001] This application is a divisional application of the invention patent application filed on July 18, 2019, with application number 201980047825.X and invention title "Cleaning Composition Containing Corrosion Inhibitor". Technical Field

[0002] The following description relates to a liquid composition for cleaning the surface of a microelectronic device substrate, such as for cleaning residues from the surface of a microelectronic device substrate, wherein the liquid composition contains a corrosion inhibitor. Background Technology

[0003] Microelectronic device substrates are used to fabricate integrated circuit devices. Microelectronic device substrates include a base, such as a silicon wafer with a highly flat surface. Regions of electronic functional features are added to the flat surface of the substrate by means of multiple selective placement and removal steps. Features are formed by selectively adding and removing electronic functional materials that exhibit insulating, conductive, or semi-conductive properties. These electronic functional materials are placed as needed using processing materials, including photoresist, chemical etchants, and slurries containing abrasive particles and chemical materials, which facilitate surface treatment.

[0004] A key feature of integrated circuits is an array of conductive "interconnects," also known as "wires" and "vias." As part of an integrated circuit, conductive interconnects are used to conduct current between and among various other electronic features. Each interconnect is in the form of a line or thin film of conductive material, extending within and defined (in shape and size) by an opening formed in an insulating material (i.e., a dielectric material with low-k dielectric properties). The dielectric material acts as an insulator between the closely spaced interconnect structures and between the interconnect structures and other electronic features of the integrated circuit.

[0005] The types of materials used to create interconnects and low-k dielectric structures must be carefully selected for appropriate use as a component of integrated circuits that perform with high efficiency and high reliability. For example, the conductive material of the interconnects should be of a type that, when there is a voltage between the materials, does not excessively migrate (e.g., diffuse) into the adjacent dielectric material over time and during use; such migration from the interconnect material to the adjacent dielectric material is often referred to as "electromigration." Simultaneously, the combined interconnect and dielectric material structure must possess sufficient integrity, including at the interfaces between these materials, to produce a low level of defects and a high level of performance reliability. For example, strong bonding must exist at the interfaces to prevent the low-k dielectric material from separating from the interconnect material during use.

[0006] In the past, interconnects were typically made of aluminum or tungsten, and more recently, copper. Copper offers advantageous high conductivity compared to aluminum and tungsten. Furthermore, copper-based interconnects provide better electromigration resistance compared to aluminum, thereby improving the reliability of integrated circuits over time. However, copper ions can tend to diffuse into silicon dioxide (SiO2) under sufficient electrical bias, and the adhesion of copper to silicon dioxide and other dielectric materials may be poor.

[0007] To prevent these negative interactions between copper and dielectric materials, current integrated circuit structures are designed to include a barrier layer between the copper interconnect structure and the adjacent dielectric material. Examples of barrier layers can be conductive or non-conductive materials, including tantalum (Ta) and tantalum nitride (TaN). x ), tungsten (W), titanium (Ti), titanium nitride (TiN), ruthenium (Ru), cobalt (Co), molybdenum (Mo), rhenium (Rh) and their alloys.

[0008] The process of placing various features of a microelectronic device onto a substrate involves selectively placing insulating materials (e.g., dielectrics, low-k dielectrics, etc.), semiconductor materials, and metallic materials (e.g., wires and vias (i.e., interconnects)) onto the substrate surface. The selective placement and removal of these materials can involve process compositions using, for example, photoresist, etchants, CMP slurries containing abrasives and chemicals, and plasma, particularly in steps such as: photoresist coating, etching (e.g., wet etching, plasma etching), chemical mechanical processing (also known as chemical mechanical polishing, or simply "CMP"), and ashing ("plasma ashing").

[0009] Chemical mechanical processing (CMP) is a method for precisely removing a very small amount (thickness) of material from the surface of a microelectronic device substrate to polish (or “planarize”) the surface, preparing a subsequent material layer to be coated onto the processed surface. CMP involves highly precise mechanical abrasion of the surface coupled with controlled interactions of chemical materials, such as oxidation, reduction, or chelation of materials present on or removed from the surface. Typically, one type of material (e.g., a metallic overlay) on the substrate surface is preferentially removed in a highly selective manner compared to reduced removal of one or more other materials also present on the surface (e.g., dielectric materials).

[0010] CMP (Continuous Metallurgy) methods involve applying a "slurry" to a surface while simultaneously bringing the surface into contact with a moving CMP pad. The "slurry" is a liquid composition containing micro-abrasive particles that provide mechanical abrasion to the surface, and chemical materials that interact with the surface material to promote selective removal of certain materials from the surface and generally inhibit the removal of other surface materials. The slurry is applied to the surface while the CMP pad contacts the surface at the desired pressure and amount of movement to promote both self-surface abrasion and chemical removal of selective materials. The combination of the mechanical action of the pad and the abrasive particles moving against the surface, along with the action of the chemical components, achieves the desired removal, planarization, and polishing of the surface, resulting in a surface with a desired low level of defects and residues. CMP methods should produce highly planar, low-defect, low-residue surfaces on which subsequent layers of microelectronic devices can be applied.

[0011] Following processing steps (such as chemical mechanical processing, etching, ashing, etc.), at least some amount of residue will remain on the substrate surface. This residue may include abrasive particles from CMP slurries or other processing materials; active chemical components that are part of CMP slurries (e.g., oxidants, catalysts, inhibitors) or other processing compositions (e.g., etchants); reaction products or byproducts of the processing materials or their components; chemical etchants; photoresist polymers or other solid processing components, etc. Any such residue must be removed by cleaning the surface before performing subsequent steps in the microelectronic device manufacturing process to avoid defects or other potential sources of reduced device performance or reliability.

[0012] Certain methods and apparatus are commonly used to clean the surfaces of microelectronic substrates, such as after etching, CMP, or another step in the fabrication of multilayer microelectronic devices. These include methods and apparatus involving a combination of a cleaning solution stream on the surface and ultra-high frequency acoustic waves, spraying, or brushing to remove residues and contaminants. Typical cleaning solutions are alkaline solutions, such as those containing suitable hydroxide compounds, and other chemical materials that remove residues from the surface through chemical interaction with them. The cleaning solution should effectively remove a high percentage of residues from the surface, but must also be safe relative to the functional characteristics of the substrate. The cleaning solution must not damage those characteristics. For example, the cleaning solution should not cause corrosion (i.e., oxidation) of the metallic features of the substrate, such as copper or cobalt metallic features that may exist in the form of interconnects or barrier features.

[0013] Various high-pH cleaning compositions used for microelectronic device processing contain ingredients such as alkaline compounds, cleaning compounds, chelating agents, surfactants, oxidants, and corrosion inhibitors. There is a constant search for new, useful, and improved cleaning compositions and specific components, especially for use with new microelectronic device structures, such as those that may now include copper or cobalt as interconnects or barrier structures. Many alkaline compounds are known and suitable for alkaline cleaning solutions; one example is tetramethylammonium hydroxide (TMAH). However, because this compound is known to be a transdermal toxin, the semiconductor manufacturing industry is interested in alternative alkaline compounds for use in cleaning solutions. Simultaneously, for surface-treating new microelectronic device substrates, such as those comprising copper, cobalt, or both, novel and suitable cleaning compositions with good cleaning performance and preferably low corrosiveness to exposed metals are needed. Summary of the Invention

[0014] There is a persistent need for compositions and methods suitable for removing residues from the surface of microelectronic device substrates within a process. This invention relates to such compositions, referred herein as “cleaning compositions,” such as “cleaning solutions.” Preferred compositions provide effective or highly effective self-cleaning and removal of residues from surfaces while inhibiting damage to the metallic characteristics of the surface (e.g., corrosion).

[0015] According to the invention, suitable cleaning compositions comprise a combination of an aqueous carrier (i.e., water) and non-aqueous components, said non-aqueous components including: alkali (to provide an alkaline pH), cleaning compounds, and corrosion inhibitors. The described compositions may also optionally contain any one or more of a variety of additional non-aqueous components suitable for removing residues from substrate surfaces, such as any one or more of the following: chelating agents, oxidizing agents, surfactants, buffers, biocides, organic solvents (e.g., low molecular weight alcohols, polyols), or any other trace components suitable for use in the described cleaning compositions. Preferred cleaning compositions are homogeneous solutions prior to use in the cleaning process, wherein all non-aqueous components are substantially dissolved in water (in solution form) and contain no suspended solid materials, such as solid abrasive particles.

[0016] The applicant has discovered that various compounds that effectively inhibit metal corrosion in cleaning compositions used for cleaning the surfaces of substrates of microelectronic devices, which were previously unknown, are actually used in a novel and inventive manner as corrosion inhibitors in these cleaning compositions and methods. Generally, suitable corrosion inhibitors of the present invention include guanidine functionalized additives, pyrazolone functionalized additives, and 8-hydroxyquinoline and related compounds. Certain more specific examples of compounds identified by the applicant as novel and inventive corrosion inhibitors in cleaning compositions include: 2-methyl-3-butyn-2-ol, 3-methyl-2-pyrazolone-5-one, 8-hydroxyquinoline, and dicyandiamide, any of which may be used alone (i.e., separately) or in combination in the cleaning composition.

[0017] In some embodiments, these corrosion inhibitors can be used in novel and inventive cleaning compositions that are not based on the presence of tetramethylammonium hydroxide (TMAH) as a base. TMAH is a common and effective base in cleaning compositions used in the semiconductor manufacturing industry, but it is currently disadvantageous due to its toxicity. Other bases are known and available, but they do not always match the effectiveness of TMAH in terms of cleaning efficacy and prevention of damage (e.g., corrosion) to metallic (e.g., copper) characteristics of the substrate surface. Therefore, there is a particular need for new cleaning solutions that do not require or do not contain TMAH and can provide cleaning efficacy and reduced corrosion performance comparable to or better than TMAH-containing cleaning solutions.

[0018] Therefore, this specification relates to cleaning compositions for use in cleaning processes of microelectronic device substrates, said compositions comprising water, an alkali (basic compound), a cleaning compound, and a corrosion inhibitor selected from: 2-methyl-3-butyn-2-ol, 3-methyl-2-pyrazol-5-one, dicyandiamide, 8-hydroxyquinoline, or combinations of two or more of these. Any or a combination of these corrosion inhibitors may be used or suitable with a variety of basic compounds, but is particularly desirable when used in cleaning compositions that do not contain TMAH as an alkali; alternative basic compounds suitable for certain example cleaning compositions include choline hydroxide, tetraethylammonium hydroxide, or combinations thereof.

[0019] The described cleaning compositions may include any of a variety of known cleaning compounds, with specific examples including alkanolamines as cleaning compounds. Alkanolamines may be any alkanolamine that is effective as a cleaning compound, including any primary, secondary, or tertiary amine. The alkanolamine will have at least one alkanol substituent (e.g., methanol, ethanol, etc.) and one, two, or three alkanol, alkyl, or alternative organic substituents. Some suitable alkanolamines are primary alkanolamines, such as monoethanolamine (MEA). The cleaning compositions may optionally contain additional cleaning compounds (i.e., "secondary" cleaning compounds), particularly, for example, morpholine, L-cysteine, hydroxyethyl cellulose, polyamines, and glycol ethers.

[0020] The described cleaning composition may include any of the following as corrosion inhibitors: various guanidine functional additives, such as dicyandiamide, metanilide, salts, guanidine salts, guanidinoacetic acid, and various pyrazolone functional additives, such as 2-methyl-3-butyn-2-ol, 3-methyl-2-pyrazol-5-one, such as 3-methyl-1-(4-sulfophenyl)-2-pyrazol-5-one or 3-methyl-1-p-tolyl-5-pyrazolone, and 8-hydroxyquinoline and related compounds, (8-hydroxyquinoline-2-carboxylic acid, 5-chloro-7-iodoquinoline-8-ol, 5,7-dichloro-2-[(dimethylamino)methyl)quinoline-8-ol, 8-hydroxyquinoline-4-carboxaldehyde, 8-hydroxyquinoline-4-carboxaldehyde-oxime, 8-hydroxyquinoline-5-sulfonic acid monohydrate) or combinations of two or more of these. Optionally, the composition may contain one or more additional corrosion inhibitors (i.e., one or more “secondary” corrosion inhibitors), such as secondary corrosion inhibitors particularly selected from oxalic acid, succinic acid, L-tartaric acid and combinations thereof.

[0021] According to preferred cleaning compositions and methods, certain cleaning compositions containing a corrosion inhibitor selected from dicyandiamide, 2-methyl-3-butyn-2-ol, 3-methyl-2-pyrazol-5-one, 8-hydroxyquinoline, or combinations of two or more of these may exhibit suitable or advantageous cleaning efficacy as described herein, combined with improved efficacy in reducing corrosion of metals (e.g., copper, cobalt, or both). Some examples of such cleaning compositions may also contain: choline hydroxide, tetraethylammonium hydroxide (TEAH), or both as a basic compound; and an alkanolamine (e.g., MEA) as a cleaning compound. During the cleaning process using such preferred compositions, for cleaning substrates containing exposed copper features (e.g., interconnects), cobalt features (e.g., barrier layers), or both, the amount of copper, cobalt, or both corrosion occurring during cleaning can be reduced compared to corrosion occurring using the same substrate and method. The cleaning composition is the same as before but does not contain various guanidine functional additives, such as dicyandiamide, formamidinium, salts, guanidine salts, guanidinoacetic acid, and various pyrazolone functional additives, such as 2-methyl-3-butyn-2-ol, 3-methyl-2-butyn-2-ol, etc. -Pyrazolin-5-one, such as 3-methyl-1-(4-sulfophenyl)-2-pyrazolin-5-one or 3-methyl-1-p-tolyl-5-pyrazolinone, and 8-hydroxyquinoline and related compounds (8-hydroxyquinoline-2-carboxylic acid, 5-chloro7-iodoquinoline-8-ol, 5,7-dichloro-2-[(dimethylamino)methyl)quinoline-8-ol, 8-hydroxyquinoline-4-carboxaldehyde, 8-hydroxyquinoline-4-carboxaldehyde-oxime, 8-hydroxyquinoline-5-sulfonic acid monohydrate) or combinations of two or more of these.

[0022] Alternatively or additionally, when compared with other known cleaning compositions using TMAH as an alkali, such preferred cleaning compositions as described can produce suitable cleaning results in the same method for cleaning the same substrate, wherein the amount of copper, cobalt, or both is relatively low; the amount of copper, cobalt, or both corrosion in the cleaning compositions and processes of the present invention can be the same as, or preferably reduced by at least 10%, 20%, 30%, or 40% (e.g., as measured as static etching rate) compared with the same process using TMAH-based cleaning compositions. A certain amount of corrosion caused by the cleaning composition can be measured by known and commercially available equipment and methods, including by performing known tests, such as tests of metal etching rates (e.g., static etching rates).

[0023] In a particular embodiment, the example cleaning composition contains aqueous and non-aqueous components comprising, consisting of, or substantially consisting of: an alkali (e.g., consisting of, or substantially consisting of: choline hydroxide, TEAH, TMAH, quaternary ammonium compounds, potassium hydroxide, or combinations thereof); a cleaning compound as described, such as an alkanolamine (e.g., consisting of, or substantially consisting of: MEA); and a corrosion inhibitor (e.g., as described, consisting of, or substantially consisting of: various guanidine functional additives, such as dicyandiamide, metformin, salts, guanidine salts, guanidinoacetic acid, and various pyrazolone functional additives). Agents, such as 2-methyl-3-butyn-2-ol, 3-methyl-2-pyrazolin-5-one, such as 3-methyl-1-(4-sulfophenyl)-2-pyrazolin-5-one or 3-methyl-1-p-tolyl-5-pyrazolinone, and 8-hydroxyquinoline and related compounds (8-hydroxyquinoline-2-carboxylic acid, 5-chloro7-iodoquinoline-8-ol, 5,7-dichloro-2-[(dimethylamino)methyl)quinoline-8-ol, 8-hydroxyquinoline-4-carboxaldehyde, 8-hydroxyquinoline-4-carboxaldehyde-oxime, 8-hydroxyquinoline-5-sulfonic acid monohydrate), can be used separately, in combination with each other, or in combination with one or more additional (e.g., "secondary") corrosion inhibitors.

[0024] As used herein, unless otherwise stated, a description of a composition or component as "consisting substantially of one or more of the specified items" means a composition or component consisting only of those specified items having no more than a non-significant amount of other (additional) materials, such as additional components containing only the specified items and not exceeding 5, 3, 2, 1, 0.5, 0.1, 0.05, or 0.01% by weight of the total weight of the composition or component. As used herein, a composition or component described as "consisting of one or more of the specified items" means a composition or component consisting only of those specified items.

[0025] Additionally, the composition may optionally include organic solvents, chelating agents, complexes, polymers, surfactants, or other components specific to the cleaning formulation.

[0026] As used herein, the term "residue" (including "contaminants") refers to any material that is a chemical or particulate material that remains on the surface of a microelectronic device substrate after processing steps used in the manufacture of the microelectronic device. Examples of processing steps include plasma etching, plasma ashing (to remove photoresist from a self-etched wafer), chemical mechanical processing, wet etching, etc. Residue can be any non-aqueous chemical substance that is part of the processing composition used in the processing steps, such as chemical etchants, photoresist, CMP slurries, etc. Residue may alternatively be a substance derived from the material of the processing composition during the processing steps. Examples of these types of residues include non-aqueous, particulate or non-particulate chemical or abrasive materials (e.g., abrasive particles, surfactants, oxidants, corrosion inhibitors, catalysts) that remain on the substrate surface after processing. Residue may initially be present in materials such as CMP slurries or etching compositions, such as solid abrasive particles or chemicals present in CMP abrasive slurries. Alternatively, residues may be byproducts or reaction products generated during processing (in particulate (e.g., agglomerates, precipitates) or non-particulate form), such as byproducts or reaction products of chemicals present in processing compositions such as CMP slurries or wet etching compositions, or chemicals present, used, or generated during plasma etching or plasma ashing processes.

[0027] The term "CMP post-processing residue" refers to residues present at the end of a CMP process step, such as particles or chemical materials present in or derived from the CMP slurry; specific examples include abrasive particles (e.g., silicon-containing or silicon-based abrasive particles, metal oxide (e.g., alumina) particles, cerium dioxide or cerium dioxide-based particles, etc.); chemicals initially present in the slurry, such as oxidants, catalysts, surfactants, inhibitors, chelating agents, etc.; metals (e.g., ions), metal oxides, or metal complexes derived from metallic materials removed from the treated substrate surface; or reaction products or complexes resulting from the use of slurry chemicals with another slurry chemical or with substrate-derived chemicals (e.g., metal ions; pad particles; or any other substance that is a product of the CMP process).

[0028] "Post-etching residue" refers to the material remaining after a vapor-phase plasma etching process, such as back-end-of-line (BEOL) dual damascene or wet etching. Post-etching residue can be organic, organometallic, organosilicon, or essentially inorganic, such as silicon-containing materials, carbon-based organic materials, and etching gas residues such as oxygen and fluorine.

[0029] "Post-ashing residue" refers to the material remaining after oxidative or reducing plasma ashing to remove hardened photoresist and / or bottom anti-reflective coating (BARC) material. Post-ashing residue can be organic, organometallic, organosilicon, or essentially inorganic.

[0030] As defined herein, a “low-k dielectric material” is any material used as a dielectric material in multilayer microelectronic devices, wherein the dielectric constant of the material is less than about 3.5. Examples of low-k dielectric materials include low-polarity materials such as silicon-containing organic polymers, silicon-containing hybrid organic-inorganic materials, organosilicate glass (OSG), TEOS, fluorinated silicate glass (FSG), and carbon-doped oxide (CDO) glass. Low-k dielectric materials can have densities and porosities within a suitable range of densities and porosities.

[0031] In one aspect, the present invention relates to a cleaning composition for cleaning substrates of microelectronic devices. The cleaning composition comprises: water; an alkali providing a pH of at least 8; a cleaning compound; and a corrosion inhibitor selected from guanidine functional compounds, pyrazolone functional compounds, and hydroxyquinoline compounds.

[0032] On the other hand, the present invention relates to a method for cleaning a substrate of a microelectronic device. The method includes: providing a cleaning composition as described; providing a microelectronic device substrate; and contacting the surface of the microelectronic device substrate with the cleaning composition. Attached Figure Description

[0033] Figures 1 to 3 Etching rate test data of the cleaning composition as described relative to non-inventive cleaning compositions are presented.

[0034] Figure 4 Electrochemical impedance test data are shown for the cleaning compositions as described, relative to non-inventive cleaning compositions. Detailed Implementation

[0035] This invention relates to compositions (“cleaning compositions” or “cleaning solutions”) suitable for cleaning methods to remove residues from the surface of microelectronic device substrates having residues. The described compositions are alkaline compositions containing a combination of an aqueous carrier (i.e., water) and non-aqueous components, said non-aqueous components including: alkali, cleaning compounds, and corrosion inhibitors. The described compositions may also optionally contain any one or more of a variety of non-aqueous components suitable for use in cleaning compositions, such as chelating agents, oxidizing agents, surfactants, buffers, biocides, organic solvents (e.g., low molecular weight alcohols, polyols), or any other trace components suitable for use in cleaning solutions as described. Preferably, the cleaning composition is a homogeneous solution containing water and dissolved non-aqueous components, consisting of water and dissolved non-aqueous components, or substantially consisting of water and dissolved non-aqueous components, prior to use in the cleaning method, in the absence of any solid or suspended matter such as solid abrasive particles, agglomerates, or flocculations.

[0036] The cleaning compositions described herein are suitable for cleaning microelectronic devices and their precursors, specifically including microelectronic device substrates, meaning semiconductor wafers comprising one or more microelectronic devices or their precursors on a surface, which are fabricated in processing into final, complete, and functional microelectronic devices. As used herein, a microelectronic device is a device comprising circuitry and associated structures formed thereon at extremely small (e.g., micrometer-scale or smaller) dimensions. Examples of microelectronic devices include flat panel displays, integrated circuits, memory devices, solar panels, photovoltaics, and microelectromechanical systems (MEMS). Microelectronic device substrates are, for example, wafer (e.g., semiconductor wafers) structures comprising one or more microelectronic devices or their precursors in a state ready to form a final microelectronic device.

[0037] The compositions and methods described herein are applicable to cleaning any type of microelectronic device at any stage of the process. A cleanable microelectronic device substrate with specific utility and benefits (or simply “substrate” herein, for brevity) includes a substrate whose surface includes exposed copper, cobalt, or both, for example, in the form of an exposed copper interconnect material or a cobalt barrier layer situated between an interconnect material and a dielectric or low-k dielectric material.

[0038] According to the present invention, the compositions can be used to clean these general and specific types of microelectronic device substrates to remove residues, such as (but not limited to) post-CMP residues, post-ashing residues, post-etching residues, or other residues present on the substrate surface after steps of processing the microelectronic device substrate. The cleaning compositions provide suitable or advantageous cleaning properties, meaning that the cleaning compositions can be used with known equipment (e.g., post-CMP cleaning equipment) to substantially reduce the amount of residues, contaminants, or both on the surface of the microelectronic device substrate. High percentages of residues present on the substrate surface can be successfully removed from the surface by using the cleaning compositions and methods described herein, for example, at least 70%, 80%, 85%, 90%, 95%, or 99% of the residues (also referred to as "cleaning efficiency").

[0039] Methods and apparatus for measuring residues on the surface of a microelectronic device substrate are well known. Cleaning effectiveness can be assessed based on the amount (e.g., number) of residue particles remaining on the microelectronic device surface reduced after cleaning, compared to the amount (e.g., number) of residue particles present before cleaning. For example, atomic force microscopy can be used for pre- and post-cleaning analysis. Residual particles on the surface can be recorded as pixel ranges. Histograms (e.g., Sigma Scan Pro) can be applied to filter pixels at an intensity of, for example, 231-235, and the number of residual particles can be counted. The amount of residue particles removed, i.e., cleaning efficiency, can be calculated using the following:

[0040] (Number of residual particles on the surface before cleaning - Number of residual particles on the surface after cleaning) / (Number of residual particles on the surface before cleaning).

[0041] Alternatively, cleaning effectiveness can be viewed as the percentage of the total amount of residual particulate matter covering the substrate surface before and after cleaning. For example, atomic force microscopy can be programmed to perform z-plane scans to identify areas of interest in the surface morphology above a certain height threshold, and then the total surface area covered by these areas can be calculated. After cleaning, a measured reduction in the area of ​​the region of interest indicates a more effective cleaning composition and method.

[0042] In addition to the excellent cleaning efficacy, cleaning methods, and cleaning compositions described, the cleaned substrate surface is also affected by exposed metal surfaces (e.g., exposed copper or exposed cobalt) subject to advantageous low-level corrosion. Examples of substrates that can be cleaned by such methods are substrates with copper or cobalt surfaces, for example in the form of metal interconnects (e.g., copper interconnects) or barrier layer materials (e.g., cobalt) situated between the metal interconnects and a dielectric or low-k dielectric material. Some examples of microelectronic device substrates from which cleaning yields particularly useful or advantageous results include those microelectronic device substrates with exposed structures on their surfaces comprising copper (e.g., copper or alloys thereof), cobalt (e.g., cobalt or alloys thereof), and a dielectric or low-k dielectric material. The corrosion inhibition of the cleaning composition can be reflected in measurements of the metal etching rate, such as the static etching rate, which can be performed using known methods and known equipment.

[0043] The compositions of this invention are those of the type referred to as "concentrates" or "concentrate compositions," and those referred to as "use compositions." Typically, cleaning compositions (e.g., solutions) are prepared and subsequently sold as concentrates containing a relatively low amount of water and therefore a relatively concentrated amount of non-aqueous components. Concentrates are commercially prepared for sale and transport while containing a concentrated amount of non-aqueous components and a relatively reduced amount of water, and are ultimately diluted by the purchaser of the concentrate upon use. The amounts of different non-aqueous components in the concentrate are those amounts of non-aqueous components that, upon dilution of the concentrate, would result in the desired amount being present in the use composition.

[0044] The cleaning composition described includes water as a liquid carrier of a non-aqueous component, preferably a solute. The water may preferably be deionized (DI) water. Water may be present in the composition from any source, for example: as a component (e.g., alkali, cleaning compound, corrosion inhibitor) contained in a composition combined with other components to produce a concentrate; or as pure water combined with other components of the concentrate; or as water added by the user to the concentrate during use, for the purpose of diluting the concentrate to form the composition for use.

[0045] The amount of water in the composition may be the desired amount of the concentrate or the desired amount of the composition used, and is generally a higher total amount relative to the amount of water in the concentrate. The amount of water in the concentrate composition is not considered limiting and may be from about 30, 40, or 50 to about 85 or 90% by weight, for example, from about 60, 65, or 70 to about 80% by weight of water, based on the total weight of the concentrate composition. Upon dilution, these amounts will be reduced by a dilution factor. The amount of water in the composition used, based on the total weight of the composition used, may be from about 75 to about 95% by weight, for example, from about 82 or 85 to about 90 or 93% by weight of water.

[0046] The composition includes an alkali (also referred to as an "alkaline compound") of a type and amount effective in increasing the pH of the cleaning composition during use to at least about 8, 9, or 10, for example, to a pH in the range of about 10 to about 12, 13, or 14. As specified, the alkali can be any alkali suitable for controlling the pH of the composition in use, wherein many different alkaline compounds are known for use in cleaning solutions suitable for cleaning surfaces of microelectronic device substrates, for example, as post-CMP cleaning solutions.

[0047] Non-limiting examples of basic compounds include: choline hydroxide, tetrabutylphosphonium hydroxide (TBPH), tetramethylphosphonium hydroxide, tetraethylphosphonium hydroxide, tetrapropylphosphonium hydroxide, benzyltriphenylphosphonium hydroxide, methyltriphenylphosphonium hydroxide, ethyltriphenylphosphonium hydroxide, N-propyltriphenylphosphonium hydroxide, tetraethylammonium hydroxide (TEAH), tetrapropylammonium hydroxide (TPAH), tetrabutylammonium hydroxide (TBAH), trimethylethylammonium hydroxide, diethyldimethylammonium hydroxide, tributylmethylammonium hydroxide (TBMAH), benzyltrimethylammonium hydroxide (BTMAH), tetramethylammonium hydroxide (TMAH), tris(2-hydroxyethyl)methylammonium hydroxide, diethyldimethylammonium hydroxide, guanidine acetate, 1,1,3,3-tetramethylguanidine, guanidine carbonate, arginine, potassium hydroxide, cesium hydroxide, and combinations thereof.

[0048] Examples of certain preferred alkaline compounds of the invention for use in cleaning compositions as described, in combination with the novel and corrosion inhibitors of the invention, are choline hydroxide and tetraethylammonium hydroxide (TEAH). These alkaline compounds may be included individually (e.g., alone) as the only alkaline compound in the composition; combined with each other in the composition, i.e., as the only two alkaline compounds in the composition; or (alone or in combination with each other) combined with one or more additional (e.g., secondary) bases in the composition.

[0049] Certain particularly preferred cleaning compositions comprise an alkali consisting of or substantially consisting of choline hydrochloride, tetraethylammonium hydroxide (TEAH), potassium hydroxide, or combinations thereof. Alternatively, and more generally, other examples of the described cleaning compositions may include choline hydroxide, tetraethylammonium hydroxide (TEAH), potassium hydroxide, or combinations thereof, combined with one or more additional alkalis other than choline hydroxide, potassium hydroxide, and tetraethylammonium hydroxide (TEAH). Certain preferred cleaning compositions of this kind may preferably contain no more than an insignificant amount of tetramethylammonium hydrochloride (TMAH). Cleaning compositions containing an alkali consisting essentially of choline hydrochloride, tetraethylamine hydroxide, potassium hydroxide, or combinations thereof substantially exclude the presence of any other alkali (e.g., as listed above, especially tetramethylammonium hydrochloride (TMAH)) in the cleaning composition, and will contain choline hydrochloride, tetraethylamine hydroxide, or combinations thereof as essentially the only alkali or multiple alkalis in the composition; examples of this type of cleaning composition in concentrate form may contain no more than 1, 0.5, 0.1, 0.05, or 0.001% by weight of TMAH based on the total weight of the concentrate; examples in use composition form may contain no more than 0.5 or 0.3% by weight of TMAH based on the total weight of the use composition, for example, no more than 0.1, 0.05, 0.03, 0.01, 0.005, or 0.0005% by weight of TMAH based on the total weight of the use composition.

[0050] The amount of alkali included in the cleaning composition (measured as a non-aqueous solid) may depend on the type of alkali (or multiple alkalis) and may be the total amount of alkali that will produce the desired pH (e.g., at least 8, 9 or 10 in the composition, such as in the range of about 10 to 14, 10 to 13 or 10 to 12) after dilution to the composition for use.

[0051] When measured in non-aqueous form, that is, in the form of the "solid" chemical composition of the alkali (including all components of the alkaline compound, such as hydroxide anions of an alkaline compound including hydroxide ions), the example cleaning composition may contain about 3 to 95 parts by weight (pbw) of total alkali (solid, such as choline hydroxide, TEAH, potassium hydroxide or combinations thereof), for example, the total amount of the following substances per 100 parts by weight is 5 to 70 or 90 pbw alkali: alkali (all types), cleaning compound (all types), and corrosion inhibitor (all types) of the composition (these relative amounts of alkali are based on the three specified non-aqueous components in 100 parts by weight of the composition, regardless of the presence or amount of any water in the composition, and are the same on a relative basis whether the cleaning composition is a concentrate or a used composition).

[0052] In other words, the example composition may contain a total of about 3 to 95, for example 5 to 70 or 90 parts by weight (pbw) of base (e.g., choline hydroxide, TEAH, potassium hydroxide or combinations thereof) per 100 parts by weight of the composition, the non-aqueous component of which includes base (all types), cleaning compound (all types), corrosion inhibitor (all types) and any other optional components present in the composition (e.g., chelating agents, oxidizing agents, surfactants, buffers, organic solvents, etc.).

[0053] Examples of suitable and preferred amounts of alkali (non-aqueous "solid" alkali material) may be described in alternative terms as a weight percentage of the total weight of the cleaning composition, wherein the relevant percentage of the component may differ for a concentrate composition (which will have a relatively high amount of non-aqueous component) compared to a use composition (which will have a relatively low amount of non-aqueous component). In terms of weight percentage, certain examples of concentrate compositions described in this invention may comprise about 3 to 60% by weight of alkali per concentrate composition. Certain examples of use compositions may comprise about 0.4 to 10% by weight of alkali per use composition, for example, 0.6 to 8%, or 0.7 to 4, 5, or 6% by weight of alkali.

[0054] The cleaning composition described herein also includes a cleaning compound. The cleaning compound may be a compound that effectively enhances the cleaning ability (e.g., efficacy, efficiency, etc.) of the cleaning composition, for example by acting as a solvent that promotes the removal of residues from the substrate surface, by dissolving the residues, by forming a complex with the residues, or by otherwise chemically interacting with the residues to allow the residues to be removed from the substrate surface to be cleaned.

[0055] As needed, the cleaning composition may include a single type of cleaning compound or a combination of two or more different types of cleaning compounds. The type and amount of one or more cleaning compounds may be any compound that will result in the desired effectiveness of the composition (e.g., good cleaning and acceptable or favorable levels of corrosion resistance, low levels of defects, etc.) and may preferably also produce a concentrate exhibiting suitable effectiveness and stability properties.

[0056] As a cleaning compound, the example cleaning compositions of this specification may include alkanolamines. Alkanolamines are compounds comprising an amine group substituted with at least one alkyl alcohol group. Alkanolamines can be any alkanolamine effective as a cleaning compound as described, including primary, secondary, and tertiary amine compounds. Alkanolamine compounds will have at least one alkyl alcohol substituent (e.g., methanol, ethanol, etc.) and one, two, or three alkyl alcohol, alkyl, or substituted organic substituents. Some applicable alkanolamines are primary alkanolamines, such as monoethanolamine (MEA), aminoethylethanolamine, N-methylaminoethanol, aminoethoxyethanol, aminoethoxyethoxyethanol, butoxypropylamine, methoxypropylamine, butoxyisopropylamine, 2-ethylhexylisopropoxyamine, ethanolpropylamine, ethylethanolamine, n-hydroxyethylmorpholine, aminopropyl diethanolamine, dimethylaminoethoxyethanol, diethanolamine, N-methyldiethanolamine, monoethanolamine, triethanolamine, 1-amino-2-propanol, 3-amino-1-propanol, diisopropylamine, aminomethylpropylene glycol, N,N-dimethylaminomethylpropylene glycol, and aminoethylpropylene glycol. N,N-Dimethylaminoethylpropanediol, isopropylamine, 2-amino-1-butanol, aminomethylpropanol, aminodimethylpropanol, N,N-dimethylaminomethylpropanol, isobutanolamine, diisopropanolamine, 3-amino,4-hydroxyoctane, 2-aminobutanol, tris(hydroxymethyl)aminomethane (TRIS), N,N-dimethyltris(hydroxymethyl)aminomethane, hydroxypropylamine, benzylamine, hydroxyethylamine, tris(hydroxyethyl)aminomethane, triethylenediamine, tetraethylenepentamine (TEPA), triethylenetetramine, ethylenediamine, hexamethylenediamine, diethylenetriamine, triethylamine, trimethylamine, diethylene glycolamine; morpholine and combinations thereof.

[0057] Optionally, the composition may contain an alkanolamine as a cleaning compound and additional (i.e., "secondary") cleaning compounds. Examples include organic solvents, water-soluble polymers, or surfactants. The secondary cleaning compound can be any compound included in the cleaning composition as an effective cleaning compound in combination with other components. Some specific examples of secondary cleaning compounds include: morpholine, L-cysteine, hydroxyethyl cellulose, polyamines, glycol ethers (e.g., propylene glycol n-butyl ether), alginate and its salts; carboxymethyl cellulose; dextran sulfate and its salts; poly(galacturonic acid) and its salts; homopolymers of (meth)acrylic acid and its salts, maleic acid, maleic anhydride, styrene sulfonic acid and its salts, vinyl sulfonic acid and its salts, allyl sulfonic acid and its salts, acrylamidopropyl sulfonic acid and its salts; (meth)acrylic acid and its salts, maleic acid, maleic anhydride, styrene sulfonic acid and its salts, vinyl sulfonic acid and its salts, allyl sulfonic acid and its salts, acrylamidopropyl sulfonic acid and its salts; poly(galacturonic acid) ... Glucosamine sugar; cationic starch; copolymers of polylysine and its salts; diallyl dimethyl ammonium chloride (DADMAC), diallyl dimethyl ammonium bromide, diallyl dimethyl ammonium sulfate, diallyl dimethyl ammonium phosphate, dimethylallyl dimethyl ammonium chloride, diethylallyl dimethyl ammonium chloride, diallyl di(β-hydroxyethyl) ammonium chloride, diallyl di(β-ethoxyethyl) ammonium chloride, addition salts and quaternary salts of (meth)acrylate dimethylaminoethyl ester, addition salts and quaternary salts of (meth)acrylate diethylaminoethyl ester, addition salts and quaternary salts of (meth)acrylate 7-amino-3,7-dimethyloctyl ester, N,N'-dimethylaminopropylacrylamide Homopolymers of addition salts and quaternary salts, allylamine, diallylamine, ethyleneamine, and vinylpyridine; and diallyl dimethylammonium chloride (DADMAC), diallyl dimethylammonium bromide, diallyl dimethylammonium sulfate, diallyl dimethylammonium phosphate, dimethylallyl dimethylammonium chloride, diethylallyl dimethylammonium chloride, diallyl di(β-hydroxyethyl)ammonium chloride, diallyl di(β-ethoxyethyl)ammonium chloride, addition salts and quaternary salts of (meth)acrylate dimethylaminoethyl ester, addition salts and quaternary salts of (meth)acrylate diethylaminoethyl ester, addition salts and quaternary salts of (meth)acrylate 7-amino-3,7-dimethyloctyl ester, N,N'-di Copolymers of methylaminopropylacrylamide addition salts and quaternary salts, allylamine, diallylamine, ethyleneamine, and vinylpyridine; cocodimethylcarboxymethyl betaine; lauryldimethylcarboxymethyl betaine; lauryldimethyl-α-carboxyethyl betaine; hexadecyldimethylcarboxymethyl betaine; lauryl-bis-(2-hydroxyethyl)carboxymethyl betaine; stearyl-bis-(2-hydroxypropyl)carboxymethyl betaine; oleoyldimethyl-γ-carboxypropyl betaine; lauryl-bis-(2-hydroxypropyl)α-carboxyethyl betaine; cocodimethylsulfopropyl betaine; stearyldimethylsulfopropyl betaine; lauryl-bis-(2-hydroxyethyl)sulfopropyl betaine;Sodium dodecyl sulfate; Sodium dioctyl sulfosuccinate; Sodium lauryl ether sulfate; Polyethylene glycol branched-nonylphenyl ether ammonium sulfate; Disodium 2-dodecyl-3-(2-sulfonylphenoxy)-2-carboxymethyl ether; PEG25-PABA; Sodium mono-C10-16-alkyl ether sulfate; (2-N-butoxyethoxy)acetic acid; Hexadecylbenzenesulfonic acid; Cetyltrimethylammonium hydroxide; Dodecyltrimethylammonium hydroxide; Dodecyltrimethylammonium chloride; Cetyltrimethylammonium chloride Wax-based trimethylammonium; N-alkyl-N-benzyl-N,N-dimethylammonium chloride; dodecylamine; polyoxyethylene lauryl ether; dodecanoic acid monodiethanolamide; tetra(ethoxy-block-propoxy)ethylenediamine; 2-pyrrolidone; 1-(2-hydroxyethyl)-2-pyrrolidone (HEP); glycerol; 1,4-butanediol; tetramethylene sulfone (sulfolane); dimethyl sulfone; ethylene glycol; propylene glycol; dipropylene glycol; tetraethylene glycol dimethyl ether; diethylene glycol dimethyl ether. Glycol ethers (e.g., diethylene glycol monomethyl ether, triethylene glycol monomethyl ether, diethylene glycol monoethyl ether, triethylene glycol monoethyl ether, ethylene glycol monopropyl ether, ethylene glycol monobutyl ether, diethylene glycol monobutyl ether (DEGBE), triethylene glycol monobutyl ether (TEGBE), ethylene glycol monohexyl ether (EGHE), diethylene glycol monohexyl ether (DEGHE), ethylene glycol phenyl ether, propylene glycol methyl ether, dipropylene glycol methyl ether (DPGME), tripropylene glycol methyl ether (TPGME), dipropylene glycol dimethyl ether, dipropylene glycol ethyl ether, propylene glycol n-propyl ether, dipropylene glycol n-propyl ether (DPGPE), tripropylene glycol n-propyl ether, propylene glycol n-butyl ether (DOWANOL PnB), dipropylene glycol n-butyl ether, tripropylene glycol n-butyl ether, propylene glycol phenyl ether (DOWANOL PPh)) and combinations thereof.

[0058] Alternatively or additionally, the cleaning composition may include organic additives selected from: phosphonic acids and their derivatives, such as 1-hydroxyethylidene-1,1-diphosphonic acid (HEDP), 1,5,9-triazacyclododecane-N,N',N''-tris(methylenephosphonic acid) (DOTRP), 1,4,7,10-tetraazacyclododecane-N,N',N'',N'''-tetra(methylenephosphonic acid) (DOTP), azoxytris(methylene)triphosphonic acid, diethylenetriaminepenta(methylenephosphonic acid) (DETAP), aminotris(methylenephosphonic acid), bis(hexamethylene)triaminephosphonic acid, 1,4,7-triazacyclononane-N,N',N''-tris(methylenephosphonic acid) (NOTP), their salts and their derivatives.

[0059] Alternatively or additionally, the cleaning composition may include organic additives selected from: hydroxypropyl cellulose, hydroxyethyl cellulose, carboxymethyl cellulose, sodium carboxymethyl cellulose (Na CMC), polyvinylpyrrolidone (PVP), any polymer made using N-vinylpyrrolidone monomer, polyacrylates and polyacrylate analogs, polyamino acids (e.g., polyalanine, polyleucine, polyglycine), polyamide hydroxylamine carbamate, polylactone, polyacrylamide, succinate, polyglucosamine, polyethylene oxide, polyvinyl alcohol (PVA), polyvinyl acetate, polyacrylic acid, polyethylenediimide (PEI), sugar alcohols (e.g., sorbitol and xylitol), esters of dehydrosorbitol, secondary alcohol ethoxylates (e.g., TERGITOL), and combinations thereof.

[0060] In a preferred embodiment, at least one organic additive comprises HEDP. In another preferred embodiment, at least one organic additive comprises at least one glycol ether, which comprises triethylene glycol monobutyl ether, propylene glycol n-butyl ether, or propylene glycol phenyl ether. In another preferred embodiment, at least one organic additive comprises HEDP and at least one glycol ether comprising triethylene glycol monobutyl ether, propylene glycol n-butyl ether, or propylene glycol phenyl ether. In another preferred embodiment, at least one organic additive comprises HEC or a combination of HEDP and HEC, or a combination of HEC, HEDP, and at least one glycol ether comprising triethylene glycol monobutyl ether, propylene glycol n-butyl ether, or propylene glycol phenyl ether, or a combination thereof.

[0061] The cleaning composition may include any applicable amount of cleaning compounds, such as alkanolamines, and optional secondary cleaning compounds, such as one or more of those compounds specifically listed herein. For example, the cleaning composition may contain about 0.01 or 80 parts by weight (pbw) of total cleaning compounds (of any type), such as 0.02 to 70 pbw of the following total amounts per 100 parts by weight: the base of the composition (all types), the cleaning compound (all types), and the corrosion inhibitor (all types). (These relative amounts of cleaning compounds are based on the three specific components in 100 parts by weight of the composition and are independent of the presence or amount of any water in the composition, and are the same on a relative basis whether the cleaning composition is a concentrate or a used composition).

[0062] In alternative terms, the example composition may contain about 0.01 to 80, for example 0.02 to 40 parts by weight (pbw) of non-aqueous components (e.g., alkalis (all types), cleaning compounds (all types), corrosion inhibitors (all types), and optional components (e.g., chelating agents, oxidants, surfactants, buffers, organic solvents, etc.) per 100 parts by weight of the composition.

[0063] In terms of weight percentage, certain example compositions may contain about 0.01 to 80% by weight of a cleaning compound (of all types) per total weight of the concentrate composition, for example, about 0.02 to 70% by weight of a cleaning compound. Certain example uses compositions may include about 0.01 to 4% by weight of a cleaning compound per total weight of the uses composition, for example, 0.02 to 4% by weight of a cleaning compound.

[0064] Consistent with the above, certain preferred examples of cleaning compositions contain an alkanolamine (e.g., MEA) as a cleaning compound, and one or more secondary cleaning compounds, such as one or more of those specifically identified herein. Such cleaning compositions may comprise about 0.5 to 20 parts by weight (pbw) of alkanolamines per 100 parts by weight of each of the following: an alkanolamine base (all types), a cleaning compound (all types), and a corrosion inhibitor (all types).

[0065] Alternatively, the example composition may contain about 0.3 to 5, for example 0.4 to 4 parts by weight (pbw) of non-aqueous components (e.g., bases (all types), cleaning compounds (all types), corrosion inhibitors (all types) and optional components (e.g., chelating agents, oxidizing agents, surfactants, buffers, organic solvents, etc.) per 100 parts by weight of the composition.

[0066] In terms of weight percentage, these example compositions comprising alkanolamines and one or more secondary cleaning compounds may contain about 0.5 to 5% by weight of alkanolamines per concentrate composition, for example, about 0.7 to 3% by weight of alkanolamines. Some example compositions may include about 0.05 to 3% by weight of alkanolamines per use composition, for example, 0.07 to 2.5% by weight of alkanolamines and secondary cleaning compounds.

[0067] Certain example compositions may contain a cleaning compound consisting of or substantially consisting of an alkanolamine (e.g., MEA) and optional secondary cleaning compounds selected from morpholine, L-cysteine, hydroxyethyl cellulose, polyamines, glycol ethers, and combinations thereof. The composition contains a cleaning compound substantially consisting of an alkanolamine (e.g., MEA) and optional secondary cleaning compounds selected from morpholine, L-cysteine, hydroxyethyl cellulose, polyamines, glycol ethers, or combinations thereof. The composition is a composition containing only an alkanolamine (e.g., MEA) and one or more of the listed optional secondary cleaning compounds, wherein any other cleaning compound has a weight percentage not exceeding 0.5, 0.1, 0.05, or 0.01% by weight of the total weight of the cleaning compounds or organic cleaning additives in the compositions listed in the previous description.

[0068] The cleaning composition described herein also includes a metal corrosion inhibitor (i.e., a "corrosion inhibitor"), which is any compound that reduces the amount (e.g., rate) of corrosion of the metal on the substrate surface that occurs during cleaning of the substrate using the cleaning composition. According to the invention, the cleaning composition described herein includes a corrosion inhibitor selected from: various guanidine-functionalized additives, such as dicyandiamide, galegene, metformin, metformin salts (phosphates, sulfates, chlorides, nitrates, dinitramines), guanidines and guanidine salts (sulfates, carbonates, chlorides, acetates, lactates, nitrates, phosphates, thiocyanates), 1-methylguanidine sulfate, arginine, methylarginine, arginaminosuccinic acid, β-guanidinopropionic acid, triazabicyclododecyl-5-ene, creatine, creatinine, benzylaminopyridinium chloride, cariporide, and gualfacine. Biguanide, guanidinoacetic acid; various pyrazolone functional additives, such as 2-methyl-3-butyn-2-ol, 3-methyl-2-pyrazol-5-one, such as 3-methyl-1-(4-sulfophenyl)-2-pyrazol-5-one or 3-methyl-1-p-tolyl-5-pyrazolone; and hydroxyquinoline compounds, such as 8-hydroxyquinoline and related compounds (8-hydroxyquinoline-2-carboxylic acid, 5-chloro-7-iodoquinoline-8-ol, 5,7-dichloro-2-[(dimethylamino)methyl)quinoline-8-ol, 8-hydroxyquinoline-4-carboxaldehyde, 8-hydroxyquinoline-4-carboxaldehyde-oxime, 8-hydroxyquinoline-5-sulfonic acid monohydrate) and combinations thereof.

[0069] Dicyandiamide is a known compound having the following formula:

[0070]

[0071] Dicyandiamide, also known as 2-cyanoguanidine and dicyanodiamide, can be prepared by known methods of treating cyanamide with alkali and is commercially available. The compound 2-methyl-3-butyn-2-ol (also known as dimethylpropynyl alcohol (CAS number 115-19-5)) is also commercially available, as is the compound 3-methyl-2-pyrazolin-5-one (CAS number 108-26-9). Arginine has CAS numbers 7200-25-1 & 74-79-3.

[0072] Any of these corrosion inhibitor compounds may be used in a cleaning composition, either in any suitable combination of two or more identified corrosion inhibitor compounds (e.g., with each other), or may be used alone or in any suitable combination with one or more other (e.g., "secondary") corrosion inhibitors. Examples of suitable secondary corrosion inhibitors should not be construed as limiting the invention to these secondary corrosion inhibitors, including oxalic acid, succinic acid, L&+-tartaric acid, citric acid, and combinations thereof.

[0073] The cleaning composition described may include any suitable amount of corrosion inhibitor (“inhibitor”), such as dicyandiamide, 2-methyl-3-butyn-2-ol, 3-methyl-2-pyrazol-5-one, arginine, etc., said corrosion inhibitor alone or in combination, together with any optional secondary inhibitor (such as one or more of those inhibitors specifically listed herein). For example, the cleaning composition may contain about 0.1 or 0.5 to 1 or 4 parts by weight (pbw) of total corrosion inhibitor (of any type) per 100 parts by weight, such as 0.5 to 4 pbw corrosion inhibitor: base (of all types), cleaning compound (of all types), and corrosion inhibitor (of all types) of the composition.

[0074] In alternative terms, the example composition may contain a total amount of about 0.01 or 0.3 to 1 or 2, for example 0.05 to 1.5 or 2 parts by weight (pbw) of non-aqueous components (e.g., alkalis (all types), cleaning compounds (all types), corrosion inhibitors (all types) and optional components (e.g., chelating agents, oxidants, surfactants, buffers, organic solvents, etc.) per 100 parts by weight of the composition.

[0075] In terms of weight percentage, certain example compositions described in this invention may include about 0.05 to 4% by weight of corrosion inhibitor (of all types) per total weight of concentrate composition, such as about 0.08 to 3% by weight of corrosion inhibitor. Certain example compositions may include about 0.01 to 3% by weight of inhibitor per total weight of the composition used, such as 0.01 to 1.5 or 2% by weight of corrosion inhibitor.

[0076] Consistent with the above, certain preferred examples of cleaning compositions contain at least one of dicyandiamide, 2-methyl-3-butyn-2-ol, and 3-methyl-2-pyrazolin-5-one, or combinations thereof, as a corrosion inhibitor, in combination with one or more secondary corrosion inhibitors (e.g., one of those corrosion inhibitors specifically identified herein). Such cleaning compositions may include, for example, amounts of dicyandiamide, 2-methyl-3-butyn-2-ol, 3-methyl-2-pyrazolin-5-one, or combinations thereof, in amounts totaling about 0.4 to 6 parts by weight (pbw) per 100 parts by weight, such as 0.6 to 6 pbw: the base of the composition (all types), the cleaning compound (all types), and the corrosion inhibitor (all types).

[0077] Another version states that the example composition may contain about 0.25 to 5 parts by weight of the total amount of non-aqueous components (e.g., bases (all types), cleaning compounds (all types), corrosion inhibitors (all types) and optional components (e.g., chelating agents, oxidizing agents, surfactants, buffers, organic solvents, etc.) per 100 parts by weight of the composition, such as 0 to 4 parts by weight (pbw) of dicyandiamide, 2-methyl-3-butyn-2-ol and 3-methyl-2-pyrazolin-5-one or combinations thereof.

[0078] In weight percentage, these exemplary compositions (including dicyandiamide, 2-methyl-3-butyn-2-ol, 3-methyl-2-pyrazolin-5-one, or combinations thereof) may contain about 0.05 to 1.5% by weight of dicyandiamide, 2-methyl-3-butyn-2-ol, 3-methyl-2-pyrazolin-5-one, or combinations thereof per concentrate composition, for example, about 0.07 to 1% by weight of dicyandiamide, 2-methyl-3-butyn-2-ol, or 3-methyl-2-pyrazolin-5-one, or combinations thereof. Some examples of compositions may include about 0.005 to 1% by weight of dicyandiamide, 2-methyl-3-butyn-2-ol, or 3-methyl-2-pyrazolin-5-one, or combinations thereof per total weight of the composition used, for example, 0.007 to 0.8% by weight of dicyandiamide, 2-methyl-3-butyn-2-ol, or 3-methyl-2-pyrazolin-5-one, or combinations thereof.

[0079] These and other example cleaning compositions may contain corrosion inhibitors consisting of or substantially consisting of dicyandiamide, 2-methyl-3-butyn-2-ol, 3-methyl-2-pyrazol-5-one, or combinations thereof, optionally combined with a secondary corrosion inhibitor selected from oxalic acid, succinic acid, L-tartaric acid, and combinations thereof. A composition containing a corrosion inhibitor substantially consisting of dicyandiamide, 2-methyl-3-butyn-2-ol, or 3-methyl-2-pyrazol-5-one, or combinations thereof, optionally combined with a secondary corrosion inhibitor selected from oxalic acid, succinic acid, L-tartaric acid, and combinations thereof, is a composition comprising only those specified corrosion inhibitors (and optional corrosion inhibitors) and any other corrosion inhibitors not exceeding 0.5, 0.1, 0.005, or 0.01% by weight of the total corrosion inhibitors in the composition.

[0080] Consistent with the foregoing, examples of certain cleaning compositions may consist of or consist substantially of water, alkali (e.g., selected from those specifically mentioned herein), cleaning compounds (e.g., selected from those specifically mentioned herein), and corrosion inhibitors (e.g., selected from those specifically listed herein). Compositions consisting substantially of water, alkali, cleaning compounds, and corrosion inhibitors as described may contain those components in amounts not exceeding 0.5, 0.1, 0.05, or 0.01% by weight of any other components.

[0081] In preferred compositions, the combination of corrosion inhibitors with other components of the cleaning composition produces compositions that, overall, produce the desired, useful, or advantageous cleaning performance of the cleaning composition, and reduce metal corrosion (e.g., reduced corrosion of exposed copper, cobalt, or both) compared to corrosion occurring with the use of equivalent cleaning compositions (e.g., other equivalent cleaning compositions without the corrosion inhibitors of this invention).

[0082] Optionally, in addition to water, alkali, cleaning composition (as described), and corrosion inhibitor, the cleaning composition may also optionally include other non-particulate, non-aqueous chemical components dissolved in the composition and capable of improving the cleaning effect or other performance characteristics of the composition. Examples of such optional components include certain types of components known in semiconductor processing, manufacturing, and cleaning techniques, including post-CMP cleaning. These components include those generally understood to improve the performance (e.g., cleaning effect) of the cleaning composition in any mode; example materials can generally be considered as cleaning compounds, corrosion inhibitors, or alkalis (as used herein) and can be more specifically characterized according to chemical functional groups, such as as: chelating agents (e.g., “uncoupling agents”), oxidizing agents, surfactants, buffers (pH buffers), biocides, organic solvents, etc.

[0083] The term "sequestering agent" is used herein in accordance with its usage in semiconductor processing and cleaning techniques (e.g., post-CMP cleaning) and refers to chemical sequestering agents, chelating agents, and sequestering agents. Sequestering agents are known to be compounds that chemically sequester or physically immobilize (sequester) metal atoms or ions during the process of using a cleaning composition as described herein to remove residues from the surface of a microelectronic device. These agents may include acetic acid, acetone oxime, acrylic acid, adipic acid, alanine, arginine, asparagine, aspartic acid, betaine, diethyl ketone, formic acid, fumaric acid, gluconic acid, glutamic acid, glutamyl glutamate, glutamate, glutamate, glutamic acid, glyceric acid, glycerol, glycolic acid, glyoxylic acid, histidine, iminodiacetic acid, isophthalic acid, itaconic acid, lactic acid, leucine, lysine, maleic acid, maleic anhydride, malic acid, etc. Malonic acid, mandelic acid, 2,4-pentanedione, phenylacetic acid, phenylalanine, phthalic acid, proline, propionic acid, catechol, benzopyrenic acid, quinic acid, serine, sorbitol, succinic acid, tartaric acid, terephthalic acid, trimellitic acid, pyromellitic acid, tyrosine, valine, xylitol, oxalic acid, tannic acid, pyridinecarboxylic acid, 1,3-cyclopentanedione, catechol, pyrogallol, resorcinol, hydroquinone, cyanuric acid Barbiturate, 1,2-dimethylbarbituric acid, pyruvic acid, propanethiol, benzo[a]hydroxamic acid, 2,5-dicarboxypyridine, 4-(2-hydroxyethyl)morpholine (HEM), N-aminoethylpiperazine (N-AEP), ethylenediaminetetraacetic acid (EDTA), 1,2-cyclohexanediamine-N,N,N',N'-tetraacetic acid (CDTA), N-(hydroxyethyl)-ethylenediaminetriacetic acid (HEdTA), iminodiacetic acid (IDA), 2-(hydroxyethyl)iminodiacetic acid (HIDA), azotriacetic acid, thiourea, 1,1,3,3-tetramethylurea, urea, urea derivatives, glycine, cysteine, glutamic acid, isoleucine, methionine, piperidine, N-(2-aminoethyl)piperidine, pyrrolidine, threonine, tryptophan, salicylic acid, p-toluenesulfonic acid, salicylic acid, 5-sulfosalicylic acid, and combinations thereof.

[0084] The terms "oxidizer" and "oxidizing agent" are used herein in a manner consistent with their use in semiconductor processing and cleaning techniques, such as post-CMP cleaning. Examples of oxidizing agents include inorganic and organic peroxides, comprising compounds containing at least one peroxy group (-O--O-) and compounds containing an element in its highest oxidation state. Examples include hydrogen peroxide and its adducts, such as urea peroxide and percarbonate; organic peroxides, such as benzoyl peroxide, peracetic acid, and di-tert-butyl peroxide; and disperoxysulfate (S₂O₈). =); monopersulfate (SO5) = Sodium persulfate; periodate; perbromic acid; periodic acid; perbromic acid; perchloric acid; perchlorate; perboric acid; perborate; and permanganate.

[0085] As used herein, the term "surfactant" is used in a manner consistent with its application in chemical, semiconductor processing, and semiconductor cleaning techniques (e.g., post-CMP cleaning). In accordance with this, a "surfactant" is an organic compound that reduces the surface tension (or interfacial tension) between two liquids or between a liquid and a solid, typically an amphiphilic organic compound containing both a hydrophobic group (e.g., a hydrocarbon (e.g., an alkyl "tail")) and a hydrophilic group.

[0086] Therefore, in addition to the alkali compounds, cleaning compounds, and corrosion inhibitors specifically identified herein, cleaning compositions may include additional ingredients suitable for improving performance. These ingredients are sometimes referred to as chelating agents (“chelating agents”), oxidizing agents, surfactants, buffers, biocides, organic solvents, and other minor ingredients of suitable types. Alternatively, certain embodiments of the compositions in this specification may avoid, specifically exclude, or use only small amounts of ingredients different from the alkali compounds, cleaning compounds, and corrosion inhibitors specifically identified herein. Example compositions may include no more than a limited or insignificant amount of any of these non-aqueous ingredients (different from the alkali compounds, cleaning compounds, or corrosion inhibitors specifically identified herein), for example, less than 1, 0.1, 0.05, 0.01, or 0.001% by weight of any such compound based on the total weight of the composition (concentrate or used composition).

[0087] The cleaning composition is suitable for removing residues from a substrate surface without intending to remove any substantial material from the substrate surface itself, such as that present in the presence of chemical or abrasive materials in a CMP slurry during a chemical mechanical processing step. Therefore, the cleaning composition described excludes any amount of solid abrasive particles that would effectively mechanically (by abrasion) remove material constituting the substrate surface (as opposed to residues present on the surface). Examples of such excluded abrasive particles are well known in CMP and semiconductor processing technologies and include solid (undissolved) particles made of or containing materials including: metals and metal oxides (e.g., aluminum, alumina, etc.); silicon-based materials, such as silicon dioxide or silicon oxide; cerium dioxide and cerium dioxide-based materials; zirconium oxide and zirconium oxide-based materials; and others. The example compositions of this specification may contain less than 0.1, 0.05, 0.01, or 0.001% by weight of any such solid (undissolved) abrasive particles (total) based on the total weight of the composition (concentrate or used composition).

[0088] The cleaning composition can be easily prepared by simply adding the appropriate ingredients and mixing to homogeneous conditions (e.g., a solution). Furthermore, the composition can be easily formulated as a single-package formulation or as a multi-part formulation to be mixed during or before use; for example, individual portions of a multi-part formulation can be mixed by the user at the treatment tool (cleaning equipment) or in a storage tank upstream of the treatment tool.

[0089] The compositions described are commercially available for sale in concentrate form, which can be diluted with an appropriate amount of water upon use, i.e., diluted to a "use composition". The composition in concentrate form (the concentrate) includes a non-aqueous component (e.g., alkali, cleaning compound, corrosion inhibitor, and other optional components) present in the concentrate in a certain amount such that when the concentrate is diluted with the required amount of water (e.g., deionized water), the components of the cleaning composition will be present in the diluted use composition in the amount required for a cleaning step, such as a post-CMP cleaning step. The amount of water added to the concentrate to form the use composition can be one or more volumes of water per volume of concentrate, for example, 2 volumes of water per volume of concentrate (e.g., 3, 4, 5, or 10 volumes of water). When the concentrate is diluted with this amount of water, the solid components of the concentrate will be present in the use composition at a reduced concentration based on the number of volumes of water added to dilute the concentrate.

[0090] The cleaning compositions described herein are suitable for microelectronic device processing applications, including methods for cleaning substrate surfaces using techniques such as post-etching residue removal, post-ashing residue removal surface preparation, post-CMP residue removal, etc. Examples of substrates that can be cleaned by such methods include substrates whose surfaces comprise metallic copper, metallic cobalt, or both, for example as metal interconnects (e.g., copper interconnects), or as barrier layer materials (e.g., cobalt) between metal interconnects and dielectric or low-k dielectric materials. Some examples of microelectronic device substrates that have been cleaned with particularly useful or advantageous results include those with exposed structures on their surfaces comprising metallic copper (e.g., copper or alloys thereof), metallic cobalt (e.g., cobalt or alloys thereof), and dielectric or low-k dielectric materials. The corrosion inhibition of the cleaning composition can be reflected in measurements of the metal etching rate, such as the static etching rate, which can be performed using known methods with known equipment.

[0091] The cleaning composition and method preferably effectively remove a large amount of residue from the surface, the amount initially present on the surface before the cleaning step. Simultaneously, the composition and method are effective without causing undue damage to dielectric or low-k dielectric materials also present on the surface, and without causing undue corrosion to metal interconnects or barrier layer materials (e.g., copper, cobalt, or both) also present on the selected substrate surface. Preferably, the cleaning composition effectively removes at least 85% of the residue present on the substrate surface before residue removal by the cleaning step, more preferably at least 90% of the residue, even more preferably at least 95% of the residue, and most preferably at least 99% of the residue initially present before the cleaning step.

[0092] In cleaning steps, such as post-CMP residue cleaning, the cleaning composition can be used with any of a variety of known, conventional, and commercially available cleaning tools, such as UHF ultrasonic and brush cleaning, including (but not limited to) Verteq single-wafer UHF ultrasonic Goldfinger, OnTrak system DDS (double-sided scrubber), SEZ or other single-wafer spray rinsing, Applied Materials Mirra-Mesa™ / Reflexion™ / Reflexion LK™, and UHF ultrasonic batch wet cleaning station systems.

[0093] The conditions and timing of the cleaning steps can be varied as needed and depending on the type of substrate and residue. When using a composition for cleaning CMP residues, etch residues, ashing residues, or contaminants from a microelectronic device substrate, the cleaning composition can be contacted with the substrate surface for about 1 second to about 20 minutes, for example, about 5 seconds to 10 minutes or about 15 seconds to about 5 minutes, at a temperature ranging from about 20°C to about 90°C, preferably from about 20°C to about 50°C. Such contact times and temperatures are illustrative, and any other suitable time and temperature conditions may be applied, where applicable, to at least partially, preferably substantially, clean the initial amount of residue from the surface.

[0094] After the required level of cleaning is achieved on the device substrate surface, the cleaning composition used in the cleaning steps is readily removed from the device surface, as may be desired and effective in the intended end-use application. For example, this can be achieved by using a rinsing solution comprising deionized water. Subsequently, the device may be treated as needed, for example by drying (e.g., using nitrogen or centrifugal dehydration cycles), followed by subsequent cleaning and drying of the device surface.

[0095] In other, more general or specific methods, the microelectronic device substrate may first undergo processing steps including any and more of the following: CMP treatment, plasma etching, wet etching, plasma ashing, etc., followed by a cleaning step including cleaning the substrate surface with the cleaning composition of this specification. At the end of the first processing step, residues (e.g., post-etching residues, post-CMP residues, post-ashing residues, etc.) will remain on the substrate surface. The cleaning step using the cleaning composition as described will effectively remove a large amount of residues from the microelectronic device surface.

[0096] Example

[0097] Some example cleaning compositions may consist of various guanidine compounds, monoethanolamine, and potassium hydroxide (or, alternatively, essentially consist of them). See Table 1:

[0098] Table 1.

[0099]

[0100] Other example cleaning compositions may consist of various pyrazolones, monoethanolamines, and potassium hydroxide (or, alternatively, essentially consist of them). See Table 2:

[0101] Table 2.

[0102]

[0103] Other example cleaning compositions may consist of (or be substantially composed of) 8-hydroxyquinoline, monoethanolamine, various amino acids, and potassium hydroxide. See Table 3:

[0104] Table 3.

[0105]

[0106] Tables 1-3 show the formulations of various cleaning compositions as described herein, as well as equivalent cleaning compositions containing comparable alkalis and other ingredients but without any of the corrosion inhibitors described herein. The effectiveness of each of these compositions is compared with copper etching rate and electrochemical impedance results. See also Figures 1 to 4 .

[0107] Etching rate, or static etching rate, is a measure of the amount of metal removed from a metal surface after it has been exposed to certain materials, such as a cleaning composition. Figure 1 As shown, the cleaning compositions of the present invention, containing corrosion inhibitors as described herein and having specific alkaline materials, exhibit lower etching rates compared to control solutions.

[0108] Corrosion of metallic surface features is a major cause of microelectronic device failure. Metal corrosion on the surface of microelectronic devices can occur during processing, such as during cleaning steps. This means that processing steps should not promote and preferably should reduce, inhibit, or prevent the occurrence of corrosion on the surface features of microelectronic devices. Corrosion inhibition can be measured using electrochemical impedance spectroscopy. Figure 4 As shown in the Nyquist curve, the cleaning compositions of the present invention containing corrosion inhibitors as described herein and specific alkaline materials cause a higher degree of copper passivation compared to cleaning compositions that do not contain any of the corrosion inhibitors of the present invention.

Claims

1. A cleaning composition for effectively cleaning substrates of microelectronic devices, the cleaning composition comprising: water, An alkaline solution is needed to provide a pH of at least 8. Cleaning compounds, and Corrosion inhibitors, wherein the corrosion inhibitors are: 2-methyl-3-butyn-2-ol, 3-methyl-2-pyrazolin-5-one, 3-methyl-1-(4-sulfophenyl)-2-pyrazolin-5-one, or 3-methyl-1-p-tolyl-5-pyrazolinone. The base is selected from: choline hydroxide, tetraethylammonium hydroxide, tetramethylammonium hydroxide, quaternary ammonium compounds and combinations thereof, and The cleaning compound mentioned above is an alkanolamine.

2. The cleaning composition according to claim 1, wherein the cleaning composition comprises a secondary cleaning compound selected from: morpholine, L-cysteine, hydroxyethyl cellulose, polyvinylpyrrolidone, polyamines, glycol ethers, and combinations thereof.

3. The cleaning composition according to claim 1, wherein the cleaning composition comprises a secondary corrosion inhibitor selected from oxalic acid, succinic acid, L-tartaric acid, and combinations thereof.

4. The cleaning composition according to claim 1, wherein the cleaning composition comprises one or more of the following: chelating agent, oxidizing agent, surfactant, oxygen scavenger, solvent, polymer, and buffer.

5. A method for cleaning a substrate of a microelectronic device, the method comprising: Provide a cleaning composition according to any one of claims 1 to 4, Provides substrates for microelectronic devices, and The surface of the microelectronic device substrate is brought into contact with the cleaning composition.

6. The method of claim 5, wherein the surface of the substrate includes residues, and the method effectively removes at least 70% of the residues.

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