Etchant composition for multilayered metal film of copper and molybdenum, method of etching using said composition, and method for prolonging life of said composition
10655231 ยท 2020-05-19
Assignee
Inventors
Cpc classification
International classification
Abstract
Provided is an etchant composition for a multilayered metal film comprising both a layer comprising copper and a layer comprising molybdenum, the etchant composition: being capable of etching en bloc a multilayered metal film comprising a layer constituted of copper or an alloy including copper as the main component and a layer constituted of molybdenum or an alloy including molybdenum as the main component; being effective in preventing the molybdenum layer from being undercut; making it easy to regulate the component concentrations so as to accommodate the cross-sectional shape control and cross-section; and being stable. Also provided are a method of etching using the etchant composition and a method for prolonging the life of the etchant composition. The etchant composition according to the present invention is an etchant composition for use in etching en bloc a multilayered metal film comprising a layer constituted of copper or an alloy including copper as the main component and a layer constituted of molybdenum or an alloy including molybdenum as the main component, and comprises hydrogen peroxide, an organic acid, an amine compound, an azole, and a hydrogen peroxide stabilizer (no inorganic acid is contained therein).
Claims
1. A method for batch etching a metal laminate film comprising a layer formed from copper or an alloy having copper as a main component and a layer formed from molybdenum or an alloy having molybdenum as a main component, the method comprising a step of carrying out etching using an etching solution composition comprising hydrogen peroxide, an organic acid, an amine compound, an azole, a hydrogen peroxide stabilizing agent, and a step of adding to the etching solution composition that has been used in etching an organic acid and at least one selected from the group consisting of a phosphonic acid-based chelating agent, an alcohol-based solvent, a diol-based solvent, a triol-based solvent, a ketone-based solvent, a nitrogen-containing five-membered ring-based solvent, and a sulfoxide-based solvent, and wherein the etching solution does not contain an inorganic acid.
2. The method according to claim 1, wherein it is used in a production process or a packaging process for any one of a liquid crystal display, a color film, a touch panel, an organic EL display, an electronic paper, a MEMS, and an IC.
Description
BRIEF DESCRIPTION OF DRAWINGS
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MODES FOR CARRYING OUT THE INVENTION
(6) Embodiments of the present invention are described in detail below.
(7) A laminate film that is to be etched with the etching solution composition of the present invention is a laminate film that has a Mo or Mo alloy layer formed on a glass or silicon substrate, for example, a laminate film in which a Mo or Mo alloy layer is formed as a barrier metal on a glass substrate by a sputtering method and a Cu or Cu film is further formed thereon, examples of the composition of the laminate film including Cu/Mo, Cu/MoTi, Cu/MoFe, and Cu/MoZr.
(8) The Mo alloy contains Mo as a main component and is an alloy containing Mo and any another metal, for example, containing at least 80 wt % of Mo, preferably at least 90 wt % of Mo, and more preferably at least 95 wt % of Mo.
(9) Furthermore, in the present specification, Cu/Mo denotes a two-layer film in which Cu and Mo are layered in that order from the surface layer. A TFT (Thin Film Transistor) controls light by means of a flat panel display liquid crystal. The TFT includes a gate electrode and a source/drain electrode, the gate electrode being positioned in the lowest layer of the TFT, and the source/drain electrode being positioned in an upper layer. The gate electrode often has a Cu/Mo laminate film set so as to be relatively thick from the viewpoint of electrical properties, whereas the source/drain electrode is sometimes set rather thin. For example, the copper of the gate electrode is 6000 and the copper of the source/drain electrode is 3000 . It is therefore desirable to adjust the composition so as to be able to cope with either of the film thicknesses.
(10) The film thickness of the laminate film is not particularly limited, but is preferably 1000 to 8000 , and more preferably 3000 to 6000 . The film thickness of Cu is not particularly limited, but is preferably 2000 to 7000 , and more preferably 3000 to 6000 . The film thickness of Mo or the Mo alloy is not particularly limited, but is preferably 50 to 500 , and more preferably 100 to 300 .
(11) The etching solution composition of the present invention contains hydrogen peroxide, an organic acid, an amine compound, an azole, and a hydrogen peroxide stabilizing agent, and does not contain an inorganic acid.
(12) The hydrogen peroxide used as an oxidizing agent in the etching solution composition of the present invention has the function of oxidizing copper wiring and has the function of oxidizing and dissolving molybdenum, the content thereof in the etching solution being preferably 5 to 20 mass %, and more preferably 5 to 10 mass %. It is preferable for the hydrogen peroxide content to be in this range since management of hydrogen peroxide is easy, an appropriate etching speed can be ensured, and control of the amount of etching becomes easy.
(13) The organic acid used in the etching solution composition of the present invention contributes to etching of copper and molybdenum and removal of a molybdenum-derived residue, the content thereof in the etching solution composition being preferably 0.5 to 20 mass %, and more preferably 5 to 10 mass %. When the content of the organic acid is in this range, etching of copper and molybdenum and removal of a molybdenum-derived residue is carried out fully, and a good wiring cross-sectional shape can be obtained after etching. Furthermore, it also functions as a masking agent for copper ions contained after etching, thus enabling decomposition of hydrogen peroxide by copper to be suppressed.
(14) Examples of the organic acid include an aliphatic carboxylic acid having 1 to 18 carbons, an aromatic carboxylic acid having 6 to 10 carbons, and an amino acid having 1 to 10 carbons.
(15) Examples of the aliphatic carboxylic acid having 1 to 18 carbons include formic acid, acetic acid, propionic acid, lactic acid, glycolic acid, diglycolic acid, pyruvic acid, malonic acid, butyric acid, hydroxybutyric acid, tartaric acid, succinic acid, malic acid, maleic acid, fumaric acid, valeric acid, glutaric acid, itaconic acid, adipic acid, caproic acid, adipic acid, citric acid, propanetricarboxylic acid, trans-aconitic acid, enanthic acid, caprylic acid, lauric acid, myristic acid, palmitic acid, stearic acid, oleic acid, linoleic acid, and linolenic acid.
(16) Examples of the aromatic carboxylic acid having 6 to 10 carbons include benzoic acid, salicylic acid, mandelic acid, phthalic acid, isophthalic acid, and terephthalic acid.
(17) Examples of the amino acid having 1 to 10 carbons include carbamic acid, alanine, glycine, cystine, asparagine, aspartic acid, sarcosine, serine, glutamine, glutamic acid, 4-aminobutyric acid, iminodibutyric acid, arginine, leucine, isoleucine, and nitrilotriacetic acid.
(18) Among the above organic acids, preferred examples include alanine, glutamic acid, glycine, glycolic acid, succinic acid, cystine, aspartic acid, malic acid, malonic acid, lactic acid, and acetic acid, and more preferred examples include malonic acid and succinic acid.
(19) The amine compound used in the etching solution composition of the present invention contributes to a good wiring cross-sectional shape after etching and is a compound having 2 to 10 carbons and a total number of amino groups and hydroxy groups of two or more.
(20) Examples of such an amine compound include polyamines such as ethylenediamine, trimethylenediamine, tetramethylenediamine, 1,2-propanediamine, 1,3-propanediamine, N,N-dimethyl-1,3-propanediamine, N,N-diethyl-1,3-propanediamine, 1,3-diaminobutane, 2,3-diaminobutane, pentamethylenediamine, 2,4-diaminopentane, hexamethylenediamine, heptamethylenediamine, octamethylenediamine, nonamethylenediamine, N-methylethylenediamine, N,N-dimethylethylenediamine, trimethylethylenediamine, N-ethylethylenediamine, N,N-diethylethylenediamine, triethylethylenediamine, 1,2,3-triaminopropane, hydrazine, tris(2-aminoethyl)amine, tetra(aminomethyl)methane, diethylenetriamine, triethylenetetramine, tetraethylpentamine, heptaethyleneoctamine, nonaethylenedecamine, and diazabicycloundecene; alkanolamines such as ethanolamine, N-methylethanolamine, N-methyldiethanolamine, N-ethylethanolamine, N-aminoethylethanolamine, N-propylethanolamine, N-butylethanolamine, diethanolamine, triethanolamine, 2-aminoethanol, 1-amino-2-propanol, N-methylisopropanolamine, N-ethylisopropanolamine, N-propylisopropanolamine, 2-aminopropan-1-ol, N-methyl-2-aminopropan-1-ol, N-ethyl-2-aminopropan-1-ol, 1-aminopropan-3-ol, N-methyl-1-aminopropan-3-ol, N-ethyl-1-aminopropan-3-ol, 1-aminobutan-2-ol, N-methyl-1-aminobutan-2-ol, N-ethyl-1-aminobutan-2-ol, 2-aminobutan-1-ol, N-methyl-2-aminobutan-1-ol, N-ethyl-2-aminobutan-1-ol, 3-aminobutan-1-ol, N-methyl-3-aminobutan-1-ol, N-ethyl-3-aminobutan-1-ol, 1-aminobutan-4-ol, N-methyl-1-aminobutan-4-ol, N-ethyl-1-aminobutan-4-ol, 1-amino-2-methylpropan-2-ol, 2-amino-2-methylpropan-1-ol, 1-aminopentan-4-ol, 2-amino-4-methylpentan-1-ol, 2-aminohexan-1-ol, 3-aminoheptan-4-ol, 1-aminooctan-2-ol, 5-aminooctan-4-ol, 2-amino-2-methyl-1-propanol, 1-aminopropane-2,3-diol, 2-aminopropane-1,3-diol, tris(oxymethyl)aminomethane, 1,2-diaminopropan-3-ol, 1,3-diaminopropan-2-ol, 2-(2-aminoethoxy)ethanol, 2-(2-aminoethylamino)ethanol, and diglycolamine; and quaternary ammonium salts such as tetramethylammonium hydroxide, and they can be used on their own or in a combination of a plurality thereof. Among the above amine compounds, preferred examples include 2-amino-2-methyl-1-propanol, 1-amino-2-propanol, 2-aminoethanol, and tetramethylammonium hydroxide, and more preferred examples include 2-amino-2-methyl-1-propanol and 1-amino-2-propanol.
(21) The content of the amine compound in the etching solution composition of the present invention is preferably 5 to 20 mass %, and more preferably 5 to 10 mass %. When the content of the amine compound is in this range, a good wiring cross-sectional shape can be obtained after etching.
(22) Examples of the azole used in the etching solution composition of the present invention include triazoles such as 1,2,4-1H-triazole, 1H-benzotriazole, 5-methyl-1H-benzotriazole, and 3-amino-1H-triazole, for example 3-amino-1H-1,2,4-triazole; tetrazoles such as 1H-tetrazole, 5-methyl-1H-tetrazole, 5-phenyl-1H-tetrazole, and 5-amino-1H-tetrazole; imidazoles such as 1H-imidazole and 1H-benzoimidazole; and triazoles such as 1,3-thiazole and 4-methylthiazole. Among them, a triazole and a tetrazole are preferable, and 1,2,4-1H-triazole, 3-amino-1H-1,2,4-triazole, and 5-amino-1H-tetrazole are particularly preferable.
(23) The content of the azole in the etching solution composition is preferably 0.005 to 0.2 mass %, and more preferably 0.01 to 0.05 mass %. When the content of the azole is in this range, a good wiring cross-sectional shape can be obtained after etching while suppressing any increase in side etching after etching.
(24) The etching solution composition of the present invention contains a hydrogen peroxide stabilizer. Any hydrogen peroxide stabilizer may be used without limitation as long as it is one usually used as a hydrogen peroxide stabilizer, but preferred examples include urea-based hydrogen peroxide stabilizers such as phenylurea, allylurea, 1,3-dimethylurea, and thiourea and, furthermore, phenylacetamide, phenylethylene glycol, tetrasodium pyrophosphate, sodium stannate, barbituric acid, uric acid, acetanilide, oxyquinoline, salicylic acid, phenacetin, sodium silicate, an alkyldiaminetetramethylenephosphonic acid or a salt thereof, and 1,10-phenanthroline, and phenylurea is particularly preferable.
(25) The content of the hydrogen peroxide stabilizer in the etching solution composition of the present invention is preferably 0.05 to 0.5 mass % from the viewpoint of fully obtaining the effect from the addition thereof, and more preferably 0.1 to 0.3 mass %.
(26) The etching solution composition of the present invention does not contain an inorganic acid, and this makes it possible to avoid the problems with handling during production that occur when a strongly acidic inorganic acid such as sulfuric acid or nitric acid is used and the problems with other inorganic acids such as phosphoric acid that are difficult to put into practical use.
(27) Since the etching solution composition of the present invention is used for etching of a substrate for which undercutting of a molybdenum layer easily occurs, the organic acid is used as an acid component, but if the etching solution composition is used continuously for a long period of time, problems occur in terms of the etching performance deteriorating accompanying an increase in the amount of copper dissolved or large amounts of bubbles being produced, the temperature increasing, and precipitates being produced due to the activity of the solution increasing. However, since the etching composition of the present invention contains at least one selected from the group consisting of a phosphonic acid-based chelating agent, an alcohol-based solvent, a diol-based solvent, a triol-based solvent, a ketone-based solvent, a nitrogen-containing five-membered ring-based solvent, and a sulfoxide-based solvent, it becomes possible to increase the amount of copper dissolved, extend the life span of the solution and, furthermore, suppress undercutting of a molybdenum layer.
(28) Although hydrogen peroxide has the problem that it easily decomposes when metal ions are present, since a phosphonic acid-based chelating agent that is additionally contained in the etching composition of the present invention easily forms a chelate with various types of metals, and it exhibits the effects even when there is contamination with another metal, particularly when a low purity reagent is used, it becomes possible to suppress decomposition of hydrogen peroxide. Furthermore, it is surmised that the diol-based solvent and triol-based solvent additionally contained in the etching solution composition of the present invention suppress undercutting of a molybdenum layer by imparting viscosity to the etching solution composition. Moreover, the ketone-based solvent, nitrogen-containing five-membered ring-based solvent, and sulfoxide-based solvent additionally contained in the etching solution composition of the present invention suppress undercutting of a molybdenum layer due to their action in protecting the surface of molybdenum.
(29) Examples of the phosphonic acid-based chelating agent used in the etching solution composition of the present invention include methanediphosphonic acid, 1-hydroxyethane-1,1-diphosphonic acid, 1-hydroxypropane-1,1-diphosphonic acid, aminotri(methylenephosphonic acid), ethylaminodi(methylenephosphonic acid), ethylenediaminedi(methylenephosphonic acid), ethylenediaminetetra(methylenephosphonic acid), diethylenetriaminepenta(methylenephosphonic acid), 1,2-propanediaminetetra(methylenephosphonic acid), and an ammonium salt, alkali metal salt, and organic amine salt thereof. Examples thereof further include an oxidized form of these phosphonic acid-based chelating agents that have a nitrogen atom in the molecule that has been oxidized to the N-oxide form.
(30) Among the above phosphonic acid-based chelating compounds, 1-hydroxyethane-1,1-diphosphonic acid, 1-hydroxypropane-1,1-diphosphonic acid, and aminotri(methylenephosphonic acid) are preferable.
(31) The content of the phosphonic acid-based chelating agent in the etching solution composition of the present invention is preferably 0.1 to 20 mass %, and more preferably 1 to 6 mass %. When in this range, the effect in suppressing Mo undercutting is easily obtained, and it is effective from the viewpoint of cost.
(32) Examples of the alcohol-based solvent used in the etching solution composition of the present invention include monohydric alcohols such as methanol, ethanol, propanol, 2-propanol, and 1-butanol and dihydric alcohols such as ethylene glycol, propylene glycol, and butylene glycol. Examples further include a water-soluble polymer compound selected from polyethylene glycol, polypropylene glycol, and polyvinyl alcohol. One or more thereof may be used. Among them, propanol, 2-propanol, and 1-butanol are preferable, and propanol and 2-propanol are more preferable.
(33) The content of the alcohol-based solvent in the etching solution composition of the present invention is preferably 0.1 to 50 mass %, and more preferably 2 to 10 mass %. When the content of the alcohol-based solvent is in this range, a good wiring cross-sectional shape can be obtained after etching while suppressing Mo undercutting after etching.
(34) Examples of the diol-based solvent used in the etching solution composition of the present invention include dipropylene glycol, 1,3-propanediol, 2,3-butanediol, 1,4-butanediol, and 1,5-pentanediol. Among them, dipropylene glycol, 1,3-propanediol, 2,3-butanediol, and 1,4-butanediol are preferable, and dipropylene glycol is more preferable.
(35) The content of the diol-based solvent in the etching solution composition of the present invention is preferably 0.1 to 50 mass %, and more preferably 2 to 10 mass %. When the content of the diol-based solvent is in this range, a good wiring cross-sectional shape can be obtained after etching while suppressing Mo undercutting after etching.
(36) Examples of the triol-based solvent used in the etching solution composition of the present invention include glycerol.
(37) The content of the triol-based solvent in the etching solution composition of the present invention is preferably 0.1 to 50 mass %, and more preferably 2 to 10 mass %. When the content of the triol-based solvent is in this range, a good wiring cross-sectional shape can be obtained after etching while suppressing Mo undercutting after etching.
(38) Examples of the ketone-based solvent used in the etching solution composition of the present invention include acetone, ethyl methyl ketone, diethyl ketone, methyl propyl ketone, ethyl propyl ketone, and dipropyl ketone. Among them, acetone is preferable.
(39) The content of the ketone-based solvent in the etching solution composition of the present invention is preferably 0.1 to 50 mass %, and more preferably 2 to 10 mass %. When the content of the ketone-based solvent is in this range, a good wiring cross-sectional shape can be obtained after etching while suppressing Mo undercutting after etching.
(40) Examples of the nitrogen-containing five-membered ring-based solvent used in the etching solution composition of the present invention include N-methyl-2-pyrrolidinone and 2-pyrrolidinone. Among them, N-methyl-2-pyrrolidinone is preferable.
(41) The content of the nitrogen-containing five-membered ring-based solvent in the etching solution composition is preferably 0.1 to 50 mass %, and more preferably 2 to 10 mass %. When the content of the nitrogen-containing five-membered ring-based solvent is in this range, a good wiring cross-sectional shape can be obtained after etching while suppressing Mo undercutting after etching.
(42) Examples of the sulfoxide-based solvent used in the etching solution composition of the present invention include dimethyl sulfoxide.
(43) The content of the sulfoxide-based solvent in the etching solution composition of the present invention is preferably 0.1 to 50 mass %, and more preferably 2 to 10 mass %. When the content of the sulfoxide-based solvent is in this range, a good wiring cross-sectional shape can be obtained after etching while suppressing Mo undercutting after etching.
(44) The phosphonic acid-based chelating agent, the alcohol-based solvent, the diol-based solvent, the triol-based solvent, the ketone-based solvent, the nitrogen-containing five-membered ring-based solvent, and/or the sulfoxide-based solvent may be added when preparing the etching solution composition or may be added to the etching composition while it is being used for etching.
(45) The etching solution composition of the present invention may contain, in addition to the above components, water and various types of additives that are usually used in an etching solution composition in a range that does not impair the effects of the etching solution composition. The water is preferably one from which metal ions, organic impurities, and particles have been removed by distillation, ion-exchange treatment, filter treatment, various types of adsorption treatment, etc., and pure water and ultrapure water are particularly preferable.
(46) The etching solution composition of the present invention preferably has a pH of 3 to 6. When its pH is less than 3 or greater than 6, the hydrogen peroxide easily decomposes.
(47) The etching method of the present invention comprises etching a metal laminate film that contains a layer formed from copper or an alloy having copper as a main component and a layer formed from molybdenum or an alloy having molybdenum as a main component using an etching solution composition that is used for etching a metal laminate film that contains a layer formed from copper or an alloy having copper as a main component and a layer formed from molybdenum or an alloy having molybdenum as a main component, the etching solution composition containing hydrogen peroxide, an organic acid, an amine compound, an azole, and a hydrogen peroxide stabilizing agent and not containing an inorganic acid, the method comprising a step of bringing an etching target and the etching solution composition of the present invention into contact. Furthermore, it has been found that in accordance with the etching method of the present invention, a metal laminate film that contains a layer formed from copper or an alloy having copper as a main component and a layer formed from molybdenum or an alloy having molybdenum as a main component can be etched as a whole, and it becomes possible to suppress undercutting of the molybdenum layer, thus enabling control of the cross-sectional shape to be easily carried out.
(48) In the etching method of the present invention, the etching solution composition employs as an etching target one in which, as shown in for example
(49) The copper wiring is not particularly limited as long as it is formed from copper or a material having copper as a main component, and examples of the molybdenum-based material forming the barrier film include molybdenum metal and a molybdenum-based alloy.
(50) The method for bringing the etching target into contact with the etching solution composition is not particularly limited, and a wet etching method can be employed such as for example a method in which the target is brought into contact with the etching solution composition in a manner such as dropwise addition (single wafer spin process) or spraying and a method in which the target is immersed in the etching solution composition. In the present invention, the method in which the target is brought into contact with the etching solution composition by dropwise addition thereof (single wafer spin process) and the method in which the target is immersed in the etching solution composition are preferably employed.
(51) The temperature at which the etching solution composition is used is preferably 15 C. to 60 C., and particularly preferably 30 C. to 50 C. When the temperature of the etching solution composition is 20 C. or greater, the etching speed does not become too low, and the production efficiency does not greatly deteriorate. On the other hand, if the temperature is less than the boiling point, it is possible to suppress any change in the solution formula, thus maintaining constant etching conditions. Although the etching speed is increased by raising the temperature of the etching solution composition, an optimum treatment temperature may be determined as appropriate while taking into consideration suppression of change in the formula of the etching solution composition.
(52) The etching solution composition usually uses a replenisher solution for the purpose of increasing the amount of copper dissolved and prolonging the use of the composition in order to cut the cost. The replenisher solution is used for replenishing the organic acid that is consumed by etching, and in the present invention the life span of the solution can be greatly extended by adding to the etching solution composition as the replenisher solution the organic acid used in the etching solution composition of the present invention and at least one selected from the group consisting of a phosphonic acid-based chelating agent, an alcohol-based solvent, a diol-based solvent, a triol-based solvent, a ketone-based solvent, a nitrogen-containing five-membered ring-based solvent, and a sulfoxide-based solvent rather than a case in which only the organic acid is used as the replenisher solution.
(53) The amount of organic acid added as the replenisher solution is preferably 0.1 to 10 mass % relative to 100 mass % of the etching solution composition, and more preferably 0.1 to 5 mass %. The amount of phosphonic acid-based chelating agent, alcohol-based solvent, diol-based solvent, triol-based solvent, ketone-based solvent, nitrogen-containing five-membered ring-based solvent, and/or sulfoxide-based solvent added as the replenisher solution is preferably 0.1 to 20 mass % relative to 100 mass % of the etching solution composition, and more preferably 2 to 10 mass %.
EXAMPLES
(54) The present invention is further specifically explained below by way of Examples and Comparative Examples, but the present invention should not be construed as being limited to these Examples and may be modified in a variety of ways as long as the modifications do not depart from the technical scope of the present invention.
(55) [Preparation of Copper/Molybdenum Substrate]
(56) A copper/molybdenum-based multi-layer thin film was prepared by forming a barrier film of molybdenum (Mo) using glass as a substrate and sputtering molybdenum, then forming copper wiring by sputtering copper, then coating it with a resist, and forming a pattern by exposure transfer through a pattern mask and developing.
(57) The Cu film thickness and the Mo film thickness of the substrates used in each of the Examples and Comparative Examples are shown in Tables 1 to 5 and 12 to 14.
Examples 1 and 2
Etching Test
(58) The etching solution compositions shown in Table 1 were each placed in a beaker, and the temperature was stabilized in a thermostatted chamber kept at 35 C. While stirring the etching solution composition with a stirrer, a 11 cm copper/molybdenum substrate was immersed therein, and the etching time was measured. The etching time measured when copper and molybdenum disappeared was defined as the just-etching time, and a time that was about twice the just-etching time was defined as the actual etching time (over-etching time). In Examples 1 and 2, etching was carried out by defining a time that was twice the just-etching time given in Table 1 as the over-etching time; after a treatment involving washing with water and drying, the cross-sectional shape was examined by SEM, and the performance was evaluated in terms of the amount of side etching, the taper angle, Mo residue, Mo undercutting, etc.
(59) Each of the terms is explained using
(60) The results are shown in Table 1. With regard to the designations A to C used for the Mo residue in the table, A is very good, B is good, and C is poor. With regard to the designations A to C in
(61) TABLE-US-00001 TABLE 1 Example 1 Example 2 (A) Hydrogen peroxide (wt %) 10 10 (B) Malonic acid (wt %) 5 5 Succinic acid (wt %) 5 9 (C) MIPA (wt %) 10 10.5 (D) ATZ (wt %) 0.01 0.01 (E) Phenylurea (wt %) 0.5 0.5 (F) HEDP (wt %) Water Remainder Remainder Copper powder (ppm) pH 4.6 4.4 Cu film thickness/Mo film thickness (/) 5500/200 5500/200 JET (sec) 62 71 S/E (m) 1.48 1.50 T/A () 34 32 Mo residue A A Mo undercutting A A MIPA: 1-amino-2-propanol ATZ: 5-amino-1H-tetrazole HEDP: 1-hydroxyethane-1,1-diphosphonic acid JET: just-etching time S/E: side etching T/A: taper angle
(62) It can be seen from Table 1 that the etching solution composition of the present invention, which does not contain an inorganic acid, suppresses Mo undercutting without containing an inorganic acid.
Examples 3 to 8
Etching Test
(63) Etching was carried out in the same way as for Example 1 except that the etching solution compositions shown in Table 2 and substrates having the Mo film thicknesses shown in Table 2 were used, the over-etching time being twice the just-etching time.
(64) The results are shown in Table 2 and
(65) TABLE-US-00002 TABLE 2 Example 3 Example 4 Example 5 Example 6 Example 7 Example 8 (A) Hydrogen peroxide (wt %) 10 10 10 10 10 10 (B) Malonic acid (wt %) 2 2 2 2 2 2 Succinic acid (wt %) 8 8 8 8 8 8 (C) MIPA (wt %) 8 8 8 8 8 8 (D) ATZ (wt %) 0.01 0.01 0.01 0.01 0.01 0.01 (E) Phenylurea (wt %) 0.5 0.5 0.5 0.5 0.5 0.5 (F) HEDP (wt %) 3.0 3.5 4.0 3.0 3.5 4.0 Water Remainder Remainder Remainder Remainder Remainder Remainder Copper powder (ppm) pH 4.2 4.2 4.1 4.2 4.2 4.1 Cu film thickness/Mo film 5000/140 5000/140 5000/140 5000/280 5000/280 5000/280 thickness (/) JET (sec) 70 70 69 75 75 75 S/E (m) 1.40 1.48 1.60 1.67 1.66 1.78 T/A () 29 28 31 30 29 33 Mo residue A A A A A A Mo undercutting B A A B A A
(66) It is clear that Mo undercutting is suppressed in response to an increase in the amount of 1-hydroxyethane-1,1-diphosphonic acid (HEDP) added. Furthermore, it is clear that Mo undercutting can be suppressed not only for a substrate having a Mo film thickness of 140 but also for a substrate having a film thickness of 280 .
Examples 9 to 20
Etching Test
(67) Etching was carried out in the same way as for Example 1 except that the amount of copper powder shown in Tables 3 and 4 was dissolved in an etching solution composition having the pH shown in Tables 3 and 4, the over-etching time being 124 seconds for Examples 9 and 11 to 13 and 142 seconds for Examples 10 and 14 to 20.
(68) The results are shown in Tables 3 and 4.
(69) TABLE-US-00003 TABLE 3 Example 9 Example 10 Example 11 Example 12 Example 13 (A) Hydrogen peroxide (wt %) 10 10 10 10 10 (B) Malonic acid (wt %) 5 5 7 8 9 Succinic acid (wt %) 5 9 5 5 5 (C) MIPA (wt %) 10 10.5 10 10 10 (D) ATZ (wt %) 0.01 0.01 0.01 0.01 0.01 (E) Phenylurea (wt %) 0.5 0.5 0.5 0.5 0.5 (F) HEDP (wt %) Water Remainder Remainder Remainder Remainder Remainder Copper powder (ppm) 8000 8000 8000 8000 8000 pH 4.6 4.5 4.1 3.9 3.7 Cu film thickness/Mo film 5500/200 5500/200 5500/200 5500/200 5500/200 thickness (/) JET (sec) 80 86 60 60 45 S/E (m) 0.87 1.04 1.38 1.65 1.87 T/A () 42 34 47 43 44 Mo residue A A A A A Mo undercutting C C C C C
(70) TABLE-US-00004 TABLE 4 Example Example Example Example Example Example Example 14 15 16 17 18 19 20 (A) Hydrogen peroxide (wt %) 10 10 10 10 10 10 10 (B) Malonic acid (wt %) 5 5 5 5 5 5 5 Succinic acid (wt %) 9 9 9 9 9 9 9 (C) MIPA (wt %) 10.5 10.5 10.5 10.5 10.5 10.5 10.5 (D) ATZ (wt %) 0.01 0.01 0.01 0.01 0.01 0.01 0.01 (E) Phenylurea (wt %) 0.5 0.5 0.5 0.5 0.5 0.5 0.5 (F) HEDP (wt %) 1.0 1.5 2.0 2.5 3.6 4.3 5.8 Water Remainder Remainder Remainder Remainder Remainder Remainder Remainder Copper powder (ppm) 8000 8000 8000 8000 8000 8000 8000 pH 4.4 4.3 4.3 4.3 4.1 4.0 3.8 Cu film thickness/Mo film 5500/200 5500/200 5500/200 5500/200 5500/200 5500/200 5500/200 thickness (/) JET (sec) 80 80 80 75 70 65 51 S/E (m) 1.17 1.01 1.12 1.00 1.33 1.27 1.04 T/A () 34 35 36 36 40 44 49 Mo residue A A A A A A A Mo undercutting B B A A A A A
(71) It is clear that the etching solution composition containing hydrogen peroxide, malonic acid, succinic acid, 1-amino-2-propanol (MIPA), 5-amino-1H-tetrazole (ATZ), and phenylurea exhibited the same Mo residue as for Examples 1 and 2 regardless of pH in a state in which copper was dissolved as in Examples 9 to 13, but more Mo undercutting occurred than in Examples 1 and 2.
(72) Furthermore, the etching solution composition containing a larger amount of HEDP does not produce Mo undercutting even in a state in which copper is dissolved as in Examples 14 to 20. In particular, since HEDP is acidic, its addition decreases the pH, and when the pH becomes too low, Mo undercutting sometimes occurs, but it is clear that Mo undercutting does not occur regardless of the pH decreasing in response to an increase in the amount of HEDP. It is clear from this result that the life span of the solution can be extended by adding HEDP as a replenisher solution to an etching solution composition that has been used for treating a large amount of substrate.
Examples 21 to 28
Copper Solubility Test
(73) The amount of copper powder shown in Table 5 was dissolved in the etching solution composition shown in Table 5, and the copper solubility in the etching composition was tested. In the test, the etching solution composition shown in Table 5 was placed in a beaker, the copper powder was added thereto while stirring with a stirrer, and the state of the solution was examined.
(74) The results are shown in Table 5.
(75) TABLE-US-00005 TABLE 5 Example Example Example Example Example Example Example Example 21 22 23 24 25 26 27 28 (A) Hydrogen peroxide (wt %) 8 8 8 8 8 8 8 8 (B) Malonic acid (wt %) 1 1 1 1 1 1 1 1 Succinic acid (wt %) 9 9 9 9 9 9 9 9 (C) MIPA (wt %) 8 8 8 8 8 8 8 8 (D) ATZ (wt %) 0.01 0.01 0.01 0.01 0.01 0.01 0.01 0.01 (E) Phenylurea (wt %) 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 (F) HEDP (wt %) 2 2 2 2 Water Remainder Remainder Remainder Remainder Remainder Remainder Remainder Remainder Copper powder (ppm) 1000 2000 3000 4000 6000 8000 10000 12000 Copper solubility A A C C A A A C Solution state Large Precipitate Precipitate amount produced produced of bubbles produced
(76) The etching solution composition containing hydrogen peroxide, malonic acid, succinic acid, MIPA, ATZ, and phenylurea exhibited the same solubility for copper as in Examples 1 and 2 in a state in which copper was dissolved at 1000 ppm or 2000 ppm as in Examples 21 and 22; on the other hand, in a state in which copper was dissolved at 3000 ppm or 4000 ppm as in Examples 23 and 24, the solubility for copper was insufficient, the occurrence of bubbles or a precipitate was observed, and it is therefore clear that the etching solution composition of the present invention can withstand treatment of a predetermined amount of substrate.
(77) Furthermore, the etching solution compositions further containing HEDP exhibited the same solubility for copper as in Examples 1 and 2 even in a state in which copper was dissolved at 6000 ppm, 8000 ppm, or 10000 ppm as in Examples 25 to 27, whereas in a state in which copper was dissolved at 12000 ppm as in Example 28, the solubility for copper was insufficient, the occurrence of a precipitate was observed, and it is therefore clear that the etching solution composition of the present invention can further withstand treatment of a larger amount of substrate due to it containing HEDP. That is, it is clear from this result that the life span of the solution can be extended by adding HEDP as a replenisher solution to an etching solution composition that has been used for treating a large amount of substrate or when preparing the etching solution composition.
Examples 29 to 58 and Comparative Examples 1 to 20
Replenisher Solution Test
Examples 29 to 58
(78) The etching solution compositions shown in Table 6 were placed in beakers and the temperature was stabilized in a thermostatted chamber kept at 35 C. Copper powder was added at 10000 ppm to the beaker with the etching solution composition and completely dissolved therein, and the vol % given in Tables 7 to 10 relative to 100 vol % of the etching solution composition of a 40 wt % aqueous solution of malonic acid (remainder was water) (replenisher solution A), an alcohol-based solvent (isopropyl alcohol (IPA)), a diol-based solvent (dipropylene glycol (DPG)), a triol-based solvent (glycerol), a ketone-based solvent (acetone), a nitrogen-containing five-membered ring-based solvent (N-methyl-2-pyrrolidinone (NMP)), or a sulfoxide-based solvent (dimethyl sulfoxide (DMSO)) 100 wt % (replenisher solution B) was added. While stirring the etching solution composition with a stirrer, a 11 cm copper/molybdenum substrate (Cu film thickness/Mo film thickness=5500/300) was immersed therein, and the etching time was measured. Etching was carried out with an over-etching time of 144 seconds, which was twice the just-etching time (77 seconds) of the etching solution composition shown in Table 6 to which the copper powder and the replenisher solution were not added; after a treatment involving washing with water and drying, the cross-sectional shape was examined by SEM, and the performance was evaluated from the amount of side etching, the taper angle, Mo residue, Mo undercutting, etc.
(79) The results are shown in Tables 7 to 9.
Comparative Examples 1 to 20
(80) Etching solution compositions were prepared in the same way as above except that the amount of copper powder was set to that shown in Tables 10 and 11 and replenisher solutions A and B were used, and etching was carried out. The results are shown in Tables 10 and 11.
(81) TABLE-US-00006 TABLE 6 (A) Hydrogen peroxide (wt %) 10 (B) Malonic acid (wt %) 5 Succinic acid (wt %) 5 (C) MIPA (wt %) 10 (D) ATZ (wt %) 0.02 (E) Phenylurea (wt %) 0.3 Water Remainder
(82) TABLE-US-00007 TABLE 7 Example Example Example Example Example Example Example Example Example Example 29 30 31 32 33 34 35 36 37 38 Copper powder (ppm) 10000 10000 10000 10000 10000 10000 10000 10000 10000 10000 Replenisher Amt. added 4 4 4 4 4 4 4 4 4 4 solution A (vol %) Replenisher Type DPG DPG DPG DPG DPG IPA IPA IPA IPA IPA solution B Amt. added 2 4 6 8 10 2 4 6 8 10 (vol %) JET (sec) 80 80 80 80 80 80 80 80 80 80 S/E (m) 1.41 1.37 1.31 1.29 1.19 1.31 1.27 1.18 1.19 1.26 T/A () 50 50 46 48 47 52 52 50 48 43 Mo residue A A A A A A A A A A Mo undercutting B A A A A B B A A A pH 4.3 4.3 4.3 4.3 4.3 4.3 4.3 4.4 4.4 4.4 DPG: dipropylene glycol IPA: isopropyl alcohol
(83) TABLE-US-00008 TABLE 8 Example Example Example Example Example Example Example Example Example Example 39 40 41 42 43 44 45 46 47 48 Copper powder (ppm) 10000 10000 10000 10000 10000 10000 10000 10000 10000 10000 Replenisher Amt. added 4 4 4 4 4 4 4 4 4 4 solution A (vol %) Replenisher Type Glycerol Glycerol Glycerol Glycerol Glycerol Acetone Acetone Acetone Acetone Acetone solution B Amt. added 2 4 6 8 10 2 4 6 8 10 (vol %) JET (sec) 80 80 80 80 80 80 80 80 80 80 S/E (m) 1.41 1.38 1.28 1.24 1.22 1.44 1.38 1.27 0.97 0.92 T/A () 52 52 53 52 54 56 51 52 48 27 Mo residue A A A A A A A A A A Mo undercutting B A A A A B B A A A pH 4.2 4.2 4.2 4.2 4.2 4.2 4.3 4.3 4.4 4.4
(84) TABLE-US-00009 TABLE 9 Example Example Example Example Example Example Example Example Example Example 49 50 51 52 53 54 55 56 57 58 Copper powder (ppm) 10000 10000 10000 10000 10000 10000 10000 10000 10000 10000 Replenisher Amt. added 4 4 4 4 4 4 4 4 4 4 solution A (vol %) Replenisher Type NMP NMP NMP NMP NMP DMSO DMSO DMSO DMSO DMSO solution B Amt. added 2 4 6 8 10 2 4 6 8 10 (vol %) JET (sec) 80 80 80 80 80 80 80 80 80 80 S/E (m) 1.38 1.28 1.26 1.25 1.21 1.36 1.45 1.31 1.22 1.16 T/A () 53 52 54 57 51 52 53 56 51 52 Mo residue A A A A A A A A A A Mo undercutting B B B A A B B B A A pH 4.3 4.3 4.4 4.4 4.4 4.3 4.3 4.4 4.4 4.4 NMP: N-methyl-2-pyrrolidinone DMSO: dimethyl sulfoxide
(85) TABLE-US-00010 TABLE 10 Comp. Comp. Comp. Comp. Comp. Comp. Comp. Comp. Comp. Comp. Ex. 1 Ex. 2 Ex. 3 Ex. 4 Ex. 5 Ex. 6 Ex. 7 Ex. 8 Ex. 9 Ex. 10 Copper powder (ppm) 10000 10000 10000 10000 10000 10000 10000 10000 10000 Replenisher Amt. added 2 3 4 5 6 7 8 9 solution A (vol %) Replenisher Type solution B Amt. added (vol %) JET (sec) 77 93 95 90 85 83 80 76 75 75 S/E (m) 1.08 1.07 1.06 1.03 1.15 1.20 1.25 1.30 1.32 1.34 T/A () 40 42 43 42 50 51 52 54 53 58 Mo residue A A A A A A A A A A Mo undercutting B C C C C A B B B B pH 4.4 4.5 4.5 4.5 4.4 4.4 4.3 4.3 4.2 4.2
(86) TABLE-US-00011 TABLE 11 Comp. Comp. Comp. Comp. Comp. Comp. Comp. Comp. Comp. Comp. Ex. 11 Ex. 12 Ex. 13 Ex. 14 Ex. 15 Ex. 16 Ex. 17 Ex. 18 Ex. 19 Ex. 20 Copper powder (ppm) 10000 10000 10000 10000 10000 10000 10000 10000 10000 10000 Replenisher Amt. 4 4 4 4 4 4 4 4 4 4 solution A added (vol %) Replenisher Type BDG BDG Lactic Lactic Lactic Lactic Lactic MEA MEA MEA solution B acid acid acid acid acid Amt. 2 4 2 4 6 8 10 2 4 6 added (vol %) JET (sec) 80 Measurement 80 80 80 80 80 80 80 Temp S/E (m) 1.41 not 1.51 1.57 1.72 1.83 1.83 1.42 1.31 increased T/A () 52 possible 58 49 53 53 55 52 64 and Mo residue A due to A A A A A A A large Mo undercutting A resist C C C C C C C amount peel off of bubbles produced pH 4.2 4.2 4.0 3.7 3.6 3.4 3.3 4.8 5.4 6.0 BDG: butyl diglycol MEA: monoethanolamine
(87) As shown in Tables 7 to 9, when an organic acid and a diol-based solvent, an alcohol-based solvent, a triol-based solvent, a ketone-based solvent, a nitrogen-containing five-membered ring-based solvent, or a sulfoxide-based solvent were added as a replenisher solution, compared with a case in which only an organic acid was added as a replenisher solution, the effect in suppressing Mo undercutting was large. Furthermore, the use of an organic acid and each of the above solvents as a replenisher solution was effective for Mo undercutting, but the use of a glycol ether-based solvent (butyl diglycol (BDG)), a carboxylic acid-based solvent (lactic acid), or an amine-based solvent (monoethanolamine (MEA)) as a replenisher solution was not effective for Mo undercutting (Tables 10 and 11). Therefore, it has been found that the diol-based solvent, the alcohol-based solvent, the triol-based solvent, the ketone-based solvent, the nitrogen-containing five-membered ring-based solvent, and the sulfoxide-based solvent have an effect in suppressing Mo undercutting. The above solvents are effective not only as a replenisher solution but also when added during preparation of the etching solution composition.
Examples 59 to 77
Etching Test
(88) Etching was carried out in the same way as for Example 1 except that the amount of copper powder shown in Tables 12 to 14 was dissolved in the etching solution composition containing the amine compound and azole compound shown in Tables 12 to 14, and a substrate having the Mo film thickness shown in Tables 12 to 14 was used, the over-etching time being 131 seconds for Examples 59 to 65 and 119 seconds for Examples 66 to 77 (each being 1.7 times when the just-etching time prior to dissolution of copper was defined as a reference).
(89) The results are shown in Tables 12 to 14 and
(90) TABLE-US-00012 TABLE 12 Example Example Example Example Example Example Example 59 60 61 62 63 64 65 (A) Hydrogen peroxide (wt %) 10 10 10 10 10 10 10 (B) Malonic acid (wt %) 5 5 5 5 5 5 5 Succinic acid (wt %) 5 5 5 5 5 5 5 (C) AMP (wt %) 10 10 10 10 10 10 10 (D) ATZ (wt %) 0.02 0.02 0.02 0.02 0.02 0.02 0.02 (E) Phenylurea (wt %) 0.3 0.3 0.3 0.3 0.3 0.3 0.3 Water Remainder Remainder Remainder Remainder Remainder Remainder Remainder Copper powder (ppm) 0 1000 2000 3000 4000 5000 10000 pH 4.4 4.5 4.5 4.5 4.6 4.6 4.6 Cu film thickness/Mo film 5500/300 5500/300 5500/300 5500/300 5500/300 5500/300 5500/300 thickness (/) JET (sec) 77 81 85 88 89 95 100 S/E (m) 1.50 1.50 1.47 1.36 1.32 1.27 1.07 T/A () 40 41 43 44 44 45 47 Mo residue A A A A A A A Mo undercutting A A A B B B C AMP: 2-amino-2-methyl-1-propanol
(91) TABLE-US-00013 TABLE 13 Example 66 Example 67 Example 68 Example 69 Example 70 Example 71 (A) Hydrogen peroxide (wt %) 10 10 10 10 10 10 (B) Malonic acid (wt %) 5 5 5 5 5 5 Succinic acid (wt %) 6.5 6.5 6.5 6.5 6.5 6.5 (C) AMP (wt %) 9.5 9.5 9.5 9.5 9.5 9.5 (D) TA (wt %) 0.01 0.01 0.01 0.01 0.01 0.01 (E) Phenylurea (wt %) 0.3 0.3 0.3 0.3 0.3 0.3 Water Remainder Remainder Remainder Remainder Remainder Remainder Copper powder (ppm) 0 2000 4000 6000 8000 10000 pH 4.1 4.1 4.2 4.2 4.2 4.3 Cu film thickness/Mo film 5500/300 5500/300 5500/300 5500/300 5500/300 5500/300 thickness (/) JET (sec) 70 70 70 70 70 70 S/E (m) 1.35 1.28 1.31 1.18 1.15 1.05 T/A () 35 42 44 47 45 41 Mo residue A A A A A A Mo undercutting A A A A A A TA: 1,2,4-1H-triazole
(92) TABLE-US-00014 TABLE 14 Example 72 Example 73 Example 74 Example 75 Example 76 Example 77 (A) Hydrogen peroxide (wt %) 10 10 10 10 10 10 (B) Malonic acid (wt %) 5 5 5 5 5 5 Succinic acid (wt %) 7 7 7 7 7 7 (C) AMP (wt %) 9.5 9.5 9.5 9.5 9.5 9.5 (D) ATA (wt %) 0.04 0.04 0.04 0.04 0.04 0.04 (E) Phenylurea (wt %) 0.3 0.3 0.3 0.3 0.3 0.3 Water Remainder Remainder Remainder Remainder Remainder Remainder Copper powder (ppm) 0 2000 4000 6000 8000 10000 pH Cu film thickness/Mo film 5500/300 5500/300 5500/300 5500/300 5500/300 5500/300 thickness (/) JET (sec) 70 70 70 70 70 70 S/E (m) 1.14 1.12 1.07 1.06 1.02 1.09 T/A () 49 53 53 51 47 41 Mo residue A A A A A A Mo undercutting A A A A A A ATA: 3-amino-1H-1,2,4-triazole
(93) The S/E of etching solution compositions containing ATZ of Table 12 decreased greatly in response to an increase in the amount of copper dissolved, but the S/E of etching solution compositions containing 1,2,4-1H-triazole of Table 13 decreased slightly, and the S/E of etching solution compositions containing 3-amino-1H-1,2,4-triazole of Table 14 hardly changed. Furthermore, only for the etching solution compositions containing ATZ, Mo undercutting started to occur when the amount of copper dissolved was 3000 ppm.
(94) The main reason for the decrease in S/E was a decrease in the solubility of copper or molybdenum in the etching solution composition; it was necessary to add a replenisher solution in order to maintain the performance in response to an increase in the amount of copper dissolved or to exchange all of the solution while the amount of copper dissolved was still low, but since Mo undercutting did not occur even when the amount of copper dissolved was 10000 ppm, in particular for the etching solution composition containing 1,2,4-1H-triazole or the etching solution composition containing 3-amino-1H-1,2,4-triazole, even when the number of substrates to be treated increases, it is easy to maintain the performance, and it is unnecessary to use a replenisher solution, thus giving many advantages such as the cost being cut.
INDUSTRIAL APPLICABILITY
(95) The etching solution composition of the present invention can be suitably used in the etching of a metal laminate film that contains a layer formed from copper or an alloy having copper as a main component and a layer formed from molybdenum or an alloy having molybdenum as a main component, and the etching method employing the composition enables batch etching of the metal laminate film to be carried out, undercutting of the molybdenum layer to be suppressed, and the cross-sectional shape to be controlled, thus enabling high productivity to be achieved. Furthermore, since the method for extending the life span of the etching composition of the present invention improves the solubility for copper, not only can the life span of the solution be extended, but it is also possible to cut the solution replacement operation and manpower cost and, furthermore, to improve the safety.