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Cleaning liquid used in photolithography and a method for treating substrate therewithRelated Patent Categories: Cleaning Compositions For Solid Surfaces, Auxiliary Compositions Therefor, Or Processes Of Preparing The Compositions, Cleaning Compositions Or Processes Of Preparing (e.g., Sodium Bisulfate Component, Etc.), For Cleaning A Specific Substrate Or Removing A Specific Contaminant (e.g., For Smoker`s Pipe, Etc.), For Printed Or Integrated Electrical Circuit, Or Semiconductor DeviceCleaning liquid used in photolithography and a method for treating substrate therewith description/claimsThe Patent Description & Claims data below is from USPTO Patent Application 20070027052, Cleaning liquid used in photolithography and a method for treating substrate therewith. Brief Patent Description - Full Patent Description - Patent Application Claims
BACKGROUND OF THE INVENTION [0001] 1. Field of the Invention [0002] The present invention relates to a cleaning liquid used in photolithography for stripping and dissolving a thick photoresist pattern, and a method for treating a substrate therewith. The cleaning liquid of the invention is suitably applied especially for the formation of a bump in the production of a semiconductor device, such as IC and LSI. [0003] 2. Description of Related Art [0004] In recent years, with the highly integration of semiconductor devices such as IC and LSI and downsizing of chip size, it has been required to micronize metallic wirings and to align bumps (minute salient electrodes) having a height of 20 .mu.m or more on a substrate with high precision as connection terminals. In future, in conformity to further downsizing of chip size, highly precision of metallic wirings and bumps will become further necessary. [0005] The bump formation is carried out by, for example, providing a metallic thin film on a substrate, forming a thick photoresist pattern on the metallic thin film by photolithography technique, providing a conductive layer on the photoresist pattern-uncovered area (i.e., a metallic thin film-exposed area) of the substrate to form bumps, and then removing the photoresist pattern. [0006] Since the photoresist pattern is formed thickly usually in a film thickness of about 10-150 .mu.m, the photoresist to be used is preferred negative-working photoresist materials in view of resistance to plating, pattern shape property, etc. However, it is difficult in removing photoresist pattern made of the negative-working photoresist materials as compared with the one made of positive-working photoresist materials. Thus, it is much more difficult in removing a thickly formed photoresist pattern made of the negative-working photoresist materials. [0007] Further, during the formation process of the thick photoresist pattern, it is inevitable the pattern is liable to cause deformation in its shape, such as collapse and deficiency, because of its heavy film thickness. In such a case, it is necessary to discontinue the subsequent process and to carry out a re-work by removing away the deformed photoresist pattern from the substrate on the way of the works and do over again the formation of the photoresist pattern process from the first. [0008] In any case of the removal of the photoresist pattern after the bump formation or the removal of the photoresist pattern for the re-work, after the immersion of the substrate having thereon a thick photoresist pattern in a cleaning liquid tank and thereby stripping (falling down) the pattern from the substrate, it is required the stripped-away photoresist pattern (cured material) be rapidly and completely dissolved in the cleaning liquid tank. When the stripped-away photoresist pattern remains in the cleaning liquid tank in a state of being insufficiently dissolved, there is the fear of a re-adhesion of the remaining cured photoresist pattern to the substrate, or in a continuous processing, to the subsequent substrate to be treated, which cause the inefficiency of the production. The prevention of corrosion of the metallic thin film is also required. In addition, in forming a bump on the substrate, a degenerated film is possibly formed at the interface between the photoresist pattern and the bump. It is therefore necessary to prevent the formation of such a degenerated film and to prevent the bump from corrosion. [0009] JP-A-08-301911 describes a radiation-sensitive resin composition as a pattern forming material for the use of a bump formation and discloses in paragraph Nos. [0032] and [0043] a mixture of a quaternary ammonium, dimethyl sulfoxide and water (specifically, a dimethyl sulfoxide solution of 0.5 mass % of tetramethylammonium hydroxide (containing 1.5 mass % of water)) as a stripping liquid for stripping a photo-cured pattern. However, this stripping liquid involves problems such that it takes a time to dissolve the photo-cured pattern that was stripped away from the substrate in the stripping liquid, and that the throughput is low. [0010] JP-A-10-239865 describes a formulation containing specific amounts of dimethyl sulfoxide, 1,3-dimethyl-2-imidazolidinone, a tetraalkylammonium hydroxide, and water as a stripping liquid for stripping a negative-working photoresist for forming a bump. As is the case of JP-A-08-301911 above, JP-A-10-239865 also involves problems such that it takes a time to dissolve the photo-cured pattern that was stripped away from the substrate in the stripping liquid, and that the throughput is low. Further, the stripping solution in JP-A-10-239865 contains 1,3-dimethyl-2-imidazolidinone as an essential component. This compound causes discoloration or corrosion of Cu. [0011] In the photolithographic field, JP-A-2001-324823, JP-A-07-028254, etc., disclose stripping liquids containing a quaternary ammonium hydroxide and a water-soluble organic solvent such as dimethyl sulfoxide. However, none of those describe at all the removability of the hardly removable photoresists that are suitably used for forming a thick pattern for the formation of a bump. SUMMARY OF THE INVENTION [0012] The object of the invention is to provide a cleaning liquid capable of not only stripping a thick photoresist pattern to be used for bump formation, etc., from a substrate but also rapidly and completely dissolving the stripped photoresist pattern without causing re-adhesion to the substrate or the subsequent substrate(s), and a method for treating a substrate using the cleaning liquid. [0013] The present invention is to provide a cleaning liquid for stripping and dissolving a photoresist pattern having a film thickness of 10-150 .mu.m, which contains (a) 0.5-15 mass % of a quaternary ammonium hydroxide represented by the following general formula (I): wherein all groups or at least three groups of R.sub.1, R.sub.2, R.sub.3, and R.sub.4 each independently represents an alkyl group or a hydroxyalkyl group each having 3-6 carbon atoms, and one group of R.sub.1, R.sub.2, R3, and R.sub.4 may represent an alkyl group or a hydroxyalkyl group each having 1-6 carbon atoms, (b) 65-97 mass % of a water-soluble organic solvent, and (c) 0.5-30 mass % of water. [0014] Also, the present invention is to provide a method for treating a substrate, comprising forming a photoresist pattern having a film thickness of 10-150 .mu.m on a substrate having a metallic thin film thereon, providing a conductive layer on a metallic thin film-exposed area or a photoresist pattern uncovered area, and bringing the photoresist pattern into contact with the cleaning liquid to strip and dissolve the photoresist pattern. [0015] Also, the present invention is to provide a method for treating a substrate, comprising forming a photoresist pattern having a film thickness of 10-150 .mu.m on a substrate having a metallic thin film thereon, bringing the photoresist pattern into contact with the cleaning liquid to strip and dissolve the photoresist pattern, without providing a conductive layer on a metallic thin film-exposed area or a photoresist pattern uncovered area. DETAILED DESCRIPTION OF THE INVENTION [0016] The cleaning liquid of the invention is used for stripping and dissolving a photoresist pattern having a film thickness of 10-150 .mu.m, that is formed on a substrate having a metallic thin film thereon. Component (a) in the stripping liquid is a quaternary ammonium hydroxide represented by the following general formula (I): wherein all groups or at least three groups of R.sub.1, R.sub.2, R.sub.3, and R.sub.4 each independently represents an alkyl group or a hydroxyalkyl group each having 3-6 carbon atoms, and one group of R.sub.1, R.sub.2, R.sub.3, and R.sub.4 may represent an alkyl group or a hydroxyalkyl group each having 1-6 carbon atoms. In the case where all groups or at least three groups of R.sub.1, R.sub.2, R.sub.3, and R.sub.4 have less than 3 carbon atoms, corrosion of the metallic thin film (especially, Cu, etc.) occurs. [0017] Specific examples of component (a) include tetrapropylammonium hydroxide, tetrabutylammonium hydroxide, methyltripropylammonium hydroxide, and methyltributylammonium hydroxide. Among all, tetrapropylammonium hydroxide is the most preferable in view of the strippability and solubility of the photoresist pattern (cured pattern) in the cleaning liquid as well as the anti-corrosiveness of an easily corrosive metal such as Cu. Component (a) may be used singly or in admixture of two or more thereof. [0018] The amount of component (a) is 0.5-15 mass %, and preferably 1-10 mass % in the cleaning liquid of the invention. When the amount of component (a) is less than 0.5 mass %, it is difficult to sufficiently remove the photoresist pattern, whereas when it exceeds 15 mass %, a corrosion is liable to occur to the metallic thin film (such as Cu) or an Si substrate. [0019] The water-soluble organic solvent as component (b) may be an organic solvent miscible with water and other compounding components, and conventional cones may be employed. Specific examples include sulfoixdes, such as dimethyl sulfoxide; sulfones, such as dimethylsulfone, diethylsulfone, bis(2-hydroxyethyl)sulfone, and tetramethylenesulfone (i.e., sulforane); amides, such as N,N-dimethylformamide, N-methylformamide, N,N-dimethylacetamide, N-methylacetamide, and N,N-diethylacetamide; lactams, such as N-methyl-2-pyrroldione, N-ethyl-2-pyrrolidone, N-propyl-2-pyrrolidone, N-hydroxymethyl-2-pyrrolidone, and N-hydroxyethyl-2-pyrrolidone; and polyhydric alcohols and derivatives thereof, such as ethylene glycol, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, ethylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether acetate, diethylene glycol, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monopropyl ether, and propylene glycol monobutyl ether. In the present invention, in view of the prevention of corrosion of a metal and the prevention of discoloration, it is undesirable to use imidazolidinones, such as 1,3-dimethyl-2-imidazolidinone, 1,3-diethyl-2-imidazolidinone, and 1,3-diisopropyl-2-imidazolidinone. [0020] As component (b) in the invention, it is preferable to use dimethyl sulfoxide singly or a mixed solvent of dimethyl sulfoxide and other water-soluble organic solvent(s). Among all, it is preferable to use a mixed solvent of dimethyl sulfoxide and N-methyl-2-pyrrolidone and/or sulforane in view of both of the strippability and solubility of the photoresist pattern in the cleaning liquid of the invention and the anti-corrosiveness of Cu. Specifically, a mixed solvent of dimethyl sulfoxide and N-methyl-2-pyrrolidone is the most preferable as its superiorities both in the strippability of the photoresist pattern in the solvent and in the dissolubility of the photoresist pattern in the solvent. The mixing ratio of dimethyl sulfoxide to other water-soluble organic solvent is preferably from about 8/1 to 1/8 (by mass ratio). Component (b) may be used singly or in admixture of two or more thereof. [0021] The amount of component (b) is 65-97 mass %, and preferably 70-96 mass % in the cleaning liquid of the invention. When the amount of component (b) is less than 65 mass %, corrosion of the metallic thin film, the bumps, and the Si substrate is liable to occur, whereas when it exceeds 97 mass %, the strippability and solubility of the photoresist pattern in the cleaning liquid is lowered. Continue reading about Cleaning liquid used in photolithography and a method for treating substrate therewith... 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