JP5195063B2 - Resist stripper - Google Patents

Description

  The present invention relates to a stripping solution for positive photoresist.

  Lithography is generally used as a method for manufacturing semiconductor integrated circuits, liquid crystal displays, plasma displays, organic EL displays, and printed wiring boards. When manufacturing by a lithography method, after forming an oxide film etc. on a board | substrate, a photoresist is uniformly apply | coated to the surface and this is selectively exposed. In the case of a positive type photoresist, a resist pattern is formed by developing with a basic substance. Next, the lower layer thin film is selectively etched using this resist pattern as a mask to form a pattern, and then a series of steps of completely removing the resist on the substrate with a resist stripping solution is performed.

  Conventionally known resist stripping solutions include, for example, a solution composed of hydroxide ions and ammonium ions (see, for example, Patent Document 1), a stripping solution composed of an alkanolamine such as monoethanolamine and an organic solvent (for example, Patent Document 2), a stripping solution using a quaternary ammonium salt (for example, see Patent Document 3), and the like.

  By the way, although molybdenum oxide is known as a substance useful as a hole injection material in the manufacture of an organic EL display (for example, refer to Patent Document 4), this molybdenum oxide is a hydroxide, monoethanolamine, Since it is very easy to dissolve in a liquid containing a strong base such as a quaternary ammonium salt, when the resist is removed with the liquid as described above, molybdenum oxide is damaged and its film thickness is reduced. There have been problems such as rough surface conditions. For this reason, a useful resist stripping solution is required in the production of an organic EL display using molybdenum oxide as a material, but a useful stripping solution has not been developed yet.

  On the other hand, a method using morpholine, which is a weak base, or a morpholine derivative as a resist stripping solution has been proposed (see, for example, Patent Document 5 and Patent Document 6). However, morpholine and morpholine derivatives have only been developed as stripping solutions that do not damage aluminum, and stripping solutions that are useful for manufacturing organic EL displays using molybdenum oxide as a material have not been developed yet.

JP-T-2002-505448 JP 62-234373 A US Pat. No. 5,185,235 JP-A-9-63771 JP 58-80638 A Japanese Unexamined Patent Publication No. Sho 63-110454

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a stripping solution for removing a positive photoresist after forming a photoresist pattern without damaging molybdenum oxide. It is in.

  As a result of intensive studies on a stripping solution for removing positive photoresist on a substrate on which molybdenum oxide is exposed or on a substrate in which a photoresist pattern is formed on molybdenum oxide, The present inventors have found that a resist containing an amine can remove the resist without corroding the molybdenum oxide and have completed the present invention.

  That is, the present invention is a composition for removing a positive photoresist on molybdenum oxide, and a stripping solution for positive photoresist containing N- (2-hydroxyethyl) morpholine and an organic solvent, and This is a method for stripping a positive type photoresist.

  The resist stripping solution of the present invention is extremely useful industrially because it can clean and remove the positive photoresist after forming a resist pattern without corroding molybdenum oxide in the manufacture of flat panel displays such as organic EL displays. is there.

  The essential components of the resist stripper of the present invention are N- (2-hydroxyethyl) morpholine and an organic solvent.

  In the resist stripping solution of the present invention, the N- (2-hydroxyethyl) morpholine used is not particularly limited, and those that are generally available can be used, but flat panel displays such as organic EL displays can be used. In the production, it is preferable to use one having a low metal ion content.

  In the resist stripping solution of the present invention, the organic solvent to be used is not particularly limited, and generally used ones can be used. However, if a solvent having high resist stripping ability is exemplified, the alcohol solvent is methyl alcohol, ethyl alcohol, 1-propyl alcohol, 2-propyl alcohol, ethylene glycol, propylene glycol, glycerin, 1,6-hexanediol, As ether solvents, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol mono Butyl ether, dipropylene glycol As monomethyl ether, dipropylene glycol monoethyl ether, dipropylene glycol monobutyl ether, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, dipropylene glycol dimethyl ether, dipropylene glycol diethyl ether, triethylene glycol, tetraethylene glycol, polyethylene glycol, amide solvents, Formamide, N-methylformamide, N, N-dimethylformamide, N-ethylformamide, N, N-diethylformamide, acetamide, N-methylacetamide, N, N-dimethylacetamide, N-ethylacetamide, N, N-diethyl Acetamide, N-methylpyrrolidone, sulfur-containing solvents such as dimethylsulfone, dimethyl Sulfoxides, sulfolane, as imidazolidinone solvents, 1,3-dimethyl-2-imidazolidinone, 1,3-diethyl-2-imidazolidinone, and lactone-based solvents include γ- butyrolactone. These organic solvents may be used alone or in combination of two or more.

  Water can be further added to the resist stripping solution of the present invention. By adding water, handling of the resist stripping solution can be facilitated. By adding water, the melting point of the organic solvent having a high melting point can be lowered, and the flash point can be raised.

  Carboxylic acid can be further added to the resist stripping solution of the present invention. By adding carboxylic acid, the basicity of the resist stripping solution can be adjusted, the dissolution of molybdenum oxide can be suppressed, and the resist stripping ability can be enhanced.

  The carboxylic acid that can be added to the resist stripping solution of the present invention is not particularly limited, but for example, formic acid, acetic acid, propionic acid, lactic acid, oxalic acid, malic acid, malonic acid, citric acid, glutaric acid and the like can be mentioned. It is done. These acids may be used singly or in combination of two or more. In addition, since these acids have high solubility in the resist stripping solution, they can be used preferably. However, other acids may be used if they dissolve in the resist stripping solution.

  The resist stripping solution of the present invention changes the resist stripping property and the amount of damage to the molybdenum oxide depending on the acidity and basicity. For example, if the basicity is too strong, damage to the molybdenum oxide is increased, and if the acidity is too strong, the resist peelability is lowered and damage to materials other than the molybdenum oxide is increased. The acidity and basicity are preferably in the range of 4 to 11, more preferably in the range of 4.5 to 10.5, when the resist stripping solution of the present invention is diluted 10 times with water.

  The resist stripping solution of the present invention is preferably in the range of 1 to 80% by weight of N- (2-hydroxyethyl) morpholine and in the range of 99 to 20% by weight of organic solvent, based on the entire stripping solution. More preferably, (2-hydroxyethyl) morpholine is in the range of 5 to 70% by weight, and the organic solvent is in the range of 95 to 30% by weight. By making N- (2-hydroxyethyl) morpholine 1% by weight or more, the resist stripping property is improved, and by making N- (2-hydroxyethyl) morpholine 80% by weight or less, the resist stripping solution is washed with water. When doing so, it becomes difficult for the stripping solution to remain on the substrate surface. Moreover, resist peelability improves by making an organic solvent 99 weight% or less and 20 weight% or more.

  When water and / or carboxylic acid is added to the resist stripping solution of the present invention, it is preferable that water is in the range of 0 to 80% by weight and carboxylic acid is in the range of 0 to 20% by weight with respect to the entire stripping solution. More preferably, the water is in the range of 0 to 70% by weight and the carboxylic acid is in the range of 0 to 10% by weight. Regardless of whether the water content exceeds 80% by weight or the carboxylic acid content exceeds 20% by weight, the resist stripping property may decrease.

  The resist stripping solution of the present invention is used as a stripping solution for removing a positive photoresist on molybdenum oxide after forming a resist pattern in, for example, a manufacturing process of a flat panel display such as an organic EL display.

  The positive photoresist removed by the resist stripper of the present invention is not particularly limited as long as it is generally used in the manufacturing process of flat panel displays such as organic EL displays. And those based on novolac resin or polyimide resin.

  Since the resist stripping solution of the present invention does not damage the molybdenum oxide, the positive photo resist which is no longer necessary on the substrate where the molybdenum oxide is exposed or on the substrate where the photoresist pattern is formed on the molybdenum oxide. When removing the resist, excellent peeling ability can be exhibited.

  Since the resist stripping solution of the present invention has a very high resist stripping property, it can be used sufficiently even at low temperatures, but the operating temperature is preferably in the range of 0 to 100 ° C. If it is less than 0 ° C., the cleaning rate is unrealistically slow, and if it exceeds 100 ° C., the evaporation and evaporation of the organic solvent and water become severe, which is not practical.

  The resist stripping solution of the present invention can be used without any problem in either a batch type or single wafer type cleaning method, and cleaning by spraying or other methods may be used. Furthermore, ultrasonic waves can be used in combination as necessary. For rinsing after removing the positive photoresist on the object to be processed, it is not necessary to use an organic solvent such as alcohol, and it is sufficient to rinse with water.

  The present invention will be described in more detail with reference to the following examples, but the present invention is not limited thereto. In order to simplify the notation, the following abbreviations were used.

HEM: N- (2-hydroxyethyl) morpholine MO: Molybdenum oxide MEA: Monoethanolamine DMSO: Dimethyl sulfoxide NMP: N-methylpyrrolidone γ-BL: γ-butyrolactone BEE: Butoxyethoxyethanol TMAH: Tetramethylammonium hydroxide EGEE: ethylene glycol monoethyl ether DEGEE: diethylene glycol monoethyl ether DB: 1,2-dichlorobenzene DMF: N, N′-dimethylformamide MOR: morpholine CA: citric acid OA: oxalic acid AA: acetic acid Examples 1-3 Reference Examples 1-5 , Comparative Examples 1-3:
(Cleaning evaluation)
After development and etching, the substrate having the novolak photoresist layer that was no longer needed was immersed in the stripping solution described in Tables 1 and 2 at room temperature for 5 minutes. This was washed with water and dried, and the degree of cleaning was confirmed. Those that could be washed were evaluated as “◯”, and those that could not be washed were evaluated as “×”. The results are shown in Tables 1 and 2.

(MO damage)
An MO film was formed to a thickness of 0.1 μm on a glass substrate. This board | substrate was immersed in the washing | cleaning liquid of Table 1 and Table 2 for 5 minutes at room temperature. This was washed with water and dried, and the surface was observed with SEM. The case where the surface state changed compared to before the treatment was evaluated as “×”, and the case where the surface state did not change was evaluated as “◯”. The results are shown in Tables 1 and 2.

Claims (6)

A stripping solution for positive photoresist, which is a composition for removing a positive photoresist on molybdenum oxide, and includes N- (2-hydroxyethyl) morpholine , an organic solvent, and a carboxylic acid . An organic solvent is an alcohol solvent such as methyl alcohol, ethyl alcohol, 1-propyl alcohol, 2-propyl alcohol, ethylene glycol, propylene glycol, glycerin, 1,6-hexanediol, an ether solvent such as ethylene glycol monomethyl ether, Ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monobutyl ether, dipropylene glycol monomethyl ether, dipropylene Glycol mono Cyl ether, dipropylene glycol monobutyl ether, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, dipropylene glycol dimethyl ether, dipropylene glycol diethyl ether, triethylene glycol, tetraethylene glycol, polyethylene glycol, amide solvents such as formamide, N-methylformamide, N , N-dimethylformamide, N-ethylformamide, N, N-diethylformamide, acetamide, N-methylacetamide, N, N-dimethylacetamide, N-ethylacetamide, N, N-diethylacetamide, N-methylpyrrolidone, Sulfur solvents include dimethyl sulfone, dimethyl sulfoxide, sulfolane, and imidazolidinone. As 1,3-dimethyl-2-imidazolidinone, 1,3-diethyl-2-imidazolidinone, and a lactone solvent, one or more selected from the group consisting of γ-butyrolactone The stripping solution according to claim 1. The stripping solution according to claim 1 or 2, further comprising water. The carboxylic acid is at least one or two or more selected from the group consisting of formic acid, acetic acid, propionic acid, lactic acid, oxalic acid, malic acid, malonic acid, citric acid, and glutaric acid. The stripping solution according to any one of claims 3 to 3 . The stripping solution according to any one of claims 1 to 4 , wherein the pH when diluted 10-fold with water is in the range of 4-11. The positive photoresist on the substrate on which the molybdenum oxide is exposed or on the substrate in which the photoresist pattern is formed on the molybdenum oxide is removed with the stripper according to any one of claims 1 to 5. A positive photoresist stripping method characterized by the above.