JP2016095413A - Resist removal liquid - Google Patents

Abstract

PROBLEM TO BE SOLVED: To resolve a problem that a hard baked resist film cannot be removed by a shared resist removal liquid capable of removing a resist film on a Cu film, a Cu/Mo film and an Al film because the hard baked resist film proceeds a polymerization of a novolac resin and a DNQ compound more than necessary and strongly fixes to a backing metal film.SOLUTION: There is provided a resit removal liquid containing cyclic amine, a polar solvent, water, sugar alcohol and a reductant, especially using at least one of pyrrolidine or compound where a substitute binds to a 3-position of pyrrolidine as the cyclic amine and hydrazine as the reductant.SELECTED DRAWING: None

Description

  The present invention is a stripping solution for stripping a resist used in the manufacture of display devices such as liquid crystal and organic EL and semiconductors. More specifically, even a hard-baked resist film can remove a resist, and further, aluminum The present invention also relates to a resist stripper that can be said to be substantially free from corrosion even with respect to a film and a copper film.

  A flat panel display (FPD) such as a liquid crystal or an organic EL (Electro-Luminescence) is required to have a large screen. On the other hand, small high-definition screens are required for notebook PCs, tablet PCs, and smartphones. For large screens, TFTs (Thin Film Transistors) using Cu wiring or Cu / Mo laminated wiring (hereinafter also simply referred to as “Cu wiring”) are used. In addition, TFTs using Al wiring are used for small high-definition screens. Hereinafter, Cu is also called copper, Mo is called molybdenum, and Al is also called aluminum.

  Some panel manufacturers produce TFTs using Al wiring and TFTs using Cu wiring in one factory. When both TFTs using Al wiring and TFTs using Cu wiring are produced, the resist stripping solution can be shared between the case of using Al wiring and the case of using Cu wiring in the resist film peeling process. If possible, production costs can be reduced.

  The aqueous positive photoresist stripping solution is generally composed of alkanolamine, a polar solvent, and water, and is heated to about 40 to 50 ° C. in a resist stripping apparatus.

  Alkanolamine is an essential component for solubilizing the carbonyl group of a DNQ (diazonaphthoquinone) compound, which is an alkali insolubilizing agent, in a positive photoresist stripping solution in a polar solvent and water by nucleophilic action. Alkanolamines are classified as primary, secondary, and tertiary depending on the number of substituents other than hydrogen bonded to the nitrogen element. Among these, it is known that the smaller the series, the stronger the basicity and the stronger the nucleophilicity.

  Therefore, the smaller the series, the stronger the ability to solubilize the DNQ compound, which is an alkali insolubilizing agent, in a polar solvent or water, and a stronger resist stripping performance.

  On the other hand, alkanolamines are known to have a chelating action on Cu. The chelating action for Cu solubilizes Cu and thus corrodes the Cu film. The chelating action for Cu is stronger as the alkanolamine series is smaller as is the case with basicity and nucleophilicity. Therefore, the alkanolamine with a smaller series corrodes the Cu film more strongly.

  In the production process of high-definition screen TFTs using Al wiring, the resist is damaged and denatured in the dry etching process of semiconductor (amorphous silicon: hereinafter also referred to as “a-Si”), and the resist is peeled off. May be difficult. This is presumably because the polymerization of the DNQ compound and the novolak resin constituting the positive resist film proceeds excessively.

  The Al wiring does not receive a corrosive action (chelating action) caused by alkanolamine. Therefore, in order to remove the modified resist, it is common to use a primary alkanolamine having strong release performance.

  On the other hand, in the case of Cu wiring, when primary or secondary alkanolamine is used, corrosion of Cu wiring often occurs to an unacceptable level. Therefore, a stripping solution using a tertiary alkanolamine has been proposed. Tertiary alkanolamines have a weak chelating action on Cu, and can suppress the corrosion of the Cu film to a practically acceptable range. However, the basicity and nucleophilicity are weak as well as the chelating action, and there is a drawback that the resist stripping force is weak compared to a resist stripping solution using a primary or secondary alkanolamine.

  Under such a technical background, there is a need for a resist stripping solution composition that has a stripping performance equivalent to or better than that of a resist stripping solution for Al wiring using primary alkanolamine and can be used for both Cu wiring and Al wiring. It has been.

  Patent Document 1 discloses a resist stripping solution containing a compound represented by the formula (1) and a solvent. It is said that this resist stripper can also be used in the resist stripping process for Cu wiring and Al wiring.

Japanese Patent No. 5279921

  The resist film is used when a wiring or the like is formed through an etching process after being exposed and developed. Here, a step called post-bake is passed before the etching step. This is performed for the purpose of making the resist film harder before etching is performed. By this post-baking, the polymerization of the novolak resin constituting the resist film and the DNQ compound as the alkali insolubilizer proceeds further, and the resist film is prevented from peeling from the surface of the metal film during the etching process.

  However, in this post-baking process, if the heating temperature rises too much (hard bake state), the polymerization of the novolak resin and DNQ compound that occurs in the resist film proceeds so much that the conventional resist stripping solution cannot be stripped. .

  In this regard, Patent Document 1 has studied hard baking, and it is said that the resist can be stripped even under conditions of hard baking at 160 ° C. for 5 minutes. Therefore, it is said that the stripping solution of Patent Document 1 can strip the resist even in the case of an unexpected situation that may occur during the manufacture of hard baking.

  However, the compound of the formula (1) has a problem that it is a special compound that is not commercially available as a reagent or an industrial raw material.

  The present invention has been conceived in view of the above problems, and even if a problem of hard baking occurs in the manufacturing process, Cu that can peel off the resist film after etching without stopping the manufacturing line. The present invention provides a resist stripping solution that can be used in a stripping process for wiring and Al wiring.

More specifically, the resist stripper according to the present invention is:
It contains a cyclic amine, a polar solvent, water, a sugar alcohol, and a reducing agent. Further, a high boiling point solvent may be included.

  The resist stripping solution according to the present invention can be used in common in the resist stripping process for Cu wiring (including Cu / Mo laminated wiring) and Al wiring. Further, even if the resist film is hard-baked, the resist film can be peeled off. In addition, the resist stripping solution according to the present invention can strip the resist film that has been hard-baked in this way, while also damaging the Cu film, the Mo film disposed as the base of the Cu film, and the Al film. There is no.

  Therefore, even if it is a resist film on an aluminum film or a resist film on a Cu film, it can be stripped with one kind of resist stripping solution. That is, it is not necessary to prepare a plurality of types of resist film stripping process lines, and the resist stripping solution may be managed in one type. Also, a process called ashing is not necessary. As a result, it is possible to contribute greatly to productivity and cost reduction in the factory.

  In addition, since the resist stripping solution according to the present invention contains sugar alcohol, the sugar alcohol having the highest boiling point among the components may solidify in the distillation tower as the last residue when performing distillation regeneration. However, by including a high-boiling solvent having a boiling point that remains as a residue together with the sugar alcohol, solidification in the distillation tower can be suppressed even when the sugar alcohol remains as a residue.

It is a figure explaining the taper angle and Mo undercut of a Cu / Mo laminated film.

  Hereinafter, the resist stripping solution according to the present invention will be described. The following description shows an embodiment of the photoresist stripping solution according to the present invention, and the following embodiments and examples may be modified without departing from the gist of the present invention.

  The resist film from which the resist stripping solution according to the present invention is peeled assumes a positive resist. The positive resist includes a novolac resin as a resin, and a diazonaphthoquinone (DNQ) compound is used as a photosensitive agent. When etching is performed, a resist film is formed on the substrate, and exposure is performed through the pattern.

  This exposure turns the DNQ compound into indenketene. When indenketene associates with water, it turns into indenecarboxylic acid and dissolves in water. The novolac resin originally has a property of being dissolved in an alkaline solution, but the melting point is protected by a DNQ compound. The DNQ compound is altered by exposure and dissolved in a developer containing water, so that the novolak resin is also dissolved. In this way, patterning of the resist film is completed.

  The substrate on which the patterning is completed with the resist film is subjected to wet etching or dry etching processing through post-baking. Post bake is performed in order to advance polymerization of the novolak resin and the DNQ compound in the resist film to some extent. Usually, the heat treatment is performed at 140 ° C. for about 5 minutes. In this specification, hard baking refers to heating conditions at 150 ° C. for 5 minutes or more. When the baking temperature rises, the novolak resin and the DNQ compound rapidly polymerize and firmly adhere to the underlying metal film, making it difficult to dissolve. The resist stripping solution according to the present invention is also intended for a resist film that has undergone such hard baking.

  The resist stripping solution according to the present invention includes a cyclic amine, a polar solvent, water, and an additive. The additive includes a sugar alcohol and a reducing agent. Further, a high boiling point solvent may be included.

  The polar solvent may be an organic solvent having an affinity for water. Examples of such water-soluble organic solvents include sulfoxides such as dimethyl sulfoxide; sulfones such as dimethyl sulfone, diethyl sulfone, bis (2-hydroxyethyl) sulfone, and tetramethylene sulfone; N, N-dimethylformamide, N-methyl Amides such as formamide, N, N-dimethylacetamide, N-methylacetamide, N, N-diethylacetamide; N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, N-propyl-2-pyrrolidone, N -Lactams such as hydroxymethyl-2-pyrrolidone and N-hydroxyethyl-2-pyrrolidone; 1,3-dimethyl-2-imidazolidinone, 1,3-diethyl-2-imidazolidinone, 1,3-diisopropyl -2-imidazolidinones such as imidazolidinone; 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 monopropyl ether, diethylene glycol monobutyl ether Propylene glycol monoalkyl ether such as diethylene glycol monoalkyl ether, propylene glycol, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monopropyl ether, propylene glycol monobutyl ether Ruki ethers (alkyl is a lower alkyl group having 1 to 6 carbon atoms) are exemplified polyvalent alcohols, and derivatives thereof, and the like.

  Among these, at least one selected from dimethyl sulfoxide, N-methyl-2-pyrrolidone, and diethylene glycol monobutyl ether, and at least one mixed liquid selected from ethylene glycol, diethylene glycol, and propylene glycol are preferable. Available. In particular, for a positive resist, a desired result can be obtained by using a mixed liquid of diethylene glycol monobutyl ether (BDG) and propylene glycol (PG) as a polar solvent.

  In the resist stripping solution according to the present invention, a mixed solution of diethylene glycol monobutyl ether (BDG) and propylene glycol (PG) can be suitably used as a polar solvent. These polar solvents dissolve and facilitate dissolution of the resist film. In particular, propylene glycol swells the resist film, and diethylene glycol monobutyl ether (BDG) dissolves the resist film. Therefore, a polar solvent containing at least two liquids is effective.

  In addition, the resist stripping solution according to the present invention can contain a high-boiling solvent having a similar boiling point remaining as a residue together with the sugar alcohol described later. The high boiling point solvent desirably has a higher boiling point than the component used as the polar solvent. Further, the high boiling point solvent is preferably one that can dissolve the sugar alcohol and the resist component. Furthermore, it is desirable that it can be easily dissolved in water. Accordingly, polyols having a high boiling point can be suitably used. When the resist stripping solution is regenerated by distillation, the sugar alcohol and the resist component remain as the last residue. This is to prevent these residues from solidifying at that time.

  For example, if the polar solvents that can be suitably used are propylene glycol (boiling point 188 ° C.) and diethylene glycol monobutyl ether (boiling point 230 ° C.), a solvent having a boiling point higher than 230 ° C. is used. In this case, specific high boiling point solvents include polyols such as glycerin (boiling point 290 ° C.), diethylene glycol (boiling point 244 ° C.), 1,5-pentanediol (boiling point 242 ° C.), 1,6-hexanediol (boiling point). 250 ° C.), 1,7-heptanediol (boiling point 258 ° C.), 1,10-decanediol (boiling point 297 ° C.) and the like.

  Further, ethers in polyols include ethylene glycol monophenyl ether (boiling point 245 ° C.), triethylene glycol monomethyl (boiling point 249 ° C.), diethylene glycol dibutyl ether (boiling point 256 ° C.), triethylene glycol butyl methyl ether (boiling point). 261 ° C.), polyethylene glycol dimethyl ether (boiling point 264 to 294 ° C.), tetraethylene glycol dimethyl ether (boiling point 275 ° C.), polyethylene glycol monomethyl ether (boiling point 290 to 310 ° C.) and the like.

  The polar solvent is preferably 50 to 80% by mass with respect to the total amount of the resist stripping solution. In addition, when using a high boiling point solvent together, it is suitable to contain 1-5 mass% of high boiling point solvents.

  As the cyclic amine, a 5-membered cyclic amine is desirable, and in particular, pyrrolidine or one having a substituent bonded to the 3-position of pyrrolidine is desirable. For example, 3-methylpyrrolidine, (S) -3-ethylpyrrolidine, 3-aminopyrrolidine, 3-acetamidopyrrolidine, 3- (N-acetyl-N-ethylamino) pyrrolidine, 3- (N-acetyl-N-methylamino) ) Pyrrolidine, (R) -3-hydroxypyrrolidine, and 3- (ethylamino) pyrrolidine are preferably used. These cyclic amines are effective in removing a hard-baked resist film. In addition, pyrrolidine is generally distributed as a fragrance such as an intermediate for medicines and agricultural chemicals and gum, and is an easily available compound. Therefore, the cost of the stripping solution itself can be reduced.

  The addition amount of the cyclic amine is preferably in the range of 0.5% by mass or more and less than 2.0% by mass relative to the total amount of the resist stripping solution. More desirably, it is 0.8 mass% or more and 1.5 mass% or less. If the amount of cyclic amine is too large, the copper film and the molybdenum film are corroded, and if it is too small, the resist film that has undergone hard baking cannot be removed.

  Sugar alcohol and a reducing agent are added as additives. As the sugar alcohol, sorbitol, xylitol, sucrose, mannitol, maltitol, lactitol and the like can be suitably used. These sugar alcohols suppress the dissolution of the Al film in the resist stripping solution and, together with the reducing agent (hydrazine), suppress the undercut of the Mo film.

  Moreover, 0.5-10 mass% of sugar alcohol is suitable with respect to resist stripping solution whole quantity. More desirably, the content is 0.8 to 2.0% by mass. Sugar alcohol has a role as a corrosion inhibitor. Therefore, it is desirable to contain a certain amount. However, it does not contribute much to the resist film peeling. On the other hand, when the sugar alcohol is excessively added, when the resist stripping solution is distilled and regenerated, it remains in the distillation column and causes scaling. Therefore, it is good to contain in said range.

  As the reducing agent, hydrazine can be suitably used. The addition of the reducing agent suppresses Mo undercut by the cyclic amine. The reducing agent is preferably in the range of 0.03 to 0.4 mass% with respect to the total amount of the resist stripping solution. More preferably, it is the range of 0.06-0.2 mass%. Hydrazine may be hydrated from the viewpoint of safe handling.

  Examples and comparative examples of resist stripping solutions according to the present invention are shown below. The resist stripping solution was evaluated for two points: “resist strippability” and “corrosiveness of metal film”.

<Resist peelability>
A silicon thermal oxide film having a thickness of 100 nm was formed on a silicon substrate, and a copper film having a thickness of 300 nm was formed on the silicon thermal oxide film by sputtering. A positive resist solution was applied onto the copper film by spin coating to prepare a resist film. After the resist film was dried, it was exposed using a wiring pattern mask. Then, the resist in the exposed portion was removed with a developer. That is, there is a state where there is a portion where the resist film of the wiring pattern remains on the copper film and a portion where the copper film is exposed.

  Thereafter, the entire silicon substrate was post-baked at 150 ° C. for 10 minutes. This is a process of reproducing hard baking.

  Next, the exposed copper film was removed by etching using a superaqueous copper etchant. After the etching of the copper film was completed, the resist film on the remaining copper pattern was stripped using a sample resist stripping solution. The time for removing the resist film was examined in three stages, 40 seconds, 80 seconds, and 120 seconds. Then, the substrate was washed, and it was observed while interfering with an optical microscope whether or not the resist film remained on the copper film. When the remainder of the resist film was confirmed on the copper film, it was set to “x” (X), and when the remaining resist film was not confirmed, it was set to “◯” (maru). Note that “◯” (maru) means success or success, and “x” (cross) means failure or failure. The same applies to the following evaluations.

<Corrosiveness of metal film>
The corrosivity of the metal film was evaluated as follows. First, a silicon thermal oxide film was formed to a thickness of 100 nm on a silicon substrate, and a copper film was formed to a thickness of 300 nm on the silicon thermal oxide film by sputtering to prepare a Cu film sample. This is called “Cu gate”. Similarly, a molybdenum film was formed to a thickness of 20 nm on a silicon thermal oxide film on a silicon substrate, and a copper film was subsequently formed to a thickness of 300 nm to prepare a Cu / Mo laminated film sample. . This is called “Cu / Mo gate”. In addition, an aluminum film was formed to a thickness of 300 nm on the silicon thermal oxide film on the silicon substrate to produce an Al film sample. This is called “Al gate”.

  A resist patterned into a wiring shape was formed on these evaluation samples, and used as a base material for corrosive evaluation. In other words, the base material for corrosivity evaluation is a resist formed in a wiring shape on a Cu film, Cu / Mo film, or Al film formed on a silicon thermal oxide film on a silicon substrate. Consists of layers.

  Etching was performed by immersing these corrosive evaluation base materials in an etchant for copper film or aluminum film for the time of just etching. Thereafter, the substrate for corrosion evaluation after etching was immersed in a sample resist stripper for 6 minutes to strip the resist film. After the corrosive evaluation base material immersed in the sample resist stripping solution for 6 minutes was washed and dried, the wiring portion was cut and the cut surface was observed.

  In the evaluation of corrosivity, the resist film is not subjected to heat treatment until it is in a hard bake state. Moreover, the judgment of just etching was made when the silicon thermal oxide film was visually confirmed from the start of etching.

  The observation of the cut surface was performed using SEM (Scanning Electron Microscope) (Hitachi: SU8020 type) under the conditions of an acceleration voltage of 1 kV and 30,000 to 50,000 times.

  The cut surface shape is shown in FIG. FIG. 1A shows a cut surface shape in the case of Cu Gate and Al Gate. The cut surface shape of the just-etched portion has a taper angle 5 of approximately 30 ° to 60 ° with respect to the substrate 1. The film part 2 is a Cu film in the case of Cu Gate, and an Al film in the case of Al Gate.

  FIG. 1B shows the case of Cu / Mo Gate. In the case of Cu / Mo Gate, at least the upper Cu layer 2 has a taper angle 5. The underlying Mo layer 3 is preferably etched along the tapered surface 6 of the Cu layer. However, as shown in FIG. 1B, there may be an etching residue 7 from the Cu layer.

  Corrosivity is evaluated as “×” (X) if corrosion is confirmed on either the film part 2 or the surface 4 of the film part 2 or the underlying Mo layer 3 by observing the cross-sectional shape. When no corrosion was observed, it was judged as “◯” (maru).

  In particular, in the case of Cu / Mo Gate, corrosion may occur between the underlying Mo layer 3 and Cu layer 2 as shown in FIG. That is, Mo dissolution starts from the interface between the copper layer 2 and the molybdenum layer 3 and the molybdenum layer 3 may be selectively etched earlier than the copper layer 2. Therefore, when the gap 10 could be confirmed between the Mo layer 3 and the Cu layer 2, the evaluation was “x” (X).

<Sample resist stripper>
A sample resist stripping solution was prepared as follows. The sample resist stripping solution is composed of a cyclic amine, a polar solvent, water, and an additive.

(1) Example 1
A 5-membered cyclic amine was used as the cyclic amine.
Pyrrolidine (PRL) 0.8% by mass
Two types of polar solvents were mixed.
Propylene glycol (PG) 27.6% by mass
Diethylene glycol monobutyl ether (BDG) 40.0% by mass
Water 30.0% by mass
Sugar alcohol and a reducing agent were added as additives.
Sorbitol (Stol) 1.5% by mass
Hydrazine monohydrate (HN) 0.1% by mass
The above was mixed and stirred to obtain the sample resist stripping solution of Example 1.

  In addition, 0.1 mass% of hydrazine monohydrate corresponds to 0.064 mass% of hydrazine. The remaining 0.036% by mass of hydrazine monohydrate is water. Therefore, it can be said that the composition ratio of the above water is 30.036% by mass including the amount added as hydrazine monohydrate. In the following examples and comparative examples, the same notation is used when hydrazine monohydrate is used.

(2) Example 2
Example 2 increased the amount of cyclic amine. As the cyclic amine, pyrrolidine, a five-membered cyclic amine, was used.
Pyrrolidine (PRL) 1.5% by mass
Two types of polar solvents were mixed.
Propylene glycol (PG) 26.9% by mass
Diethylene glycol monobutyl ether (BDG) 40.0% by mass
Water 30.0% by mass
Sugar alcohol and a reducing agent were added as additives.
Sorbitol (Stol) 1.5% by mass
Hydrazine monohydrate (HN) 0.1% by mass
The above was mixed and stirred to obtain the sample resist stripping solution of Example 2.

(3) Example 3
In Example 3, the type of cyclic amine was changed.
3- (Ethylamino) pyrrolidine (EAPRL) was used as a 5-membered cyclic amine.
3- (Ethylamino) pyrrolidine (EAPRL) 1.5% by mass
Two types of polar solvents were mixed.
Propylene glycol (PG) 26.9% by mass
Diethylene glycol monobutyl ether (BDG) 40.0% by mass
Water 30.0% by mass
Sugar alcohol and a reducing agent were added as additives.
Sorbitol (Stol) 1.5% by mass
Hydrazine monohydrate (HN) 0.1% by mass
The above was mixed and stirred to obtain the sample resist stripping solution of Example 3.
In addition, 3- (ethylamino) pyrrolidine is a compound represented by the following formula (2).

(4) Example 4
In Example 4, glycerin was further added to the polar solvent of Example 1.
A 5-membered cyclic amine was used as the cyclic amine.
Pyrrolidine (PRL) 0.8% by mass
Three types of polar solvents were mixed.
Propylene glycol (PG) 25.6% by mass
Diethylene glycol monobutyl ether (BDG) 40.0% by mass
Glycerin 2.0% by mass
Water 30.0% by mass
Sugar alcohol and a reducing agent were added as additives.
Sorbitol (Stol) 1.5% by mass
Hydrazine monohydrate (HN) 0.1% by mass
The above was mixed and stirred to obtain a sample resist stripping solution of Example 4.

(5) Example 5
In Example 5, glycerin was further added to the polar solvent of Example 2.
A 5-membered cyclic amine was used as the cyclic amine.
Pyrrolidine (PRL) 1.5% by mass
Three types of polar solvents were mixed.
Propylene glycol (PG) 24.9% by mass
Diethylene glycol monobutyl ether (BDG) 40.0% by mass
Glycerin 2.0% by mass
Water 30.0% by mass
Sugar alcohol and a reducing agent were added as additives.
Sorbitol (Stol) 1.5% by mass
Hydrazine monohydrate (HN) 0.1% by mass
The above was mixed and stirred to obtain a sample resist stripping solution of Example 5.

(6) Example 6
In Example 6, glycerin was further added to the polar solvent of Example 3.
3- (Ethylamino) pyrrolidine (EAPRL) was used as a 5-membered cyclic amine.
3- (Ethylamino) pyrrolidine (EAPRL) 1.5% by mass
Three types of polar solvents were mixed.
Propylene glycol (PG) 24.9% by mass
Diethylene glycol monobutyl ether (BDG) 40.0% by mass
Glycerin 2.0% by mass
Water 30.0% by mass
Sugar alcohol and a reducing agent were added as additives.
Sorbitol (Stol) 1.5% by mass
Hydrazine monohydrate (HN) 0.1% by mass
The above was mixed and stirred to obtain a sample resist stripping solution of Example 6.

  Table 1 shows the results of the sample resist stripping composition and the “resist stripping properties” and “corrosiveness of the metal film” for Examples 1 to 6 described above.

(7) Comparative Example 1
Comparative Example 1 is a composition obtained by increasing the amount of cyclic amine in Example 1.
As the cyclic amine, pyrrolidine, a five-membered cyclic amine, was used.
Pyrrolidine (PRL) 2.0% by mass
Two types of polar solvents were mixed.
Propylene glycol (PG) 26.4% by mass
Diethylene glycol monobutyl ether (BDG) 40.0% by mass
Water 30.0% by mass
Sugar alcohol and a reducing agent were added as additives.
Sorbitol (Stol) 1.5% by mass
Hydrazine monohydrate (HN) 0.1% by mass
The above was mixed and stirred to obtain a sample resist stripping solution of Comparative Example 1.

(8) Comparative Example 2
The comparative example 2 was set as the composition which excluded the sorbitol additive with respect to Example 2 (PRL = 1.5 mass%).
As the cyclic amine, pyrrolidine, a five-membered cyclic amine, was used.
Pyrrolidine (PRL) 1.5% by mass
Two types of polar solvents were mixed.
Propylene glycol (PG) 28.4% by mass
Diethylene glycol monobutyl ether (BDG) 40.0% by mass
Water 30.0% by mass
As a additive, only a reducing agent was added.
Hydrazine monohydrate (HN) 0.1% by mass
The above was mixed and stirred to obtain a sample resist stripping solution of Comparative Example 2.

(9) Comparative Example 3
The comparative example 3 changed the kind of reducing agent added as an additive with respect to Example 2 (PRL = 1.5 mass%).
As the cyclic amine, pyrrolidine, a five-membered cyclic amine, was used.
Pyrrolidine (PRL) 1.5% by mass
Two types of polar solvents were mixed.
Propylene glycol (PG) 26.9% by mass
Diethylene glycol monobutyl ether (BDG) 40.0% by mass
Water 30.0% by mass
Sugar alcohol and a reducing agent were added as additives. Monomethylhydrazine was used as the reducing agent.
Sorbitol (Stol) 1.5% by mass
Monomethylhydrazine (MMHN) 0.1% by mass
The above was mixed and stirred to obtain a sample resist stripping solution of Comparative Example 3.

(10) Comparative Example 4
The comparative example 4 changed the kind of reducing agent added as an additive with respect to Example 2 (PRL = 1.5 mass%).
As the cyclic amine, pyrrolidine, a five-membered cyclic amine, was used.
Pyrrolidine (PRL) 1.5% by mass
Two types of polar solvents were mixed.
Propylene glycol (PG) 26.9% by mass
Diethylene glycol monobutyl ether (BDG) 40.0% by mass
Water 30.0% by mass
Sugar alcohol and a reducing agent were added as additives. As the reducing agent, acetohydrazide was used.
Sorbitol (Stol) 1.5% by mass
Acetohydrazide (AHD) 0.1% by mass
The above was mixed and stirred to obtain a sample resist stripping solution of Comparative Example 4.

(11) Comparative Example 5
The comparative example 5 changed the kind of reducing agent added as an additive with respect to Example 2 (PRL = 1.5 mass%).
As the cyclic amine, pyrrolidine, a five-membered cyclic amine, was used.
Pyrrolidine (PRL) 1.5% by mass
Two types of polar solvents were mixed.
Propylene glycol (PG) 26.9% by mass
Diethylene glycol monobutyl ether (BDG) 40.0% by mass
Water 30.0% by mass
Sugar alcohol and a reducing agent were added as additives. As the reducing agent, hydrazine carbonate was used.
Sorbitol (Stol) 1.5% by mass
Hydrazine carbonate (HC) 0.1% by mass
The above was mixed and stirred to obtain a sample resist stripping solution of Comparative Example 5.

(12) Comparative Example 6
The comparative example 6 changed the kind of reducing agent added as an additive with respect to Example 2 (PRL = 1.5 mass%).
As the cyclic amine, pyrrolidine, a five-membered cyclic amine, was used.
Pyrrolidine (PRL) 1.5% by mass
Two types of polar solvents were mixed.
Propylene glycol (PG) 26.9% by mass
Diethylene glycol monobutyl ether (BDG) 40.0% by mass
Water 30.0% by mass
Sugar alcohol and a reducing agent were added as additives. Carbohydrazide was used as the reducing agent.
Sorbitol (Stol) 1.5% by mass
Carbohydrazide (CHD) 0.1% by mass
The above was mixed and stirred to obtain a sample resist stripping solution of Comparative Example 6.

  Table 2 shows the composition of the sample resist stripping solution and the results of “resist stripping property” and “corrosiveness of metal film” for Comparative Examples 1 to 6 described above.

  Next, the following comparative examples were prepared as samples for confirming the effectiveness of a specific cyclic amine in the resist stripping solution according to the present invention.

(13) Comparative Example 7
Comparative Example 7 used 5-membered cyclic amine 2-methylpyrrolidine. There is no additive added.
2-Methylpyrrolidine 2.0% by mass
Two types of polar solvents were mixed.
Propylene glycol (PG) 28.0% by mass
Diethylene glycol monobutyl ether (BDG) 40.0% by mass
Water 30.0% by mass
The above was mixed and stirred to obtain a sample resist stripping solution of Comparative Example 7.

(14) Comparative Example 8
In Comparative Example 8, 5-membered cyclic amine 1-methylpyrrolidine was used. There is no additive added.
1-methylpyrrolidine 2.0% by mass
Two types of polar solvents were mixed.
Propylene glycol (PG) 28.0% by mass
Diethylene glycol monobutyl ether (BDG) 40.0% by mass
Water 30.0% by mass
The above was mixed and stirred to obtain a sample resist stripping solution of Comparative Example 8.

(15) Comparative Example 9
Comparative Example 9 used a 5-membered cyclic amine 2-methoxymethylpyrrolidine. There is no additive added.
2-Methoxymethylpyrrolidine 2.0% by mass
Two types of polar solvents were mixed.
Propylene glycol (PG) 28.0% by mass
Diethylene glycol monobutyl ether (BDG) 40.0% by mass
Water 30.0% by mass
The above was mixed and stirred to obtain a sample resist stripping solution of Comparative Example 9.

(16) Comparative Example 10
In Comparative Example 10, 5-membered cyclic amine 3- (ethylamino) pyrrolidine was used. There is no additive added.
3- (Ethylamino) pyrrolidine 2.0% by mass
Two types of polar solvents were mixed.
Propylene glycol (PG) 28.0% by mass
Diethylene glycol monobutyl ether (BDG) 40.0% by mass
Water 30.0% by mass
The above was mixed and stirred to obtain a sample resist stripping solution of Comparative Example 10.

(17) Comparative Example 11
In Comparative Example 11, pyrrolidine, a five-membered cyclic amine, was used. There is no additive added.
Pyrrolidine 2.0% by mass
Two types of polar solvents were mixed.
Propylene glycol (PG) 28.0% by mass
Diethylene glycol monobutyl ether (BDG) 40.0% by mass
Water 30.0% by mass
The above was mixed and stirred to obtain a sample resist stripping solution of Comparative Example 11.

  Table 3 shows the composition of the sample resist stripping solution and the results of “resist stripping property” and “corrosiveness of metal film” for Comparative Examples 7 to 11 described above.

  In Tables 1 to 3, each% represents mass% with respect to the total amount of the resist stripping solution. PG represents propylene glycol, and BDG represents diethylene glycol monobutyl ether.

  Reference is made to Examples 1 to 3 in Table 1 and Comparative Examples 1 to 6 in Table 2. When the cyclic amine (pyrrolidine) of Examples 1 and 2 and Comparative Example 1 (Table 2) is seen, the resist stripping time is shortened as the cyclic amine increases. On the other hand, referring to Comparative Example 1 (Table 2), the sample resist stripping solution prepared by adding 2.0% by mass of pyrrolidine is “Cu / Mo gate”, that is, a laminated film of Mo film and Cu film, and Mo undercut. Was recognized. That is, pyrrolidine is less than 2.0% by mass, preferably 1.5% by mass or less, based on the total amount of the resist stripping solution.

  Further, even in Example 1 (0.8% by mass of pyrrolidine) which took the longest stripping time, the hard-baked resist film could be stripped in a short time of 120 seconds after immersion.

  In Example 3, the cyclic amine was replaced with 3- (ethylamino) pyrrolidine. In Example 3, the hard-baked resist film was peeled off in 80 seconds, and the problems of corrosion of the metal film and undercut of the Mo film were not caused.

  Reference is made to Comparative Example 2 in Table 2. Comparative Example 2 has a composition containing 1.5% by mass of pyrrolidine and no sorbitol, which is a sugar alcohol. In Comparative Example 2, the Mo film was undercut, and the Al film was corroded. That is, it can be said that sugar alcohol is essential when pyrrolidine is used in the resist stripping solution according to the present invention.

  Comparative Examples 3 to 6 in Table 2 show cases where the reducing agent is changed to four types of monomethyl hydrazine, acetohydrazide, hydrazine carbonate, and carbohydrazide, respectively, instead of hydrazine. Monomethylhydrazine and acetohydrazide produced Mo undercut.

  On the other hand, hydrazine carbonate and carbohydrazide did not cause corrosion of the metal film, but the hard-baked resist film could not be peeled off. This is presumed that the dissolution of the resist film by pyrrolidine is suppressed by the reaction between carbonic acid and pyrrolidine to form carbamate ions of pyrrolidine and the carbamate ions bind to the DNQ of the resist film.

  Refer to Table 3. Table 3 shows the effect of certain five-membered cyclic amines. Comparative Example 7 has 2-methylpyrrolidine having a substituent bonded at the 2-position, Comparative Example 8 has 1-methylpyrrolidine bonded with a substituent at the 1-position, and Comparative Example 9 has 2-position. 2-methoxymethylpyrrolidine having a substituent bonded to position 3, 3- (ethylamino) pyrrolidine having a substituent bonded to position 3 in Comparative Example 10, and pyrrolidine having no substituent bonded to Comparative Example 11 Was used.

  The 3- (ethylamino) pyrrolidine (Comparative Example 10) and pyrrolidine (Comparative Example 11) used in the examples were able to peel off the hard-baked resist film in 40 to 80 seconds. On the other hand, 1-methylpyrrolidine (Comparative Example 8), 2-methylpyrrolidine (Comparative Example 7) and 2-methoxymethylpyrrolidine (Comparative Example 9) having a methyl group bonded to the 1-position and 2-position are Even after 120 seconds, the hard-baked resist film could not be removed.

  From the above, it is concluded that pyrrolidine having a substituent bonded to the 1-position and 2-position of pyrrolidine cannot peel the hard-baked resist film within a practical range.

  On the other hand, pyrrolidine with a substituent at the 3-position, such as 3- (ethylamino) pyrrolidine (Comparative Example 10), or ordinary pyrrolidine to which no substituent is bonded (Comparative Example 11) is hard-baked. The resist film thus obtained could be peeled off. It can be said that Examples 1 to 3 have compositions prepared by adjusting such pyrrolidine and 3- (ethylamino) pyrrolidine so that Mo undercut does not occur.

  Referring to Table 1 again, Examples 4 to 6 were obtained by adding 2.0% by mass of glycerin to the polar solvents of Examples 1 to 3. In these examples, the hard-baked resist film could be peeled off in 80 to 120 seconds, and the Cu gate and Al gate were not damaged, and Mo undercut was not caused.

  That is, it can be practically used as a resist stripping solution. Furthermore, since the resist stripping solutions of Examples 4 to 6 contain glycerin having a high boiling point, sugar alcohol and stripped resist components can be prevented from solidifying in the distillation tower when regenerating by distillation after use.

  As described above, the resist stripping solution according to the present invention includes a cyclic amine, a polar solvent, water, a sugar alcohol, and a reducing agent, so that the resist stripping process for the Cu film, the Cu / Mo film, and the Al film is performed. Can be used in common. Furthermore, even if the resist film is hard-baked, it can be peeled off.

  The resist stripping solution of the present invention can be suitably used as a resist stripping solution when a positive resist is used. This can be suitably used for general production of FPD such as a liquid crystal display, a plasma display, and an organic EL.

1 Substrate 2 Film part 3 Mo layer (underlayer)
4 Surface 5 (of film part 2) Taper angle 6 Tapered surface 7 Etching remaining 10 Clearance

Claims (10)

  A resist stripping solution comprising a cyclic amine, a polar solvent, water, a sugar alcohol, and a reducing agent.   The resist stripping solution according to claim 1, wherein the cyclic amine is a five-membered cyclic amine.   The resist stripping solution according to claim 2, wherein the five-membered cyclic amine has pyrrolidine or a substituent at the 3-position of pyrrolidine.   The resist stripping solution according to claim 3, wherein the pyrrolidine having a substituent at the 3-position is 3- (ethylamino) pyrrolidine.   The resist stripping solution according to any one of claims 1 to 4, wherein the cyclic amine is contained in an amount of 0.5% by mass or more and less than 2.0% by mass with respect to the total amount.   The resist stripping solution according to any one of claims 1 to 5, wherein the sugar alcohol is sorbitol.   The resist stripping solution according to claim 1, wherein the reducing agent is hydrazine. The cyclic amine is 0.5 mass% or more and less than 2.0 mass%,
The polar solvent is 50 to 80% by mass,
The water is 10-50% by mass,
The sugar alcohol is 0.5 to 10% by mass,
The resist removing solution according to claim 1, wherein the reducing agent is 0.03 to 0.4 mass%.   Furthermore, it has glycerol, The resist stripping solution described in any one of Claims 1 thru | or 7 characterized by the above-mentioned. The cyclic amine is 0.5 mass% or more and less than 2.0 mass%,
The polar solvent is 50 to 80% by mass,
The glycerin is 1-5% by mass,
The water is 10-50% by mass,
The sugar alcohol is 0.5 to 10% by mass,
The resist stripping solution according to claim 9, wherein the reducing agent is 0.03 to 0.4 mass%.