CN113614647A

CN113614647A - Resist stripping liquid

Info

Publication number: CN113614647A
Application number: CN201980094569.XA
Authority: CN
Inventors: 渊上真一郎; 鬼头佑典; 小池至人
Original assignee: Panasonic Intellectual Property Management Co Ltd
Current assignee: Panasonic Intellectual Property Management Co Ltd
Priority date: 2019-03-25
Filing date: 2019-03-25
Publication date: 2021-11-05
Also published as: TWI721833B; TW202041984A; JP6684998B1; WO2020194420A1; JPWO2020194420A1

Abstract

By implementing a high-definition broadcast transmission format such as 4K or 8K, the screen of the television becomes large. Therefore, in order to prevent the occurrence of failure in the formation of the device, the baking temperature of the photoresist is increased, and the photoresist is hard to be peeled off. Further, since a large amount of resist stripping liquid is used, a resist stripping liquid having a high regeneration rate is required to reduce the cost. Provided is a resist stripping solution which can strip a hard-baked resist and can also be regenerated by distillation, and is characterized by comprising a 2-stage cyclic amine compound and a 3-stage polyamine compound, and by comprising 0.0001-0.05 mass% of a metal surface protective agent.

Description

Resist stripping liquid

Technical Field

The present invention relates to a resist stripping liquid for stripping a photoresist used in photolithography.

Background

Broadcast transmission formats capable of providing high image quality such as 4K and 8K have been proposed, and test broadcasting has also been started. Accordingly, televisions are also gradually providing large-sized pictures. A liquid crystal television is a mainstream of a television at present, and a transistor corresponding to a pixel is formed on a transparent substrate (glass) for a large screen. The forming utilizes photolithography.

When forming elements on a large screen by photolithography, strict production management that is not allowed by failure of 1 element is performed. Therefore, it is required that peeling of the applied photoresist film, which is directly related to an etching error, does not occur. As a result, the temperature of the baking process (also referred to as a baking process) of the photoresist before exposure tends to increase.

Patent document 1 discloses a photoresist remover composition for removing a photoresist, comprising: 1 or more amine compounds; an aprotic polar solvent, an alkylene glycol monoalkyl ether solvent, or a mixture thereof; 1 or more solvents selected from the group consisting of bis (2-hydroxyethyl) ether, alkylene glycol bis (hydroxyethyl) ether, and [2- (2-hydroxyethoxy) ethoxy ] ethanol; and a corrosion inhibitor comprising a triazole-based compound, a tetrazole-based compound, or 2 structurally specific compounds, wherein the amine compound comprises 1 or more chain amine compounds and 1 or more cyclic amine compounds.

The stripper composition can remove the photoresist which is hard baked at 165 ℃ for 10 minutes without generating stripping residue.

In the photolithography step, etching is performed using a photoresist, and the photoresist after the etching has been completed needs to be stripped. Therefore, the photoresist stripper is consumed in a large amount. It has been experimentally found that the amount of the resist stripping solution used is often more than 1000 t/month, and there are problems such as the cost for purchasing the resist stripping solution, the disposal cost of the used resist stripping solution, and the environmental load when the resist stripping solution is not decomposed and disposed of as it is. Therefore, the photoresist stripper is recycled in the factory for manufacturing large-screen televisions.

Documents of the prior art

Patent document

Patent document 1: japanese patent laid-open publication No. 2016-511843

Disclosure of Invention

Problems to be solved by the invention

As described above, the resist stripping liquid is recycled, and in order to perform the most efficient recycling, it is desirable that the material be suitable for the distillation recycling process. That is, the temperature of the material, which occupies most of the materials used, needs to be in the range of about 150 to 200 ℃. Therefore, not only the stripping ability to completely strip the hard baked photoresist but also the material that is well suited for the distillation regeneration process is required.

Means for solving the problems

The present invention has been made in view of the above problems, and an object of the present invention is to provide a resist stripping solution which can sufficiently strip a hard-baked photoresist and can set the boiling point of a polar solvent occupying the majority of the stripping solution to 200 ℃.

Specifically, the resist stripping solution of the present invention is characterized in that,

comprising a 2-stage cyclic amine compound and a 3-stage polyamine compound,

and contains 0.0001 to 0.15 mass% of a metal surface protecting agent.

ADVANTAGEOUS EFFECTS OF INVENTION

The resist stripping liquid of the present invention uses a polar solvent having a boiling point of 200 ℃ or lower, and has a composition that provides a balance between amines having a strong resist stripping force and corrosion of a metal surface caused by the amines. Therefore, the hard-baked resist film can be sufficiently peeled off, and the polar solvent having the largest proportion can be distilled and regenerated, which contributes to a reduction in production cost.

Detailed Description

The resist stripping liquid of the present invention will be described below with reference to the drawings and examples. In the following description, one embodiment and one example of the present invention are shown by way of example, and the present invention is not limited to the following description. Changes may be made in the following description without departing from the spirit of the invention. In the following description, when a range is expressed, a term "to" is used in some cases, and means "from" to "(including the value and larger to" lower to "including the value and smaller).

The resist stripping solution of the present invention contains an amine compound, a polar solvent and a metal surface protective agent. As the amine compound, a mixture of a 2-stage cyclic amine compound and a 3-stage polyamine compound at a predetermined ratio is used.

The 2-stage cyclic amine compound is a compound in which 2 hydrogen atoms of ammonia are substituted with a hydrocarbon group, and the substituted functional group is bonded in a cyclic shape. Specifically, at least 1 of pyridylalkane, piperidine, piperazine, 4-methylpiperidine, 1-methylpiperazine, 1-methylpiperidine, 2-methylpyrrole and 3-methylpyrrole can be suitably used. The 2-stage cyclic amine compound is preferably contained in an amount of 0.3 to 2.0% by mass, more preferably 0.5 to 1.0% by mass, based on the total amount of the stripping liquid.

The 3-stage polyamine compound is a compound having a plurality of 3-stage amines. Specifically, at least 1 kind of tetramethylethylenediamine, N ' -tetramethyl-1, 3-diaminobutane, N ', N ", N '" -pentamethyldiethylenetriamine, 2-diethyleneaminoethanol, dimethylaminoethanol, trimethylaminomethylethanolamine, and tris (3-aminopropyl) amine can be suitably used. The 3-stage polyamine compound is preferably contained in an amount of 0.5 to 9.0% by mass, more preferably 3.0 to 7.0% by mass, based on the total amount of the stripping liquid.

The amine compound contains more 3-stage polyamine compounds than 2-stage cyclic amine compounds, and the ratio is 3: 1-7: 1 is suitable.

Since the polar solvent is used in the largest amount, it is preferable that the amine compound is capable of being regenerated by distillation and is well dissolved. Especially, a mixture of an amide of an organic polar solvent and water is desirable. Among the amides, those having a linear amide chain and a boiling point of 200 ℃ or lower are preferable. Specifically, at least 1 of N-methylformamide (183 ℃ C.), N-dimethylformamide (153 ℃ C.), N-diethylformamide (177 ℃ C.), N-dimethylacetamide (165 ℃ C.), and N, N-diethylacetamide (185 ℃ C.) can be suitably used. The number in parentheses is the temperature of the boiling point.

Preferably, water is 10 to 30 mass% of the entire stripping solution. The organic polar solvent is preferably the above-mentioned amine compound, water and the balance of the metal surface protecting agent described later.

The metal surface protecting agent is a substance that prevents corrosion of a metal surface such as a copper layer, a molybdenum layer, or an aluminum layer when an amine-based resist is peeled off. The mechanism of corrosion of metal surfaces is not understood. Therefore, it is necessary to determine effective substances by trial and error. The inventors of the present invention could confirm that: in the combination of the amine and the polar solvent, the following substances exert effects.

Specifically, benzotriazole, 5-methyl-1H-benzotriazole, 2-mercaptobenzimidazole, 2-mercaptobenzothiazole, 2-mercapto-5-methylbenzimidazole, 1- [ N, N-bis (2-ethylhexyl) aminomethyl ] -1H-benzotriazole, 2' -methyl-1H-benzotriazol-1-yl-methyliminodiethanol. Therefore, at least 1 substance selected from these compound groups is used as the metal surface protective agent.

The metal surface protecting agent is preferably 0.0001 to 0.15 mass% of the total stripping solution. The metal surface protecting agent exerts its effect in a very small amount. Therefore, if the amount is too large, peeling cannot be performed. However, too little of the metal surface is corroded by the stripping solution.

As described above, it is needless to say that the resist stripping liquid of the present invention contains the amine compound, the polar solvent, and the metal surface protective agent, and the total amount of the components is adjusted so as to be 100 mass%.

Examples

Examples of the resist stripping liquid according to the present invention are shown below. Sample stripping liquids of examples and comparative examples having the compositions shown below were prepared, and a resist stripping test was performed on a resist stripping test piece.

< test piece for resist stripping >

Molybdenum (Mo) was deposited on a silicon substrate at a thickness of 30nm, and copper (Cu) was laminated thereon at a thickness of 500 nm. On which silicon dioxide (SiO) was applied in a thickness of 300nm₂) And (5) laminating. This is referred to as a silicon layer stack.

SiO on silicon layer stack₂Contact holes having a diameter of 1 μm were formed at predetermined positions of the layer. Then, molybdenum (Mo) was further laminated at a thickness of 30nm, and copper (Cu) was further laminated thereon at a thickness of 500 nm.

Next, a positive resist is applied to the copper layer of the uppermost layer, and firing (baking) is performed at a predetermined temperature. The baking was usually performed at 150 ℃ for about 2 minutes, but in order to confirm the peeling force of the resist stripper, the baking was performed at 170 ℃ for 5 minutes. Thereby, the resist film is firmly subjected to the baking treatment. After baking, exposure was performed in the pattern of the gate line and development was performed, and then the copper layer and the molybdenum layer on the upper layer were etched, thereby obtaining a copper test piece for resist stripping.

That is, the copper test piece for resist stripping has a molybdenum layer and a copper layer in which a pattern of a grid line is etched, and a resist film subjected to a baking treatment is deposited thereon. In addition, the resist film also covers the contact hole portion.

Further, aluminum (Al) was laminated on the silicon laminate in a thickness of 500nm, and the aluminum layer was etched in a pattern of a grid line in the same manner as in the resist-stripping copper test piece. The baking treatment was performed at 170 ℃ for 5 minutes in the same manner as the baking treatment of the resist layer. Thus, an aluminum test piece for resist stripping was obtained.

< evaluation >

As the ability to peel off the resist (hereinafter referred to as "peeling force"), each test piece was treated with each sample peeling liquid heated to 40 ℃ for 40 seconds, and the residual state of the resist was confirmed by an optical microscope. Then, when the resist was clearly left on the surface, the evaluation was "x" (meaning of failure or failure), and when the resist was peeled off to a state without any problem, the evaluation was "good" (meaning of pass or success).

As an ability to suppress corrosion of the metal surface (hereinafter referred to as "metal damage"), the corrosion state of the metal film of the test piece after being immersed in the sample stripping solution at 40 ℃ for 4 minutes and treated was observed by SEM (Scanning Electron Microscope). In this observation, the etched portion was observed in a bird's eye view, a surface-enlarged view, and a cross-sectional view.

In a bird's eye view, the corrosion state of the molybdenum layer and the copper layer was confirmed. In the enlarged surface field, the corrosion state of the surfaces of the copper layer and the aluminum layer was confirmed. In particular, the state of copper on the surface of the gate line and at the edge of the contact hole is confirmed. In addition, in the cross-sectional view, the roughness state and the inclination angle of the inclined surface of the etched metal layer were confirmed.

Then, in each field, the evaluation of the state judged as not suitable for production was "x" (meaning of failure or failure), and the evaluation of the state judged as suitable for production was "good" (meaning of passing or success).

< sample stripping solution >

The composition of the stripping solution for each sample is shown. The following compounds are shown below, but the following abbreviations may be used.

Pyridylalkane (pyrolidine): PRL (CAS number: 123-75-1),

Trimethylaminomethylethanolamine (2- [ [2- (Dimethylamino) ethyl ] methylimino ] eth anol): TMEDA (CAS number: 2212-32-0),

N, N '-pentamethyldiethylenetriamine (N, N' -pentanethyldiethylenetriamine): PMDETA (CAS number: 3030-47-5),

Diethyl formamide (N, N-diethyl formamide): DEF (CAS number: 617-84-5), Diethylenetriamine (Diethylenetramine): DETA (CAS number: 111-40-0),

Benzotriazole (1H-Benzotriazole): BTA (CAS number: 95-14-7),

Benzimidazole (benzamidzole): BIZ (CAS number: 51-19-2),

5-methyl-1H-benzimidazole (5-methyllbenzimidazole): 5M1H-BIZ (CAS number: 614-97-1),

Monoethanolamine (Ethanolamine): MEA (CAS number: 141-43-5),

gamma-Butyrolactone (gamma-Butyrolactone): γ -BL (CAS number: 96-48-0).

(example 1)

The sample stripping solution of example 1 was prepared with the following composition.

PRL 1.0g as a 2-stage cyclic amine compound,

5.0g of PMDETA as a 3-stage polyamine compound,

DEF 66.99g as a polar solvent,

27.0g of water,

0.01g of BTA as a metal surface protecting agent,

the above were mixed to prepare a sample stripping solution of example 1.

(example 2)

The sample stripping solution of example 2 was prepared with the following composition.

PRL 1.0g as a 2-stage cyclic amine compound,

5.0g of PMDETA as a 3-stage polyamine compound,

DEF 66.99g as a polar solvent,

27.0g of water,

0.01g of 5MBTA as a metal surface protecting agent,

the above were mixed to prepare a sample stripping solution of example 2.

Comparative example 1

The sample stripping solution of comparative example 1 was prepared with the following composition.

PRL 1.0g as a 2-stage cyclic amine compound,

5.0g of PMDETA as a 3-stage polyamine compound,

DEF 66.91g as a polar solvent,

27.0g of water,

BIZ as a metal surface protecting agent 0.09g,

the above were mixed to prepare a sample stripping solution of comparative example 1.

Comparative example 2

The sample stripping solution of comparative example 2 was prepared with the following composition.

PRL 1.0g as a 2-stage cyclic amine compound,

5.0g of PMDETA as a 3-stage polyamine compound,

DEF 66.91g as a polar solvent,

27.0g of water,

0.09g of 5M1H-BIZ as a metal surface protective agent,

the above were mixed to prepare a sample stripping solution of comparative example 2.

Comparative example 3

The sample stripping solution of comparative example 3 was prepared with the following composition.

PRL 1.0g as a 2-stage cyclic amine compound,

5.0g of PMDETA as a 3-stage polyamine compound,

DEF 66.91g as a polar solvent,

27.0g of water,

Uric acid as a metal surface protecting agent 0.09g,

the above were mixed to prepare a sample stripping solution of comparative example 3.

Comparative example 4

The sample stripping solution of comparative example 4 was prepared with the following composition.

5.0g of PMDATA as a 2-stage cyclic amine Compound,

DETA as a 3-stage polyamine compound (10.0 g),

MEA 5.00g as a polar solvent,

γ-BL 80.0g、

The above were mixed to prepare a sample stripping solution of comparative example 4. In comparative example 4, no metal surface protective agent was contained.

The sample peeling solution was prepared and subjected to a peeling test. The composition of the stripping solution and the results of the stripping test for each sample are shown in table 1.

[ Table 1]

Referring to table 1, in examples 1 and 2 having the composition of the present invention, the resist film subjected to the heat treatment at 170 ℃ for 5 minutes was peeled under the treatment condition of 40 ℃ for 40 seconds. Therefore, the evaluation of the peeling force was good. In addition, in observation by SEM, the state of the copper film in the gate line and the contact hole was also good, and the evaluation of metal damage was also "good". Further, the aluminum layer peel strength was evaluated to be "good".

In the stripping solutions of example 1 and example 2, PRL, water, DEF, and PMDETA can be separated by distillation in this order of temperature. In addition, the temperature of the distillation column at the time of distillation separation is sufficiently about 200 ℃, and almost all of PRL, water, DEF, and PMDETA can be recovered.

On the other hand, in comparative examples 1 to 3, the kind of the metal surface protecting agent was changed. In these examples, the evaluation of the metal damage of the gate line was "good", but the corrosion of the contact hole was large and the evaluation of the metal damage was "x".

The combination of amine compounds in comparative example 4 was different, and thus the polar solvent was also different. In comparative example 4, the resist was not peeled off at all, and the peel force was evaluated as "x". Therefore, the evaluation of the item of metal damage was not performed.

As described above, the resist stripping solution of the present invention can use a material having a low boiling point and capable of being regenerated by distillation, can sufficiently strip a resist film baked at a high temperature, and can further suppress corrosion of the surface of a metal film.

Industrial applicability

The present invention can be suitably used for a resist stripping step in a process for manufacturing a large-area display device.

Claims

1. A resist stripping solution is characterized by comprising a 2-stage cyclic amine compound and a 3-stage polyamine compound, and by comprising 0.0001-0.15 mass% of a metal surface protective agent.

2. The resist stripping liquid according to claim 1, wherein the 2-stage cyclic amine compound comprises at least one of pyridylalkane, piperidine, piperazine, 4-methylpiperidine, 1-methylpiperazine, 1-methylpiperidine, 2-methylpyrrole, and 3-methylpyrrole.

3. The resist stripping solution according to claim 1 or 2, wherein the 3-stage polyamine compound comprises at least one of tetramethylethylenediamine, N ' -tetramethyl-1, 3-diaminobutane, N ', N ", N '" -pentamethyldiethylenetriamine, 2-diethyleneaminoethanol, dimethylaminoethanol, trimethylaminomethylethanolamine, tris (3-aminopropyl) amine.

4. The resist stripping liquid according to any one of claims 1 to 3, further comprising a polar solvent, wherein the polar solvent is a mixture of a linear amide having a boiling point of 200 ℃ or lower and water.

5. The resist stripping liquid according to any one of claims 1 to 4, characterized in that the linear amide comprises at least one of N-methylformamide, N-dimethylformamide, N-diethylformamide (177 ℃), N-dimethylacetamide (165 ℃), and N, N-diethylacetamide (185 ℃).

6. The resist stripping solution according to any one of claims 1 to 5, characterized in that the metal surface protective agent is at least one selected from benzotriazole, 5-methyl-1H-benzotriazole, 2-mercaptobenzimidazole, 2-mercaptobenzothiazole, 2-mercapto-5-methylbenzimidazole, 1- [ N, N-bis (2-ethylhexyl) aminomethyl ] -1H-benzotriazole, and 2, 2' -methyl-1H-benzotriazol-1-yl-methyliminodiethanol.

7. The resist stripping solution according to any one of claims 1 to 5, characterized in that the 2-stage cyclic amine compound is 0.3 to 2 mass%, the 3-stage polyamine compound is 0.5 to 9 mass%, water is 10 to 30 mass%, and the balance is a polar solvent.