JP5590364B2 - Photoresist stripping composition - Google Patents

Description

  The present invention relates to a photoresist stripping composition for removing a photoresist in a process of manufacturing a semiconductor, LED or LCD element.

  In general, a microcircuit of a semiconductor, LED, or LCD element is manufactured through a series of lithography processes. The lithography process is desired by forming a metal layer or an insulating layer on the substrate, applying a photoresist on the metal layer, and selectively irradiating the photoresist with light through a patterned mask. The process of forming the photoresist of this pattern, and the process of developing are included. In this process, the pattern of the metal layer or the insulating layer is formed by dry or wet etching using the photoresist pattern as a mask, and the photoresist pattern is removed by a peeling process.

  The photoresist is classified into two types, that is, a positive type photoresist and a negative type photoresist, depending on the change in solubility in a developer due to light irradiation. A positive photoresist is a type of photoresist in which the exposed portion of the photoresist is soluble in the developer, and a negative photoresist is a photo in which the exposed portion of the photoresist is insoluble in the developer. The type of resist.

  The positive photoresist can be easily removed by a general stripping solution in a general wet process. However, removal of the photoresist becomes difficult if it is cured or modified during the dry etching or ion implantation process. The dry etching process is preferable for forming a fine pattern due to the ease of pattern control and the ability to produce anisotropic pattern transfer. However, the dry etching process uses a gas phase-solid phase reaction between the plasma gas and a material layer such as a conductive layer, and eventually the ions and radicals of the plasma gas react with the photoresist, and thereby the photoresist. Cures and denatures. In addition, the ion implantation process in the manufacturing process of a semiconductor, LED, or LCD device is a process of providing dopant atoms such as phosphorus, arsenic, boron, etc., in order to impart conductivity to a specific region of a silicon wafer, and as a result Type photoresists can be modified by chemically reacting with the ions.

  On the other hand, the negative photoresist is used in a lift-off process. The exposed portions of the negative photoresist become insoluble by crosslinking and therefore cannot be removed sufficiently using common solvents, and the cleaning process is severe such as high temperatures above 100 ° C. and long immersion times. Carried out under various conditions.

A variety of aqueous stripping solutions have been proposed to remove the hardened and modified photoresist during the dry etching or ion implantation process. For example, a stripping solution composition containing hydroxylamines, alkanolamines and water (JP-A-4-289866); a stripping composition containing hydroxylamines, alkanolamines, water and a corrosion inhibitor (JP-A-6-6) No. 266119); stripping composition comprising polar solvents (such as gamma-butyllactone, dimethylformamide, dimethylacetamide, N-methylpyrrolidone, etc.), amino alcohols (such as 2-methylaminoethanol) and water Product (Japanese Patent Laid-Open No. 7-69618); stripping composition containing alkanolamines (such as monoethanolamine / aminoethoxyethanol), hydroxylamine, diethylene glycol monoalkyl ether, saccharide (sorbitol) and water 9-152721); Hydroxylamines in beauty, water, amines pKa7.5 to 13, stripping liquid composition containing a water-soluble organic solvents and corrosion inhibitors such as (JP-A-9-69611) have been reported. But,
Although the above composition is useful for stripping a positive photoresist that has been crosslinked or modified, the ability to strip a negative photoresist is not sufficient.

  Acid strippers or alkaline strippers have been used in the past to remove negative photoresist. A stripping solution containing an alkylbenzene sulfonate, a phenolic compound, a chlorinated solvent, and an aromatic hydrocarbon is a typical acidic stripping solution, but has an insufficient ability to strip a negative photoresist. Furthermore, an alkaline stripping solution containing a water-soluble organic amine and an organic solvent does not have sufficient ability to strip a negative photoresist, but also causes metal corrosion.

  In order to solve this problem, a stripping composition containing hydrazine, a polar organic solvent, an alkaline compound and water is proposed in Korean Patent No. 718527. However, this compound has a good ability to peel off the negative photoresist, but it is not sufficient in preventing corrosion of the metal wiring under the photoresist.

  Recently, as the process for manufacturing semiconductors, LEDs and LCD elements has become more refined and complicated, the process uses both positive and negative photoresists and negative photoresists. obtain. Thus, if there is no common stripper for both positive and negative photoresists, individual strippers and process equipment are required, resulting in increased manufacturing costs and time. Therefore, there is a need for a stripping solution composition that can effectively remove both positive and negative photoresists that do not cause corrosion of metal wiring under the photoresist layer.

JP-A-4-289866 JP-A-6-266119 JP-A-7-69618 JP-A-9-152721 JP-A-9-69611 Korean Registered Patent No. 718527

  SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a stripping solution composition that has an excellent stripping force between a positive photoresist and a negative photoresist and that does not corrode metal wiring under the photoresist layer.

  In accordance with one embodiment of the invention, alkylammonium hydroxide 0.5 to 5% by weight; aprotic polar solvent 60 to 90% by weight; aromatic polyhydric alcohol 0.1 to 3% by weight; linear polyhydric alcohol A photoresist stripper composition comprising 0.1 to 5% by weight; and 5 to 30% by weight of water is provided.

  The photoresist stripping composition according to the present invention has an excellent stripping force for a positive photoresist cured and modified by a dry etching or ion implantation process and a negative photoresist used in a lift-off process, and stripping. The metal wiring under the photoresist layer is not corroded during the process and the ultrapure water rinsing process.

For example, alkylammonium hydroxides for use in the compositions of the present invention include tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrapropylammonium hydroxide and mixtures thereof. The positive photoresist cured and modified by the dry etching, etching or ion implantation process and the negative photoresist crosslinked in the exposure process are not dissolved in the solvent because they are crosslinked inside. Therefore, it is necessary to change the cross-linked photoresist to a soluble form by using an alkaline component to break the cross-link.

  The content of alkylammonium hydroxide is preferably 0.5 to 5% by weight based on the total weight of the composition. If the content of the alkyl ammonium hydroxide is less than 0.5% by mass, it is difficult to cut the modified and cross-linked polymer chain, so that the effect of stripping the photoresist is reduced, and it reduces the content by 5% by mass. If so, the relative content of the aprotic solvent is reduced, thereby reducing the solubility of the photoresist and increasing the corrosion of the underlying metal film.

  The aprotic polar solvent of the composition of the present invention is N, N-dimethylformamide, N, N-dimethylacetamide, N, N′-diethylacetamide, dimethylsulfoxide, N-methylformamide, N, N′-dimethyllactam. It may be amide, N-methylpyrrolidone, γ-butyrolactone, propylene carbonate, 1,3-dimethyl-2-imidazolidinone and mixtures thereof.

  The content of aprotic polar solvent can be 60-90% by weight based on the total weight of the composition. If the content of aprotic polar solvent is less than 60% by weight, the solubility in photoresist is reduced, and if it exceeds 90% by weight, the relative content of water is reduced, thereby causing alkylammonium The activity of the hydroxide is reduced and the ability to strip modified or crosslinked positive and negative photoresists is reduced.

  The water content in the composition is preferably in the range of 5 to 30% by weight based on the total weight of the composition. When the water content is less than 5% by mass, the degree of dissociation of the alkylammonium hydroxide is lowered, resulting in a decrease in the ability to strip the modified or crosslinked positive and negative photoresists. When the water content exceeds 30% by mass, the activity of the alkylammonium hydroxide becomes too high, thereby causing an insufficient corrosion preventing power for the lower metal film.

  Of the main components of the composition of the present invention, the aromatic polyhydric alcohol and the linear polyhydric alcohol serve as corrosion inhibitors.

  The content of the aromatic polyhydric alcohol is preferably 0.1 to 3% by mass based on the total mass of the composition. When the content of the aromatic polyhydric alcohol is less than 0.1% by mass, the corrosion resistance against the lower metal film is reduced, and when it exceeds 3% by mass, the remaining corrosion inhibitor itself causes a defect in the subsequent process. .

  The content of the linear polyhydric alcohol is preferably 0.1 to 5% by mass based on the total mass of the composition. When the content of the linear polyhydric alcohol is less than 0.1% by mass, the corrosion resistance against the lower metal film is reduced, and when it exceeds 5% by mass, the remaining corrosion inhibitor itself causes a defect in the subsequent process. Let

  The aromatic polyhydric alcohol and the linear polyhydric alcohol preferably have at least three hydroxy groups. If the number of hydroxy groups is less than 3, the adsorption power of such alcohols to the metal surface will be low and may cause insufficient corrosion protection. The aromatic polyhydric alcohol corrosion inhibitor preferably has at least one carboxyl group or alkyl ester group. If the number of carboxyl groups or alkyl ester groups is less than one, migration of the metal to the surface is reduced, which may result in insufficient corrosion protection.

  Examples of aromatic polyhydric alcohols include gallic acid, methyl gallate, ethyl gallate, propyl gallate, butyl gallate and mixtures thereof, and examples of linear polyhydric alcohols are glycerol, erythritol, sorbitol , Mannitol, xylitol and mixtures thereof.

  The composition of the present invention exhibits an excellent anticorrosion effect thanks to the synergistic effect obtained by the combined use of an aromatic polyhydric alcohol and a linear polyhydric alcohol. In order to remove the modified and crosslinked photoresist, an alkaline compound such as an alkyl ammonium hydroxide is required, and the addition of the alkaline compound to the stripper composition increases the pH of the composition. The high pH composition causes corrosion of the lower metal layer during the stripping and rinsing process, so a corrosion inhibitor is required. In the high pH region, the aromatic polyhydric alcohol and the linear polyhydric alcohol exhibit excellent corrosion prevention performance.

  In general, corrosion protection is achieved by adsorption of a corrosion inhibitor on the metal surface. During adsorption, the plurality of corrosion inhibitors are adsorbed on the metal surface and form a molecular layer thereon. The performance of the corrosion inhibitor depends on the adsorption power to the metal surface and the density of the molecular layer, and the corrosion prevention performance improves as the adsorption power and the density of the molecular layer increase.

  The aromatic polyhydric alcohol corrosion inhibitor forms a resonance structure with the benzene ring while hydrogen atoms dissociate from the hydroxy group, and thereby adsorbs to the metal as a rigid plate-like structure. The linear polyhydric alcohol corrosion inhibitor does not form a resonance structure even if the hydrogen atom of its hydroxy group is dissociated, and thereby adsorbs to the metal as a flexible chain structure. Therefore, although a linear polyhydric alcohol has a low adsorption power, it has an advantage that it is adsorbed to a fine part because of its small adsorption area. As the tendency of the corrosion inhibitor in the stripping solution to move to the metal surface (surface transferability) becomes larger, the number of corrosion inhibitors adsorbed on the metal surface increases, and a high corrosion inhibitory force is generated.

  Aromatic polyhydric alcohols and linear polyhydric alcohols exhibit different corrosion protection properties due to differences in their metal adsorption structures. The aromatic polyhydric alcohol corrosion inhibitor can be strongly adsorbed on the metal surface due to its plate-like resonance structure, but has a low molecular layer density due to its rigid structure. A linear polyhydric alcohol corrosion inhibitor has a high molecular layer density due to its flexible chain structure, but such a structure cannot be strongly adsorbed to a metal and therefore cannot be strongly adsorbed to a metal surface.

  In order to achieve excellent corrosion protection, the corrosion inhibitor must strongly adsorb to the metal surface and the density of the molecular layer formed thereby must be large. Due to the strong adsorption performance of aromatic polyhydric alcohols to metals and the performance of linear polyhydric alcohols adsorbed on fine parts where aromatic polyhydric alcohols cannot adsorb, aromatic polyhydric alcohols and linear polyhydric alcohols The combined use of polyhydric alcohols retains the performance for stripping the photoresist and provides favorable corrosion protection over the entire metal layer. On the other hand, when an aromatic polyhydric alcohol or a linear polyhydric alcohol is used alone, it is not possible to obtain excellent corrosion prevention while maintaining the performance for stripping the photoresist. When used alone, many corrosion inhibitors are required to obtain corrosion prevention performance, and the relative content of polar solvents is reduced, which results from the low solubility of the corrosion inhibitor in the composition As a result, the performance of the stripping composition for solubilizing the photoresist deteriorates, or it becomes difficult to use the composition.

  The composition of the present invention may further contain glycols and triazoles depending on the desired purpose as long as the effects of the present invention are not impaired.

Suitable glycols include, but are not limited to, diethylene glycol methyl ether, diethylene glycol ethyl ether, diethylene glycol butyl ether, dipropylene glycol methyl ether, hexylene glycol, polyethylene glycol having a weight average molecular weight of 100 to 400, and the like, and Suitable triazoles include, but are not limited to, benzotriazole, carboxybenzotriazole, 1-hydroxybenzotriazole, nitrobenzotriazole, dihydroxypropylbenzotriazole and the like.

  As described above, the photoresist stripping composition according to the present invention is excellent in stripping a positive photoresist cured or modified by a dry etching or ion implantation process and a negative photoresist used in a lift-off process or the like. It has performance and does not corrode the metal wiring under the photoresist layer during the peeling process and the ultrapure water rinsing process. In particular, due to the synergistic effect resulting from the aromatic polyhydric alcohol corrosion inhibitor and the linear polyhydric alcohol corrosion inhibitor, the excellent corrosion inhibition effect is achieved without reducing the ability to strip the photoresist. It can be obtained only by using a small amount of a corrosion inhibitor.

EXAMPLES The following examples are intended to further illustrate the invention, but the invention is not limited to this range.

Examples 1 to 9 and Comparative Examples 1 to 21
The compositions of Examples 1 to 9 and Comparative Examples 1 to 21 were prepared by mixing with the compositions shown in Table 1.
The mixing was performed at room temperature for at least 1 hour so that the solid corrosion inhibitor was completely dissolved and filtered through a Teflon filter.

Test Examples The peel strength and corrosion resistance of the compositions obtained in Examples 1 to 9 and Comparative Examples 1 to 21 were evaluated as follows.

(1) Production of Positive Photoresist Test Sample A positive photoresist (THMR-iP 330, manufactured by TOK) was coated on a silicon nitride-coated silicon wafer, and then a photoresist pattern was formed by an exposure and development process. This pattern was transferred to the silicon nitride layer under the photoresist by a dry etching process to obtain a positive photoresist layer test sample.

(2) Manufacture of negative photoresist test sample A negative photoresist (PMER N-HC600, manufactured by TOK) was coated on a silicon wafer, and then a photoresist pattern was formed by exposure, development and baking processes. Aluminum and titanium were sequentially applied onto a silicon wafer to obtain a lift-off negative photoresist test sample.

Test Example 1 Evaluation of Peeling Force The test composition is maintained at 60 ° C. and a positive photoresist test sample and a negative photoresist test sample are immersed therein for 20 minutes, followed by washing with deionized water for 30 seconds and using nitrogen. And dried. The residual photoresist of the dried sample was observed under an optical microscope (magnification: x200) and FE-SEM (magnification: x10,000 to x50,000).

Test Example 2 Evaluation of corrosion protection The test composition was maintained at 60 ° C. and a negative photoresist test sample was immersed therein for 90 minutes. The resulting sample was washed with deionized water for 30 seconds and then dried with nitrogen for 10 seconds. The degree of corrosion of the dried sample on the surface and cut surface was observed under FE-SEM (magnification: x10,000 to x50,000). In this test example, in order to investigate the difference in the degree of corrosion, corrosive conditions more severe than normal peeling conditions for 20 minutes were used.

As can be seen from Table 1 above, Examples 1 to 9 according to the present invention showed excellent performance for stripping positive and negative photoresists and did not corrode Al / Ti as the lower metal film. . On the other hand, Comparative Examples 1 to 21 outside the scope of the present invention showed low peel strength and increased corrosion.

  Although the invention has been described with reference to the above particular embodiments, it can be made by a person skilled in the art to the invention that various modifications and changes are also within the scope of the invention as defined by the appended claims. It should be recognized.

Claims (6)

Alkylammonium hydroxide 0.5 to 5% by weight;
60 to 90% by weight of aprotic polar solvent;
0.1 to 3% by mass of an aromatic polyhydric alcohol selected from the group consisting of gallic acid, methyl gallate, ethyl gallate, propyl gallate, butyl gallate, and mixtures thereof ;
A photoresist stripping composition comprising 0.1 to 5% by mass of a linear polyhydric alcohol selected from the group consisting of glycerol, erythritol, sorbitol, mannitol, xylitol, and mixtures thereof ; and 5 to 30% by mass of water. The photoresist stripping composition according to claim 1, wherein the alkylammonium hydroxide is selected from the group consisting of tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrapropylammonium hydroxide, and mixtures thereof. . The aprotic polar solvent is N, N-dimethylformamide, N, N-dimethylacetamide, N, N′-diethylacetamide, dimethylsulfoxide, N-methylformamide, N, N′-dimethyllactamamide, N-methyl. The photoresist stripping composition according to claim 1, selected from the group consisting of pyrrolidone, γ-butyrolactone, propylene carbonate, 1,3-dimethyl-2-imidazolidinone, and mixtures thereof. The photoresist stripping composition according to claim 1, further comprising glycols and triazoles. The glycol, diethylene glycol methyl ether, diethylene glycol ethyl ether, diethylene glycol butyl ether, dipropylene glycol methyl ether, claim 4 hexylene glycol, weight average molecular weight is selected from the group consisting of polyethylene glycol and mixtures thereof of 100 to 400 A photoresist remover composition. The photoresist stripping composition according to claim 4 , wherein the triazole is selected from the group consisting of benzotriazole, carboxybenzotriazole, 1-hydroxybenzotriazole, nitrobenzotriazole, dihydroxypropylbenzotriazole, and mixtures thereof.