KR101375100B1 - Stripper composition for thick negative photoresist - Google Patents

Abstract

The present invention relates to a stripper composition for removing photoresist, wherein the composition according to the present invention comprises 1 to 5% by weight of the compound represented by the formula (1), 70 to 95% by weight of a polar organic solvent, and 0.1 to 5% by weight. It is characterized by containing a hydroxide compound of% and the remaining amount of water. The stripper composition according to the present invention can effectively complete the stripping process in a short time by including a proper amount of the compound represented by the formula (1) without including a corrosion inhibitor in the stripper composition, and has a relatively higher process temperature than other processes. It is possible to minimize the change in composition in the peeling process performed in the. In addition, by not including a corrosion inhibitor, it is possible to prevent electrode damage while preventing post-processing defects such as poor deposition due to adsorption of a water-insoluble corrosion inhibitor.

Description

Stripper composition for negative photoresist of thick film {STRIPPER COMPOSITION FOR THICK NEGATIVE PHOTORESIST}

The present invention relates to a stripper composition that can effectively remove the negative photoresist of a thick film.

Generally, the microcircuits of semiconductor / LED / LCD devices are completed by going through a series of lithography processes. In the lithography process, a metal film or an insulating film is uniformly applied to a substrate, a photoresist is uniformly applied thereon, and then a light is irradiated through a mask having a pattern engraved thereon, and a photoresist having a desired pattern is formed through a developing process. to be. At this time, after the pattern is transferred to the metal film and the insulating film under the photoresist by dry / wet etching, unnecessary photoresist is removed by a peeling process.

 The photoresist is classified into a positive photoresist and a negative photoresist according to a difference in solubility in a developer according to radiation. The positive photoresist develops by increasing the solubility of the exposed portion, and the negative photoresist decreases solubility due to curing of the exposed portion, leaving the pattern after development.

In the case of the positive photoresist, the general wet process is easily removed by a conventional stripping solution, but when hardened and modified by dry etching, ion implantation, or the like, the removal is difficult. The dry etching process is mainly used in the formation of fine patterns because it is easier to control the pattern than the wet etching and obtains the anisotropic pattern. The dry etching process is used for the gas phase-solid reaction between a plasma gas and a material film such as a conductive layer. Since the etching process is performed using the etch process, the ions and radicals of the plasma etching gas chemically react with the photoresist to cure and denature the photoresist film, thereby making it difficult to remove them. In addition, the ion implantation process is a process of diffusing elements such as phosphorous, arsenic, boron, etc. in order to impart conductivity to a specific region of the substrate in the manufacturing process of semiconductor / LED / LCD device, the ions are chemical reaction with the positive photoresist It is also difficult to remove because it causes degeneration.

On the other hand, the negative photoresist is used in a lift-off process and the like, and it is crosslinked by exposure and cannot be removed sufficiently using a general solvent. It is difficult to carry out the process stably because it is necessary.

In general, the photoresist used in the etching process has a film thickness of 2 μm or less, but the photoresist used in an electrode such as a bump electrode forming process or a redistribution line (RDL) has a thickness of 5 μm or more. Since it should be formed to several tens of micrometers, the peeling process for removing the photoresist must be carried out for a long time, thereby reducing the process efficiency.

In addition, since the photoresist is not uniformly removed by the stripping solution, it may cause defects in the semiconductor device, so that the stripping solution composition used during the photoresist removing process should be able to balance the peeling and dissolving action in parallel.

Various photoresist strippers are known. For example, Japanese Patent Application Laid-Open No. 2004-0104033 discloses a photoresist stripper composition composed of a monoethanolamine, a glycol-based compound, a polar solvent, and a corrosion inhibitor. The composition has the property of being able to strip positive photoresist but not of negative photoresist.

Patent application publication 2007-0019897 discloses a stripper composition for negative photoresist composed of hydrazine, a polar organic solvent and a basic compound, but has a characteristic of being difficult to apply the process by including hydrazine as an environmental management substance.

Japanese Patent Application Laid-Open No. 2006-117219 discloses a negative photoresist stripper composition composed of a hydroxide compound, glycols, and dimethyl sulfoxide, wherein the composition can strip a negative photoresist but has a thickness of 120 µm or more. The process efficiency is low because a time of 60 minutes or more is required to remove the photoresist of the thick film.

Patent registration 10-0770217 discloses a composition for removing photoresist of a thick film for forming a bump electrode composed of tetramethylammonium hydroxide (TMAH), an alkanolamine and a polar organic solvent. The composition has a disadvantage in that it is excellent in peeling force on the negative photoresist of the thick film and minimizes damage to the polyimide film, but it is difficult to be applied to a process in which the electrode is not protected by polyimide because the corrosion on the metal electrode is weak.

On the other hand, Patent Application Publication No. 1997-016836 discloses a peeling liquid composition consisting of hydroxylamines, water, amines having an acid dissociation constant (pKa) of 7.5 to 13, a water-soluble organic solvent, and an anticorrosive agent, but it is hydroxyl as an environmental management substance. The inclusion of amines has the disadvantage of being difficult to treat the wastewater, and the use of the anticorrosive agent has a disadvantage in that the composition is complicated and the adsorption of these in the process causes deposition failure in subsequent processes.

Patent application publication 2004-0104033 Patent application publication 2007-0019897 Patent Application Publication 2006-117219 Patent registration 10-0770217 Patent Application Publication No. 1997-016836

Accordingly, the present invention seeks to provide a stripper composition capable of effectively peeling off a negative photoresist of a thick film in a short time.

According to the above object, the present invention, 1 to 5% by weight of the compound represented by the formula (1), 70 to 95% by weight of a polar organic solvent, 0.1 to 5% by weight of the hydroxide compound and the remaining amount of water It provides a photoresist stripping liquid composition comprising.

(1)

(One)

In said formula, n is an integer of 2-8.

The photoresist stripper composition according to the present invention can remove the photoresist of the thick film efficiently even if the short time stripping process is carried out to obtain cost savings due to the shortening of the process time, and is performed at a relatively high process temperature compared to other processes. The change in composition can be minimized. In addition, by not including the corrosion inhibitor, it is possible to prevent electrode damage while preventing post-processing defects such as deposition failure by adsorption of the water-insoluble corrosion inhibitor.

1 is a FE-SEM photograph of the bump electrode surface according to the peeling liquid composition evaluation of Example 1 in the present invention.
Figure 2 is a FE-SEM picture of the surface of the bump electrode according to the peeling performance evaluation in the peeling liquid composition of Comparative Example 1 not according to the present invention.
Figure 3 is a FE-SEM picture of the surface of the bump electrode according to the evaluation of the metal film corrosive with the peeling liquid composition of Comparative Example 1 not according to the present invention.

The present invention provides a stripper composition that can effectively decompose and remove a negative photoresist of a thick film. In the present specification, a thick film means a photoresist film laminated to a thickness exceeding 1 to 2 μm, which is a photoresist thickness used in a general lithography process.

The negative photoresist stripper composition according to the present invention comprises 1 to 5% by weight of a compound represented by the formula (1), 70 to 95% by weight of a polar organic solvent, 0.1 to 5% by weight of a hydroxide compound and the remaining amount It contains water and does not contain corrosion inhibitors.

By including the compound represented by the formula (1) without including the corrosion inhibitor in the peeling liquid composition, it is possible to effectively complete the peeling process in a short time and minimize the compositional change in the peeling process performed at a relatively high process temperature compared to other processes It is possible to prevent damage to the electrode while preventing post-processing defects, such as poor deposition due to adsorption of non-aqueous corrosion inhibitors by not containing corrosion inhibitors.

In general, corrosion inhibitors are a type of surface protector that adheres to the surface of the metal to inhibit corrosion. Corrosion inhibitors adsorb the polar groups on the metal surface and the coating resulting from the arrangement of the nonpolar groups alters the transfer of charges and also prevents the movement of materials involved in corrosion. Therefore, the compound represented by the formula (1) used in the present invention is an amine component composed of a plurality of N (nitrogen atoms) to maximize the peeling performance by the alkali (alkali) degree and the metal surface by a plurality of -N groups Protection can minimize metal electrode damage.

Since the compound represented by the formula (1) used in the present invention is water-soluble, unlike other corrosion inhibitors, post-process defects can be prevented, and examples thereof include diethylenetriamine, triethylenetetraamine, tetraethylenepentaamine, and pentaethylenehexa. Amine, hexaethyleneheptaamine, and the like, and these may be used alone or in combination of two or more thereof. In the formula (1), n is preferably 2 to 8 ethylene amine series. Compounds with n of 1 are ethylenediamine, which is not effective in preventing corrosion due to lack of N (nitrogen atoms) contained in the compound. When n is 9 or more, the molecular weight increases and the ability to penetrate the photoresist decreases, thereby reducing the peeling performance. do.

The content of the compound of formula (1) contained in the stripper according to the present invention is preferably 1 to 5% by weight based on the total weight of the composition. If it is less than 1% by weight, it is not effective in preventing corrosion, and when it is more than 5% by weight, the content of the polar organic solvent is relatively decreased, thereby reducing the peeling performance.

The polar organic solvent contained in the peeling liquid composition according to the present invention can be used without limitation as long as it is a polar organic solvent used in the peeling liquid composition. Specifically, for example

Sulfoxides such as dimethyl sulfoxide; Sulfones such as dimethyl sulfone, diethyl sulfone, bis (2-hydroxyethyl) sulfone and tetramethylene sulfone; Amides such as N, N-dimethylformamide, N-methylformamide, N, N-dimethyl acetamide, N-methylacetamide, N, N-diethyl acetamide; N, N'-dimethyl lactamamide, 2-pyrrolidone, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, N-propyl-2-pyrrolidone, N-hydroxymethyl Lactams such as 2-pyrrolidone and N-hydroxyethyl-2-pyrrolidone; Imidazolidinones, such as 1,3-dimethyl-2-imidazolidinone, 1,3-diethyl-2-imidazolidinone, and 1,3-diisopropyl-2-imidazolidinone; Ethylene glycol, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, ethylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether acetate, diethylene glycol, diethylene glycol monomethyl ether, diethylene glycol mono Polyhydric alcohols, such as ethyl ether and diethylene glycol monobutyl ether, and its derivative (s) are mentioned.

These may be used independently, or may combine 2 or more types. Among these, dimethyl sulfoxide, N, N-dimethylformamide, N, N-dimethylacetamide, N, N'-diethylacetamide, N-methylformamide, N, N'-dimethyllactamamide, 1, At least one selected from 3-dimethyl-2-imidazolidinone, diethylene glycol monomethyl ether, ethylene glycol monoethyl ether, N-methyl pyrrolidone, N-ethyl pyrrolidone and 2-pyrrolidone It is more preferable to use since it is excellent in peelability.

It is preferable that the content of the polar organic solvent contained in the peeling liquid composition which concerns on this invention is 70 to 95 weight%, More preferably, it is 80 to 95 weight%. If the content is less than 70% by weight, there is a problem that the solubility of the photoresist is inferior, so that the resist is not removed cleanly, and when the content is more than 95% by weight, the content of other components is insufficient. The peeling performance is lowered, there is a problem that the corrosion phenomenon may appear.

The hydroxide compound contained in the stripper according to the present invention is added to further improve the stripping performance of the negative photoresist, and tetraalkylammonium hydroxide is preferred. At this time, the alkyl may be selected from an alkyl group of C ₁ ~ C ₅ .

The content of the hydroxide compound is preferably 0.1 to 5% by weight, more preferably 1 to 4% by weight based on the total composition of the stripping solution. If the content is less than 0.1% by weight, there is a problem that the peeling performance is lowered, if the content exceeds 5% by weight there is a risk of causing corrosion to the lower metal film.

Although the water contained in the composition of the present invention is not particularly limited, deionized water may be used. Preferably, deionized water having a specific resistance of 18 ㏁ / cm or more that shows the degree of removal of ions in water is used.

Hereinafter, the present invention will be described in detail by way of examples. However, the following examples are illustrative of the present invention, and the present invention is not limited to the following examples.

< Example  1 to 13 lessons Comparative Example  1 to 7>

A negative photoresist stripper composition was prepared by combining the compound of formula (1), a polar organic solvent, a hydroxide compound and water as shown in Table 1.

Compound of Formula (1)
[weight%] Polar organic solvent
[weight%] Hydroxide-based compound [% by weight] water
[weight%] Example 1 DETA One DMSO 89 TMAH 2 8 Example 2 TETA 3 DMSO 87 TMAH 2 8 Example 3 TEPA 3 DMSO 87 TMAH 2 8 Example 4 TEPA One DMSO 89 TMAH 2 8 Example 5 TEPA 5 DMSO 85 TMAH 2 8 Example 6 TEPA 3 DMSO 92 TMAH One 4 Example 7 TEPA 3 NMP 87 TMAH 2 8 Example 8 TEPA 3 PRD 87 TMAH 2 8 Example 9 TEPA 3 NEP 87 TMAH 2 8 Example 10 TEPA 3 DMAc 87 TMAH 2 8 Example 11 TEPA 3 DMF 87 TMAH 2 8 Example 12 TEPA 3 DMSO 87 TEAH 3.5 6.5 Example 13 TEPA 3 DMSO 87 TBAH 4 6 Comparative Example 1 - - DMSO 90 TMAH 2 8 Comparative Example 2 EDA 3 DMSO 87 TMAH 2 8 Comparative Example 3 PEHA 5 DMSO 87 - - 8 Comparative Example 4 DETA 0.1 DMSO 89.9 TMAH 2 8 Comparative Example 5 DETA 10 DMSO 80 TMAH 2 8 Comparative Example 6 TEPA 0.1 DMSO 89.9 TMAH 2 8 Comparative Example 7 TEPA 10 DMSO 80 TMAH 2 8
Formula (1) Compound-EDA: ethylenediamine, DETA: diethylenetriamine, TETA: triethylenetetraamine, TEPA: tetraethylenepentaamine, PEHA: pentaethylenehexaamine
Polar organic solvents-DMSO: dimethylsulfoxide, NMP: N-methylpyrrolidone, PRD: 2-pyrrolidone, NEP: N-ethyl pyrrolidone, DMAc: N, N-dimethylacetamide, DMF: N , N-dimethylformamide
● Hydroxide compound-TMAH: Tetramethylammonium hydroxide, TEAH: Tetraethylammonium hydroxide, TBAH: Tetrabutylammonium hydroxide

<Photoresist peeling performance evaluation>

Photoresist stripping performance of the photoresist stripper composition prepared as shown in Table 1 was evaluated.

In order to evaluate the photoresist peeling performance of the composition, bump electrodes of photoresist and tin material were formed on a copper plated wafer with a thickness of about 50 to 60 μm. Specifically, a photoresist film was formed to a thickness of about 50 to 60 μm on a wafer on which an UBM (Under Bump Metallurgy) layer was formed of copper. After the pattern was formed on the photoresist carried out by the exposure process, a bump electrode of tin material was formed by an electroplating method through a developing process.

Subsequently, an evaluation specimen was prepared by cutting a wafer composed of a photoresist and a bump electrode to a size of 3 cm x 3 cm. The specimens were immersed at 60 ° C. for 3 minutes in each of the stripper compositions prepared as shown in Table 1 to remove the photoresist film. The specimen from which the photoresist film was removed was washed with ultrapure water for about 1 minute and then dried with nitrogen. The dried specimens were checked for photoresist removal by FE-SEM (see FIGS. 1 and 2). 1 is a FE-SEM picture of the bump electrode surface according to the peeling liquid composition evaluation of Example 1, Figure 2 is a FE-SEM picture of the bump electrode surface according to the peeling performance evaluation with the peeling liquid composition of Comparative Example 1.

The experimental conditions are intended to provide a wider difference in the degree of peeling by providing a flat condition as compared to the peeling process of the conventional bump electrode photoresist is 10 minutes or more. The results are shown in Table 2.

◎: 100% photoresist removed, no residue

○: 80 80% or more of photoresist removed, almost no residue

△: 50% or more of photoresist removed

×: Less than 50% of photoresist removed, leaving a large amount of photoresist

<Metal Film Corrosion Evaluation>

Corrosion property of the bump electrode metal was evaluated for the photoresist stripper composition prepared as shown in Table 1 above.

In order to evaluate the corrosiveness of the bump electrode metal of the composition, a bump electrode of photoresist and tin material was formed on a copper plated wafer at a thickness of about 50 to 60 μm. Subsequently, an evaluation specimen was prepared by cutting a wafer composed of a photoresist and a bump electrode to a size of 3 × 3 cm.

The specimens were immersed at 60 ° C. for 30 minutes in each of the stripper compositions prepared as shown in Table 1, washed with ultrapure water for 1 minute, and dried using nitrogen. The dried specimens were FE-SEM to determine the degree of corrosion of the surface of the bump electrode metal. Figure 3 is a FE-SEM picture of the surface of the bump electrode according to the evaluation of the metal film corrosive with the peeling liquid composition of Comparative Example 1 not according to the present invention.

The experimental condition is to provide a severe corrosion condition compared to the conventional peeling process of the bump electrode photoresist within 10 minutes to see a large difference in the degree of corrosion. The results are shown in Table 2.

◎: No corrosion of copper and tin

: Slight metal corrosion of copper and tin is observed

Δ: Partial metal corrosion of copper and tin is observed

×: Metal corrosion of copper and tin was observed as a whole

Photoresist Peeling Degree Metal film corrosion degree Example 1 ◎ ○ Example 2 ◎ ◎ Example 3 ◎ ◎ Example 4 ◎ ○ Example 5 ◎ ◎ Example 6 ○ ◎ Example 7 ◎ ◎ Example 8 ◎ ◎ Example 9 ◎ ◎ Example 10 ◎ ◎ Example 11 ◎ ◎ Example 12 ○ ◎ Example 13 ○ ◎ Comparative Example 1 △ × Comparative Example 2 ◎ △ Comparative Example 3 × ◎ Comparative Example 4 △ × Comparative Example 5 △ ◎ Comparative Example 6 △ △ Comparative Example 7 △ ◎

As can be seen from the above results, the photoresist stripper composition according to the present invention does not contain a corrosion inhibitor and contains an appropriate amount of the compound represented by the formula (1), so that the photoresist of the thick film can be efficiently removed even if the stripping process is performed for a short time. In this way, the cost can be reduced by reducing the process time.

Claims (5)

A photoresist stripper composition comprising 1 to 5% by weight of a compound represented by formula (1), 70 to 95% by weight of a polar organic solvent, 0.1 to 5% by weight of a hydroxide-based compound, and a balance of water:

(One)
N is an integer of 2-8. The compound represented by the formula (1) is selected from diethylenetriamine, triethylenetetraamine, tetraethylenepentaamine, pentaethylenehexaamine, hexaethyleneheptaamine and mixtures thereof. Photoresist stripping liquid composition. The polar organic solvent of claim 1, wherein the polar organic solvent is dimethyl sulfoxide, N, N-dimethyl formamide, N, N-dimethyl acetamide, N, N'-diethyl acetamide, N-methyl formamide, N, N '-Dimethyl lactamamide, 1,3-dimethyl-2-imidazolidinone, diethylene glycol monomethyl ether, ethylene glycol monoethyl ether, N-methyl pyrrolidone N-ethyl pyrrolidone, 2-pyrrolidone And a mixture thereof. The photoresist stripper composition of claim 1, wherein the hydroxide-based compound is tetraalkylammonium hydroxide, wherein alkyl is C ₁ -C ₅ alkyl. The photoresist stripper composition according to claim 1, for removing a negative photoresist of a thick film.

Images