WO2004029723A1

WO2004029723A1 - Photoresist remover composition

Info

Publication number: WO2004029723A1
Application number: PCT/KR2003/002007
Authority: WO
Inventors: Wy-Yong Kim; Suk-Il Yoon; Sam-Young Cho; Soon-Hee Park; Woo-Sik Jun
Original assignee: Dongjin Semichem Co., Ltd.
Priority date: 2002-09-30
Filing date: 2003-09-30
Publication date: 2004-04-08
Also published as: CN1682155A; AU2003265098A1; TW200424760A; KR20040028382A; CN1682155B; TWI228640B; KR100862988B1

Abstract

The present invention relates to a photoresist remover composition, more particularly to a photoresist remover composition comprising (a) 20 to 60 wt % of a water-soluble organic solvent, (b) 10 to 45 wt % of water, (c) 5 to 15 wt % of an alkyl amine or an alcohol amine, (d) 0.1 to 10 wt % of acetic acid, (e) 0.01 to 5 wt % of an oxime compound, (f) 1 to 10 wt % of an organic phenol compound containing two or three hydroxyl groups, and (g) 0.5 to 5 wt % of a triazole compound. The photoresist remover composition of the present invention can easily and quickly remove a resist film hardened during the hard baking, dry etching, ashing, or iron implantation processes, and a resist film transformed by metallic byproducts etched from the bottom metal film during the process in a short time, and can minimize corrosion of the bottom metal wire during the resist removal process, so that it is very effective for a manufacturing process of semiconductor devices, such as integrated circuits, large-scale integrated circuits, and very large-scale integrated circuits.

Description

PHOTORESIST REMOVER COMPOSITION

BACKGROUND OF THE INVENTION (a) Field of the Invention The present invention relates to a photoresist remover composition, more particularly to a photoresist remover composition for removing resist during the manufacture process of semiconductor devices, such as integrated circuits (IC), large-scale integrated circuits (LSI), and very large-scale integrated circuits (VLSI). (b) Description of the Related Art

In the general manufacturing of semiconductor devices, a resist pattern is formed on a conductive layer on top of a semiconductor substrate, and a part of the conductive layer not covered by the pattern is etched to form a conductive layer pattern. This process is repeated dozens of times. After the conductive layer pattern formation, the resist pattern, which has been used as a mask, should be removed from the conductive layer using a resist remover. However, since dry etching is mainly used for the conductive layer pattern formation in the recent very large-scale integrated circuit semiconductor manufacture processes, it has become difficult to remove the resist. Differently from wet etching that uses acidic liquid chemicals, dry etching utilizes a gas-solid reaction of a plasma etching gas and a matter layer, such as a conductive layer. Since the dry etching is easily controllable and offers a sharp pattern, it is dominating in the recent etching processes. However, the dry etching is disadvantageous in the removal of resist, because ions and radicals in the plasma etching gas react with the resist film and rapidly harden the resist film. In particular, in the dry etching of a conductive layer made of tungsten or titanium nitride, the transformed and hardened resist on the side wall is difficult to remove even using a variety of chemicals. The recently proposed resist remover composition comprising a hydroxylamine and aminoethoxyethanol offers relatively good removal effects for most hardened resist films. However, this remover composition significantly corrodes the copper wire metal film which is used in place of the aluminum wire in mass production of over 1-Giga DRAM semiconductors. Also, since a hydroxylamine has a high toxicity, development of an environment-friendly new resist remover is required.

Another recently proposed resist remover composition comprising alkanol amine and diethyleneglycol monoalkyl ether has little odor and toxicity and offers good removal effects for most hardened resist films. However, this remover composition also does not remove a resist film that has been exposed to the plasma etching gas or an ion beam during the dry etching or ion implantation processes very well. Therefore, development of new resist remover that can remove a resist film transformed by the dry etching and ion implantation processes is needed. As described above, it is difficult to remove a resist film that has passed through the ion implantation process using a resist remover. In particular, it is more difficult to remove a resist film that has passed through a high dose ion implantation process to form the source/drain region, in the manufacture of very large-scale integrated circuits. In the ion implantation process, the resist film surface is hardened mainly due to the reaction heat of the high-dose, high-energy ion beam. Also, as ashing proceeds concurrently, the pressure in the resist film increases, and thus the resist film surface may pop (popping) due to the solvent remaining in the film, which causes generation of resist residues. Conventionally, a semiconductor wafer, which is ashing-processed, is treated at a temperature over 200 ^°C. In the process, the solvent remaining in the resist should be vaporized and discharged outside. But, this is impossible for a resist surface passing through a high dose of ion implantation, since a hardened layer exists on the surface. The layer hardened by popping is difficult to remove. And, since the hardened layer is formed by heat, the dopants, which are impurity ions, may be substituted into the resist's molecular structure to cause a crosslinking reaction. Then, the reacted site is oxidized by the O₂ plasma. The oxidized resist turns into residues and particles, which are another contamination source, and reduce the yield of very large-scale integrated circuit production.

Many dry and wet processes to effectively remove the resist hardened layer have been proposed. One of them is a two-step ashing method [Fujimura, Spring Meeting of the Japanese Society of Applied Physics, Presentation 1P-13, p574, 1989]. However, the dry etching processes of this method are complex, require large-scale equipment, and are disadvantageous in production yield.

A resist remover composition comprising an organic amine compound and a variety of organic solvents, which is conventionally used as a resist remover in the wet cleaning process, has been proposed. Particularly, a resist remover composition comprising an organic amine compound, especially monoethanolamine (MEA), as an essential component is widely used.

For instance, a two-component resist remover composition comprising a) an organic amine compound such as MEA and 2-(2-aminoethoxy)ethanol (AEE) and b) a polar solvent such as N,N-dimethylacetamide (DMAc), N,N-dimethylformamide (DMF), N-methylpyrrolidone (NMP), dimethylsulfoxide (DMSO), carbitol acetate, and methoxyacetoxypropane (US Patent No. 4, 617, 251); a two-component resist remover composition comprising a) an organic amine compound such as MEA, monopropanolamine, and methylamylethanol and b) an amide solvent such as N-methylacetamide (MAc), N,N-dimethylacetamide (DMAc), dimethylformamide (DMF),

N,N-diethylacetamide (DEAc), N,N-dipropylacetamide (DPAc), N,N- dimethylpropionamide, N,N-diethylbutylamide, and

N-methyl-N-ethylpropionamide (US Patent No. 4,770,713); a two-component resist remover composition comprising a) an organic amine compound such as alkanolamine (MEA) and b) an aprotonic polar solvent such as 1 ,3-dimethyl-2-imidazolidinone (DMI) and 1 ,3-dimethyl-tetrahydropyrimidinone (Germany Patent Application Publication No. 3,828,513); a resist remover composition comprising a) an alkylenepolyamine introduced by an ethylene oxide of an alkanolamine, such as MEA, diethanolamine (DEA), and triethanolamine (TEA), and an ethylenediamine, b) a sulfone compound such as sulforane, and c) a glycol monoalkyl ether such as diethyleneglycol monoethyl ether and diethyleneglycol monobutyl ether (Japan Patent Application Publication No. Sho 62-49355); a resist remover composition comprising a) a water-soluble amine such as MEA and DEA and b) 1 ,3-dimethyl-2-imidazolidinone (Japan Patent Application Publication No. Sho 63-208043); a positive type resist remover composition comprising a) an amine such as MEA, ethylenediamine, piperidine, and benzylamine, b) a polar solvent such as DMAc, NMP, and DMSO, and c) a surfactant (Japan Patent Application Publication No. Sho 63-231343); a positive type resist remover composition comprising a) a nitrogen-containing organic hydroxy compound such as MEA, b) one or more solvents selected from a group consisting of diethylene glycol monoethyl ether, diethyleneglycol dialkyl ether, γ -butyrolactone, and 1 ,3-dimethyl-2-imidazolinone, and c) DMSO (Japan Patent Application Publication No. Sho 64-42653); a positive type resist remover composition comprising a) an organic amine compound such as MEA, b) an aprotonic polar solvent such as diethylene glycol monoalkyl ether, DMAc, NMP, and DMSO, and c) a phosphate ester surfactant (Japan Patent Application Publication No. Hei 4-124668); a resist remover composition comprising a) 1 ,3-dimethyl-2-imidazolinone (DMI), b) dimethylsulfoxide (DMSO) and c) a water-soluble organic amine compound such as MEA (Japan Patent Application Publication No. Hei 4-350660); and a resist remover composition comprising a) MEA, b) DMSO, and c) catechol (Japan Patent Application Publication No. Hei 5-281753) have been proposed. These resist remover compositions have relatively good safety, workability, and resist removal efficiency.

However, since substrates including silicon wafers are treated at a high temperature of 110 to 140 °C in the recent semiconductor device manufacture processes, the resist tends to be baked. However, the above-mentioned resist removers do not fully remove the baked resist. Resist remover compositions comprising water or a hydroxylamine compound have been proposed to remove the baked resist. For instance, a resist remover composition comprising a) a hydroxylamine, b) an alkanolamine, and c) water (Japan Patent Application Publication No. Hei 4-289866); a resist remover composition a) a hydroxylamine, b) an alkanolamine, c) water, and d) an anticorrosive (Japan Patent Application Publication No. Hei 6-266119); a resist remover composition comprising a) a polar solvent such as GBL, DMF, DMAc, and NMP, b) an amino alcohol such as 2-methylaminoethanol, and c) water (Japan Patent Application Publication No. Hei 7-69618); a remover composition comprising a) an amino alcohol such as MEA, b) water, and c) butyldiglycol (Japan Patent Application Publication No. Hei 8-123043); a resist remover composition comprising a) an alkanolamine and an alkoxyalkyl amine, b) a glycol monoalkyl ether, c) a sugar alcohol, d) a quaternary ammonium hydroxide, and e) water (Japan Patent Application Publication No. Hei 8-262746); a remover composition comprising a) one or more alkanol amines such as MEA and AEE, b) a hydroxylamine, c) a diethyleneglycol monoalkyl ether, d) a sugar (sorbitol), and e) water (Japan Patent Application Publication No. Hei 9-152721); and a resist remover composition comprising a) a hydroxylamine, b) water, c) an amine with a acid dissociation constant (pK_a) ranging from 7.5 to 13, d) a water-soluble organic solvent, and e) an anticorrosive (Japan Patent Application Publication No. Hei 9-96911) have been proposed.

However, these resist remover compositions also do not fully remove resist films that are transformed and hardened during the dry etching, ashing, and ion implantation processes, or resist films that are transformed by metallic byproducts etched from the bottom metal film during the processes. Also, they are environmentally unsafe and do not fully prevent corrosion of the bottom metal wires during the resist removal processes.

SUMMARY OF THE INVENTION

It is an object of the present invention to provide a photoresist remover composition that can easily and quickly remove a resist film that is transformed and hardened during the dry etching, ashing, and ion implantation processes, and a resist film transformed by metallic byproducts etched from the bottom metal film during the processes, and that can minimize corrosion of the bottom metal wire, especially a copper wire, and is environmentally safe.

To attain the object, the present invention provides a photoresist remover composition comprising (a) 20 to 60 wt% of a water-soluble organic solvent, (b) 10 to 45 wt% of water, (c) 5 to 15 wt% of an alkyl amine or an alcohol amine, (d) 0.1 to 10 wt% of acetic acid, (e) 0.01 to 5 wt% of an oxime, (f) 1 to 10 wt% of an organic phenol compound having two or three hydroxyl groups, and (g) 0.5 to 5 wt% of a triazole compound.

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a scanning electron micrograph before applying a photoresist remover composition.

Fig. 2 is a scanning electron micrograph after applying the photoresist remover composition of Example 1 at 65 ^°C.

Fig. 3 is a scanning electron micrograph after applying the photoresist remover composition of Comparative Example 1 at 65 ^°C .

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Hereunder is given a detailed description of the present invention. The present invention relates to a photoresist remover composition comprising an alkyl amine or alcohol amine, acetic acid, and an oxime compound. The photoresist remover composition of the present invention can easily and quickly remove a resist film hardened during the hard baking, dry etching, ashing, or ion implantation process and a resist film transformed by metallic byproducts etched from the bottom metal film during the process, and can minimize corrosion of the bottom metal wire during the resist removal process.

Preferably, the alkyl amine or alcohol amine is one or more compounds selected from a group consisting of ethylamine, dimethylamine, diethylamine, trimethylamine, triethylamine, ethanolamine, diethanolamine, and triethanolamine. Preferably, the alkyl amine or alcohol amine is comprised at 5 to 15 wt%. If the content of the alkyl amine or alcohol amine is below 5 wt%, it is difficult to completely remove the sidewall resist polymer transformed during the dry etching or ashing process. Otherwise, if it exceeds 15 wt%, the bottom metal film made of aluminum or an aluminum alloy is excessively corroded.

Preferably, the acetic acid is comprised at 0.1 to 10 wt%. If the content of the acetic acid is below 0.1 wt%, the polymer removal efficiency decreases. Otherwise, if it exceeds 10 wt%, the bottom metal film is excessively corroded.

Preferably, the oxime compound is one or more compounds selected from a group consisting of acetaldoxime, acetonoxime, and butanonoxime. Preferably, the oxime compound is comprised at 0.01 to 5 wt%. If the content of the oxime compound is below 0.01 wt%, the stripped sidewall photoresist polymer does not dissolve well. Otherwise, if it exceeds 5 wt%, the low-temperature solubility of the photoresist decreases due to the high boiling point of oxime.

Preferably, pure water filtered through an ion exchange resin is used in the present invention. More preferably, ultra pure water with a specific resistance of over 18 MΩ is used. Preferably, the water content is 10 to 45 wt%. If the water content is below 10 wt%, a resist that is severely transformed by metallic byproducts generated during the dry etching and ashing processes is not removed well. Otherwise, if it exceeds 45 wt%, the bottom metal wire may be corroded, and most normal resists, excluding the transformed resist, may not be removed well because the relative contents of the alkyl amine and the water-soluble organic solvent decrease.

Preferably, the organic phenol compound containing two or three hydroxyl groups is a compound represented by the following Chemical Formula 1 :

Chemical Formula 1

Here, m is 2 or 3.

The organic phenol compound containing two or three hydroxyl groups removes the resist film hardened during the dry etching, ashing, and ion implantation processes, and the resist film transformed by metallic byproducts etched from the bottom metal film. The hydroxyl ions resulting from the reaction of hydroxylamine and hydrogen ions of water offer a penetrable space between the resist film and the semiconductor substrate. Also, the hydroxyl groups of the organic phenol compound containing two or three hydroxyl groups prevent corrosion of the bottom metal film photoresist remover composition.

Preferably, the organic phenol compound containing two or three hydroxyl groups is comprised at 1 to 10 wt%. If the content of the organic phenol compound is below 1 wt%, the resist severely transformed by metallic byproducts generated during the dry etching and ion implantation processes is not removed well, and the bottom metal film is severely corroded. Otherwise, if it exceeds 10 wt%, the manufacture price of the composition is high.

Preferably, the water-soluble organic solvent is one or more organic solvents selected from a group consisting of dimethylsulfoxide (DMSO), N-methylpyrrolidone (NMP), dimethylacetamide (DMAc), and dimethylformamide (DMF). Dimethylsulfoxide (DMSO) or dimethylacetamide (DMAc) is more preferable considering the solubility to the resist, prevention of redeposition of the resist, and easy treatment of waste solution due to fast biodegradation. Preferably, the water-soluble organic solvent is comprised at 20 to 60 wt%.

It is possible to effectively prevent corrosion with the organic phenol compound containing two or three hydroxyl groups. However, the partial corrosion at the sidewall or top surface of the bottom metal wire film, or pitting, is not completely resolved. If the organic phenol compound containing two or three hydroxyl groups is used along with a triazole compound, the pitting problem can be prevented.

Preferably, the triazole compound is one or more compounds selected from a group consisting of benzotriazole (BT), tolytriazole (TT), carboxylic benzotriazole (CBT), and a two-component triazole compound comprising benzotriazole (BT) and tolytriazole (TT). Among these, a two-component triazole compound comprising benzotriazole (BT) and tolytriazole (TT) is more preferable. Particularly, if an aromatic phenol compound containing a hydroxyl group is used along with the two-component triazole compound comprising benzotriazole (BT) and tolytriazole, preferably with a mixing ratio of 1 :1 , the side pitting at the resist film sidewall can be prevented more effectively. The triazole compound is comprised at 0.5 to 5 wt%. If its content is below 0.5 wt%, the pitting is not prevented effectively. Otherwise, if it exceeds 5 wt%, the viscosity of the resist remover composition increases, and therefore its use becomes inconvenient.

If the photoresist remover composition of the present invention is used for a semiconductor devices manufacturing process, the resist film can be removed easily in a short time. Especially, a resist film transformed by the tungsten and titanium nitride films can be easily removed. Also, it is environmentally safe and can minimize corrosion of the bottom metal wire during the resist removal process. Particularly, it can minimize corrosion of the copper wire used for mass production of over 1-Giga DRAM very large-scale integrated circuit semiconductors. Hereinafter, the present invention is described more in detail through examples. However the following examples are only for the understanding of the present invention, and the present is not limited by the following examples.

Unless specified otherwise, the contents and mixing ratios in the following examples and comparative examples are based on weight.

EXAMPLES Examples 1 to 5 and Comparative Examples 1 to 2 Photoresist remover compositions of Examples 1 to 5 and Comparative Examples 1 and 2 were prepared with the composition and content given in the following Table 1 :

Table 1

Testing Examples

For each photoresist remover composition prepared in Examples 1 to 5 and Comparative Examples 1 and 2, (1) a resist removal test and (2) a copper corrosion test were carried out. The results are shown in Tables 2 and 3 below. (1) Resist removal test

Preparation of specimen A

On the surface of an 8-inch silicon wafer, on which a 1000 A thick tungsten film and a 700 A thick titanium nitride film are deposited from the bottom to the top, a commonly used positive type resist composition (IS401 , Mitsubishi) was spin-coated so that the final film thickness reached 1.01 μm. Then, the resist film was pre-baked for 90 seconds on a 100 ^°C hot plate. A UV ray was applied after positioning a patterned mask on the resist film. After developing at 21 °C for 60 seconds with a 2.38% tetramethylammonium hydroxide (TMAH) developing solution, the resist patterned specimen was hard-baked for 100 seconds on a 120^°C hot plate. Using the resist pattern formed on the specimen as a mask, a metal wire pattern was formed by etching the tungsten and titanium nitride films not covered by the resist pattern for 35 seconds with a SFe/CI₂ mixture gas using dry etching equipment (M318, Hitachi). Resist removal test

The specimen A was immersed in each resist remover composition at 65 ^°C. The specimen was taken out, washed with ultra pure water, and dried with nitrogen gas. Resist residues on the pattern sidewall and the line pattern surface were observed with a scanning electron microscope (SEM). The resist removal efficiency was evaluated by the following standard. The results are shown in Table 2.

O: Resist residues on the pattern sidewall and the line pattern surface were completely removed. Δ: Over 80% of resist residues on the pattern sidewall and the line pattern surface were removed, but a small amount remains.

X : Most resist residues on the pattern sidewall and the line pattern surface were not removed.

(2) Copper corrosion test Preparation of specimen B

A copper lead frame used in the semiconductor packaging process was prepared.

Copper corrosion test

The specimen B was immersed in each resist remover composition at 65 ^°C. The specimen was taken out, washed with ultra pure water, and dried with nitrogen gas. The specimen surface was observed with a scanning electron microscope. The degree of corrosion was evaluated by the following standard. The results are shown in Table 3. O: No corrosion on the copper surface.

Δ: Partial corrosion on the copper surface. x : Severe corrosion on the entire copper surface.

Table 2: Resist removal efficiency of resist remover composition

As seen in Table 2, while the compositions of Examples 1 to 5 showed superior resist removal efficiency, the conventional compositions of Comparative Examples 1 and 2 showed poor resist removal efficiency.

Table 3: Metal wire corrosion test

Also as seen in Table 3, while the compositions of Examples 1 to 5 showed good results in the metal wire corrosion test, the conventional compositions of Comparative Examples 1 and 2 showed poor corrosion resistance as time went by.

Figs. 1 and 2 are scanning electron micrographs before and after applying the photoresist remover composition of Example 1 , and Fig. 3 is a scanning electron mcrograph after applying the resist remover composition of

Comparative Example 1 (S-4100, Hitachi). The test was carried out at 65 °C for the specimen A.

From Fig. 1 , it can be seen that the resist existed on the sidewall before applying the photoresist.

From Fig. 2, it can be seen that all the resist was removed satisfactorily using the photoresist remover composition of Example 1. From Fig. 3, it can be seen that the resist still remained on the sidewall after the conventional resist remover composition of Comparative Example 1 was used.

As described above, the photoresist remover composition of the present invention can easily remove a resist film hardened during the dry etching, ashing, and ion implantation processes, and a resist film transformed by metallic byproducts etched from the bottom metal film during the process, and can minimize corrosion of the bottom metal wire during the resist removal process. Also, the subsequent rinsing process can proceed with water only without using an organic solvent such as isopropyl alcohol or dimethylsulfoxide.

While the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art will appreciate that a variety of modifications and substitutions can be made thereto without departing from the spirit and scope of the present invention as set forth in the appended claims.

Claims

WHAT IS CLAIMED IS:

1. A photoresist remover composition comprising (a) 20 to 60 wt% of a water-soluble organic solvent, (b) 10 to 45 wt% of water, (c) 5 to 15 wt% of an alkyl amine or an alcohol amine, (d) 0.1 to 10 wt% of acetic acid, (e) 0.01 to 5 wt% of an oxime compound, (f) 1 to 10 wt% of an organic phenol compound containing two or three hydroxyl groups, and (g) 0.5 to 5 wt% of a triazole compound.

2. The photoresist remover composition according to Claim 1, wherein the alkyl amine or alcohol amine is one or more compounds selected from a group consisting of ethylamine, dimethylamine, diethylamine, trimethylamine, triethylamine, ethanolamine, diethanolamine, and triethanolamine.

3. The photoresist remover composition according to Claim 1 , wherein the oxime compound is one or more compounds selected from a group consisting of acetaldoxime, acetonoxime, and butanonoxime.

4. The photoresist remover composition according to Claim 1 , wherein the organic phenol compound containing two or three hydroxyl groups is a phenol compound represented by the following Chemical Formula 1 :

Chemical Formula 1

wherein m is 2 or 3.

5. The photoresist remover composition according to Claim 1 , wherein the triazole compound is one or more compounds selected from a group consisting of benzotriazole (BT), tolytriazole (TT), carboxylic benzotriazole (CBT), and a two-component triazole compound comprising benzotriazole and tolytriazole.

6. The photoresist remover composition according to Claim 1, wherein the water-soluble organic solvent is one or more compounds selected from a group consisting of dimethylsulfoxide (DMSO), N-methylpyrrolidone (NMP), dimethylacetamide (DMAc), and dimethylformamide (DMF).