CN1682155B - Photoresist stripper composition - Google Patents

Abstract

The present invention relates to a photoresist stripper composition, and particularly relates to a photoresist stripper composition comprising 20-60 wt% of water-soluble organic solvent, (b) 10-45 wt% of water, (c) 5-15 wt% of alkylamine or alcohol, (d) 0.1-10 wt% of acetic acid, (e) 0.01-5 wt% of oxime compound, (f) 1-10 wt% of organic phenol compound containing two or three hydroxyl groups, and (g) 0.5-5 wt% of triazole compound. The photoresist stripper composition of the present invention can easily and rapidly remove the resist film hardened in the hard bake, dry etching, ashing or ion implantation process and the resist film modified by the metal byproduct etched from the underlying metal film in the process in a short time. In addition, the composition can minimize corrosion of the underlying metal wiring during the resist removal process. It can be very effectively used in the manufacturing process of semiconductor devices such as integrated circuits, large scale integrated circuits and very large scale integrated circuits.

Description

Photoresist stripper composition

technical field

The present invention relates to a kind of photoresist stripper composition, more particularly relate to a kind of in semiconductor device such as integrated circuit (IC), large-scale integrated circuit (LSI) and very large-scale integrated circuit (VLSI) manufacturing process, be used for A photoresist stripper composition for removing resist.

Background technique

In a typical manufacturing process of a semiconductor device, a resist pattern is formed on a conductive layer on a semiconductor substrate, and then a part of the conductive layer not covered by the pattern is etched to form a pattern of the conductive layer. This process is repeated several times. After the conductive layer is patterned, a resist stripper should be used to remove the resist pattern used as a mask from the conductive layer. However, since in recent VLSI semiconductor manufacturing, a dry etching process is mainly used to form a conductive layer pattern, it becomes difficult to remove the resist.

Unlike wet etching, which uses acidic liquid chemicals, dry etching is performed using plasma etching gas and a gas-solid phase reaction between layers of substances, such as conductive layers. Since dry etching is easy to control and can obtain clear patterns, it has become the mainstream of recent etching processes. However, dry etching is disadvantageous in removing the resist because ions and radicals of the plasma etching gas react with the resist film and harden it rapidly. In particular, in the case of dry etching a conductive layer composed of tungsten and titanium nitride, it is difficult to remove the modified and hardened resist on the sidewall even if various chemicals are used.

A resist stripper composition including hydroxylamine and aminoethoxyethanol has recently been proposed, which can relatively effectively remove most of the hardened resist film. However, this stripper composition severely corrodes copper wiring metal films replacing aluminum wirings in mass production of 1-gigabit DRAM semiconductors. In addition, since hydroxylamine is highly toxic, it is necessary to develop a novel resist stripper that is environmentally friendly.

Recently, a resist stripper composition including alkanolamine and diethylene glycol monoalkyl ether has been proposed, which has less odor and toxicity and has better stripping properties for most hardened resist films. In addition to performance. However, this stripper composition also cannot well remove resist films exposed to plasma etching gas or ion beams in dry etching or ion implantation processes. Therefore, there is a need to develop a new resist stripper capable of removing a resist film modified by a dry etching or ion implantation process.

As described above, it is difficult to remove a resist film subjected to an ion implantation process using a resist stripper. In particular, it is more difficult to remove the resist film that undergoes a high-dose ion implantation process to form source/drain regions in a VLSI manufacturing process. During the ion implantation process, the surface of the resist film hardens mainly due to the heat of reaction of a high-dose, high-energy ion beam. In addition, when ashing proceeds simultaneously, the pressure in the resist film increases, and thus the surface of the resist film may be cracked (popped) due to the remaining solvent in the film, resulting in the formation of resist residues. Typically, ashed semiconductor wafers are processed at temperatures in excess of 200°C. During this process, the solvent remaining inside the resist should be evaporated and drained. However, this is impossible for a resist surface subjected to high-dose ion implantation because a hardened layer is formed on the surface.

The hardened layer after the burst is difficult to remove. Also, since the hardened layer is formed due to heating, dopants, that is, impurity ions may be substituted into the molecular structure of the resist to cause a crosslinking reaction. Then, the reactive sites are oxidized by _O2 plasma. The oxidized resist becomes residue and particles which become another source of contamination and reduce the yield of VLSI.

Many dry and wet processes have been proposed to effectively remove the resist hardened layer. One of them is the two-step ashing method (Fujimura, Spring Meeting of the Japanese Society of Applied Physics, Presentation 1P-13, p574, 1989). However, the dry etching process of this method is complicated, requires large-scale equipment, and has low productivity.

A resist stripper composition including an organic amine compound and various organic solvents has been proposed as a resist stripper used in a conventional wet cleaning process. In particular, resist stripper compositions including an organic amine compound, especially monoethanolamine (MEA) as a main component are widely used.

For example, a two-component system resist stripper composition includes: 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 methoxyacetoxy propane (U.S. Patent 4,617 251); a two-component system resist stripper composition comprising a) an organic amine compound such as MEA, monopropanolamine and methylamyl alcohol and b) an amide solvent such as N- Methylacetamide (MAc), N,N-Dimethylacetamide (DMAc), Dimethylformamide (DMF), N,N-Diethylacetamide (DEAc), N,N-Dipropyl Acetamide (DPAc), N,N-Dimethylpropanamide, N,N-Diethylbutanamide, and N-methyl-N-ethylpropionamide (US Patent 4,770713); a two-component System resist stripper composition comprising a) organic amine compound such as alkanolamine (MEA) and b) aprotic polar solvent such as 1,3-dimethyl-2-imidazolinone (1,3-dimethyl -2-imidazolidinone, DMI) and 1,3-dimethyl-tetrahydropyrimidinone (German Patent Application No. 3,828,513); a resist stripper composition comprising a) an ethoxylated alkanolamine Introduced alkylenepolyamines, and ethylenediamines, of which alkanolamines such as MEA, diethanolamine (DEA) and triethanolamine (TEA), b) sulfone compounds such as sulfolane (sulforane), and c) diol monoalkyl ethers such as diethylene glycol monoethyl ether and diethylene glycol monobutyl ether (Japanese Patent Application No. Sho 62-49355); a resist stripper composition comprising a) water-soluble amines such as MEA and DEA, and b) 1,3-dimethyl-2-imidazolinone (Japanese Patent Application No. Sho 63-208043); a positive resist stripper composition comprising a) amines such as MEA, ethylenediamine , piperidine, and benzylamine, b) polar solvents such as DMAc, NMP, and DMSO, and c) surfactants (Japanese Patent Application No. Zhao 63-231343); a positive resist stripper composition, Including a) nitrogen-containing organic hydroxyl compounds such as MEA, b) one or more selected from diethylene glycol monoethyl ether, diethylene glycol dialkyl ether, γ-butyrolactone and 1,3-dimethyl- A solvent for 2-imidazolinone, and c) DMSO (Japanese Patent Application No. Sho 64-42653); a positive resist stripper composition comprising a) an organic amine compound such as MEA, b) an aprotic electrode solvent such as diethylene glycol monoalkyl ether, DMAc, NMP, and DMSO, and c) a phosphate ester surfactant (Japanese Patent Application No. Hei 4-124668); a resist stripper composition comprising a) 1,3-dimethyl-2-imidazolidinone (DMI), b) dimethylsulfoxide (DMSO), and c) a water-soluble organic amine compound such as MEA (Japanese Patent Application No. Hei 4-350660); and a resist stripper composition comprising a) MEA, b) DMSO, and c) catechol (Japanese Patent Application No. Hei 5-281753). These resist stripper compositions have relatively good safety, workability and resist removal efficiency.

However, since various substrates including silicon wafers are processed at high temperatures of 110-140° C. in recent semiconductor device manufacturing processes, resists tend to be baked. However, the above resist strippers cannot completely remove the baked resist. It has been proposed to remove the baked resist with a resist stripper composition including water or a hydroxylamine compound. For example, resist stripper compositions have been proposed: a resist stripper composition comprising a) hydroxylamine, b) alkanolamine and c) water (Japanese Patent Application No. Hei 4-289866); A resist stripper composition comprising a) hydroxylamine, b) alkanolamine, c) water and d) an anticorrosion agent (Japanese Patent Application No. Hei 6-266119); a resist stripper composition , including a) polar solvents such as GBL, DMF, DMAc, and NMP, b) aminoalcohols such as 2-methylaminoethanol, and c) water (Japanese Patent Application No. Hei 7-69618); a stripper composition , comprising a) aminoalcohol such as MEA, b) water and c) butyldiglycol (Japanese Patent Application No. Hei 8-123043); a resist stripper composition comprising a) alkanolamine and alkanolamine Oxyalkylamine, b) glycol monoalkyl ether, c) sugar alcohol, d) quaternary ammonium hydroxide and e) water (Japanese Patent Application No. Hei 8-262746); a stripper composition, including a) one or more alkanolamines such as MEA and AEE, b) hydroxylamine, c) diethylene glycol monoalkyl ether, d) sugar (sorbitol) and e) water (Japanese Patent Application No. 9-152721); a resist stripper composition comprising a) hydroxylamine, b) water, c) an amine having an acid dissociation constant (pK _a ) of 7.5 to 13, d) a water-soluble organic solvent and e) an anti Etchant (Japanese Patent Application No. Hei 9-96911).

However, these resist stripper compositions also cannot completely remove the resist film modified and hardened in the dry etching, ashing and ion implantation processes, or the metal secondary etched from the underlying metal film in the process. Product Modified Resist Film. Also, they are environmentally hazardous and do not completely prevent corrosion of the bottom metal wiring during the resist removal process.

Contents of the invention

The object of the present invention is to provide a photoresist stripper composition which can easily and quickly remove resist films modified and hardened in dry etching, ashing and ion implantation processes, and In a process, a resist film modified by metal by-products etched from an underlying metal film. In addition, the composition minimizes corrosion to underlying metal wiring, especially copper wiring, and is environmentally safe.

To achieve this purpose, the present invention provides a photoresist stripper composition, which composition includes: (a) 20-60 wt% water-soluble organic solvent, (b) 10-45 wt% water, (c) 5-15wt% alkylamine or alcoholamine, (d) 0.1-10wt% acetic acid, (e) 0.01-5wt% oxime, (f) 1-10wt% organic phenol compound containing two or three hydroxyl groups and (g) 0.5 to 5% by weight of a triazole compound.

Description of drawings

Figure 1 is a scanning electron micrograph of a photoresist stripper composition before application.

Figure 2 is a scanning electron micrograph after using the photoresist stripper composition of Example 1 at 65°C.

3 is a scanning electron micrograph after using the photoresist stripper composition of Comparative Example 1 at 65°C.

Detailed ways

The following is a detailed description of the present invention.

The invention relates to a photoresist stripper composition, which comprises alkylamine or alcoholamine, acetic acid and oxime compound. The photoresist stripper composition of the present invention can easily and quickly remove a resist film hardened in a severe firing, dry etching, ashing or ion implantation process, and in this process, be etched from an underlying metal film The resist film modified by the metal by-products. In addition, the composition minimizes corrosion of underlying metal wiring during the resist removal process.

The alkylamine or alcoholamine is preferably one or more compounds selected from the group consisting of ethylamine, dimethylamine, diethylamine, trimethylamine, triethylamine, ethanolamine, diethanolamine and triethanolamine. The content of alkylamine or alcoholamine is preferably 5 to 15% by weight. If the content of alkylamine or alcoholamine is less than 5 wt%, it will be difficult to completely remove the sidewall resist polymer modified in the dry etching or ashing process. Also, if its content exceeds 15 wt%, it will excessively corrode the bottom metal film made of aluminum or aluminum alloy.

The content of acetic acid is preferably 0.1 to 10 wt%. If the acetic acid content is lower than 0.1 wt%, the polymer removal efficiency will decrease. Also, if its content exceeds 10% by weight, it will excessively corrode the bottom metal film.

The oxime compound is preferably one or more compounds selected from the group consisting of acetaldehyde oxime, acetone oxime and butanone oxime. The content of the oxime compound is preferably 0.01 to 5 wt%. If the content of the oxime compound is less than 0.01 wt%, the stripped sidewall photoresist polymer cannot be well dissolved. In addition, if its content exceeds 5 wt%, the low-temperature solubility of the photoresist will decrease due to the high boiling point of oxime.

Pure water filtered through an ion exchange resin is preferably used in the present invention. It is more preferable to use high-purity water having a resistivity exceeding 18 MΩ. The water content is preferably 10 to 45 wt%. If the water content is less than 10 wt%, the resist heavily modified by metal by-products generated in the dry etching and ashing processes cannot be removed well. In addition, if the content exceeds 45 wt%, the underlying metal wiring may be corroded, and since the relative content of alkylamine and water-soluble organic solvent is reduced, most of the usual resists except modified resists will not be very good. well removed.

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

chemical formula 1

Wherein, m is 2 or 3.

Organic phenol compounds containing two or three hydroxyl groups can remove resist films hardened in dry etching, ashing, and ion implantation processes, and resist films modified by metal by-products etched from the underlying metal film. Hydroxide ions generated by the reaction between hydroxylamine and hydrogen ions of water create a permeable space between the resist film and the semiconductor substrate. In addition, the hydroxyl group of the organic phenol compound containing two or three hydroxyl groups can prevent corrosion of the bottom metal film photoresist stripper composition.

The content of the organic phenol compound containing two or three hydroxyl groups is preferably 1 to 10 wt%. If the content of the organic phenolic compound is less than 1 wt%, the resist which is severely modified by the metal by-products generated in the dry etching and ion implantation process will not be well removed, and the bottom metal film will be severely corroded. Also, if its content exceeds 10% by weight, the cost of the composition will be high.

The water-soluble organic solvent is preferably one or more compounds selected from the group consisting of dimethylsulfoxide (DMSO), N-methylpyrrolidone (NMP), dimethylacetamide (DMAc) or dimethylformamide (DMF). In consideration of the solubility of the resist, the prevention of redeposition of the resist and the easy disposal of the waste liquid due to rapid biodegradation, more preferably dimethyl sulfoxide (DMSO) or dimethylacetamide (DMAc). The content of the water-soluble organic solvent is preferably 20 to 60 wt%.

Corrosion can be effectively prevented from occurring by organic phenol compounds containing two or three hydroxyl groups. However, the problem of partial corrosion of the side wall or upper surface of the bottom metal wiring film, or pitting corrosion has not been completely solved. If an organic phenol compound containing two or three hydroxyl groups is used together with a triazole compound, pitting corrosion problems can be prevented.

The triazole compound is preferably one or more compounds selected from the group consisting of benzotriazole (BT), tolyltriazole (TT), carboxybenzotriazole (CBT) and compounds containing benzotriazole (BT) ) and tolyltriazole (TT) two-component triazole compound. Among them, a two-component triazole compound comprising benzotriazole (BT) and tolyltriazole (TT) is more preferable. In particular, if an aromatic phenol compound containing a hydroxyl group and a two-component triazole compound comprising benzotriazole (BT) and tolyltriazole (TT) having a preferred mixing ratio of 1:1 are used simultaneously, more effective Side pitting of the resist film side wall is prevented. The content of the triazole compound is 0.5-5 wt%. If its content is less than 0.5 wt%, pitting corrosion cannot be effectively prevented from occurring. Also, if its content exceeds 5 wt%, the resist stripper composition will cause inconvenience in use due to increased viscosity.

If the photoresist stripper composition of the present invention is used in a semiconductor device manufacturing process, the resist film can be easily removed in a short time. In particular, resist films modified by tungsten and titanium nitride films can be easily removed. In addition, it is environmentally safe and minimizes corrosion of the bottom metal wiring during the resist removal process. In particular, it is possible to minimize corrosion of copper wiring for mass production of VLSI semiconductors exceeding 1 gigabit DRAM.

The present invention is described in more detail below by way of examples. However, the following examples are only for the understanding of the present invention and are not intended to limit the present invention. The contents and mixing ratios in the following examples and comparative examples are by weight unless otherwise specified.

Example

Embodiment 1-5 and comparative example 1-2

Prepare the photoresist stripper compositions of Examples 1-5 and Comparative Examples 1-2 with the components and contents given in Table 1:

Table 1

Test Example

For each photoresist stripper composition prepared in Examples 1-5 and Comparative Examples 1-2, (1) resist removal test and (2) copper corrosion test were performed. The results are shown in Tables 2 and 3 below.

(1) Resist removal test

Preparation of Sample A

On the surface of an 8-inch silicon wafer, sequentially deposit a thickness of Tungsten film and A titanium nitride film was spin-coated with a generally used positive resist composition (product of Mitsubishi Corporation, product name: IS401) so that the final film thickness reached 1.01 μm. Then, the resist film was prebaked for 90 seconds on a 100° C. hot plate. A mask with a predetermined pattern is placed on the resist film and irradiated with ultraviolet rays. After developing with a 2.38% tetramethylammonium hydroxide (TMAH) developer solution at 21° C. for 60 seconds, the sample of the resist pattern was hard-baked on a 120° C. hot plate for 100 seconds. Using the resist pattern formed on the sample as a mask, using SF ₆ /Cl ₂ mixed gas and dry etching equipment (product of Hitachi, model name: M318), etch the tungsten and nitrogen not covered by the resist pattern TiO film for 35 seconds to form a metal wiring pattern.

Resist Stripping Test

Sample A was immersed in each resist stripper composition at 65°C. The samples were removed, washed with ultrapure water, and dried with nitrogen. The resist residue on the pattern sidewall and the line pattern surface was observed with a scanning electron microscope (SEM). The resist removal efficiency was evaluated by the following criteria. The results are shown in Table 2.

◯: Resist residues on the pattern side walls and the surface of the line pattern were completely removed.

Δ: 80% or more of the resist residue on the pattern side wall and the line pattern surface was removed, but a small amount remained.

X: Most of the resist residues on the pattern side walls and the surface of the line pattern were not removed.

(2) Copper corrosion test

Preparation of Sample B

Copper lead frames used in semiconductor packaging processes are prepared.

Copper Corrosion Test

Sample B was immersed in each resist stripper composition at 65°C. The samples were removed, washed with ultrapure water, and dried with nitrogen. The surface of the sample was then observed with a scanning electron microscope. The degree of corrosion was evaluated by the following criteria. The results are shown in Table 3.

○: No corrosion on the copper surface.

Δ: The copper surface is partially corroded.

×: The entire surface of copper is heavily corroded.

Table 2: Resist Removal Efficiency of Resist Stripper Compositions

As shown in Table 2, the compositions of Examples 1 to 5 exhibited very good resist removal efficiencies, whereas the conventional compositions of Comparative Examples 1 and 2 showed very poor resist removal efficiencies.

Table 3: Metal Wiring Corrosion Tests

Also, as shown in Table 3, in the metal wiring corrosion test, the compositions of Examples 1 to 5 showed good results, while the conventional compositions of Comparative Examples 1 and 2 became poor in corrosion resistance over time.

1 and 2 are scanning electron micrographs before and after using the photoresist stripper composition of Example 1, and FIG. 3 is a scanning electron micrograph after using the photoresist stripper composition of Comparative Example 1 ( A scanning electron microscope from Hitachi, model name S-4100) was used. Testing of Sample A was performed at 65°C.

It can be seen from Figure 1 that there is resist on the sidewall before using photoresist.

It can be seen from FIG. 2 that all the resist was satisfactorily removed after using the photoresist stripper composition of Example 1. FIG.

It can be seen from FIG. 3 that there is still resist on the sidewall after using the common resist stripper composition of Comparative Example 1.

As described above, the photoresist stripper composition of the present invention can easily remove resist films hardened in dry etching, ashing, and ion implantation processes, and etched from underlying metal films in these processes. Metal by-product modified resist film. In addition, the composition minimizes corrosion of underlying metal wiring during the resist removal process. In addition, only water can be used in the subsequent cleaning process instead of organic solvents such as isopropanol or dimethyl sulfoxide.

Although the present invention has been described in detail according to preferred embodiments, those skilled in the art will understand that various modifications and substitutions can be made thereto without departing from the spirit and scope of the invention as claimed in the appended claims.

Claims (4)

1. light carving rubber stripper composition, comprise: (a) water-miscible organic solvent of 20～60wt%, (b) water of 10～45wt%, (c) alkylamine or alkanolamine of 5～15wt%, (d) acetate of 1～10wt%, (e) acetaldoxime of 0.5wt%, the acetaldoxime of 3.5wt%, the diacetylmonoxime of 1wt%, the acetoxime of 0.5wt% or the acetoxime of 3wt%, (f) the organic phenolic compounds that contains two or three hydroxyls represented by following Chemical formula 1 of 1～10wt%, (g) triazole compounds of 0.5～5wt%

Chemical formula 1

Wherein m is 2 or 3.

2. light carving rubber stripper composition according to claim 1, wherein alkylamine or alkanolamine is that one or more are selected from the compound in following group: ethamine, dimethylamine, diethylamine, trimethylamine, triethylamine, monoethanolamine, diethanolamine, triethanolamine.

3. light carving rubber stripper composition according to claim 1, wherein triazole compounds is that one or more are selected from the compound in following group: benzotriazole (BT), azimido-toluene (TT), carboxyl benzotriazole (C BT), comprise the compound of the bi-component triazole of benzotriazole and tolyl-triazole.

4. light carving rubber stripper composition according to claim 1, wherein water miscible organic solvent are that one or more are selected from the compound in following group: dimethyl sulfoxide (DMSO), N-Methyl pyrrolidone (NMP), dimethyl acetamide (DMAc), dimethyl formamide (DMF).

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