JPH0444742B2 - - Google Patents

Description

[Detailed description of the invention]

(Industrial Application Field) The present invention relates to a processing liquid for photoresist. More specifically, the present invention relates to a photoresist processing solution used for developing photosensitive resins that exhibit a difference in solubility in aqueous alkaline solutions after exposure and/or stripping alkali-soluble photosensitive resins. (Prior art) Tetramethylammonium hydroxide or trimethylhydroxyethylammonium hydroxide (also known as (Also called “Colin”)
Strongly alkaline organic substances such as (For example, see Japanese Patent Application Laid-open No. 56-35424.) For finer patterns accompanying the recent increase in the integration of LSI devices, photosensitive resins that have different solubility in alkaline solutions after exposure to light,
For example, a mixture of a novolac resin and/or a hydroxystyrene polymer as the main resin component and a quinonediazide compound or a bisazide compound is used exclusively as a photoresist. Furthermore, recently, in order to prevent contamination due to migration of metal ions into LSI devices, the above-mentioned tetramethylammonium hydroxide and choline-rich aqueous solutions have been used as etching agents or stripping agents instead of inorganic alkaline aqueous solutions containing metals. Concentrated organic aqueous solutions are used. (Problems to be Solved by the Invention) However, when etching the resin film with an etching solution containing a compound such as tetramethylammonium hydroxide and choline, the etching generally occurs, although there are some differences depending on the concentration. The etching was extreme, and there was a tendency for parts of the membrane that should not be etched to be etched. In addition, for example, in the resin film peeling process that follows the etching process in the integrated circuit manufacturing process, in order to prevent phenomena other than resin film peeling from occurring as much as possible, lowering the concentration of the etching solution will increase the time required for the peeling process. This can be prolonged and cause productivity to deteriorate. (Means for Solving the Problems) As a result of extensive prototyping and research conducted by the present inventors over many years, it was discovered that by using a specific quaternary ammonium compound, the above-mentioned conventional compound could be improved. The inventors have discovered that all of the drawbacks of the invention can be overcome, and have completed the present invention. Therefore, the object of the present invention is to solve the following equation () (In the formula, R, R ¹ and R ² are the same or different alkyl groups having 1 to 3 carbon atoms, and n indicates the average number of repeating units and is a positive number of 1 to 3.)
2-hydroxyethyl-(mono- and/or polyoxyethyl)trialkylammonium hydroxide; and water and/or a water-miscible organic solvent; It is an object of the present invention to provide a processing liquid for photoresist, in which the total weight of the photoresist is 0.01% to 50% by weight. The compound of formula () above is a new compound.
The compound of formula () itself has already been filed by the present inventors as Japanese Patent Application No. 59-211742 (see Japanese Patent Application Laid-open No. 61-91156). The preparation of compounds of formula () is not limited to any particular method. For example, when n in the formula is 1, trialkylamine and 2-
(2'-chloroethoxy)ethanol or N,N-dialkylaminoethoxyethanol and an alkyl halide to produce trialkyl-2-hydroxyethoxyethylammonium halide, and the halogen ion of the product is A compound of formula () can be prepared by exchanging with hydroxyl ion by a method. Further, when the compound of formula () is a mixture (n = a positive number of 1 to 3), for example, water is present in a suitable solvent in an amount equal to or more than the amount of water relative to the trialkylamine and the amine. It can be produced by reacting a predetermined amount of ethylene oxide that is double equivalent or more. In formula (), are R, R ¹ and R ² the same?
or different _C1 - _C3 alkyl groups, e.g.
Methyl, ethyl, propyl and isopropyl. Most preferably R, R ¹ and R ² are the same and are methyl groups. When the number of carbon atoms in the alkyl group exceeds 3, the weight of the alkyl group itself in the compound of formula () increases. Therefore, the expression ()
This is not preferable because the molecular weight of the compound increases, and as a result, for example, assuming a solution with a constant content, the alkali equivalent decreases. In the formula (), n means the average number of repeating units and is a positive number from 1 to 3. When n is less than 1 and when n exceeds 3, the compound of formula () is not preferred as a component of the photoresist processing solution of the present invention. As mentioned above, the compound of formula () can be present alone or as a mixture. Therefore, also in the photoresist processing solution of the present invention, the compound of formula () can be used alone or as a mixture. Water-miscible organic solvents used in the photoresist processing solution of the present invention include _C1 - _C4 aliphatic alcohol, acetone, methyl ethyl ketone, N-methylpyrrolidone, dimethyl sulfoxide, N,N-dimethylformamide, N,N-dimethyl selected from the group consisting of acetamide; Preferred organic solvents are _C1 - _C4 aliphatic alcohols, acetone or N-methylpyrrolidone. C1- _C4 aliphatic alcohols include, for example, methanol _, ethanol, isopropyl alcohol and
sec-butanol, etc. The compounds of formula () (both alone or in mixtures) can exist in a stable state in water and/or water-miscible organic solvents. When producing the compound of formula (), for example, if water and/or a C ₁ -C ₄ aliphatic alcohol is used as the reaction solvent, the photoresist processing solution of the present invention can be obtained simultaneously with the completion of the reaction. Alternatively, the reaction solution (e.g.
Another desired solvent (for example, acetone) can also be gradually added while distilling off the _C1 - _C4 alcohol). Water or a water-miscible organic solvent can be used alone as a solvent for forming the treatment liquid, or when using a water-miscible organic solvent, two or more types of solvents can be used in combination, and , water and one or more water-miscible organic solvents may be used in combination. The mixing ratio can be changed arbitrarily. When the photoresist processing solution of the present invention is used as a stripping agent, the preferred organic solvent is acetone or N-methylpyrrolidone. Particular preference is given to using acetone or N-methylpyrrolidone in admixture with water. However, a photoresist processing solution containing a mixture of water and acetone or N-methylpyrrolidone and a compound of formula () can also be satisfactorily used as a developer for positive-working and negative-working photoresists. The concentration of the compound of formula () in the photoresist processing solution of the present invention is within the range of 0.01% to 50% by weight, preferably 0.01% to 30% by weight of the processing solution. Purpose (for example, for development or peeling, etc.), target object (for example,
It can be arbitrarily changed within the above range depending on whether the circuit is a low-integration circuit, a high-integration circuit, an ultra-high-integration circuit, etc.) and/or the photoresist processing conditions (e.g. temperature, processing time, etc.). be able to. Therefore, the exact actual concentration of the photoresist processing solution of the present invention can be easily determined by those skilled in the art by comprehensively considering the above-mentioned factors. The production of the compound of formula () was confirmed by the method disclosed in "Organic Trace Quantitative Analysis" edited by the Organic Trace Analysis Council (published by Nankodo). (Production Examples and Examples) Hereinafter, the present invention will be explained in further detail by giving production examples and examples. Unless otherwise specified, all "parts" in the following description are based on weight. Production Example 1 Production of trimethylhydroxyethylammonium hydroxide A 500 ml pressure vessel was filled with 200 parts of methanol and 72.8 parts of trimethylamine, and heated to 100°C. This reaction mixture was then added to 2-(2'-
125 parts of (chloroethoxy)ethanol was added over 1 hour, and stirring was continued for an additional 4 hours at 100°C to complete the reaction. Thereafter, methanol was distilled off from the reaction mixture under reduced pressure. Acetone 300% to the residue
176 parts (yield: 96%) of the product were isolated by conventional methods. 80 parts of trimethylhydroxyethoxyethylammonium chloride obtained by the above method was dissolved in pure water to make the total amount 1000 parts. This solution was passed through an ion exchange column packed with 700 ml (total exchange capacity: 0.91 eq) of an anion exchange resin (Diaion SA-10A OH type) that had been regenerated in advance at a speed of SV=2. 1170 parts of an aqueous solution containing 6.0% by weight of trimethylhydroxyethoxyethylammonium hydroxide was obtained. Confirmation of trimethylhydroxyethoxyethylammonium hydroxide When an aqueous solution of sodium tetraphenyl boron was added to the eluate flowing out from the ion exchange column, a precipitate was generated. From the above-mentioned document "Organic Trace Quantitative Analysis", it seems that this precipitate was generated according to the following reaction formula (A), and therefore, the presence of ammonium hydroxide in the aqueous solution was presumed. Reaction formula A [(CH ₃ ) ₃ NCH ₂ CH ₂ OCH ₂ CH ₂ OH] OH + [(C ₆ H ₅ ) ₄ B] Na → [(CH ₃ ) ₃ NCH ₂ CH ₂ OCH ₂ CH ₂ OH] [ (C ₆ H ₅ ) ₄ B]+NaOH Next, phosphotungstic acid was added to the eluate from the ion exchange column, and the resulting precipitate was dried and quantified. Thereafter, this precipitate was thermally decomposed at about 800°C, and phosphotungstic acid anhydride was obtained. The reaction proceeded according to the following reaction formulas (B) and (C), and the molecular weight of trimethylhydroxyethoxyethylammonium hydroxide analyzed by this method was 167.2. Reaction formula B 3 [(CH ₃ ) ₃ NCH ₂ CH ₂ OCH ₂ CH ₂ OH] OH+H ₃ PO ₄ H・12WO ₃ → [(CH ₃ ) ₃ NCH ₂ CH ₂ OCH ₂ CH ₂ OH] ₃ PO ₄・12WO ₃ +3H ₂ O Reaction formula C [(CH ₃ ) ₃ NCH ₂ CH ₂ OCH ₂ CH ₂ OH] ₃ PO ₄ H・12WO _{3Heating――} → 800℃HPO ₃・12WO ₃ From the above specific and quantitative analysis results , the production and presence of trimethylhydroxyethoxyethylammonium hydroxide was confirmed. Production example 2 Fill a pressure-resistant container with a capacity of 500 ml with 200 parts of methanol and 94.5 parts of triethylamine, and add 130 parts of methanol and 94.5 parts of triethylamine.
heated to ℃. This reaction mixture was then added to 2-
[2′(2″-chloroethoxy)ethoxy]ethanol
135 parts were added over 1 hour, and stirring was continued for an additional 4 hours at 130°C to complete the reaction. Thereafter, crystallization was performed in the same manner as described in Production Example 1 to obtain 205.0 parts (yield 95%) of triethyl 2-[2'(2''-hydroxyethoxy)ethoxy]ethylammonium chloride. 94.5 parts of ammonium chloride was dissolved in pure water to make a total of 1000 parts, and this solution was added to Production Example 1.
using the same ion exchange resin column used in
The liquid was passed at a speed of SV=2. Triethyl 2-
1440 parts of a solution containing 6.1% by weight of [2′(2″-hydroxyethoxy)ethoxy]ethylammonium hydroxide was obtained. Using this solution, analysis was performed using the method described in Production Example 1 to determine the formation of the above compound. Production Examples 3 to 6 Water and trimethylamine were charged in a pressure container with a capacity of 500 ml in the proportions shown in Table 1 below, and ethylene oxide was added over 2 hours at the specified temperature shown in Table 1. Stirring was continued for another hour at the same temperature.The reaction vessel was opened and water was added to bring the concentration to approx.
It was diluted to 15% by weight to prevent coloring. The results obtained are shown in Table 1 below. Furthermore, each aqueous solution was analyzed by the method described in Production Example 1 to confirm the production and presence of the corresponding quaternary ammonium hydroxide.

[A]

A 4-inch silicon wafer of <100> was heated with H ₂ O ₂ /
Lightly etch with H ₂ SO ₄ aqueous solution, rinse thoroughly with deionized water, and after the electrical conductivity of the deionized water after washing has decreased sufficiently, perform a dehydration bake at 200℃ for more than 1 hour. Ta. The wafer was then cooled while being treated with hexamethyldisilazane (HMDS) vapor under reduced pressure to prepare a clean wafer for use in subsequent experiments. [B] Using a spin coater manufactured by Dainippon Screen, the silicon wafer prepared in step [A] was spin-coated with AZ1370SF positive photoresist (manufactured by Hoechst Co., Ltd.) whose main component is a photosensitive resin consisting of a novolac containing quinonediazide. Then, it was pre-baked at 90°C for 5 minutes on a belt-type hot plate manufactured by Dainippon Screen. The film thickness of the above photoresist after prebaking is approximately 2 μm.
It was hot. A pattern was exposed on this using a Canon proximity contact printer. Broad range ultraviolet light from an ultra-high pressure mercury lamp was used as the exposure source. This ultra-high pressure mercury lamp was fitted with an ND50 filter to control the intensity of the ultraviolet rays. The intensity of the ultraviolet light was 7.6 mW/cm ² at a wavelength of 400 nm. [C] The exposed photosensitive resin of step [B] was processed using the processing solution of the present invention as a developer. As a comparative example,
The same process was carried out using a commercially available choline developer. The development method was an immersion development method with stirring at a solution temperature near room temperature in a clean room. The results obtained are shown in Table 2 below. The exposure energy in the table is based on exposing patterns with different exposure amounts on a single wafer.
Using an optical (n=1.64) film thickness measuring device, a value of 0% residual film rate in the exposed area after a certain development time was used.

[Table] As is clear from the above results, when the processing solution of the present invention containing the compounds of Production Examples 1, 3, and 4 is used as a developer, not only the exposure energy is less for the same development time; The concentration of the compound is about half or less compared to conventionally known choline. Therefore, if the treatment liquid of the present invention is used, waste liquid treatment is extremely easy compared to conventional choline. Example 2 Exposed and developed in Example 1 above
The AZ1370SF photoresist pattern was further printed on a belt-type hot plate made by Dainippon Screen.
The resist layer was post-baked at ℃ for 10 minutes, immersed in the treatment solution of the present invention at room temperature, and peeled off while stirring. The results are shown in Table 3 below.

[Table] As is clear from the results in Table 3, the processing solution of the present invention exhibits a superior photoresist stripping effect compared to the prior art choline even at low concentrations. If choline is used at the same concentration as the treatment solution of the present invention, the treatment time must naturally be increased to obtain an acceptable stripping effect. This means that the processing solution of the present invention has excellent productivity.

Claims (1)

[Claims] 1 (a) General formula () (In the formula, R, R ¹ and R ² are the same or different alkyl groups having 1 to 3 carbon atoms, and n
represents the average number of repeating units and is a positive number from 1 to 3).
or polyoxyethyl) trialkylammonium hydroxide; and (b) water and/or a water-miscible organic solvent. A processing liquid for photoresist, which is 50% by weight. 2. The photoresist processing liquid according to claim 1, which contains a compound in which R, ^R1 , and ^R2 are the same or different alkyl groups having 1 to 3 carbon atoms, and water. 3. The photoresist processing liquid according to claim 2, which contains a compound in which R, R ¹ and R ² are methyl groups, and water. 4. A patent claim in which the water-miscible organic solvent is selected from the group consisting of _C1 - _C4 aliphatic alcohol, acetone, methyl ethyl ketone, N-methylpyrrolidone, dimethyl sulfoxide, N,N-dimethylformamide, N,N-dimethylacetamide The photoresist processing liquid according to item 1. 5. The photoresist processing liquid according to claim 4, wherein the water-miscible organic solvent is acetone or N-methylpyrrolidone. 6 A compound in which R, R ¹ and R ² are methyl groups,
The photoresist processing liquid according to claim 1, which contains water and acetone or N-methylpyrrolidone.