JPH0720639A - How to form a pattern - Google Patents

Abstract

PURPOSE:To form a satisfactory pattern not causing sag, leaving no thin film at the bottoms of bias holes after development and free from scum due to rinse shock and damage at the exposed part by using a specified liq. rinse. CONSTITUTION:When a prescribed pattern is formed from a photosensitive compsn. contg. a photocrosslinkable polymer having repeating units represented by formula I, a liq. rinse contg. a compd. represented by formula II and having a liq. state at ordinary temp. is used. In the formula I, X is a (2+n)-valent carbocyclic or heterocyclic group, Y is a (2+m)-valent carbocyclic or heterocyclic group, Z is -C(=O)-NH, etc., R is a group having a C=C double bond, W is a group capable of forming a ring by a reaction with a carbonyl group represented by-COR when heat-treated, (n) is 1 or 2 and (m) is 0, 1 or 2. In the formula II, R1 is 1-6C alkyl and R2 is H or 1-6C alkyl.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for forming a predetermined pattern from a photocrosslinking polymerization composition used as a polyimide precursor when forming an interlayer insulating film in the semiconductor industry.

[0002]

2. Description of the Related Art In recent years, in the semiconductor industry, a resin having a heterocycle such as a polyimide resin, which has high heat resistance and is excellent in forming a step as compared with an inorganic substance, is used as an insulating film or a passivation film in a solid element, or in an integrated circuit or a multilayer. Prints have come to be used as interlayer insulation films for wiring boards. When forming an interlayer insulating film, it is necessary to provide via holes for conducting the upper and lower layers, and as a method therefor, a pattern forming method using a photosensitive polyimide having excellent processability has been proposed. There is.

Among these materials used for pattern formation, a photocrosslinkable polymer composition having a repeating unit represented by the following formula [I] is excellent in forming a thick film and has a film slippage in an exposed portion during development. It has excellent characteristics such as no

[0004]

[Chemical 3]

The pattern forming method using the composition is carried out, for example, in the following order of steps. 1 Application: The precursor composition varnish is applied on a predetermined substrate. 2 Drying: The solvent is evaporated to form a coating film of the precursor composition. 3 Exposure: Exposure is performed using a predetermined photomask. 4 Development: The unexposed area is dissolved and removed with a soluble developing solution, and rinsed with a rinse solution.

5 Thermosetting: By heating, it is converted into a polyimide resin to obtain a predetermined pattern. As a conventional developing / rinsing solution in a series of steps, a developing solution of a good solvent alone of the precursor or a mixture of a good solvent and a poor solvent and a rinse solution of a poor solvent of the precursor alone or a mixture of a poor solvent are used. . For example, a developing solution of dimethylacetamide alone, a developing solution of a mixture of dimethylformamide and xylene in a ratio of 1: 1 (volume ratio), isopropyl alcohol alone or a mixture of isopropyl alcohol and xylene of 1:
A 1 (volume ratio) mixed rinse solution is used.

[0007]

When a pattern is formed by the above method, the pattern may be dripping or a thin film may remain in the lower portion of the via hole after development depending on the combination and balance of the developing solution and the rinsing solution, and a poor solvent may be used. A rinse shock may be caused by the rinse liquid, and the residue may adhere to the entire surface or a part of the substrate or the surface may be roughened.

[0008]

Means for Solving the Problems As a result of intensive studies for solving the problems of the prior art as described above, the present inventors have found that by using the rinse liquid described in detail below,
It was possible to obtain a good pattern in which the pattern did not drip, a thin film did not remain at the bottom of the via hole after development, scum due to the rinse shock did not occur, and the exposed portion was not damaged.
That is, the present invention provides a method of forming a predetermined pattern from a photosensitive composition containing a photocrosslinkable polymer having a repeating unit represented by the following formula [I], which is represented by the following formula [II] in an amount of 10% by volume or more. The pattern forming method is characterized in that a rinse liquid containing a compound that is liquid at room temperature is used.

[0009]

[Chemical 4]

[0010]

[Chemical 5]

The X of the formula [I] used in the present invention has a chemical structure excluding the carboxyl group of the aromatic tetracarboxylic acid, and examples thereof include acids such as pyromellitic acid anhydride and benzophenone tetracarboxylic acid anhydride. There is an anhydride. Y represents a chemical structure excluding the amino group of aromatic diamine, and examples thereof include diamines such as 4,4′-diaminodiphenyl ether and 4,4′-diaminodiphenyl sulfone. That is, the polymer of the formula [I] includes, but is not limited to, a polyimide precursor having a photosensitive group in a side chain of a repeating unit formed by polycondensation of an acid anhydride and a diamine.

The photosensitive group introduced into the precursor is a group having a carbon-carbon double bond which is dimerizable or polymerizable by light, such as vinyl group, allyl group, acryl group, methacryl group, cinnamyl group, maleimide. A group having a group is preferable, but not limited thereto. The bonding form of the photosensitive group generally includes covalent bond such as ester bond and amide bond and ionic bond.

Examples of the photosensitive compound mixed for the purpose of improving the photosensitivity of the photocrosslinkable polymer having the repeating unit represented by the formula [I] include, but are not limited to, the following examples. For example, benzophenone, 4,4'-
Benzophenones such as bis (dimethylamino) benzophenone, benzoin ether or anthraquinone, thioxanthone derivatives, bisazides such as 2,6-bis- (4'-diethylaminobenzal) -cyclohexanone, 1-phenyl-5-mercaptotetrazole, etc. Mercapto compounds, oximes such as 1-phenyl-1,2-propanedione-2- (O-ethoxycarbonyl) -oxime, and imidazoles such as 2,4,5-triphenylimidazole dimer. The following are preferable examples of the photosensitive monomer, but the photosensitive monomer is not limited thereto. For example, (meth) acrylates such as trimethylolpropane triacrylate, trimethylolpropane trimethacrylate, and dimethylaminoethylmethacrylate, mercapto compounds such as thioglycol, maleimides such as phenylsulfonylmaleimide, and isocyanates such as ethylmethacrylate methacrylate. is there.

It is preferable to add 0.1 to 50 parts by weight of these additives to 100 parts by weight of the photocrosslinkable polymer. As the solvent, N, N′-dimethylformamide,
N, N′-dimethylacetamide, γ-butyrolactone, N-methylpyrrolidone and the like are preferable, but not limited thereto. As the compound represented by the formula [II], R ₁ is preferably an alkyl group having 3 carbon atoms, but is not limited thereto. When a mixed solvent is used, if the residue does not remain after rinsing, the mixing amount is not limited and can be arbitrarily selected.

The coating method on the substrate is typically performed by a spinner, a roll coater or the like, and examples of the substrate include, but are not limited to, silicon wafers, ceramics and copper plates. As a drying method, a hot plate, a circulation type oven or the like can be cited as a good example, and a drying temperature is 50 to 140 ° C., more preferably 60 to 100.
℃ is good drying time depends on the thickness and drying method,
A hot plate is preferably, but not limited to, about 1 to 5 minutes.

As an exposure method, it is preferable to irradiate ultraviolet rays through a photomask with an exposure device used in a usual photoresist process. The exposure time varies depending on the type of the photocrosslinking polymer, the type of additives and the light intensity of the exposing machine, but generally, the optimum time may be selected from 0.1 second to 10 minutes. There is no problem as long as the treatment such as heat treatment after the exposure is carried out according to the performance of the varnish to be used, and the treatment is not particularly limited.

Examples of the developing solution include a good solvent for the polymer alone, and a mixed solvent in which a good solvent and a poor solvent are combined. Examples of the good solvent include N, N′-dimethylformamide, N, N′dimethylacetamide, cyclopentanone, N-methylpyrrolidone, γ-butyrolactone, and the like, as long as they dissolve the polymer,
It is not limited to these. Further, these may be a mixed system of two or more kinds. As the poor solvent, toluene, xylene, acetone, ethylbenzene, methyl cellosolve, ethyl acetate, isopropylbenzene, isopropyl alcohol,
Examples thereof include, but are not limited to, isobutyl alcohol and water. Further, there is no restriction on the amount ratio of these as long as the polymer can be dissolved therein.

The developed pattern image of the polymer composition is immediately rinsed with a rinse to remove the developer.
As the rinse liquid, the compound represented by the formula [II] is used.
A solvent containing at least 100 volumes but not less than 50 volumes, more preferably at least 100 volumes is used. When mixing, it is preferable to use a poor solvent for the polymer,
Examples include, but are not limited to, toluene, xylene, acetone, ethylbenzene, methyl cellosolve, ethyl acetate, isopropylbenzene, isopropyl alcohol, isobutyl alcohol, water and the like.

As the developing method, spray development, immersion development and ultrasonic development are mentioned as favorable examples, and the highest resolution is obtained by spray development. Also, when this method is selected, the ignition point of the developer and rinse solution,
Higher flash points are preferred. The conversion of the obtained polyimide precursor pattern into polyimide is performed by thermosetting at 200 ° C. to 500 ° C. for 5 minutes to 3 hours. Examples of the method include, but are not limited to, a circulation oven, a vertical thermosetting oven, and a hot blade.

[0020]

EXAMPLES Next, the present invention and its effects will be described by way of examples.

[0021]

Reference Example 1 27.0 g of pyromellitic anhydride and 27.0 g of 2-hydroxyethyl methacrylate were dissolved in 100 ml of γ-butyrolactone, and the mixture was stirred at room temperature for 15 hours. Next, 23.8 g of thionyl chloride was added dropwise with stirring. Further, 16 g of 4,4′-diaminodiphenyl ether slurried with 50 ml of γ-butyrolactone was added dropwise under ice cooling, stirred for 2 hours and then added dropwise to 10 l of ion-exchanged water while stirring, and the precipitate was filtered,
It was washed and air-dried to obtain a pale yellow powder. 10 g of this powder, 1.5 g of trimethylolpropane triacrylate, 0.6 g of Michler's ketone and 15 ml of n-methylpyrrolidone
In addition, a homogeneous solution was obtained. This solution is hereinafter referred to as S-1.

[0022]

[Reference Example 2] 110 g of diaminodiphenyl ether was added to N
-Dissolved in 278 g of methylpyrrolidone to give an amine solution. 120 g of pyromellitic acid anhydride was dispersed in 308 g of dimethylacetamide, and then 184 g of N-methylpyrrolidone was added and dissolved to obtain an acid solution. An acid solution was added to the amine solution at 60 ° C., and the mixture was reacted for 3 hours to obtain a uniform solution. 50 g of this solution, 1.15 g of Michler's ketone
Was dissolved in 30 g of dimethylacetamide, and a solution of 0.2 g of diethylaminoethyl methacrylate in 10 g of dimethylacetamide was mixed and filtered. This solution is hereinafter referred to as S-2.

[0023]

[Example 1] S using a spinner on a silicon wafer
-1 was applied and dried in a circulating oven at 70 ° C. for about 2 hours. The film thickness was 20 μm. 5-100 on this coating
A photomask on which a through-hole test pattern of μm square (in increments of 5 μm) is printed is brought into close contact, and M manufactured by Mikasa Co., Ltd.
It exposed for 30 seconds using the A-10 exposure machine. Next, spray development was carried out using a D spin 636 developing machine manufactured by Dainippon Screen Mfg. Co., Ltd. Development conditions are NMP / isopropyl alcohol / water (70/25/5, volume ratio)
30 seconds development with 2-acetoxy, 1-methoxypropane / isopropyl alcohol (90/10)
Rinsing was performed for 15 seconds. The resolution (minimum via hole diameter) of the obtained pattern was 20 μm, and a good pattern without any residue was obtained.

[0024]

Embodiments 2 and 3 Embodiments 2 and 3 are the results of experiments conducted by using the same equipment as in Embodiment 1 but changing the developing conditions. The experimental conditions are shown in Table-1, the developing / rinsing solution composition is shown in Table-2,
The experimental results are shown in Table-3.

[0025]

[Comparative Example 1] S using a spinner on a silicon wafer
-1 was applied and dried in a circulating oven at 70 ° C. for about 2 hours. The film thickness was 20 μm. 5-100 on this coating
A photomask on which a through-hole test pattern of μm square (in increments of 5 μm) is printed is brought into close contact, and M manufactured by Mikasa Co., Ltd.
It exposed for 30 seconds using the A-10 exposure machine. Next, spray development was carried out using a D spin 636 developing machine manufactured by Dainippon Screen Mfg. Co., Ltd. Development conditions are NMP / isopropyl alcohol / water (70/25/5, volume ratio)
Development was carried out for 30 seconds, followed by rinsing with methyl cellosolve for 15 seconds. The obtained pattern had a resolution (minimum via hole diameter) of 25 μm, and a small amount of residue was confirmed.

Examples 2 and 3 and Comparative Examples 2 and 3 are Example 1
And, it is the result of an experiment in which the developing conditions were changed using the same equipment as in Comparative Example 1. The experimental conditions are shown in Table-1.
Table 2 shows the composition of the rinse solution and Table 3 shows the experimental results.

[0027]

Comparative Examples 2 and 3 Comparative Examples 2 and 3 are the results of experiments using the same equipment as in Comparative Example 1 but changing the developing conditions. The experimental conditions are shown in Table-1, the developing / rinsing solution composition is shown in Table-2,
The experimental results are shown in Table-3.

[0028]

[Example 4] S using a spinner on a silicon wafer
-2 was applied and dried in a circulating oven at 60 ° C. for about 2.5 hours. The film thickness was 20 μm. 5 to 1 on this coating
A photomask on which a through-hole test pattern of 00 μm square (in 5 μm increments) is printed is brought into close contact with Mikasa Co., Ltd.
It exposed for 60 seconds using the MA-10 exposure machine made from. Next, the developing solution was placed in a beaker to carry out immersion development. NMP /
Propylene glycol monoethyl ether / water (70 /
(25/5, volume ratio) for 70 seconds, followed by 2-acetoxy, 1-ethoxyethane rinse solution for 1 second.
It was immersed for 5 seconds and air dried. The resolution (minimum via hole diameter) of the obtained pattern was 20 μm, and a good pattern without any residue was obtained.

[0029]

[Comparative Example 4] S using a spinner on a silicon wafer
-2 was applied and dried in a circulating oven at 60 ° C. for about 2.5 hours. The film thickness was 20 μm. 5 to 1 on this coating
A photomask on which a through-hole test pattern of 00 μm square (in 5 μm increments) is printed is brought into close contact with Mikasa Co., Ltd.
It was exposed for 40 seconds using a MA-10 exposure machine manufactured by Mitsui Chemicals. Next, the developing solution was placed in a beaker to carry out immersion development. NMP /
Immersion development was carried out for 60 seconds in a developing solution of isopropyl alcohol / water (70/25/5, volume ratio), followed by immersion for 15 seconds in a rinse solution of isopropyl alcohol and air drying. The resolution of the obtained pattern (minimum via hole diameter) is 25.
μm, and a small amount of residue was confirmed. Was given.

[0030]

[Table 1]

[0031]

[Table 2]

[0032]

[Table 3]

[0033]

According to the method of the present invention, when a pattern is formed using a photocrosslinking polymer composition, it is possible to provide a pattern having no residue and surface damage, which are problems in the past, and having an extremely high resolution. Became.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Office reference number FI Technical display location G03F 7/038 504 H01L 21/027 H05K 3/06 9443-4E

Claims (1)

[Claims] 1. A method of forming a predetermined pattern from a photosensitive composition containing a photocrosslinkable polymer having a repeating unit represented by the following formula [I], wherein 10% by volume or more of the following formula [II] is used. A pattern forming method comprising using a rinse liquid containing a compound that is liquid at room temperature. [Chemical 1] [Chemical 2]