JPS63173042A - Positive type photoresist composition - Google Patents

Abstract

PURPOSE:To obtain various characteristics such as superior line width controllability, sensitivity, resolving power and heat resistance even on a substrate having high reflectance by adding a specified light absorbing material to a positive type photoresist compsn. contg. an alkali-soluble resin and a compd. having a 1,2-naphthoquinonediazido group. CONSTITUTION:A light absorbing material represented by formula I is added to a positive type photoresist compsn. contg. an alkali-soluble resin and a compd. having a 1,2-naphthoquinonediazido group by 0.1-10wt.% of the total amt. of the solid substances. In the formula I, R<1> is 1-6C alkyl group, R<2> is optionally substd. alkyl, optionally substd. aryl group or the like and Ar is optionally substd. aryl group. The light absorbing material enough to eliminate the influence of reflection from a substrate can be dissolved and the lowering of the sensitivity can be suppressed to such a degree that no trouble is caused in practical use.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention generally relates to a positive photoresist composition sensitive to Kli radiation, and more specifically to an alkali-soluble resin and/or a compound containing a -1-naphthoquinone diazide group. The present invention relates to an improvement in a positive photoresist composition comprising:

(Conventional technology) The density of integrated circuits has been increasing at an accelerating pace year by year, and we are now in the era of so-called ultra-LSIs with a density of 100,000 or more, and the era of designs based on the λμm rule and even submicron rules. Along with this, the requirements for photolithography technology are becoming stricter year by year.In this photolithography technology, most of the resists conventionally used are made of cyclized polyisoprene rubber with a bisazide compound as a photocrosslinking agent. It is difficult to obtain additions.

the above! A positive type photoresist can meet the demand for l+. Positive-working photoresist compositions include both an alkali-soluble resin and a photosensitive material, typically a compound containing a substituted naphthoquinone diazide group.

During irradiation, toquinone diazide absorbs ultraviolet rays as shown in the formula below, produces ketene through carbene, reacts with water present in the system, forms indene carboxylic acid, and dissolves in the alkaline water of the developer. Applying phenomena.

In this way, positive-type photoresists use an alkaline aqueous solution as a developer, so unlike the case of negative-type photoresists, the resist does not swell, and therefore it is possible to increase the dissolving power.

Compared with negative-type resists, positive-type photoresists have generally appeared as resists that are characterized by non-swelling and high resolution, and have been widely used in the manufacture of VLSIs.

(Problem to be solved by the invention) However, although this is a positive photoresist that boasts high resolution, when patterning is attempted on a substrate with high reflectance, the image is affected by the light reflected from the substrate. It became clear that control of blurring (halation) and line width became extremely difficult. This phenomenon becomes more pronounced when the substrate has a step difference, and it has been desired to develop a resist that overcomes this problem.

In order to solve these problems, it is known to add a light-absorbing material. /-37! ≦
It is disclosed in the λ publication.

However, it is extremely difficult to select a light-absorbing feather that does not affect the other properties of the resist at all or only to a practical extent.

For example, if a highly lipophilic light-absorbing side bead is added, it will easily dissolve in the resist solution, but when it is actually used, the lipophilicity of the entire resist film will increase. As a result, the solubility in the developer decreases, resulting in a decrease in sensitivity and a thick edge that generates scum. Moreover, since it has light absorbing properties, the light usage efficiency of the photosensitizer decreases, and this also causes a decrease in sensitivity, resulting in a significant decrease in sensitivity overall. However, the solubility of hydrophilic light-absorbing materials in resist solutions is low, making it difficult to obtain sufficient absorbance. We found that by selecting , it is possible to dissolve a sufficient amount to prevent the influence of reflection from the substrate, and to keep the decrease in sensitivity within a range that does not cause any practical problems, and we have arrived at the present invention. .

(Means for Solving the Problems) That is, the gist of the present invention is to provide an alkali-soluble resin and/or
, a positive photoresist composition comprising a compound containing a -2-su7toquinone diazide group, containing a light-absorbing material represented by the following structural formula in an amount of 0, /~/ Owt% of the total solids. It consists in a positive photoresist composition.

I In the formula, R1 represents an alkyl group of 01 to C6, R2 is an optionally substituted alkyl group, an optionally substituted alkyl group, -(0H2)Co2R8 group (R3 is a, ~
C6 alkyl group), Ar represents an optionally substituted aryl group.

Examples of these substituents include alkyl groups, aryl groups, halogen atoms, alkyloxycarbonyl groups, aryloxycarbonyl groups, perkylaminocarbonyl groups, arylaminocarbonyl groups, arylsulfoxy groups, and nitro groups.

To explain the present invention below, in the present invention, the presence of the 3-cyano-4-hydroxy-copyridone term and the azo group is 4@! i! 8, the pyridone ring portion has moderate hydrophilicity, which maintains a good balance with the lipophilic properties of other parts of the molecule, maintains solubility in the resist, and prevents a significant decrease in sensitivity. be. The azo group is also important as a chromophore. Examples of the light-absorbing material of the present invention include the following, but it is needless to say that the light-absorbing material is not limited thereto.

Compound■ ■ H8 CH1 1゜ 0,! Is CH3 ■ 01H.

TomiCH2001c2H5 Such a light-absorbing material can be easily synthesized by a known method, for example, according to the reaction formula below, but is not necessarily limited to this method.

R2 In the formula, R', R2, and Ar represent the same groups as those described in the claims, and X and Y represent C8 to C4 alkyl groups, which may be the same or different.

The amount of this light-absorbing material added is 0.0% based on the total solid content. /~
/ Owtchi, preferably 0. ! ~rvtchi. If the amount added is less than this, the anti-nolation effect will not be sufficient, and if it is more than this, precipitation will occur and the sensitivity will drop significantly, which is undesirable.

Alkali-soluble resins include hydroxy aromatic compounds such as phenol, cresol, ethylphenol, t-furfural, xylenol, naphthol, /, 4t-dihydroxybenzene, /I3-dihydroxybenzene, formaldehyde, acetaldehyde, p/zaldehyde,
So-called novolac resins obtained by condensation polymerization of aldehydes such as furfural, polyhydroxystyrene, derivatives thereof, and the like are preferably used. Further, if necessary, an alkali-insoluble resin such as polymethyl methacrylate, styrene, etc. may be blended with this to make the entire composition alkali-soluble.

/, the compound containing a konaphthoquinonediazide group is not particularly limited, but for example: r, Koaa
Author: Light-sensitive Syatem
g” (John Wiley & 5ons, engineering nc
)j4t,? ~3! Examples include compounds disclosed on page 1. Suitable examples include 7.2-penzoquinonediazide-dasulfonic acid ester, /, 2-naphthoquinonediazide-I-sulfonic acid ester, /, λ-naphthoquinonediazide-j-sulfonic acid ester, and the like. More preferably /1.2-naphthoquinone diazide! −
Sulfonic acid or /2.2-naphthoquinone diazide
Esters of goose sulfonic acid and polyhydroxy aromatic compounds are used.

Examples of polyhydroxy aromatic compounds include 2,3,41-trihydroxybenzophenone, 2,3,4t, 41'-
Tetrahydroxybenzophenone, querneptin, etc. are preferably used.

The ratio of the alkali-soluble resin and the compound containing a 2-naphthoquinone diazide group is 1 to 10 parts by weight, preferably 70 to 401 parts by weight, per 700 parts by weight of the resin.

Usually, these are used after being dissolved in a suitable solvent.

The solvent is not limited as long as it has sufficient solubility for the photosensitizer and resin and provides good coating properties, but examples include methylpyrrolidone, ethylamine lubricant, ethyl cellosolve acetate, and ethyl cellosolve acetate. cellosolve solvents such as butyl acetate, ester solvents such as amyl acetate, highly polar solvents such as di-, methylformamide, dimethylacetamide, N-methylpyrrolidone, or mixed solvents thereof, or aromatic hydrocarbons. Examples include those with added .

The above resist composition is coated on a substrate by a known method, exposed to light in a predetermined pattern, and developed to obtain a highly
A good resist image can also be obtained in the emissivity area.

The developing solution for the positive photoresist composition of the present invention includes inorganic alkalis such as sodium hydroxide, potassium hydroxide, sodium carbonate, sodium silicate, sodium metasilicate, aqueous ammonia, ethylamine, n-propylamine, etc. Primary amines, secondary amines such as diethylamine and di-n-propylamine, triethylamine,
Use tertiary amines such as methyldimethylamine, quaternary ammonium salts such as tetramethelammonium hydroxide, trimethylhydroxyethylammonium hydroxide, or products to which alcohol, surfactant, etc. are added. Can be done.

The positive photoresist composition of the present invention is useful not only for the production of VLSI but also for general xa! ! It is also useful for i-making, mask production, and offset printing.

(Example) Next, the present invention will be explained in more detail by giving specific examples.
The present invention is not limited in any way by the embodiments unless the gist of the invention is exceeded.

Examples/ m-cresol, p-cresol, 2. Novolak resin obtained by condensing j-xylenol with formaldehyde using oxalic acid as a catalyst (m-cresol/'p-cresol/2.j-xylenol concentration 3/g/3, MY=-
4,100) 100 parts by weight and 33 parts by weight of J, j, (t, g'-tetrahydroxy' benzophenone /, -naphthoquinone diazido!-sulfonic acid ester (average esterification rate 7!%) A photoresist base is prepared by dissolving 3/! parts by weight of ethyl cellosolve.

3 parts by weight (2 Mt% of total solids in the resist) of 3-cyano-d-hydroxy-
1-(p-impteroxylponylphenyl:/
)-4-Methyl-/-propyl-1-pyridone (compound ①) is dissolved.

The nine photoresist compositions obtained in this way were spread on a silicon wafer to a film thickness of 0 pTICfr? After prebaking in a clean oven for 0°C JO minutes, it was exposed using a reduction projection exposure system @ (@Canon IFPA/4/''), and λ,,?r
Develop with wt% tetramethylammonium hydroxide aqueous solution at 2j°C/min. The film thickness of the exposed part is exactly 0
The exposure 1 (Eth) was determined, and its reciprocal was defined as the sensitivity. Table 1 shows relative values to the sensitivity of a photoresist base material that does not contain a light-absorbing material.

Further, this resist was coated on an A1 evaporated substrate with a step of 7 μm, pattern exposed, and developed, and the resist image was observed at 81M. As a result, no thinning of the resist was observed even at the step, and the antihalation ability was sufficient.

In addition, as another indicator of antihalation ability, this resist composition was coated to a thickness of 80 pm on a quartz wafer, irradiated with a high-pressure mercury lamp, and the photosensitive material was completely bleached. The transmittance at the exposure wavelength was measured and was found to be 9A''J-4, 6WJ6H.

Example λ j-(m-chlorophenylazo)- in place of compound I
Evaluation was carried out in the same manner as in Example 1, except that 3 parts by weight (2.2 parts of total solids) of 3-cyano-6-hydroxydermef leu/propyl-2-pyridone (Compound ■) was used. The results are shown in Table/.

Comparative Example/N-methyluda-cyclohexylamino-/, a light-absorbing agent that does not have sufficient hydrophilicity, in place of Compound (1).

? -Napthalene dicarboxylic acid imide (Compound ■) Evaluation was performed in the same manner as in Example. The results are shown in Table 1, and there was a significant decrease in sensitivity.

Comparative Example λ Instead of Compound I, 3-methyl-, which has extremely strong hydrophilicity,
! Attempts were made to dissolve the -hydroxy/-(,2,nerdichlorodesulfophenyl)-p-(4tsulfophenylazo)-pyrazole disodium salt into the photoresist substrate, but virtually no dissolution occurred.

Comparative Example 3 Evaluation was carried out in the same manner as in Example/, except that 0.02 parts by weight (0.01% of the total solid content) of Compound (1) was used.・・・
The ration prevention function was not sufficient.

(Effects of the invention) According to the composition of the invention, even on a high reflectance substrate, N9
#A A photoresist with excellent controllability and superior sensitivity, resolution, heat resistance, and other considerations can be obtained, and can be very suitably used for the development of VLSIs and the like.

Sender: Mitsubishi Chemical Industries, Ltd. Representative Patent Attorney Hase - Others/names

Claims (1)

[Claims] (1) A positive photoresist composition comprising an alkali-soluble resin and a compound containing a 1,2-naphthoquinone diazide group contains 0.1 to 10 wt% of the total solids of a light-absorbing material represented by the following structural formula. A positive photoresist composition characterized by: ▲There are mathematical formulas, chemical formulas, tables, etc.▼ In the formula, R^1 represents an alkyl group of C_1 to C_6, and R^
2 is an optionally substituted alkyl group, an optionally substituted aryl group, -(CH_2)CO_2R^3 group (
R^3 represents an alkyl group of C_1 to C_6), and Ar represents an optionally substituted aryl group.