JPS6269263A - Photosensitive composition - Google Patents

Abstract

PURPOSE:To obtain the pattern having an excellent resolution by incorporating a compd. having a substd. or an unsubstd. O-nitrobenzyl group binded in the hydroxy group of a phenol to the titled composition. CONSTITUTION:The titled composition contains the compd. binded the substd. or unsubstd. O-nitrobenzyl group to the hydroxy group of the phenol. As the substd. or unsubstd. O-nitrobenzyl group binded to the hydroxy group of the phenol, the O-nitrobenzyl etc., is used. The substituting ratio of the O-nitrobenzyl group to the hydroxy group of the phenol depends on the kind of a resin contg. the phenol nucleus, the kind of a solvent, the alkaline solution used in a developer and a balance of a sensitivity, a contrast and a solubility. For example, when the weight average molecular weight of the polyvinyl phenol is 8,000, the substituting ratio is 5-100%, preferably 10-100%.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a photosensitive composition, and more particularly to a photosensitive composition that is alkali developable and forms a positive image with excellent resolution.

[Technical background of the invention and its problems]

Photosensitive compositions are utilized in many lithographic processes including semiconductor device manufacturing. Examples of photosensitive compositions forming positive carriers include mixtures of alkali-soluble novolac resins and poorly alkali-soluble dissolution inhibitors such as substituted O-naphthoquinone diazide compounds, Photosensitive compositions containing quinonediazide sulfonic acid esters, compositions using polyvinylphenol instead of novolak, and the like are currently widely used. Substituted O-naphthoquinone diazide is alkali-insoluble before light irradiation, but becomes alkali-soluble upon light irradiation, and the novolak resin and polyvinylphenol form an alkali-soluble round shape in the irradiated area. The dissolution rate for alkali increases compared to the non-irradiated area. Final -IjRVi, obtained by treatment of these irradiated areas with an alkaline developer. Whether or not a pattern with good resolution can be obtained depends on the factors before and after exposure,
One of the factors is whether a large difference in dissolution rate can be maintained in a developer having a constant alkaline concentration.

In some cases, surfactants are added to the developer to increase this difference in solubility, but if the difference in dissolution rate is not large enough, subtle changes in the alkali solubility of the developer will be affected. There is a risk that the quality of the resulting patterns will be greatly affected, and production management will become a national crisis. Furthermore, when a surfactant is added, there are drawbacks such as poor sensitivity and difficulty in controlling the amount of surfactant added.

[Purpose of the invention]

An object of the present invention is to provide a photosensitive composition that is alkali developable and forms a positive 1ljii image with excellent resolution.

[Summary of the invention]

In view of these points, the present inventors have conducted intensive studies and found that a photosensitive composition containing resin gold having a phenol skeleton contains a compound in which the hydroxyl group of phenol is substituted or has no 1i% O-nitrobenzyl group bonded to it. The present invention was achieved by discovering that a photosensitive composition satisfies this purpose.

That is, the present invention is characterized in that a photosensitive composition containing a resin having a phenol skeleton, which is subjected to RS development in an alkaline solution, contains a compound in which a substituted or mA-free O-nitrobenzyl group is bonded to the hydroxyl group of phenol. It is a photosensitive composition.

Any resin having a phenol skeleton can be used as long as it is soluble in an alkaline solution.

Examples include novolac resins, homopolymers of hydroxylated polystyrene or copolymers with methyl methacrylate, homopolymers of hydroxylated poly-α-methylstyrene, or copolymers with acrylonitrile, styrene, etc. These polymers used include if!
1. Moss or moss with a thickness of 2 or more can be arbitrarily used.

Examples of the IN-substituted or unsubstituted O-nitrobenzyl group bonded to the hydroxyl group of phenol include 0-nitrobenzyl,
4-methoxy-2-nitrobenzyl, 4.5-dimethoxy-2-nitrobenzyl, 4.5.6 trimethoxy 2
-nitrobenzyl, 3-methyl-2-nitrobenzyl,
4-Methyl-2-nitrobenzyl, 4.5-dichloro-2-nitrobenzyl, 2-di121:l-6-nitrobenzyl, 5-chloro-2-nitrobenzyl, 6-
Examples include nitrohyheronyl.

The introduction rate of 0-nitrobendi/I/ groups to the hydroxyl groups of phenol varies depending on the type of resin having a phenol skeleton used, the type of solvent, the alkaline solution used as a developer, etc., and depends on sensitivity, contrast, solubility, etc. Determined from 7 bars. For example, for polyvinylphenol with a weight average molecular i of 8,000, it is 5 to 100%.
Preferably it is 10-100%.

In the photosensitive composition of the present invention, an O-benzoquinonediazide sulfonic acid ester-naphthoquinonediazide sulfonic acid ester compound is used as a photosensitizer.

Next, a specific example of the use of the photosensitive composition of the present invention will be described. The photosensitive composition is dissolved in a t-solvent such as cyclohexanone, ethyl cellosolve acetate, methyl ethyl ketone, etc. and placed on a support such as a silicon wafer, for example. After spin coating and drying (50°C to 180°C, preferably 70°C to 120°C, 30 seconds to 90 minutes, preferably 1
For example, the film is exposed to ultraviolet light in an appropriate wavelength range through a mask (for 60 minutes to 60 minutes) in accordance with a conventional method. The appropriate wavelength is 200-5QQnm, preferably 300-450nm.
rl111 is used. Development is then carried out with a suitable alkaline IJM solution. Then dry (100℃~20℃)
0e, preferably 120°C to iso°C, 30 seconds to 12
0 minutes, preferably 1 minute to 90 minutes), and the support, e.g. a silicon wafer, is processed by conventional steps such as etching and metallization.

[Embodiments of the invention]

Examples will be described in detail below.

Example 1 O-nitrobenzyl etherification of if,l:'nylphenol was carried out.

P-vinylphenol (MW-, -8,000) 10
The solution was dissolved in 1 t of acetone and stirred at room temperature. Na
I400? , O-nitrobenzyl chloride 80f, K
2CO380f was added and stirred at room temperature for 12 hours. When the filtered filtrate was poured into 3 tons of water, a precipitate was formed, and the precipitate was collected by filtration, further washed with 3 tons of water, and dried to obtain 150 fti of the desired O-nitrobenzyl ether of vinylphenol. The O-nitrobenzyl etherification rate was about 50%.

O-nitrobenzyl ether compound 20 thus obtained
A resist solution consisting of 3.2 t of naphthoginonediazide sulfonic acid diester of y, 2,3,4-trihydroxybenzophenone and 80 t of ethylserone lupacetate was prepared by rA, applied on a silicon wafer with a spinner, and dried on a hot plate ( 90℃.

5 minutes) to form a photoresist film with a thickness of 1.5 μm. This substrate was then exposed to light for 10 seconds using a 250 W ultra-high pressure mercury lamp and a quartz mask. The thus obtained substrate was developed with a 2.4% aqueous solution of tetramethylammonium hydroxide, and then washed with water.
Hot plate top roll 11! (140℃.

After 5 minutes), a pattern consisting of 30.5 μm lines and spaces was obtained.

On the other hand, when P-vinylphenol that was not etherified was treated in the same manner as in Example 1, the diameter was 0.5 μm.
line and space patterns were not resolved.

Example 2 4-chloro-2-
An open surface was obtained in which 30% of ditropendyl ether groups were introduced. When the same process as in Example 1 was performed using this, a pattern force consisting of 0.5 μm lines and spaces 1
Obtained. In addition, as a result of pattern exposure using this photosensitive agent with a reduction projection exposure device using light of 355 ntn, the result was 0.
．． A pattern consisting of 7 μm lines and spaces was obtained.

〔Effect of the invention〕

As described above, by using the photosensitive composition of the present invention, a pattern with excellent resolution can be obtained.

Claims (1)

[Claims] A photosensitive composition containing a resin having a phenol skeleton, which is developed with an alkaline solution and is characterized by containing a compound in which a substituted or unsubstituted O-nitrobenzyl group is bonded to a phenol hydroxyl group.