JPH03229256A - Photosensitive composition - Google Patents

Abstract

PURPOSE:To make improvement in shape controllability after development by incorporating a base resin having a phenolic hydroxyl group which is protected of the hydroxyl group by an allyl group or allyl group deriv. and a photoreaction initiator into the above compsn. CONSTITUTION:The base resin having the phenolic hydroxyl group which is protected of the hydroxyl group by the allyl group or allyl group deriv. and the photoreaction initiator are incorporated into this compsn. A disilane deriv. or the like which forms radicals by, for example, light, and initiates reaction by this formation is used as the photoreaction initiator. The formation of the fine patterns with the high accuracy, the good shape and the good shape controllability is executed even in the case of enhancing the resolution by using the exposing light of a short wavelength.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a photosensitive composition. The photosensitive composition of the present invention can be used, for example, as a photoresist for performing microfabrication in photolithography technology.

[Summary of the invention]

The photosensitive composition of the present invention contains at least a base resin having a phenolic hydroxyl group whose hydroxyl group is protected by an allyl group or an allyl group derivative, and a photoreaction initiator. This is a photosensitive composition with improved controllability.

[Background of the invention and problems to be solved]

Photosensitive compositions have conventionally been used in a number of fields.

For example, it is used as a photoresist used in photolithography technology for electronic materials, particularly semiconductor devices.

By the way, the minimum processing dimensions of semiconductor integrated circuits, for example, are becoming smaller year by year, and at the research and development level, e.g.
It has reached the level of less than μm. In order to form these fine patterns, we are trying to improve the resolution of conventional positive resists (such as resists consisting of a combination of naphthoquinone-1,2-diazide sulfonic acid ester and cresol novolak resin), and Attempts have been made to increase the numerical aperture of reduction projection exposure apparatuses using ultraviolet rays such as g-lines and i-lines emitted from high-pressure mercury lamps. However, it is no longer possible to meet the above-mentioned fine pattern level by improving the conventional techniques as described above, and accordingly, lithography techniques with even shorter wavelengths are attracting attention.

Among these, KrF excimer laser lithography technology (wavelength 250 nm) and ArF excimer laser lithography technology (wavelength 193 nm) are attracting attention.

However, in these excimer laser lithography techniques, the wavelength range of the laser light used is
Conventionally used resists, such as g-line and i-line resists (generally made of orthoquinonediazide and novolak resin), can be patterned to a certain extent, but the absorption is too large, and the pattern is triangular. The problem was that it became There was also a problem of poor controllability. [For conventional microfabrication resists, see Press Journal Inc. “Monthly Sem1
conductor World'', November 1987, pp. 91-100).

[Object of the Invention] The present invention solves the above problems and enables the formation of fine patterns with high precision and good shape with good shape controllability even when the resolution is increased using short wavelength exposure light. The purpose of the present invention is to provide a novel photosensitive composition that can be used.

[Means for solving problems]

In order to achieve the above object, the photosensitive composition of the present invention contains at least a base resin having a phenolic hydroxyl group whose hydroxyl group is protected by an allyl group or an allyl group derivative, and a photoreaction initiator. It is.

In the present invention, various kinds of base resins having a phenolic hydroxyl group to be protected by an allyl group or an allyl group derivative can be used, but the following can be exemplified as those that can be preferably used. That is, poly-p-hydroxystyrene, a copolymer of p-hydroxystyrene and alkyl-substituted hydroxystyrene, a copolymer of p-hydroxystyrene and methyl tag acrylate, a cresol novolac resin alone, or Two or more of the above can be used in combination.

In the present invention, an allyl group (ally1 group) or an allyl group derivative is one that has the structure of an allyl group CHz=CHCHz- or an allyl group, or has a substituent attached to an allyl group, and has the same chemical reaction as an allyl group. Refers to a group that can exhibit certain behaviors. Examples of such allyl groups or allyl group derivatives include allyl groups, crotyl groups, α, β-methallyl groups, prenyl groups, cinnamyl groups, methylmethacrylic groups, and 2-hydroxyethylmethacrylic groups.

In the present invention, as the photoreaction initiator, for example, one that generates radicals by light and thereby initiates the reaction can be used. For example, a disilane derivative or the like can be used as a compound that generates radicals with light.

As the disilane derivative, a disilane derivative represented by the following formula (CI) can be used.

-Rear margin (N R'-R' each independently represents an aryl group or an alkyl group (each group includes a substituent).However, at least two or more of R1-Rh are aryl groups. It is the basis.

The compound represented by the general formula CI) generates radicals when irradiated with light, and for example, generates radicals at 250 nm, which is the oscillation wavelength of KrF excimer laser light.

Among the compounds represented by general formula (1), those in which two or more of R1 to R6 are aryl groups or aryl groups having substituents are preferable from the viewpoint of solubility in resin and absorption wavelength. . Generally, as the aryl group component increases, the absorption maximum approaches the absorption at 250 nm from the shorter wavelength side.

Preferred specific compound examples of the disilane derivative represented by the general formula [1] include 1,1,2.2-tetraphenol dimethyldisilane, 1,2-diphenyltetramethyldisilane, 1.1.1-trimethyldisilane, Examples include phenoltrimethyldisilane.

However, the photoreaction initiator that can be used is not limited to the compounds represented by general formula (1), such as the above-mentioned exemplified compounds.

As a photoinitiator, azobisisobutyronitrile,
L-butyl hydroperoxide and the like can be used.

[For production]

As is conventionally known, allyl phenyl ether (allylphenoxyto), which is a compound having a phenolic hydroxyl group whose hydroxyl group is protected by an allyl group or an allyl group derivative, undergoes the following rearrangement reaction. The phenolic hydroxyl group is exposed.

The second rearrangement reaction is generally performed by heating (e.g. heating to 200°C)
It is called Claisen rearrangement.

On the other hand, the photosensitive composition of the present invention contains a resin having a phenolic hydroxyl group whose hydroxyl group is protected by the allyl group, etc., and a photoreaction initiator. The photoreaction initiator is activated, and the radicals generated thereby are added to the double bond of the allyl group, etc., and the allyl residue disappears. Therefore, the above-mentioned dislocation does not occur even after heating or the like.

As a result, in the photosensitive composition of the present invention, the phenolic hydroxyl group is not exposed in the light-irradiated portion even when heat is applied, whereas the phenolic hydroxyl group is exposed in the light-irradiated portion.

This makes it possible to form a pattern using the photosensitive composition of the present invention.

That is, as schematically illustrated in FIG.
The phenolic hydroxyl group of the portion 11 irradiated with ν is protected, and the phenolic hydroxyl group of the other portion 12 is exposed. Therefore, when this is developed using, for example, an alkaline solution as a developer, a negative pattern 21 is obtained in which only the exposed areas remain, and when developed using an organic solvent as a developer, a positive pattern 22 is obtained in which only the non-exposed areas remain. Given.

Here, as the alkaline developer, an organic alkaline developer mainly consisting of an aqueous tetramethylammonium hydroxide solution or an inorganic alkaline developer such as an aqueous potassium hydroxide solution can be used. These alkaline developers may contain a surfactant (for example, Florade). Further, as the organic developer, a low polar solvent such as xylene, hexane, heptane, decalin, toluene, benzene, chlorobenzene, etc. can be used.

In FIG. 1, 3 is an exposure mask, and 4 is a substrate (semiconductor substrate, etc.) on which the photosensitive composition 1 is applied in the form of a film.

[Examples] Examples of the present invention will be described below. However, it goes without saying that the present invention is not limited to the examples described below.

Example-1 In this example, the base resin was obtained as follows.

That is, as a poly p-hydroxystyrene resin, Linker-M (weight average molecular weight = 3.200
) was hydrogenated and purified.

The hydrogenated resin was allylated using an excess amount of allyl chloride in the presence of sodium hydroxide, thereby obtaining a base resin having a phenolic hydroxyl group whose hydroxyl group was protected by an allyl group. The average allylation rate is NM
According to R measurement, it was 60%.

For the base resin obtained above, as a photoreaction initiator,
A photosensitive composition was prepared by adding a disilane derivative, 1,1,2,2-tetraphenyldimethyldisilane, in an amount corresponding to 20% by weight of the base resin. Ethyl cellosolve (ECA) was used as the solvent.

The photosensitive composition thus obtained is referred to as Composition-1.

A 5-inch diameter silicon semiconductor wafer that had been subjected to dehydration beta treatment at 200''C was subjected to HMDS (hexamethyldisilazane) vapor treatment for 1 minute at room temperature to make the surface hydrophobic, and then the above composition was applied onto the silicon wafer. 1 to 0.2μ
The coating liquid was filtered through a membrane filter of 1.0 m, and the coating solution was spin-coated to form a resist layer with a thickness of 1 μm, and then betaened at 90° C. for 120 seconds. This is sample-1
shall be. Two types of samples were prepared: one for alkaline development (for negative pattern formation) and one for organic solvent development (for positive pattern formation). This was applied with a KrF excimer laser stepper (NA: 0.37, σ: 0.5) with a wavelength of 248 nm.
Exposure was performed using a mask for forming a 4 μm line and space pattern. The exposure amount was as shown in Table 1 for each of alkaline development and organic solvent development. after that,
FEB (post-exposure beta) was applied at 160°C for 10 minutes. Development is 2.38tmt for alkaline development.
% of tetramethylammonium hydroxide (T
MAH) aqueous solution was used as a developing solution, the film was developed by dipping it in this for 60 seconds, and was washed with water.

Regarding organic solvent development, xylene was used as a developer, and development was performed by dipping in this for 60 seconds. Table 1 shows the results of evaluating the quality of the formed pattern shape by observing the obtained pattern with a SEM. In Table 1, ◎ indicates that the pattern shape is extremely good, O indicates that the pattern shape is excellent, and Δ indicates that the pattern shape is poor.

In addition, compositions-2 to 2, which are photosensitive compositions, were prepared in the same manner as composition-1 except that a base resin whose phenolic hydroxyl group was protected by the resin and allyl component shown in Table 1 was used.
Samples 2 to 6 were obtained using each sample. Comparative examples shown in Table 1 were also created. These were treated and evaluated in the same manner as above. However, for samples-5 and 6, PE
B treatment was performed at 130°C for 10 minutes. The results are summarized in Table 1.

From Table 1, when patterns were formed using Samples-1 to 6 using the photosensitive compositions-1 to 6 of the present invention, the pattern controllability was good, as is clear from the comparison with the comparative examples. ,
It can be seen that a good pattern shape can be obtained.

〔Effect of the invention〕

As described above, the photosensitive composition of the present invention allows a fine pattern with good resolution to be obtained with high precision using short wavelength exposure light, and also has a good pattern shape and good shape controllability. It was good. Moreover, the photosensitive composition of the present invention is a composition constructed based on a completely new idea, and furthermore, by changing the developing means, it can be used as either a negative resist or a positive resist. It also has advantages.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram for explaining the present invention in detail. DESCRIPTION OF SYMBOLS 1... Photosensitive composition, 11... Exposed part, 21...
・Negative pattern, 22...Positive pattern.

Claims (1)

[Scope of Claims] 1. A photosensitive composition comprising at least a base resin having a phenolic hydroxyl group whose hydroxyl group is protected by an allyl group or an allyl group derivative, and a photoreaction initiator. 2. The base resin is from the group consisting of poly-p-hydroxystyrene, a copolymer of p-hydroxystyrene and alkyl-substituted hydroxystyrene, a copolymer of p-hydroxystyrene and methyl tag acrylate, and a cresol novolak resin. The photosensitive composition according to claim 1, comprising at least one arbitrarily selected photosensitive composition.