Radiation curable composition, storing method thereof, forming method of cured film, patterning method, use of pattern, electronic components and optical waveguide

Abstract

The present invention provides a radiation curing composition comprising (a): a siloxane resin, (b): a photoacid generator or photobase generator, and (c): a solvent capable of dissolving component (a) and containing an aprotic solvent.

Description

RELATED APPLICATIONS [0001] This is a continuation-in-part application of application Ser. no. PCT / JP2004 / 14850 filed on Oct. 7, 2004, now pending.BACKGROUND OF THE INVENTION [0002] 1. Field of the Invention [0003] The present invention relates to a radiation curable composition, a storing method thereof, a forming method of a cured film, a patterning method, an use of a pattern, electronic components and an optical waveguide. [0004] 2. Related Background of the Invention [0005] As insulating films for use in LSIs and PDPs there have conventionally been used SiO2 films formed by CVD methods, and organic SOG (Spin On Glass) or inorganic SOG films formed by coating methods, because of their excellent heat resistance and electrical reliability. With insulating films of the prior art, however, it is impossible to directly form wiring grooves or contact holes, and usually a photoresist is patterned on the insulating film, followed by either dry etching with plasma or wet etching with a c...

AI Technical Summary

Benefits of technology

[0038] The mechanism responsible for the exhibited effect of the invention, which has not been achieved in the prior art, is not yet fully understood. However, the present inventors conjecture that the reduced exposure dose required for curing according to the invention is realized because, for instance, there is no need to use an acid diffusion controller to inhibit diffusion of generated acid, and an aprotic solvent is used as the solvent to accelerate curing.

[0039] When a curing acceleration catalyst is further included as an additive, the effect described above is exhibited more prominently. This is attributed to the fact that the radiation curable composition can be more thoroughly cured at a lower exposure dose.

[0040] The improvement in pattern precision is assumed to result because the curing reaction of the radiation curable composition occurs before diffusion of the acid when an aprotic solvent is used as the curing acceleration solvent. Addition of a curing acceleration catalyst as an additive also further improves the pattern precision. This is attributed to the fact that the curing reaction occurs at a more rapid timing. This mechanism differs from the mechanism of the prior art, whereby the acid diffusion controller inactivates (neutralizes) the generated acid to improve the pattern precision. According to the invention, it is conjectured that both pattern precision improvement and exposure dose reduction can be achieved based on the aforementioned mechanism which is different from that of the prior art.

[0041] The radiation curable composition, method for its storage, forming method of a cured film and patterning method of the invention can produce cured films with excellent pattern precision at relatively low exposure doses. The present invention is therefore useful for uses of a pattern, electronic components and optical waveguides.

Problems solved by technology

However, when the present inventors conducted a detailed investigation of patterning using such conventional insulating film materials imparted with photosensitive properties, it was found that when employing the photosensitive resin compositions comprising an alkali-soluble siloxane polymer, a photoacid generator and a solvent, from which the water and catalyst have been removed as disclosed in Patent documents 1 and 2, for example, a large light exposure dose is required in both cases, and therefore mass production cannot be advantageously accomplished.

In addition, when using the photosensitive polysilazane compositions comprising polysilazane and a photoacid generator, as disclosed in Patent documents 3 and 4, the light exposure dose is low but the steps of dipping in purified water after exposure or steps requiring humidification treatment are obviously complicated, making it difficult to obtain high pattern precision.

Nevertheless, since the acid diffusion controller inactivates (neutralizes) the acid, the curing property is impaired in cases with a low amount of photoacid generator or a low exposure dose, thereby often leading to lower pattern precision.

Conversely, increasing the exposure dose in an attempt to improve the patterning precision is clearly an unsuitable strategy for mass production.

This requires an increased exposure dose for generation of extra acid to compensate for the inactivation, and therefore it has been difficult to achieve both improvement in pattern precision and reduction in exposure dose.

However, the basic concepts of such strategies have not been elucidated, nor have radiation curable compositions suited for such strategies existed.

Nevertheless, when patterning is carried out using conventional radiation curable compositions, reducing the amount of acid generated prevents curing from proceeding to an adequate degree.

In addition, curing of the exposed sections also fails to adequately proceed when the temperature of the post-exposure baking (PEB) step after exposure is lowered or PEB is not carried out.

As a result, it has been difficult to form highly precise patterns.

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