1. Field of the Invention
The present invention relates to a method for removing a chemically amplified positive photoresist composition.
This application claims priority from Japanese Patent Application No. 2003-415126 filed on Dec. 12, 2003, the disclosure of which is incorporated by reference herein.
2. Background Art
(1) As disclosed in Japanese Patent Application, First Publication No. Hei 6-148889, Japanese Patent Application, First Publication No. Hei 6-230574, Published Japanese Translation No. 2002-529552 of the PCT Application and Japanese Patent Application and First Publication No. 2000-292927, various positive photoresist compositions have hitherto been proposed and put into practical use.
(2) As means for improving the heat resistance of a resist pattern, a method of subjecting to a heat treatment referred to as postbaking of ultraviolet-curing a resist pattern has been proposed.
(3) A trial of forming a resist pattern having high heat resistance includes the use of a negative photoresist composition.
(4) Various positive photoresist compositions having high heat resistance have been reported.
For example, a composition comprising an alkali soluble resin such as polyhydroxystyrenic resin or novolak resin, a compound having a vinyl bond at both ends and a photo acid generator is cheaper than a conventional i-ray novolak-based resist and is also a resist having high heat resistance, high sensitivity and high resolution.
(5) There has been known a composition comprising a reaction product of an alkali soluble resin such as polyhydroxystyrenic resin or novolak resin and a compound represented by the following general formula (I), and a photo acid generator.
However, in the case of (1), the positive photoresist composition is inferior in heat resistance of the unexposed area (resist pattern) and it was difficult to apply to fields which require high heat resistance.
In the case of (2), the resist pattern modified by the heat treatment has high heat resistance. However, it becomes difficult to remove a resist pattern in the case of a treatment with a remover containing a conventional organic solvent and thus the resist pattern must be removed under very severe conditions by an ashing treatment.
In the case of (3), the negative photoresist composition is inferior in sensitivity and resolution as compared with the positive photoresist composition and it is required to perform an ashing treatment so as to remove a resist pattern, and thus causing problems such as complicated work-in-process, high production cost and high load on a substrate.
In the case of (4) and (5), although a resist pattern having very high heat resistance can be formed, the resist pattern must be removed under very severe conditions similar to case of (2) and (3).
Therefore, there has been required to develop a method which can form a resist pattern having excellent heat resistance regardless of the use of a positive photoresist composition having excellent resist characteristics and also can remove the resist pattern having excellent heat resistance in a simple manner.