Radiation imagery chemistry: process – composition – or product th – Imaging affecting physical property of radiation sensitive... – Forming nonplanar surface
Patent
1996-08-05
1997-03-25
Chu, John S.
Radiation imagery chemistry: process, composition, or product th
Imaging affecting physical property of radiation sensitive...
Forming nonplanar surface
430167, 430197, 4302811, 4302831, 430330, 430906, G03F 7012, G03F 7037
Patent
active
056143540
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
The present invention relates to a method of forming a positive polyimide pattern by exposure to actinic radiation of a radiation-sensitive polyimide precursor, and particularly relates to a method of forming a positive polyimide pattern by exposure of an actinic radiation-sensitive polyimide precursor.
BACKGROUND TECHNIQUES
The following methods have been known as methods of forming polyimide patterns which use a composition of actinic radiation-sensitive polyimide precursors. carbon-carbon double bond which can be dimerized or polymerized by exposure to actinic radiation and wherein an amino group or a quaternary salt thereof are added to polyamic acid (disclosed, for example, in U.S. Pat. No. 4,243,743). polyamic acid with acrylamide added thereto (disclosed in, for example, EP Laid-open No. 430220) . radiation-sensitive polyimide precursors wherein a photosensitive group is introduced to polyamic acid with ester group.
However, all of these processes are of negative type wherein the film in portions exposed to the radiation remains, because the irradiated pattern is developed in such a state that the film in the exposed portion has photo-cured to a greater degree than that of the unexposed portion. In negative type processes, dust on the mask used in exposure leads to a defect produced therein resulting in pin holes formed in the polyimide film. For this reason, there have been problems such as low yield of production and low reliability particularly where the polyimide coating is used as a protective layer for semiconductor elements or as an inter-layer insulation layer for multi-layer wiring in high-density packaging. Thus there has been a demand for a method of forming positive polyimide patterns by means of a composition of actinic radiation-sensitive polyimide precursors.
The following processes have been disclosed as methods of forming positive polyimide patterns by means of an actinic radiation-sensitive composition of polyimide precursors. radiation-sensitive polyimide precursors obtained by introducing a photo-degradable photosensitivity to polyamic acid with ester group (disclosed in, for example, Japanese Patent Laid-Open No.1-61747). naphthoquinonediazide compound of a particular molecular structure is added to polyamic acid having a particular structure and heat treatment within a particular temperature range is applied after exposure (disclosed, for example, in Polymer Preprints, Japan, vol.40, No.3, 821, (1991))
However, the processes described above have not been put into practice due to problems such as complicated process of preparing the composition of actinic radiation-sensitive polyimide precursors and lack of photosensitivity.
Accordingly, an object of the invention is to provide a process of forming an excellent positive polyimide pattern by using a composition of actinic radiation-sensitive polyimide precursors which can be easily manufactured.
Another object of the invention is to provide a process of forming a positive polyimide pattern having excellent photo-reactivity (photosensitivity, etc.).
Further another object of the invention is to prevent the yield of production and reliability from decreasing when the polyimide film is used as the protective layer for semiconductor elements or inter-layer insulation layer for multilayer wiring of high-density packaging substrate .
DESCRIPTION OF THE INVENTION
According to the invention, such an unexpected effect can be achieved by forming positive polyimide patterns through a composition of actinic radiation-sensitive polyimide precursors which has only been used in forming negative patterns.
Use of the composition of actinic radiation-sensitive polyimide precursors which has only been used in forming negative patterns is practical because it can be more easily manufactured than the compositions which have been known as the materials to form positive patterns.
Also the positive polyimide pattern formed according to the invention has excellent photo-reactivity (photosensitivity, etc.).
Because positive polyimid
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Asano Masaya
Eguchi Masuichi
Kusano Kazutaka
Chu John S.
Miller Austin R.
Toray Industries Inc.
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