Precursor composition for positive photosensitive resin and display made with the same

#The present invention relates to a positive photosensitive resin precursor composition, the UV-exposed portion of which dissolves in an alkaline aqueous solution, suitable for use in surface protection films and interlayer insulating films of semiconductor elements and insulating layers for organic electroluminescent elements. The present invention also relates to a display device using the precursor composition.

#Regarding the positive heat-resistant resin precursor compositions, the exposed portion of which dissolves in an alkaline developer, those prepared by adding a naphthoquinone diazide to a polyamic acid (Japanese Unexamined Patent Application Publication No. 52-13315, U.S. Pat. No. 4,093,461), those prepared by adding naphthoquinone diazide to a soluble polyimide having a hydroxyl group (Japanese Unexamined Patent Application Publication No. 64-60630, European Patent No. 264678A1), and those prepared by adding a naphthoquinone diazide to polyamide having hydroxyl groups and (Japanese Unexamined Patent Application Publication No. 56-27140, European Patent No. 23662A1) are known in the art.

#In a composition containing a common polyamic acid and naphthoquinone diazide, the effect of naphthoquinone diazide that decreases the solubility in an alkaline solution is weak compared to the solubility of the carboxyl groups in the polyamic acid. Thus, a desired pattern cannot be obtained in most cases, which is a problem. In order to control the alkali solubility of the polyamic acid, a polyamic acid derivative in which a carboxyl group of the polyamic acid is protected by an ester group has been developed. However, in a composition containing this polyamic acid derivative and naphthoquinone diazide, the effect of the naphthoquinone diazide to decrease the solubility in an alkaline solution becomes excessively strong. As a result, although desired patterns can be obtained, a dramatic decrease in the sensitivity occurs, which is a problem.

#The present invention will now be described by way of examples and technologies. These examples do not limit the scope of the present invention. The evaluation of the examples of the photosensitive heat-resistant resin precursor composition is conducted by the methods described below.

#Preparation of Photosensitive Polyimide Precursor Film

#A photosensitive heat-resistant resin precursor composition, hereinafter referred to as the “varnish”, was applied on a 6-inch silicon wafer. The thickness thereof was adjusted to ensure a thickness of 7 μm after pre-baking. Subsequently, the varnish was pre-baked for 3 minutes at 120° C. using a hot plate (Mark-7, manufactured by Tokyo Electron Ltd.) so as to obtain a photosensitive polyimide precursor film.