Photosensitive resin precursor composition

#1. Field of the Invention

#The present invention relates to a photosensitive resistant resin precursor composition having an excellent film thickness uniformity and which is suitably used for a surface protection layer and an insulating interlayer of a semiconductor element, an insulating layer of an organic electroluminescent device, and the like.

#2. Description of the Related Art

#A heat resistant resin precursor polymer of the present invention is formed to a ring structure, such as an imide ring, an oxazole ring, or a thiazole ring by heating or with an adequate catalyst, thereby resulting in a heat resistant resin. The ring structure increases the heat resistance and solvent resistance of the resulting resin. Preferably, the heat resistant resin precursor polymer is polyamic acid or polyamic ester, which are a polyimide precursor, or polyhydroxyamide, which is a polybenzoxazole precursor, but it is not limited to these. For a positive photosensitivity, preferably, the heat resistant resin precursor polymer is essentially composed of a structural unit expressed by general formula (3). For a negative photosensitivity, preferably, the polymer is essentially composed of a structure unit expressed by general formula (4).

#Formula (3) expresses a polyamic acid having a hydroxy group. The hydroxy group increases the solubility of the polymer in an alkaline developer to be higher than that of other polyamic acids having no hydroxy group. In particular, the hydroxy group is preferably phenolic from the viewpoint of the increase of the solubility in alkaline developers. Also, the presence of 10 percent by weight or more of fluorine in formula (3) increases the repellency of the interface of the film to some extent, and, thereby, prevents an alkaline developer from penetrating into the interface. Unfortunately, a fluorine content of more than 20 percent by weight leads to reduced solubilities in alkaline developers and fuming nitric acid and causes the resistance to organic solvents of the polymer formed to a ring structure by heat treatment to deteriorate. Accordingly, the fluorine content is preferably set in the range of 10 to 20 percent by weight.

#In formula (3), R11 represents a structural constituent of an acid dianhydride or a dicarboxylic acid, and is preferably an organic group having a valence in the range of 2 to 8 and a carbon number of at least 2, containing an aromatic group and one to four hydroxy groups. More preferably, the carbon number is in the range of 6 to 30 and the valence is 3 or 4.