Negative photosensitive resin composition, method of forming a pattern and electronic parts

A negative photosensitive resin composition, which comprises;

• a thermosetting polymer precursor which can be cured through cyclodehydration upon heating;
• a latent heat cure accelerator which is capable of changing into a compound exhibiting a heat cure accelerating property through a reaction with an acid;
• and
• a photo-acid generating agent which is capable of generating an acid upon irradiation of light, wherein the compound formed by the reaction of the latent heat cure accelerator and the photo-generated acid accelerates the cyclodehydration of the thermosetting polymer precursor upon heating the negative photosensitive resin composition.

A method of forming a pattern, which comprises the steps of;

• coating a negative photosensitive resin composition comprising a thermosetting polymer precursor which can be cured through cyclodehydration upon heating and a photosensitive heat cure accelerator comprising a compound having a protective substituent group which can be eliminated upon irradiation with light on a surface of a substrate;
• forming a resin layer by heat-drying the coated photosensitive resin composition at a temperature of not more than 180° C.;
• irradiating light onto a predetermined region of said resin layer;
• heat-treating said resin layer during or after the light-irradiating step at a temperature ranging from 50 to 200° C.;
• and
• developing the heat-treated resin layer by dissolving and removing portions of said resin layer which are not subjected to the light-irradiation by making use of a developing solution
• wherein after irradiation with light the photosensitive heat cure accelerator accelerates the cyclodehydration of the thermosetting polymer precursor upon heating the negative photosensitive resin composition.