The present inventors have conducted elaborated studies with the aim of developing a polyamide acid, i.e. polyimide precursor, having {HEAD ~ photosensitive groups} in {TAIL ~ its main chain} which is endowed with about 20 100 times as high a photosensitivity as that of prior products and a heat resistance of 400° C. or above after dehydration cyclization 
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The present inventors have conducted elaborated studies with the aim of developing a polyamide acid , i.e. polyimide precursor , having { HEAD ~ photosensitive groups } in { TAIL ~ its main chain } which is endowed with about 20 100 times as high a photosensitivity as that of prior products and a heat resistance of 400 ° C. or above after dehydration cyclization
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