Photosensitive polyimide adhesive sheet
Positive tone Photosensitive Polyimide B-stage sheet which was composed of transparent soluble polyimide, naphthoquinone diazide compound, thermal cross linker and solvent, was developed. We designed new polyimide structure and cross linker suitable for photosensitive polyimide sheet. The photosensitive sheet shows fine pattern formation capability as well as good thermal stability and mechanical properties. It is quite easy to obtain flat surface on topological surface to laminate the photosensitive sheet.
Novel Partial Esterification Reaction in Poly(amic acid) and Its Application for Positive-Tone Photosensitive Polyimide Precursor
We found novel quantitative esterification in poly(amic acid) (PAA) by reacting with N,N-dimethylformamide dialkyl acetals (DFAs). Different alkyl ester was obtained by changing the alkyl group in DFAs. The esterification ratio was determined by amount of DFAs. The reaction proceeds under mild condition without any catalysis. It has not been reported such a kind of quantitative partial esterification before. The partial esterification allowed us to control the solubility of PAA to alkaline solutions. The strict solubility rate control to alkaline solution of PAA was quite important for positive tone photosensitive polyimide (posi PSPI). The partial esterification of PAA gave us a way to strict dissolution control. By using it, we could obtain posi PSPI just mixing with diazonaphthoquinone compound.
The chemistry of formamide acetals
Abstract The formamide acetals enter into two main categories of reactions, namely alkylation and formylation. As alkylating agents, they have been used in the synthesis of esters from acids, ethers and thioethers from phenols and aromatic and heterocyclic thiols, and the alkylation of active methines. As formylating agents, formamide acetals are useful in the synthesis of enamines from active methylenes and amidines from amines and amides. Also formamide acetals are efficient reagents for the conversion of α-hydroxycarboxylic acids to alkenes while trans-vic-diols yield epoxides. The above conversions as well as othere listed in the review proceed in almost all cases under mild conditions in high yields making these reagents valuable synthetic tools.