Temperature photosensitive polyimide

Photosensitive functions are in many cases also heat sensitive, so the preparation of photosensitive polyimides needs smooth conditions for the condensations and imidization reactions. Some chemical reactants, which can be used for polyamide preparation, have been patented for the synthesis of polyimides and polyimide precursors. For example, chemical imidization takes place at room temperature by using phosphonic derivative of a thiabenzothiazoline.102 A mixture of N -hydroxybenzotriazole and dicyclohexylcarbodiimide allows the room temperature condensation of diacid di(photosensitive) ester with a diamine.103 Dimethyl-2-chloro-imidazolinium chloride (Fig. 5.25) has been patented for the cyclization of a maleamic acid in toluene at 90°C.104 The chemistry of imidazolide has been recently investigated for the synthesis of polyimide precursor.105 As shown in Fig. 5.26, a secondary amine reacts with a dianhydride giving meta- and para-diamide diacid. The carbonyldiimidazole... 

The differences between the curing of the polyamic acids and their tertiary amine salts or esters is even larger. The Toray Photoneece photosensitive polyimide (which is a tertiary amine salt of BTDA/ODA polyamic acid) begins reacting at much lower temperatures and the reaction is completed faster during the temperature ramp (see Table 2 and Figure A). This effect is consistent with work of Kruez et al. (O on tertiary amine salts of PMDA/ODA polyamic acid. 

Solvent-Developed Photosensitive Materials. Many of the limitations of the bilayer polyamic acid process have been overcome through the use of photosensitive polyimides (9). Formulated photosensitive products have been developed that result in improved process capability resulting in increased pattern resolution, improved soft bake time and temperature process latitude, and improved lithographic process latitude and throughput while maintaining desired film physical properties. Moreover, the film patterning process requires fewer steps... 

Highly aromatic and photosensitive polymers such as polyimides are potential candidates in photonic applications. Wholly aromatic polyimides (XXXV) were observed to be white in color and soluble in polar aprotic solvents such as DMAc, DMF, HMPA, and NMP, whereas the polymers with m-phenylene units in backbone were also soluble in common organic solvents such as acetone, chloroform, and THE All the materials showed excellent thermal stability up to 300° C in air without any weight loss, although initial weight losses of 5 and 10% were observed in the temperature ranges of 362-372° C and 376-384° C, respectively [350]. 

The second method is based on the use of polyimides with lower glass transition temperatures that can be melt-processed. For example, intrinsically photosensitive preimidized polymers formed by reacting 3,3 4,4 -benzopheno-netetracarboxylic acid dianhydride (BTDA) with methyl-substituted 4,4 -methylenebisbenzeneamine (MDA), blended to epoxy resins, give high strength laminate with copper. Poly(isoimides), which exhibit good melt-flow properties before thermal isomerization to imides, are also used to make flexible circuits. In the last process copper is electroless plated on polyimide film such as Kapton 200H. 

Japan Synthetic Rubber Corporation (JSR) was established for the domestic production of synthetic rubber in 1957, but entered the diversified businesses that utilize rubber raw materials fi-om around 1969. The first step was the development of a photosensitive material for semiconductors, and in search of new business, the LCD applications began to surface. Then the discussion started if it could be that new materials need to be synthesized for digital clocks, for example. LCDs at the time were TN-type monochrome displays, in which the alignment layer had to be heated to a high baking temperature of over 300 °C in order to transform the wholly aromatic polyamic acid precursor into polyimide. 

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