High performance polyimides for applications in microelectronics and flat panel displays

Abstract

Polyimides (PIs) exhibit excellent thermal stability, mechanical, dielectric, and chemical resistance properties due to their heterocyclic imide rings and aromatic rings on the backbone. Due to these advantageous properties, PIs have found diverse applications in industry. Most PIs are insoluble because of the nature of the high chemical resistance. Thus, they are generally used as a soluble precursor polymer, which forms complexes with solvent molecules, and then finally converts to the corresponding polyimides via imidization reaction. This complexation with solvent has caused severe difficulty in the characterization of the precursor polymers. However, significant progress has recently been made on the detailed characterization of PI precursors and their imidization reaction. On the other hand, much research effort has been exerted to reduce the dielectric constant of PIs, as demanded in the microelectronics industry, through chemical modifications, as well as to develop high performance, light-emitting PIs and liquid crystal (LC) alignment layer PIs with both rubbing and rubbing-free processibility, which are desired in the flat-panel display industry. This article reviews this recent research progresses in characterizing PIs and their precursors and in developing low dielectric constant, light-emitting, and LC alignment layer PIs.

Novel Non‐Coplanar and Tertbutyl‐Substituted Polyimides: Solubility, Optical, Thermal and Dielectric Properties

“…It must be emphasized that the good solubility of the PIs in low boiling point solvents is desired for preparing polymer films at relatively low processing temperature, which has application prospects for advanced microelectronics manufacturing, flexible displays, flexible printed circuit board (FPCP) and flexible organic solar cells. [22][23][24][25][26] …”

Preparation of Nanopatterned Polyimide by Imprinting and Curing Phenylethynyl- terminated Imide Oligomer

“…Recently, the nanopatterns have been fabricated on polyimide films to use in various fields, such as microelectric devices [6], biological applications [7] and displays [8], and their application could be further extended to other fields if they can be easily patterned at micro or nanoscale. Aromatic polyimide, Pyralin 2525 (HD Microsystems PI2525), has been imprinting by three approaches; imprint as its uncured soft state and cure it afterwards; imprint another low Tg polymer, then form the pattern on polyimide surface by oxygen reactive ion etching; and direct imprint on polyimide surface at temperature higher than its Tg [9].…”

The effect of phenoxymethyl side groups on the liquid crystal alignment behavior of polystyrene derivatives

“…[1][2][3][4][5][6] The mechanical rubbing of polyimide (PI) surfaces is the most commonly used technique for producing LC alignment layers, 7-21 which can induce stable homogeneous planar LC alignment 19,20 or homeotropic LC alignment. 14,18 The LC alignment properties such as the pretilt angle and electro-optical (E-O) performance on polyimide surfaces are known to be affected by the molecular structure of the polyimide such as the flexibility of the polymer backbone, isomeric structure of the mesogen end groups, spacer length, and spacer conformation in the side chains.…”