Polyimide Containing an Acetal Structure with a Photoacid Generator: A Novel Positive Polyimide Photoresist

Abstract

A main-chain degradable photosensitive polyimide containing an acetal structure which degrades by the action of acid coming from a photoacid generator has been developed. Polyimides 4 were prepared by the reaction of bis(4-aminophenoxy)methane 1 and various tetracarboxylic anhydrides 2, followed by thermal treatment. In the resulting polyimides 4, 4f filmderivedfrom 4,4′-hexafluoroisopropylidenebis(phthalicanhydride)(6FDA)and 1 showedgood solubility in organic solvents and transparency to UV light. The acid-catalysed degradation reaction was confirmed by the model imide compound in the presence of p-toluenesulfonic acid. The system of the polyimide 4f containing 30 wt% of diphenyliodonium 9,10-dimethoxyanthracene-2-sulfonate (DIAS), which is a photoacid generator (PAG) showed a sensitivity of 150 mJ cm−2 with 436 nm light, when it was post-exposure baked at 140°C for 30 min, followed by development with 5% tetramethylammonium hydroxide solution at 45°C.

Recent Development in Photosensitive Polyimide (PSPI)

“…(23)). The system of the PI containing 30 wt % of DIAS as a photo-acid generator showed a sensitivity of 150 mJlcm2 with 436 nm light, when it was postbaked at 140 °C for 30 min, followed by development with 5% TMAH solution at 45 °C [26].…”

The effects of the SiOSi segment presence in BAPP/BPDA polyimide system on morphology and hardness properties for opto-electronic application

“…Thus, these lead to PI being explored extensively and used in the diverse range applications such as dielectric [2,4], encapsulation and packaging [5,6], electrolyte fuels cell [7,8], membrane materials for separation [9], solar cell [10], and photoresist for lithography [11], waveguide [12], and nonlinear optical material, optoelectronic devices [6,13], electroluminescent device [14], electrochromic material [15], fiber optic, composites [16,17]. However, these polymers presented serious processing difficulties due to their extreme glass transition temperature and often insoluble in the most organic solvents in fully imidized form.…”

A Study on Positive Photosensitive Epoxy Resins Using Reaction Development Patterning (RDP)

“…The photoresists have been generally prepared by introducing chromophore units in main chains, on side chains, and/or at the chain ends of polymers. Positive and negative patterns are formed in photolithographic processes using solubility differences of the photoresists to developers between UV exposed and unexposed areas [1][2][3][4][5][6][7][8]. In contrast, Fukushima et al have proposed a new RDP (Reaction Development Pattering) method to easily obtain fine patterns from non-photosensitive plastics such as polyimides, polycarbonates and vinyl polymers that have no chromophore units [9a].…”