Direct Patterning of Poly(ether ether sulfone) Using a Cross-linker and a Photoacid Generator

Abstract

A negative-type photosensitive poly(ether ether sulfone) (PSPEES) based on a commercially available engineering plastic poly (oxybiphenyl-4,4 0 -diyloxy-1,4-phenylenesulfonyl-1,4-phenylene) (PEES), a cross-linker 4,4 0 -methylenebis[2,6-bis(methoxymethyl)phenol] (MBMP) having good compatibility with PEES, and diphenylidonium 9,10-dimethoxyanthracene-2-sulfonate (DIAS) as a photoacid generator (PAG) has been developed. The resist consisting of PEES (85 wt %), MBMP (10 wt %) and DIAS (5 wt %) showed a high sensitivity (D 0:5 ) of 21 mJ/cm 2 and a contrast ( 0:5 ) of 2.1 when it was exposed to i-line (365 nm wavelength light), post-exposure baked (PEB) at 170 C for 3 min, and developed with N,Ndimethylacetamide (DMAc) at room temperature. A fine negative-image featuring 4 mm line-and-space pattern was obtained on the film. Thus, this photolithographic system has a highly potential to be utilized in the industry for next generation, because most of engineering plastics having aromatic ring are available as matrix polymers, and this process is not necessary high thermal curing treatment after development.KEY WORDS: Photosensitive Polymer / Photoacid Generator / Poly(ether ether sulfone) / Cross-linker / High-performance engineering plastics such as polyimides (PIs), polybenzoxazoles (PBOs), poly(ether ether sulfone)s (PEESs), poly(phenylene ether)s (PPEs), and poly(ether ether keton)s (PEEKs) are continuously receiving considerable attention for their potential application in automobile, electronics, optical devices and related markets. Particularly, photosensitive polyimides (PSPIs) and polybenzoxazoles (PSPBOs) are widely used as stress buffer and insulation layers of multichip package in micro-electronics field, because they possess excellent thermal stability and mechanical properties, and reasonably low dielectric constant.1-3 As PIs and PBOs are generally not soluble in organic solvents, poly(amic acid)s (PAAs) and poly(o-hydroxy amide)s are used as PI and PBO precursors, respectively, and require an extremely high temperature about 350 C to convert into corresponding PIs and PBOs. This high-temperature process is not applicable to electronic applications because the thickness of silicon wafers is less than 100 mm, and thus the less thermal stress is required. Therefore, we have reported a series of low temperature cyclization methods for PSPIs and PSPBOs to produce more useful applications in the micro-electronics industry. [3][4][5][6][7] It is also important to develop a photosensitive and thermally stable polymer (PSTSP) which does not require high thermal curing treatment.In previous papers, we reported a negative-type PSPI based on PAA, a cross-linker 4,4 0 -methylenebis[2,6-bis(hydroxylmethyl)]phenol (MBHP), and (5-propylsulfonyl oxyimino-5H-thiophene-2-ylidene)-2-(methylphenyl)acetonitrile (PTMA) as a PAG.8,9 A negative-type photosensitive polymer based on poly(naphthylene ether), PTMA, and hexa(methoxymethyl)-melamine as a cross-linker was also reported. 10 These findings prompted us to develop a PST...

Polystyrenes containing flexible alkylsulfonated side chains as a proton exchange membrane for fuel cell application

“…As PBOS x -r-PSBOS y was soluble in water, the cross-linked PBOS x -r-PSBOS y was prepared by the electrophilic substitution reaction between the aromatic rings of PBOS x -r-PSBOS y and the carbocation formed from MBHP as the crosslinker in the presence of methanesulfonic acid (Scheme 3). [35][36][37] The cross-linked PBOS x -r-PSBOS y membrane was prepared as follows: a DMSO solution of PBOS x -r-PSBOS y , 5 wt% of MBHP and a catalytic amount of methanesulfonic acid was cast onto a glass plate. The film was dried at 120 C for 1 h, and 80 C for 20 h in an ambient atmosphere, and the obtained membrane was then immersed in water.…”

Crosslinked copolymer with low dielectric constant and dissipation factor based on poly(2,6‐Dimethylphenol‐co−2,6‐Diphenylphenol) and a crosslinker

“…Methanesulfonic acid was purchased from Aldrich. 4,4′‐Methylenebis[2,6‐ bis (methoxymethyl)] phenol (MBMP), 4,4′‐methylenebis[2,6‐ bis (hydroxymethyl)] phenol (MBHP) and 2,4‐dimethyl‐6‐(methoxymethyl)phenol (DMMP) were prepared according to previous reports, respectively. Poly(2,6‐DMP) was synthesized according to the previous report .…”

“…In this study, we prepared a crosslinked poly(2,6‐DMP(95 mol %)‐ co −2,6‐DPP(5 mol %)) in two steps; poly(2,6‐DMP 95 ‐ co −2,6‐DPP 5 ) was prepared by the oxidative coupling polymerization using a toluene/water heterogeneous system, followed by the reaction of the poly(2,6‐DMP 95 ‐ co −2,6‐DPP 5 ) with 4,4′‐methylenebis[2,6‐ bis (methoxymethyl)] phenol (MBMP) as the crosslinking agent. The MBMP has been used with aromatic polymers and provides the desired balance of flexibility, exterior durability, chemical resistance, and film toughness . The crosslinked poly(2,6‐DMP 95 ‐ co −2,6‐DPP 5 ) had the excellent ε′ of 2.6 and tan δ of 0.004 at 10 GHz.…”

Direct synthesis of functional novolacs and their polymer reactions

“…[34][35][36][37][38][39][40][41][42][43][44][45][46] We have already reported the synthesis of reactive novolacs having a variety of functional groups such as formyl, 31 acetyl 32 and hydroxymethyl groups. 33 The development of such novel reactive novolacs can lead to novolacs finding significantly increased applications.…”