A water‐developable negative photoresist based on the photocrosslinking of N‐phenylamide groups with reduced environmental impact

Abstract

A water-developable negative photoresist based on the photocrosslinking of N-phenylamide groups was prepared by the copolymerization of 4-styrenesulfonic acid sodium salts (SSS) with N-phenylmethacrylamide (copolymer A) or p-hydroxy-N-phenylmethacrylamide (copolymer B), and its properties such as solubility changes, photochemical reaction, and photoresist characteristics were studied. The copolymer containing a relatively higher amount of SSS units was soluble in water. Solubility changes of the copolymers in the various buffer solutions of pH 4 ϳ 11 and in water upon irradiation were observed by the measurement of insoluble fraction. The copolymers were soluble in water before irradiation, whereas they became insoluble upon irradiation with the UV light of 254 nm. The photochemical reaction of the copolymer studied by the UV and IR absorption spectroscopies indicated that a photoFries rearrangement was favored for copolymer A, whereas a photocrosslinking reaction was predominate for copolymer B. Resist properties of the copolymers were studied by measurement of the normalized thickness and by development of the micropattern. Negative tone images with a resolution of 1 m were obtained with these materials that have a sensitivity (D g 0.5 ) of ϳ 1100 mJ/cm 2 with an aqueous developing process.

Synthesis and properties of a water-soluble thermo-sensitive resin with tertiary amine oxide substituents in the side chain

“…The mechanism of negative working is shown in Scheme 1. Several groups have reported various water-developable materials and their applications, such as base-amplifying copolymers and positive-working photoresist, flexographic printing plates consisting of a photosensitive matrix and the diffusion of unreacted component and positive working heat-sensitive imaging composition [5][6][7][8][9][10][11][12]. In our previous work [13], we have also studied a water developable thermo-sensitive latex film.…”

“…Plenty of research articles about water-soluble or thermo-sensitive resins have been reported [8,[14][15][16][17][18][19][20]. Ramesh and Vasudevan [15] have synthesized new water-soluble epoxy ester for formulating high-performance water-based paints.…”

Fast, multi-responsive microgels based on photo-crosslinkable poly(2-(dimethylamino)ethyl methacrylate)

“…It is a well known method from photolithographic literature, and often used in microsystem technology [11], in which pendant chromophoric groups are attached to the polymer as crosslinkers. However, there are relatively few reports of gels being prepared via photo-crosslinking of water-soluble polymers [9,12,13]. In these reports, water-soluble polymers are used as water-developable photo-resists [13], as absorbents for nonionic surfactants with temperature adjustable adsorption properties [12], and for the preparation of LCST polymer systems [8,[14][15][16].…”

Characterization of acrylic copolymers applied in negative‐type photoresist via a ternary composition diagram

“…Photoresists are widely used for the manufacture of microelectronics, silk screen printings, printed circuit boards, optical disks, color filter resists, and so on. [5][6][7] Typically, a negative-type photoresist consists of polymer binder, photosensitive polyfunctional monomer, photoinitiator, solvents and additives. 8,9 Acrylic monomers used to synthesize the binder contain the desired functional groups, such as benzyl, hydroxyl, carboxyl groups, etc.…”