Polyaddition reactions of N-hydroxy maleopimarimide with divinyl ether compounds were carried out to give novel polymers with ester acetal linkages in the main chain. The polymers have good solubility in common organic solvents and relatively high Tg temperatures. The number-average molecular weights of the polymers range from 4000 to 5500, with Mw/Mn of 1.7–2.3. The thermal decomposition temperatures of the polymers are above 220 °C. The film of the obtained polymers showed excellent transparency to UV light above 230 nm. The ester acetal linkage of the polymer chain can be cleaved in the presence of strong acid under mild heating. Making use of the high acidolytic activity of the polymers, positive-tone chemically amplified i-line photoresists can be formed from them and 2,1-diazonaphthoquinone-4-sulfonate, in which the well known photoactive compound can also function as a photoacid generator. The photolithographic performance of the photoresists was evaluated using an i-line exposure system with high photosensitivity and resolution.
Li Hu,Zhou Zhen,Liu Jingcheng,Xu Wenjia,Liu Ren,Liu Xiaoya
Positive chemically amplified molecular glass with pendant t -butyloxy carbonyl ( t -BOC) groups based on β-cyclodextrin (β-CD) was prepared. The β-CD derivatives were obtained from the reaction of β-CD and di- tert -butyl dicarbonate (DBDC) in the presence of 4-dimethylaminopyridine, and the protecting ratio was controlled using various feed amounts of DBDC. Fourier-transform infrared spectroscopy and proton nuclear magnetic resonance were employed to characterize the chemical structure, indicating that the synthesis was successful. Thermal behavior was characterized by thermogravimetric analysis; the results showed that the initial thermal decomposition temperature occurred at approximately 160 °C, which could satisfy the lithography process. Ultraviolet–visible spectrophotometer indicated that the t -BOC-protected β-CD derivatives had low absorbance at 365 nm wavelength. Additionally, X-ray diffraction analysis results showed that the β-CD derivatives had amorphous form, and exhibited excellent film-forming property. The photoresists consisting of different t -BOC protecting groups showed high sensitivity when exposed to 365 nm light and post-baked at 105 °C for 90 s, followed by developing in 2.38 wt% aqueous tetramethylammonium hydroxide solution at room temperature. An enhanced line and space positive patterns with 1 μm resolution were delineated according to digital microscope.
Molecular glass resist has been considered as one of the best choices for a new generation of lithography. In this work, a new type of photoactive compound was obtained by the esterification of tannic acid with 2-diazo-1-naphthoquinone-4-sulfonyl chloride(2,1,4-DNQ-Cl) and ditertbutyl dicarbonate. The new obtained compound possessed both a photosensitive group of diazonaphthoquinone sulfonate(2,1,4-DNQ) and a group of acidolytic protection. Upon the irradiation of the compound under 365 nm light, the former group was photolyzed and converted into indene carboxylic acid along with a small amount of sulfonic acid, which could lead to the deprotection of the latter group. As a result, a novel i-line molecular glass photoresist was formed with the chemical modification of tannic acid. The experimental results show that the modificated compound had a fair solubility in many organic solvents. The lithographic performance of the resist was evaluated on an i-line exposure system with high photosensitivity and resolution as well.
Li Hu,Zhou Zhen,Liu Jingcheng,Zheng Xiangfei,Xu Wenjia,Ji Changwei,Shi Weidong,Liu Ren,Liu Xiaoya
Hexakis(4-formylphenoxy) cyclotriphosphazene (HAPCP), substitution reaction product of hexachlorotriphosphazene (HCTP) with p-hydroxybenzaldehyde, was reduced by sodium borohydride to afford hexakis[4-(hydroxymethyl) phenoxyl] cyclotriphosphazene (HHPCP). The hydroxyl group of this compound was then protected by the reaction with di-tert-butyl dicarbonate ester (DBDC) in the presence of 4-dimethylaminopyridine (DMAP) as catalyst to give t-butyloxy carbonyl (tBOC) protected HHPCP. Fourier-transform infrared spectroscopy (FT-IR) and proton nuclear magnetic resonance ( 1 H NMR) were employed to characterize the chemical structure, indicating that the synthesis was successful. Thermal behavior was characterized by thermogravimetric analysis (TGA), the results showed that the initial thermal decomposition temperature occurred at approximately 170 °C, X-ray diffraction analysis (XRD) results showed that the tBOC protected HHPCP derivatives had amorphous form, and performed excellent film-forming property. Upon irradiation to 365 nm exposure, the photoacid generated proton H + , which can catalyze the deprotection of acid labile tBOC group. This type of novel molecular glass photoresist based on hexachlorotriphosphazene showed high sensitivity, making it possible to fabricate 1 μm line and space pattern under i-line exposure.