ABSTRACT:A novel positive-tone photosensitive polybenzoxazole for low temperature cyclization has been developed. The matrix polymer (PHA-6F) was prepared from 4,4 0 -(hexafluoroisopropylidene)bis(o-aminophenol) (6FAP) and 4,4 0 -oxybis(benzoyl chloride) (OBBC) by low temperature solution polycondensation, and the photosensitive polymer was formulated with PHA-6F, a dissolution inhibitor 1-{1,1-bis, and a photo-and thermoacid generator (5-propylsulfonyloxyimino-5H-thiophen-2-ylidene)-2-(methylphenyl)acetonitrile (PTMA). The photosensitivity and contrast of the 2.4 mm thick film were 15 mJ/cm 2 and 2.5, respectively. A clear positive polybenzoxazole image featuring 8 mm line-and-space pattern was obtained, when a 2.1 mm-photosensitive film containing PHA-6F, S-DNQ, and PTMA (15:3:2 in weight ratio) was prebaked at 120 C for 5 min, irradiated with 365 nm light (60 mJ/cm 2 ), developed with an 2.38 wt % tetramethylammonium hydroxide (TMAH) solution for 90 s, washed with acetic acid, and cured at 250 C for 10 min.

A novel poly(o-hydroxyamide) (PHA) based photosensitive polymer that exhibits high transparency at 365 nm wavelength (i-line) has been developed. Timedependent density functional theory (TD-DFT) calculations using the B3LYP hybrid functional were performed to predict the transparencies of various hydroxyamides in the i-line region. Based on the calculations, 4,4 0 -sulfonylbis(o-aminophenol) (SAP) was prepared and polymerized with 4,4 0 -oxybis(benzoyl chloride) (OBBC), and the resulting PHA, which is abbreviated as PHA-S, showed a high transparency comparable to that of PHA derived from 4,4 0 -(hexafluoroisopropylidene)bis(o-aminophenol). Positive-type photosensitive PHA was then formulated based on PHA-S with a crosslinker 1,3,5-tris[(2-vinyloxy)ethoxy]benzene (TVEB) and a photoacid generator (5-propylsulfonyloxyimino-5H-thiophen-2-ylidene)-2-(methylphenyl)acetonitrile (PTMA) (17:3:1 in weight ratio), and demonstrated photosensitivity and contrast of 14 mJ/cm 2 and 2.7, respectively, when the resist film was prebaked at 120 8C for 5 min, irradiated by i-line, post exposure baked at 120 8C for 5 min, developed with an 2.38 wt% TMAH solution for 5 s. A clear positive image featuring 10-mm line-and-space was also printed in a film which was exposed to 50 mJ/cm 2 of i-line by contact-printing.

An efficient acid catalyst for the low-temperature solid-phase cyclization of poly(o-hydroxyamide) (PHA) has been found. Thermal cyclization of PHA into poly(benzoxazole) (PBO) proceeded quantitatively at 250 °C in 10 min in the presence of 10 wt % of a photoacitve compound, (5-propylsulfonyloxyimino-5H-thiophen-2-ylidene)-2-(methylphenyl)-acetonitrile (PTMA).

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ABSTRACT:A novel poly(o-hydroxyamide) (PHA) as a precursor of photosensitive polybenzoxazole (PSPBO) that exhibits high transparency at 365 nm wavelength (i-line) has been developed. Time-dependent density functional theory (TD-DFT) calculations using the B3LYP hybrid functional were performed to predict the transparencies of various o-hydroxyamides in the i-line region. Based on these results, 2,2 0 -dimethyl-biphenyl-3,3 0 -dicarboxylic acid chloride was prepared and polymerized with 4,4 0 -(hexafluoroisopropylidene)bis(o-aminophenol). The resulting PHA-3 showed a high transparency (92%, 1:0 Â 10 À3 mol/L in N,N-dimethylacetamide (DMAc)), superior to that of the conventional PHA-1 (83% at the same concentration in DMAc) derived from 4, The thermal and dielectric characteristics of photosensitive polyimide (PSPI) are acceptable for a number of applications in the semiconductor industry, and a wide variety of PSPI has been developed and are made commercially available to meet requirements of different applications, such as inter-level insulation, stress buffer layer, and -ray shielding layers of semiconductor devices.1 PI, however, has numerous imide groups that increase water uptake and dielectric constant.2 Polybenzoxazole (PBO) is known as an super engineering thermoplastics, and its properties are comparable with PI. In addition, the absence of carbonyl group in PBO results in lower water uptake and dielectric constant.2 Thus, the photosensitive polybenzoxazole (PSPBO) is attracting great attention as substitute for conventional PSPI in recent years. 3-12The commercially available PSPBO is based on poly(o-hydroxy amide) (PHA), which is usually prepared by polycondensation of 4,4 0 -(hexafluoroisopropylidene)bis(o-aminophenol) (12) and 4,4 0 -oxybis-(benzoic acid) (8a) using a condensation agent, because of its high transparency at 365 nm wavelength (i-line). 13,14 There is an increasing demand for thicker films for small package to act as a buffer layer andray shielding applications, 15,16 consequently, it is quite important to develop a novel photosensitive polymer with higher transparency for UV lithography. The absorption of PI and PBO in i-line region corresponds to the excitation of electrons such as transitions involving p, s, and n electrons, charge-transfer (CT) electrons, and d and f electrons. Recently, we have demonstrated that the time-dependent density functional theory (TD-DFT) calculations using the B3LYP hybrid functional with the 6-311++G(d,p) basis set can well reproduce UV spectra in the measurements of model compounds without incorporation of empirical corrections.17 Utilizing this method, the absorption in i-line region of the above mentioned PHA was found to be the CT type transition between the benzoic acid and the o-hydroxyamide rings. Therefore, we designed and prepared a novel transparent PSPBO based on 4,4 0 -sulfonylbis(o-aminophenol) (13) and 4,4 0 -oxybis(benzoyl chloride) (8b) for i-line lithography.18 Introduction of a sulfone group as a substitute for hexafluoroisopropylidene...