Browsing by Author "Che, Mu-Lung"

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Moisture uptake and dielectric property of methylsilsesquioxane/high-temperature porogen hybrids and porous low-k films
(2011-12-01)
Che, Mu-Lung
;
Teng, Jun-Yuan
;
Lai, Po-Cheng
;
Leu, Jihperng
;
材料科學與工程學系
Two high-temperature pore generators (porogens) have been used to study the effect of porogen structure on moisture uptake and k-value in methylsilsesquioxane/porogen hybrid films and their corresponding porous films in a postintegration porogen removal scheme. Poly(styrene-b-4-vinylpyridine) containing di-block structure and pyridine polar group leads to higher moisture uptake and k-value in the hybrid films as compared to poly(styrene-block-butadiene-block-styrene) with symmetrical structure and nonpolar groups. Moreover, the moisture uptake behavior in both as-prepared hybrid films is in physical sorption mode based on their reversible adsorption-desorption curve measured by quartz crystal microbalance. After porogen removal, the k-values of porous films are favorably not influenced by porogen structures, and their moisture uptake is as low as 1.78 wt% even at 40 vol.% porosity. However, based on the simulation of the modified-Rayleigh model, the porous films are found to possess 0.4 vol.% chemisorbed moisture on the pore surface, resulting in 17-23% deviation from the ideal k-values.
The Mechanical Property, Microstructure, and Pore Geometry of a Methyltrimethoxysilane Modified Silica Zeolite (MSZ) Film
(2012)
Che, Mu-Lung
;
Chuang, Shindy
;
Leu, Jihperng
;
材料科學與工程學系
;
Department of Materials Science and Engineering
A methyltrimethoxysilane (MTMS) modified silica zeolite (MSZ) film has been prepared using a high ratio of MTMS/tetraethyl orthosilicate (TEOS). This study investigated the effect of MTMS addition on the low-k matrix structure, elastic modulus, and pore geometry. High MTMS loading reduced the k-value of MSZ film down to 2.0, but yielded a lower elastic modulus, 2.7 GPa. Based on grazing-incidence small-angle X-ray scattering (GISAXS) 2D pattern analysis, the pore geometry of the MSZ film was found to be small but elliptical (R(in-plane) similar to 3.75 nm; R(out-of-plane) similar to 3.04 nm). The elliptical pore shape was formed by a collapse of film structure at 150-160 degrees C as a result of similar to 32% thickness shrinkage due to the decomposition of tetra-n-propylammonium hydroxide (TPAOH), a structure directing catalyst, and due to a large degree of crosslinking reaction in the silica matrix. Combining GISAXS, (29)Si-NMR, and FT-IR results, we propose that the lower elastic modulus was caused by the incorporation of a large amount of methyl groups from the MTMS precursor and the elliptic pores. (C) 2012 The Electrochemical Society. [DOI: 10.1149/2.074203jes] All rights reserved.
Thermal and mechanical properties of hybrid methylsilsesquioxane/poly(styrene-b-4-vinylpyridine) low-k dielectrics using a late porogen removal scheme
(2010-06-01)
Che, Mu-Lung
;
Huang, Cheng-Ying
;
Choang, Shindy
;
Chen, Yu-Hen
;
Leu, Jihperng
A late porogen removal scheme was used to make low-k materials (k = 2.72 to 2.02) using methyl silsesquioxane (MSQ) and a high-temperature porogen, poly(styrene-b-4-vinylpyridine) (PS-b-P4VP), to circumvent the reliability issues related to as-deposited porous dielectric. Based on the nanoindentation and Fourier transform infrared spectroscopy (FTIR) analysis, the moduli of the hybrid films were found to be higher than their porous forms, and even better than the dense MSQ film, for porogen loading below a critical level (similar to 69.5 vol%). This could be attributed to their enhanced degree of cross-linking in MSQ as evidenced by the network/cage structural ratios. Besides, high-temperature porogen plays different roles during the cross-linking of MSQ depending on its loadings. In this study, with immediate loading at 16.7 vol%, PS-b-P4VP can serve as plasticizer to enhance the degree of cross-linking, but at a large loading >16.7 vol%, it becomes a steric hindrance reducing the degree of cross-linking.