Browsing by Author "Tu, Hung-En"

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Effect of Porogen Incorporation on Pore Morphology of Low-k SiCxNy Films Prepared Using PECVD
(2015-01-01)
Tu, Hung-En
;
Su, Chun-Jen
;
Jeng, U-Ser
;
Leu, Jihperng
;
材料科學與工程學系
Low-k porous SiCxNy films were prepared through plasma-enhanced chemical vapor deposition, using 1,3,5-trimethyl-1,3,5-trivinylcyclotrisilazane (VSZ) as the matrix precursor and epoxycyclohexane (ECH) as a porogen. The effects of porogen loading and deposition temperature on porogen incorporation, pore morphology, and the properties of porous SiCxNy films were examined. In addition, the impact of film shrinkage and the corresponding nanopore structures after annealing were studied. The porosity of films deposited at 100 degrees C increased from 1.8% to 19.8% when ECH loading increased to 30%, above which the porosity remained nearly constant because of high film shrinkage. The pore size decreased slightly from 4.1 to 3.7 nm when ECH loading increased to 30%, above which the pores became larger and were broadly distributed. By contrast, increasing deposition temperature at 20% ECH loading decreased porogen incorporation and increased film density. The porosities and pore size of films decreased, respectively, when the deposition temperature increased. A short-range ordering of pores was observed only at low deposition temperatures because the N-Si-C cross-linked structures and organic phase were present. Optimized processing parameters facilitated the fabrication of low-k porous SiCxNy films exhibiting 19.8% porosity, 3.7-nm pores, a k value of 3.18, and an elastic modulus of 7.7 GPa. (C) The Author(s) 2014. Published by ECS. All rights reserved.
Effect of surfactants on the porogen size in the low-k methylsilsesquioxane/polystyrene hybrid films
(2012-11-01)
Chen, Yu-Han
;
Tu, Hung-En
;
Leu, Jihperng
;
材料科學與工程學系
;
Department of Materials Science and Engineering
An anionic surfactant, sodium dodecylbenzenesulfonate (NaDBS) and a cationic surfactant, domiphen bromide (DB) were used to modify the surface potential of polystyrene (PS) porogen in a post-integration porogen removal scheme. The effect of surfactant modification on the porogen and pore size in the low-k methylsilsesquioxane (MSQ)/PS hybrid films at 10 wt% PS loading, under a slow curing rate, was studied by grazing incidence small-angle X-ray scattering, viscosity measurement, and Fourier-transform infrared analysis. For PS porogen without modification, the porogen aggregated and its size increased from 10.0 to 16.5 nm at different rates, up to 200 degrees C, depending on the porogen diffusivity and steric hindrance by the successively cross-linked MSQ matrix at T >= T-g. In contrast, the NaDBS- and DB-modified porogens with higher surface potential impede their aggregation within the cross-linking MSQ matrix, resulting in a smaller porogen size, by electrostatic repulsion and increased viscosity due to electroviscous effect. Also, the columbic attraction between Si-OH groups of MSQ matrix and the positively charged, DB-modified PS, restrains the PS porogen, thus reduces its aggregation during cure step, leading to a small porogen size and tight distribution (8.7 +/- 2 nm) at 200 degrees C and later a similar pore size after porogen removal at 400 degrees C. (C) 2012 Elsevier Inc. All rights reserved.
Low-k SiCxNy Films Prepared by Plasma-Enhanced Chemical Vapor Deposition Using 1,3,5-trimethyl-1,3,5-trivinylcyclotrisilazane Precursor
(2012)
Tu, Hung-En
;
Chen, Yu-Han
;
Leu, Jihperng
;
材料科學與工程學系
;
Department of Materials Science and Engineering
Low-k silicon carbonitride (SiCxNy) films with k of 3.6-4.6 were prepared by radio frequency plasma-enhanced chemical vapor deposition at 25 to 400 degrees C under low power density of 0.15 W/cm(3), using a single source precursor, 1, 3, 5-trimethyl-1,3,5-trivinylcyclotrisilazane (VSZ), and Ar. At lower deposition temperatures (<= 200 degrees C), most cyclic VSZ structures were preserved in the SiCxNy films, resulting in a lower density (1.60-1.76 g/cm(3)), a lower dielectric constant (k similar to 3.6-3.9) and a fairly good elastic modulus of 22.0-25.0 GPa. When the deposition temperature was raised to 400 degrees C, the cyclic N-Si-N linkages were reformed to a dense Si-N structure, with the desorption of CHx bonds, resulting in higher density (2.0 g/cm(3)), a dielectric constant of 4.6, and an excellent elastic modulus of 65.2 GPa. The leakage current density of SiCxNy films was reduced from 1.5x10(-6) to 4.0x10(-8) A/cm(2) at 1 MV/cm, upon increasing the deposition temperature from 25 degrees C to 400 degrees C. The conduction mechanism of the SiCxNy films, except the film deposited at 400 degrees C and tested under higher electric field, exhibited Schottky emission due to few charged defects by using a cyclic VSZ precursor and a lower plasma power density of 0.15 W/cm(3). (C) 2012 The Electrochemical Society. [DOI: 10.1149/2.085205jes] All rights reserved.
Pore morphology of low-k SiCxNy films prepared with a cyclic silazane precursor using plasma-enhanced chemical vapor deposition
(2015-09-01)
Tu, Hung-En
;
Su, Chun-Jen
;
Jeng, U-Ser
;
Leu, Jihperng
;
材料科學與工程學系
Low-k SiCxNy films were prepared using radio-frequency plasma-enhanced chemical vapor deposition (PECVD), with only 1,3,5-trimethyl-1,3,5-trivinylcyclotrisilazane (VSZ) as the precursor; VSZ has cyclic Si-N-Si linkages and three pendent vinyl groups. At lower PECVD temperatures, SiCxNy films possess relatively low film densities, indicating the existence of a loose structure or voidswithin the cross-linked matrix structure. The poremorphology of SiCxNy films deposited at distinct temperatures were examined using grazing-incidence small-angle X-ray scattering, while the chemical bondings and structural information were analyzed using Fourier-transform infrared spectroscopy. At 100 degrees C, SiCxNy films without porogen displaying 4.9 nm pores and a mean pore spacing of 30.1nmgenerated low-density films because Si-(CH2)(n)-Si and/or Si-(CH2)(n)-CH3 could be incorporated free volume into the N-Si-C cross-linked structure under plasma deposition. At 300 degrees C, the N-Si-C cross-linked structure and the some organic phase were disrupted and transformed into a denser structure, reducing pore size (3.5 nm) and losing pore correlation. Thus, low deposition temperatures facilitate the formation of large pores and the ordering of the pores. Post annealing converted the 100 and 300 degrees C as-deposited SiCxNy films into loose and dense structures, respectively, and maintained slightly reduced pore size and pore correlation in the annealed films. (C) 2015 Elsevier B.V. All rights reserved.