Browsing by Author "Liou, HC"

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Study the impact of liner thickness on the 0.18 mu m devices using low dielectric constant hydrogen silsesquioxane as the interlayer dielectric
(2000-12-01)
Lan, JK
;
Wang, YL
;
Wu, YL
;
Liou, HC
;
Wang, JK
The electrical performance of hydrogen silsesquioxane (HSQ) as the interlayer level dielectric (ILD) has been determined by using two-metal-layered test structures to study the impact of oxide liner thickness on the capacitance reduction. In comparison with SiO2, HSQ test structures formed with SiO2 cap and liner or with SiO2 cap only, have 20-27% lower intraline capacitance while 6-16% reduction was observed for fluorosilicate glass (FSG) relative to SiO2. It was found that the capacitance of SiO2/HSQ ILDs did not vary with oxide liner thickness as expected. Similar effects were observed with via resistance measurement. Analysis of the structure shows that wide variation of SiO2/HSQ/SiO2 stack thickness after oxide Chemical Mechanical Polishing (CMP) step changed the expected contribution of liner thickness on the intraline and interlayer capacitance. This thickness variation also has a strong impact on landed/unlanded via resistance. Therefore, a good control of oxide CMP on the ILD stack is needed to reduce the thickness variation of the liner/HSQ/cap ILD stack which in turn will enhance process yields in the 0.18 mum devices. (C) 2000 Elsevier Science B.V. All rights reserved.
X-ray reflectivity and FTIR measurements of N-2 plasma effects on the density profile of hydrogen silsesquioxane thin films
(2001-10-01)
Lee, HJ
;
Lin, EK
;
Wu, WL
;
Fanconi, BM
;
Lan, JK
The density depth profile and chemical bond structure of hydrogen silsesquioxane (HSQ) thin films treated with an N-2 plasma with varying power and exposure time were measured using specular X-ray reflectivity (SXR) and Fourier transform infrared (FTIR) spectroscopy. The SXR data indicated that the density profile of an untreated HSQ film is not uniform. At least four layers with different electron densities were required to fit the SXR data. For HSQ films treated with either increasing plasma power or plasma exposure time, the film roughness increased and a densified layer was observed at the film/air interface. The thickness of the densified layer increased with both plasma power and plasma exposure time. In the FTIR spectra of the plasma-treated films, the intensities of the Si-O peaks due to the network structure and the Si-OH peak due to water absorption increased and the intensities of the Si-H peaks decreased. The FTIR data show that the plasma converts the HSQ structure into a SiO2-like structure and are consistent with the densification observed in the SXR measurements. In general, the HSQ film is more sensitive to increasing plasma power than to increasing plasma exposure time. (C) 2001 The Electrochemical Society.