Development of a Multistep SiO2 Plasma Etching Process in a Minibatch Reactor Using Response‐Surface Methodology

Abstract

A multistep process to etch SiO2 uniformly and selectively over silicon has been developed with a Drytek 202 minibatch, parallel plate reactor using experimental design and response-surface methodology. Glow discharges, formed at a radio frequency of 13.56 MHz with mixtures of C2Fs and CHF~ with He in the first process step but without He in the second process step, were used to achieve etch rates of -2500 and 1750 A/min for a deposited, doped oxide in the first and second steps, respectively. Etch uniformities are < _+ 5% within a wafer for both steps and < _+ 8 and < _+ 10% across the reactor for the first and second steps, respectively. The etch rate of masked single crystal silicon (>95% surface coverage) in the second step is -300 A/min, so that selectivity of etch in this step is >5:1. To minimize reactor cleaning and to insure process uniformity and repeatability, the process is completed with a brief 02 plasma cleaning step after the etching of each batch of wafers. Plots and contour maps of etch rates and SiO2 etch uniformity in the regions about optimized parameter settings which were derived from response-surface models indicate that these settings represent positions of high process stability. ) unless CC License in place (see abstract). ecsdl.org/site/terms_use address. Redistribution subject to ECS terms of use (see 132.174.255.116 Downloaded on 2015-03-15 to IP ) unless CC License in place (see abstract). ecsdl.org/site/terms_use address. Redistribution subject to ECS terms of use (see 132.174.255.116 Downloaded on 2015-03-15 to IP

Predicting instrumental mass fractionation (IMF) of stable isotope SIMS analyses by response surface methodology (RSM) [Dataset]

“…4 This has focused an intense research on the instrumental and compositional factors influencing IMF, the so-called "matrix effect". Eiler et al reported correlations of IMF with the ion sputtering rate and the atomic mass unit of the network-modifying cations in 18 O/ 16 O of target silicates, phosphates and glasses. 5 7 Vielzeuf et al proposed a mathematical script for bias prediction of 18 O/ 16 O analyses as a function of garnet composition using Matlab (The MathWorks, Inc.).…”

“…Eiler et al reported correlations of IMF with the ion sputtering rate and the atomic mass unit of the network-modifying cations in 18 O/ 16 O of target silicates, phosphates and glasses. 5 7 Vielzeuf et al proposed a mathematical script for bias prediction of 18 O/ 16 O analyses as a function of garnet composition using Matlab (The MathWorks, Inc.). 8 Kita et al reported the influence of X-Y mount position and sample topography on IMF using 18 O/ 16 O zircon analyses.…”

“…5 7 Vielzeuf et al proposed a mathematical script for bias prediction of 18 O/ 16 O analyses as a function of garnet composition using Matlab (The MathWorks, Inc.). 8 Kita et al reported the influence of X-Y mount position and sample topography on IMF using 18 O/ 16 O zircon analyses. 9 Page et al fitted linear regressions of IMF versus the composition and molar volume in 18 O/ 16 O analyses of 25 garnet standards.…”

“…8 Kita et al reported the influence of X-Y mount position and sample topography on IMF using 18 O/ 16 O zircon analyses. 9 Page et al fitted linear regressions of IMF versus the composition and molar volume in 18 O/ 16 O analyses of 25 garnet standards. 10 Rollion-Bard and Marin-Carbonne correlated IMF with Mg, Fe and Mn content in 18 O/ 16 O measurements of the calcite-siderite-magnesite solid-solution series.…”

“…Instrumental mass fractionation (IMF) of isotopic SIMS analyses (Cameca 1280HR, CRPG Nancy) was predicted by response surface methodology (RSM) for 18 O/ 16 O determinations of plagioclase, K-feldspar, and quartz. The three predictive response surface models combined instrumental and compositional inputs.…”