The Use of Unsaturated Fluorocarbons for Dielectric Etch Applications

Abstract

Six unsaturated fluorocarbon (UFC) gases as well as a fluorinated ether were examined for dielectric etch and global warming emissions performance and compared to three perfluorocompound (PFC) gases. All of the gases were capable of etch performance comparable to that of a typical C3F8 process, while exhibiting superior global warming emissions performance compared to the PFCs. A low-flow hexafluoro-2-butyne process was found to have a significant emissions benefit, showing a normalized emissions reduction of 88.2% compared to the C3F8 process. Two other C4F6 isomers (hexafluoro-1,3-butadiene and hexafluorocyclobutene) also exhibited reductions greater than 80%, while hexafluoropropene and octafluorocyclopentene exhibited emissions reductions greater than 70% compared to the typical C3F8 process. For the C4F6 isomers, a large portion of the emissions were a result of CHF3 formation with photoresist as the sole source of the hydrogen. An extended 4 min etch with hexafluoro-1,3-butadiene resulted in a deep via with an aspect ratio of 5:1, very high selectivity to photoresist, and no evidence of etch stopping. © 2002 The Electrochemical Society. All rights reserved.

Angular Dependence of Si3N4 Etching in C4F6/CH2F2/O2/Ar Plasmas

“…They successfully observed the angular dependence of the Si 3 N 4 etch rate under practical plasma etching conditions, but the discharge gas, C 4 F 8 , was perfluorocarbon (PFC). PFCs are problematic from an environmental viewpoint because they have long atmospheric lifetimes and high global warming potentials . Unsaturated fluorocarbons like C 4 F 6 have been considered as alternatives to PFCs , .…”

Direct Transformation of Tetrafluoroethylene to Trifluorovinylzinc via sp2 C–F Bond Activation

“…2, 3 In addition, hexafluorobutadiene is the best-performing dry-etching gas with a low global warming potential (GWP), 4 which enables the fabrication of complicated networks of narrow and deep microchannels on silicon substrates for large-scale integration (LSI) chips. 5 Furthermore, the trifluorovinyl group has attracted attention as a potentially interesting fluorinated functional group for the design of drug candidates. 6 α,β,β-Trifluorostyrene derivatives have been synthesized through the palladium-catalyzed cross-coupling of aryl halides with trifluorovinylmetal intermediates (metal = Zn, 7−9 Sn, 10 or B 11 ).…”

Dependence of etch rates of silicon substrates on the use of C4F8 and C4F6 plasmas in the deposition step of the Bosch process

“…[3][4][5][6][7] However, C 4 F 8 ͑octafluorocyclobutane͒ is perfluorocarbon ͑PFC͒, which is strongly problematic from an environmental point of view because of its long atmospheric lifetime, high global warming potential, and strong infrared absorption. [8][9][10] This has become a serious issue for the semiconductor industry because PFCs are used extensively as etchants for silicon and silicon dioxide. [11][12][13][14] In order to reduce PFC emissions, many studies have been carried out to identify environmentally benign alternatives to PFCs, including unsaturated fluorocarbons ͑UFCs͒, such as hexafluoropropene ͑C 3 F 6 , CF 2 v CF-CF 3 ͒, hexafluoro-1,3-butadiene ͑C 4 F 6 , CF 2 v CF-CFv CF 2 ͒, octafluorocyclopentene ͑C 5 F 8 ͒, etc., as well as to determine their etching characteristics.…”