Fluorocarbon plasma , etching

Figure C2.13.7. Change between polymerizing and etching conditions in a fluorocarbon plasma as detennined by tire fluorine-to-carbon ratio of chemically reactive species and tire bias voltage applied to tire substrate surface [36].

Kay, E., Cobum, J. and Dilks, A. Plasma Chemistry of Fluorocarbons as Related to Plasma Etching and Plasma Polymerization. 94, 1-42 (1980). 

Figure 10, Schematic of the influence of fluorine to carbon ratio and electrode bias on etching versus polymerization processes in fluorocarbon plasmas, (Reproduced with permission from Ref, 40 J...

Plasma Chemistry of Fluorocarbons as Related to Plasma Etching and Plasma Polymerization... 

A brief description of the key plasma diagnostic techniques, which have been especially useful in delineating the gas phase processes in fluorocarbon plasmas, will be given followed by an extensive discussion of plasma etching and polymerization mechanisms. 

Plasma etching is a well-established technology for microchip fabrication, involving the removal of silicon with a beam of fluorine atoms generated by high energy electrical excitation of simple fluorocarbons, notahly carbon tetrafluoridc, chlorotrifluoromethanc. trifluorometh-... 

The etch resistance of poly (butene-1 sulfone) in fluorocarbon-based plasmas can be enhanced by prior treatment of the surface in an oxygen plasma. This pretreatment inhibits or retards the depolymerization reaction that characterizes normal etching in fluorocarbon plasmas, thereby permitting formation of a surface-modified layer which exhibits a substantially reduced etch rate. Pretreating PBS in an oxygen plasma enables it to be used subsequently in selective reactive-ion etch processes involving fluorocarbon plasmas to delineate submicron, anisotropically etched patterns. 

Two fluorocarbon mixtures were used in plasma etching studies. The first consisted of 96%Cp4 and 4%02 while the second contained 50% helium, 49%CP4 and 1%02. 

---