High Aspect-ratio Oxide Research Articles

Individual Effects of Various Plasma-Related Factors on the High Aspect Ratio Oxide Etching Process at Low-Frequency Bias Power Using an Inductively Coupled Plasma System

Individual Effects of Various Plasma-Related Factors on the High Aspect Ratio Oxide Etching Process at Low-Frequency Bias Power Using an Inductively Coupled Plasma System

Challenges of High Aspect Ratio Oxide Etching

Plasma etch processes for fabrication of contact holes in SiO2 with aspect ratios of 20:1 and beyond were successfully developed. Both etch rates and profile control mechanisms were investigated in depth. Profile bowing, potato-shaped cross-sections, and increase of length to width ratio were identified to be the limiting factors in patterning of high aspect ratio holes in SiO2. Solutions for bow reduction and the handling of length to width ratio were developed and successfully implemented.

Challenges of High Aspect Ratio Oxide Etching

not Available.

Evaluation of Pentafluoroethane and 1,1-Difluoroethane for a Dielectric Etch Application in an Inductively Coupled Plasma Etch Tool

In this work, a combination of two hydrofluorocarbon compounds, pentafluoroethane (FC-125, C2HF5) and 1,1-difluoroethane (FC-152a, CF2H–CH3), was evaluated as a potential replacement for perfluorocompounds in dielectric etch applications. A high aspect ratio oxide via etch was used as the test vehicle for this study, which was conducted in a commercial inductively coupled high density plasma etch tool. Both process and emissions data were collected and compared to those provided by a process utilizing a standard perfluorinated etch chemistry (C2F6). Global warming (CF4, C2F6, CHF3) and hygroscopic gas (HF, SiF4) emissions were characterized using Fourier transform infrared (FTIR) spectroscopy. FC-125/FC-152a was found to produce significant reductions in global warming emissions, on the order of 68 to 76% relative to the reference process. Although etch stopping, caused by a high degree of polymer deposition inside the etched features, was observed, process data otherwise appeared promising for an initial study, with good resist selectivity and etch rates being achieved.