Takeyoshi Kato

High-Speed Damage-Free Contact Hole Etching Using Dual Shower Head Microwave-Excited High-Density-Plasma Equipment

Dual shower head microwave-excited plasma etching equipment for separating the plasma-excited region from the etching process region has been developed. With the aim of realization of damage-free etching, the carrier activation of boron-doped p+-Si is investigated after plasma irradiation. The damage-free-etching mode in which holes do not deactivate was found. Contact holes are successfully etched using a surface damage-free etching process consisting of high-speed etching mode and surface damage-free etching mode. The damage-free-etching mode consists of low-self-bias condition and a low etching gas flow rate as compared with the high-speed mode. For both modes, the etcher can maintain the process uniformity because the etcher can control self-bias voltages without changing other process parameters.

Adsorption Behavior of Various Fluorocarbon Gases on Silicon Wafer Surface

An analytical technique to clarifying the adsorption behavior of a fluorocarbon gas, which is one of the key steps in reactive ion etching, has been established. In this paper, we focus on the adsorption behavior of fluorocarbon gases to the silicon wafer surface to clarify the etching mechanism in order to realize etching to a high aspect ratio. Each fluorocarbon gas had surface selectivity for SiO2, Si and the photoresist. Each fluorocarbon gas reacted differently at the silicon wafer surface. As a result, the etching mechanism could be clarified using this newly established analytical technique. Therefore, an etching mechanism will be able to be clarified by applying the newly established analytical technique to the fluorocarbon gases expected to be useful for etching of high aspect ratio and further high performance ultra large scale integrated circuit device must be realized.