A novel **dry-etch** technique which does not require resist development has been studied. The new technique enables the diffusion of gaseous HF and water vapor through the exposed resist and the selective etching of the underlying SiO2. Etching is observed to proceed only when the resist is in contact with the SiO2 underneath. The ratio of the etch rate of SiO2 beneath exposed and unexposed resist can be essentially infinity. This very high selectivity was used for etching high resolution SiO2 patterns without development. Variations of etch rate with substrate temperature (100° to 250°C), exposure dose (0−54 J/cm2 for UV, and 0−3.2 mC/cm2 for e-beam at 20 keV) HF vapor flow and resist thickness (1600 to 4000 Å) are presented. The new microlithographic etch process for patterning SiO2 does not require resist development and therefore reduces the three key steps in microlithography—exposure, development, and etching to two. As a result, it eliminates the problems introduced during the development stage such as pinholes and loss of pattern fidelity. The process is capable of resolution down to at least 0.7 μm linewidths in silicon dioxide and in principle can be applied to other materials with volatile reaction products.
This article is difficult to contextualize due to a lack of journal categories. However, given that the article was published in the Journal of Vacuum Science and Technology, it can be inferred that the paper's topic aligns with the journal's focus on materials science and thin-film technology. By studying polysiloxane resist, the paper contributes to the development of resist materials.