This Small Business Technology Transfer (STTR) Phase I project addresses an enabling technology for fabrication of printed circuit boards and electronic packages. The demand for increased integrated circuit density, performance and reliability while reducing size, weight and cost of electronic modules requires interconnects and packaging to employ lines and spaces that are less than 75 micron in width. Through-mask chemical etching of interconnects isotropically attacks copper under the mask, limiting feature sizes to larger than 75 micron. The proposed innovation, Thermally-Assisted Electro-Etching, combines Faradayic electrochemical etching to generate an anisotropic current distribution through the mask, with a pulsed thermal source to enhance anisotropic etching by selective heating of the exposed copper. Unlike chemical etching, this technology will enable through-mask etching of features 25 - 30 micron in width. The Phase I project will demonstrate this technology through design and build of an apparatus that promotes controlled etching, electrolyte selection, optimization of electrochemical and thermal process parameters, and an economic evaluation of the technology. The anticipated result is a robust, anisotropic, cost-effective through-mask etching process for electronic packaging features below 75 micron. The project team, Faraday, Columbia University and Lockheed-Martin, will set the stage for technology validation and commercialization.
The research project, if successful, will result in higher density, lower cost interconnect applications. The proposed technological innovation is benign and will not adversely impact the environment nor worker safety. Workforce development with Columbia undergraduate and graduate students is anticipated and Faraday routinely provides opportunities for local undergraduate students and high school teachers in conjunction with NSF's REU and RET programs, respectively.
