Selective Chemical Liquid Deposition Process for Mini-Structures and Microsystems

Drexel University, Philadelphia PA

Investigators

Abstract

The objective of this one year project is to demonstrate the feasibility of a novel Selective Chemical Liquid Deposition process (SCLD) that creates 3-D structures with better properties and lower fabrication-induced residual stresses than other deposition and solid freeform fabrication processes. Currently most of the technologies used in fabrication of microstructures and MEMS involve sophisticated and expensive processes, such as photo-lithography, silicon surface machining, and silicon bulk machining. For example, chemical vapor deposition processing is a moderate to high temperature deposition process that introduces defects and residual stresses into the films produced. To overcome CVD shortcomings and to explore new chemical deposition applications and new materials in the fabrication of mini-structures and microsystems, the SCLD Process will integrate chemical liquid deposition research, solid freeform fabrication, systems and control, and mini-structures and microsystems (MSMS) in one automated process. The research plan for developing SCLDP-MSMS investigates the controlled deposition as a room temperature solution or liquid reactant is sprayed from a nozzle, making contact with a hot substrate, resulting in evaporation, decomposition, or reaction. It is expected that the reacted solid products will deposit on the substrate and that by controlling the motion of the nozzle and the spray time, a desired 3-D microstructure can be formed through a layer-by-layer scanning technique. Preliminary work has been done on the conceptual design of the SCLDP-MSMS system, materials selection, and testing. The results are promising. In order to turn this new concept into a reality, the following tasks will be carried out: (1) conduct extensive materials research and testing on the chemical liquid deposition process to find more chemicals which can be used to deposit metals, ceramics, silicon, composite, and carbon structures; (2) design and build a prototype SCLDP-MSMS machine and use the prototype machine to make microstructures; and (3) perform additional experiments on the SCLDP to provide necessary data, boundary conditions and analysis information for process modeling and computer simulation.