SBIR Phase I: MEMS Heat Dissipation Foundation for High Performance Microelectronic Cooling

This Small Business Innovation Research Phase I project involves the design, fabrication and preliminary testing of a micro-machined, horizontal and vertical heat pipe array to create a sealed, recirculating, "heat dissipation fountain" (HDF) for low cost, high performance microelectronic cooling. Based on this technique, localized, substrate bonding technology, a single-crystal (SC) silicon end plates with micro-machined channels that will sandwich multiple layers of interconnected, porous silicon substrates. The three technical innovations are proposed for this project are (1) the development of a method to assemble a 3-D meso-structure by bonding several substrates together (e.g. SC silicon to porous silicon); (2) a meso-scale heat dissipation device from an appropriately scaled, stacked substrate structure; and (3) in-situ, hermetic sealing of a working fluid within the porous structure. These technical innovations are driven by basic research into techniques to decrease the surface temperature necessary for fluid superheat to initiate nucleate boiling and to raise the critical heat flux value for the system. From an engineering aspect, this will lead to an understanding of design parameters and tradeoffs associated with micro-scale two-phase heat transfer mechanisms. Commercial IC-grade SC silicon can cost less than $10 per wafer than commercial supplier of porous silicon. The commercial motivation behind the development of this technology are (1) there is an immediate need for low cost, lightweight, efficient, cooling of microelectronic devices; (2) two-phased cooling allows for cooling of next generation microprocessors with heat fluxes exceeding 100 W/cm2; and (3) stacked bonding allows for scaling of the heat exchanger with changes in microprocessor heat flux