ISR News Story
Micro-Knife-Edge Techniques for Sealing of Microfluidic Systems (ISR IP)
ISR intellectual property available to license
U.S. Patent: 7,375,404
The micro-knife-edge technique allows a microfluidic system (channels, reservoirs and electrodes on a patterned substrate) to be clamped in a leak-tight, water-level "packaging" with fluid inlets and outlets and electrical connections. In conventional approaches, one would seal the fluidic network (except for peripheral fluidic inputs and outputs) either using a permanent bonding on a top layer over the microfluidic channels or using a compressible gasket of some sort. The former has drawbacks in that it cannot be disassembled. The latter has drawbacks in that sealing is not robust, because it is difficult to achieve enough deformation force at all points surrounding the microfluidic channels.
The addition of micro-knife-edges to the wafer design, however, provides localized force on the gasket material close to the fluid flow path and creates a much better seal. A similar "knife-edge" seal is used at a macro-scale in vacuum systems, where a metal gasket is compressed by sharp edges on a flange to seal a vacuum chamber. The scope of the invention is for sealing of microfluidic devices when wafer-level packaging (i.e., allowing a wafer to be dropped into a packaging device immediately after processing with all fluid and electrical connections pre-set) is desired. Because of the small size of the microchannels, nonuniformities and bowing in the packaging can easily lead to leakage. However, the additional force applied to the gasket by the micro-knife-edge allows the channels to seal adequately for fluid flow to occur.
For more information
ISR-IP-Ghodssi ISR-IP-Rubloff ISR-IP-nano ISR-IP-MEMS
June 22, 2007