PACOR: Practical control-layer routing flow with length-matching constraint for flow-based microfluidic biochips

In flow-based microfluidic biochips, microvalves on the control layer need to be connected to control pins via control channels. In application-specific and portable microfluidic devices, critical microvalves need to switch at the same time for correct functionality. Those microvalves are required to have equal or similar channel lengths to the control pin, so that the control signal can reach them simultaneously. This paper presents a practical control-layer routing flow (PACOR) considering the critical length-matching constraint. Major features of PACOR include: (1) effective candidate Steiner tree construction and selection methods for multiple microvalves based on the deferred-merge embedding (DME) algorithm and maximum weight clique problem (MWCP) formulation, (2) minimum cost flow-based formulation for simultaneous escape routing for improved routability, and (3) minimum-length bounded routing method to detour paths for length matching. Computational simulation results show effectiveness and efficiency of PACOR with promising matching results and 100% routing completion rate.