The　emergence　of　flow-based　microfluidic　biochips　(FBMBs)　has　increased　the　automation　level　of　biochemical　procedures,　and　these　lab-on-a-chip　devices　are　now　being　used　for　enzyme-linked　immunosorbent　assay,　point-of-care　diagnosis,　etc.　As　fabrication　technology　advances,　the　feature　size　of　FBMBs　keeps　shrinking,　thereby　introducing　a　series　of　knotty　challenges　to　the　physical　design　of　FBMBs.　In　particular,　timing-sensitive　bioassays,　such　as　forensic　DNA　typing　and　chromatin　immunoprecipitation,　require　a　highly　accurate　time-control　of　fluids　within　a　limited　completion　time.　However,　existing　work　does　not　consider　the　real-time　requirements　of　these　bioassays.　In　this　paper,　we　formulate　the　first　practical　timing-driven　flow-channel　network　construction　problem　for　FBMBs　and　present　a　performance-driven　placement　and　routing　algorithm　for　solving　this　problem.　Given　the　design　specifications　of　a　biochip　and　its　biochemistry　application,　our　goal　is　to　construct　a　high-quality　flow-channel　network　with　minimized　timing　delay　and　total　cost.　The　experimental　results　on　14　benchmarks　confirm　that　our　algorithm　leads　to　better　timing　behavior　and　lower　chip　cost.