Integrated Test Module Design for Microfluidic Large-Scale Integration

Microfluidic large-scale integration (mLSI) is a promising lab-on-a-chip platform for high-throughput bio-applications. Due to the high integration scale and the small feature size, control channels on mLSI chips are prone to blockage and leakage defects, which may lead to faulty behavior of valves and erroneous experimental results. Thus, mLSI chips need to be tested before usage. Current mLSI-tests are mostly performed in a straightforward way by testing each valve individually, which is very time consuming and error prone. As the integration scale of mLSI chips keeps increasing, there is a pressing demand for more efficient test approaches. This work proposes the first built-in-self-test (BIST) method for mLSI with an integrated test module design. Instead of testing individual valves, the proposed method directly tests the control channels and thus greatly improves the test efficiency. Only ${}({n}/{2})$ and $\lceil \log _{2}(n+1)\rceil $ test operations are required to test the blockage and leakage defects, respectively, of $n$ control channels. The proposed test module consumes moderate area overhead and the test method is easy to operate. Neither specialized software nor external pressure sensors are required for carrying out the tests. Experiments show that our test approach is sensitive enough to detect defects that have a feature size as small as 10 $\mu \text{m}$ and that are several centimeters away from the test module.