Fabrication of vertical through-holes to realize high throughput cell counting

It is desirable to have high throughput cells counting and sizing for various biomedical applications. We have previously reported a micro-machined multiple-channel Coulter counter device to realize such a requirement at a low cost. To further extend the throughput of the device, a 2-D array needs to be developed, and each microchannel (vertical through-hole) should have an independent fluidic pass. In this paper, we present the process flow to fabricate the vertical through-hole array chip. The whole fabrication process is CMOS (Complementary metal-oxide-semiconductor) compatible. The enhanced throughput and sensitivity have been demonstrated by measuring various sized cells in a buffer solution.