Patent ID: 7332902
Filing Date: 2008-02-19
Classification: B01L,G01N

Abstract:
1. A micro sensor for electrochemically monitoring fluid residue, comprising: a substrate; first, second and third fixed dielectric layers in a stack on said substrate, said third dielectric layer having a top surface that defines a fluid-solid interface for receiving a fluid; a buried micro channel in the second dielectric layer between the first and third dielectric layers; at least one opening through the third dielectric layer to said buried micro channel allowing the fluid at said fluid-solid interface to enter the buried micro-channel; and at least one pair of lower and upper electrodes in the first and third dielectric layers at a fixed separation and spaced a known distance from said at least one opening, said lower and upper electrodes exposed to fluid in the micro channel and configured to receive an ac measurement signal to measure the impedance of the micro channel between the electrodes as a measure of fluid residue in said micro channel at the known distance from the opening.