Patent ID: 7752910
Filing Date: 2010-07-13
Classification: G03H

Abstract:
1. A flow rate sensor comprising: a TCR temperature sensing resistor element having a predefined temperature coefficient of resistance (TCR) disposed entirely on a thermally isolated membrane comprising a single silicon nitride layer coated with a thin hydrophobic fluorocarbon layer extending over an open-through-substrate cavity opened through a bottom surface to a top surface of a substrate with said thermally isolated membrane extending over and exposed directly to a hollow space underneath; a heating resistor disposed on said thermally isolated membrane; and said heating resistor and said TCR temperature sensing resistor element are covered by a passivation layer segments with a separation gap to separate a passivation layer segment covering said heating resistor from another passivation layer segment covering said TCR temperature sensing resistor element for thermally isolating said heating resistor from said TCR temperature sensing resistor element.