Patent ID: 7673508

Claim:
A thermal-type fluid flow sensor for measuring an air flow rate flowing through an air intake passage, comprising: a heating resistive element formed on a semiconductor substrate through a first insulating layer; a temperature-measuring resistive element for measuring a temperature of the heating resistive element; upstream and downstream side temperature-measuring resistive elements for detecting the temperature of air on an upstream side and a downstream side of the air heated by the heating resistive element; and an air temperature-measuring resistive element for measuring the air before being heated by the heating resistive element, wherein at least the temperature-measuring resistive element for the heating resistive element is disposed in an upper layer or a lower layer of the heating resistive element, wherein the temperature-measuring resistive elements are disposed in the upper layer or the lower layer of the heating resistive element through a second insulating layer, wherein a film thickness of the second insulating layer disposed between the heating resistive element and the temperature-measuring resistive element for the heating resistive element is approximately 20-500 nm.