Patent ID: 7363810

Claim:
A corrosion resistant metal made thermal type mass flow rate sensor comprising: (a) a sensor part comprising i. a corrosion resisting metal substrate having a fluid contacting surface, wherein the corrosion resisting metal substrate comprises an outer peripheral part and a central part, wherein the central part comprises a thin plate that has a thickness that is less than the thickness of the outer peripheral part; ii. a thin film forming a temperature sensor; and iii. a heater mounted on a rear face side of the fluid contacting surface of the corrosion resistant metal substrate; (b) a sensor base equipped with the sensor part installed thereupon to secure hermeticity, and the corrosion resistant metal substrate is fastened hermetically to the sensor base, wherein the thin film comprises i. an insulation film formed on the rear face side of the fluid contacting surface of the corrosion resistant metal substrate; ii. a metal film forming the temperature sensor on the insulation film; iii. the heater formed on the insulation film; and iv. a protection film disposed to cover the insulation film and the metal film.