Micromachined thermal mass flow sensor and manufacturing method thereof

摘要

The present invention concerns a gas flowmeter comprising: a semiconductor substrate (2) including a cavity (9); an insulating film (7b) formed above said semiconductor substrate (2) so that said cavity (4) is covered with said insulating film (7b); and a heat element (4), temperature measuring resistors (5a-5d) and wiring connection portions (11c-11l) each formed on said insulating film (7b); said heat element (4), said temperature measuring resistors (5a-5d) and said wiring connection portions (11c-11l) each being an impurity-doped polycrystalline silicon semiconductor thin film (23). Said impurity-doped polycrystalline silicon semiconductor thin film (23) provides a resistivity of 8 x 10 -4 ©cm or less.