Abstract: A semiconductor device for producing a movable section by using the sacrifice etching technique, wherein in order to prevent the sticking of the movable section during the sacrifice layer etching process, the movable section is formed with a reinforcing layer before the sacrifice layer etching process to temporarily increase the rigidity of the movable section, the reinforcing layer being removed after completion of the sacrifice layer etching process. The semiconductor device solves the problem of sticking of the movable section without increasing the rigidity of the movable section more than necessary, and is high in yield.

Abstract: An S/N ratio of an output of a semiconductor pressure sensor is improved, the sensor being of an electrostatic capacitance type pressure sensor for generating an output based upon a ratio between capacitances of a pressure sensitive capacitance element and a reference capacitance element. This semiconductor pressure sensor has: a pressure sensitive capacitance element having an electrostatic capacitance Cs changing with a pressure to be detected; a reference capacitance element having an electrostatic capacitance Cr not changing with the pressure; and a unit for detecting the pressure by outputting a signal corresponding to a ratio between the capacitances Cs and Cr, wherein an initial value Cr0 of the capacitance Cr and an initial value Cs0 of the capacitance Cs are defined by 1.2<Cr0/Cs0<1.8. The Cr0/Cs0 ratio is adjusted by changing the electrode area or the like of both the elements.