Manufacture of integrated capacitive transducer

PURPOSE: To obtain a highly reliable reproducible integrated capacitive transducer by forming a diaphragm by thinning a first base material after welding the first base material to a second base material through a connecting layer and forming an orifice network by thinning the second base material, and then, removing the connecting layer below the diaphragm. CONSTITUTION: A connecting layer 16 composed of a silicon oxide is formed on the first surface 14 of a first base material 10 and a protective layer 20 having the same composition and the same thickness as the connecting layer 16 has is formed on the second surface 18 of the material 10. Then the first surface of a second base material 12 is oppositely faced to the connecting layer 16. After the base materials 10 and 12 are welded to each other in a furnace, the second surface 23 of the second base material 12 is etched to a prescribed thickness. Then orifices 24 and several arms 26 are formed by etching the surface of the base material 12 through a mask made of a photosensitive resin and a diaphragm 28 is formed by etching the base material 10 through a mask. After the connecting layer 16 below the diaphragm 28 is removed, contact pads 30 and 32 are formed by vapor-depositing Al metal in a vacuum through masks. Finally, the formed capacitive transducer is housed in a housing.