A method of manufacturing a sensor body for a semiconductor sensor by etching a semiconductor substrate, the sensor body including a weight portion disposed in a central portion thereof, a cylindrical support portion disposed in an outer peripheral portion thereof, and a diaphragm portion disposed between the weight portion and the support portion, the method comprising:
- forming an insulating layer on one surface of the semiconductor substrate;
- coating the insulating layer with a photosensitive resist, thereby forming a first unphotosensitized resist layer;
- irradiating ultraviolet light onto the first unphotosensitized resist layer through a photomask and then developing the irradiated first unphotosensitized resist layer, thereby forming on the one surface of the semiconductor substrate a first resist layer having a first etching opening of a predetermined shape, the first resist layer covering a portion where the support portion is to be formed;
- etching the insulating layer through the first etching opening to remove a portion of the insulating layer that corresponds to the first etching opening, thereby forming a second etching opening in the insulating layer;
- removing the first resist layer and then applying anisotropic etching to the semiconductor substrate through the second etching opening, thereby forming a concave portion in the semiconductor substrate;
- forming a wall surface insulating film on an inner wall surface of the concave portion;
- coating the wall surface insulating film and the insulating layer continuous with the wall surface insulating film with a photosensitive resist, thereby forming a second unphotosensitized resist layer;
- irradiating ultraviolet light onto the second unphotosensitized resist layer through a photomask and then developing the irradiated second unphotosensitized resist layer, thereby forming a second resist layer of a predetermined shape and a third resist layer, the second resist layer being disposed on a central location of the concave portion, having a smaller area than an area of a bottom surface of the concave portion, and covering a portion where the weight portion is to be formed, the third resist layer covering a portion located around the concave portion, where the support portion is to be formed, the second and third resist layers defining a third etching opening therebetween;
- etching the wall surface insulating film through the third etching opening, thereby forming a fourth annular etching opening in the wall surface insulating film;
- and
- removing the second and third resist layers and then applying anisotropic etching to the semiconductor substrate through the fourth etching opening, thereby forming an annular concave portion in a portion of the semiconductor substrate located on a bottom of the concave portion, wherein the diaphragm portion is defined by a portion of the semiconductor substrate corresponding to a bottom surface of the annular concave portion, and the weight portion is defined by the portion of the semiconductor substrate that is left on a central location of the annular concave portion.