Semiconductor pressure sensor, pressure sensor apparatus, electronic equipment, and method of manufacturing semiconductor pressure sensor

A method of manufacturing a semiconductor pressure sensor, comprising the steps of:

• preparing a semiconductor substrate having one main surface Si layer having a first conductivity type and the other main surface Si layer;
• forming a strain gauge resistor having a second conductivity type different from said first conductivity type, on said one main surface Si layer;
• forming diffusion wiring having said second conductivity type and having a higher impurity concentration than said strain gauge resistor, in a region adjacent to said strain gauge resistor in said one main surface Si layer;
• forming a first interlayer insulating film on said one main surface Si layer;
• forming a lower electrode layer on said first interlayer insulating film;
• forming a piezoelectric layer on said lower electrode layer;
• forming an upper electrode layer on said piezoelectric layer;
• forming a second interlayer insulating film on said first interlayer insulating film, said lower electrode layer, said piezoelectric layer, and said upper electrode layer;
• forming contact holes reaching said diffusion wiring, said lower electrode layer, and said upper electrode layer, in said second interlayer insulating film;
• forming metal wiring on said second interlayer insulating film and in said contact holes;
• and
• forming a reference pressure chamber in said other main surface Si layer.