Process for manufacturing improved high-sensitivity low pressure sensor chip

The invention provides a process for manufacturing an improved high-sensitivity low pressure sensor chip. The process is simple, easy in processing and low in production cost. And the sensor chip processed by the process is high in precision and good in stability. So the invention also provides the sensor chip processed by the process. The process is characterized in that: a two-side polished N-type or P-type silicon base is used as a substrate; a layer of composite nonconductive film consisting of SiO2 and Si3N4 ON is grown on each of the front and back sides of the silicon-based substrate; a doped or intrinsic 4 to 6mum nano silicon layer is deposited on each of the composite nonconductive film layer; after an N-type or P-type impurity is filled in the nano silicon layer, a nano silicon piezoresistor is manufactured by a plane photoetching process; concentrated boron or phosphor is doped to lead out an inner lead wire from the nano silicon piezoresistor; the inner lead wire led out is alloyed through AL evaporation and reverse etching; the back of the silicon-based substrate is subjected to micro processing to form a back large film area and a back island; and a pressure-insulating cavity is formed at the bottom of the silicon-based substrate by bonding with silica glass.