Pressure sensor of packaging structure and preparation method thereof

The invention discloses a pressure sensor of a packaging structure and a preparation method thereof. A lightly boron-doped region and a heavily boron-doped region are prepared by doping on the front of a silicon wafer. A groove is arranged on the back of the silicon wafer through etching. A silicon pressure film is formed between the bottom of the groove and the lightly boron-doped region. An insulating layer is laid on the front of the silicon wafer. A metal lead is arranged on the top of the insulating layer, and is connected with the lightly boron-doped region and the heavily boron-doped region. Four piezoresistive strips are formed in the lightly boron-doped region. The piezoresistive strips and the metal lead form a Wheatstone full-bridge structure. The front of the silicon wafer is bonded to a piece of front bonding glass through a middle layer. A piece of back bonding glass is bonded to the back of the silicon wafer, and the side, directly facing the silicon pressure film, of the back bonding glass is provided with an air guide hole. The part, directly facing the silicon pressure film, of the front bonding glass is provided with a cavity. The packaging structure of the invention is simple and compact, and highly reliable. The manufacturing process is simple, wafer level packaging can be realized, and low-cost mass production is facilitated.