Applicable to Passat fuel common rail pressure sensor 06E906051K

1. A method for forming a pressure sensor, comprising:

Providing a semiconductor substrate, wherein a first interlayer dielectric layer, a first interlayer dielectric layer and a second interlayer dielectric layer are formed on the semiconductor substrate.

A lower electrode plate in the first interlayer dielectric layer, a first mutual electrode located on the same layer as the lower electrode plate and spaced apart.

Connecting layers;

Forming a sacrificial layer above the lower polar plate;

Forming an upper electrode plate on the first interlayer dielectric layer, the first interconnection layer and the sacrificial layer;

After forming the sacrificial layer and before forming the upper plate, in the first interconnection layer

Forming a connection groove, and filling the connection groove with the upper plate to electrically connect with the first interconnection layer; Or,

After forming the upper electrode plate, connecting grooves are formed in the upper electrode plate and the first interconnection layer, which

Forming a conductive layer connecting the upper electrode plate and the first interconnection layer in the connection groove;

After electrically connecting the upper plate and the first interconnection layer, removing the sacrificial layer to form a cavity.

2. The method for forming a pressure sensor according to claim 1, wherein in the first layer

The method for forming the sacrificial layer on the interlayer dielectric layer comprises the following steps:

Depositing a sacrificial material layer on the first interlayer dielectric layer;

Patterning the sacrificial material layer to form a sacrificial layer.

3. The method for forming the pressure sensor according to claim 2, wherein photolithography and engraving are used.

The sacrificial material layer is patterned by etching process.

4. The method for forming a pressure sensor according to claim 3, wherein the sacrificial layer

The material is amorphous carbon or germanium.

5. The method for forming a pressure sensor according to claim 4, wherein the sacrificial layer

The material is amorphous carbon;

Etching gases used in the process of etching the sacrificial material layer include O2, CO, N2 and Ar;

The parameters in the process of etching the sacrificial material layer are: the flow range of O2 is 18 SCCM ~ 22 SCCM, and the flow rate of CO is 10%.

The flow rate ranges from 90 SCCM to 110 SCCM, the flow rate of N2 ranges from 90 SCCM to 110 SCCM, and the flow rate of Ar.

The range is 90 SCCM ~ 110 SCCM, the pressure range is 90 mtor ~ 110 mtor, and the bias power is

540w～660w。