Multi-beam type single-mass block in-plane biaxial acceleration sensor chip and preparation method thereof

Abstract

The present invention discloses a multi-beam type single-mass block in-plane biaxial acceleration sensor chip and a preparation method thereof. The sensor chip adopts an SOI silicon slice to manufacture, and comprises a chip outer frame, a master supporting beam, a connecting beam, a slave supporting beam, sensitive piezoresistive micro-beams, a mass block, metal lead wires and pads. One end of the master supporting beam is fixed to the chip outer frame, and the other end is connected with the connecting beam. The other end of the connecting beam is connected with the slave supporting beam, and the other end of the slave supporting beam is connected with the mass block. The eight sensitive piezoresistive micro-beams in the chip are located in the gaps between the chip outer frame and the connecting beam, every two sensitive piezoresistive micro-beams are distributed at the two sides of the master supporting beam symmetrically, one ends of the sensitive piezoresistive micro-beams are fixed to the chip outer frame, and the other ends are connected with the connecting beam. The piezoresistors on the eight sensitive piezoresistive micro-beams are connected via the metal lead wires andthe sixteen pads and form a Wheastone full-bridge circuit. The sensor chip of the present invention can realize the measurement of the acceleration less than 100g, has an inherent frequency more than40 kHz, and satisfies the high-frequency low-g value acceleration dynamic measurement requirement.

Description

technical field

[0001] The invention belongs to the field of measurement of micromechanical electronic sensors, and in particular relates to a multi-beam type single-mass block in-plane biaxial acceleration sensor chip and a preparation method thereof. Background technique

[0002] With the development of Micro Electro Mechanical Systems (MEMS) technology, acceleration sensors based on different principles have been widely used, such as piezoresistive, capacitive, electromagnetic, piezoelectric, resonator, Fiber optic type and thermocouple type, etc. Acceleration sensors with different sensitivity principles have different advantages and disadvantages. For example, although piezoelectric acceleration sensors have been used maturely, they are limited by their sensitivity principles. Piezoelectric sensors cannot measure static acceleration, and the output charge signal needs subsequent assistance. circuit, it is not easy to realize the integrated design of sensitive chips and...

Examples

Embodiment

[0070] The method for preparing the acceleration sensor chip of the present embodiment comprises the following steps, referring to Figure 6 to Figure 8 :

[0071] Step 1), use the HF solution with a volume concentration of 49% to clean the SOI silicon chip of the N-type (100) crystal plane; the structure of the SOI silicon chip from top to bottom is: The layer 14 and the lower layer of single crystal silicon 15 have a thickness of 10 μm, 1 μm and 304 μm in sequence, wherein the buried silicon dioxide layer 14 separates the upper layer of single crystal silicon 13 from the lower layer of single crystal silicon 15;

[0072] Step 2), then carry out high-temperature oxidation on the SOI silicon wafer, the oxidation temperature is 900-1200 ° C, and form a silicon dioxide layer 10 on the front and back sides of the SOI silicon wafer, and then use a P-varistor plate to oxidize the upper layer single crystal The silicon dioxide layer 10 formed on the surface of the silicon 13 is pho...

technical field

[0001] The invention belongs to the field of measurement of micromechanical electronic sensors, and in particular relates to a multi-beam type single-mass block in-plane biaxial acceleration sensor chip and a preparation method thereof. Background technique

[0002] With the development of Micro Electro Mechanical Systems (MEMS) technology, acceleration sensors based on different principles have been widely used, such as piezoresistive, capacitive, electromagnetic, piezoelectric, resonator, Fiber optic type and thermocouple type, etc. Acceleration sensors with different sensitivity principles have different advantages and disadvantages. For example, although piezoelectric acceleration sensors have been used maturely, they are limited by their sensitivity principles. Piezoelectric sensors cannot measure static acceleration, and the output charge signal needs subsequent assistance. circuit, it is not easy to realize the integrated design of sensitive chips and...

Examples

Embodiment

[0070] The method for preparing the acceleration sensor chip of the present embodiment comprises the following steps, referring to Figure 6 to Figure 8 :

[0071] Step 1), use the HF solution with a volume concentration of 49% to clean the SOI silicon chip of the N-type (100) crystal plane; the structure of the SOI silicon chip from top to bottom is: The layer 14 and the lower layer of single crystal silicon 15 have a thickness of 10 μm, 1 μm and 304 μm in sequence, wherein the buried silicon dioxide layer 14 separates the upper layer of single crystal silicon 13 from the lower layer of single crystal silicon 15;

[0072] Step 2), then carry out high-temperature oxidation on the SOI silicon wafer, the oxidation temperature is 900-1200 ° C, and form a silicon dioxide layer 10 on the front and back sides of the SOI silicon wafer, and then use a P-varistor plate to oxidize the upper layer single crystal The silicon dioxide layer 10 formed on the surface of the silicon 13 is pho...

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