Vacuum micro-cavity interferometer chip and manufacturing method therefor, and low-drift optical pressure sensor

WO2026148754A1PCT designated stage Publication Date: 2026-07-16SHANGHAI BAIANTEK SENSING TECH CO LTD +1

Patent Information

Authority / Receiving Office: WO · WO
Patent Type: Applications
Current Assignee / Owner: SHANGHAI BAIANTEK SENSING TECH CO LTD
Filing Date: 2025-04-29
Publication Date: 2026-07-16

AI Technical Summary

Technical Problem

Existing fiber optic pressure sensors are susceptible to electromagnetic interference in high-temperature or radiation environments, and getter contamination and uneven stress can cause measurement drift, making it difficult to meet the requirements of high accuracy and low drift over a wide temperature range.

Method used

A three-layer substrate structure is adopted, including a first substrate, a second substrate and a third substrate, which are connected by silicon-glass-silicon bonding to form a membrane island structure and a getter cavity. The getter cavity and the FP interference cavity are connected by vent holes to reduce getter particle contamination, and the temperature drift is reduced by stress isolation structure.

Benefits of technology

It achieves low drift characteristics and high zero-point stability across the entire temperature range of -55℃ to 125℃, meeting the requirements for high-precision pressure measurement and reducing the temperature coefficient and stress effects of the sensor.

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Figure CN2025092084_16072026_PF_FP_ABST

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Abstract

A vacuum micro-cavity interferometer chip and a manufacturing method therefor, and a low-drift optical pressure sensor. The vacuum micro-cavity interferometer chip comprises a first substrate (1), a second substrate (2) and a third substrate (3), which are connected by means of bonding. A membrane-island structure is formed on an upper surface of the first substrate (1), the membrane-island structure comprising a protrusion (11) and a pressure-sensitive membrane (12) surrounding the protrusion; and a first sidewall portion (13), a getter cavity (14), a second sidewall portion (15) and an F-P interference cavity (16) located at the center are sequentially provided on a lower surface of the first substrate (1) in a radial direction thereof. A first reflective face (112) is deposited on the lower surface of the first substrate within the F-P interference cavity, and a second reflective face (113) is deposited on an upper surface of the second substrate in the F-P interference cavity. A first optical anti-reflection coating (111) is disposed on the surface of the protrusion (11), and the first optical anti-reflection coating (111), the protrusion (11), the pressure-sensitive membrane (12), the first reflective face (112) and the second reflective face (113) are concentric. The vacuum micro-cavity interferometer chip further comprises a vent hole (142), wherein the vent hole is formed in the second sidewall portion (15) and is used for communicating the getter cavity (14) with the F-P interference cavity (16). The welding of the chip to a sensor housing (5) is achieved by means of welding the second substrate (2) and the housing (5), thereby significantly reducing the impact of the residual stress and thermal expansion and contraction of the housing and a solder on a sensitive membrane and an optical fiber collimator of the pressure sensor, so that the zero-point stability of the pressure sensor can be effectively improved.

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