Integrated Pressure Sensor Chip with Dual Diaphragms
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Solution Overview
Problem
Existing pressure sensors are limited in size reduction due to the separate integration of differential-pressure and static-pressure sensor chips, which complicates the manufacturing process and requires diaphragms of different thicknesses in the same semiconductor substrate.
Innovation Solution
A pressure sensor chip is designed with two integrated diaphragms in the same chip, where the first diaphragm measures pressure relative to a sealed cavity and the second diaphragm measures differential pressure, allowing for different thicknesses without complicating the manufacturing process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the differential pressure sensor and the static pressure sensor are integrated in the same chip, then the size of the pressure sensor is reduced, but the manufacturing process becomes complicated due to different diaphragm thicknesses
Solution Approach 1:
The chip is divided into multiple layers (first layer, second layer, third layer, fourth layer) with each layer serving specific functions. The first and third layers have different thicknesses to accommodate the different diaphragm thickness requirements, while maintaining a unified chip structure that reduces overall size.
Solution Approach 2:
Different regions of the chip have different thicknesses to meet specific functional requirements. The first diaphragm region has a greater thickness to withstand large pressure for static pressure measurement, while the second diaphragm region has a smaller thickness for differential pressure measurement, allowing both functions to coexist in the same chip.
2Ease of manufacture
If the differential pressure sensor chip and the static pressure sensor chip are provided as separate chips, then the manufacturing process is simplified, but the size of the pressure sensor increases
Solution Approach 1:
The differential pressure sensor and static pressure sensor are merged into a single chip structure with multiple layers. This integration reduces the overall number of components and assembly steps while maintaining the simplicity of the manufacturing process through standardized layer fabrication techniques.
Solution Approach 2:
The multi-layer chip structure serves multiple functions simultaneously: the first diaphragm measures static pressure while the second diaphragm measures differential pressure. This universal design allows a single chip to perform both measurement functions, eliminating the need for separate chips.
3Measurement precision
If the diaphragm for the static pressure sensor has a greater thickness to withstand large pressure, then the pressure measurement accuracy is improved, but the chip size and complexity increase
Solution Approach 1:
The solution transitions from a single-layer planar structure to a multi-layer vertical structure. By stacking layers with different thicknesses, the chip achieves both the required diaphragm thickness for accurate static pressure measurement and a compact overall form factor, effectively utilizing the vertical dimension to resolve the contradiction.
Data Source
AI summary
A pressure sensor chip includes a base, a first layer including a first cavity and joined to an upper surface of the base, a second layer joined to an upper surface of the first layer, a third layer including a second cavity and joined to an upper surface of the second layer, and a fourth layer including a third cavity and joined to an upper surface of the third layer. The second layer includes a first diaphragm between the first and second cavities. The fourth layer includes a second diaphragm between the second cavity and a space in communication with outside. A top end of the third cavity is in communication with outside. The bottom end of the third cavity is in communication with the second cavity. The first cavity is sealed. The pressure in the first cavity is lower than the pressure in the second cavity.