MEMS Pressure Sensor Integrated Signal Processing via Conductive Bonding
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Solution Overview
Problem
Traditional MEMS pressure sensor manufacturing and packaging methods result in discrete chips that are complex and costly, making them incompatible with mature IC manufacturing technologies, leading to larger sizes and higher costs.
Innovation Solution
A MEMS pressure sensor design involving two substrates, where one substrate forms the piezoresistive pressure sensing unit and the other forms the signal processing circuit, integrated through conductive bonding layers, allowing for separate manufacturing and simplified packaging compatible with IC processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional packaging process with separate chips is used, then signal processing function is achieved, but device complexity and manufacturing cost increase
Solution Approach 1:
The patent merges the pressure sensing function and signal processing function into a single integrated chip structure. The signal processing circuit is directly formed on the same substrate as the piezoresistive sensing elements, eliminating the need for separate chips and complex wire-bonding packaging processes. This integration maintains full signal processing capability while dramatically simplifying the device structure and manufacturing.
Solution Approach 2:
The single chip structure performs multiple functions: it contains both the piezoresistive pressure sensing elements and the complete signal processing circuitry needed to convert resistance changes into usable output signals. This multi-functional integration eliminates the need for separate dedicated chips for sensing and processing, reducing overall device complexity.
2Reliability
If traditional packaging process with separate chips is used, then signal processing function is achieved, but manufacturing cost increases
Solution Approach 1:
The patent combines pressure sensing and signal processing onto a single chip, enabling both functions to be manufactured using the same semiconductor fabrication processes. This eliminates the need for separate chip manufacturing, wire-bonding operations, and multi-chip assembly, thereby significantly reducing manufacturing costs while maintaining full signal processing functionality.
Solution Approach 2:
Within the single chip, the patent segments the structure into distinct functional regions: piezoresistive sensing elements in the silicon substrate and signal processing circuits formed in overlaying layers. This segmentation allows standard IC fabrication techniques to efficiently produce both sensing and processing functions in one manufacturing run.
3Manufacturing precision
If traditional deep silicon etching process is used, then sensitive diaphragm is formed, but manufacturing complexity increases
Solution Approach 1:
The patent segments the chip structure into a silicon substrate containing the sensitive diaphragm and overlaying layers containing the signal processing circuits. This segmentation allows the sensitive diaphragm to be formed using standard silicon processing techniques without requiring complex deep etching, as the diaphragm formation is integrated into the substrate preparation stage rather than requiring subsequent complex etching steps.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach reduces the size and cost of the sensor by avoiding complex packaging processes and enabling compatibility with IC manufacturing, while maintaining high precision and sensitivity.
Implementation Method 1
The piezoresistive pressure sensor applies the principle of a resistance of a silicon resistor changing under a stress (a pressure)
Implementation Method 2
the second substrate is arranged opposite to the first substrate, and the second substrate is fixedly coupled to the first substrate via the first bonding layer and the second bonding layer
Data Source
AI summary
A Micro Electromechanical System (MEMS) pressure sensor may include a first substrate provided with a sensitive diaphragm of a piezoresistive pressure sensing unit, an electrical connecting diffusion layer and a first bonding layer on a surface of the first substrate; and a second substrate provided with an inter-conductor dielectric layer, a conductor connecting layer in the inter-conductor dielectric layer and/or a second bonding layer on a surface of the second substrate. The second substrate may be arranged opposite to the first substrate, and the second substrate may be fixedly coupled to the first substrate via the first bonding layer and the second bonding layer; the pattern of the first bonding layer is corresponding to the pattern of the second bonding layer, and both the first bonding layer and the second bonding layer may be formed of a conductive material.