Monolithically Integrated MEMS Pressure Sensor on CMOS Substrate
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Solution Overview
Problem
Conventional MEMS pressure sensors have limitations in size, performance, and cost due to standalone micromachining techniques, which restrict their application in consumer, industrial, and medical fields.
Innovation Solution
A monolithically integrated MEMS pressure sensor is developed on top of a CMOS substrate using IC-foundry compatible processes, featuring a diaphragm with a corrugated structure and stress relief, encapsulated by a thick insulating layer, enabling high performance, small form factor, and low cost.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional micromachining techniques (MEMS) are used to fabricate pressure sensors, then discrete MEMS based devices can be produced, but the devices have limitations in size, performance, and cost
Solution Approach 1:
The patent merges the MEMS pressure sensor fabrication with standard CMOS integrated circuit manufacturing processes. The pressure sensor is monolithically integrated on the CMOS substrate, combining the micromachined sensing element with signal processing circuits in a single device, eliminating the need for separate MEMS fabrication steps and improving performance while reducing complexity.
Solution Approach 2:
The invention uses standard CMOS fabrication processes that are already widely used for integrated circuits, making the pressure sensor manufacturing universal and compatible with existing semiconductor manufacturing infrastructure. This multi-functional approach allows the same fabrication line to produce both digital logic circuits and pressure sensors.
2Ease of manufacture
If standalone MEMS micromachining techniques are used, then discrete pressure sensors can be fabricated, but size and cost limitations arise
Solution Approach 1:
The pressure sensor is monolithically integrated with CMOS circuits on a single substrate, dramatically reducing the overall device volume. The micromachined diaphragm structure is fabricated directly on the CMOS chip, eliminating the need for separate MEMS packaging and reducing the form factor to the smallest possible size.
3Reliability
If conventional MEMS techniques are used, then pressure sensors can be produced, but cost and performance limitations persist
Solution Approach 1:
The invention leverages standard CMOS fabrication processes that are already optimized for high-volume production, significantly reducing manufacturing costs. By using existing semiconductor manufacturing infrastructure rather than specialized MEMS facilities, the cost of producing high-performance pressure sensors is dramatically reduced.
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
The solution provides a high-performance, compact, and cost-effective pressure sensing device suitable for various applications, including microphone integration with signal processing and logic circuits.
Implementation Method 1
a diaphragm with a corrugated structure and stress relief
Implementation Method 2
at least one or more spring devices spatially disposed within a vicinity of the one or more surface regions of the diaphragm device
Data Source
AI summary
A monolithically integrated MEMS pressure sensor and CMOS substrate using IC-Foundry compatible processes. The CMOS substrate is completed first using standard IC processes. A diaphragm is then added on top of the CMOS. In one embodiment, the diaphragm is made of deposited thin films with stress relief corrugated structure. In another embodiment, the diaphragm is made of a single crystal silicon material that is layer transferred to the CMOS substrate. In an embodiment, the integrated pressure sensor is encapsulated by a thick insulating layer at the wafer level. The monolithically integrated pressure sensor that adopts IC foundry-compatible processes yields the highest performance, smallest form factor, and lowest cost.