Hybrid MEMS ASIC Capacitive Sensor Differential Electrode Design
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Solution Overview
Problem
Existing MEMS components with capacitive detection or excitation principles face challenges in achieving high sensitivity and offset stability, particularly in micromechanical sensors, due to limitations in electrode design and assembly processes.
Innovation Solution
A hybrid integrated component is developed with a differential capacitor system, where the MEMS element has buried 'out-of-plane' electrodes and the ASIC element features additional counter electrodes, allowing for high sensitivity and vibration resistance, along with flexible wiring for reduced parasitic capacitances and mechanical overload protection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a single-sided capacitor system is used in MEMS components, then the structure is simple, but sensitivity and offset stability are insufficient
Solution Approach 1:
The capacitor system is segmented into two independent capacitor systems: a first capacitor system with a first movable electrode and first stationary electrode, and a second capacitor system with a second movable electrode and second stationary electrode. This segmentation enables differential measurement, improving sensitivity and offset stability while maintaining manageable structural complexity through modular design.
Solution Approach 2:
The patent employs asymmetric electrode configurations where movable electrodes are positioned at different locations on the MEMS structure, and stationary electrodes are arranged asymmetrically on the substrate. This asymmetric arrangement optimizes the capacitive coupling for differential measurement, enhancing measurement precision while balancing the overall structural complexity.
2Measurement precision
If electrode area is increased to improve sensitivity, then sensitivity improves, but chip area increases
Solution Approach 1:
The capacitor electrodes are strategically positioned in specific local regions of the MEMS structure where capacitive coupling is most effective. By concentrating electrode areas in optimal locations rather than distributing them uniformly, the design achieves high sensitivity with minimal chip area occupation.
Solution Approach 2:
The patent utilizes the third dimension (vertical spacing) to optimize capacitor performance. By controlling the spacing between movable and stationary electrodes in the vertical dimension, high sensitivity is achieved without proportionally increasing the horizontal chip area, effectively trading vertical for horizontal space.
3Ease of manufacture
If conventional wiring is used in MEMS components, then manufacturing is simple, but parasitic capacitances are high
Solution Approach 1:
Wiring routes are extracted and routed through the substrate rather than along the surface. This extraction of wiring from the conventional surface layout into the substrate interior removes the wiring from proximity to sensitive capacitive elements, eliminating parasitic capacitance coupling while maintaining manufacturing feasibility through standard substrate through-hole or via techniques.
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 achieves high sensitivity and offset stability in micromechanical sensors, enhancing vibration resistance and reducing parasitic capacitances, while maintaining a compact chip area and hermetic sealing for environmental protection.
Implementation Method 1
The present invention refines a hybrid integrated component including an MEMS element and an ASIC element, whose micromechanical function is based on a capacitive detection or excitation principle
Implementation Method 2
The present invention refines a hybrid integrated component including an MEMS element and an ASIC element, whose micromechanical function is based on a capacitive detection or excitation principle
Data Source
AI summary
A hybrid integrated component including an MEMS element and an ASIC element is refined to improve the capacitive signal detection or activation. The MEMS element is implemented in a layered structure on a semiconductor substrate. The layered structure of the MEMS element includes at least one printed conductor level and at least one functional layer, in which the micromechanical structure of the MEMS element having at least one deflectable structural element is implemented. The ASIC element is mounted face down on the layered structure and functions as a cap for the micromechanical structure. The deflectable structural element of the MEMS element is equipped with at least one electrode of a capacitor system. At least one stationary counter electrode of the capacitor system is implemented in the printed conductor level of the MEMS element, and the ASIC element includes at least one further counter electrode of the capacitor system.