Capacitive Sensor With Upstanding Conductive Pillars
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Solution Overview
Problem
Capacitive sensors have limitations in sensitivity for detecting substances like humidity, gases, or fluids, as existing designs do not allow for precise tailoring of sensitivity to application requirements.
Innovation Solution
A capacitive sensor design featuring upstanding conductive pillars in a first layer, with electrodes connected to these pillars and a dielectric material that alters capacitance in response to the presence of substances, allowing for tailored sensitivity through precise distribution and spacing of pillars.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional capacitive sensor designs with planar electrodes are used, then the sensor structure is simple and easy to manufacture, but the sensitivity is insufficient and cannot be precisely tailored to application requirements
Solution Approach 1:
The patent transitions from conventional planar (2D) electrode designs to three-dimensional upstanding conductive pillars. This dimensional change increases the effective surface area and capacitance of the sensor, thereby enhancing sensitivity. The pillars extend vertically from the substrate, creating additional capacitance pathways that are not available in planar designs, while still maintaining compatibility with standard semiconductor manufacturing processes.
Solution Approach 2:
The patent employs different pillar heights within the same sensor structure to create local variations in capacitance. By having pillars of different heights, the sensor can be optimized for specific detection ranges or substances. This local quality variation allows precise tailoring of sensitivity to match specific application requirements without redesigning the entire sensor structure.
2Measurement precision
If humidity sensitive material is used to increase sensitivity, then the sensor can detect smaller levels of humidity, but the dielectric material may be affected by substances other than water vapour
Solution Approach 1:
The patent changes the fundamental parameter of capacitance enhancement from relying on material properties (humidity-sensitive dielectric materials) to relying on geometric configuration (pillar dimensions, spacing, and arrangement). By controlling the physical parameters of the pillar structure, sensitivity is enhanced without introducing material selectivity issues. The same pillar structure can work with different dielectric materials optimized for specific substances.
3Measurement precision
If new sensor designs are developed to improve sensitivity, then detection performance is enhanced, but manufacturing complexity increases and integration with existing IC processes becomes difficult
Solution Approach 1:
The patent designs the upstanding pillar structure to be compatible with existing semiconductor manufacturing processes that are already used for standard IC fabrication. The pillar formation can be integrated into conventional via and contact hole processes, allowing the same manufacturing infrastructure to produce both standard ICs and enhanced sensitivity sensors. This universality enables mass production without requiring entirely new manufacturing lines.
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 sensor achieves enhanced sensitivity by optimizing the distribution and spacing of conductive pillars, enabling detection of substances such as humidity, CO2, O2, ethylene, and NH3, and can be integrated into existing IC manufacturing processes without additional steps.
Implementation Method 1
a capacitive sensor for detecting the presence of a substance... a dielectric material for altering the capacitance of the first and second groups of pillars in response to the presence of said substance
Implementation Method 2
a dielectric material for altering the capacitance of the first and second groups of pillars in response to the presence of said substance
Data Source
AI summary
A capacitive sensor for detecting the presence of a substance includes a plurality of upstanding conductive pillars arranged within a first layer of the sensor, a first electrode connected to a first group of the pillars, a second electrode connected to a second, different group of the pillars, and a dielectric material arranged adjacent the pillars, for altering the capacitance of the sensor in response to the presence of said substance.