Thermally Shorted Bolometer Reference Sensor Design
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing bolometer designs face challenges in fabricating a thermally shorted reference sensor using the same manufacturing processes as fast-release sensors, particularly with serpentine structures that require a fast release etch without release holes, limiting flexibility in release etch time and compatibility with improved sensor structures.
Innovation Solution
A MEMS sensor assembly with a reference sensor featuring conductive legs forming a tortuous path and thermal shorting portions extending from the absorber to the substrate, allowing for thermal shorting while maintaining electrical isolation, enabling the same manufacturing processes as fast-release sensors and providing greater flexibility in release etch time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a fast release etch process is used for serpentine structures without release holes, then manufacturing compatibility is improved, but flexibility in release etch time is reduced
Solution Approach 1:
The reference sensor absorber is segmented into multiple conductive legs that are spaced apart and define a tortuous path. This segmentation allows the etch solution to access and remove the sacrificial material from multiple locations simultaneously, enabling complete release without requiring prolonged etching or release holes, thus maintaining manufacturing compatibility while achieving adequate release flexibility.
Solution Approach 2:
The conductive legs are arranged in a tortuous path configuration that extends in multiple directions and dimensions. This dimensional arrangement increases the effective surface area exposed to the etch solution, allowing complete release of the absorber from the sacrificial material without requiring additional etch time or process modifications.
2Reliability
If thermal shorting portions are added to the reference sensor, then thermal shorting capability is improved, but device complexity increases
Solution Approach 1:
The thermal shorting portions are merged with the conductive legs of the absorber, forming an integrated structure where the same conductive material serves both as the absorber leg and as the thermal shorting path. This merging eliminates the need for separate thermal shorting components, thereby improving thermal shorting capability while avoiding additional device complexity.
Solution Approach 2:
The conductive legs serve multiple functions: they provide structural support for the absorber, conduct electrical signals, and simultaneously act as thermal shorting paths to the substrate. This multi-functionality achieves reliable thermal shorting without adding dedicated thermal management components, thus avoiding increased device complexity.
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 allows for the fabrication of thermally shorted reference sensors that share the same electrical characteristics as the main sensor, enhancing sensitivity and flexibility in the release etch process, and effectively compensating for substrate temperature influences and process variations.
Implementation Method 1
thermal shorting portions extending from the absorber to the substrate, allowing for thermal shorting
Implementation Method 2
bolometers must first absorb incident electromagnetic radiation to induce a change in temperature
Implementation Method 3
the temperature change caused by incoming photons can be measured using temperature-dependant resistors (thermistors)
Data Source
AI summary
In one embodiment, A MEMS sensor assembly includes a substrate, a first sensor supported by the substrate and including a first absorber spaced apart from the substrate, and a second sensor supported by the substrate and including (i) a second absorber spaced apart from the substrate, and (ii) at least one thermal shorting portion integrally formed with the second absorber and extending downwardly from the second absorber to the substrate thereby thermally shorting the second absorber to the substrate.