Microbolometer Vertical Leg Structure for Higher Array Fill Factor
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Solution Overview
Problem
The challenge in designing efficient microbolometer systems is to reduce the area occupied by leg supports while maintaining device performance, as they limit the fill factor of the array and scaling the width and length of legs with the pixel area is difficult.
Innovation Solution
The implementation of vertically oriented microbolometer legs, formed using spacer deposition and etch processing, which run along the sidewalls of an opening in a sacrificial layer and are suspended above the substrate, reducing the surface area occupied without compromising leg performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of moving object
If conventional horizontal leg supports are used to connect microbolometer pixels to contacts, then the structural integrity and electrical connection are maintained, but the area occupied by leg supports increases significantly, reducing the fill factor of the array
Solution Approach 1:
The patent transitions from conventional horizontal leg supports extending in the plane of the array to vertical leg supports that extend perpendicular to the array plane. This dimensional change allows the legs to connect the microbolometer pixel to the contact below without occupying significant area in the array plane, thereby increasing the fill factor while maintaining structural and electrical connectivity.
2Area of moving object
If the width and length of leg supports are reduced to increase fill factor, then the area occupied by legs decreases, but the structural integrity and device performance may be compromised
Solution Approach 1:
By extending the leg supports vertically rather than horizontally, the patent achieves the necessary structural strength and electrical connection without requiring large dimensions in the array plane. The vertical orientation provides sufficient mechanical support and conductive path while minimizing the footprint area, thus resolving the conflict between fill factor and structural integrity.
3Area of moving object
If vertical leg structures are implemented to reduce area occupation, then the fill factor increases, but the manufacturing process complexity increases due to spacer deposition and etch processing
Solution Approach 1:
The manufacturing process is divided into distinct sequential steps: forming sacrificial layers, depositing spacers on sidewalls, patterning, etching, and removing sacrificial materials. This segmentation of the complex vertical leg formation process into manageable stages makes the manufacturing feasible despite the increased complexity compared to conventional horizontal legs.
Data Source
AI summary
Microbolometer systems and methods are provided herein. For example, an infrared imaging device includes a substrate having contacts and a surface. The surface defines a plane. The infrared imaging device further includes a microbolometer array coupled to the substrate. Each microbolometer of the microbolometer array includes a cross-section having a first section, a second section substantially parallel to the first section, and a third section joining the first section and the second section.