Bolometer Silicon Via Interconnect Design
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Solution Overview
Problem
Current non-refrigerating bolometers, such as vanadium oxide microbridge bolometers, require strict chemical-mechanical polishing and reserved space for signal export, limiting their downsizing potential due to integrated process requirements and surface flattening needs.
Innovation Solution
The bolometer design separates the thermal radiation measurement element and readout circuit onto different substrates, with a silicon via filled with conductive material connecting them, eliminating the need for strict surface flattening and reserved space for signal export, allowing for a reduced device size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the thermal radiation measurement element and readout circuit are integrated on the same substrate, then electrical connection can be achieved, but strict chemical-mechanical polishing is required and space must be reserved for signal export, limiting device downsizing
Solution Approach 1:
The patent divides the bolometer into two separate substrates: the first substrate contains the thermal radiation measurement element, while the second substrate contains the readout circuit. This segmentation eliminates the need for strict surface flattening and reserved signal export space on a single substrate, enabling device downsizing while maintaining electrical connection through silicon via technology.
2Manufacturing precision
If strict chemical-mechanical polishing is performed to flatten the silicon wafer surface, then uniformity of surface height is controlled, but the process complexity and time increase
Solution Approach 1:
The patent extracts the readout circuit from the same substrate as the thermal radiation measurement element and places it on a separate second substrate. This extraction eliminates the need for strict chemical-mechanical polishing to achieve surface height uniformity, significantly reducing process time and complexity while maintaining electrical connection through the silicon via structure.
3Ease of operation
If reserved space is allocated for signal export on the edge of the microbridge, then electrical signals can be exported, but the detection unit size increases
Solution Approach 1:
The patent segments the electrical connection path by using silicon via technology to connect the thermal radiation measurement element on the first substrate to the readout circuit on the second substrate. This segmentation eliminates the need for reserved signal export space on the microbridge edge, enabling compact detection unit design while maintaining full signal export capability.
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
This design reduces the size of the bolometer and lowers process integration and control requirements, enabling more compact and efficient thermal radiation detection without the need for complex surface flattening processes.
Implementation Method 1
the electrode hole of the thermal radiation measurement element is electrically connected to the electrode of the readout circuit via the conductive material filled in the silicon via
Implementation Method 2
It realizes thermal detection by a vanadium oxide thermosensitive film with a high temperature coefficient of resistance (TCR) on the surface of the microbridge
Data Source
AI summary
A bolometer and a preparation method thereof. The bolometer includes: an infrared detection element (1) and a readout circuit (2), wherein the infrared detection element (1) is formed on one side of a first substrate (100), and an edge of the infrared detection element (1) is provided with an electrode hole (9), and the readout circuit (2) is formed on one side of a second substrate (200) and the readout circuit (2) has an electrode, the first substrate (100) is formed thereon with a silicon via (8) passing through the first substrate (100) and filed with a conductive material, the electrode hole (9) of the infrared detection element (1) is electrically connected to the electrode of the readout circuit (2) via the conductive material filled in the silicon via (8). The following defects are overcome: bolometers in the prior art need to flatten the silicon wafer surface with a suitable chemical-mechanical polishing process after a readout circuit thereof has been manufactured, the circuit is large in area, and the requirements of the system integration process are high.