Infrared Sensor Thermal Management via Substrate Heat Diffusion
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Solution Overview
Problem
Infrared sensors with bolometer membranes face challenges in minimizing the influence of heat from local heat sources, such as the ROIC, which can affect temperature measurements by transmitting heat to the bolometer membranes through soldering members and leads.
Innovation Solution
The design incorporates a first and second substrate with an inner space, where the bolometer membranes are supported by the second substrate and connected via leads that physically contact the second substrate, allowing heat from the local heat source to diffuse into the substrate, thereby reducing its impact on the bolometer membranes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the ROIC and bolometer membranes are arranged on different wafers to limit heat influence, then the local heat source effect is reduced, but heat is still transmitted through soldering members and leads to the bolometer membranes
Solution Approach 1:
The patent introduces a lead as an intermediary component that physically contacts the second substrate (wafer 2) along its entire length. This lead acts as a heat sink, absorbing and dissipating heat away from the bolometer membrane. The lead's physical contact with the wafer creates a thermal pathway that redirects heat away from the sensitive measurement area, effectively using the wafer itself as a heat management component.
Solution Approach 2:
The patent transitions from a three-dimensional vertical stacking arrangement (where heat travels directly through soldering members from one wafer to another) to a two-dimensional planar configuration where the lead extends along the wafer surface. This dimensional change increases the heat dissipation path length and allows heat to be distributed across a larger area of the wafer, reducing localized thermal effects on the bolometer membrane.
2Reliability
If soldering members and leads are used to connect ROIC to bolometer membranes, then electrical connection is achieved, but heat is transmitted from the local heat source to the bolometer membranes
Solution Approach 1:
The lead serves a dual function as both an electrical connector and a thermal intermediary. By making the lead physically contact the second substrate along its entire length, the patent creates a thermal management pathway that separates the electrical connection function from the thermal transmission problem. The wafer acts as an intermediary heat sink that absorbs excess thermal energy while allowing electrical signals to pass through the lead to the bolometer membrane.
Solution Approach 2:
The patent changes the thermal parameter of the connection system by modifying how the lead interacts with the substrate. Instead of a point contact or suspended configuration, the lead is configured to have extended physical contact with the wafer, fundamentally changing the thermal conductivity and heat dissipation characteristics of the electrical connection path. This parameter change transforms the lead from a simple electrical conductor into an integrated thermal management component.
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 configuration effectively limits the thermal influence on bolometer membranes, improving measurement accuracy by lengthening the heat transfer path and absorbing heat into the substrate, thus minimizing local heating effects.
Implementation Method 1
Heat that is transmitted from the local heat source to the lead via the first electric connection member diffuses into the second substrate through the physical contact portion along the path
Implementation Method 2
since the second substrate functions as a heat absorber that absorbs the heat of the lead, the influence on a bolometer membrane that is caused by heat from a local heat source can be limited
Implementation Method 3
a temperature change occurs in bolometer membranes due to infrared rays that enter the bolometer membranes from outside and that is absorbed by the bolometer membranes
Data Source
AI summary
An electromagnetic wave sensor that limits the influence on bolometer membranes that is caused by heat from a local heat source is provided. Electromagnetic wave sensor has first substrate, second substrate that faces first substrate so as to form inner space between first substrate and second substrate, wherein second substrate transmits infrared rays; a plurality of bolometer membranes that is provided in inner space and that is supported by second substrate; local heat source that is formed in first substrate; first electric connection member that connects first substrate to second substrate; and lead that extends on or in second substrate and that connects first electric connection member to bolometer membrane.