Thermoelectric Cooling for Image Sensor Detector Arrays
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Solution Overview
Problem
Elevated temperatures negatively impact the performance of image sensors due to increased leakage currents and thermal noise, and existing thermal management techniques for integrated circuits are inefficient, particularly in power-constrained devices like mobile devices, where active cooling requires significant power and additional components can increase space and power requirements.
Innovation Solution
A device with a base substrate containing an image sensor and a supporting substrate with thermoelectric structures aligned with the detector array to selectively transfer heat away from the detector array, while using a thinned base substrate and thermal isolation trenches to reduce lateral heat transfer and manage temperature without affecting peripheral circuitry.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If active cooling is used to remove heat from the entire image sensor, then the temperature of the image sensor is reduced, but the power consumption increases significantly
Solution Approach 1:
The image sensor is divided into two distinct regions: a detector array area that requires active cooling and a peripheral circuitry area that generates heat but does not require cooling. Thermoelectric structures are selectively positioned only under the detector array area, enabling region-specific thermal management that reduces overall power consumption compared to cooling the entire sensor.
Solution Approach 2:
Different thermal management approaches are applied to different regions of the image sensor. The detector array area receives active cooling through thermoelectric structures, while the peripheral circuitry area relies on passive heat dissipation. This localized quality approach optimizes power usage by applying cooling only where temperature sensitivity is critical.
2Temperature
If additional cooling components are added to image sensors, then cooling effectiveness is improved, but space requirements and device complexity increase
Solution Approach 1:
The thermoelectric structures are integrated directly into the substrate supporting the detector array, merging the cooling function with the structural support function. This integration eliminates the need for separate, discrete cooling components, thereby reducing device complexity and space requirements while maintaining effective cooling of the detector array.
Solution Approach 2:
The substrate serving the detector array is given a dual function: it provides mechanical support and simultaneously acts as a thermal management component through integrated thermoelectric structures. This multi-functionality reduces the need for additional dedicated cooling components, simplifying the overall device architecture.
3Temperature
If heat is removed from the entire image sensor, then temperature is reduced, but the power required to remove heat increases due to heat from all circuits
Solution Approach 1:
The thermal management system segments the heat removal function to address only the heat generated by the detector array area, separating it from the heat generated by peripheral circuitry. This segmentation allows the cooling system to handle a reduced thermal load, thereby reducing the power required for heat removal while still effectively cooling the temperature-sensitive detector array.
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 approach effectively reduces the thermal load on the detector array, minimizing power consumption and maintaining image quality by selectively cooling the temperature-sensitive areas without overburdening the system with heat from peripheral circuits, thus optimizing thermal management in space-constrained devices.
Implementation Method 1
The thermoelectric structures may be configured to (e.g., selectively) transfer heat away from the detector array area
Implementation Method 2
a thinned base substrate and thermal isolation trenches to reduce lateral heat transfer
Implementation Method 3
a heat isolation trench positioned between the detector array area of the base substrate and the peripheral circuitry area of the base substrate
Data Source
AI summary
Methods and devices configured to provide selective heat transfer of a temperature-sensitive circuit are provided. In an example, a device comprises a thinned base substrate including an integrated circuit (e.g., back side illuminated (BSI) image sensor comprising a detector array area and a peripheral circuitry area). The device also comprises a supporting substrate comprising one or more thermoelectric structures. The supporting substrate may be coupled to the base substrate such that the one or more thermoelectric structures are aligned with the detector array area, and the thermoelectric structures may be configured to transfer heat away from the detector array area, while a reduced cross-section of a thinned base substrate may be configured to substantially reduce lateral heat flow across the base substrate and enable selective heat transfer.