3D Stacked Light Sensing Device for Enhanced Infrared Absorption
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Solution Overview
Problem
Conventional infrared sensing units face challenges in achieving favorable light absorption and conversion efficiency due to their small effective light sensing region and complex manufacturing processes, which hinder economic scalability and yield improvement.
Innovation Solution
A light sensing device is designed with a substrate having a recessed portion, a semiconductor device layer, and a metal and insulation material stacked structure that includes interconnect structures and a light absorption layer, allowing for heat exchange between different levels and simplifying the manufacturing process by forming gaps through etching to enhance light absorption and conversion efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the conventional infrared sensing unit is integrated with reading circuit on IC wafer using standard manufacturing process, then the manufacturing complexity is reduced and yield is improved, but the effective light sensing region becomes small and light absorption efficiency is reduced
Solution Approach 1:
The patent transitions from a planar integration approach to a three-dimensional stacked architecture. The light absorption layer is positioned at a different vertical level (z-dimension) above the semiconductor device layer, allowing the light sensing region to extend vertically rather than being constrained to a two-dimensional plane. This dimensional change enables both standard IC manufacturing processes and large effective light sensing area to coexist.
Solution Approach 2:
The patent divides the device into distinct functional layers: a light absorption layer for photon detection and a semiconductor device layer for signal processing. This segmentation allows each layer to be optimized independently - the light absorption layer can be designed with large area for maximum light capture, while the semiconductor layer maintains standard IC fabrication compatibility, thus resolving the contradiction between manufacturing ease and sensing area.
2Loss of energy
If the light absorption layer and semiconductor device layer are positioned at different levels and connected through interconnect structure, then the heat exchange efficiency is improved and light absorption area is increased, but the device structure becomes more complex
Solution Approach 1:
The first interconnect structure serves multiple functions simultaneously: it provides electrical connection between the light absorption layer and semiconductor device layer, acts as a thermal conduction pathway for heat exchange, and serves as a structural support element. This multi-functionality reduces the need for separate dedicated thermal management structures, thereby limiting the increase in device complexity while achieving improved heat exchange efficiency.
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 increases the light absorption area and improves the infrared sensing efficiency by allowing the light absorption layer and semiconductor device layer to exchange heat effectively, while simplifying the manufacturing process and enhancing temperature sensing sensitivity.
Implementation Method 1
the light absorption layer and the semiconductor device layer located at different levels can be connected to each other and exchange heat
Data Source
AI summary
A light sensing device includes a substrate, a semiconductor device layer, a metal and insulation material stacked structure, and a light absorption layer. The substrate has a recessed portion. The semiconductor device layer is located on the substrate. The metal and insulation material stacked structure is located on the semiconductor device layer and includes a first interconnect structure, a second interconnect structure surrounding the first interconnect structure, and a device conductive line. The light absorption layer is located on the metal and insulation material stacked structure. The first interconnect structure is located between the light absorption layer and the semiconductor device layer, such that the light absorption layer and the semiconductor device layer located at different levels can be connected to each other and exchange heat.