Dual-Facing BSI Image Sensor Stacking for Compact Dual Capture
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Solution Overview
Problem
Current mobile electronic devices with dual-facing camera capabilities often rely on two image sensors, which can be bulky and inefficient, limiting image resolution and quantum efficiency.
Innovation Solution
Integration of two backside-illuminated (BSI) image sensors with a processor wafer using wafer level stacking methods, where the processor is bonded between the BSI image sensors, allowing for efficient light capture and image processing on both sides of the device.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If two image sensors are used for dual-facing camera capability, then image capture from both front and back is enabled, but device size and bulk increase
Solution Approach 1:
The patent merges two separate image sensors into a single integrated unit by bonding two BSI image sensor wafers to opposite sides of a processor wafer. This combination allows dual-facing image capture while reducing overall device volume compared to using two independent sensors.
Solution Approach 2:
The patent transitions from a planar arrangement of separate sensors to a three-dimensional stacked configuration. By bonding sensor wafers to opposite sides of a processor wafer, the solution utilizes the vertical dimension to achieve dual-facing capability while minimizing footprint.
2Adaptability or versatility
If traditional image sensors are used, then dual-facing camera function is achieved, but image resolution and quantum efficiency are limited
Solution Approach 1:
The patent changes the fundamental parameter of sensor illumination architecture by using backside-illuminated (BSI) sensors instead of traditional front-side illuminated sensors. This parameter change enables shorter optical paths and higher quantum efficiency, directly improving image resolution and detection precision.
Solution Approach 2:
The patent creates a composite structure by bonding BSI image sensor wafers to a processor wafer. This composite architecture integrates light detection and processing functions, enabling both high-resolution imaging and computational photography capabilities.
3Adaptability or versatility
If two separate image sensors are used, then dual-facing capture is enabled, but system complexity and inefficiency increase
Solution Approach 1:
The patent combines two separate sensor systems into a single integrated unit where sensor wafers are bonded to opposite sides of a shared processor wafer. This merging reduces system complexity by eliminating redundant components and interconnections while maintaining dual-facing capture capability.
Solution Approach 2:
The processor wafer serves multiple functions: it processes images from the front sensor, processes images from the back sensor, and provides structural support for the entire assembly. This multi-functionality reduces overall system complexity.
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 enhances image resolution, quantum efficiency, and reduces device size, enabling effective dual-facing image capture with improved performance.
Implementation Method 1
The first substrate includes a photodiode region for accumulating an image charge in response to radiation incident upon a second side of the first substrate
Data Source
AI summary
A device includes two BSI image sensor elements and a third element. The third element is bonded in between the two BSI image sensor elements using element level stacking methods. Each of the BSI image sensor elements includes a substrate and a metal stack disposed over a first side of the substrate. The substrate of the BSI image sensor element includes a photodiode region for accumulating an image charge in response to radiation incident upon a second side of the substrate. The third element also includes a substrate and a metal stack disposed over a first side of the substrate. The metal stacks of the two BSI image sensor elements and the third element are electrically coupled.