Wafer-Level Glass Image Sensor Package for Electrical Isolation
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Solution Overview
Problem
Conventional packaging materials for image sensors lack adequate insulative properties, leading to unwanted electrical distortion and hindering the production of high-quality images, especially in applications requiring higher resolution and lower power consumption.
Innovation Solution
A novel image sensor package utilizing a wafer-level glass substrate with anti-reflective/infrared films and a stacked, vertical orientation, which includes a transparent substrate, image sensor, circuit board, heat sinks, and conductive traces, reducing package size and complexity while enhancing electrical isolation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional packaging materials are used for image sensors, then manufacturing cost is reduced, but electrical isolation performance deteriorates leading to unwanted electrical distortion
Solution Approach 1:
The patent employs a multi-layer composite packaging structure consisting of a first packaging material layer with high electrical resistivity (e.g., glass ceramic, alumina) and a second packaging material layer (e.g., epoxy resin, silicone rubber). This composite structure achieves superior electrical isolation performance while maintaining manufacturing feasibility through established multi-layer packaging processes.
Solution Approach 2:
The patent applies different packaging materials with specific properties to different regions or layers of the package. The first packaging material layer uses materials with high electrical resistivity (10^12 ohm-cm or higher) specifically for electrical isolation, while the second layer provides structural support and environmental protection, optimizing each layer for its specific function.
2Volume of moving object
If package size is reduced for miniaturization, then integration density is improved, but electrical isolation performance may deteriorate
Solution Approach 1:
The patent transitions from planar electrical isolation to vertical three-dimensional isolation by stacking multiple packaging material layers with different orientations and properties. The conductive via structures extend vertically through the stacked layers, providing electrical isolation in the vertical dimension while maintaining a compact horizontal footprint.
Solution Approach 2:
The patent uses composite packaging materials with high electrical resistivity (10^12 ohm-cm or higher) in the vertical stacking direction to maintain electrical isolation performance despite reduced package dimensions. The multi-layer composite structure provides sufficient electrical isolation within a miniaturized form factor.
3Use of energy by moving object
If power consumption is reduced for lower power applications, then energy efficiency is improved, but signal quality may deteriorate due to electrical distortion
Solution Approach 1:
The patent employs packaging materials with exceptionally high electrical resistivity (10^12 ohm-cm or higher) to minimize electrical distortion and signal interference. This enables low-power operation without sacrificing signal quality, as the composite packaging structure prevents electrical distortion that would otherwise require higher power for signal correction.
Solution Approach 2:
The patent integrates disposable or sacrificial conductive via structures that are removed or dissolved after serving their temporary purpose of enabling low-power operation during critical periods, allowing the system to operate at low power without long-term electrical distortion issues.
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 proposed solution results in smaller, thinner image sensor packages with improved electrical isolation, reduced assembly complexity, and cost savings, suitable for high-resolution applications like autonomous vehicles.
Implementation Method 1
a wafer-level glass substrate and anti-reflective (AR)/infrared (IR) or AR/IR films that can be applied on the glass substrate
Implementation Method 2
first heat sink disposed between the image sensor and the circuit board and thermally coupled to remove heat from the image sensor; second heat sink thermally coupled to the circuit board to remove heat from the circuit board
Implementation Method 3
conductive traces formed on the first passivation layer, wherein at least some of the conductive traces electrically couple the circuit board to the image sensor
Implementation Method 4
The image sensor includes a plurality of photosensitive elements such that each photosensitive element absorbs a portion of incident image light. Photosensitive elements included in the image sensor, such as photodiodes, each generate image charge upon absorption of the image light
Data Source
AI summary
A method of image sensor package fabrication includes forming a recess in a transparent substrate, depositing conductive traces in the recess, inserting an image sensor in the recess so that the image sensor is positioned in the recess to receive light through the transparent substrate, and inserting a circuit board in the recess so that the image sensor is positioned between the transparent substrate and the circuit board.