Optical Device Redistribution Layer Light Reflection
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Solution Overview
Problem
Conventional optical device configurations, such as those using a metal reflecting layer, are not applicable to small and thin semiconductor packages with redistribution layers, like fan-out wafer level packages, limiting their light emitting and receiving efficiency.
Innovation Solution
An optical device with a photoelectric conversion element, a redistribution layer, and external connection terminals, where the redistribution layer includes an insulating layer and reflecting portions that redirect light to improve light emitting and receiving efficiency, and a method for manufacturing this device by forming insulating layers, redistributions, and external connection terminals on the photoelectric conversion element.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a metal reflecting layer is formed on the electrode layer to improve light emitting and receiving efficiency, then the optical efficiency is improved, but the device cannot be applied to small and thin semiconductor packages with redistribution layers
Solution Approach 1:
The patent transitions from a conventional planar electrode structure to a three-dimensional stacked structure with multiple insulating layers and conductive patterns at different levels. The redistribution layer is positioned between the electrode layer and the light emitting layer, creating vertical stacking that enables both optical efficiency and compatibility with thin package structures.
Solution Approach 2:
The patent divides the electrode structure into multiple segments: the electrode layer, the redistribution layer with conductive patterns, and multiple insulating layers (first insulating layer, second insulating layer). This segmentation allows each layer to perform its specific function while maintaining overall optical efficiency and mechanical flexibility for thin packages.
2Length of moving object
If the device is made thinner to achieve miniaturization, then the device size is reduced, but stress on the semiconductor substrate increases causing variations in light sensitivity and resistance values
Solution Approach 1:
The patent applies different material properties to different regions: the first insulating layer has high stress resistance to protect the semiconductor substrate, while the second insulating layer provides planarization. The conductive patterns in the redistribution layer are strategically placed to provide electrical connection while minimizing stress transmission to the substrate.
Solution Approach 2:
The patent uses composite material structures combining multiple insulating layers with different properties (stress resistance, planarization) and conductive patterns. This composite structure achieves both thin profile and stress management, preventing variations in light sensitivity and resistance values while maintaining miniaturization.
3Adaptability or versatility
If a redistribution layer is added to enable fan out wafer level package structure, then the device can be made small and thin, but the manufacturing process becomes more complex
Solution Approach 1:
The patent merges the electrode function with the redistribution function by integrating the electrode layer and redistribution layer into a single stacked structure. The conductive patterns in the redistribution layer serve both electrical connection and light reflection purposes, reducing the need for separate components and simplifying the overall manufacturing process despite the added functional 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
The solution enhances light emitting and receiving efficiency, allows for thinner device configurations, and reduces stress on the semiconductor substrate, minimizing variations in light sensitivity and resistance values, thus improving measurement accuracy in applications like gas sensors.
Implementation Method 1
a reflecting portion disposed in a region in which, when viewed in plan, the semiconductor layer and the electrodes do not overlap each other and configured to reflect the light to a side on which the semiconductor layer is located
Data Source
AI summary
Provided are an optical device that is a small and thin optical device including a redistribution layer and has high light emitting efficiency and light receiving efficiency, and a method for manufacturing the optical device. An optical device includes: a photoelectric conversion element configured to include a semiconductor substrate, a semiconductor layer capable of receiving or emitting light, and electrodes; a sealing portion configured to expose a surface of the photoelectric conversion element on the opposite side to an electrode-formed surface of the photoelectric conversion element on which the electrodes are formed; a redistribution layer configured to include a reflecting portion disposed in a region in which, when viewed in plan, the semiconductor layer and the electrodes do not overlap each other and configured to reflect the light to a side on which the semiconductor layer is located; and external connection terminals configured to be coupled to the redistributions.