Image Sensor Stack With Inorganic Dielectric Moisture Barrier
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Image acquisition devices with inorganic photodetectors and organic color filters and microlenses fail to meet temperature and moisture resistance criteria due to performance degradation during testing.
Innovation Solution
Incorporating a layer made from inorganic dielectric materials such as silicon nitride, metal nitrides, silicon oxide, or silicon oxynitride between the color filters and microlenses, with a thickness between 30 nm and 200 nm, deposited using plasma-enhanced chemical vapor deposition at temperatures below 250°C, to enhance durability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If organic color filters and microlenses are used with inorganic photodetectors, then color selectivity and light focusing are improved, but temperature and moisture resistance deteriorate
Solution Approach 1:
An inorganic dielectric layer is introduced as an intermediary between the organic color filters and microlenses. This intermediate layer acts as a protective barrier that prevents direct interaction between moisture/temperature and the organic materials, thereby maintaining device reliability under harsh environmental conditions while preserving the optical functionality of the organic components.
Solution Approach 2:
The device structure combines organic materials (color filters and microlenses) with inorganic materials (photodetectors and the intermediate dielectric layer) to create a composite structure. This composite approach leverages the optical advantages of organic materials while using inorganic materials to provide environmental stability and resistance to temperature and moisture.
2Ease of manufacture
If organic materials are used for color filters and microlenses, then manufacturing flexibility is improved, but mechanical strength and crack resistance deteriorate
Solution Approach 1:
The inorganic dielectric layer is deposited as a thin film (50-200 nm) over the organic color filters and microlenses. This thin inorganic film provides mechanical reinforcement and crack resistance to the underlying organic structures without significantly affecting their optical properties or manufacturing flexibility, as it can be deposited using standard PECVD processes.
3Manufacturing precision
If deposition temperature is kept below 250°C, then damage to organic materials is prevented, but deposition quality may deteriorate
Solution Approach 1:
The deposition process parameters are optimized to achieve high-quality inorganic dielectric layer formation at low temperatures (below 250°C). This involves adjusting plasma power, pressure, gas flow rates, and deposition time in the PECVD process to compensate for the lower temperature, ensuring adequate film density, adhesion, and optical properties without damaging the underlying organic materials.
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 significantly improves the temperature and humidity resistance of image acquisition devices, preventing localized sensitivity losses and mechanical stress-induced cracking, thereby maintaining performance under harsh conditions.
Implementation Method 1
at least one layer made from an inorganic dielectric material between an array of color filters and an array of microlenses
Implementation Method 2
a step for depositing said layer by plasma-enhanced chemical vapor deposition. said deposition of said layer is done on the surface of the color filter array. the step for deposition of said layer is done at a temperature below 250° C.
Data Source
AI summary
An image acquisition device includes an array of color filters and an array of microlenses over the array of color filters. At least one layer made from an inorganic dielectric material is formed between the array of color filters and the array of microlenses.