Pixel Array Buffer Layer Structure for Metal Diffusion Isolation
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Solution Overview
Problem
In semiconductor devices like CMOS image sensors, the diffusion of metal from metal structures into optical paths between grid structures can cause interference, and existing technologies lack effective solutions for improving adhesion between metal structures and surrounding non-metal materials, leading to reduced performance.
Innovation Solution
The implementation of a first and second barrier layer, where the first barrier layer is formed adjacent to and over metal structures, and the second barrier layer is formed underlying and conformally over the grid structures, providing isolation and improved adhesion with a passivation layer to mitigate metal diffusion and interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If metal structures are formed in optical paths to guide radiation, then radiation guidance is improved, but metal diffusion into optical paths causes interference
Solution Approach 1:
A buffer layer comprising aluminum oxide is formed between the metal structure and the optical path. This intermediary layer prevents direct contact between metal atoms and the optical path materials, thereby blocking metal diffusion while maintaining the radiation guidance function of the metal structure.
Solution Approach 2:
The optical path region is segmented into distinct zones: a first optical path region above the metal structure and a second optical path region below the metal structure, separated by the buffer layer. This segmentation isolates the metal structure from both optical path regions, preventing harmful diffusion while preserving optical functionality.
2Object-generated harmful factors
If barrier layers are added to prevent metal diffusion, then metal diffusion is reduced, but device complexity increases
Solution Approach 1:
The buffer layer is applied selectively only in regions where metal diffusion is a concern—specifically adjacent to and between metal structures and optical path regions. This localized application provides targeted protection against metal diffusion without unnecessarily increasing complexity in other device regions.
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 the adhesion between metal and non-metal materials, reduces metal diffusion into optical paths, and improves the overall performance of semiconductor devices by minimizing interference, thereby enhancing the accuracy and efficiency of radiation detection.
Implementation Method 1
a buffer layer comprising aluminum oxide... preventing diffusion of metal from the metal structure into the first dielectric layer
Data Source
AI summary
A semiconductor device includes a pixel array comprising a first pixel and a second pixel. The semiconductor device includes a metal structure overlying a portion of a substrate between the first pixel and the second pixel. The semiconductor device includes a first barrier layer adjacent a sidewall of the metal structure. The semiconductor device includes a passivation layer adjacent a sidewall of the first barrier layer. The first barrier layer is between the passivation layer and the metal structure.