Etch Stop Layer for Buffer Layer Uniformity in Image Sensors
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Solution Overview
Problem
Existing image sensor device structures face issues with surface roughness and uniformity of the buffer layer due to the lack of an etch stop layer, leading to performance degradation and non-uniform thickness, which affects the overall image sensing capability.
Innovation Solution
Incorporating an etch stop layer, such as aluminum oxide or zirconium oxide, between the buffer layer and the metal grid structures to protect underlying layers from etching, ensuring surface smoothness and uniform thickness, and using metal grid structures with reflective properties to guide light effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If no etch stop layer is used, then the device structure is simpler, but the buffer layer exhibits surface roughness and non-uniform thickness
Solution Approach 1:
An etch stop layer comprising aluminum oxide and zirconium oxide is introduced between the buffer layer and the metal grid structure. This intermediary layer prevents etching of the buffer layer by the metal etchant, thereby maintaining buffer layer uniformity and surface smoothness while enabling the formation of the metal grid structure.
2Manufacturing precision
If the buffer layer is directly exposed to metal etching processes, then the manufacturing process is shorter, but the buffer layer thickness becomes non-uniform
Solution Approach 1:
The etch stop layer is formed on the buffer layer before the metal grid structure is deposited. This preliminary protective action ensures that when subsequent metal etching processes are performed, the buffer layer thickness remains uniform and controlled, as the etch stop layer prevents any etching of the buffer layer.
3Reliability
If the buffer layer surface is rough, then additional protective layers are needed, but the overall device performance degrades
Solution Approach 1:
The etch stop layer serves as a protective intermediary that prevents etching-induced surface roughness on the buffer layer. By blocking the etchant from contacting the buffer layer, the etch stop layer maintains a smooth buffer layer surface, thereby preserving device performance without requiring additional corrective layers.
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 etch stop layer improves surface roughness and uniformity of the buffer layer, enhancing the performance of the image sensor device by maintaining controlled thickness and improving light guidance, resulting in better image sensing capabilities.
Implementation Method 1
an etch stop layer, such as aluminum oxide or zirconium oxide, between the buffer layer and the metal grid structures to protect underlying layers from etching
Implementation Method 2
using metal grid structures with reflective properties to guide light effectively
Data Source
AI summary
An image sensor structure is provided. The image sensor device structure includes a substrate, and the substrate includes an array region and a peripheral region. The image sensor device structure includes an anti-reflection layer formed on the substrate and a buffer layer formed on the anti-reflection layer. The image sensor device structure includes a first etch stop layer formed on the buffer layer and a metal grid structure formed on the first etch stop layer. The image sensor device structure also includes a dielectric layer formed on the metal grid structure.