Deep Device Isolation Pattern for CMOS Image Sensors
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Solution Overview
Problem
Current image sensor manufacturing processes face inefficiencies in creating deep device isolation patterns, which can lead to increased complexity and reduced integration density, affecting the overall performance of CMOS image sensors.
Innovation Solution
The proposed solution involves a method of manufacturing a CMOS image sensor with a deep device isolation pattern that includes a semiconductor pattern and an oxidized semiconductor pattern, along with side insulating and filling patterns, to improve isolation between pixel regions and enhance manufacturing efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional manufacturing processes are used to create deep device isolation patterns, then the manufacturing process becomes complex and integration density is reduced, but the isolation between pixel regions is insufficient
Solution Approach 1:
The device isolation structure is segmented into multiple functional layers: a first device isolation layer for shallow isolation, a second device isolation layer for deep isolation, and a trench isolation layer for lateral isolation. This segmentation allows each layer to perform its specific isolation function efficiently, achieving complete pixel region isolation while maintaining a relatively simple manufacturing process through standardized layer formation techniques.
2Reliability
If conventional device isolation structures are used, then manufacturing efficiency is reduced, but the isolation depth is insufficient to prevent cross-talk
Solution Approach 1:
The isolation structure extends into the vertical dimension with a deep trench isolation layer that penetrates through the substrate thickness, complementing the lateral isolation provided by the first and second device isolation layers. This three-dimensional isolation architecture effectively blocks cross-talk between pixel regions while maintaining manufacturing efficiency by using sequential deposition and etching processes that are standard in CMOS fabrication.
3Reliability
If deeper isolation trenches are created, then cross-talk is reduced, but the manufacturing process becomes more complex
Solution Approach 1:
The first device isolation layer, second device isolation layer, and trench isolation layer are merged to form an integrated deep device isolation structure. The first and second device isolation layers are formed using conformal deposition techniques that automatically adapt to the trench geometry, while the trench isolation layer is formed by etching and filling operations that align with the existing isolation structure. This merging approach achieves deep cross-talk prevention without significantly increasing manufacturing complexity, as all layers work together synergistically.
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 approach improves the integration density and manufacturing efficiency of CMOS image sensors by effectively isolating pixel regions and reducing cross-talk, leading to higher performance in image conversion and signal processing.
Implementation Method 1
forming an oxidized semiconductor layer by oxidizing a first portion of the semiconductor layer
Data Source
AI summary
An image sensor includes a substrate including a plurality of pixel regions, a first surface, and a second surface that is opposite to the first surface, and a deep device isolation pattern penetrating the substrate and between the plurality of pixel regions, the deep device isolation pattern including a first filling pattern adjacent to the second surface, a second filling pattern on the first filling pattern and adjacent to the first surface, a semiconductor pattern between the first filling pattern and the substrate, an oxidized semiconductor pattern on the semiconductor pattern and between the substrate and the second filling pattern, and a side insulating pattern between the semiconductor pattern and the substrate, where the semiconductor pattern directly contacts the oxidized semiconductor pattern.