Semiconductor Device Isolation Layer Segmentation for Leaning Defects
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Solution Overview
Problem
The process of forming device isolation layers in high-density image sensors is prone to defects such as leaning, which affects the integration density and electrical properties of semiconductor devices.
Innovation Solution
A semiconductor device design that includes a substrate with a device isolation layer defining light-receiving, light-blocking, and support regions, where the support regions are continuous with both light-receiving and light-blocking regions, and the device isolation layer extends through the substrate to provide an integral insulation structure, reducing the likelihood of defects like leaning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If device isolation layer is formed to define high-density regions, then integration density is improved, but manufacturing precision deteriorates due to leaning defects
Solution Approach 1:
The device isolation layer is segmented into a first device isolation layer and a second device isolation layer with different etch selectivities. The first layer has higher etch selectivity relative to the fill material, while the second layer has lower etch selectivity. This segmentation allows the formation of high-aspect-ratio isolation structures without leaning defects, enabling high integration density while maintaining manufacturing precision.
Solution Approach 2:
The etch selectivity parameter is changed between the first and second device isolation layers. By using materials with different etch selectivities relative to the fill material, the patent enables precise control over the isolation layer formation process, preventing leaning defects while achieving the required integration density.
2Quantity of substance
If device isolation layer is formed with high aspect ratio regions, then integration density is improved, but reliability deteriorates due to leaning defects
Solution Approach 1:
The device isolation layer is divided into two distinct layers with different etch selectivities. This segmentation enables the formation of high-aspect-ratio regions required for high integration density while preventing leaning defects that would compromise device reliability.
Solution Approach 2:
The patent uses composite material structure consisting of two different isolation layer materials with distinct etch selectivities relative to the fill material. This composite approach ensures both high integration density through high-aspect-ratio regions and high reliability by eliminating leaning defects.
3Device complexity
If single-layer device isolation structure is used, then device complexity is reduced, but manufacturing precision deteriorates due to leaning in high-density regions
Solution Approach 1:
Instead of using a single-layer isolation structure, the patent segments the isolation layer into two layers with different etch selectivities. This segmentation prevents leaning defects in high-density regions while maintaining reasonable device complexity through systematic material selection.
Data Source
AI summary
A semiconductor device includes a substrate having a first surface and a second surface opposite to the first surface. A device isolation layer which defines a first region, a second region, and a support region in the substrate. The second region has a smaller width than the first region, and the support region is between the first region and the second region. A photoelectric conversion element is in the first region. The support region is continuous with the first region and the second region. The device isolation layer has an integral insulation structure which extends through the substrate from the first surface of the substrate to the second surface of the substrate.