Varying-Depth Trench Isolation for Lower-Defect IC Fabrication
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Solution Overview
Problem
Conventional techniques for forming isolation trenches with varying depths in semiconductor devices are complex and prone to defects, which hinders the advancement of IC device technology and the demand for smaller device dimensions.
Innovation Solution
A semiconductor device structure featuring multiple trenches with varying depths, where each trench is lined with a dielectric liner and filled with a dielectric layer of specific materials, and a dielectric isolation structure with upper and lower sections in the second and third trenches, respectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple isolation trenches with varying depths are formed to improve device performance, then device performance is improved, but the fabrication process becomes complex and defect-prone
Solution Approach 1:
The fabrication process is segmented into distinct stages: forming shallow trenches first with dielectric liners and fill material, then forming deeper trenches that extend below the shallow trench bottoms. This segmentation allows each trench type to be optimized independently while simplifying the overall process by avoiding the need to form all varying-depth trenches in a single complex step.
Solution Approach 2:
The dielectric liners are formed in the shallow trenches before the deeper trenches are etched. This preliminary action provides a protective barrier and structural foundation that simplifies subsequent processing steps and reduces defects during the formation of varying-depth trenches.
2Reliability
If multiple isolation trenches with varying depths are formed to improve device performance, then device performance is improved, but the fabrication process becomes defect-prone
Solution Approach 1:
The trench formation is segmented into separate etching processes for shallow and deep trenches. This allows precise control over each trench depth independently, improving manufacturing precision by avoiding the complications of forming all varying depths in a single process step.
Solution Approach 2:
Dielectric liners are formed in shallow trenches before deeper trenches are etched. This preliminary protective layer prevents defects during subsequent processing and ensures precise trench formation by providing a stable reference structure.
Data Source
AI summary
The present disclosure generally relates to trench isolation structures for semiconductor devices. More particularly, the present disclosure relates to semiconductor devices having trench isolation structures with varying depths for electrically isolating integrated circuit (IC) components in the semiconductor devices. The present disclosure also relates to method of forming the trench isolation structures.