Deep Trench Isolation Layout for Void-Free Insulating Film Fill
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Solution Overview
Problem
In semiconductor device manufacturing, deep trench isolation (DTI) structures often result in voids due to incomplete filling of insulating film in corner areas, leading to metal residues and device faults.
Innovation Solution
The method involves revising the deep trench isolation layout using an optical proximity correction (OPC) process, which includes adding an assist feature to the outer corner and converting sharp angles to tilted angles, resulting in a slanted outer corner that facilitates complete gap-fill without voids.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a deep trench isolation structure with sharp corners is used, then the isolation effectiveness is improved, but voids are formed in corner areas during insulating film filling
Solution Approach 1:
The patent applies preliminary action by modifying the trench corner geometry before the insulating film filling process. The sharp corners are converted to slanted corners with a specific angle (e.g., 45 degrees) in advance, so that when the gap-fill process occurs, the insulating film can flow smoothly into the corner areas without forming voids. This pre-modification of the trench structure eliminates the root cause of the filling defect.
Solution Approach 2:
The patent changes the geometric parameter of the trench corner from a sharp angle (90 degrees) to a slanted angle (e.g., 45 degrees). This parameter change in the corner geometry fundamentally alters the flow dynamics of the insulating film during gap-fill, enabling complete filling without voids while preserving the isolation effectiveness of the deep trench structure.
2Manufacturing precision
If optical proximity correction is applied to create slanted outer corners, then void formation is eliminated, but the layout complexity increases
Solution Approach 1:
The patent applies local quality by making a specific modification only to the outer corner regions of the isolation trenches, while leaving the rest of the layout unchanged. The OPC process selectively alters only the problematic corner areas to have slanted geometry, rather than redesigning the entire layout. This localized approach eliminates voids at critical locations without unnecessarily increasing overall layout complexity.
Data Source
AI summary
A deep trench layout implementation for a semiconductor device is provided. The semiconductor device includes an isolation film with a shallow depth, an active area, and a gate electrode formed in a substrate; a deep trench isolation surrounding the gate electrode and having one or more trench corners; and a gap-fill insulating film formed inside the deep trench isolation. The one or more trench corners is formed in a slanted shape from a top view.