Semiconductor Device Trench Contact Alignment
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Solution Overview
Problem
The existing semiconductor devices with trench contact structures face issues with contact hole displacement due to alignment errors of the resist mask, leading to deteriorated electrical characteristics.
Innovation Solution
The semiconductor device incorporates a design with multiple trench portions and insulating layers, where contact holes are formed between the trench portions to expose insulators, allowing for precise alignment and minimizing displacement, thereby maintaining electrical integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a resist mask is used to form contact holes, then the contact holes can be formed at the region between trenches, but the contact holes may be displaced due to alignment error of the resist mask
Solution Approach 1:
The insulating layer protruding from the trench portions serves as a self-aligned reference structure that automatically defines the contact hole position. The contact holes are formed to expose these insulating layer protrusions, eliminating the need for external alignment references and making the structure self-correcting against alignment errors.
Solution Approach 2:
The insulating layer protrusions act as intermediary reference structures between the trenches and the contact holes. These protrusions provide a physical landmark that mediates the positioning relationship, ensuring accurate contact hole placement without direct reliance on resist mask alignment to the trenches.
2Reliability
If contact holes are formed between trenches, then electrical connection is achieved, but alignment errors cause displacement and deterioration of electrical characteristics
Solution Approach 1:
The insulating layer protrusions serve as self-aligned positioning references that automatically ensure correct contact hole placement. By forming contact holes that expose these protrusions, the structure itself provides the alignment information needed, making the process self-correcting and ensuring reliable electrical characteristics regardless of resist mask alignment variations.
3Manufacturing precision
If multiple trench portions with insulating layers are used, then contact hole displacement is suppressed, but the device structure becomes more complex
Solution Approach 1:
The insulating layer serves multiple functions: it provides electrical insulation within the trench, creates protruding positioning references on the trench surfaces, and defines the alignment landmarks for contact hole formation. This multi-functionality reduces the need for separate alignment structures, offsetting the increased complexity by consolidating multiple roles into a single component.
Data Source
AI summary
There is provided a semiconductor device including: a semiconductor layer including a main surface; a plurality of trenches including a plurality of first trench portions and a plurality of second trench portions, respectively; an insulating layer formed in an inner wall of each of the second trench portions; a first electrode buried in each of the second trench portions with the insulating layer interposed between the first electrode and each of the second trench portions; a plurality of insulators buried in the first trench portions so as to cover the first electrode; a contact hole formed at a region between the plurality of first trench portions in the semiconductor layer so as to expose the plurality of insulators; and a second electrode buried in the contact hole.