Inverted-T Isolation Pillar for Gate Contact Alignment
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Solution Overview
Problem
Current semiconductor technologies face challenges in achieving sufficient alignment and scaling of isolation structures for contacts to gates, sources, and drains, particularly at dimensions below 30 nm, which can lead to manufacturing failures and reduced device performance.
Innovation Solution
The implementation of a semiconductor device with a semiconductor substrate, isolation layer, active regions, and gate structures, where an isolation pillar with an inverted-T shape is formed between the active regions and gate structures, using high-κ materials and trimming techniques to enhance alignment and scaling of isolation structures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If self-aligned contacts are used to reduce device size, then device scaling is improved, but alignment precision deteriorates below 30 nm dimensions
Solution Approach 1:
The isolation pillar is formed in advance before contact hole formation, establishing precise alignment references (sidewalls) that guide subsequent contact formation. This preliminary structure ensures accurate contact alignment to gate, source, and drain even at dimensions below 30 nm where conventional self-aligned methods fail.
Solution Approach 2:
The isolation pillar acts as an intermediary structure between the conventional fabrication process and the final contact alignment. Its sidewalls serve as intermediate alignment references that enable precise contact formation without requiring direct self-alignment, thus resolving the alignment precision problem at scaled dimensions.
2Ease of manufacture
If conventional isolation structures are used, then manufacturing process is simple, but contact alignment reliability deteriorates at scaled dimensions
Solution Approach 1:
The isolation structure is segmented into two functional parts: a bulk isolation layer providing electrical isolation and an elevated isolation pillar providing alignment references. This segmentation allows each part to fulfill its specific function optimally, with the pillar sidewalls ensuring contact alignment reliability while the bulk layer maintains manufacturing simplicity.
Solution Approach 2:
The isolation structure is extended into the vertical dimension to create an elevated pillar, adding a new dimensional reference for alignment. This vertical extension provides sidewall references that improve contact alignment reliability without complicating the horizontal manufacturing process.
3Quantity of substance
If device dimensions are reduced to maintain Moore's Law, then device density is improved, but manufacturing failure risk increases
Solution Approach 1:
The isolation pillar sidewalls serve as self-aligned references that automatically guide contact formation without requiring additional alignment steps or complex lithography. This self-service alignment mechanism reduces manufacturing failure risk by eliminating alignment errors even as device dimensions are reduced to increase density.
Data Source
AI summary
A semiconductor device, comprising a semiconductor substrate; an isolation layer disposed on the semiconductor substrate; a first active region and a second active region disposed at least partially above the isolation layer; a first gate structure and a second gate structure disposed on the isolation layer, the first active region, and the second active region; and an isolation pillar disposed on the isolation layer, between the first and second active regions, and between and in contact with the first and second gate structures, wherein the isolation pillar has an inverted-T shape. A method for making the semiconductor device. A system configured to implement the method and manufacture the semiconductor device.