Semiconductor Device Dummy Active Region Stress Management
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Solution Overview
Problem
Semiconductor devices face stress issues due to narrow device isolation patterns, which affect the operating characteristics of MOS transistors, especially as they become more highly integrated, with stress varying across different regions of the substrate.
Innovation Solution
Incorporating a dummy active region and a guard ring region surrounding both active and dummy regions, with specific device isolation patterns to uniformly distribute physical stress across the substrate, ensuring consistent operating characteristics for MOS transistors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If device isolation patterns are made narrower to increase integration, then device integration is improved, but stress on the substrate and active regions increases
Solution Approach 1:
A dummy active region is introduced as an intermediary element between the active regions and the device isolation pattern. This dummy region acts as a stress-absorbing buffer that prevents the isolation pattern from directly stressing the active regions, thereby allowing narrow isolation patterns to be used for high integration without compromising substrate stress levels.
Solution Approach 2:
The dummy active region is designed as a copy or replica of the actual active region structure. By creating this identical structural copy and placing it adjacent to the active regions, the same stress characteristics are replicated in the dummy region, protecting the functional active regions from stress while maintaining the benefits of narrow isolation patterns.
2Productivity
If MOS transistors are concentrated within a predetermined region to increase density, then device density is improved, but stress uniformity across the region deteriorates
Solution Approach 1:
The dummy active regions are strategically placed at specific locations within the concentrated transistor region, particularly at the periphery where stress variations are most pronounced. This local placement creates zones of uniform stress distribution without requiring changes to the entire substrate, thereby maintaining high device density while achieving stress uniformity in critical areas.
Data Source
AI summary
A semiconductor device including a driving region and a dummy region disposed at both side of the driving region includes a semiconductor substrate having a plurality of active regions spaced from each by equal distances in the driving region, a dummy active region in the dummy region, and a guard ring region surrounding the active regions and the dummy active regions. The distance between the dummy active region and the active region nearest to the dummy active region is substantially the same as each distance between adjacent ones of the active regions, and is smaller than the distance between the dummy active region and a portion of the guard ring region nearest to the dummy active region.