Stepped Backside Via Contact Structure for Short-Resistant IC Wiring
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Solution Overview
Problem
As integrated circuit devices are downscaled, there is a need for a stable and optimized wiring structure to prevent unintended short-circuits between conductive regions, which existing technologies fail to address effectively due to reduced insulating distances and increased complexity.
Innovation Solution
The integration of a backside insulating structure with an etch stop pattern, overlapping gate lines, source/drain regions, and a backside via contact with a stepped portion, which includes different materials and configurations to maintain sufficient insulating distances and prevent short-circuits, even in reduced areas.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If integrated circuit devices are downscaled to improve integration density, then productivity and integration density are improved, but the insulating distance between conductive regions is reduced, leading to increased risk of short-circuits and decreased reliability
Solution Approach 1:
The patent introduces a stepped portion in the backside via contact that creates a horizontal offset between adjacent via contacts. This dimensional change from vertical alignment to horizontal staggering increases the effective insulating distance between conductive regions without increasing the overall device footprint, thereby maintaining high integration density while improving reliability
Solution Approach 2:
The stepped portion acts as an intermediary structural feature between via contacts to different source/drain regions. By introducing this intermediate horizontal level, the patent effectively increases the spacing between conductive paths without requiring larger insulating materials or changing the fundamental via contact function
2Reliability
If the insulating distance is increased to prevent short-circuits, then reliability is improved, but the wiring structure becomes more complex and device area increases
Solution Approach 1:
The stepped portion is introduced only in specific locations where via contacts need to be staggered, rather than uniformly across the entire device. This localized structural modification increases spacing only where necessary to prevent short-circuits, while maintaining simple wiring structures in other areas where high spacing is not required
3Reliability
If the insulating distance is increased to prevent short-circuits, then reliability is improved, but the device area increases
Solution Approach 1:
The patent resolves the area-reliability contradiction by utilizing the horizontal dimension through stepped portions. Instead of increasing vertical or lateral spacing that would expand device area, the invention staggers via contacts in the horizontal plane at different depth levels, effectively increasing insulation distance within the same footprint
Data Source
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AI summary
An integrated circuit device includes a backside insulating structure including an etch stop pattern, gate lines arranged over the backside insulating structure and each overlapping the etch stop pattern in a vertical direction, source/drain regions respectively arranged one-by-one between the gate lines, and a backside via contact passing through the etch stop pattern in the vertical direction and connected to a first source/drain region selected from the source/drain regions, wherein the backside via contact includes a stepped portion, which is apart from a first vertical level in the vertical direction by as much as a first distance and has a change in the width of the backside via contact in a horizontal direction at a second vertical level that is adjacent to the etch stop pattern, the first vertical level being closest to the plurality of gate lines in the backside insulating structure.