Tapered DC Plug for Low Resistance and Insulation
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Solution Overview
Problem
The miniaturization of semiconductor devices has led to challenges in reducing the resistance of direct contact (DC) plugs and ensuring electrical insulation from adjacent contact plugs, which existing techniques have not effectively addressed.
Innovation Solution
A semiconductor device design featuring a direct contact (DC) structure with a conductive DC plug and insulating spacers, where the DC plug has a tapered side surface and varying widths, and is confined within a DC hole with a lower DC plug and an upper DC plug, allowing for reduced contact resistance and effective insulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the DC plug is miniaturized to reduce device size, then device scaling is improved, but contact resistance increases and electrical insulation becomes difficult to maintain
Solution Approach 1:
The DC plug is divided into multiple segments with different cross-sectional areas along its length. The upper portion has a larger cross-sectional area than the lower portion, allowing the plug to maintain low contact resistance at the contact interface while fitting within miniaturized device structures. This segmentation enables the plug to satisfy both size reduction and electrical performance requirements simultaneously.
2Reliability
If the DC plug cross-sectional area is increased to reduce contact resistance, then contact resistance decreases, but device miniaturization is hindered
Solution Approach 1:
The DC plug exhibits non-uniform cross-sectional area along its length, with the upper portion having a larger area than the lower portion. This local quality variation allows the plug to have sufficient contact area at the critical contact interface to minimize resistance, while the overall plug volume remains constrained for device miniaturization. The cross-sectional area is optimized locally where it matters most for electrical performance.
3Productivity
If adjacent contact plugs are placed closer to increase device density, then device integration is improved, but electrical insulation between plugs becomes difficult to maintain
Solution Approach 1:
Instead of increasing the spacing between adjacent contact plugs to maintain insulation, this invention inverts the approach by enlarging the upper portion of each DC plug. The larger upper cross-sectional area provides better electrical insulation between adjacent plugs at the upper level where bit lines are formed, while the lower portion remains compact for high-density integration. This inversion allows closer spacing of plugs while maintaining insulation through the enlarged upper sections.
Data Source
AI summary
A semiconductor device includes an interlayer insulating layer on a substrate, and a direct contact (DC) structure vertically penetrating the interlayer insulating layer and contacting the substrate, the DC structure including a DC hole exposing the substrate, an insulating DC spacer on an inner wall of the DC hole, and a conductive DC plug on the DC spacer and filling the DC hole, the DC plug including a lower DC plug and an upper DC plug on the lower DC plug, the lower DC plug having a smaller horizontal width than that of the upper DC plug.