Stepped Interconnect Structure for Lower Contact Resistance
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Solution Overview
Problem
As semiconductor devices downscale, increasing contact lengths lead to higher contact resistance, which hampers high integration and low power consumption requirements.
Innovation Solution
A semiconductor device with a conductive insertion pattern formed between a lower wiring line and an upper via, utilizing a multilayer structure with specific materials like tungsten and cobalt, to reduce resistance and enhance connectivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If feature sizes are continuously decreased to achieve high integration, then integration density is improved, but contact length increases leading to higher contact resistance
Solution Approach 1:
The contact structure is divided into multiple segments: a lower contact plug, an intermediate conductive insertion pattern, and an upper contact plug. This segmentation allows each segment to be independently optimized, reducing the overall contact resistance by creating multiple shorter conductive paths instead of one long continuous path.
Solution Approach 2:
A conductive insertion pattern is introduced as an intermediary element between the lower contact plug and upper contact plug. This intermediate layer serves as a mediator that reduces the total contact length by creating a stepped configuration, thereby lowering the overall contact resistance while maintaining electrical connectivity.
2Productivity
If contact length increases due to downscaling, then integration is improved, but resistance increases reducing device performance
Solution Approach 1:
The contact structure transitions from a single vertical dimension to a multi-dimensional stepped configuration. By adding horizontal layers (conductive insertion pattern between lower and upper contacts), the patent creates a three-dimensional contact structure that reduces the effective vertical resistance path while maintaining the required integration level.
Solution Approach 2:
The contact structure uses composite material layers including different conductive materials (e.g., tungsten, cobalt, copper) with complementary properties. Each material is selected for its specific electrical and mechanical characteristics, creating a composite contact structure that optimizes both resistance and reliability.
Data Source
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AI summary
A semiconductor device includes a first conductive lower wiring disposed at a first metal level and that extends in a first direction, a first upper wiring structure connected to the first conductive lower wiring and that includes a first conductive upper wiring and a first conductive upper via, where the first conductive upper wiring is disposed at a second metal level higher than the first metal level and extends in a second direction different from the first direction, and a conductive insertion pattern disposed between the first conductive lower wiring and the first upper wiring structure and connected to the first conductive upper via. An upper surface of the conductive insertion pattern has a first width in the first direction, and a bottom surface of the first conductive upper via has a second width in the first direction that is less than the first width.