Shield Via Plug for Copper Diffusion Control in Semiconductor Devices
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Solution Overview
Problem
Copper layers in semiconductor devices suffer from electromigration, leading to diffusion issues and potential short circuits between conductive layers, particularly at the interface between the stopper layer and the interlayer insulating layer, which complicates their use as interconnection lines.
Innovation Solution
A semiconductor device design incorporating a shield via plug with a conductive layer and a via insulating layer, positioned between conductive structures to prevent copper atom diffusion by cutting through the interface between the stopper layer and the interlayer insulating layer, thereby reducing the risk of short circuits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a copper layer is used as a conductive layer for interconnection lines, then low electric resistance is achieved, but electromigration phenomena occur leading to copper atom diffusion and potential short circuits
Solution Approach 1:
A shield via plug is introduced as an intermediary structure between copper-containing conductive layers. This shield via plug penetrates through the interface between the stopper layer and interlayer insulating layer, acting as a barrier that blocks copper atom diffusion paths while allowing the copper layer to maintain its low-resistance electrical connection function
Solution Approach 2:
The shield via plug is positioned to segment the continuous interface between the stopper layer and interlayer insulating layer. By creating discrete barrier points at critical diffusion interfaces, the structure divides the diffusion path into isolated segments, preventing copper atoms from migrating across the entire interface
2Adaptability or versatility
If copper atoms are allowed to diffuse through the interface between stopper layer and interlayer insulating layer, then electromigration is tolerated, but short circuits between conductive layers occur
Solution Approach 1:
The shield via plug serves as a mediating barrier structure that selectively blocks copper atom diffusion while permitting electrical isolation to be maintained. It is positioned at the critical interface region to prevent copper migration into adjacent insulating layers and conductive structures, thereby preserving conductive layer isolation
3Ease of manufacture
If the interface between stopper layer and interlayer insulating layer is left unprotected, then manufacturing simplicity is maintained, but copper atom diffusion occurs
Solution Approach 1:
The shield via plug is integrated into the existing via structure and filled with conductive material using standard semiconductor manufacturing processes. This approach adds minimal manufacturing complexity while effectively preventing copper diffusion at the stopper layer interface
Solution Approach 2:
The shield via plug structure is formed in advance during the via formation process, before copper deposition occurs. This preliminary structural preparation ensures that the diffusion barrier is already in place to prevent copper migration, rather than requiring additional post-copper processing steps
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution effectively suppresses copper atom diffusion, preventing short circuits and enhancing the reliability of copper-containing conductive layers in semiconductor devices by maintaining the integrity of the interface between the stopper and insulating layers.
Implementation Method 1
copper atoms from being diffused through an interface between a stopper layer and an interlayer insulating layer
Data Source
AI summary
A semiconductor device includes a lower interlayer insulating layer, a first stopper layer, and an upper interlayer insulating layer sequentially stacked on a substrate. First and second lower conductive layers, which are laterally separated from each other, are provided in the lower interlayer insulating layer. First and second upper via plugs are connected to the first and second lower conductive layers, respectively, through the upper interlayer insulating layer and the first stopper layer. Further, between the first and second upper via plugs, at least one line-shaped shield via plug extends into the lower interlayer insulating layer through the first stopper layer. The shield via plug is in an electrically-floating state.