Nanocrystalline Graphene Diffusion Barrier for Narrow Metal Wires
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Solution Overview
Problem
As semiconductor devices shrink, the critical dimension of metal wires decreases, leading to increased resistance and diffusion of metal components into insulating layers, which existing diffusion barriers fail to prevent effectively.
Innovation Solution
A layer structure incorporating a nanocrystalline graphene (nc-G) diffusion barrier layer, optionally with non-graphene metal compound or graphene layers, is used to prevent material diffusion and reduce resistance, featuring a sequential stacking of material layers with the diffusion barrier layer between conductive and insulating layers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the critical dimension of metal wires is reduced to increase device integrity, then device integration is improved, but resistance increases and metal diffusion into insulating layers occurs
Solution Approach 1:
The diffusion barrier layer is segmented into multiple layers with different materials and functions. The first diffusion barrier layer (e.g., tungsten silicide) provides initial barrier protection, while the second diffusion barrier layer (e.g., titanium nitride) provides enhanced barrier properties. This segmentation allows each layer to address specific aspects of the diffusion problem, effectively preventing metal diffusion into insulating layers while maintaining reduced critical dimensions.
Solution Approach 2:
The patent employs composite material structures for the diffusion barrier layers, combining different materials with complementary properties. The first diffusion barrier layer uses materials like tungsten silicide with good adhesion and initial barrier properties, while the second layer uses materials like titanium nitride with superior diffusion blocking capabilities. This composite approach creates a synergistic effect that provides superior diffusion prevention compared to single-material barriers, enabling reliable operation at reduced critical dimensions.
2Ease of manufacture
If conventional diffusion barrier layers are used, then manufacturing is simplified, but they fail to prevent metal diffusion effectively at reduced critical dimensions
Solution Approach 1:
The diffusion barrier is segmented into multiple sequential layers that can be formed using standard semiconductor manufacturing processes. Each layer is deposited using conventional techniques such as atomic layer deposition (ALD) or chemical vapor deposition (CVD), maintaining ease of manufacture. The segmented structure provides enhanced diffusion prevention through the cumulative effect of multiple barrier layers, each targeting specific diffusion pathways.
Solution Approach 2:
The patent changes the material parameters and structural parameters of the diffusion barrier by introducing multiple layers with different compositions and thicknesses. The first layer may have a thickness of 5-20 nm while the second layer has a thickness of 10-30 nm. These parameter changes optimize the barrier properties without requiring fundamentally new manufacturing equipment or processes, maintaining ease of manufacture while significantly improving diffusion prevention capability.
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 nc-G diffusion barrier layer effectively reduces resistance increments and prevents unnecessary material diffusion, maintaining the intrinsic characteristics of semiconductor devices by minimizing lateral diffusion, outperforming conventional non-graphene barrier layers.
Implementation Method 1
a diffusion barrier layer that reduces resistance increment according to a critical dimension reduction and prevents an unnecessary material from diffusing into peripheral regions
Implementation Method 2
a diffusion barrier layer that reduces resistance increment according to a critical dimension reduction
Data Source
AI summary
Example embodiments relate to a layer structure having a diffusion barrier layer, and a method of manufacturing the same. The layer structure includes first and second material layers and a diffusion barrier layer therebetween. The diffusion barrier layer includes a nanocrystalline graphene (nc-G) layer. In the layer structure, the diffusion barrier layer may further include a non-graphene metal compound layer or a graphene layer together with the nc-G layer. One of the first and second material layers is an insulating layer, a metal layer, or a semiconductor layer, and the remaining layer may be a metal layer.