CuMn Alloy Sputtering Target for Uniform Semiconductor Wiring
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Solution Overview
Problem
The challenge is to form a semiconductor copper alloy wiring with excellent uniformity and reduced in-plane variation to improve yield and reliability, while preventing copper diffusion contamination and enhancing electron migration and corrosion resistance.
Innovation Solution
A high-purity copper-manganese-alloy sputtering target with 0.05 to 20 wt% Mn, controlled in-plane variation in Mn concentration, Vickers hardness, electrical conductivity, and thermal conductivity to ensure uniform film formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional diffusion barrier layer of Ta or TaN is used, then copper diffusion contamination is prevented, but with progress in miniaturization the barrier layer cannot sufficiently prevent copper diffusion
Solution Approach 1:
The patent uses a composite barrier layer structure consisting of a CuMn alloy layer and a Ta/TaN diffusion barrier layer. The CuMn alloy layer reacts with oxygen to form MnOx that precipitates at grain boundaries, creating a dual-mechanism barrier system that combines chemical precipitation with physical barrier properties, providing effective copper diffusion prevention even in miniaturized structures
Solution Approach 2:
The patent modifies the copper wiring material by adding manganese (0.01-10 wt%) to create a CuMn alloy with specific compositional parameters. This parameter change enables the alloy to form a self-organizing barrier layer with controlled MnOx precipitation, transforming the material properties to achieve better diffusion prevention than pure copper or conventional barrier layers alone
2Reliability
If in-plane variation in thickness or sheet resistance is reduced, then yield of chips is improved, but achieving uniform film formation requires precise control of sputtering target properties
Solution Approach 1:
The patent ensures homogeneity by controlling the sputtering target to have uniform Mn concentration distribution (in-plane variation ≤5%). The CuMn alloy target is designed with homogeneous composition and controlled crystal grain structure, which translates to uniform film formation with consistent thickness and sheet resistance across the wafer surface, directly improving chip yield
Solution Approach 2:
The patent controls specific parameters of the sputtering target including Mn concentration (0.01-10 wt%), in-plane variation of Mn concentration (≤5%), and crystal grain size (average 1-100 μm with in-plane variation ≤20%). These parameter controls ensure that the deposited film has uniform thickness and electrical properties, reducing in-plane variation and improving manufacturing precision
3Reliability
If high-purity copper is used, then electrical conductivity is improved, but copper is very active and easily diffuses causing contamination
Solution Approach 1:
The CuMn alloy performs self-service by automatically forming a protective barrier layer through in-situ reaction during the sputtering process. The manganese in the alloy reacts with oxygen from the insulating film or atmosphere to form MnOx that precipitates at grain boundaries, creating a self-organizing barrier that prevents copper diffusion without requiring external intervention or additional processing steps
Solution Approach 2:
The patent creates a composite structure where CuMn alloy grains are embedded in a matrix of MnOx precipitation at grain boundaries. This composite microstructure combines the high electrical conductivity of copper grains with the diffusion-blocking properties of the oxide boundary layer, achieving both low resistance and contamination prevention
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 achieves uniform thin film thickness, improved semiconductor product yield, and enhanced self-diffusion suppression, electron migration resistance, and corrosion resistance.
Implementation Method 1
a high-purity copper-manganese-alloy sputtering target that can form a thin film having excellent uniformity
Data Source
AI summary
Provided is a high-purity copper-manganese-alloy sputtering target comprising 0.05 to 20 wt% of Mn and the remainder being Cu and inevitable impurities. The high-purity copper-manganese-alloy sputtering target is characterized in that the in-plane variation (CV value) in Mn concentration of the target is 3% or less. It is thus possible to form a thin film having excellent uniformity by adding an appropriate amount of a Mn element to copper and reducing the in-plane variation of the sputtering target. In particular, there is provided a high-purity copper-manganese-alloy sputtering target which is useful for improving the yield and the reliability of semiconductor products which are making progress in a degree of refinement and integration.