Amorphous CoFeB Diffusion Barrier for Copper Interconnects
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Solution Overview
Problem
Copper, commonly used in semiconductor devices for its conductivity, faces issues with low thermo-dynamical stability, corrosion resistance, and diffusion into silicon, leading to leakage currents and device malfunctions, necessitating an effective diffusion barrier.
Innovation Solution
An amorphous trivalent material like CoFeB is used as a diffusion barrier layer in the damascene process to prevent copper diffusion, enhancing semiconductor device performance by forming a semiconductor device with a semiconductor substrate, interlayer dielectric layer, and copper interconnection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If copper is used as metal interconnection material, then conductivity and reliability are improved, but diffusion into silicon and thermo-dynamical stability deteriorate
Solution Approach 1:
A diffusion barrier layer composed of CoFeB amorphous alloy is introduced as an intermediary between the copper interconnection and the silicon substrate. This barrier layer effectively prevents copper atoms from diffusing into the silicon while maintaining electrical conductivity, thus resolving the contradiction between copper's excellent conductivity and its harmful diffusion effect.
Solution Approach 2:
The invention uses a composite material structure combining cobalt (Co), iron (Fe), and boron (B) in specific proportions to form the diffusion barrier layer. This composite amorphous alloy provides both effective copper diffusion barrier properties and good electrical conductivity, addressing the contradiction between blocking copper diffusion and maintaining electrical performance.
2Reliability
If copper is used as metal interconnection material, then conductivity is improved, but corrosion resistance and thermo-dynamical stability worsen
Solution Approach 1:
The CoFeB amorphous alloy diffusion barrier layer serves as a protective intermediary that shields the copper interconnection from corrosive environments and prevents thermo-dynamical instability. This barrier layer improves the overall corrosion resistance and thermo-dynamical stability while allowing copper to maintain its excellent conductivity properties.
3Reliability
If diffusion barrier layer is added to prevent copper diffusion, then reliability is improved, but device complexity increases
Solution Approach 1:
The invention optimizes the parameters of the diffusion barrier layer, including composition ratios (Co:Fe:B = 10-50:10-50:5-20 atomic ratio), thickness (50-200 nm), and amorphous structure, to achieve effective copper diffusion blocking with minimal impact on device complexity. By carefully controlling these parameters, the barrier layer provides reliable protection without significantly complicating the device structure.
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 amorphous CoFeB layer effectively inhibits copper diffusion, improving the reliability and conductivity of semiconductor devices by acting as a reliable barrier against electron and stress migration, while maintaining low production costs.
Implementation Method 1
an amorphous layer is used as a diffusion barrier for preventing diffusion of copper
Implementation Method 2
The amorphous CoFeB layer effectively inhibits copper diffusion, improving the reliability and conductivity of semiconductor devices by acting as a reliable barrier
Data Source
AI summary
A semiconductor device and a method of fabricating a semiconductor device is provided. The semiconductor device can include a semiconductor substrate; an interlayer dielectric layer having a damascene pattern formed on the semiconductor substrate; a diffusion barrier formed in the damascene pattern and made of a trivalent material; a seed layer formed on the diffusion barrier; and a copper interconnection formed on the seed layer. In one embodiment, the trivalent material is CoFeB.