Cu Interconnect HEA Barrier and Seed Layer Co-Formation
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Solution Overview
Problem
Current copper interconnects face issues with complex process flows, high production costs, and low efficiency due to the need for separate deposition of diffusion barriers and copper seed layers, which also result in poor thermal stability and adhesion.
Innovation Solution
A method involving the simultaneous formation of a self-formed high-entropy alloy diffusion barrier and copper seed layer through co-deposition and annealing, using physical vapor deposition and rapid thermal annealing, to create a Cu interconnect with improved thermal stability and adhesion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If separate deposition processes are used for diffusion barrier and copper seed layer, then each layer can be optimized independently, but the process flow becomes complex and production cost increases
Solution Approach 1:
The patent combines the diffusion barrier layer and copper seed layer into a single high-entropy alloy layer that performs both functions simultaneously. The co-deposition process deposits all five metal elements (Ti, V, Cr, Mn, Fe) together in one step, eliminating the need for separate deposition processes while maintaining the protective and conductive functions required for copper interconnects.
Solution Approach 2:
The high-entropy alloy layer serves multiple functions simultaneously: it acts as a diffusion barrier to prevent copper migration, provides a seed layer for subsequent copper electroplating, and offers thermal stability and mechanical strength. This multi-functional design replaces traditional multi-layer structures with a single versatile material system.
2Reliability
If multiple deposition steps are performed for barrier layer and seed layer, then adhesion can be improved, but production efficiency decreases and cost increases
Solution Approach 1:
The patent merges the barrier layer and seed layer deposition into a single co-deposition step, reducing production time and increasing efficiency. The high-entropy alloy composition (Ti-V-Cr-Mn-Fe) is designed to provide inherent adhesion properties to silicon substrates while maintaining barrier functionality, achieving good adhesion without requiring multiple sequential deposition steps.
3Object-affected harmful factors
If traditional PVD barrier layer is used, then diffusion protection is provided, but thermal stability and adhesion are insufficient
Solution Approach 1:
The patent employs a high-entropy alloy composite material consisting of five metal elements (Ti, V, Cr, Mn, Fe) in specific proportions. This composite material provides superior thermal stability compared to traditional single-element or bi-element barrier layers, while maintaining effective diffusion protection. The synergistic interaction between the five elements creates a stable crystalline structure that resists thermal degradation and copper diffusion.
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
This approach simplifies the process, reduces costs, and achieves a thin, efficient diffusion barrier with high adhesion and thermal stability, suitable for micro-electronic applications.
Implementation Method 1
annealing the co-deposition material layer to simultaneously and automatically form the diffusion barrier formed with the self-formed high-entropy alloy and the Cu seed layer
Implementation Method 2
the step of annealing the co-deposition material layer may be performed with a quick annealing furnace for rapid thermal annealing
Implementation Method 3
performing physical vapor deposition to co-deposit a membrane at the pre-depositing area with a high-entropy target and the Cu target
Implementation Method 4
electroplating the Cu seed layer to form a Cu electroplating layer to prepare the Cu interconnect
Data Source
AI summary
A Cu interconnect having a diffusion barrier formed with the self-formed high-entropy alloy a method of preparing the same are provided. A high-entropy alloy and Cu are deposited together. When annealing, a diffusion barrier is formed through segregation of the high-entropy alloy may, toward a bottom and a sidewall of an interconnect via, and a Cu seed layer is formed through segregation of Cu at an outer surface of the diffusion barrier, so as to simultaneously self-form the diffusion barrier formed with the self-formed high-entropy alloy and the Cu seed layer. The Cu interconnect having a diffusion barrier formed with the self-formed high-entropy alloy comprises: a base, the self-formed diffusion barrier formed with the self-formed high-entropy alloy and the Cu seed layer and a Cu electroplating layer electroplating on the Cu seed layer.