Nano-twinned Copper Circuit Layer via Electroplating and Annealing
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Solution Overview
Problem
Current copper wire manufacturing methods in integrated circuits face challenges with low electromigration resistance and mechanical properties, particularly in nanoscale wires, which affect the reliability of semiconductor devices, and existing methods to enhance this, such as adding other metals or using physical vapor deposition, are either costly or inefficient.
Innovation Solution
A method involving electroplating and annealing to form a nano-twinned copper circuit layer with preferred orientation and high twinned crystal density, which enhances electromigration resistance and mechanical properties, allowing for faster manufacturing and application in high-aspect-ratio structures like copper interconnects and through-silicon vias.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If physical vapor deposition is used to form twinned copper structure, then electromigration resistance capability is improved, but deposition time is lengthy and manufacturing efficiency deteriorates
Solution Approach 1:
The patent replaces physical vapor deposition (a physical/mechanical process) with electroplating (an electrochemical process) to form the copper circuit layer. This substitution enables faster deposition rates while maintaining the ability to create twinned copper structures with improved electromigration resistance, directly resolving the contradiction between reliability improvement and manufacturing efficiency.
Solution Approach 2:
The patent changes the deposition parameters by using electroplating instead of physical vapor deposition, and further optimizes the copper lattice orientation through controlled annealing processes. These parameter changes enable the formation of twinned copper structures with <100> orientation that achieve high electromigration resistance while significantly reducing manufacturing time and improving productivity.
2Reliability
If physical vapor deposition is used to form nanoscale twinned copper, then electromigration resistance is improved, but manufacturing cost increases
Solution Approach 1:
The patent substitutes physical vapor deposition with electroplating to form copper circuit layers. This replacement significantly reduces manufacturing costs while maintaining the capability to produce twinned copper structures with enhanced electromigration resistance, directly addressing the cost-effectiveness issue.
Solution Approach 2:
The patent employs a cost-effective electroplating process using readily available copper sources and standard electroplating equipment, replacing the expensive physical vapor deposition system. This approach achieves the desired twinned copper structure formation at lower material and equipment costs, making the process economically viable for industrial production.
3Reliability
If physical vapor deposition is used to form twinned copper, then copper wire electromigration resistance is improved, but the method cannot plate into vias or trenches having high aspect ratio
Solution Approach 1:
The patent replaces physical vapor deposition with electroplating, which uses electrochemical fields instead of physical vapor transport. This substitution enables effective plating into high aspect ratio vias and trenches through the self-aligning nature of electrochemical deposition, where copper ions are attracted directly to conductive surfaces regardless of geometry, achieving both high electromigration resistance and versatility for complex structures.
Solution Approach 2:
The patent introduces an electrochemical field as an intermediary mechanism to enable copper deposition in high aspect ratio structures. The electrochemical field acts as a mediator that guides copper ion transport and deposition, allowing uniform plating throughout complex geometries including deep vias and trenches, which cannot be achieved by physical vapor deposition methods.
4Reliability
If other metals or materials are added into copper wires to improve electromigration resistance, then reliability is improved, but contamination risk and manufacturing cost increase
Solution Approach 1:
The patent changes the approach from compositional modification (adding other metals) to structural modification (creating twinned copper lattice structures). By controlling the crystallographic orientation and twin boundary density of pure copper through electroplating and annealing parameters, the patent achieves enhanced electromigration resistance without introducing contaminating elements, maintaining material purity while improving performance.
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 method significantly improves the electromigration resistance and mechanical properties of copper wires, increasing the reliability of semiconductor products while reducing manufacturing time and costs compared to traditional physical vapor deposition methods.
Implementation Method 1
forming a Cu seeding layer in the openings; forming a nano-twinned Cu layer in the openings with an electroplating process
Implementation Method 2
annealing the substrate to transfer the material of the Cu seeding layer into nano-twinned Cu
Data Source
AI summary
A circuit board with twinned Cu circuit layer and a method for manufacturing the same are disclosed, wherein the method comprises the following steps: (A) providing a substrate with a first circuit layer formed thereon, wherein the first circuit layer comprises a conductive pad; (B) forming a first dielectric layer on the surface of the substrate; (C) forming plural openings in the first dielectric layer, wherein each opening penetrates through the first dielectric layer and communicates with the conductive pad to expose the conductive pad; (D) forming a Cu seeding layer in the openings; (E) forming a nano-twinned Cu layer in the openings with an electroplating process; and (F) annealing the substrate to transfer the material of the Cu seeding layer into nano-twinned Cu, wherein the nano-twinned Cu layer and the transferred Cu seeding layer are formed into a second circuit layer.