Copper Plating Bath Composition for Uniform TSV And Damascene Filling
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Solution Overview
Problem
Existing electrodeposition processes for copper in electronic circuits face challenges in achieving uniform and conformal deposition in submicron features and through silicon vias, with issues such as high impurity levels and non-uniform film thickness, particularly in dielectric and semiconductor structures.
Innovation Solution
The use of quaternized poly(epihalohydrin) in electrolytic plating baths, combined with copper ions, acid, and suppressors, to enhance the properties of copper deposition, ensuring compatibility and uniformity in various applications, including Damascene processes and through silicon vias, by promoting a vertical polarization gradient and high throwing power.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional electrodeposition processes are used for copper deposition in submicron features and through silicon vias, then copper can be deposited on the substrate, but the film thickness is non-uniform and impurity levels are high
Solution Approach 1:
The patent applies parameter changes by modifying the chemical composition parameters of the electrolyte, specifically incorporating quaternized poly(epihalohydrin) levelers and accelerators at controlled concentrations. This changes the electrochemical parameters of the deposition process to achieve uniform film thickness and reduce impurities in submicron features and through silicon vias
Solution Approach 2:
The patent uses composite materials by combining multiple electrolyte components including quaternized poly(epihalohydrin) levelers, accelerators, and other additives in specific ratios. This composite electrolyte formulation works synergistically to improve deposition uniformity and reduce impurity levels simultaneously
2Manufacturing precision
If conventional plating baths are used for conformal plating of through holes and surrounding field, then copper deposition occurs, but throwing power is insufficient leading to non-conformal deposits
Solution Approach 1:
The patent changes the chemical parameters of the plating bath by incorporating specific concentrations of quaternized poly(epihalohydrin) levelers and accelerators. This modifies the electrochemical window and polarization characteristics to enhance throwing power and achieve conformal plating distribution in through holes and surrounding fields
Solution Approach 2:
The quaternized poly(epihalohydrin) compounds act as intermediary substances that mediate between the copper ions and the substrate surface. These levelers and accelerators control the current distribution and deposition kinetics, enabling conformal plating by acting as chemical mediators in the electrochemical process
3Ease of manufacture
If simple electrolyte compositions are used for copper deposition, then the process is simple, but deposition uniformity in complex features like TSVs and Damascene structures is poor
Solution Approach 1:
The patent applies universality by designing a multi-functional electrolyte composition where quaternized poly(epihalohydrin) compounds serve multiple functions simultaneously: they act as levelers to control deposition uniformity, accelerators to enhance deposition rate, and impurity suppressors. This single additive system addresses multiple deposition challenges in complex features like TSVs and Damascene structures
Solution Approach 2:
The patent uses composite materials by formulating a complex electrolyte mixture containing quaternized poly(epihalohydrin) levelers, accelerators, and other additives in specific proportions. This composite formulation provides synergistic effects that achieve uniform deposition in complex three-dimensional features while maintaining process simplicity through a single bath formulation
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 copper film thickness and high throwing power, ensuring planarity and conformal plating over dielectric surfaces, reducing impurities and voids, and enabling simultaneous deposition in complex features like through silicon vias and printed circuit boards.
Implementation Method 1
the function of the additives is to establish a vertical polarization gradient along the wall of a via or trench which enhances the current density at the bottom relative to the current density in the upper reaches of the wall and on the field
Implementation Method 2
supplying electrical current to the electrolytic deposition composition to deposit copper on the substrate
Data Source
AI summary
An aqueous electrolytic composition and a process for electrodeposition of copper on a dielectric or semiconductor base structure using the aqueous electrolytic composition. The process includes (i) contacting a metalizing substrate comprising a seminal conductive layer on the base structure with an aqueous electrolytic deposition composition; and (ii) supplying electrical current to the electrolytic deposition composition to deposit copper on the substrate. The aqueous electrolytic composition comprises: (a) copper ions; (b) an acid; (c) a suppressor; and (d) a quaternized poly(epihalohydrin) comprising n repeating units corresponding to structure 1N and p repeating units corresponding to structure 1P: