Copper Electroplating Bath Imidazole Bisepoxide Morphology
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Solution Overview
Problem
Current copper electroplating methods for photoresist defined features, such as copper pillars and redistribution layer wiring, often result in non-uniform surface morphology, leading to defects and performance issues in advanced packaging technologies.
Innovation Solution
A copper electroplating method using a bath containing reaction products of imidazole and bisepoxide compounds, along with electrolytes, accelerators, and suppressors, to achieve copper photoresist features with a substantially uniform surface morphology, characterized by an average %TIR of 5% to 8% and %WID of 5% to 12%, ensuring smooth and flat profiles without nodules.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional copper electroplating methods are used, then copper features can be formed, but the surface morphology is non-uniform leading to defects
Solution Approach 1:
The patent modifies the electroplating bath chemistry by incorporating imidazole and bisepoxide compounds, which change the deposition parameters to achieve uniform surface morphology with %TIR of 5-15 micrometers and eliminate nodular defects, thereby resolving the contradiction between manufacturing precision and reliability
Solution Approach 2:
The electroplating bath uses a composite chemical system combining imidazole compounds, bisepoxide compounds, and conventional plating additives, creating a synergistic effect that produces uniform copper deposits with controlled morphology and eliminates surface defects
2Productivity
If high deposition rates are used to enable high wafer throughput, then productivity increases, but surface uniformity deteriorates
Solution Approach 1:
The imidazole-bisepoxide chemistry enables high deposition rates while maintaining surface uniformity by modifying the nucleation and growth kinetics of copper deposits, allowing fast plating without sacrificing morphological quality
3Ease of manufacture
If conventional electroplating chemistry is used, then the process is simple, but the pillar shape is non-flat and morphology is poor
Solution Approach 1:
The addition of imidazole and bisepoxide compounds to the electroplating bath changes the deposition parameters to achieve flat pillar tops and uniform cylindrical shapes, transforming the morphology outcome while maintaining process simplicity
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 provides copper photoresist features with a uniform morphology, enhancing the reliability and performance of copper pillars and bond pads by maintaining a balance between %TIR and %WID, thereby improving the quality of copper electroplating processes for advanced packaging applications.
Implementation Method 1
The substrate including the layer of photoresist is immersed in the copper electroplating bath and copper is electroplated in the circuit line pattern or aperture to form features such as pillars, bond pads or circuit lines
Data Source
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AI summary
Electroplating methods enable the plating of photoresist defined features which have substantially uniform morphology. The electroplating methods include copper electroplating baths with reaction products of imidazole and bisepoxides to electroplate the photoresist defined features. Such features include pillars, bond pads and line space features.