Copper Plating Leveler for Uniform Surface Topography
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Solution Overview
Problem
Current copper plating chemistries struggle to achieve defect-free copper deposition with uniform surface topography across a wide range of feature dimensions and aspect ratios, particularly failing to produce flat or convex surfaces simultaneously for feature sizes from 10 μm to 150 μm at high deposition rates, which is crucial for semiconductor and MEMS applications.
Innovation Solution
Incorporation of quaternary ammonium salts of dialkylaminoalkyl esters of 10-thiaxanthenecarboxylic acid and its derivatives as levelers in the electrolytic copper plating chemistry, allowing for excellent leveling effects over a wide range of aspect ratios and high current densities, enabling the production of copper pillars and RDLs with flat or convex topography in a single bath composition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional copper plating chemistry is used, then copper deposition can be achieved, but uniform surface topography and flat/convex surfaces cannot be produced across a wide range of feature dimensions and aspect ratios
Solution Approach 1:
The patent develops a universal copper plating chemistry that can produce uniform surface topography and desired flat or convex surfaces across a wide range of feature dimensions (10-150 μm) and aspect ratios. The chemistry integrates multiple functional components including complexing agents, buffers, and surfactants that work synergistically to achieve consistent performance regardless of feature geometry, eliminating the need for multiple specialized chemistries.
Solution Approach 2:
The patent optimizes specific chemical parameters including pH range (2.5-4.5), complexing agent concentrations, and surfactant ratios to enable the plating chemistry to adapt to different feature dimensions and aspect ratios. By controlling these parameters, the chemistry achieves uniform surface topography and desired surface profiles across varying geometries while maintaining high deposition rates.
2Productivity
If high current densities are used to increase manufacturing throughput, then deposition rate increases, but leveling effect deteriorates
Solution Approach 1:
The patent formulates a plating chemistry that maintains effective leveling at high current densities (up to 10 ASD or 5 μm/min) by optimizing the concentration and type of levelers, surfactants, and complexing agents. The chemistry composition is specifically designed to prevent the deterioration of leveling effect that normally occurs at high deposition rates, enabling both high productivity and surface uniformity.
3Adaptability or versatility
If multiple copper plating chemistries are used to cover full range of feature dimensions, then all customer requirements can be met, but manufacturing cost increases
Solution Approach 1:
The patent creates a single universal copper plating chemistry that replaces multiple specialized chemistries, covering the full range of feature dimensions (10-150 μm) and aspect ratios. This consolidation eliminates the need for maintaining multiple chemical inventories, reduces process control complexity, and lowers manufacturing costs while meeting all customer requirements for different semiconductor device geometries.
4Reliability
If conventional plating chemistry is used, then deposition can occur, but defect-free copper lines cannot be achieved across varying aspect ratios
Solution Approach 1:
The patent develops a universal plating chemistry that delivers defect-free copper deposition across a wide range of aspect ratios by integrating optimized complexing agents, buffers, and surfactant systems. The chemistry maintains stable copper ion availability and controlled deposition kinetics regardless of feature geometry, preventing common defects such as dendrites, voids, and non-uniform thickness that plague conventional chemistries when applied to varying aspect ratios.
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 enables the production of copper pillars and RDLs with uniform surface morphology and high within-die uniformity, achieving deposition rates of up to 10 ASD (5 μm/min) across a wide range of feature sizes, significantly reducing manufacturing costs and increasing yield.
Implementation Method 1
electrolytic copper plating chemistry
Implementation Method 2
excellent leveling effects over a wide range of aspect ratios
Data Source
AI summary
The present disclosure relates to a leveling composition for electrodepositing metals. The composition comprises a compound of formula (I):