Copper Electroplating Composition for 3D Via Filling
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Solution Overview
Problem
Current electroplating compositions for filling through-vias in three-dimensional integrated circuits are aggressive to seed and barrier layers, leading to incomplete filling and contamination issues, such as the presence of carbon, chlorine, and sulfur, which affect the reliability and performance of microelectronic devices.
Innovation Solution
A pH-neutral or slightly acidic electroplating composition based on a mixture of copper, ethylenediamine, ammonium sulfate, and thiodiglycolic acid, which is less aggressive to seed and barrier layers, minimizing contaminant generation and ensuring uniform copper deposition across high-aspect-ratio vias.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If current electroplating compositions are used to fill through-vias, then copper deposition occurs, but seed and barrier layers are damaged and contaminants are generated
Solution Approach 1:
The patent changes the chemical parameters of the electroplating composition by using pH-neutral or slightly acidic conditions instead of highly acidic compositions, and by selecting specific copper salts and complexing agents that minimize aggression toward seed and barrier layers while maintaining effective copper deposition
Solution Approach 2:
The patent introduces benign organic acids (such as acetic acid, formic acid, or citric acid) as intermediaries to control the electroplating process, providing a less aggressive chemical environment that protects seed and barrier layers while still enabling copper deposition through controlled complexation
2Productivity
If current electroplating compositions are used to fill through-vias, then copper filling occurs, but contaminants such as carbon, chlorine, and sulfur are generated
Solution Approach 1:
The patent changes the compositional parameters by eliminating or minimizing sources of carbon, chlorine, and sulfur contaminants, using copper salts and complexing agents that do not introduce these elements, thereby achieving contaminant-free copper deposition while maintaining filling efficiency
Solution Approach 2:
The patent converts the potential harm of aggressive electroplating compositions that cause contaminant generation into a benefit by using controlled, mild compositions that achieve complete via filling without introducing contaminants, turning a previously harmful process into a clean deposition method
3Speed
If aggressive electroplating compositions are used, then copper deposition speed increases, but seed and barrier layers are compromised
Solution Approach 1:
The patent applies dynamic control of the electroplating process by using pH-neutral or slightly acidic conditions with controlled complexing agents that allow the deposition rate to be optimized without compromising layer integrity, creating a dynamic balance between speed and reliability
Solution Approach 2:
The patent employs periodic or controlled addition of copper ions and complexing agents during the electroplating process, maintaining optimal conditions for fast deposition while periodically monitoring and adjusting parameters to prevent damage to seed and barrier layers
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 composition effectively fills high-aspect-ratio vias without material defects, reduces contaminant generation, and enhances the reliability and performance of microelectronic devices by maintaining the integrity of seed and barrier layers, ensuring excellent copper deposition with minimal voids and overburden.
Implementation Method 1
an electroplating composition intended for filling, by the electroplating of copper, a cavity in a semiconductor substrate
Implementation Method 2
a complexing agent for the copper comprising at least one compound chosen from aliphatic polyamines having 2 to 4 amino groups
Data Source
Figure 1~2
Figure 3~4
Figure 5~6A
AI summary
The subject-matter of the present invention is a composition especially intended for filling, by the electroplating of copper, a cavity in a semiconductor substrate such as a "through-via" structure for the production of interconnects in three-dimensional integrated circuits. According to the invention, this composition comprises in solution in a solvent: - copper ions in a concentration lying between 45 and 1500 mM; - a complexing agent for the copper consisting of at least one compound chosen from aliphatic polyamines having 2 to 4 amino groups, preferably ethylenediamine, in a concentration lying between 45 and 3000 mM; - the molar ratio between the copper and said complexing agent lying between 0.1 and 5; - thiodiglycolic acid in a concentration lying between 1 and 500 mg/l; and - optionally a buffer system, in particular ammonium sulfate, in a concentration lying between 0.1 and 3M. Application: fabrication of three-dimensional integrated circuits for the electronics industry.