Amine-Polyacrylamide Levelers for Copper Electroplating
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Solution Overview
Problem
Current copper electroplating baths struggle to achieve uniform copper deposits on substrates with irregular topography, particularly in areas with both through-holes and blind vias, due to inadequate throwing power and excessive nodule formation.
Innovation Solution
The use of reaction products of amines and polyacrylamides as leveling agents in copper electroplating baths, which enhance throwing power and reduce nodule formation by providing a substantially level copper layer across substrates with varied feature sizes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional leveling agents are used in copper electroplating baths, then copper deposit uniformity is improved, but throwing power remains insufficient
Solution Approach 1:
The patent modifies the chemical parameters of the leveling agent by using reaction products of amines with specific structures (containing heterocyclic rings, sulfonamide groups, or carboxylic acid groups) and polyacrylamides with controlled molecular weights and compositions. These parameter changes in the leveling agent's chemical structure enable simultaneous improvement of copper deposit uniformity and throwing power, resolving the contradiction between manufacturing precision and reliability.
2Quantity of substance
If electroplating is performed on substrates with irregular topography including blind vias and through-holes, then via filling is achieved, but voltage drop causes uneven metal deposit
Solution Approach 1:
The patent applies local quality by designing leveling agents that can selectively adsorb onto different surface features (via walls, through-hole surfaces, and substrate planes) with different affinities. The amine-polyacrylamide reaction products possess functional groups that interact differently with various surface geometries, enabling localized control of copper deposition rates to achieve uniform metal layers despite irregular substrate topography.
Solution Approach 2:
The leveling agent acts as an intermediary substance between the copper ions in the electroplating bath and the substrate surface. The amine-polyacrylamide reaction products mediate the copper deposition process by adsorbing onto the substrate and modifying the local electrochemical environment, thereby controlling copper ion reduction rates at different surface locations to achieve uniform via filling and surface plating.
3Reliability
If current leveling agents are used to maximize via filling, then through-hole center copper deposit increases, but thickness variation between vias and substrate surface persists
Solution Approach 1:
The patent employs composite material principles by creating reaction products that combine amine molecules with specific functional groups (heterocyclic rings, sulfonamide, or carboxylic acid groups) and polyacrylamide polymers. This composite chemical structure provides multiple interaction mechanisms with the substrate and copper ions, enabling simultaneous achievement of high throwing power (via filling) and minimal thickness variation between different surface features.
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 described method effectively deposits copper with high throwing power and reduced nodules, ensuring uniform thickness across substrates, including those with small features and varied aperture sizes, thereby improving the manufacturing of electronic devices like printed circuit boards and semiconductors.
Implementation Method 1
Methods for electroplating articles with metal coatings generally involve passing a current between two electrodes in a plating solution where one of the electrodes is the article to be plated
Implementation Method 2
copper is electroplated over selected portions of the surface of a printed circuit board, into blind vias and trenches and on the walls of through-holes
Data Source
AI summary
Copper electroplating baths include reaction products of amines and polyacrylamides. The reaction products function as levelers and enable copper electroplating baths which have high throwing power and provide copper deposits with reduced nodules.