Copper Plating Bath Leveling Agent for PCB Via Filling
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Solution Overview
Problem
Current copper electroplating baths struggle to achieve uniform copper deposits on substrates with irregular topography, particularly in PCBs containing both through-holes and blind vias, as existing leveling agents compromise throwing power and result in uneven thickness and defects.
Innovation Solution
A copper electroplating bath comprising a source of copper ions, an electrolyte, and a leveling agent that is a reaction product of cyclodiaza-compounds with epoxide-containing compounds, which provides a substantially level copper layer with improved throwing power and reduced defects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional leveling agents are used in copper electroplating baths, then surface leveling of copper deposits is improved, but throwing power deteriorates
Solution Approach 1:
The patent changes the chemical parameters of the leveling agent by using reaction products of cyclodiaza-compounds with epoxide-containing compounds instead of conventional leveling agents. This chemical parameter change enables simultaneous achievement of surface leveling and maintained throwing power, resolving the contradiction between these two properties.
Solution Approach 2:
The invention creates a composite chemical system by combining cyclodiaza-compounds with epoxide-containing compounds to form reaction products that function as leveling agents. This composite approach provides both leveling capability and throwing power retention, overcoming the limitations of single-component conventional agents.
2Manufacturing precision
If conventional leveling agents are used to achieve uniform copper deposits, then deposit uniformity is improved, but filling of through-holes and blind vias deteriorates
Solution Approach 1:
The patent modifies the chemical composition parameters by employing reaction products of cyclodiaza-compounds with epoxide-containing compounds as leveling agents. This parameter modification enables the plating bath to simultaneously achieve uniform copper deposits and effective filling of through-holes and blind vias, resolving the contradiction between deposit uniformity and via filling.
3Productivity
If electroplating is performed on substrates with irregular topography, then production efficiency is maintained, but deposit thickness uniformity deteriorates
Solution Approach 1:
The invention changes the chemical parameters of the plating bath by incorporating reaction products of cyclodiaza-compounds with epoxide-containing compounds. These modified parameters enable the bath to handle substrates with irregular topography while maintaining both production efficiency and uniform deposit thickness, resolving the contradiction between productivity and manufacturing precision.
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 deposits across substrates with varied features, significantly reducing defects like nodules and ensuring effective filling of through-holes and blind vias without compromising throwing power, resulting in high-quality copper layers with minimal voids and improved thermal reliability.
Implementation Method 1
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
Implementation Method 3
leveling agents are often used in copper plating baths to provide substantially uniform, or level, copper layers
Data Source
AI summary
Copper plating baths containing a leveling agent that is a reaction product of one or more of certain cyclodiaza-compounds with one or more epoxide-containing compounds that deposit copper on the surface of a conductive layer are provided. Such plating baths deposit a copper layer that is substantially planar on a substrate surface across a range of electrolyte concentrations. Methods of depositing copper layers using such copper plating baths are also disclosed.