Polyaminoamide Copper Plating Bath for Void-Free Feature Filling
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Solution Overview
Problem
There is a need for an acidic copper electroplating bath that produces copper deposits with good morphology, low roughness, and improved uniformity in height, particularly for filling recessed features on the micrometer scale without forming defects like voids.
Innovation Solution
The use of cationic aminoamide polymers as leveling agents in the copper electroplating composition, which includes copper ions and an acid, provides extraordinary leveling properties, ensuring uniform and planar copper deposits in recessed features.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional leveling agents are used in copper electroplating, then copper deposits can be formed, but the deposits exhibit high roughness and poor uniformity in height
Solution Approach 1:
The patent changes the chemical parameters of the leveling agent by using polyaminoamide polymers with specific molecular weights (1,000-100,000 g/mol) and nitrogen contents (10-40%), which fundamentally alters the deposition characteristics to achieve smooth, uniform copper deposits with reduced roughness and improved height uniformity
Solution Approach 2:
The patent employs composite additive systems combining polyaminoamide leveling agents with other electroplating additives (accelerators, suppressors, brighteners) to achieve synergistic effects that simultaneously control deposition rate, surface morphology, and uniformity across varying current densities
2Manufacturing precision
If copper electroplating is performed to fill recessed features, then copper deposits are formed, but voids and defects are generated in the deposited layer
Solution Approach 1:
The patent applies local quality control by using polyaminoamide leveling agents that selectively adsorb at different locations (recessed features vs. planar surfaces) with different adsorption densities, enabling bottom-up filling of recesses while maintaining uniform deposition across the entire substrate and preventing void formation
Solution Approach 2:
The patent implements preliminary action by pre-adsorbing polyaminoamide polymers onto the substrate surface before copper deposition begins, creating a controlled interface that guides subsequent copper ion reduction and ensures defect-free filling of recessed features from the outset
3Manufacturing precision
If polyaminoamide leveling agents are used to achieve uniform deposition, then coplanarity and surface quality improve, but the plating process complexity increases
Solution Approach 1:
The patent achieves universality by designing polyaminoamide polymers that simultaneously perform multiple functions: leveling, smoothing, void prevention, and uniformity control across different feature geometries (bumps, recesses, vias), eliminating the need for multiple specialized additives and simplifying the overall process
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 composition achieves improved coplanarity of plated copper bumps, low roughness, and void-free filling of recessed features, enhancing the reliability and efficiency of the electroplating process.
Implementation Method 1
copper is deposited by copper electroplating on the exposed surface of the seed layer in the openings to thereby form copper bumps
Data Source
AI summary
Described herein is a copper electroplating composition including copper ions, an acid, and at least one polyaminoamide including a group of formula L1[B-A-B′—Z]n[Y—Z]m (L1)that is obtainable by reacting a diamine compound including two primary or secondary amino groups with an amino acid in a molar ratio of approx. 1:2 to form an aminoamide compound that is afterwards reacted with a coupling agent and optionally with a diamine co-monomer.