Ureylene Polymer Copper Plating Bath for Void-Free Via Filling
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Solution Overview
Problem
Existing copper plating baths fail to achieve complete and void-free filling of recessed structures like trenches, blind micro vias, through silicon vias, and through glass vias, while maintaining a planar surface and controlling overplating on neighboring areas, which is crucial for advanced printed circuit boards, IC substrates, and semiconducting and glass substrates.
Innovation Solution
An aqueous acidic copper plating bath containing ureylene polymers, selected from specific formulas, is used to deposit copper, ensuring void-free filling of recessed structures and controlled overplating, with additives like accelerator-brighteners and carrier-suppressors to enhance deposition uniformity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional copper plating baths are used, then copper deposition occurs, but complete and void-free filling of recessed structures cannot be achieved
Solution Approach 1:
The patent employs leveler additives that selectively adsorb onto planar substrate areas, creating locally different deposition conditions. This causes copper to deposit preferentially in recessed structures (trenches, vias, blind micro vias) while suppressing deposition on flat surfaces, achieving complete filling without excessive overplating. The local quality change in additive distribution resolves the contradiction between filling quality and void-free deposition.
Solution Approach 2:
The patent utilizes accelerator-brightener and carrier-suppressor additives that modify electrochemical parameters (current density, deposition rate) locally within the plating bath. These parameter changes enable controlled copper deposition that fills recessed structures completely while maintaining planar surfaces, achieving both high filling quality and reliability of void-free deposition.
2Manufacturing precision
If copper deposition is increased to fill recessed structures, then filling completeness improves, but overplating on neighboring planar areas increases
Solution Approach 1:
The leveler additive creates local quality differences by adsorbing on planar areas, reducing copper deposition there while allowing enhanced deposition in recessed structures. This selective action achieves complete filling without excessive copper buildup on neighboring planar surfaces, resolving the contradiction between filling completeness and controlled copper quantity.
Solution Approach 2:
The leveler additive acts as an intermediary substance that mediates between the copper ions in solution and the substrate surface. It selectively inhibits deposition on planar areas while permitting it in recessed structures, enabling complete filling with controlled copper quantity on planar regions.
3Manufacturing precision
If conventional leveler additives are used, then some surface control is achieved, but current and future requirements for BMV filling and TSV filling are not met
Solution Approach 1:
The patent employs a composite additive system combining leveler, accelerator-brightener, and carrier-suppressor components with specific chemical structures (containing nitrogen, sulfur, and phosphorus atoms). This composite formulation provides superior surface control and adaptability for advanced applications like blind micro via filling, through silicon via filling, and through glass via filling, meeting both surface planarity and application-specific requirements.
Solution Approach 2:
The patent uses specially designed additives with controlled molecular structures (specific ring structures with heteroatoms) that modify electrochemical parameters to achieve precise surface control. These parameter changes enable the plating bath to meet stringent requirements for advanced applications including complete BMV filling with minimal dimple formation and void-free TSV filling, significantly improving adaptability while maintaining surface planarity.
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 ureylene polymer-based bath achieves uniform copper deposition with minimal dimples and voids, effectively filling complex structures and building up pillar bumps, meeting the stringent requirements of modern circuitry layouts.
Implementation Method 1
aqueous acidic copper electroplating bath for electrolytic deposition of copper or copper alloys
Implementation Method 2
electrolytic deposition of copper
Data Source
AI summary
The invention relates to aqueous acidic plating baths for electrodeposition of copper and copper alloys in the manufacture of printed circuit boards, IC substrates, semiconducting and glass devices for electronic applications. The plating bath according to the present invention comprises copper ions, at least one acid and an ureylene polymer. The plating bath is particularly useful for filling recessed structures with copper and build-up of pillar bump structures.