Imidazoyl Urea Polymer for Void-Free Copper Plating
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Solution Overview
Problem
Current additives in acidic copper plating baths are not suitable for fulfilling the requirements of advanced printed circuit board and IC substrate manufacturing, particularly in filling blind micro vias and through silicon vias without creating dimples or voids, and for metallization of semiconducting and glass substrates.
Innovation Solution
Incorporating an imidazoyl urea polymer as a dual-functional leveller and carrier-suppressor in aqueous metal or metal alloy plating baths for electrolytic deposition of copper or copper alloys, which allows for uniform filling of recessed structures with minimal dimple formation and void-free deposition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional additives are used in acidic copper plating baths, then the plating process can be maintained, but the requirements for filling blind micro vias and through silicon vias without creating dimples or voids cannot be fulfilled
Solution Approach 1:
The patent combines leveller and carrier-suppressor functions into a single imidazoyl urea polymer additive. This merged additive simultaneously provides levelling action to prevent dimples and carrier-suppression to enable complete filling of recessed structures, resolving the contradiction between manufacturing precision and adaptability for advanced substrates
Solution Approach 2:
The invention uses a composite polymer structure containing both imidazoyl and urea moieties. The imidazoyl groups provide carrier-suppression functionality while the urea groups provide levelling functionality. This composite molecular structure enables the single additive to fulfill multiple requirements for advanced PCB and IC substrate manufacturing
2Adaptability or versatility
If multiple individual additives are used in plating baths, then various functions can be achieved, but the complexity of the additive system increases
Solution Approach 1:
The imidazoyl urea polymer is designed to perform multiple functions simultaneously: it acts as both a leveller and a carrier-suppressor. This multi-functional additive reduces the number of separate chemicals needed in the plating bath while maintaining all necessary functional capabilities, thus reducing system complexity without sacrificing versatility
3Manufacturing precision
If conventional levellers and carrier-suppressors are used separately, then their individual functions can be optimized, but complete and void-free filling of recessed structures with minimal dimple formation cannot be achieved
Solution Approach 1:
The patent merges leveller and carrier-suppressor into a single dual-functional imidazoyl urea polymer. This combination achieves complete and void-free filling of recessed structures with minimal dimple formation while simplifying the manufacturing process by reducing the number of additives and their associated handling requirements
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 imidazoyl urea polymer enables complete and void-free filling of recessed structures with acceptable dimple formation, meeting industrial requirements for copper deposition in complex substrate geometries, including blind micro vias, through silicon vias, and through glass vias, while reducing the need for additional leveller and carrier-suppressor additives.
Implementation Method 1
aqueous metal or metal alloy plating baths for electrolytic deposition of copper or copper alloys
Implementation Method 2
electrolytic deposition of copper or copper alloys
Data Source
AI summary
The present invention relates to imidazoyl urea polymers and their use in aqueous acidic plating baths for metal or metal alloy deposition such as electrolytic deposition of copper or alloys thereof 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 at least one source of metal ions and an imidazoyl urea polymer. The plating bath is particularly useful for filling recessed structures and build-up of pillar bump structures.