Ureylene Polymer Copper Plating Bath for Void-Free TSV Filling
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Solution Overview
Problem
Aqueous acidic copper plating baths used for electro-deposition in printed circuit boards and semiconducting substrates fail to achieve complete and void-free filling of recessed structures like blind micro vias, through silicon vias, and through glass vias while maintaining minimal copper deposition on neighboring areas, due to limitations in current leveler additives.
Innovation Solution
An aqueous acidic copper plating bath composition containing a source of copper ions and a ureylene polymer with terminal amino groups, free of intentionally added zinc ions, is used to fill recessed structures without voids and with minimal dimple formation, allowing for complete and conformal copper deposition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional leveler additives are used in acidic copper plating baths, then copper deposition occurs on substrate surfaces, but complete and void-free filling of recessed structures cannot be achieved while maintaining minimal copper deposition on neighboring areas
Solution Approach 1:
The invention changes the chemical parameters of the plating bath by replacing conventional leveler additives with a specific ureylene polymer having terminal amino groups. This polymer modifies the deposition parameters to achieve superior filling quality with minimal overplating, resolving the contradiction between filling quality and deposition selectivity
Solution Approach 2:
The invention uses a composite additive system comprising a ureylene polymer with terminal amino groups combined with carrier additives and brighteners. This composite approach enables simultaneous achievement of complete recessed structure filling and controlled copper deposition on planar areas, addressing both filling quality and deposition selectivity requirements
2Manufacturing precision
If copper deposition is increased to ensure complete filling of recessed structures, then void-free filling is achieved, but excessive copper deposits on neighboring planar areas
Solution Approach 1:
The ureylene polymer additive provides local quality control by differentiating the deposition behavior in recessed areas versus planar areas. It enables complete filling of recessed structures while maintaining minimal copper deposition on neighboring planar areas, thus resolving the contradiction between filling completeness and copper consumption control
3Manufacturing precision
If conventional plating baths are used for advanced applications, then standard copper deposition occurs, but the required surface planarity and minimal dimple formation cannot be achieved
Solution Approach 1:
The invention modifies the plating bath composition parameters by introducing a ureylene polymer with specific terminal amino groups. This change produces superior surface planarity and minimal dimple formation in filled recessed structures, meeting the stringent requirements of advanced applications without increasing process complexity
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 enables void-free and dimple-free copper filling of recessed structures, meeting the requirements for advanced printed circuit boards, IC substrates, and semiconducting substrates, including TSV filling and through glass vias, with improved surface planarity and reduced overplating on neighboring areas.
Implementation Method 1
aqueous acidic plating bath composition for electrolytic deposition of copper
Implementation Method 2
electrolytic deposition of copper or copper alloys
Data Source
AI summary
The present invention relates to aqueous acidic plating baths for copper and copper alloy deposition 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 comprising amino residues on both termini and which is free of organically bound halogen. The plating bath is particularly useful for filling recessed structures with copper and build-up of pillar bump structures.