Polycarboxylate Ether Suppressor for Electroplating Stability
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Solution Overview
Problem
Existing electroplating processes face issues with electrochemical stability, degradation of additives over time, and the need for uniform, smooth metal layer deposition with minimal defects, especially in features with small apertures and high aspect ratios.
Innovation Solution
The use of a polycarboxylate ether suppressor, obtained by polymerizing specific ethylenically unsaturated monomers, in a metal plating bath to control the electroplating process, ensuring high electrochemical stability and uniform metal layer deposition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional suppressors are used in electroplating baths, then deposition quality can be maintained, but electrochemical stability deteriorates due to additive degradation over time
Solution Approach 1:
The patent changes the chemical structure parameters of the suppressor by introducing polyalkylene oxide radicals (particularly polyethylene oxide and polypropylene oxide groups) into the polymer backbone. This structural modification enables the suppressor to resist electrochemical degradation while maintaining its deposit-modifying properties, thereby improving electrochemical stability without sacrificing deposition quality
Solution Approach 2:
The suppressor is designed as a copolymer combining hydrophobic backbone segments with hydrophilic polyalkylene oxide side chains. This composite structure allows the molecule to interact with both the metal surface and the aqueous plating bath environment, providing stable suppressor behavior and consistent deposition quality over extended periods
2Productivity
If high current density is applied to achieve fast plating, then productivity increases, but deposition uniformity deteriorates leading to defects and rough surfaces
Solution Approach 1:
The suppressor exhibits dynamic adsorption behavior on the cathode surface, adjusting its coverage and conformation in response to varying current densities. At higher current densities, the suppressor dynamically adapts to maintain uniform deposit formation, preventing defects and roughness that would otherwise occur at high plating speeds
3Productivity
If conventional suppressors are used, then plating process can proceed, but electrochemical degradation occurs reducing process stability
Solution Approach 1:
The patent designs a suppressor with exceptional durability that does not need to be frequently replaced like conventional short-lived additives. The polyalkylene oxide structure resists electrochemical degradation, allowing the suppressor to maintain its function throughout the entire service life of the plating bath, thereby ensuring continuous process operation with stable composition
4Manufacturing precision
If suppression is strong to prevent defects, then deposition quality improves, but filling capability in small features deteriorates
Solution Approach 1:
The suppressor exhibits local quality variations in its suppressive effect based on the local geometry of the substrate. In narrow trenches and small features, the suppressor's adsorption is limited by mass transport, allowing enhanced metal ion penetration and complete filling. On open surfaces, the suppressor maintains its deposit-modifying function for high-quality deposition, thus achieving both filling and surface quality simultaneously
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 polycarboxylate ether suppressor enhances electrochemical stability, improves deposition quality, and achieves smooth, defect-free metal layers with uniform thickness, particularly in small-scale features.
Implementation Method 1
The suppressor is a polycarboxylate ether obtainable by polymerizing a mixture of monomers comprising (I) at least one ethylenically unsaturated monomer (I) which comprises at least one radical from the series carboxylic acid, carboxylic salt, carboxylic ester, carboxylic amide, carboxylic anhydride, and carboxylic imide; and (II) at least one ethylenically unsaturated monomer (II) having a polyalkylene oxide radical
Implementation Method 2
a process for depositing a metal layer on a substrate by contacting the substrate with a metal plating bath comprising a metal ion source and a suppressor, and applying a current density to the substrate
Data Source
AI summary
The present invention relates to a process for depositing a metal layer on a substrate by contacting the substrate with a metal plating bath comprising a metal ion source and a suppressor, and applying a current density to the substrate, where the suppressor is a polycarboxylate ether as described below. The invention further relates to a metal plating bath comprising a metal ion source and the suppressor which is a polycarboxylate ether; and to a use of the polycarboxylate ether in a metal plating bath for depositing a metal layer on a substrate.