Catalyst Application Bath for Electroless Plating Patternability
Solution Overview
Problem
Conventional catalyst application methods for electroless plating on fine copper traces result in out-of-pattern deposition due to residual palladium catalyst, leading to short circuits, and require a post-dip step that can inhibit deposition, making it difficult to achieve both patternability and electroless plating as trace patterns and spaces become finer.
Innovation Solution
A catalyst application bath containing a palladium compound and an aminocarboxylic acid, with specific concentration ranges and pH levels, which forms a stable complex with palladium, allowing for effective washing and reducing unnecessary palladium outside patterns, thus eliminating the need for a post-dip step and ensuring both patternability and electroless plating deposition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional activator is used to apply palladium catalyst on copper traces, then catalytic deposition can be achieved, but residual catalyst remains between traces causing out-of-pattern deposition and short circuits
Solution Approach 1:
A post-dip solution containing a chelating agent (e.g., EDTA, DTPA, or NTA) is introduced as an intermediary step between catalyst application and electroless plating. This post-dip selectively removes residual palladium catalyst from non-pattern areas through chelation, preventing out-of-pattern deposition while preserving catalyst on copper traces for subsequent plating
Solution Approach 2:
The patent optimizes parameters including post-dip solution composition (chelating agent concentration at 1-50 g/L), temperature (20-80°C), and immersion time (10 seconds to 5 minutes) to achieve selective removal of residual catalyst. The pH is controlled at 2-12 to ensure effective chelation while maintaining pattern integrity
2Manufacturing precision
If a post-dip step is performed to remove residual catalyst and prevent out-of-pattern deposition, then patternability improves, but catalyst applied to copper traces is also affected causing non-deposition in plating
Solution Approach 1:
The post-dip process exploits local quality differences between patterned copper traces and non-pattern areas. The chelating agent selectively interacts with residual catalyst in non-pattern areas while having minimal effect on catalyst already deposited on copper surfaces, achieving spatially differentiated treatment that preserves both patternability and plating capability
3Productivity
If trace patterns and spaces become finer to increase device density, then device capacity increases, but conventional activator and post-dip techniques become ineffective achieving both patternability and electroless plating
Solution Approach 1:
The patent adjusts key parameters for fine-pitch applications including reducing post-dip immersion time (10 seconds to 2 minutes), optimizing chelating agent concentration (1-50 g/L), and controlling temperature (20-80°C) to enhance selectivity and prevent over-removal of catalyst in narrow spaces while maintaining effective pattern coverage
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 catalyst application bath provides excellent patternability and electroless plating deposition without a post-dip step, preventing out-of-pattern deposition and ensuring reliable performance in finer copper trace patterns and denser electronic devices.
Implementation Method 1
a catalyst application bath for electroless plating, containing at least one palladium compound and at least one aminocarboxylic acid
Data Source
AI summary
Provided are a catalyst application bath for electroless plating, a method of producing a catalytic nucleus-containing material to be electroless plated using the catalyst application bath for electroless plating, a method of producing a material with an electroless plating deposit, and a material with an electroless plating deposit, each of which may provide good patternability even without a post-dip step which can cause non-deposition in electroless plating, and thus may achieve both patternability and electroless plating deposition. Included is a catalyst application bath for electroless plating, containing a palladium compound and an aminocarboxylic acid.