Sn Alloy Plating Apparatus with Segmented Electrolysis and Dialysis
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Solution Overview
Problem
Existing Sn alloy plating methods face challenges in maintaining a constant Sn ion concentration and acid concentration in the plating solution, leading to poor film appearance and non-uniformity of film thickness.
Innovation Solution
An Sn alloy plating apparatus and method that includes a plating bath with a circulation system, an Sn supply reservoir for replenishing Sn ions, and a dialysis unit for adjusting acid concentration, ensuring constant Sn ion concentration and maintaining acid levels within a preferable range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If a soluble anode (Sn anode) is used to replenish Sn ions in the plating solution, then the Sn ion concentration can be maintained, but the acid concentration cannot be controlled and may fall outside the preferable range
Solution Approach 1:
The invention divides the plating system into two separate chambers: an anode chamber containing the Sn anode for Sn ion replenishment, and a plating chamber containing the plating solution. This segmentation allows independent control of Sn ion supply and acid concentration management, resolving the contradiction between maintaining Sn ion concentration and controlling acid concentration.
Solution Approach 2:
A diaphragm is introduced as an intermediary component between the anode chamber and plating chamber. This diaphragm allows selective ion transport while preventing direct mixing, enabling Sn ions to reach the plating solution while blocking excessive acid migration, thus facilitating independent control of both Sn ion and acid concentrations.
2Ease of operation
If an insoluble anode is used, then the acid concentration can be controlled, but the Sn ion concentration cannot be maintained constant
Solution Approach 1:
The segmented chamber design with separate anode and plating chambers enables the use of an insoluble anode in the anode chamber while still achieving Sn ion replenishment through controlled electrolysis and diaphragm-mediated ion transport, thus maintaining both acid concentration control and Sn ion concentration stability.
3Quantity of substance
If Sn ions are replenished without considering acid concentration, then the Sn concentration can be kept constant, but the film appearance and thickness uniformity deteriorate
Solution Approach 1:
By segmenting the plating system into separate chambers, the invention enables independent optimization of Sn ion replenishment and acid concentration control, ensuring both parameters remain within preferable ranges for producing films with good appearance and uniform thickness.
Solution Approach 2:
The system incorporates monitoring and adjustment mechanisms that provide feedback on both Sn ion concentration and acid concentration, allowing real-time adjustments to maintain optimal plating conditions and ensure consistent film quality.
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 allows for precise control of Sn ion and acid concentrations, resulting in improved film quality with uniform thickness and appearance.
Implementation Method 1
perform electrolysis in a presence of the drawn Sn alloy plating solution to replenish the Sn alloy plating solution with Sn ions
Implementation Method 2
a dialysis unit configured to draw a part of the Sn alloy plating solution from the plating-solution circulation line, remove the acid from the Sn alloy plating solution, and then return the Sn alloy plating solution to the plating bath
Implementation Method 3
a plating-solution circulation line configured to circulate the Sn alloy plating solution in the plating bath
Data Source
AI summary
An Sn alloy plating apparatus is disclosed which can relatively easily perform control of an Sn alloy plating solution, including control of the Sn ion concentration and the acid concentration of the plating solution. The Sn alloy plating apparatus includes: a plating bath configured to hold therein an Sn alloy plating solution in which an insoluble anode a the substrate are to be disposed opposite each other; a plating-solution circulation line configured to circulate the Sn alloy plating solution in the plating bath; an Sn supply reservoir configured to draw a part of the Sn alloy plating solution from the plating-solution circulation line, perform electrolysis in a presence of the Sn alloy plating solution to replenish the Sn alloy plating solution with Sn ions and an acid that stabilizes Sn ions, and return the Sn alloy plating solution that has been replenished with the Sn ions to the plating bath; and a dialysis unit configured to draw a part of the Sn alloy plating solution from the plating-solution circulation line, remove the acid from the Sn alloy plating solution, and then return the Sn alloy plating solution to the plating bath.