Gold Sulfite Plating Solution Desalination by Supersaturation
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Solution Overview
Problem
Existing electrochemical deposition processes for semiconductor manufacturing face challenges in efficiently removing sulfate salts from gold sulfite plating solutions, leading to inefficiencies and potential gold loss.
Innovation Solution
A method involving supersaturation, nucleation, and un-saturation processes to form and precipitate sulfate salts from gold sulfite plating solutions, using a desalinator system with a supersaturation system, in-line heater, nucleation system, and valve controls to reclaim gold and reduce sulfate content.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional electrochemical deposition processes are used, then gold plating is achieved, but sulfate salts accumulate in the plating solution leading to inefficiency and potential gold loss
Solution Approach 1:
The patent changes the concentration parameters of the plating solution by implementing a supersaturation process followed by controlled precipitation. The solution is supersaturated with sulfate salts, then treated with a nucleator to precipitate the salts, effectively removing them from the solution while maintaining gold concentration and preventing gold loss.
Solution Approach 2:
The patent extracts sulfate salts from the plating solution through a multi-step process: supersaturation to increase sulfate concentration, nucleation to form solid sulfate salt precipitates, and filtration to remove the precipitates. This extraction process removes harmful sulfate salts while preserving the gold content in the solution.
2Productivity
If sulfate salts are not removed from plating solution, then process simplicity is maintained, but inefficiency and gold loss occur
Solution Approach 1:
The patent segments the sulfate removal process into distinct operational stages: supersaturation phase, nucleation phase, and filtration phase. Each stage performs a specific function - supersaturation increases sulfate concentration, nucleation forms removable precipitates, and filtration removes the solids. This segmentation makes the complex desalination process manageable and controllable.
Solution Approach 2:
The patent introduces a nucleator as an intermediary substance to facilitate sulfate salt precipitation. The nucleator provides nucleation sites that enable sulfate ions to form solid precipitates more efficiently. This intermediary substance mediates between the supersaturated solution and the final precipitated state, making the removal process more effective.
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
Effectively removes sulfate salts, maintaining gold concentration and solution quality, thereby enhancing the efficiency and reducing gold loss in the plating process.
Implementation Method 1
supersaturating a sulfate-rich gold sulfite plating solution to form a supersaturated sulfate-rich gold sulfite plating solution
Implementation Method 2
exposing the supersaturated sulfate-rich gold sulfite plating solution to a nucleator to form sulfate salts
Implementation Method 3
in-line heater
Data Source
AI summary
Sulfate salts are removed from a gold sulfite plating solution via supersaturating a sulfate-rich gold sulfite plating solution to form a sulfate-poor saturated gold sulfite plating solution, and un-saturating the sulfate-poor saturated gold sulfite plating solution to form an unsaturated sulfate-poor gold sulfite plating solution. Gold from the unsaturated sulfate-poor gold sulfite plating solution is electrodeposited onto a workpiece.