Two-Bath Electroplating Chamber for Catholyte Contaminant Removal
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Solution Overview
Problem
Conventional methods for reducing metal ion contaminants in electroplating systems, such as copper in tin-containing electrolytes, are costly and require extensive downtime due to frequent electrolyte replacement, leading to defects and inefficiencies in semiconductor processing.
Innovation Solution
A two-bath electroplating system with a contaminant retrieval system using a vessel or packed bed of tin-containing particles, operated at specific voltage potentials, to electrochemically remove contaminants like copper from the catholyte, maintaining low contaminant levels without replacing the electrolyte.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If electrolyte replacement is performed to remove metal ion contaminants, then contaminant levels are reduced, but system downtime increases and operational costs increase
Solution Approach 1:
The contaminant retrieval system performs preliminary removal of metal ion contaminants from the electrolyte before they accumulate to problematic levels. By continuously or periodically removing contaminants through electrochemical deposition on sacrificial anodes, the system maintains electrolyte quality without requiring complete replacement, thus avoiding extended downtime while preserving reliability.
Solution Approach 2:
The electrochemical cell is integrated into the electrolyte circulation system to provide self-service contaminant removal. The sacrificial anodes automatically deposit contaminants from the electrolyte through electrochemical reactions, enabling the system to maintain its own electrolyte quality without external intervention or shutdown, thereby reducing downtime while ensuring continuous reliability.
2Reliability
If electrolyte replacement is performed to remove metal ion contaminants, then contaminant levels are reduced, but operational costs increase
Solution Approach 1:
The system recovers valuable metal ions from the electrolyte by depositing them onto sacrificial anodes through electrochemical reactions. Instead of discarding the entire electrolyte when contaminants accumulate, the retrieval system selectively removes and concentrates contaminants on the anodes, which can then be replaced while the bulk electrolyte is retained and reused, significantly reducing material costs while maintaining electrolyte quality.
Solution Approach 2:
The electrochemical cell provides self-service contaminant removal by using sacrificial anodes that automatically deposit metal ion contaminants from the electrolyte through electrochemical reactions. This continuous or periodic removal process maintains electrolyte quality without requiring complete replacement, thereby reducing operational costs while preserving reliability.
3Reliability
If conventional contaminant removal methods are used, then contaminant levels are reduced, but process efficiency decreases
Solution Approach 1:
The contaminant retrieval system operates continuously or periodically alongside the main electroplating process, removing contaminants as they accumulate in the electrolyte. This continuous action maintains contaminant levels below threshold values throughout production, ensuring consistent product quality without interrupting the plating process, thereby preserving high productivity while achieving reliable contaminant control.
Solution Approach 2:
The system performs preliminary contaminant removal before contaminant levels reach problematic thresholds that would affect product quality. By proactively maintaining electrolyte quality through continuous or periodic retrieval operations, the system prevents defects and rework, ensuring consistent productivity without compromising contaminant control.
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
Reduces contaminant levels effectively, minimizing costs and downtime, while maintaining electrolyte quality and process efficiency by continuously removing contaminants like copper below 1 ppm per 5,000 wafers processed.
Implementation Method 1
passing the catholyte across a tin-containing material... reducing the copper contaminants from the catholyte... an anode and cathode driven at a voltage below a tin plating potential and above a copper plating potential
Implementation Method 2
The anode and cathode may be driven at a voltage below a tin plating potential and above a copper plating potential... The tin-containing material may be an anode of an anode-cathode pair of electrically coupled electrodes
Data Source
AI summary
Electroplating systems according to the present technology may include a two-bath electroplating chamber including a separator configured to provide fluid separation between a first bath configured to maintain a catholyte during operation and a second bath configured to maintain an anolyte during operation. The system may include a catholyte tank fluidly coupled with the first bath of the two-bath electroplating chamber. The system may also include a contaminant retrieval system configured to remove contaminant ions from the catholyte.