Acid Rinse for Electroplating Cross-Contamination
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Solution Overview
Problem
Cross-contamination of copper plating baths in electroplating systems for semiconductor wafer processing is a significant issue, leading to inefficiencies and maintenance challenges due to frequent cleaning needs.
Innovation Solution
A method involving the removal of wafers from electroplating solutions and rinsing them with an acid, such as methane sulfonic acid (MSA) or carbonic acid, to form a rinsate that removes residual electroplating solution and prevents cross-contamination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiple electroplating operations with multiple electroplating solutions are performed, then productivity is improved, but cross-contamination of copper plating baths occurs leading to reduced manufacturing precision
Solution Approach 1:
The patent introduces an intermediary substance (acid rinse solution) between electroplating operations to prevent cross-contamination. The acid rinse acts as a mediator that cleans residual electroplating solution from the wafer and contact ring, allowing multiple plating operations to proceed without contamination while maintaining high productivity
Solution Approach 2:
The patent applies preliminary cleaning action by rinsing the wafer and contact ring with acid before subsequent electroplating operations. This preliminary removal of residual chemicals prevents cross-contamination in advance, enabling multiple plating baths to be used without compromising manufacturing precision
2Manufacturing precision
If frequent cleaning and de-plating of seals and electrical contacts is performed, then manufacturing precision is maintained, but productivity decreases due to idle time
Solution Approach 1:
The patent implements continuous cleaning action by rinsing the contact ring and wafer with acid during the electroplating process itself, rather than stopping for separate cleaning operations. This continuous action maintains cleanliness of contacts while eliminating idle time, preserving both manufacturing precision and productivity
Solution Approach 2:
The electroplating processor performs self-cleaning by using acid rinse to automatically clean the contact ring and wafer during normal operation. This self-service cleaning eliminates the need for external maintenance interventions, maintaining contact cleanliness while keeping the processor productive
3Manufacturing precision
If additional hardware such as seals is added to prevent cross-contamination, then manufacturing precision is improved, but device complexity increases providing additional contamination vectors
Solution Approach 1:
The patent extracts the cleaning function from separate hardware components (seals, contact rings) and integrates it into the chemical process itself. By using acid rinse to chemically clean surfaces, the patent removes the need for complex mechanical sealing systems, reducing device complexity while maintaining manufacturing precision
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
This approach effectively reduces cross-contamination in electroplating systems and wafers, enhancing the throughput and maintenance efficiency of the electroplating processor by minimizing the need for frequent cleaning.
Implementation Method 1
rinsing the wafer with an acid, where the acid contacts a residual electroplating solution on the wafer and forms a rinsate
Data Source
AI summary
A method of reducing cross-contamination on a wafer, the method including removing the wafer from an electroplating solution, rinsing the wafer with an acid, wherein the acid contacts residual electroplating solution on the wafer and forms a rinsate, and removing the rinsate from the wafer. Further, a method of removing cross-contamination on a wafer, the method including rinsing the wafer with a methane sulfonic acid (MSA) mixture, where the MSA mixture contacts residual electroplating solution on the wafer and forms a rinsate and removing the rinsate from the wafer.