Wafer Plating Current Monitoring for Film Uniformity Control
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Solution Overview
Problem
The challenge of achieving uniformity in the plating film on wafers during electroplating processes is exacerbated by metal residue at the interface between the electroplating device and the wafer surface, leading to inconsistent current distribution and thinner films at the edge, which can result in wafer scrapping.
Innovation Solution
A method and system that monitor current differences across the wafer surface, perform a check-up operation when deviations exceed a preset threshold, and clean the plating device to remove unwanted attachments, using a combination of ammonia water and a mixed solution to maintain uniformity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the electroplating device is used continuously without cleaning, then productivity is improved, but metal residue accumulates on the plating device causing non-uniform current distribution and degraded plating quality
Solution Approach 1:
The system continuously monitors current distribution across the wafer surface during plating operations. When non-uniformity exceeds a threshold, the system automatically triggers a check-up operation to detect metal residue on the plating device, and subsequently initiates cleaning operations. This closed-loop feedback mechanism enables the system to maintain plating quality while maximizing productivity by cleaning only when necessary.
Solution Approach 2:
The plating device incorporates self-diagnostic and self-cleaning capabilities. The detection assembly automatically identifies metal residue accumulation on the plating device, and the cleaning assembly performs maintenance operations without requiring external intervention. This self-service approach minimizes downtime while ensuring consistent plating quality.
2Manufacturing precision
If the plating device is cleaned frequently to maintain uniformity, then manufacturing precision is improved, but productivity decreases due to increased downtime
Solution Approach 1:
Instead of scheduled frequent cleaning, the system uses real-time current monitoring to trigger cleaning operations only when non-uniformity indicates metal residue accumulation. This demand-driven approach maintains plating quality while minimizing unnecessary cleaning downtime, thereby optimizing productivity.
Solution Approach 2:
The system automatically detects when cleaning is needed through current distribution analysis and performs cleaning operations autonomously. This eliminates the need for manual inspection and scheduling, reducing downtime while maintaining consistent plating quality.
3Device complexity
If current distribution is not monitored, then device complexity is reduced, but manufacturing precision deteriorates due to undetected non-uniform plating
Solution Approach 1:
The system incorporates a monitoring assembly that measures current distribution across the wafer surface during plating. This feedback mechanism provides real-time information about plating uniformity, enabling automatic detection of metal residue accumulation and triggering appropriate cleaning operations to maintain quality.
Solution Approach 2:
Instead of complex mechanical inspection systems to detect metal residue, the patent uses electrical measurement of current distribution as a proxy indicator. This substitution simplifies the monitoring system while providing effective detection capability for maintaining plating uniformity.
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 ensures timely detection and correction of non-uniform plating, reducing the need for scrapping by maintaining consistent current distribution and improving the overall quality and yield of the plating process.
Implementation Method 1
currents at different areas of a surface of the wafer are monitored in a plating process
Implementation Method 2
a cleaning operation is performed on the plating device
Implementation Method 3
The current causes the metal to be ionized and conducted to the surface of the wafer through an electroplating device, thereby forming a thin and solid metal film on the surface of the wafer
Implementation Method 4
The current causes the metal to be ionized and conducted to the surface of the wafer
Data Source
AI summary
A method and system for improving uniformity of plating film on the wafer are provided. The method includes: providing a plating device; providing a wafer, the plating device being configured to coat the wafer; monitoring currents at different areas of a surface of the wafer in a plating process; when a difference between the currents at the different areas of the surface of the wafer is greater than a preset difference, inspecting the plating device; and when an attachment is present on the plating device, cleaning the plating device.