CMP Wafer Rotation Current Monitoring for Bubble Rupture Detection
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Solution Overview
Problem
During the CMP process, bubbles formed at the bonding surface between wafers can rupture, leading to wafer scratches, and traditional manual observation of bubble defects is time-consuming and labor-intensive.
Innovation Solution
Monitoring the current required to drive the rotation of the bonded wafer during chemical mechanical polishing, which indicates the presence or absence of bubble rupture at the bonding surface, allowing for timely detection without interrupting the polishing process and triggering an alarm for immediate action.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If manual observation is used to detect bubble defects, then detection capability is achieved, but time consumption and labor intensity increase
Solution Approach 1:
The patent replaces the manual mechanical observation system with an automated electrical measurement system. By monitoring current changes during CMP processing, the system automatically detects bubble rupture events, eliminating the need for manual visual inspection and significantly reducing time consumption and labor intensity while maintaining detection capability.
Solution Approach 2:
The system enables self-service detection by using the CMP process parameters (current consumption) to automatically indicate bubble rupture events. The process itself generates the detection signal through current monitoring, eliminating the need for separate manual inspection operations and allowing continuous automated monitoring throughout the polishing process.
2Productivity
If bubble rupture is not monitored, then production efficiency is maintained, but wafer scratches occur due to fallen wafer slags
Solution Approach 1:
The system implements real-time feedback monitoring by continuously measuring current consumption during CMP and comparing it against expected values. When bubble rupture is detected through current changes, the system can immediately alert operators or adjust parameters, providing feedback that prevents wafer scratches while maintaining production efficiency through timely intervention.
Solution Approach 2:
The system performs preliminary detection of bubble rupture events during the CMP process itself, before fallen slags can cause wafer scratches. By monitoring current changes that indicate bubble rupture, the system enables early warning and preventive action, allowing operators to address the issue before it causes harmful effects on the wafers.
3Measurement precision
If current monitoring is implemented during CMP, then bubble rupture detection is achieved, but system complexity increases
Solution Approach 1:
The patent uses current consumption as an intermediary parameter to detect bubble rupture events. Instead of directly observing bubbles or their rupture, the system monitors the electrical current required for CMP rotation, which changes as bubbles affect the polishing interface. This intermediary measurement simplifies the detection system compared to direct optical or mechanical bubble monitoring methods.
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 method enables timely detection of bubble rupture, reducing the likelihood of wafer scratches, improving production efficiency, and minimizing economic losses by automating the monitoring process.
Implementation Method 1
the second surface of the first wafer and the polishing pad being contacted, so as to generate a friction force and relative motion of the two
Data Source
AI summary
The present application provides a method for monitoring bubble breakup during CMP, wherein a bonded wafer is formed by bonding of respective first surfaces of first and second wafers, and the magnitude of the current required to drive rotation of the bonded wafer is monitored from the start of the polishing; according to the change of the monitored current driving the rotation of the first wafer, it is determined whether there is bubble rupture at a bonding surface; if the current is increased instantaneously before the bonding surface is exposed by the polishing, bubbles generated at the bonding surface rupture; and if the magnitude of the current is constant before the end of the polishing, no bubble is generated at the bonding surface or generated bubbles do not rupture.