Wafer Holding Detection via Laser Displacement Sensor
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Solution Overview
Problem
Wafers sometimes fail to be properly held in carrier holding holes during processing, leading to inefficiencies and potential breaks, as manual inspection by touch is time-consuming and prone to errors.
Innovation Solution
A method using a laser displacement sensor to detect the height position of the upper turn table before processing, determining if the wafer is normally held by comparing it to a reference position, and re-holding if necessary, eliminating the need for manual inspection and preventing wafer breaks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If manual inspection by touch is used to detect holding failures, then detection capability is provided, but processing time increases and detection accuracy decreases
Solution Approach 1:
The patent replaces the mechanical inspection method (manual touch detection) with an optical detection system. A laser displacement sensor is used to measure the position of the upper turn table, which indirectly detects whether the wafer is properly held in the carrier. This substitution eliminates the need for manual inspection while providing more accurate and automated detection.
2Reliability
If manual inspection by touch is used to detect holding failures, then detection capability is provided, but detection precision deteriorates
Solution Approach 1:
The patent replaces the mechanical inspection method (manual touch detection) with an optical detection system. A laser displacement sensor is used to measure the position of the upper turn table, which indirectly detects whether the wafer is properly held in the carrier. This substitution eliminates the need for manual inspection while providing more accurate and automated detection.
3Productivity
If automated detection using laser displacement sensor is implemented, then processing efficiency improves and detection accuracy increases, but device complexity increases
Solution Approach 1:
The patent uses the upper turn table as an intermediary element to transfer the holding state information from the wafer-carrier system to the detection system. Instead of directly detecting the wafer's holding state, the system measures the position of the upper turn table, which changes position when the wafer is not properly held. This intermediary approach simplifies the detection system while maintaining high accuracy.
4Productivity
If automated detection using laser displacement sensor is implemented, then processing efficiency improves, but device complexity increases
Solution Approach 1:
The patent uses the upper turn table as an intermediary element to transfer the holding state information from the wafer-carrier system to the detection system. Instead of directly detecting the wafer's holding state, the system measures the position of the upper turn table, which changes position when the wafer is not properly held. This intermediary approach simplifies the detection system while maintaining high accuracy.
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 allows for accurate and automatic detection of holding failures, enhancing processing efficiency and preventing wafer breaks by ensuring proper holding before processing both surfaces.
Implementation Method 1
detecting a height position of the upper turn table by a laser displacement sensor
Data Source
AI summary
The invention provides a method for processing a wafer by inserting the wafer into a holding hole of a carrier to hold the wafer, and interposing the carrier holding the wafer between an upper turn table and a lower turn table to process both surfaces of the wafer simultaneously, including: before processing the wafer, detecting a height position of the upper turn table by a laser displacement sensor while interposing the carrier holding the wafer between the upper turn table and the lower turn table; and determining that the wafer is not normally held to redo the holding of the wafer if a difference between the detected height position and a reference position exceeds a threshold. The method can automatically detect accurately a failure in holding the wafer before processing to prevent the wafer from breaking and eliminate the necessity of operator's inspection using touch to improve operation efficiency.