Ultrasonic Wafer Peeling with Timing Detection and Suction Transfer
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Solution Overview
Problem
The existing methods for peeling wafers from ingots using a peeling layer formed by a laser beam or ultrasonic waves face challenges in productivity and wafer damage due to difficulty in detecting the precise peeling timing, leading to potential wafer loss during delivery.
Innovation Solution
A peeling apparatus that includes a holding table, water supply unit, ultrasonic unit, peeling confirmation unit, and wafer delivery unit, where the peeling confirmation unit detects the peeling timing to ensure secure delivery of the wafer by retracting the other units and using a suction pad to hold and deliver the wafer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of substance
If a laser beam is applied to form a peeling layer in the ingot, then the economical use of the ingot is improved, but the productivity deteriorates due to difficulty in peeling off the wafer
Solution Approach 1:
The patent combines two previously separate processes into one integrated system: laser processing for peeling layer formation and ultrasonic processing for wafer separation. The laser unit forms the peeling layer while the ultrasonic unit simultaneously or subsequently applies vibrations to facilitate easy peeling, merging the advantages of both methods into a single automated workflow that improves both material utilization and productivity.
Solution Approach 2:
The system maintains continuous operation by seamlessly transitioning from laser peeling layer formation to ultrasonic wafer separation without manual intervention. The automated control unit coordinates both processes to occur in continuous sequence, eliminating idle time and maintaining productive action throughout the wafer separation operation.
2Productivity
If ultrasonic waves are applied to peel off the wafer efficiently, then the productivity is improved, but the measurement precision deteriorates due to difficulty in identifying peeling timing
Solution Approach 1:
The detection unit continuously monitors the peeling process by detecting changes in ultrasonic wave characteristics, vibration patterns, or acoustic emissions that occur when the wafer separates from the ingot. This feedback mechanism provides real-time information about peeling status, enabling precise timing detection and automated control of the peeling operation.
Solution Approach 2:
The patent replaces manual visual inspection or mechanical timing methods with automated detection using sensors that monitor physical parameters such as vibration, acoustic signals, or force changes. This substitution of mechanical detection with sensor-based measurement enables precise, objective timing detection of the peeling event.
3Reliability
If the wafer is delivered while being held under suction after peeling, then the wafer can be securely transported, but the wafer may fall off due to water flow if peeling timing is not accurately detected
Solution Approach 1:
The suction pad is positioned and ready to immediately grasp the wafer as soon as peeling is detected, eliminating any delay between wafer separation and secure holding. The system prepares the delivery mechanism in advance so that the transition from peeling to secure holding is seamless, preventing the wafer from being exposed to harmful water flow or falling.
Solution Approach 2:
The suction pad creates a secure holding force on the wafer immediately upon detection of peeling completion, cushioning against potential harmful effects such as water flow or gravitational falling. This prior establishment of secure holding prevents damage before it can occur.
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
The apparatus effectively prevents wafer damage and loss by accurately detecting the peeling timing and securely delivering the wafer from the ingot, enhancing productivity.
Implementation Method 1
a water supply unit that forms a layer of water on an upper surface of the ingot
Implementation Method 2
an ultrasonic unit that applies an ultrasonic wave to the upper surface of the ingot through the layer of water
Implementation Method 3
a wafer delivery unit that lowers a suction pad having a suction surface facing the upper surface of the ingot, to hold the wafer to be manufactured on the suction surface under suction
Data Source
AI summary
A peeling apparatus includes a holding table that holds an ingot, a water supply unit that forms a layer of water on an upper surface of the ingot, an ultrasonic unit that applies an ultrasonic wave to the upper surface of the ingot through the layer of water, a peeling confirmation unit that confirms peeling-off of a wafer to be manufactured, a wafer delivery unit that lowers a suction pad having a suction surface facing the upper surface of the ingot, to hold the wafer to be manufactured on the suction surface under suction, and delivers the wafer from the ingot, and a controller. After the peeling-off of the wafer is confirmed by the peeling confirmation unit, the controller positions the water supply unit, the ultrasonic unit, and the peeling confirmation unit at retracted positions and operates the wafer delivery unit to deliver the wafer from the ingot.