Laser Beam Sensor Calibration for Wafer Debonding Precision
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Solution Overview
Problem
The precise alignment of a scan laser beam on a wafer during semiconductor manufacturing is challenging due to variations in spot size and position, as well as scan magnification, which can lead to damage to sensitive circuits.
Innovation Solution
A method and system that utilize multiple optical slits and a processor to determine the spot size and position of the scan laser beam by converting the laser beam into electrical pulses, allowing for calibration of the beam's spot size and position, and adjustment of the scan magnification.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a scan laser beam is used for wafer debonding, then debonding efficiency is improved, but alignment precision deteriorates due to spot size and position variations
Solution Approach 1:
The patent applies preliminary action by performing laser beam characterization (measuring spot size, position, and scan magnification) before the actual wafer debonding process. The system pre-determines these parameters using optical slits and photodetectors, then uses this information to calculate correction values that compensate for beam variations during debonding, ensuring both efficiency and precision
Solution Approach 2:
The patent implements feedback by continuously monitoring laser beam parameters through optical slits and photodetectors during the scanning process. The system measures actual spot size, position, and scan magnification, compares them to expected values, and applies correction values to the scan pattern to maintain alignment precision throughout the debonding operation
2Productivity
If laser beam parameters are not calibrated, then processing speed is maintained, but manufacturing precision deteriorates due to spot size and position variations
Solution Approach 1:
The system performs preliminary calibration by measuring laser beam parameters (spot size, position, scan magnification) before processing. This pre-characterization allows the system to establish correction values that will be applied during actual processing, ensuring precision without sacrificing processing speed during the main debonding operation
Solution Approach 2:
The patent applies parameter changes by dynamically adjusting scan pattern parameters based on measured laser beam characteristics. The system modifies scan position, spot size compensation, and scan magnification factors to match actual beam conditions, maintaining both processing speed and precision through real-time parameter adaptation
3Measurement precision
If multiple optical slits and sensors are added for laser beam sensing, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent applies segmentation by dividing the sensing function into multiple independent optical slits (first, second, and third slits) positioned at different locations. Each slit independently measures specific beam characteristics, and the system processes these separate measurements to determine spot size, position, and scan magnification, achieving high precision through distributed sensing
Solution Approach 2:
The patent implements universality by designing a single laser beam sensing system that performs multiple measurement functions simultaneously. The same optical slits and photodetector assembly measure spot size, beam position, and scan magnification all in one integrated system, reducing overall device complexity compared to having separate systems for each measurement
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
Enables accurate and efficient alignment of the laser beam, ensuring precise debonding of wafers without damaging sensitive circuits by determining the spot size and position, and correcting scan magnification errors.
Implementation Method 1
converting the scan laser beam picked up at the first position to a first electrical pulse; converting the scan laser beam picked up at the second position to a second electrical pulse; converting the scan laser beam picked up at the third position to a third electrical pulse
Data Source
AI summary
A method for aligning a scan laser beam on a wafer include scanning a scan laser beam across a laser beam sensor along a scan line, picking up a scan laser beam, at a first position, using a first optical slit of the laser beam sensor to generate a first electrical pulse, picking up the scan laser beam, at a second position, using a second optical slit of the laser beam sensor to generate a second electrical pulse, picking up the scan laser beam, at a third position, using a third optical slit of the laser beam sensor to generate a third electrical pulse, and determining a spot size and a position of the laser beam based on the first to third electrical pulses.