Wafer Laser Processing with Height Measurement and Alignment
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current laser processing methods for wafer cutting lack precision and efficiency, particularly in aligning and focusing the laser beam within the wafer, leading to potential defects and reduced processing accuracy.
Innovation Solution
A laser processing method and apparatus that includes loading a wafer on a work stage, determining chip number and inspecting for defects, aligning the wafer, measuring surface height, monitoring laser power, and adjusting the work stage's position to precisely focus the laser beam within the wafer, allowing for horizontal and vertical movement and rotation to ensure accurate cutting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the laser beam is focused on the wafer surface without precise alignment, then the processing speed is maintained, but the manufacturing precision and defect rate are degraded
Solution Approach 1:
The system performs preliminary alignment actions by measuring the wafer surface height using a displacement sensor before laser processing begins. The work stage position is adjusted in advance to ensure the focal point is correctly positioned inside the wafer, preventing focusing errors before they occur during processing.
Solution Approach 2:
The system uses a displacement sensor to measure the actual wafer surface height and provides feedback to the control system. This feedback enables real-time adjustment of the work stage vertical position to maintain precise focal point positioning inside the wafer throughout the processing operation.
2Measurement precision
If the work stage is made adjustable in multiple directions, then the alignment precision is improved, but the device complexity increases
Solution Approach 1:
The work stage is designed with multi-functionality, incorporating horizontal transfer units for X-Y positioning, a z-axis transfer unit for vertical positioning, and an angle adjustor for rotational alignment. This single integrated work stage structure performs multiple alignment functions that would otherwise require separate devices, improving precision while controlling overall system complexity.
3Manufacturing precision
If the focal point is positioned inside the wafer rather than on the surface, then the manufacturing precision is improved, but the device complexity increases due to additional adjustment mechanisms
Solution Approach 1:
The system employs a displacement sensor that automatically measures the wafer surface height and enables the control system to self-adjust the work stage vertical position. This self-service mechanism automatically positions the focal point inside the wafer without requiring manual intervention or complex mechanical adjustment mechanisms, maintaining ease of operation while achieving precise focusing.
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 method and apparatus significantly reduce defect rates by ensuring precise alignment and focusing of the laser beam, enhancing the accuracy and efficiency of wafer processing while maintaining the focal point inside the wafer.
Implementation Method 1
a laser processing apparatus adapted to focus a laser beam on a wafer to be processed via a lens
Implementation Method 2
focus a laser beam on a wafer to be processed via a lens
Implementation Method 3
a work stage connected to a vacuum unit and securing the wafer using negative pressure
Data Source
AI summary
The present disclosure relates to laser processing and a laser processing apparatus for processing materials using laser. Processing performed after loading a wafer on a work stage and a laser processing apparatus for implementing such processing, among others, are disclosed. The laser processing includes loading a wafer on a work stage; determining the number of chips formed on the wafer loaded on the work stage, performing chip defect inspection and aligning the wafer while moving the work stage; measuring a height of a surface of the wafer loaded on the work stage using a displacement sensor; monitoring output power of a processing laser using a power meter; and shifting the work stage while irradiating a laser beam on the wafer to process the wafer.