Laser Dicing Path Correction for Deformed Wafer Streets
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Solution Overview
Problem
Existing device chip production methods using laser processing can cause deformation of streets in workpieces, leading to damage and defective division due to the formation of modified layers along planned dividing lines, which may result in improper irradiation of devices with the laser beam.
Innovation Solution
A device chip production method and laser processing apparatus that includes forming modified layers along planned dividing lines while correcting for the position coordinates of the key patterns P, and correcting the planned dividing lines based on the position coordinates of the key patterns P, and correcting the planned dividing lines using a laser beam along the corrected planned dividing lines. The method involves forming a modified layer inside the workpiece by irradiating it with a laser beam, and correcting the planned dividing lines based on the position coordinates of the key patterns P, and correcting the laser beam to form the modified layer along the corrected planned dividing lines.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a modified layer is formed along a planned dividing line by laser irradiation, then the workpiece can be divided into device chips, but the mechanical strength of surrounding regions decreases causing the workpiece to expand and deform, resulting in curved streets that lead to device damage and defective division
Solution Approach 1:
The patent applies preliminary action by performing position coordinate acquisition and planned dividing line correction before laser irradiation. The control unit acquires position coordinates of key patterns, corrects the planned dividing line based on these coordinates, and then performs laser irradiation along the corrected line. This preliminary correction prevents street curvature and device damage by accounting for workpiece deformation before it occurs during the division process
Solution Approach 2:
The patent implements feedback by using the position coordinates of key patterns to correct the planned dividing line. The control unit continuously monitors the actual positions of key patterns and adjusts the irradiation path accordingly. This feedback mechanism ensures that even when workpiece deformation occurs, the laser beam remains aligned with the correct dividing line, preventing device damage and ensuring accurate chip division
2Reliability
If the workpiece is irradiated with a laser beam along a curved street, then division may be achieved, but devices may be irradiated with the laser beam causing damage
Solution Approach 1:
The control unit performs preliminary correction of the planned dividing line by acquiring position coordinates of key patterns before laser irradiation. This preliminary action calculates the correct irradiation path that accounts for potential workpiece deformation, ensuring the laser beam follows the accurate dividing line and avoids irradiating devices, thus preventing damage while ensuring successful division
Solution Approach 2:
The system uses feedback from key pattern position coordinates to continuously adjust the planned dividing line. The control unit compares the actual positions of key patterns with their expected positions and corrects the irradiation path accordingly. This feedback mechanism ensures the laser beam precisely follows the corrected dividing line, preventing device damage while maintaining high division success rate
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 reduces damage to devices and prevents defective division by ensuring accurate laser irradiation along the corrected planned dividing lines, even when streets are deformed, thereby improving the production process.
Implementation Method 1
irradiating the workpiece with a laser beam having a wavelength that transmits through the workpiece to form a modified layer inside the workpiece
Data Source
AI summary
A method includes: a first processing step of forming a modified layer inside a workpiece by irradiating the workpiece with a laser beam having a wavelength that transmits through the workpiece along a first planned dividing line; a second processing step of forming a modified layer inside the workpiece by irradiating the workpiece with the laser beam along an adjacent planned dividing line adjacent to the first planned dividing line; and a position coordinate acquisition step of acquiring a position coordinate of a key pattern formed in a predetermined region of the workpiece along an extending direction of the adjacent planned dividing line, after the first processing step is performed, and in the second processing step, the adjacent planned dividing line is corrected based on the position coordinate of the key pattern, and the workpiece is irradiated with the laser beam along the corrected adjacent planned dividing line.