Dual Condenser Laser Processing Apparatus for Wafer Dicing
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Solution Overview
Problem
Laser processing apparatuses experience standby time inefficiencies when switching between dicing lines, reducing overall processing throughput.
Innovation Solution
The apparatus employs two condensers and a switching mechanism with a ½ wavelength plate, polarizing beam splitter, and mirror to simultaneously process one dicing line while indexing the other condenser to the next line, allowing continuous laser application without interruption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a single condenser is used to process the wafer along projected dicing lines, then the device complexity is low, but standby time increases and productivity decreases
Solution Approach 1:
The patent divides the single condenser into multiple separate condensers (first condenser and second condenser) that can operate independently. Each condenser is assigned to process different dicing lines, allowing parallel processing operations and eliminating the standby time that occurs when a single condenser must move between lines.
Solution Approach 2:
The patent positions the first and second condensers in advance at different Y-direction locations corresponding to different dicing lines. While one condenser is processing a dicing line, the other condenser is already pre-positioned and ready to immediately begin processing the next line, eliminating the need for standby time during transitions.
2Productivity
If the chuck table is indexing-fed in the Y direction to bring the next dicing line into alignment, then the laser beam can be applied to the next line, but processing time is lost during the indexing feed operation
Solution Approach 1:
The patent pre-positions the second condenser in the Y direction to align with the next dicing line before the first condenser finishes processing the current line. This preliminary positioning allows the system to immediately switch to the second condenser for continuous processing without losing time during indexing feed operations.
Solution Approach 2:
The patent maintains continuous laser processing by having one condenser always engaged in processing while the other is being repositioned. The switching mechanism ensures that the laser beam is continuously applied to different dicing lines without interruption, eliminating the standby time that would occur during table indexing operations.
3Productivity
If two condensers are used to process multiple dicing lines simultaneously, then standby time is reduced and productivity increases, but the device complexity and switching mechanism complexity increase
Solution Approach 1:
The patent introduces a switching mechanism that includes a ½ wavelength plate, polarizing beam splitter, and mirror as intermediary optical components. These components act as mediators to direct the laser beam from a single laser oscillator to either the first or second condenser based on the processing requirements, managing the complexity of switching between multiple condensers.
Solution Approach 2:
The patent uses a ½ wavelength plate that can rotate to change the polarization state of the laser beam. By rotating the wavelength plate to different angles, the system switches between directing the laser beam to the first condenser or the second condenser, providing a simple parameter-based switching mechanism that controls the complexity of managing multiple condensers.
4Productivity
If a single laser beam path is used, then the device complexity is low, but the ability to process multiple dicing lines continuously is limited
Solution Approach 1:
The patent creates a universal laser beam delivery system where a single laser oscillator can serve multiple condensers through the switching mechanism. The optical path configuration with the ½ wavelength plate, polarizing beam splitter, and mirror allows one laser source to functionally become multiple independent beam paths, enabling continuous processing of multiple dicing lines without requiring separate laser oscillators for each condenser.
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 configuration significantly reduces standby time, enabling successive processing sessions and enhancing processing efficiency by maintaining continuous laser application across multiple dicing lines.
Implementation Method 1
a 1/2 wavelength plate, rotating means for turning the 1/2 wavelength plate selectively to a first angle and a second angle
Implementation Method 2
a polarizing beam splitter configured to reflect 100% an S-polarized laser beam whose plane of polarization has been rotated by the 1/2 wavelength plate
Implementation Method 3
processing means for processing the wafer held on the holding table with the laser beam which is focused at a processing point along the projected dicing lines
Data Source
AI summary
A laser processing apparatus includes a laser oscillator configured to oscillate a laser beam, a first condenser configured to focus an S-polarized laser beam, a second condenser configured to focus a P-polarized laser beam, an X-moving unit configured to processing-feed a holding table that holds a wafer thereon in X directions, and first and second indexing feed units configured to indexing-feed the first and second condensers respectively in Y directions. While the wafer is being processed with the laser beam from the first condenser along a projected dicing line on the wafer in the X directions, the second condenser is indexing-fed and positioned on a next projected dicing line along which to process the wafer.