Pulsed Laser Groove Processing With Sustained Plasma Debris Control
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Solution Overview
Problem
Laser processing apparatuses face challenges in simultaneously forming grooves in workpieces and removing melted debris and growing debris, which degrades the quality of device chips.
Innovation Solution
A laser processing apparatus that uses pulsed laser beams to form grooves and break growing debris while restraining melted debris production, by controlling the timing and frequency of laser beam application to manage plasma generation and heat dissipation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a laser beam is applied to a workpiece for forming grooves, then groove formation is achieved, but melted debris and growing debris are produced which degrade device chip quality
Solution Approach 1:
The patent applies periodic pulsed laser beams with specifically controlled time intervals. The pulse width is set to 100ps to 10ns and the time interval between pulses is controlled to maintain plasma without interruption. This periodic action allows the laser to break growing debris and restrain melted debris formation while continuing groove formation, thus resolving the contradiction between groove formation accuracy and debris generation.
Solution Approach 2:
The patent changes key parameters including pulse width (100ps to 10ns), time interval between pulses, and laser wavelength (355nm). By optimizing these parameters, the laser processing achieves both effective groove formation and debris control. The specific parameter range ensures that plasma is sustained without interruption to break growing debris while preventing melted debris accumulation.
2Manufacturing precision
If a laser beam is applied again to remove melted debris and growing debris, then device chip quality is improved, but productivity decreases
Solution Approach 1:
The patent merges the groove formation process with the debris removal process into a single simultaneous operation. By applying pulsed laser beams with controlled time intervals during the groove formation itself, the plasma breaks growing debris and restrains melted debris formation in real-time. This eliminates the need for a separate debris removal step, thus maintaining device chip quality while improving productivity.
Solution Approach 2:
The patent ensures continuous plasma generation by controlling the time interval between pulsed laser beams. This continuous plasma action continuously breaks growing debris and restrains melted debris formation throughout the groove formation process. The useful action of debris management continues without interruption alongside groove formation, eliminating idle time and improving overall productivity.
3Productivity
If pulsed laser beams are applied with high frequency, then productivity is improved, but heat accumulation occurs which degrades device quality
Solution Approach 1:
The patent uses periodic pulsed laser beams with optimally controlled time intervals between pulses. This periodic action allows sufficient time for heat dissipation between pulses while maintaining continuous plasma generation. The pulse width of 100ps to 10ns and carefully selected time intervals ensure that productivity is maximized without causing harmful heat accumulation that would degrade device quality.
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 approach increases productivity by allowing simultaneous groove formation and debris management, preventing heat accumulation that could degrade device quality.
Implementation Method 1
within a period of time after which a plasma generated from the workpiece by the pulsed laser beam applied thereto becomes extinct, a next pulsed laser beam is applied to the workpiece to sustain the plasma uninterruptedly to break growing debris
Implementation Method 2
applying pulsed laser beams to the workpiece held on the chuck table... heat generated by the application of the pulsed laser beams
Implementation Method 3
forming grooves in the workpiece by way of ablation by applying the pulsed laser beams to the workpiece
Implementation Method 4
a beam condenser for converging the pulsed laser beams emitted from the laser oscillating mechanism and applying the converged pulsed laser beams to the workpiece
Data Source
AI summary
A laser processing apparatus includes a laser oscillating mechanism for emitting pulsed laser beams. The laser oscillating mechanism includes a group setting section for establishing the number of pulsed laser beams to be applied to a workpiece until a time after which melted debris produced by the pulsed laser beams applied to the workpiece is solidified, and assigns the pulsed laser beams to a group, under conditions that, within a period of time which is shorter than a period of time in which the melted debris is produced, and within a period of time after which a plasma generated by the pulsed laser beam becomes extinct, a next pulsed laser beam is applied to the workpiece to sustain the plasma uninterruptedly to break growing debris, and a time interval setting section for establishing a time interval between the group and another group adjacent thereto.