Pulsed Laser Groove Processing With In-Situ Debris Breaking
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Solution Overview
Problem
Existing laser processing methods for wafers with copper interconnects on silicon substrates face issues with debris formation due to laser beam irradiation, leading to decreased device quality, as they require separate processes for forming grooves and breaking growing debris, which reduces productivity.
Innovation Solution
A laser processing apparatus and method that simultaneously execute laser beam irradiation for forming grooves and breaking growing debris using a pulsed laser beam system with a group setting part and time interval setting part, ensuring irradiation occurs after plasma disappearance and heat cooling, allowing for efficient debris removal during groove formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If separate processes are used for groove formation and debris removal, then device quality is maintained, but productivity decreases
Solution Approach 1:
The patent combines groove formation and debris removal into a single laser irradiation process by controlling the pulse interval to coincide with plasma disappearance timing, enabling simultaneous execution of both functions and improving productivity without compromising device quality
Solution Approach 2:
The patent employs periodic pulsed laser irradiation with specifically controlled pulse intervals, where the interval between pulses is set to match the plasma disappearance timing, creating a periodic action that effectively removes debris while maintaining processing efficiency
2Reliability
If laser beam irradiation is executed again to break growing debris, then device quality is improved, but processing time increases
Solution Approach 1:
The patent performs debris-breaking action during the groove formation process itself by controlling plasma generation and disappearance timing, rather than performing a separate subsequent irradiation step, thus achieving preliminary debris removal that eliminates additional processing time
Solution Approach 2:
The patent maintains continuous useful action by executing debris removal during the groove formation process through controlled plasma phenomena, eliminating idle time between groove formation and debris removal operations
3Productivity
If pulsed laser beam irradiation is used for simultaneous groove formation and debris removal, then productivity is improved, but control complexity increases
Solution Approach 1:
The patent controls the pulse interval parameter of the laser irradiation to specifically match plasma disappearance timing, using parameter optimization to achieve dual functionality without requiring complex additional control mechanisms
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 improves productivity by enabling simultaneous groove formation and debris removal, enhancing device quality by preventing heat-induced damage and reducing processing time.
Implementation Method 1
forming grooves by ablation processing by irradiating the workpiece with the pulsed laser beams
Implementation Method 2
breaking, by plasma, growing debris formed in the groove forming step
Data Source
AI summary
A laser processing apparatus includes a chuck table that holds a workpiece, a laser beam irradiation unit that irradiates the workpiece with a laser beam, and a feed mechanism that moves the chuck table and the laser beam irradiation unit relative to each other to execute processing feed. The laser beam irradiation unit includes a laser oscillation mechanism that emits a pulsed laser beam and a beam condenser that condenses the pulsed laser beam emitted by the laser oscillation mechanism and irradiates the workpiece with the pulsed laser beam. The laser oscillation mechanism has a group setting part that sets multiple pulsed laser beams into one group and a time interval setting part that sets a time interval of the pulsed laser beams that configure the one group, and sets the repetition frequency in such a manner as to regard the one group as one unit.