Laser Scribe Groove Processing With Dynamic Focal-Point Power Control
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Solution Overview
Problem
Existing laser processing methods for removing contaminants from grooves in semiconductor wafers are inefficient, as they require a fixed laser beam position and additional weak laser beams for cleaning, which can lead to incomplete removal and inflexibility in adjusting groove widths.
Innovation Solution
A laser processing machine with a controller and focal-point moving units that allows the laser beam to be focused and moved in specific directions to form grooves and remove contaminants simultaneously, adjusting power levels based on position to maintain groove integrity and flexibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a weak laser beam is additionally applied to remove contaminants from groove edges, then contaminant removal is achieved, but the method becomes inflexible when groove width needs to be changed and requires fixed diffraction grating configuration
Solution Approach 1:
The patent applies the dynamics principle by making the laser beam position adjustable through a focal point moving unit. Instead of using a fixed diffraction grating configuration, the system can dynamically change the laser beam position to match different groove widths. The controller adjusts the focal point position based on the width of the scribe line, enabling the same laser beam to effectively remove contaminants from grooves of varying widths without requiring physical reconfiguration of optical components.
2Productivity
If a fixed diffraction grating is used to split the laser beam for simultaneous groove formation and contaminant removal, then processing efficiency is improved, but the system becomes costly and inflexible
Solution Approach 1:
The patent applies parameter changes by controlling the position parameter of the laser beam focal point rather than using a fixed diffraction grating. The focal point moving unit changes the position parameter of the laser beam to match different groove widths, achieving the same effect as beam splitting but with a simpler, more cost-effective system. The controller adjusts the focal point position based on scribe line width, maintaining processing efficiency while reducing device complexity and cost.
3Ease of operation
If the laser beam position is not precisely adjusted to the groove edges, then the system remains simple to operate, but contaminant removal becomes ineffective
Solution Approach 1:
The patent applies feedback by having the controller automatically adjust the focal point position based on the width of the scribe line. The system receives information about the groove width and uses this feedback to position the laser beam focal point at the appropriate location for effective contaminant removal. This automated feedback mechanism ensures precise beam positioning without requiring complex manual adjustment procedures, maintaining ease of operation while ensuring reliable contaminant removal.
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
Enables effective removal of contaminants while forming grooves with high power on the center and low power on edges, allowing for flexible adjustment of the laser beam position without the need for diffraction gratings, improving the quality and precision of semiconductor wafer processing.
Implementation Method 1
the film is removed at its portions, which overlap the streets, by a processing method called 'laser ablation' that causes absorption of the laser beam into the workpiece
Implementation Method 2
causes absorption of the laser beam into the workpiece
Implementation Method 3
a condenser that focuses the laser beam, which has been generated by the laser oscillator, on the focal point
Data Source
AI summary
There is provided a laser processing machine for processing a workpiece having a scribe line set thereon. The processing machine includes a controller configured to perform a procedure of moving a focal point of a laser beam in a first moving direction, which intersects a processing feed direction, in a range of a width of the line when the focal point and the holding unit relatively move along the processing feed direction, and a procedure of controlling power of the laser beam so that, upon movement of the focal point in the first moving direction, the power of the laser beam is smaller when the focal point is located in regions on outer edge sides of the line than when the focal point is located in a region on a center side of the scribe, whereby a groove is formed along the line.