Laser Beam Positioning System for High-Throughput Processing
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Solution Overview
Problem
Conventional laser processing systems face challenges in achieving high throughput while maintaining accuracy and quality when processing densely spaced workpiece features due to dynamic and thermal loads on laser beam positioning and optical components, particularly in applications like solar cell processing where high precision and rapid drilling of vias are required.
Innovation Solution
A laser processing system that incorporates a movable stage and two beam positioners, including a zero-inertia acousto-optic deflector and a mirror-based beam positioner, to rapidly position the laser beam within a smaller scan field, minimizing acceleration and deceleration of the galvanometer head, and allowing the processing laser beam to dwell at each feature location within its inter-pulse period, thereby increasing throughput and reducing thermal accuracy issues.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If a single large galvo field is used to cover the entire workpiece, then the processing area is increased, but the accuracy is degraded due to optics heating and large beam diameter requirements
Solution Approach 1:
The patent divides the large workpiece area into multiple smaller scan fields, each processed by a compact galvo system. The workpiece is systematically divided into regions that can be sequentially accessed, allowing each galvo to operate within its optimal accuracy range while collectively covering the entire large area through coordinated positioning.
2Manufacturing precision
If a smaller galvo field is used with a movable stage, then the galvo accuracy is improved, but the throughput is reduced due to frequent acceleration and deceleration
Solution Approach 1:
The patent pre-calculates and pre-positions the galvo head at optimal locations before processing begins. The system plans the entire scanning trajectory in advance, organizing the scan pattern to minimize the number of stop-start cycles. This preliminary planning allows the galvo to maintain higher velocities between feature locations while still achieving precise positioning, thereby improving throughput without sacrificing accuracy.
3Productivity
If high acceleration is used to reduce galvo turnaround time, then the throughput is increased, but thermal heating degrades accuracy and limits achievable acceleration
Solution Approach 1:
The patent implements a continuous scanning mode where the galvo head maintains motion throughout the processing cycle, eliminating complete stops between feature locations. By organizing the scan pattern to allow continuous or near-continuous traversal of the workpiece area, the system reduces the frequency of high-acceleration events while maintaining high throughput. The laser beam is modulated to process features during the continuous scan, converting a stop-start process into a continuous operation.
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 enables high-throughput processing of densely spaced workpiece features with improved accuracy and quality by eliminating move time between feature locations and reducing thermal loading on optical components, thus meeting the high throughput requirements of applications like solar cell processing.
Implementation Method 1
The second beam positioner includes a zero-inertia optical deflector of an acousto-optic type characterized by a second response time and operable to move the processing beam to locations within the scan field region
Data Source
AI summary
A method of accomplishing high-throughput laser processing of workpiece features arranged in a densely spaced pattern minimizes workpiece feature processing inaccuracy and quality degradation that result from dynamic and thermal loads on laser beam positioning and optical components directing the laser beam during workpiece feature processing. A preferred embodiment is implemented with a laser beam positioning system composed of a zero-inertia optical deflector of an acousto-optic beam deflector (AOD) or an electro-optical deflector (EOD) type, a galvanometer head, and a linear stage cooperating to position the laser beam among the workpiece features.