Real-Time Topography Tracking for Laser Via Drilling
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Solution Overview
Problem
Current methods for measuring the topography and thickness of sequentially laminated targets in laser machining are time-consuming and inadequate, leading to inconsistent via quality due to variations in layer thickness and topography, which can result in nonuniform via diameters, over-drilling, or incomplete via formation.
Innovation Solution
A tracking device, such as a laser triangulation, capacitance, or eddy current probe, is used to measure surface height and layer thickness in real-time, allowing the machining laser beam system to adjust its position and energy accordingly to maintain optimal focus and energy application for consistent via formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a probe or camera is used to measure target topography, then measurement capability is provided, but measurement time increases significantly
Solution Approach 1:
The system performs preliminary measurement of the entire target topography before via drilling begins. This upfront measurement captures all surface height variations, allowing the focus control system to pre-calculate and apply appropriate focus adjustments for each via location, eliminating the need for time-consuming measurements at each individual via site.
Solution Approach 2:
The patent replaces mechanical probe-based measurement systems with optical measurement methods. This substitution enables faster, non-contact measurement of target topography while maintaining measurement precision, thereby reducing measurement time without sacrificing accuracy.
2Loss of time
If a single location measurement is performed, then measurement time is reduced, but topography variations across the target are not accounted for
Solution Approach 1:
The system divides the target into multiple measurement regions and obtains topography data for each region. This segmented measurement approach captures local surface variations across the entire target, allowing the focus control system to apply location-specific focus adjustments that maintain via quality consistency throughout the target.
Solution Approach 2:
The system dynamically changes the focus parameter of the laser beam based on measured topography variations at different target locations. By adjusting the focus depth according to the specific surface height at each via location, the system maintains optimal focus conditions across varying topography, ensuring consistent via quality.
3Manufacturing precision
If layer thickness varies beyond the depth of focus range, then via quality deteriorates with nonuniform diameters, but adjusting focus for each variation increases processing time
Solution Approach 1:
The system implements a feedback loop where measured target topography and layer thickness information is used to dynamically adjust the laser focus depth and energy parameters. This real-time feedback ensures that each via is drilled with optimal focus settings matched to the local layer thickness, maintaining via diameter uniformity without requiring manual intervention or excessive processing time.
Solution Approach 2:
The system dynamically adjusts focus depth and laser energy parameters during the via drilling process based on pre-measured topography data. This dynamic adaptation allows the system to maintain optimal focus conditions for varying layer thicknesses across the target, ensuring consistent via quality while preserving high processing speeds through automated parameter control.
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 the production of higher quality vias by ensuring the depth of focus and energy application are accurately adjusted based on real-time measurements, improving the repeatability and quality of via drilling and material removal processes.
Implementation Method 1
A tracking device, such as a laser triangulation, capacitance, or eddy current probe, is used to measure surface height and layer thickness in real-time
Implementation Method 2
A tracking device, such as a laser triangulation, capacitance, or eddy current probe, is used to measure surface height and layer thickness in real-time
Implementation Method 3
A tracking device, such as a laser triangulation, capacitance, or eddy current probe, is used to measure surface height and layer thickness in real-time
Implementation Method 4
Lasers are used to drill vias in and remove material from electronic materials products
Data Source
AI summary
An efficient method of and a system for performing topography measurement facilitates increasing laser machining throughput. Topography measurements at multiple points on a target specimen or continuous real time measurement and monitoring of the target specimen surface topography and target specimen thickness can be performed during a laser machining process. Measurement of the thickness of the target specimen to be laser machined would permit fine tuning of laser energy delivered and result in higher quality target material removal.