Two-Stage Laser Structuring for Dielectric PCB Substrates
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Solution Overview
Problem
Current laser-based methods for manufacturing advanced printed circuit boards are inefficient due to the high cost and limited flexibility of excimer lasers, which struggle to create structures of varying depths and sizes effectively, leading to slow processing rates and high operational costs.
Innovation Solution
A two-stage process using a solid state laser with a mask and beam scanner to form structures at different depths, allowing for high-speed scanning and separate optimization of each process step, thereby reducing costs and improving flexibility without relying on expensive excimer lasers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If direct write approach using UV DPSS laser is used, then fine groove scribing and depth control are improved, but processing speed for large area pads and ground planes deteriorates
Solution Approach 1:
The invention segments the laser processing into two distinct stages: a first laser process for creating grooves and pads to a first depth, and a second laser process for creating deeper contact holes. This segmentation allows each process to be optimized independently - the first process can use higher power for faster large-area processing, while the second process can use highly focusable beams for precise deep hole drilling, thereby resolving the contradiction between fine groove precision and processing speed.
2Productivity
If mask imaging approach using UV excimer laser is used, then processing speed for large area pads is improved, but cost and flexibility deteriorate
Solution Approach 1:
The invention replaces the expensive UV excimer laser with a more economical UV DPSS laser system. While excimer lasers are costly and require complex maintenance, the DPSS laser using diode pumping provides a more affordable, maintenance-friendly alternative that achieves comparable processing speeds for large-area structures through the two-stage process, thereby reducing device complexity and operational costs.
3Device complexity
If single laser process is used, then process simplicity is improved, but ability to form structures at different depths deteriorates
Solution Approach 1:
The invention divides the laser processing into two sequential laser processes, each optimized for specific depth requirements. The first process forms grooves and pads to a controlled first depth, while the second process creates deeper contact holes. This segmentation enables precise depth control for different structure types without requiring complex single-laser parameter adjustments, maintaining process simplicity while enhancing depth adaptability.
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 formation of fine-scale structures at multiple depths efficiently and cost-effectively, enhancing processing speed and reducing capital and operating expenses compared to traditional methods.
Implementation Method 1
lasers are used to directly ablate fine grooves, larger area pads and also contact holes in organic dielectric substrates
Data Source
AI summary
Apparatus and methods for forming fine scale structures (4, 4′, 4″, 5, 6, 7, 8) in the surface of a dielectric substrate (3) to two or more depths are disclosed. In an example, the apparatus comprises a first solid state laser (12) arranged to provide a first pulsed laser beam (13), a first mask (16) having a pattern for defining a first set of structures (4, 6, 7, 8) at a first depth, a projection lens (17) for forming a reduced size image of said pattern on the surface (3) of the substrate and a beam scanner arranged to scan said first pulsed laser beam (13) in a two-dimensional raster scan relative to the first pattern to form a first set of structures (4, 6, 7, 5) at a first depth in the substrate, wherein the first or a further solid state laser is arranged to form a second set of structures (8) at a second depth in the substrate (3).