Laser Patterning & Metallization to Reduce Process Steps for PCB Manufacturing


Reading time ( words)

Abstract

Glass offers a number of advantages as a dielectric material, such as a low coefficient of thermal expansion (CTE), high dimensional stability, high thermal conductivity and suitable dielectric constant. These properties make glass an ideal candidate for, among other things, package substrate and high-frequency PCB applications. We report here a novel process for the production of printed circuit boards and integrated circuit packaging using glass as both a dielectric medium and a platform for wiring simultaneously.

An ultrafast laser is used to etch away the desired pattern (pads, wires and vias) in the glass, and copper plating is “seeded” through the laser-based deposition of copper droplets. The seeded area is then plated using electroless plating followed by electroplating. Demonstrations of fine pitch wires, variable diameter through holes and blind vias, and a multilayer stack are shown. The deposits have a resistivity less than a factor of 1.5x that of bulk copper for 5-10 mm wires. Plated lines in borosilicate glass of 7-10 μm width and 5-20 μm depth and line spacing down to ~10 μm are demonstrated, as well as vias with a top diameter approaching 100 μm for 150 μm glass and 40 μm for 50 μm glass.

The process presents the potential for significant material savings in terms of base materials, process chemicals, and waste disposal/recycling costs (glass is on the order of 100-fold less expensive than some current high-frequency dielectrics, and wet processes account for a large part of standard PCB/substrate manufacturing). Additionally, the processes are amenable toward other dielectric materials such as FR-4, polyimide and PTFE-based materials.

Introduction

Increased demand for high data transmission rates is driving the development of smaller PCB features. Electrical circuits are reaching the physical limitations of traditional PCB dielectric materials under which electromagnetic compatibility can be controlled.

To read the full version of this article which appeared in the August 2017 issue of The PCB Magazine, click here.

Share


Suggested Items

Ventec Keeps 'Shaking Things Up' with tec-speed 20.0

09/10/2018 | Barry Matties, I-Connect007
At the EIPC summer conference, I-Connect007 Publisher Barry Matties caught up with Ventec Europe & Americas COO Mark Goodwin, who provided an update on Ventec’s new products, the current state of the company, and how Ventec is shaking things up in the materials marketplace.

PCBs Are Moisture-Sensitive Devices

09/07/2018 | Richard Heimsch, SUPER DRY
Research by SMT & Hybrid GmbH (now SMT Elektronik) was conducted just prior to the original publication of IPC-1601, which now provides detailed guidelines for the packaging and storage of PCBs, both from the PCB manufacturer and at the assembler’s manufacturing floor.

PCB Design, Fabrication and Use from the Mil-Aero End-User Perspective

08/28/2018 | Pete Starkey, I-Connect007
The procedures described for Rolls Royce were directly comparable with those described for MBDA, and the presenters were unanimous in re-emphasising the importance of working closely with their chosen PCB fabricators at all levels and all stages of design, qualification and production of their circuit boards.



Copyright © 2018 I-Connect007. All rights reserved.