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

Plating on Silver: What’s Old is New Again

07/07/2022 | Denis Jacques, Technic Inc.
About three decades ago, immersion silver, a nitrate-based process, gained a lot of market share in the world of PCB final finishes. More economical than ENIG, flat, solderable, and conductive, it had everything going for it—everything but corrosion resistance in a harsh environment, that is. Champagne voids were also an issue, along with line reduction. But the worst drawback, the characteristic that made the part short over time, was creep corrosion. A build-up of copper sulfide salt that grows in contact with a sulfur-rich environment, heat, and moisture resulted in failures in the field. This was enough to scar the process for good.

EIPC Summer Conference 2022: Day 2 Review

06/29/2022 | Pete Starkey, I-Connect007
Örebro, Sweden on June 15 brought a bright and early start to Day 2 of the EIPC Summer Conference for those who had enjoyed the previous evening’s networking dinner, but had resisted the temptation to over-indulge or to carry on their long-awaited catch-up conversations with old friends into the small hours. All but a few were in their seats for 9 a.m., awake and attentive for Session 4 of the conference, on the theme of new process technologies, moderated by Martyn Gaudion, CEO of Polar Instruments.

EIPC Summer Conference 2022: Day 1 Review

06/28/2022 | Pete Starkey, I-Connect007
At last, a live EIPC conference and this time in the Swedish city of Örebro, “where history and contemporary culture converge,” a pleasant and convenient location for an event that included a privileged visit to the Ericsson facility in Kumla. Around 100 delegates made the journey and the Örebro Scandic Grand Hotel was an excellent conference venue for the June 14-15 conference.



Copyright © 2022 I-Connect007. All rights reserved.