Facing the Future: The Role of 5G and Beyond in Shaping PCB Demand
It’s Only Common Sense: Stop Pitching, Start Listening
Trouble in Your Tank: Causes of Plating Voids, Pre-electroless Copper
Lead-free Reflow for High-layer-count PCBs
June 17, 2014 | Happy Holden, Retired, and Michael Carano, OMG Electronic Chemicals, LLCEstimated reading time: 1 minute
This article is an update of the Holden-Carano article originally published in the February 2013 issue of The PCB Magazine.
Abstract
One of the most difficult printed circuit boards to adapt to Pb-free assembly processes is the high-layer count multilayer. Often, these multilayers have through-hole and hand-soldered components, and requirements for two or more rework cycles. The higher reflow temperatures and slower wetting of lead-free solders place an enormous strain on the laminate and copper-plated hole barrel. In many cases, the boards cannot be assembled reliably even with newer, higher thermal performance FR-4s.
One solution to this problem is to redesign the multilayer using current design rules and newer innovative fabrication technologies. This article will review four of these new and enabling technologies:
- Laser-drilled microvias;
- Routing BGA using channels;
- Contribution of new SMT connectors; and
- Layer assignment changes (architectures).
Microvias offer the most significant opportunity to reduce not only the layers and thicknesses of multilayers, but also their cost while improving their electrical performance and density. Several examples will illustrate these new opportunities. Since blind vias are surface phenomena, to get the maximum benefit from them, layer assignment for signal, ground and power need to be reviewed and alternative constructions considered. These blind vias, by reducing the number of through-holes, contribute to increase routing density that allows the lower layer usage. Finally, by replacing through-hole connectors with surface mount connectors, higher connector density and improved electrical performance can be realized.
The resulting new multilayers are not only thinner, cheaper, and easier to design, but are less costly and suitable for lead-free assembly.
Read the full article here.
Editor's Note: This article originally appeared in the April 2014 issue of The PCB Magazine.
Share on:
Suggested Items
RF PCB Design Tips and Tricks
05/08/2025 | Cherie Litson, EPTAC MIT CID/CID+There are many great books, videos, and information online about designing PCBs for RF circuits. A few of my favorite RF sources are Hans Rosenberg, Stephen Chavez, and Rick Hartley, but there are many more. These PCB design engineers have a very good perspective on what it takes to take an RF design from schematic concept to PCB layout.
Trouble in Your Tank: Causes of Plating Voids, Pre-electroless Copper
05/09/2025 | Michael Carano -- Column: Trouble in Your TankIn the business of printed circuit fabrication, yield-reducing and costly defects can easily catch even the most seasoned engineers and production personnel off guard. In this month’s column, I’ll investigate copper plating voids with their genesis in the pre-plating process steps.
Elephantech: For a Greener Tomorrow
04/16/2025 | Marcy LaRont, PCB007 MagazineNobuhiko Okamoto is the global sales and marketing manager for Elephantech Inc., a Japanese startup with a vision to make electronics more sustainable. The company is developing a metal inkjet technology that can print directly on the substrate and then give it a copper thickness by plating. In this interview, he discusses this novel technology's environmental advantages, as well as its potential benefits for the PCB manufacturing and semiconductor packaging segments.
Trouble in Your Tank: Organic Addition Agents in Electrolytic Copper Plating
04/15/2025 | Michael Carano -- Column: Trouble in Your TankThere are numerous factors at play in the science of electroplating or, as most often called, electrolytic plating. One critical element is the use of organic addition agents and their role in copper plating. The function and use of these chemical compounds will be explored in more detail.
IDTechEx Highlights Recyclable Materials for PCBs
04/10/2025 | IDTechExConventional printed circuit board (PCB) manufacturing is wasteful, harmful to the environment and energy intensive. This can be mitigated by the implementation of new recyclable materials and technologies, which have the potential to revolutionize electronics manufacturing.