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Current IssueThe Hole Truth: Via Integrity in an HDI World
From the drilled hole to registration across multiple sequential lamination cycles, to the quality of your copper plating, via reliability in an HDI world is becoming an ever-greater challenge. This month we look at “The Hole Truth,” from creating the “perfect” via to how you can assure via quality and reliability, the first time, every time.
In Pursuit of Perfection: Defect Reduction
For bare PCB board fabrication, defect reduction is a critical aspect of a company's bottom line profitability. In this issue, we examine how imaging, etching, and plating processes can provide information and insight into reducing defects and increasing yields.
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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.
Suggested Items
Trump Copper Tariffs Spark Concern
07/10/2025 | I-Connect007 Editorial TeamPresident Donald Trump stated on July 8 that he plans to impose a 50% tariff on copper imports, sparking concern in a global industry whose output is critical to electric vehicles, military hardware, semiconductors, and a wide range of consumer goods. According to Yahoo Finance, copper futures climbed over 2% following tariff confirmation.
Happy’s Tech Talk #40: Factors in PTH Reliability—Hole Voids
07/09/2025 | Happy Holden -- Column: Happy’s Tech TalkWhen we consider via reliability, the major contributing factors are typically processing deviations. These can be subtle and not always visible. One particularly insightful column was by Mike Carano, “Causes of Plating Voids, Pre-electroless Copper,” where he outlined some of the possible causes of hole defects for both plated through-hole (PTH) and blind vias.
Trouble in Your Tank: Can You Drill the Perfect Hole?
07/07/2025 | Michael Carano -- Column: Trouble in Your TankIn the movie “Friday Night Lights,” the head football coach (played by Billy Bob Thornton) addresses his high school football team on a hot day in August in West Texas. He asks his players one question: “Can you be perfect?” That is an interesting question, in football and the printed circuit board fabrication world, where being perfect is somewhat elusive. When it comes to mechanical drilling and via formation, can you drill the perfect hole time after time?
The Evolution of Picosecond Laser Drilling
06/19/2025 | Marcy LaRont, PCB007 MagazineIs it hard to imagine a single laser pulse reduced not only from nanoseconds to picoseconds in its pulse duration, but even to femtoseconds? Well, buckle up because it seems we are there. In this interview, Dr. Stefan Rung, technical director of laser machines at Schmoll Maschinen GmbH, traces the technology trajectory of the laser drill from the CO2 laser to cutting-edge picosecond and hybrid laser drilling systems, highlighting the benefits and limitations of each method, and demonstrating how laser innovations are shaping the future of PCB fabrication.
Day 2: More Cutting-edge Insights at the EIPC Summer Conference
06/18/2025 | Pete Starkey, I-Connect007The European Institute for the PCB Community (EIPC) summer conference took place this year in Edinburgh, Scotland, June 3-4. This is the third of three articles on the conference. The other two cover Day 1’s sessions and the opening keynote speech. Below is a recap of the second day’s sessions.