Now that abbreviations like SMT (surface mount technology) and LF (lead-free) are so well established in our vocabulary, it will soon be time to replace them with a couple of new ones: 3-D Assembly (3DA?) and solder-free (SF). The two are inextricably linked and, together, they will transform the electronic industry manufacturing infrastructure.  

Solder-free and 3-D will:

• Cut labor costs;
• Increase manufacturing productivity;
• Restore and extend equipment reliability; and
• Vastly reduce energy usage and carbon footprints.

But, above all, they will help bridge the circuit performance and density gaps needed to extend Moore's Law, as lithography on silicon runs out of steam. We will need that bridge while all those R&D labs search for silicon's replacement. 

Solder-free and 3-D assembly will offer America a golden, once-in-a-lifetime opportunity to restore her electronic manufacturing mojo. Please, America, don't blow this opportunity to leap-frog the rest of the world!

It's Time to Use 3-D in Electronic Assembly Architecture

First, I want to note "Will 3D ICs Replace PCBs?" written by Happy Holden. The article was featured in the November 1, 2007 issue of CircuiTree. The remarkable article was prescient, but slightly mistitled. I took an enormous liberty and re-titled it "How 3-D Assembly Will Short-Circuit HDI." That requires an explanation that, in turn, requires a short journey down electronic packaging/assembly memory lane... 

A Short History of Electronic Packaging and Assembly

The 1980s were the glory years for American electronic manufacturing, even as the offshoring process loomed in the background (see one of my previous columns, "From Hong Kong, 1963, to Del Mar, 2010: An Offshoring Reversal?"). Driven by increasing integrated circuit density reflected in IC packages, printed circuit fabrication discovered the third dimension in its initial multilayer circuit implementation.

At the assembly level, surface mount technology ratcheted up subsystem level density. But, by the end of the 1980s, the gap between <100 nanometer feature dimensions on silicon and > 6 mil (150 micrometer) on PCBs--three orders of magnitude difference--was growing even larger. That presented several roadblocks to progress toward the goals of higher performance electronic equipment with more functionality. 

In portable consumer electronics, "smaller, lighter, thinner" was the market imperative. So, at the end of the 1980s, and the beginning of the 1990s, all the sages of electronics packaging discovered a new religion. Their epiphany was called "multi-chip modules," bare, unpackaged die on board. Well, to shorten a long story, it didn't happen. MCMs didn't become main stream. The problem of "known good die" was a major impediment. But two related developments in the ‘90s did grab the densification action--array IC packages (BGA) using flip chip interconnections and HDI.