Saturday, January 30, 2010

PCB International: An Introduction

Hello, my name is Michael. I am the writer for the official blog of PCB International. First I'd like to tell you a little about our company. PCB International is a west-coast based Printed Circuit Board supplier. We are equipped with leading edge technology to meet with all your PCB needs. We specialize in the whole breadth of orders from prototype to production runs. More information can be found at

The goal of this blog is to allow our current and prospective customers and anyone else interested in PCBs a glimpse into the happenings at our company and also to comment on everything PCB related. This blog will be updated regularly so be sure to check back frequently. Comments are very much encouraged.

Saturday, December 19, 2009



Wednesday, December 16, 2009

Surface Finish Pros and Cons

As a reminder, one of the focuses of this blog is to go over the technologies involved in PCB manufacturing. Today, I'd like to talk about a critical component in printed circuit board manufacturing - the surface finish. Surface finishes form a crucial interface between the components to be mounted and the interconnection circuitry.

As its most essential function, the final finish process is intended to provide exposed copper circuitry with a protective coating in order to preserve solderability. In a more expanded view, the final finish coating is required to meet dozens of functional criteria, including solderability, environmental, electrical, physical, and durability demands. The past decades have brought about a wholesale transformation in this segment of the industry - a wide variety of functional, environmental, engineering, cost, productivity, and failure mode issues have contributed to this frequent change.

Nonetheless, years of manufacturing experience and constant innovation has enabled PCB International to be a leading edge provider for all your surface finish needs. Including, but not limited to: HASL, ENIG (Immersion Gold), Organic solderability preservative (OSP), immersion silver, immersion tin, Electrolytic nickel/electrolytic gold, electroless gold, etc. Below lists the pros and cons of a number of the more popular surface finishes - most relevant in today’s applications. Please note that all of these are available at PCB International!

Pros & Cons of HASL




Environment Consequences

Cu/Sn solderjoint

Poor fine pitch assembly


Solder bridging

Widespread availability

Plugged PTH

Thermal damage to board

Not Flat

Thick intermetallics

Pros & Cons of Immersion Gold (ENIG)



Pb Free

Comparatively expensive

No copper dissolution

Brittle Ni/Sn solderjoint

Surface contacts

Signal loss at RF frequencies

Long shelf life

Black-pad, black-line nickel

Strong PTH "rivet"

Solder Mask "attack"

Fine pitch assembly

Not re-workable

Widespread availability

Comparatively complicated

Pros and Cons of Organic Solderability Preservative (OSP)



Least expensive finish

Handling sensitive

Flat, fine pitch assembly

Poor PTH soldering

relatively simple process

Shorter shelf life

Widespread availability

Degrades with multiple reflow

Cu/Sn solderjoint

No direct thickness measurement

Pb free

High surface contact resistance

High productivity at fabrication

Not inspect able prior to assembly


Exposed copper on final assembly

Pros and Cons of Immersion Silver



Flat, fine-pitch assembly


Comparatively inexpensive finish

Attack at solder mask interface

No Pb

Dendrite formation


Exposed silver can corrode

Easy thickness measurement

Solder joint microvoid history

Excellent surface contact functionality

Handling Sensitive

No degradation with multiple soldering reflow

High productivity at fabrication

Pros and Cons of Immersion Tin



Flast, fine-pitch assembly

Handling sensitive

Comparatively inexpensive finish

Solder mask attack

No Pb

Corrosion of Whiskers


Difficult thickness measurement

Multiple reflow soldering

Degredation with time/heat

Less visible tarnish

Use of thiourea