Saturday, January 30, 2010
PCB International: An Introduction
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
Pros & Cons of HASL | |
Pro | Cons |
Inexpensive | Environment Consequences |
Cu/Sn solderjoint | Poor fine pitch assembly |
Re-workable | Solder bridging |
Widespread availability | Plugged PTH |
Thermal damage to board | |
Not Flat | |
Thick intermetallics | |
Pros & Cons of Immersion Gold (ENIG) | |
Pros | Cons |
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) | |
Pros | Cons |
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 |
Re-workable | Exposed copper on final assembly |
Pros and Cons of Immersion Silver | |
Pros | Cons |
Flat, fine-pitch assembly | Tarnish |
Comparatively inexpensive finish | Attack at solder mask interface |
No Pb | Dendrite formation |
Re-workable | 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 | |
Pros | Cons |
Flast, fine-pitch assembly | Handling sensitive |
Comparatively inexpensive finish | Solder mask attack |
No Pb | Corrosion of Whiskers |
Functionality | Difficult thickness measurement |
Multiple reflow soldering | Degredation with time/heat |
Less visible tarnish | Use of thiourea |
Reworkable |