Meehan, Alexis wrote:
>
> My company is investigating the use of entec versus gold immersion. Our
> assembly
> house is pushing for gold immersion, however, I believe entec is lower in
> cost, right?
> What are your experiences with either of these processes? Thanks in advance.
>
> **************************************
> Alexis Meehan               Wavespan Corporation
> Engineering Services    500 N. Bernardo Avenue
> Tel: 650-237-8365            Mountain View, CA 94043
> Fax: 650-919-0191            http://www.wavespan.com
> **************************************
>

Alexis,

I have a sheet from Tyco (Logan Division) on the Electroless
Nickel/Immersion Gold Process.  Some of the advantages it lists (over
OSP coating) is longer shelf life, multiple soldering passes are
possible, and no special handling is required.  It also indicates a cost
index of 1 for HASL, OSP and Immersion Gold (IG).  Obviously they are
recommending IG and are set up for it. Your board vendor costs could be
different.

We used IG on one board so far.  Our QA folks are concerned about the
reliability of the solder joints and the possibility of brittle joints,
so I don't know if we will stick with it.

The Tyco sheet listed 2 technical papers that I have been unable to find
(maybe I don't know the right place to look):

  "An Investigation into the characteristics of Solderable Coatings for
Printed Circuit Boards" K.J. Whitlaw

  "Effect of Au on the Reliability of Fine Pitch Surface Mount Joints,"
J. Glazer, P.A. Kramer & J.W. Morris Jr.

If anyone knows where to find these papers, I'd like to read them or at
least let our QA folks read them - it might ease their minds about IG.

Hope this helps...

Ben Davis
Systems & Electronics Inc.
St. Louis, MO
[log in to unmask]

################################################################
DesignerCouncil E-Mail Forum provided as a free service by IPC using LISTSERV 1.8c
################################################################
To subscribe/unsubscribe, send a message to [log in to unmask] with following text in the body:
To subscribe:   SUBSCRIBE DesignerCouncil <your full name>
To unsubscribe:   SIGNOFF DesignerCouncil 
################################################################
Please visit IPC's web site (http://www.ipc.org) "On-Line Services" section for additional information.
For technical support contact Hugo Scaramuzza at [log in to unmask] or 847-509-9700 ext.312
################################################################