Entek has a short shelf life, and may cause electrical problems with power
supply ciruits (reason unknown).
Also, if you have parts on both sides of the board they will have to be
soldered at the same time, the Entek will vaporize off of the pads when
exposed to reflow temperatures.
> -----Original Message-----
> From: Ben Davis [SMTP:[log in to unmask]]
> Sent: Thursday, February 18, 1999 2:14 PM
> To: [log in to unmask]
> Subject: Re: [DC] Entec vs Gold Immersion
>
> 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]
>
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