I would not say that there are no dearer deposit methods Wally .
And you're right on fine control on high first pass yields demands it
does justify itself .
But we'd have it uphill to convince Kathy with 99.3 on silver on first
go to switch over .
We just passed 50K on switch pad (carbon pill) life cycle ; this silver
is even versatile on contact .
Steam to follow . That is AlphaLevel .
It is interesting the top organic coat does have little effect on
resistance .
>----------
>From: Wally Doeling (wallyd)[SMTP:[log in to unmask]]
>Sent: Thursday, 14 May 1998 9:37
>To: Paul Klasek; 'TechNet E-Mail Forum.'
>Cc: Wally Doeling (wallyd)
>Subject: RE: [TN] HASL alternatives
>
> The PPT process is very useful for controlling solder deposits
>especially on fine pitch and micro-BGA parts as well as on very fine designs
>used for direct chip attach using a CC-4 approach.
> This process provides a very defined volume of solder which cannot be
>accomplished by normal stencil printing and if that is your goal, I think
>that the economics work out very well. The cost is a lot less than you will
>get with other
>solder deposit methods I have looked at!
>
> Contact: JoAnne DeBlis
> 714-557-3383
>
> [log in to unmask]
>
>
> -----Original Message-----
> From: Paul Klasek [SMTP:[log in to unmask]]
> Sent: Wednesday, May 13, 1998 3:45 PM
> To: [log in to unmask]
> Subject: Re: [TN] HASL alternatives
>
> Scott
> The PPT is formed with a mesh process ; leaving the checkered imprint
>on
> the surface ; supposedly keeping the flux in place .
> You still pay for the stencil ; only shift the process to bare board
>.
> The polished rollers process sounds intriguing .
> I've send a reply to this topic few moths back ; it'll be in files ,
> incl. the contacts .
> From cost , no clean , double sided application , ( you do need a
>reflow
> with chiller of bottom side ), etc. , it is impractical for most of
>the
> assy spectrum . Very limiting and complex on the mix TH & SMD as well
>.
> There are better and cheaper ways how eliminate stencil process ,
> pending the application .
>
> See you paul ; ResMed
>
> >----------
> >From: Lolmaugh, Scott (AZ15)[SMTP:[log in to unmask]]
> >Sent: Thursday, 14 May 1998 0:15
> >To: [log in to unmask]
> >Subject: Re: [TN] HASL alternatives
> >
> >All,
> >There was an interesting article in the February issue of SMT
>Magazine
> >(IHS Publishing Group) on page 56, entitled: "End Paste Defects with
> >Solid Solder Deposits". This is a technique where the PWB
>Manufacturer
> >applies solder to the board, then runs the boards through polished
> >rollers to flatten the solder coating into a flat surface roughly
>the
> >same height as the soldermask. Then a tacky flux is applied and
>finally
> >an easy peel cover sheet. They claim the boards retain
>solderability
> >well and the paste stencil process is eliminated.
> >
> >There have been similar / identical techniques touted in the past,
>known
> >as:
> >"Sipad" (R) Siemens AG, (solderpaste application method)
> >"Optipad" (R) Viele Circuits Inc. and Burkle USA, (liquid solder
> >application method) and
> >"Precision Pad Technology or PPT (R) Mask Technology Inc.
>(solderpaste
> >application w/ textured finish)
> >
> >If anyone knows of domestic (USA) Manufacturers offering this
>technology,
> >I'd like to hear who they are.
> >Thanks
> >Best Regards,
> >Scott Lolmaugh
> >SMT Production Engineering
> >Honeywell IAC, Inc.
> >602.313.3551 /FAX: 3402 (Please call first)
> >
> >
> > -----Original Message-----
> >From: [log in to unmask]
> >Sent: Wednesday, May 13, 1998 8:39 AM
> >To: [log in to unmask]
> >Subject: [TN] HASL alternatives
> >
> >To All,
> >We are now making a comparison between different alternatives to
>HASL.
> >The
> >chosen alternative will have to meet the following criterias
>criterias.
> >
> > - flat coating
> > - compatible with No-clean process and mixed technology
> > - resistant to 2-3 reflow (multiple heat cycle)
> > -and MINIMUM 1 year shelf life (storage before assembly)
> >
> >These are the alternatives we think can meet our needs:
> >
> >* OSP
> > - Benzimidazole (?)
> >
> >* IMMERSION
> > - Silver
> > - Bismuth
> > - Au-Ni
> > - Palladium
> >
> >
> >Q: Wich one do you think could be the best meet to our criterias ?
> >
> >Q: And what would be its advantage(s) compared to the others ?
> >
> >Q: OTHERS ? (is anyone using other coating alternative )
> >
> >
> >Thanks for all for your help
> >
> >
> >Nicolas van der Heyden
> >
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