Back to IPC technet for more comments:
1.How many are using immersion gold with barrier under-plating as
process. What is process spec for finish as immersion gold--I mean
barrier plating and gold coating.
2. If there is a board manufacturer(s), what is trend or percentage of
users on gold immersion?
3. Anybody like to share the good or bad experience on technet. Can you
recommend any board manu with good experience on large volume, long time
troublefree supply of immersion gold finish.
4. What is advise on electroless vs eletrolytic or anything else wrt
phosphorus??
5. What are the things I should check while going in for it.

I will appreciate if more no. of people comeout with responses sooner
than my next review meeting scheduled next Monday.

Here is my case rephrased for clarity:

> I am finding myself in a trapped position (suffocation) and
> desperately looking for help(oxygen). I posted a message on
> IPC-Technet and got very few replies. Some were positive and few
> others were in negatives.I am looking for somebody to advise on this.
> Here is my situation in brief:
>
> I am having trouble in using HASL finish on 16 mil FPDs. Board vendor
> is not able to maintain quality on coplanarity.That has caused stencil
> printing problems besides placement errors especially on glue mounted
> 0603 components on solder side of board.I am looking for alternaive to
> HASL:
>
> I have very limited experience on OSP and Gold immersion.I tend not to
> try OSP becuse of customer reservation on OSP. Now, for me to try out
> gold immersion, I am in a fix : what to specify and whether I am
> landing onto correct platform or not?
>
> Based on IPC-2221 , I came to spec as:
>
> Ni(electroless) barrier plating as : 150 microinches
> Immersion gold as: 4-5 microinches
>
> Per ipc-2221 spec window is : Ni electroless 100-200 microinches , min
> 52 microinches
>                               Immersion gold 3.2 to 9 microinches ,
> max 32 microinches
>
>
> Now I came across that Electroless plating used phosphorus and can
> affect the joint.Some people on SMTnet advised to use electrolytic Ni
> instead of electroless Ni.
>
> I am confused  right in the beginning. Is it a new process not used in
> large scale?
>  How I specify the immersion gold process.I am sure you can help me to
> put your piece of advice.
>
>
>
>
> Ashok Dhawan P.ENG.
> Manufacturing Engineering
> Unisys Canada Inc.
> 51 Burmac Road
> Winnipeg R2J4C9
> CANADA
> Fone 204-257-9199
> Fax   204-257-9104
>
>
>
>
>
>

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