Hi Mickey,

On occasion heavy plating can cause a tendency for interconnect
separation in HDI applications. The barrel of the hole becomes so strong
and rigid that it does not flex during thermal excursions associated
with assembly. This rigidness causes more stress to the outer layer,
layers 2/3 and N-1/N-2, internal interconnections. If the
interconnections are weak then you can get a separation. 

This is rare but it can occur.

We have found that .0012" is the ideal thickness. More or less than
.0012" is a reliability liability.

Sincerely,  

Paul Reid 
Program Coordinator  

PWB Interconnect Solutions Inc. 
235 Stafford Rd., West, Unit 103 
Nepean, Ontario Canada, K2H 9C1 

613 596 4244 ext. 229  

Skype paul_reid_pwb 
[log in to unmask] 

 


-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Mickey Weiner
Sent: March 1, 2012 9:00 AM
To: [log in to unmask]
Subject: Re: [TN] Excessive Copper Plating

Does it cause any assembly issues? or reduce the board reliability?

Best Regards
Mickey Weiner
972-8-9774808



On Thu, Mar 1, 2012 at 1:54 PM, William Noel <[log in to unmask]>
wrote:

> Hello all - We call out a minimum of .001 inches of copper plating on
the
> walls of our holes in our standard fabrication notes.  We don't
mention any
> min or max on exposed lands and lines. We recently received a board
that
> upon cross-section analysis we discovered it had an additional .005
inches
> of copper plated up on the top and bottom of the board.  We are
considering
> listing a maximum in our drawing notes as follows:  "PLATING PROCESS
SHALL
> NOT PRODUCE MORE THAN AN ADDITIONAL .0025 INCHES OF COPPER ON EXPOSED
LANDS
> AND LINES."  Anyone have any comments or suggestions for us?  Thanks
in
> advance.
>

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