TECHNET Archives

March 2012

TechNet@IPC.ORG

Options: Use Monospaced Font
Show Text Part by Default
Show All Mail Headers

Message: [<< First] [< Prev] [Next >] [Last >>]
Topic: [<< First] [< Prev] [Next >] [Last >>]
Author: [<< First] [< Prev] [Next >] [Last >>]

Print Reply
Subject:
From:
Victor Hernandez <[log in to unmask]>
Reply To:
TechNet E-Mail Forum <[log in to unmask]>, [log in to unmask]
Date:
Fri, 9 Mar 2012 12:29:44 -0600
Content-Type:
text/plain
Parts/Attachments:
text/plain (191 lines)
I always do copper integrity evaluation Pre and Post etch on all cross section sample.   The Pre is for IP separation.

Victor,

-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Paul Reid
Sent: Friday, March 09, 2012 12:18 PM
To: [log in to unmask]
Subject: Re: [TN] RE: HDI PCB - micro-via

Hi Mei and Inge,

Inge - I noticed that you referred to a report I wrote but I didn't see
a link. You are free to use anything I have published so there is no
problem. I am curious as to which report you are talking about.

Mei - I think that these microsections appear OK but...

1. The first picture is of a dielectric filled and capped microvia but
the section is not to the center of the microvia so the width
measurements may appear to be less than they are in reality. There may
be a crack between the base of the microvia and target pad. It looks
like there maybe a crack in the flash plating at the base but it is hard
to tell.
2. This appears to be a copper filled microvia with a crack in the upper
right corner. Again I don't know if the microsection is ground to the
center of the microvia.
3. This appears to be a copper filled microvia with a large microetch
into the target pad (almost through the target pad plating).
4. This appears to be a dielectric filled microvia but it is not ground
the center.
5. This is a picture of a buried via without a cap.

I personally think you should evaluate microsections after a microetch
(which has been done here).

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 Inge Hernefjord
Sent: March 9, 2012 10:52 AM
To: [log in to unmask]
Subject: Re: [TN] RE: HDI PCB - micro-via

Hi Mei,

Have you used a chain saw?  I've been investigating thousands of vias,
and
I think I'm right when I say that you can't get reliable and useful
information if you don't polish correctly. Start with grit 600 for a few
seconds, then 1200, 2500 and 4000.  Use rotating sample holders to avoid
smearing of copper. After polishing, a light dip in a copper etchant and
then DI rinse. Yeah, it's a boring job, but you will find that  the
analysis becomes more interesting. AND.....read the below report of Paul
Reid (he may see this, hope he won't accuse me for copyright
trespassing).
See the difference between the poor prepared samples and the correctly
prepared ones. Read the whole paper and you will learn LOTS!

Good Luck!

Inge




On 9 March 2012 13:25, Steve Gregory <[log in to unmask]> wrote:

> Hi Wee Mei!
>
>
>
> I have your pictures posted:
>
>
>
> http://stevezeva.homestead.com/first_microvia__1-2_.jpg
>
>
>
> http://stevezeva.homestead.com/2nd_microvia__3-4_.jpg
>
>
>
> http://stevezeva.homestead.com/microvia-1__9-10_.jpg
>
>
>
> http://stevezeva.homestead.com/microvia-2__9-10_.jpg
>
>
>
> http://stevezeva.homestead.com/buried_via.jpg
>
>
>
> Maybe some Technetters can steer you in the right direction....
>
>
>
> Steve
>
>
>
>
>
> From: Lum Wee Mei <mailto:[log in to unmask]>
>
> Sent: Thursday, March 08, 2012 7:04 PM
>
> To: Steve Gregory <mailto:[log in to unmask]>
>
> Subject: HDI PCB - micro-via
>
>
>
> Steve,
>
>
>
> I have never inspected any HDI PCBs before and was asked to perform
> inspection to them in accordance to IPC-A-600 and if necessary
IPC-6012. I
> have no idea what I am looking for as I stare at those pictures which
I
> randomly took from two of the cross-section buttons. I flipped through
the
> whole IPC-A-600 and 6012 but not able to see any images/pictures that
> correspond to what I see. Also am I suppose to use 6012 or 6016 to
assist
> in the inspection criteria? I am totally lost.
>
>
>
> Kindly post the pictures to TechNet so that some kind souls can help
me
> out of this dark tunnel. J
>
>
>
> Thanks and regards,
>
> ~wee mei~
>
>
> DSO 40th Anniversary - Celebrating 40 years of Serious Fun. 1972 -
2012
>
>
> ______________________________________________________________________
> This email has been scanned by the Symantec Email Security.cloud
service.
> For more information please contact helpdesk at x2960 or
[log in to unmask]
> ______________________________________________________________________
>

______________________________________________________________________
This email has been scanned by the Symantec Email Security.cloud
service.
For more information please contact helpdesk at x2960 or
[log in to unmask] 
______________________________________________________________________

______________________________________________________________________
This email has been scanned by the Symantec Email Security.cloud service.
For more information please contact helpdesk at x2960 or [log in to unmask] 
______________________________________________________________________

______________________________________________________________________
This email has been scanned by the Symantec Email Security.cloud service.
For more information please contact helpdesk at x2960 or [log in to unmask] 
______________________________________________________________________

ATOM RSS1 RSS2