[PCB_FORUM] Re: 0.5 mm BGA, whew!

  • From: "Hugh Allen" <hugh@xxxxxxxxxxxxx>
  • To: <icu-pcb-forum@xxxxxxxxxxxxx>
  • Date: Tue, 2 Nov 2004 14:55:43 -0500

Message Perhaps there is a reason that  the acronym list is missing some
significant ones:

    CC   caused by ASS

   "communication constipation"   caused by "alphabet soup stoppage".

 Then there is the game  1U   played using   IKSYD  na na   na na

   "one up-person-ship"  played using " I know something you don't"  na na
na na.


Hugh Allen
Specctra Specialist
CopperCad Design
www.coppercad.com
hugh@xxxxxxxxxxxxx

  -----Original Message-----
  From: george.h.patrick@xxxxxxxxxxxxxx
[mailto:george.h.patrick@xxxxxxxxxxxxxx]
  Sent: Tuesday, November 02, 2004 2:06 PM
  To: icu-pcb-forum@xxxxxxxxxxxxx
  Subject: [PCB_FORUM] Re: 0.5 mm BGA, whew!



  Or Laughing Out Loud.  A little more energetic is ROFL (Rolling On the
Floor Laughing).  A little more manic is ROFLMAO (Rolling On the Floor
Laughing My A__ Off).

  IIRC (If I Remember Correctly)

  Lots of these abbreviation thingies were used as TTY shortcuts when I was
in the Navy in the seventies :)

  Also, check out http://www.acronymfinder.com/

  CUL
  --
  George Patrick
  Tektronix, Inc.
  Central Engineering, PCB Design Group
  P.O. Box 500, M/S 39-512
  Beaverton, OR 97077-0001
  Phone: 503-627-5272         Fax: 503-627-5587
  http://www.tektronix.com    http://www.pcb-designer.com

  It's my opinion, not Tektronix'

    -----Original Message-----
    From: Degennaro, Natalie N [mailto:natalie.n.degennaro@xxxxxxxxx]
    Sent: Tuesday, November 02, 2004 10:47
    To: icu-pcb-forum@xxxxxxxxxxxxx
    Subject: [PCB_FORUM] Re: 0.5 mm BGA, whew!


    My Instant messager Husband says it means Lots of Laughs. He he he. ;-)




----------------------------------------------------------------------------

    From: Tom Robinson [mailto:trobinson@xxxxxxxxxx]
    Sent: Tuesday, November 02, 2004 10:46 AM
    To: icu-pcb-forum@xxxxxxxxxxxxx
    Subject: [PCB_FORUM] Re: 0.5 mm BGA, whew!



    Hi Natalie:



    What is "LOL" ?



    tr :)



      -----Original Message-----
      From: Degennaro, Natalie N [mailto:natalie.n.degennaro@xxxxxxxxx]
      Sent: Friday, October 29, 2004 12:59 PM
      To: icu-pcb-forum@xxxxxxxxxxxxx
      Subject: [PCB_FORUM] Re: 0.5 mm BGA, whew!

      Gary,



      1)       We use micro vias in pad (built into padstack used, and are
through hole).

      2)       Decide ahead of time and build them into the symbol.
Otherwise "replace padstack" for when you do know what layers you need to
connect to. That will get you out of the DRC quandary. You can use the
blind/buried via wizard to generate them automatically.

      3)       Why are you still using a .brd in mils? Your parts are
dictating that you need to switch to millimeters (like we have). Or is this
just a personal thing? (LOL). Parts built in millimeters and then read into
a mils .brd will have round off.

      4)       Why do this?

      5)       Why not have a micro via in pad set for 1-4, in your example?
Your three mv's are going to connect anyway, if they are at same center.



      It doesn't have to be as hard as you think. Just change the way you
think and try something new (LOL). It can be fun!



      Natalie




--------------------------------------------------------------------------

      From: Gary MacIndoe [mailto:gary.macindoe@xxxxxxx]
      Sent: Friday, October 29, 2004 9:06 AM
      To: Allegro Forum
      Subject: [PCB_FORUM] 0.5 mm BGA, whew!



      All,



      Well, it seems to be a slow day on the Forum, so I'll through out a
relatively involved set of questions!



      We are looking into using a 0.5 mm BGA in a very dense design, so big
time HDI practices will come into play: micro vias (MVs), probably even
stacked micro vias (SMVs), in order to fan out on several layers.



      -  would you use the micro vias in pad or not?  Why?  Build them into
the symbol?



      -  how can you have the micro vias built into the symbol if you don't
know which balls will go down to which layer?



      -  I will make the 0.5 mm BGA Allegro symbol with the drawing units
set to Millimeters, but would like to keep the design database set to Mils.
Is this the way most of you have done it?



      -  if the symbol is set to Millimeters and the design set to Mils,
this makes dropping the micro vias (in pad or not) after the BGA symbol is
placed in the design tricky.  Any other way to get around this?



      -  So, setting up blind/buried micro vias should be the same as any
blind/buried via.  How about SMVs?  If you have a micro via set up for
layers 1-2, 2-3, 3-4, etc., how do you avoid the DRCs when you stack them
(same X,Y)?



      My head is about spinning trying to comprehend all of this micro
via/stacked micro via stuff!



      Any help from someone that has already used a 0.5 mm BGA on a very
dense design with stacked micro vias would be greatly appreciated!!



      Thanks in advance,

      Gary E. MacIndoe
      PCB Design Engineer
      Advanced Micro Devices, Inc.
      Longmont, Colorado



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