Barbara,
A Via pad is required in the center of every 4 pads.
The diagonal space between 2 bga pads with .25 mm dia. leaves 0.67 mm.
Minimum via pad dia. - see also Dwight response- would be .46 mm
leaving 0.1 mm (4 mils) via2bgapad distance.
This can be done - but highly not recommended . With Inner via pad the
same size you get 7.5 mils between 2 adjacent via pads - enough for 1
trace 3 mils wide only.You should calculate the escapes for all your
signals + plane layers to find how many layers you'll need.
I suggest you search the Amkor web site they have good design
application notes.
Mickey
_____
From: Barbara Burcham [mailto:[log in to unmask]]
Sent: Monday, August 03, 2009 7:17 PM
To: weiner, mickey
Subject: Re: [TN] Looking for a fabricator for a .65mm bga brd
Hi Mickey,
The matrix is full. Pad size recommended is .3mm and am considering a
.25mm pad...the balls on the part are collapsible so that makes me a
smidge nervous. Should I be?
Thanks for any suggestions,
Barbara
On Mon, Aug 3, 2009 at 10:05 AM, weiner, mickey
<[log in to unmask]> wrote:
Barbara,
Is 0.65 mm the pitch? Is it a full matrix ? what's the
recommended
pad size
I doubt if under 0.8 mm pitch you'll manage without blind vias
Mickey r
-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Barbara
Burcham
Sent: Monday, August 03, 2009 5:23 PM
To: [log in to unmask]
Subject: [TN] Looking for a fabricator for a .65mm bga brd
I am working on a layout that has a 0.65mm 14x14 matrix bga on
an 0.062
thick board. I have to be able to place through hole vias
between the
pads.
Would love to use 3 and 3 spacing.
Who out there can advise me about this?
Yes, the board HAS to be 0.062 thk...has a card edge
connector...but can
be on the low side of that.
Yes, we really want to use through hole vias.
We can use 1/2 oz copper on all 8 layers.
The board is small and can easily be run on a smaller production
panel
to improve tolerances.
So, how small a capture pad and hole can be done in a production
environment, reliably?
Need to get this nailed down today.
Barbara Burcham, C.I.D.
pcb Trace Design
281-341-7539 Wk/Hm
713-249-7718 Cell
[log in to unmask]
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pcb Trace Design
281-341-7539 Wk/Hm
713-249-7718 Cell
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This e-mail message and any attachments thereto, is intended only for use by the addressee(s) named herein and may contain legally privileged and/or confidential information. If you are not the intended recipient of this e-mail message, you are hereby notified that any dissemination, distribution or copying of this e-mail message, and any attachments thereto, is strictly prohibited. If you have received this e-mail message in error, please immediately notify the sender and permanently delete the original and any copies of this email and any prints thereof.
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