Jim, We have done a couple of 0.8mm BGA designs with 4 mil laser drilled �Via and 4 mil tracks - it all depends the capabilities of your manufacturer! Regarding the RCC thikness; keep in mind that laser drilled Vias typically will have an aspect ratio 1, no more no less! Meaning no chance to play with dielectric thikness just with the dielectric constant of the material selected. Again here: talk to your manufacturer what his capabilities are.
Hope this helps, Emanuel --- MPL AG www.mpl.ch Emanuel Zimmermann [EMAIL PROTECTED] Manager R&D Phone: +41 56 483'34'34 Taefernstrasse 20 Fax: +41 56 493'30'20 CH-5405 Daettwil --- [EMAIL PROTECTED] wrote on 26.10.2004 09:32:05: > Is anyone reliably designing and building boards using .5 mm pitch BGA's? > We're currently doing a layout using these little monsters! > > The greatest difficulty is maintaining the 60 ohm impedance required for > the SDRAM bus. To accomplish this we're finding it's necessary to use 4 mil > micro vias in 11 mil BGA pads, and to get close to 60 ohms we need 3 mil > traces on the outer layers of an RCC board. > > Are there any good alternatives to RCC that will allow us to use thicker > dielectric adjacent to the outer layers (thus wider traces) and still > maintain the 4 mil holes? Can anyone recommend a good fab house for this > kind of design? > > Thanks, > > JM > > > > ____________________________________________________________ > You are subscribed to the PEDA discussion forum > > To Post messages: > mailto:[EMAIL PROTECTED] > > Unsubscribe and Other Options: > http://techservinc.com/mailman/listinfo/peda_techservinc.com > > Browse or Search Old Archives (2001-2004): > http://www.mail-archive.com/[EMAIL PROTECTED] > > Browse or Search Current Archives (2004-Current): > http://www.mail-archive.com/[EMAIL PROTECTED] > ____________________________________________________________ You are subscribed to the PEDA discussion forum To Post messages: mailto:[EMAIL PROTECTED] Unsubscribe and Other Options: http://techservinc.com/mailman/listinfo/peda_techservinc.com Browse or Search Old Archives (2001-2004): http://www.mail-archive.com/[EMAIL PROTECTED] Browse or Search Current Archives (2004-Current): http://www.mail-archive.com/[EMAIL PROTECTED]
