Sam, Westwood Nanya used to have a huge repository of HDI information when Happy Holden was the chief technical contact. I believe the articles are still accessible under brochures (you'll need to register): http://www.westwoodpcb.com/1_home_3_buttons.htm Dave > > From: sjchar3@xxxxxxxxxxxx > Date: 2006/10/30 Mon AM 09:23:18 CST > To: icu-pcb-forum@xxxxxxxxxxxxx > Subject: [PCB_FORUM] Re: .4 mm pitch bga's > > We usually call the board house and ask them if they can do it. The smallest > we've gone is .5mm pad with .3 mm drill. The BGA was a 7x7 array but the ic > used only the two outside rows. We used via in pad, now I need to write up a > paper on how i did the board. Anyone seen good documentation on this subject > (BGAs, Microvias)? > > Thanks Sam > > > -----Original Message----- > From: rmora@xxxxxxxxxxxxxxxxxxxx > To: icu-pcb-forum@xxxxxxxxxxxxx > Sent: Fri, 27 Oct 2006 9:39 AM > Subject: [PCB_FORUM] Re: .4 mm pitch bga's > > > Gino, > Wow, where will it end. > We use a .25mm pad with a .1mm hole and that's pushing it. But our application > is a high volume product. > What is the BGA pad size you are using? > Are you using stacked vias? > Are the BGA pads masked defined or etch defined. > These will all have an impact on the via pad, trace space numbers. > Are you under filling the BGA? > > For the very dense designs we use ALIVH technology in an 8 layer stack up. > This allows us to put a via in pad and route directly down to any layer. > > Ron > > At 10:06 AM 10/27/2006 -0500, you wrote: > > Everyone, > > What's your recommendation for microvia sizes, line and spacing for routing > .4mm bga's? > > I saw a technotes using .065mm line and space between 0.2mm pad/0.1 drill > micro via. Anyone using these in their designs? > > regards, > Gino > ________________________________________________________________________ > Check Out the new free AIM(R) Mail -- 2 GB of storage and industry-leading > spam and email virus protection. > > ----------------------------------------------------------- To subscribe/unsubscribe: Send a message to icu-pcb-forum-request@xxxxxxxxxxxxx with a subject of subscribe or unsubscribe To view the archives of this list go to //www.freelists.org/archives/icu-pcb-forum/ Problems or Questions: Send an email to icu-pcb-forum-admins@xxxxxxxxxxxxx -----------------------------------------------------------