Xiangchen, a microvia can only contact to the next layer below. Inside the PCB you would need buried vias of normal size in order to connect to other layers as well. Still quite an expensive solution, only to be recommended if absolutely necessary, like e.g. with 0.5mm pitch BGAs.
Mit freundlichem Gru� Kind regards Gisbert Auge N.A.T. GmbH www.nateurope.com You wrote on 29.10.2004 10:48:43: >Jason > >Thanks. For my 4-layered board, the BGA pads must be faned out to bottom >layer by vias uder them. Can the microvia drill through the 2 planes and >bottom layer? > >Xiangchen > >----- Original Message ----- >From: "Jason Morgan" <[EMAIL PROTECTED]> >To: "Protel EDA Discussion List" <[EMAIL PROTECTED]> >Sent: Friday, October 29, 2004 5:16 PM >Subject: RE: [PEDA] put via under the BGA pad > > >> Or you can use a microvia, which is a tiny via laser drilled through just >> one layer, its so small that it won't steal any solder. Again, its costly >> compared to 'normal' process. >> >> j. >> ____________________________________________________________ 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]
