Eileen - The recommendations I received from my fabricator are as follows: 0.013 dia. BGA lands 0.0195 dia. Via lands 0.010 dia. Via drill (through) All connections to be tear-dropped (filleted) This will allow for a 5 mil trace and space routing on external layers and 4 mil traces with 5 mil spaces on internal layers. Good luck with the design. Jeffrey A. McGlaughlin Sr. PCB Designer Battelle Memorial Institute Columbus Ohio [log in to unmask] -----Original Message----- From: Eileen Ong [R&D] [SMTP:[log in to unmask]] Sent: Tuesday, 14 March, 2000 05:23 To: [log in to unmask] Subject: [DC] BGA Hi, This is the first time using a micro BGA package (256 lead,pitch 1mm) below are some of my questions that anyone help me. 1) What pad size to use for a good solder joint? 2) What is the best way to route and layers needed? Also the most cost saving example microvia,blind/burried via ? 3) what trace width to use ? 4) Is it possible to route this BGA without using any via on pads ? 5) What are the instruction for pcb manufacturer. 6) Any one who have design this type of bga that can share your package or show me your design. ( I'm a Pads user) Tia. Best Regards, EILEEN ONG (R&D Dept.) Paradise Innovations (Asia) Pte Ltd 25 Serangoon North Ave 5 6th floor Uraco Building Singapore 554914 Did: (65) 485-6690 (Office) Fax: (65) 481-2611 Email : mailto:[log in to unmask] Web: http://www.paradisemmp.com