Tom, I worked in various design areas for a fairly large company (IBM). The last several were spent working on TBGA designs and they all used via in pad for the array. All assembly/test was done in house and once the process and design parameters were defined there were no problems related to that design feature. After about 10 years this entire line/process was sold off to become a separate business and they still continued to produce TBGA products with via in pad designs. I believe our original via size was 0.008" and was eventually reduced to 0.002". I'm sure there were a few "patented" processes and tools involved. This was being done from the mid 90's until 2002 and we shipped a lot of parts (probably millions) to both internal and external customers during that time frame and the general design and build process remained fairly constant. Scott D. Riley Technical Design Service 607-658-9322 - Office 607-785-1696 - FAX www.techdesignservice.com -----Original Message----- From: DesignerCouncil [mailto:[log in to unmask]] On Behalf Of Tom Parkinson Sent: Friday, June 25, 2004 11:14 AM To: [log in to unmask] Subject: [DC] VIA in Pad We're a CM. One of our customers is asking us to build a board assembly that will be using BGAs with VIAs in pads. They are in the design stages at this point, and we have some concerns with having a Via in the middle of a BGA pad. Anyone have suggestions and/or experience with this?? Thanks Tom Parkinson - Quality System Manager - CIT WinTronics, Inc. Ph: 724-981-5770 Ext. 235 Fax: 724-981-1772 ---------------------------------------------------------------------------- ----- DesignerCouncil Mail List provided as a free service by IPC using LISTSERV 1.8d To unsubscribe, send a message to [log in to unmask] with following text in the BODY (NOT the subject field): SIGNOFF DesignerCouncil. To set a vacation stop for delivery of DesignerCouncil send: SET DesignerCouncil NOMAIL Search previous postings at: www.ipc.org > On-Line Resources & Databases > E-mail Archives Please visit IPC web site http://www.ipc.org/contentpage.asp?Pageid=4.3.16 for additional information, or contact Keach Sasamori at [log in to unmask] or 847-509-9700 ext.5315 ---------------------------------------------------------------------------- ----- --------------------------------------------------------------------------------- DesignerCouncil Mail List provided as a free service by IPC using LISTSERV 1.8d To unsubscribe, send a message to [log in to unmask] with following text in the BODY (NOT the subject field): SIGNOFF DesignerCouncil. To set a vacation stop for delivery of DesignerCouncil send: SET DesignerCouncil NOMAIL Search previous postings at: www.ipc.org > On-Line Resources & Databases > E-mail Archives Please visit IPC web site http://www.ipc.org/contentpage.asp?Pageid=4.3.16 for additional information, or contact Keach Sasamori at [log in to unmask] or 847-509-9700 ext.5315 ---------------------------------------------------------------------------------