Manufacturing requested something similar for the large pad of our D2PAK footprint. The paste stencil has 3 rectangular openings, sized to deposit paste on about 70% of the pad. They requested this because a full stencil opening was causing some sort of problem with excess solderpaste. Possibly solderballs. Sorry I can't remember what the exact problem was. Normally I try to learn the "why" of things when Manufacturing makes that kind of request, but it has been a few years. If your "sketch" below is close to scale, that seems like a very small amount of paste. I will echo what is often suggested on this list: you should run it past your assembly people. Ron -----Original Message----- From: ert ert [mailto:[log in to unmask] <mailto:[log in to unmask]> ] Sent: Wednesday, July 12, 2006 12:24 AM Subject: OFN thermal pad pastemask Hi All, I recently captured on a board, the QFN package has thermal pad whose paste mask is not fully opened but has small square openings as shown below. What the reason to provide this type of pastemask? _____________________ | ___ ____ | | | | | | | | | | | | | | ------ ------ | | | | ___ ____ | | | | | | | | | | | | | | ------ ------ | | | ------------------------------------- Thanks, Nagaraj C.I.D --------------------------------------------------------------------------------- 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 temporarily stop/(restart) delivery of DesignerCouncil send: SET DesignerCouncil NOMAIL/(MAIL) 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 847-615-7100 ext.2815 ---------------------------------------------------------------------------------