Especially if they're plastic-bodied BGA's, YES, unused components from a package should be resealed with desiccant. The problem is not so much oxidisation but atmospheric moisture absorbtion. This can happen within a matter of hours depending on the RH of the atmosphere they're exposed to and their sensitivity to moisture absorbtion (see reply to me earlier from Francois). If too much moisture is absorbed and not baked out again, the soldering temperatures cause the moisture to vapourise. This leads to internal weakening or physical damage to the insides of the devices, and even delamination or explosion of the casing - a phenomenon known as 'popcorning'. JEDEC J-STD-033 tells you what you need to know in this respect and is downloadable free from the Net. Pete Duncan Rick Howieson <RHowieson@DELTAGRO To: [log in to unmask] UPINC.COM> cc: (bcc: DUNCAN Peter/Asst Prin Engr/ST Aero/ST Group) Sent by: TechNet Subject: [TN] BGA <[log in to unmask]> 05/24/01 10:35 PM Please respond to "TechNet E-Mail Forum."; Please respond to Rick Howieson Need information on protecting BGA's not loaded. Should BGA's from a package not used be sealed for the next run? If so, is this because the balls become oxidized or ...? Thanks, Rick Howieson Delta Group Electronics, Inc. --------------------------------------------------------------------------------- Technet 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 Technet To temporarily halt delivery of Technet send the following message: SET Technet NOMAIL Search previous postings at: www.ipc.org > On-Line Resources & Databases > E-mail Archives Please visit IPC web site (http://www.ipc.org/html/forum.htm) for additional information, or contact Keach Sasamori at [log in to unmask] or 847-509-9700 ext.5315 --------------------------------------------------------------------------------- --------------------------------------------------------------------------------- Technet 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 Technet To temporarily halt delivery of Technet send the following message: SET Technet NOMAIL Search previous postings at: www.ipc.org > On-Line Resources & Databases > E-mail Archives Please visit IPC web site (http://www.ipc.org/html/forum.htm) for additional information, or contact Keach Sasamori at [log in to unmask] or 847-509-9700 ext.5315 ---------------------------------------------------------------------------------