Good morning Weemei - In response to your questions: 1] Yes, it is true that solder will flow thru a via, when that via is placed in a component termination pad. This results in a condition where solder is stolen from the intended termination, resulting in an insufficient solder connection. In turn, a portion of that solder fills the via, and a bead may form on the opposite side of the circuit board. This was a design technique that many of us tried in the late 1980's and discarded as a result of the problems noted above. 2] The vias we experienced this problem with were in the .012-.018" finished inner diameter range. I have not experimented to determine whether a small enough via could be created to prevent capillarity. Given the flow charactaristics of molten solder, I suspect this could not be accomplished in a manner that can be repeated consistantly under production conditions. Since proven design alternatives exist, this would seem to be an entertaining science project with little or no practical application. 3] As noted in item 2 above - I have no answer for this question. Regards - Kelly ################################################################ TechNet E-Mail Forum provided as a free service by IPC using LISTSERV 1.8c ################################################################ To subscribe/unsubscribe, send a message to [log in to unmask] with following text in the body: To subscribe: SUBSCRIBE TechNet <your full name> To unsubscribe: SIGNOFF TechNet ################################################################ Please visit IPC's web site (http://www.ipc.org) "On-Line Services" section for additional information. For technical support contact Hugo Scaramuzza at [log in to unmask] or 847-509-9700 ext.312 ################################################################