The most important is "Solder ball are entrapped/encapsulated". You ought to double check this at first and then to check the minimum electrical clearance. On minimum electrical clearance, please refer Appendix A at the end of 610D.





Best Regards,



James Liu 刘春光

Director, Technology & Standardization 技术与标准总监

IPC China

上海市长宁区延安西路1088号2303室

Suite 2303，#1088 West Yan'an Rd., Changning, Shanghai 200052 PRC

Tel:   +86 21 5497 3435

Fax:  +86 21 5497 3437

MP:   +86 136 0133 3491

[log in to unmask]

www.ipc.org.cn

________________________________________

发件人: TGAsia [[log in to unmask]] 代表 Jackson Chan [[log in to unmask]]

发送时间: 2009年12月17日 11:12

收件人: Listserv TGAsia

主题: [TGAsia] SMT reflow - microsolder ball requirement



Dear all,



Recently, I have the discussion with the customer on the specification of

solder ball especially at the region between the leads of IC.



Referring to IPC-A-610D, section 5.2.6.1



It states that “solder balls do not violate minimum electrical clearance”



It came out the question on what is “minimum electrical clearance” and "how

to relate the solder ball (in terms of size and distance) to this minimum

electrical clearance"



IPC-2221 has the minimum electrical spacing under different voltage. For

typical voltage 0 - 15V, it is 0.13mm min.   Should we use 0.13mm (minimum

electrical conductor spacing) to define minimum electrical clearance stated

in the solder ball requirement per clause 5.2.6.1 of IPC-A-610D ?



Hope IPC and experts here to elaborate the solder ball requirement here.



Regards,



Jackson