Conducive Adhesive as a Lead Free Solution
Lead containing solder pastes have used for the connection of electronic components to PCBs for many years. Due to the increase in public ecological awareness in combination with the legislations (RoHS & WEEE) manufacturers of electronic devices are looking for alternative materials to replace the lead.The popular alternative is the SnAgCu alloy which has a significantly higher melting point compared to tin/lead solders. Different lead-free solder materials were found with low temperature metal alloys but several reliability and workability issues are still not fully addressed. For this reason there is a growing interest in conductive adhesives as an alternative to lead-free solders.An electrically-conductive adhesive (CA) consists of a polymer and conductive filler. The polymer allows for proper adhesion, the filler provides the conductivity. It is shown that, in certain conditions, CA can be used in place of solders with standard SMT equipment and can even offer certain advantages. Some of these advantages are: lower processing temperature, fine pitch printing capability and a higher flexibility of the cured polymer in comparison to solder. For these reasons the CA is a suitable and a user-friendly solution for temperature sensitive applications like LED-attach on flexible substrate and temperature-sensitive substrates.Like solder, CA can have some drawbacks. Generally the conductivity for CA Is lower than that of solder for example. CA is also not compatible with every PCB finish under harsh conditions. Heraeus has done some investigations to find out the pros and cons of CA in relation to lead-free solder. The main focus of this study was on the reliability of the connections with CA. These tests show promising results.
Conductive Adhesive (CA),Die Attach RoHS Lead Free Silver filled PCB
Alexander Brand Thomas Krebs Hans-Werner Hagedorn
W.C Heraeus GmbH Heraeusstrasse 12-14 63450 Hanau, Germany
国际会议
Chinas Premier SMT & MPT Event(2007年中国国际表面贴装和微组装技术大会)
上海
英文
23-36
2007-03-22（万方平台首次上网日期，不代表论文的发表时间）