Here is the abstract you requested from the dpc_2018 technical program page. This is the original abstract submitted by the author. Any changes to the technical content of the final manuscript published by IMAPS or the presentation that is given during the event is done by the author, not IMAPS.
|High Precision Uniquely Designed De-flux Cleaning Solution for Advanced Packaging|
|Keywords: High Precision Cleaning , deflux, PCB, substrate, flip chip|
|The advancement of the electronics industry demands for electronic circuits to become denser and more integrated in order to achieve higher frequencies and speeds. With the miniaturization of electronic parts, the clearances between components are becoming tighter. Besides that, the transition to CFC-free and lead-free in the field of electronic packaging technology has put pressure on the electronics cleaning technology as flux becomes more difficult to clean with lead-free soldering due to the higher temperatures used during the soldering process. This causes the flux residue to become more difficult to remove. These higher temperatures and tighter clearances have made deflux cleaning of electronics more necessary and challenging. The cleanliness requirements for electronic components and assemblies have increased over the past few years. With functional quality being directly associated to the presence of foreign matter, even the most minute particle contaminants are able to result in the failure of a component which could potentially cause the subsequent failure of the machinery. To meet this demand, Cactus Materials, Inc. and Kaken Tech Co., ltd studied glycol ether based chemicals for PCBs flux cleaning using COMB shaped structures and with SMT. In this article, we presented results of our case studies and specifically define the chemicals for cleaning of flux residue on PCBs after soldering, which requires the most sophisticated cleaning technology of all, as “de-flux chemicals.” Flux comprises of polar and non-polar compounds and cleaning solutions can be targeted for both these compounds. Based on our experiments, this uniquely designed solution resolves wide range of solubility i.e. high rinse performance compare to fluorides and carbon hydrides. Studies incorporated only lead-free solder paste on SMT components. We also studied di-electric loss at high humidity for glycol based solution and semi-aqueous solutions, it is found that capacitance dissipation factors on frequency (10kHz to 1 mHz) varies on aqueous solutions whereas no changes on glycol based solution. This is critical factors while at BHAST applied to PCB or substrates. This property of the glycol based solutions helps to increase yield and ensure no escapee to customers. In addition, this solution demonstrates quick dry (dry 4x faster) compare to aqueous (water based) based solutions and comparable to IPA. The surface insulation resistance (Ohm) stays similar after prolonged time 1000 hrs (250C, 94% RH) and temperature cycle of 700C (20 mins) to 250C (10 min) at 54% RH, 250C. Further characterization to be performed at Cactus Materials, Inc. lab at ASU research park center.|
|Ajit Dhamdhere, PhD, Engineering Lead
Cactus Materials, Inc.