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dc.contributor.authorWong, C. P.
dc.contributor.authorZhang, Zhuqing
dc.date.accessioned2006-07-07T20:11:09Z
dc.date.available2006-07-07T20:11:09Z
dc.date.issued2002-04
dc.identifier.citationIEEE Transactions on Electronics Packaging Manufacturing, Vol. 25, no. 2, April 2002, 113-119en
dc.identifier.urihttp://hdl.handle.net/1853/10763
dc.description©2002 IEEE. Personal use of this material is permitted. However, permission to reprint/republish this material for advertising or promotional purposes or for creating new collective works for resale or distribution to servers or lists, or to reuse any copyrighted component of this work in other works must be obtained from the IEEE. This material is presented to ensure timely dissemination of scholarly and technical work. Copyright and all rights therein are retained by authors or by other copyright holders. All persons copying this information are expected to adhere to the terms and constraints invoked by each author's copyright. In most cases, these works may not be reposted without the explicit permission of the copyright holder.en
dc.description.abstractLead-free solder reflow process has presented challenges to no-flow underfill material and assembly. The currently available no-flow underfill materials are mainly designed for eutectic Sn–Pb solders. This paper presents the assembly of lead-free bumped flip-chip with developed no-flow underfill materials. Epoxy resin/HMPA/metal AcAc/Flux G system is developed as no-flow underfills for Sn/Ag/Cu alloy bumped flip-chips. The solder wetting test is conducted to demonstrate the fluxing capability of the underfills for lead-free solders. A 100% solder joint yield has been achieved using Sn/Ag/Cu bumped flip-chips in a no-flow process. A scanning acoustic microscope is used to observe the underfill voiding. The out-gassing of HMPA at high curing temperatures causes severe voiding inside the package. A differential scanning calorimeter (DSC) is used to study the curing degree of the underfill after reflow with or without post-cure. The post-curing profiles indicate that the out-gassing of HMPA would destroy the stoichiometric balance between the epoxy and hardener, and result in a need for high temperature post-cure. The material properties of the underfills are characterized and the influence of underfill out-gassing on the assembly and material properties is investigated. The impact of lead-free reflow on the material design and process conditions of no-flow underfill is discussed.en
dc.format.extent272158 bytes
dc.format.mimetypeapplication/pdf
dc.language.isoen_USen
dc.publisherGeorgia Institute of Technologyen
dc.subjectFlip-chip devicesen
dc.subjectLead-free solderen
dc.subjectMaterial propertiesen
dc.subjectNo-flow underfillen
dc.subjectSolder joint yielden
dc.subjectUnderfill out-gassingen
dc.titleAssembly of Lead-free Bumped Flip-Chip with No-Flow Underfillsen
dc.typeArticleen
dc.publisher.originalInstitute of Electrical and Electronics Engineers, Inc., New York


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