NDLI: Board level reliability of mixed solder interconnects

Content Provider	IEEE Xplore Digital Library
Author	Sriyarunya, A. Tondtan, J. Kittidecha, W. Tukiman, H.
Copyright Year	2009
Description	Author affiliation: Spansion, (Thailand) Limited, Pakkerd, Nonthaburi, Thailand (Sriyarunya, A.; Tondtan, J.; Kittidecha, W.) \|\| Spansion (Kuala Lumpur)Sdn.Bhd (Tukiman, H.)
Abstract	While the majority of electronics has converted to lead-free materials, a portion of the industry that provides electronics for some applications, with limited availability of some tin-lead (SnPb) parts, has resulted in the potential use of lead-free (Pb-free) parts in a SnPb assembly process as mentioned as the backward assembly process. While the material supply base converts from leaded to lead-free components, there will be a combination where leaded solder paste and lead-free solders are being used in the same assembly. Maintaining solder joint reliability is one of the key challenges as the industry complies with new lead-free requirements. The primary objective of the study was to qualify the reliability of mixed assemblies by comparing them to the conventional Sn-Pb assembly process and completely Pb-free assembly process. The effect of the pure Sn plating thickness and SMT reflow profile were also investigated using a design of experiments (DOE) approach. The test vehicles were TSOP 48 and TSOP 56 with SnPb and pure tin plating finish respectively on organic solderability preservative (OSP) printed circuit board surface finish. The SnAgPb and SAC solder paste was used. Reflow profiles with peak temperature at 213 °C and 225°C were employed on backward assembly condition. The lead pull test was performed in the “as-soldered” condition. The performance of the solder joints were quantified in term of pull strength. The assemblies were subjected to thermal shock test as per Interconnecting and Packaging Electronic Circuits/Joint Electronic Device Engineering Council (IPC/JEDEC) standard at condition of −40/100 °C, 15 minutes dwell time, 1 cycle per hour and 2,000 cycle. During the test the resistance of daisy-chained solder interconnects were monitored. The performance of the TSOP solder joint was quantified in terms of the number of cycles to failure, which was analyzed by Weibull statistics. The microstructural analysis of the solder joint indicated the distribution of Lead (Pb) in the solder joint matrix and the intermetallic formation at various reflow profile condition as comparison. The results show that the mean cycle to failure of Matte Sn solder finish leadframe packages with SnAgPb (backward assembly process) and SnAgCu paste (Pb-free assembly process) were not significantly different and they were lower than those with SnPb solder finish and SnAgPb paste (conventional SnPb assembly process). For backward process, it was found that the mean cycle to failure significantly decreased when the Sn plating thickness increased.
Starting Page	249
Ending Page	253
File Size	583856
Page Count	5
File Format	PDF
ISBN	9781424450992
e-ISBN	9781424451005
DOI	10.1109/EPTC.2009.5416543
Language	English
Publisher	Institute of Electrical and Electronics Engineers, Inc. (IEEE)
Publisher Date	2009-12-09
Publisher Place	Singapore
Access Restriction	Subscribed
Rights Holder	Institute of Electrical and Electronics Engineers, Inc. (IEEE)
Subject Keyword	Lead Assembly Environmentally friendly manufacturing techniques Circuit testing Soldering Tin Integrated circuit interconnections Industrial electronics Electronic packaging thermal management Electronics industry
Content Type	Text
Resource Type	Article

Sl.	Authority	Responsibilities	Communication Details
1	Ministry of Education (GoI), Department of Higher Education	Sanctioning Authority	https://www.education.gov.in/ict-initiatives
2	Indian Institute of Technology Kharagpur	Host Institute of the Project: The host institute of the project is responsible for providing infrastructure support and hosting the project	https://www.iitkgp.ac.in
3	National Digital Library of India Office, Indian Institute of Technology Kharagpur	The administrative and infrastructural headquarters of the project	Dr. B. Sutradhar bsutra@ndl.gov.in
4	Project PI / Joint PI	Principal Investigator and Joint Principal Investigators of the project	Dr. B. Sutradhar bsutra@ndl.gov.in Prof. Saswat Chakrabarti will be added soon
5	Website/Portal (Helpdesk)	Queries regarding NDLI and its services	support@ndl.gov.in
6	Contents and Copyright Issues	Queries related to content curation and copyright issues	content@ndl.gov.in
7	National Digital Library of India Club (NDLI Club)	Queries related to NDLI Club formation, support, user awareness program, seminar/symposium, collaboration, social media, promotion, and outreach	clubsupport@ndl.gov.in
8	Digital Preservation Centre (DPC)	Assistance with digitizing and archiving copyright-free printed books	dpc@ndl.gov.in
9	IDR Setup or Support	Queries related to establishment and support of Institutional Digital Repository (IDR) and IDR workshops	idr@ndl.gov.in