Please wait, while we are loading the content...
Please wait, while we are loading the content...
Content Provider | IEEE Xplore Digital Library |
---|---|
Author | Yoon-Chul Sohn Jin Yu Kang, S.K. Da-Yuan Shih Taek-Yeong Lee |
Copyright Year | 2004 |
Description | Author affiliation: Dept. of Mater. Sci. Eng., KAIST, Daejeon, South Korea (Yoon-Chul Sohn; Jin Yu) |
Abstract | Electroless Ni-P has been widely used for under bump metallization (UBM) of flip chip and surface finish layer in microelectronics packaging because of its excellent solderability, corrosion resistance, uniformity, selective deposition without photolithography, and also good diffusion barrier. However, the brittle fracture of solder joints and the spalling of intermetallic compound (IMC) associated with electroless Ni-P are critical issues for its successful applications. The mechanisms of the brittle fracture have been extensively investigated, but not fully understood yet. On the contrary, the spalling phenomenon has not been studied in detail, though IMC spalling could weaken the interfacial adhesion and also cause dewetting of flip chip solder bumps. In this study, IMC spalling from an electroless Ni-P film was investigated with lead-free solders in terms of solder deposition methods (electroplating vs solder paste), P content in Ni-P layer (4.6, 9, and 13 wt.% P), and solder thickness (120 vs. 200 /spl mu/m). The reaction of Ni-P with Sn3.5Ag paste easily led to IMC spalling after 2 min reflow at 250/spl deg/C while IMCs adhered to the Ni-P layer after 10 min reflow for the reaction with electroplated Sn or Sn3.5Ag. It has shown that both solder composition and deposition method are important for IMC spalling from a Ni-P layer. The spalling increased with P content in a Ni-P layer as well as with solder volume. Ni/sub 3/Sn/sub 4/ intermetallics formed as a needle-shaped morphology in the early stage and changed into a chunky shape. Needle-shaped compounds exhibited a higher propensity for spalling from a Ni-P layer than chunky shaped compounds because molten solder can easily penetrate into the interface between needle-shaped IMCs and the P-rich layer. A reaction between the penetrated Sn and the P-rich layer formed a NiSnP layer. The poor adhesion between the Ni/sub 3/Sn/sub 4/ compound and the NiSnP layer caused the IMC spalling. Dewetting of solder from the NiSnP layer, however, didn't occur even after spalling of most IMCs. The wetting reactions of Pb-free solders on electroless Ni-P layers are also discussed. |
Starting Page | 75 |
Ending Page | 81 |
File Size | 925617 |
Page Count | 7 |
File Format | |
ISBN | 0780383656 |
DOI | 10.1109/ECTC.2004.1319318 |
Language | English |
Publisher | Institute of Electrical and Electronics Engineers, Inc. (IEEE) |
Publisher Date | 2004-06-04 |
Publisher Place | USA |
Access Restriction | Subscribed |
Rights Holder | Institute of Electrical and Electronics Engineers, Inc. (IEEE) |
Subject Keyword | Intermetallic Metallization Environmentally friendly manufacturing techniques Lead Tin Flip chip Surface resistance Adhesives Surface cracks Surface finishing |
Content Type | Text |
Resource Type | Article |
National Digital Library of India (NDLI) is a virtual repository of learning resources which is not just a repository with search/browse facilities but provides a host of services for the learner community. It is sponsored and mentored by Ministry of Education, Government of India, through its National Mission on Education through Information and Communication Technology (NMEICT). Filtered and federated searching is employed to facilitate focused searching so that learners can find the right resource with least effort and in minimum time. NDLI provides user group-specific services such as Examination Preparatory for School and College students and job aspirants. Services for Researchers and general learners are also provided. NDLI is designed to hold content of any language and provides interface support for 10 most widely used Indian languages. It is built to provide support for all academic levels including researchers and life-long learners, all disciplines, all popular forms of access devices and differently-abled learners. It is designed to enable people to learn and prepare from best practices from all over the world and to facilitate researchers to perform inter-linked exploration from multiple sources. It is developed, operated and maintained from Indian Institute of Technology Kharagpur.
Learn more about this project from here.
NDLI is a conglomeration of freely available or institutionally contributed or donated or publisher managed contents. Almost all these contents are hosted and accessed from respective sources. The responsibility for authenticity, relevance, completeness, accuracy, reliability and suitability of these contents rests with the respective organization and NDLI has no responsibility or liability for these. Every effort is made to keep the NDLI portal up and running smoothly unless there are some unavoidable technical issues.
Ministry of Education, through its National Mission on Education through Information and Communication Technology (NMEICT), has sponsored and funded the National Digital Library of India (NDLI) project.
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 |
Loading...
|