Porosity in collapsible Ball Grid Array solder joints

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Description

Ball Grid Array (BGA) technology has taken off in recent years due to the increased need for high interconnect density. Opposite to all the advantages BGA packages offer, porosity in collapsible BGA solder joints is often a major concern in the reliability of such packages. The effect of pores on the strength of collapsible BGA solder-joints was studied by manufacturing samples with different degrees of porosity and testing them under a shear load. It was found that the shear strength of the solder joints decreased in a linear fashion with increasing porosity. Failure occurred by internal necking of the interpore ... continued below

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6963 p.

Creation Information

Gonzalez, C.A. May 1, 1998.

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This report is part of the collection entitled: Office of Scientific & Technical Information Technical Reports and was provided by UNT Libraries Government Documents Department to Digital Library, a digital repository hosted by the UNT Libraries. More information about this report can be viewed below.

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  • Gonzalez, C.A. Univ. of California, Berkeley, CA (United States). Dept. of Materials Science and Mineral Engineering

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Description

Ball Grid Array (BGA) technology has taken off in recent years due to the increased need for high interconnect density. Opposite to all the advantages BGA packages offer, porosity in collapsible BGA solder joints is often a major concern in the reliability of such packages. The effect of pores on the strength of collapsible BGA solder-joints was studied by manufacturing samples with different degrees of porosity and testing them under a shear load. It was found that the shear strength of the solder joints decreased in a linear fashion with increasing porosity. Failure occurred by internal necking of the interpore matrix. It was confirmed that entrapment of flux residues leads to porosity by manufacturing fluxless samples in a specially made furnace, and comparing them with samples assembled using flux. Also, contamination of Au electrodeposits (in substrate metallization) was determined to cause significant porosity. It was found that hard-Au (Co hardened Au) electrodeposits produce high degrees of porosity even in the absence of flux. Finally, increasing the time the solder spends in the molten state was proven to successfully decrease porosity.

Physical Description

6963 p.

Notes

OSTI as DE98059380

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  • Other Information: TH: Thesis (M.S.)

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  • Other: DE98059380
  • Report No.: LBNL--42052
  • Grant Number: AC03-76SF00098
  • DOI: 10.2172/663270 | External Link
  • Office of Scientific & Technical Information Report Number: 663270
  • Archival Resource Key: ark:/67531/metadc707572

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Office of Scientific & Technical Information Technical Reports

Reports, articles and other documents harvested from the Office of Scientific and Technical Information.

Office of Scientific and Technical Information (OSTI) is the Department of Energy (DOE) office that collects, preserves, and disseminates DOE-sponsored research and development (R&D) results that are the outcomes of R&D projects or other funded activities at DOE labs and facilities nationwide and grantees at universities and other institutions.

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Creation Date

  • May 1, 1998

Added to The UNT Digital Library

  • Sept. 12, 2015, 6:31 a.m.

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  • Nov. 6, 2015, 1:12 p.m.

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Gonzalez, C.A. Porosity in collapsible Ball Grid Array solder joints, report, May 1, 1998; United States. (digital.library.unt.edu/ark:/67531/metadc707572/: accessed December 14, 2017), University of North Texas Libraries, Digital Library, digital.library.unt.edu; crediting UNT Libraries Government Documents Department.