Measurement of water absorption in ball grid array package

Ken Oota, Hiroshi Iida, Masumi Saka

Research output: Contribution to journalArticlepeer-review

1 Citation (Scopus)

Abstract

The plastic ball grid array (BGA) package has poor resistance to popcorn cracking, which occurs when high temperatures involved in soldering cause water vapor to expand rapidly. Popcorn cracking occurs at die attach paste, and therefore water absorption and desorption occurring in the vicinity of die attach paste must be studied. In this paper, we examine the mechanism of popcorn cracking in a BGA, particularly from the aspect of water absorption distribution. Water absorption was simulated by use of deuterium oxide, because the absorption performance of deuterium oxide approximates that of water. Deuterium oxide absorption distribution was measured by time of flight secondary ion mass spectroscopy (ToF-SIMS). We found that the water is absorbed mainly through the upper side of molded portion of the BGA package, and that absorption through the substrate is small. A BGA substrate has a laminated structure, and therefore water cannot penetrate the substrate first. On the basis of the results obtained in our study, we designed a BGA package system that is not prone to popcorn cracking.

Original languageEnglish
Pages (from-to)164-168
Number of pages5
JournalIEEE Transactions on Components and Packaging Technologies
Volume25
Issue number1
DOIs
Publication statusPublished - 2002 Mar 1

Keywords

  • BGA
  • Substrate
  • ToF-SIMS

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Electrical and Electronic Engineering

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