Removing metal debris from thermosetting EMC powders by Nd-Fe-B permanent magnets

Yowching Liaw, Jung Hua Chou, Shouyen Chao

Research output: Contribution to journalConference articlepeer-review


During the preparation of thermosetting encapsulation molding compounds (EMCs) for semiconductor packaging, metal debris are always present in the EMC powders due to the hard silica fillers in the compound. These metal debris in the EMC powders will cause circuit shortage and therefore have to be removed before molding. In this study, Nd-Fe-B permanent magnets are used to remove these debris. The results show that the metal debris can be removed effectively as the rate of accumulation of the metal debris increases as time proceeds in the removing operation. The removal effectiveness of the debris is affected by both the magnetic flux density and the flow around the magnet. The wake flow behind the magnet is a relatively low speed recirculation region which facilities the attraction of metal debris in the powders. Thus, the largest amount of the accumulated EMC powders occurs downstream of the magnet. Hence, this low speed recirculation region should be better utilized to enhance the removal efficiency of the metal debris.

Original languageEnglish
Article number03009
JournalMATEC Web of Conferences
Publication statusPublished - 2017 Oct 25
Event1st International Conference on Composite Material, Polymer Science and Engineering, CMPSE 2017 - Toyama, Japan
Duration: 2017 Jun 242017 Jun 25

All Science Journal Classification (ASJC) codes

  • Chemistry(all)
  • Materials Science(all)
  • Engineering(all)


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