Evaluation of thin copper wire and lead-free solder joint strength by pullout tests and wire surface observation

Naoya Tada, Takuhiro Tanaka, Takeshi Uemori, Toshiya Nakata

Research output: Contribution to journalArticle

2 Citations (Scopus)

Abstract

Copper wires have been attracting much attention for Large Scale Integration (LSI) bonding because of their excellent mechanical and electrical properties, in addition to their low material cost. The ends of these wires are usually joined to pads or through-holes on a printed circuit board, and lead-free soldering is one of the popular bonding methods. Since the deformation resistance of solder is lower than that of copper, especially in slow deformation due to creep, the strain tends to be increased in the solder and concentrated near the copper/solder joint interface. Thus, fracture frequently occurs at this interface and may influence the quality of the product. It is therefore important to evaluate the bonding strength of thin copper wire and lead-free solder. In this paper, pullout tests of thin copper wire from lead-free solder were carried out, and the pullout behavior of the wires was observed. The bonding strength was evaluated based on the actual bonded area on the copper wire surface. Finally, the strength of the thin copper wire/solder joint was summarized using the shear and tensile strengths of the copper/solder interface as well as the tensile strength of the copper wire.

Original languageEnglish
Article number255
JournalCrystals
Volume7
Issue number8
DOIs
Publication statusPublished - Sep 1 2017

Fingerprint

solders
Copper
wire
Wire
copper
evaluation
Soldering alloys
tensile strength
Tensile strength
Lead-free solders
LSI circuits
soldering
large scale integration
shear strength
Soldering
printed circuits
circuit boards
Printed circuit boards
Shear strength
Creep

Keywords

  • Bonding strength
  • Copper wire
  • Lead-free solder
  • Pullout test

ASJC Scopus subject areas

  • Chemical Engineering(all)
  • Materials Science(all)
  • Condensed Matter Physics
  • Inorganic Chemistry

Cite this

Evaluation of thin copper wire and lead-free solder joint strength by pullout tests and wire surface observation. / Tada, Naoya; Tanaka, Takuhiro; Uemori, Takeshi; Nakata, Toshiya.

In: Crystals, Vol. 7, No. 8, 255, 01.09.2017.

Research output: Contribution to journalArticle

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