Compensation of Surface Roughness Using an Au Intermediate Layer in a Cu Direct Bonding Process

Hirokazu Noma*, Takumi Kamibayashi, Hiroyuki Kuwae, Naoya Suzuki, Toshihisa Nonaka, Shuichi Shoji, Jun Mizuno

*この研究の対応する著者

研究成果査読

2 被引用数 (Scopus)

抄録

Copper-copper (Cu-Cu) direct bonding assisted by direct immersion gold (DIG) was demonstrated. Cu-Cu direct bonding is a critical technology for inductively coupled memory interconnections. To solve the problems of conventional methods of Cu-Cu direct bonding, a plating process using DIG to form an intermediate layer was selected. The concept of the developed bonding process is to use deformation of DIG to compensate for the surface roughness of the Cu substrates during application of pressure and annealing. Using this method, precise surface flattening of Cu substrates is not necessary. Bonding can be achieved even in an air atmosphere. A sample bonded at a temperature of 350°C failed within the chip in a shear test. It was found that bonding can be achieved when the gold (Au) thickness is greater than the half of the surface roughness of Cu at the bonding temperature. Transmission electron microscopy-energy-dispersive x-ray spectroscopy revealed that Au diffused into Cu during bonding. The diffusion constant of Au into Cu was investigated through a numerical calculation. The obtained results showed good agreement with the literature values.

本文言語English
ページ(範囲)5403-5409
ページ数7
ジャーナルJournal of Electronic Materials
47
9
DOI
出版ステータスPublished - 2018 9 1

ASJC Scopus subject areas

  • 電子材料、光学材料、および磁性材料
  • 凝縮系物理学
  • 電子工学および電気工学
  • 材料化学

フィンガープリント

「Compensation of Surface Roughness Using an Au Intermediate Layer in a Cu Direct Bonding Process」の研究トピックを掘り下げます。これらがまとまってユニークなフィンガープリントを構成します。

引用スタイル