Title :
Bumpless interconnects formed with nanowire ACF for 3D applications
Author :
Jing Tao ; Mathewson, Alan ; Razeeb, Kafil M.
Author_Institution :
Tyndall Nat. Inst., Univ. Coll. Cork, Cork, Ireland
Abstract :
Nanowire ACF is fabricated by template synthesis method based on electrochemical deposition. Due to the high aspect ratio of length to diameter (50:1), the nanowires can act as compliant conductors to electrically connect the bumpless dies with a small bonding force. In this work, an interconnection resistance of 90 mΩ per 40 × 40 μm2 pad is measured for the Cu NW-ACF bonding between two Au bumpless dies. An increasing leakage current up to 10-6 A in x-y plane is observed with the elevated voltage till 20 V for a pitch size of 80 μm. A comparison study of NW-ACF to conventional particle based ACF is carried out. The bonding mechanisms of the NW-ACF bonding to bumped and bumpless dies and its difference to particle ACF bonding is revealed by bonding interface analysis.
Keywords :
electrodeposition; integrated circuit bonding; integrated circuit interconnections; leakage currents; nanowires; 3D applications; anisotropic conductive film; bonding force; bonding interface analysis; bonding mechanisms; bumpless dies; bumpless interconnects; compliant conductors; electrochemical deposition; interconnection resistance; leakage current; nanowire ACF; particle ACF bonding; template synthesis method; Bonding; Bonding forces; Gold; Insulation; Leakage currents; Resistance; Three-dimensional displays; Nanowire ACF; bonding interface analysis; bumpless interconnect; flip-chip bonding; interconnectio resistance; leakage current;
Conference_Titel :
3D Systems Integration Conference (3DIC), 2014 International
DOI :
10.1109/3DIC.2014.7152154
