Open AccessArea-Selective Electroless Deposition of Cu for Hybrid Bonding
Author(s) -
Fumihiro Inoue,
Serena Iacovo,
Zaid El-Mekki,
Soon-Wook Kim,
Herbert Struyf,
Eric Beyne
Publication year - 2021
Publication title -
ieee electron device letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.337
H-Index - 154
eISSN - 1558-0563
pISSN - 0741-3106
DOI - 10.1109/led.2021.3124960
Subject(s) - engineered materials, dielectrics and plasmas , components, circuits, devices and systems
This letter describes the use of area-selective electroless Cu deposition for topography control of Cu-SiCN hybrid bonding pads. The electroless deposition of Cu allows one to obtain protrusions on hybrid bonding Cu pads without further polishing optimization. A recessed Cu pad after chemical mechanical polishing becomes a protrusion after electroless deposition. This indicates that the electroless Cu film was selectively deposited on Cu, without deposition on the SiCN surface. A void-free Cu-Cu bonding interface was observed after annealing at 350 °C with an electroless Cu layer at the interface. 100% electrical connection was obtained at 1.4- $\mu \text{m}$ pitch where the deposition thickness was on target.