Hybrid Bonding as Crucial Technology for Future Applications
Prof. Viorel Dragoi
EV Group, Austria
Abstract:
Hybrid Bonding as Crucial Technology for
Future Applications
Dr. Viorel DRAGOI, EV Group, Austria
Hybrid wafer-to-wafer bonding gained over the past decade a significant interest as it can
provide major advantages in fabrication of wafer-level interconnects. The process is extremely
challenging in terms of surface preparation, as substrates must accommodate two types of
bonding processes simultaneously (dielectric-dielectric low temperature fusion bonding and
Cu-Cu thermo-compression bonding localized at bonding pad level).
The fabrication of the bonding surfaces has to consider a specific topography (metal recess
with respect to dielectric surface within single digit nanometers, dielectric surface with very low
micro roughness - less than 0.5 nm, etc,) with very high uniformity across300 mm diameter
wafers. The bonding process must ensure a high alignment accuracy (sub-micrometer) across
the entire wafer and low temperature processing, within the COS thermal budget (<4009C).
After the bonding process one of the two bonding partners has to be thinned down: in case
the substrates preparation was not performed according to specifications or the bonding
process was not properly performed, the structures on the wafer will be distorted, making
further processing more difficult, time consuming and adding costs. Thus, substrates quality
and accurate bonding process control are of a very high importance.
An overview of the main aspects related to hybrid bonding will be presented. The main
specifications and some of the main challenges of this technology will be reviewed with respect
to their impact on process results. The main challenges with respect to process equipment will
be reviewed. The importance of new metrology and investigation methods adoption will be
emphasized.