Direct Bond Interconnect (DBI®) Technology As An Alternative to Thermal Compression Bonding
Authors: Guilian Gao, Ph.D., Gill Fountain, Paul Enquist, Ph.D., Cyprian Uzoh, Liang Frank Wang, Ph.D., Scott McGrath, Bongsub Lee, Ph.D., Willmar Subido, Sitaram Arkalgud, Ph.D., Laura Mirkarimi, Ph.D. Company: Invensas Corporation Date Published: 10/18/2016
IWLPC (Wafer-Level Packaging)
Abstract: The industry standard interconnect technology for fine pitch 2.5D assembly and 3D stacking is thermal compression bonding of solder capped µbumps. This technology has several challenges limiting the widespread adoption in high volume production. While the implementation of the technology at 40 µm pitch is already challenging, the likelihood of extending this technology to 10µm pitch is slim due to pattern processing complexity, stacking alignment accuracy and unstable solder material. Alternative interconnect approaches such as solid metal connection without solder reflow, direct copper to copper (Cu to Cu) bonding, are more feasible for further pitch scaling. This paper presents the latest development in Direct Bond Interconnect DBI®, a Cu-Cu interconnect technology for both die-to-wafer (D2W) and die-to-die (D2D) stacking. Daisy chain dies were prepared with similar dimensions and interconnect pitch to a typical high bandwidth memory (HBM) die. The daisy chain dies were DBI® bonded onto a host wafer that represents the controller in a HBM stack. Process development is discussed and preliminary electrical testing results are presented.