Low Cost of Ownership scalable copper Direct Bond Interconnect 3D IC technology for three dimensional integrated circuit applications

This paper presents preliminary results of a copper-based direct bond interconnect (DBIreg) 3D integration process that has been developed to leverage foundry standard copper dual damascene and Ziptronix bond technology to achieve scalable, very low Cost-of-Ownership, 3D interconnects with minimum foundry adoption barrier. Results achieved include 100% operable arrays of 72,500 3D copper DBIreg interconnections on a 25 micron pitch with a 125degC thermal budget and 10 micron pitch 3D copper DBIreg interconnections with a 350degC thermal budget. DBIreg contact resistance and resistivity achieved are < 50 mOhm / connection and < 0.45 Ohm-um², respectively, using three or four micron diameter Cu DBIreg plugs and a TiW barrier layer. Reliability results include bare die that pass temperature cycling and HAST JEDEC tests.

Introduction

Three dimensional integrated circuits (3D ICs) are well known for increased performance resulting from reduced signal delays and power consumption. Adoption of this technology for volume semiconductor manufacturing will require other aspects of scalability, specifically cost reduction, to be realized.