Wire Bonding to Advanced Copper-Low-K Integrated Circuits, the Metal/Dielectric Stacks, and Materials Considerations
George G. Harman, C E. Johnson
There are three areas to consider when planning to wire bond to new chips having copper bond pads and low dielectric-constant polymers imbedded beneath them (Cu/LoK). These Are: 1/. The Top Surface Metal/Inhibitor Coating for Bondability. (a) Metal(s) (b) OSPs and other non-metal oxidation supressants. 2/. The low dielectric constant materials. (a) Mechanical properties (b) Dielectric/barriers/electrical. 3/. Under-Pad mechanical support structures. There are also various polymer/metallurgical interactions that can occur during the wire bonding interconnection process when bond pads are located over low modulus polymers (or a higher modulus if heated near its glass transition temperature, Tg, during bonding). Some of the same problems are encountered when bonding to multichip modules (MCM-d and-L), polymer buildup-layers on PCBs, PBGAs, flex circuits, etc., and they share the same understanding and solutions. However, special conditions exist for each of the above. These are discussed in detail with special emphasis on Cu/LoK structures and bondability problems.
and Johnson, C.
Wire Bonding to Advanced Copper-Low-K Integrated Circuits, the Metal/Dielectric Stacks, and Materials Considerations, Proc., IMAPS, Baltimore, MD, USA
(Accessed December 9, 2023)