Area bonding conductive epoxy adhesives for low cost grid arraychip carriers

摘要

This paper describes a new type of Z axis epoxy film adhesive,called a_rea b_onding c_onductive (ABC) epoxies, toreplace solder and solder balls for surface mounting grid array chipcarriers. The ABC adhesives are made by a low cost screen printingprocess, starting from customer-supplied artwork, so that the conductiveepoxy regions are located only at the desired bond pad locations.Reliability data, presented for plastic and LTCC packages attached toFR-4 boards with these adhesives, show better resistance to thermalcycling and thermal shock than soldered packages. This paper alsodescribes a new low cost copper lidded pad array chip carrier, called aCu-PAC. This uses an ABC epoxy for die and for substrate attach. TheCu-PACs have the potential for major cost savings, size reduction andimproved heat removal compared to present molded plastic grid arraypackages