Die Attach Epoxy Delamination Study on Low RDs(on) Device

Delamination or separations between surfaces of die attach epoxy and leadframe has become a barrier for Molded Leadless Package (MLP) to meet Moisture Sensitivity Level (MSL) 1 requirement as per JEDEC standard. Besides, Mosfet devices that require low static Drain-Source On-State resistance RDs(on) and thermal resistance performance are significantly affected if the delamination is observed between the epoxy and die attach paddle (DAP). Hence, an evaluation has been carried out with two set of different materials combination namely epoxies (Epoxy A & B) and different surface treatment of leadframe (LF X & Y). MLP package with body size of 5x6 mm sq has been selected as test vehicle because of its low RDs(on) and MSL 1@260degC requirement. Objective of this evaluation is to fulfill these two requirements while to ensure there is no delam between epoxy and DAP layers. In this evaluation, package is reflowed at 260degC and subjected to 500 temperature cycles. Scanning Acoustic Tomography (SAT) and electrical test are used to check for package delamination and Rdson value respectively. Results show that only combination of LF Y and Epoxy B shows no package delamination and meeting Rdson values.