20um Pd-copper wire bonding process development on ASM Eagle60 AP

Copper wire has been popular in these years when facing ever-increasing gold prices. Recently, Pd-coated Cu wire is emerging as an alternative to bonding with bare Cu wire to prevent copper oxidation during the bonding and improve manufacturability. In recent years, many papers were published focusing on KNS bonder platform development. KNS became more and more popular in copper wire bonding field, No much attention was paid on ASM bonder platform. In this paper, a SMOS8 device with 2.0um bond pad thickness was selected as test vehicle in developing the wire bond process on ASM bonder platform. Three types of 1st bond formation approach were studied: base force, end force and contact force. 1st bond formation, aluminum splash, IMC coverage and manufacturability were compared as response. Evaluation shows high end force plus contact force is effective 1st bond formation method for pd copper wire. Bond pad metal peeling issue post wire pull test were also resolved bonding with high end force and contact force concept. DOE (Design of Experiment) were used to optimize 1st bond parameter. Two 2nd bond formation approaches were evaluated: scrub and enhancer smooth.2nd bond formation, stitch pull strength and capillary wore out were compared as response. Evaluation shows 2nd bond scrub and enhancer smooth are all effective method to form 2nd bond with parameter optimization. With optimized parameter for two bonding concept, high stitch pull strength, longer capillary life and good manufacturability. Last, the device with optimized parameter pass Bia-HAST and Temperature cycle and high temperature storage.