Real time contact resistance measurement to determine when microwelds start to form during ultrasonic wire bonding
2013 (English)In: Microelectronic Engineering, ISSN 0167-9317, Vol. 104, 114-119 p.Article in journal (Refereed) Published
We prove that we can, using contact resistance as a tool, determine the instant when the bonding process starts, i.e. microwelds start to form during ultrasonic bonding. This knowledge permits us to reduce the uncertainty in the estimated bonded area by 5-18%. We proved our claim by combining a real-time contact resistance measurement, aborted ultrasound bonding, and classical SEM analysis of the bonded surfaces. We measured and analyzed, using a 4-wire Kelvin cross setup, the contact resistance of 25 μm by diameter AlSi(1%) wires bonded to a gold pad. The microweld area of 69 bonds was determined. We focused on inferring exactly when do the microwelds start to form. Post hoc analysis showed a linear correlation between the total microweld area and the time elapsed since the initial contact resistance drop. This work may help minimizing the sonication impact which may allow working with thin bond wires and fragile substrates.
Place, publisher, year, edition, pages
2013. Vol. 104, 114-119 p.
Contact resistance, Microweld formation, Real-time, Ultrasound, Wire bonding
Engineering and Technology Natural Sciences
Research subject Engineering Science with specialization in Materials Science
IdentifiersURN: urn:nbn:se:uu:diva-194920DOI: 10.1016/j.mee.2012.12.003ISI: 000315245000022OAI: oai:DiVA.org:uu-194920DiVA: diva2:606570