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2014
Conference Paper
Titel
Heavy-Wire Bond Manipulation with Laser to Increase Reliability and as Enabler for Thermography based On-line Process Control
Abstract
Investigations regarding the failure behavior of heavy wire bonds show a significant decrease of cycles in strength with increasing wire diameter. The article explains the reasons theoretically. Based on the theory, possibilities to increase reliability are discussed. The innovation about this is the shaping of a chute on the bonding surface. This has to happen in a way that the current ampacity is not reduced. A laser will therefore cut across the bonding surface crosswise to the course of the wire. Previously the particular depth of cut is determined by simulation. The simulations prove the theoretically predicted enhancement of the reliability true. In addition, the method can be used as "non-destructive" in-situ measurement for quality assurance, since the crack growth can be derived from the thermography directly in the notches. The notches work as a magnifier for the thermography camera and eliminate the black coloring as a precondition in typical thermography. The research work is carried out within the project RoBE partially which is funded by BmBF; the manufacturing method and the geometric shapes have been patented.