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Title: Deposition and application of electroless Ni-W-P under bump metallisation for high temperature lead-free solder interconnects
Author: Liu, Li
ISNI:       0000 0004 7651 3005
Awarding Body: Loughborough University
Current Institution: Loughborough University
Date of Award: 2016
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A reliable and robust diffusion barrier, commonly known as under bump metallisation (UBM), is indispensable in solder interconnects in order to retard the interfacial reaction rate, hence the growth of intermetallic compounds (IMCs). However, electroless Ni-P coatings are not adequate to inhibit interfacial reactions effectively since the formation of columnar structure and voids in the crystalline Ni3P layer in hybrid automotive devices (operating temperature above 300ºC) can significantly deteriorate the mechanical integrity of solder joints. In this thesis, electroless Ni-W-P coatings, as an effective UBM capable to serving under high temperature (up to 450ºC), are developed, characterised and subsequently applied onto the high temperature lead-free solder interconnects.
Supervisor: Not available Sponsor: Loughborough University
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available
Keywords: Electroless Ni-W-P deposition ; Crystallisation characteristics ; Lead-free high temperature solders ; Diffusion barrier characteristics ; Power electronics ; Interfacial reactions ; IMCs