Disputas: Stéphane Léonard Kuziora

Stéphane Léonard Kuziora disputerer for doktorgraden i Applied Micro- and Nanosystems. Avhandlingen handler om metallurgisk bonding under ekstreme temperaturer, til bruk i mikroelektronikk.

25 Mar

Praktisk informasjon

  • Dato: 25 mars 2025
  • Tid: kl. 10.15 - 13.15
  • Sted: Vestfold, Auditorium A1-36 og Zoom
  • Last ned kalenderfil

    • Lenke til digital deltakelse (Zoom)

     

    Program 

    Kl 10.15. Prøveforelesning: "CALPHAD construction and assessment of phase diagrams for alloy solidification and soldering”

    Kl 12.15. Disputas: Advancing metallurgical bonding for microelectronics, through low-temperature metal joining, high temperature resistant bonds, and the investigation of cavitation-induced voiding

    Veiledere

    • Hovedveileder: Professor Knut Eilif Aasmundtveit ved Universitetet i Sørøst-Norge
    • Medveiledere: Førsteamanuensis Hoang-Vu Nguyen ved Universitetet i Sørøst-Norge

     

     

Har du spørsmål?

Stéphane Léonard Kuziora skal forsvare avhandlingen sin for graden philosophiae doctor (ph.d.) ved Universitetet i Sørøst-Norge. 

Disputas Stéphane Léonard Kuziora

Han har fulgt doktorgradsprogrammet i Applied Micro- and Nanosystems ved Fakultet for teknologi, naturvitenskap og maritime fag. 

Alle interesserte er velkomne til å følge prøveforelsningen og disputasen.

Sammendrag

Stéphane Léonard Kuziora presents his PhD research on metallurgical solid-liquid interdiffusion (SLID) bonding at the University of Southeastern Norway (USN). His academic journey began with a degree in chemical engineering from Lakehead University in Canada, followed by a master’s in micro and nano technology at USN before embarking on his PhD studies.


His PhD introduces a promising low temperature bonding system, presenting the first micrographs and description of the Ag-(In-Bi) SLID system, while demonstrating bonding at 150 °C with Ag substrates and an In-Bi foil of 78.5 at%In. The bonds can then be re-heated without melting, having a theoretical temperature stability up to ⁓480–570°C. This can enable the unique bonding of piezo-electric materials (PEM) at temperatures lower than their Curie temperature, eliminating the need for costly magnetic re-poling. Additionally, the technique supports metal-polymer composite materials and interconnection joining for temperature-sensitive electronic systems. The technique is also ideal for advancing computing density through 3-D stacking and fine interconnection pitch at the micrometer length.  


A phenomenon unique to the Ag-(In-Bi) SLID system was discovered and termed, “Bi precipitation” where pockets of Bi were formed behind the original bonding surfaces. Unlike similar occurrences in other SLID systems, experimental evidence with solid-state bonding of the Ag-(In-Bi) system showed the Bi pockets are formed through a dissolution mechanism. This bonding also demonstrated an even lower bonding temperature of 65 °C, being theoretically stable to ⁓166 °C.


Investigation into the high temperature resistant bonds found in the Ni-Sn SLID system revealed unique cavitation-induced voiding. Thermodynamic modelling confirmed that intermetallic growth within enclosed liquid Sn pockets generates sufficient pressure to initiate cavitation, a previously unexplored consideration in metallurgical bonding. The work presents a first approach and focused discussion to cavitation-induced voiding and may be utilized to enhance the reliability of SLID bonds by reduced voiding.