This thesis proposal outlines a research plan focused on the development and characterization of lead-free alloy micro-bumps for flip-chip technology, utilizing sputtering deposition. Sputtering, a vacuum deposition technique, offers precise control over alloy composition and microstructure, crucial for achieving reliable and robust micro-bumps. This research will investigate the deposition of promising lead-free alloys, such as Sn-Ag-Cu, Sn-Bi or Sn-In, onto silicon substrates with under-bump metallization. The study will encompass optimizing sputtering parameters to control film morphology, uniformity, and adhesion.
The goal is to establish a robust sputtering process for fabricating high-quality lead-free alloy micro-bumps, contributing to the advancement of sustainable and reliable flip-chip packaging. This research builds upon previous work demonstrating the feasibility of sputtering for micro-bump fabrication and the performance of various lead-free alloys. The findings will provide valuable insights into the relationship between sputtering parameters, alloy composition, and micro-bump performance, enabling the development of optimized lead-free interconnects for next-generation Systems-in-Packages (SiPs) [1, 2].
The work will be organised as follow:
