Novel Low-Cost Sol-Gel Derived Materials for Nano-Structured and Repairable Interconnects Conference

Aggarwal, AO, Abothu, IR, Raj, PM et al. (2003). Novel Low-Cost Sol-Gel Derived Materials for Nano-Structured and Repairable Interconnects . SMART BIOMEDICAL AND PHYSIOLOGICAL SENSOR TECHNOLOGY XI, 5288 943-948.

cited authors

  • Aggarwal, AO; Abothu, IR; Raj, PM; Ravi, D; Sacks, MD; Tummala, RR


  • As ICs shift towards less than 100 nm features, the pitch of area array I/Os of the nano ICs move towards 20-100 microns as suggested by International Technology Roadmap for Semiconductors (ITRS). The Packaging Research Center (PRC) at Georgia Tech has been exploring and evaluating novel approaches using nanomaterials and processes for fine pitch wafer level packages. Most of the compliant interconnects that are currently being developed have inductance and resistance higher than desirable. There is definitive evidence that nano-structured interconnects can provide better resistance to crack growth and fatigue resistance and hence improve mechanical reliability without sacrificing the electrical properties. Current approaches to interconnects such as reflowed solder paste and electroplated interconnects cannot easily achieve nano-grained structures and also impose restrictions on the processibility. For example, screenprinting solder pastes cannot achieve very fine pitches, while electroplated interconnects are restricted to a few material systems. This paper proposes solution derived (sol-gel based) nano-grained copper and lead free solders for finepitch high strength nano-structured interconnects. In this process, metal-based organic polymer solutions are heattreated in reducing atmosphere to form metallic copper and lead-free solders (Sn-Ag-Cu). The key is to achieve ultra homogeneous mixing at atomic to molecular level. The precursors were mixed in solvent and refluxed under inert atmosphere at 125°C to form metallic Cu/Sn-Ag-Cu complex solutions. The homogenous gel obtained from the hydrolysis of sol-gel precursor solution is heat treated under inert atmosphere at temperatures below 350°C to achieve the desired compositions. Among a large number of methods for metal deposition, sol-gel technology, based on thermal decomposition of metal-organic compounds, can prove to be the most convenient and inexpensive for industrial applications.

publication date

  • December 1, 2003

start page

  • 943

end page

  • 948


  • 5288