Metallic fullerene and MWCNT composite solutions for microelectronics subsystem electrical interconnection enhancement

Electromigration and galvanic corrosion can degrade microelectronic subsystems in the presence of hostile environmental conditions and over time. In this investigation electromigration (Ni²⁺, Cu²⁺, Pb²⁺/Sn²⁺) and galvanic corrosion were identified as occurring on tri-layer plated subsystem microelectronic subsystem surfaces. These conditions were determined to result in electrical signal degradation. A study was undertaken to pre-identify and subsequently characterize proposed contaminants, migrated ions, and elemental oxides that impact microelectronic function. In this study, tri-, quad, and multi-layer microelectronic test vehicles (TVs) were designed and fabricated. These vehicles were fabricated using aqueous electrolytic (10-20V DC, 2-5amp Swept bias) ionic deposition. The TV surface characterization included inspection and surface measurements by optical microscopy, scanning electron microscopy (SEM), electron diffraction spectroscopy (EDS), and electrical temperature humidity bias (THB) resistivity probe analysis. Subsystem surface plating and cross sectional analyses were performed to characterize plate integrity, thickness, potential ionic or electro mobility, galvanic corrosion, and interstitial plate cracking. TV plate thickness was measured with localized SEM analyses and ranged from 66-181 micro-inches. Multi-probe electrical conductivity measurements revealed a pre exposure humidity resistance of 0.5 - 0.8 ohms,and a post humidity exposure resistance of 1.6 - 0.8 ohms. Electrically conductive organic fullerenes and MWCNT composite materials with Au⁺ or Ag⁺ metallic composition were identified as potential integration candidates and interconnection media to achieve higher electrical conductivity. These materials present novel approaches to reduce electromigration, and localized galvanic corrosion formation that can occur in COTS subsystems. The results of identified electromigratory and galvanic elemental/compound species are presented. Candidate nanomaterial matrix solution paths are presented to reduce electromigration and galvanic corrosion occurring in microelectronic subsystems.