Strengthening the Electromigration Resistance of Nanoscaled Copper Lines by (3-aminopropyl)trimethoxysilane Self-Assembled Monolayer

Abstract

A nanoscaled copper (Cu) line is subject to aggravated electromigration after prolonged use, and thus the use of ultrathin barrier/ capping layer without degrading its electrical properties is increasingly needed. The aim of this study is to investigate the electromigration resistance of Cu interconnect strengthened by a self-assembled monolayer of (3-aminopropyl)trimethoxysilane (APTMS-SAM) and to develop an entirely wet chemically process for the fabrication of Cu lines. The Cu line with its bottom and sidewalls coated by an APTMS-SAM remains intact and yields the lowest resistivity of 1.80 μΩ-cm even after 500 °C annealing. The resistance of the Cu line against electromigration is remarkedly strengthened by using the APTMS-SAM as a molecular thick barrier due to a low relative diffusion rate of atoms under a constant current stressing, leading to an enhancement of thermal stability by at least 100 °C. The depletion of Cu atoms of a bare Cu line is observed to start from its top area, suggesting surface diffusion is the dominating electromigration mechanism. The enhancement of the Cu interconnect encapsulated by an APTMS-SAM is thus proposed, which indeed serves as a barrier to strengthen the electromigration resistance and enhance the thermal stability of the nanoscaled Cu line.

Electroless Metallization of the Elements: Survey and Progress

“…While the method required oxidation of substrates not bearing surface hydroxyl sites to enable SAM chemisorption, the use of amine ligand functional groups ,− eliminated the need for environmentally hazardous Sn species. Direct covalent binding of Pd species by the ligands facilitated deposition of adherent EL metal films without the need for substrate surface roughening, permitting fabrication of sub-100 nm features in EL metal. − More recently, others have improved the ligand-based process by replacing costly Pd species by cheaper first row transition metal ions, such as Co, ,, Cu, − or Ni, ,,− capable of autocatalyzing EL metal deposition upon reduction to zerovalent species. Some examples have been presented in the Cobalt section, Nickel section, and Copper section.…”

Anticipating Challenges in Optical Nanobiosensors for Global Detection of Respiratory Viruses and Emerging Threats

“…22 SAMS is the primary strategy to perform biofunctionalization, allowing the formation of ordered molecular assemblies through the adsorption of active surfactants on the surface. Since the head group reacts chemically with the substrate, 23 using alkyl silanes, alkanoic acids, and thiols is the best option. Nonetheless, conditions such as concentration of reactants to achieve homogeneous monolayers, physical (O 2 plasma) or chemical activation of nanomaterials (wet-chemistry for OHformation or bimolecular nucleophilic substitution-SN 2 mechanism), and the control of self-assembly (by temperature or non-polar solvents) must be handled without affecting the optical response (fluorescence or photoluminescence), which represent significant challenges at the nanoscale.…”