Interfacial Phenomena in Cu Plating
EMSL Project ID
25657
Abstract
Electroplated Cu on a physical vapor deposited (PVD) Cu seed layer with a PVD Ta-based barrier is now an integrated process for the production of advanced interconnects for integrated circuits (IC), flat panel displays (FPD) and solar cells (SC). Staying on the curve of Moore's law and continued scaling of advanced interconnects will depend on the improving plating additive chemistry (accelerators, levelers and suppressors) to increase "superfill" capability, forming conformal liner/seed layers and producing defect-free copper. Noble metal liners (such as Ru, Rh, Ir, Os) deposited by atomic layer deposition/chemical vapor deposition (ALD/CVD) are especially attractive due to high oxidation resistance and conformality as opposed to PVD Cu seed layers that suffer from oxidation and overhang issues. The interfacial phenomena to be studied in this proposal includes a) transport through ultra-thin films (Cu migration through novel ALD/CVD liners/barriers, for example ALD Ru/TaN), b) surface mechanism and molecular level control of ALD/CVD deposition of noble metal liners, c) interfacial interactions of plating additives (accelerators, suppressors and levelers), and d) impact of interfaces (ALD liners vs PVD seed) on plated Cu film nucleation, growth and properties. It is critical to understand these interfacial phenomena to provide a scientific base to enable future scaling of advanced (high performance & low power) electronic (Microprocessors, Memories, FPD etc) devices and cost-efficient clean energy sources (solar and fuel cells). The approach to study these interfacial phenomena and to give insight into process development of future low power & high performance electronic devices and cost-effective clean energy sources includes developing a molecular understanding and physical-chemical models of a) interfacial interactions of organic, inorganic and metal-organic molecules as well as polymers and oligomers in plating solutions with the substrate surface during plating, b) ALD/CVD noble metal precursor properties and surface reaction mechanisms, c) the impact of substrate surface on copper microstructure, composition and film properties, and d) transport of Cu through ultra-thin liners, by using advanced deposition (Plating, ALD, MO CVD) and characterization techniques (SIMS, RBS, XRD, XPS, STM, TEM, SEM).
Anticipated research output includes a) the experimental characterization of Cu deposition onto ALD liners in the presence of organic additives, accompanied by a theoretical framework that allows for the interpretation of the experimental results and understanding of optimal molecular structures of interfaces, b) the experimental characterization of ALD metal precursors with the models explaining the effect of functional groups on thermal stability, volatility and reactivity, c) both the initial stages of the Cu on ALD liners and its impact on the final film properties will be summarized, and d) the physical chemical models that accounts for both the initial deposition process, deposition kinetics and film properties will be developed. These results advance interface science by establishing fundamental relationships between organic, inorganic and metal-organic molecules adsorbed on the substrate and metal nucleation, deposition kinetics and film properties. These results will be published in peer-reviewed journals.
Project Details
Project type
Large-Scale EMSL Research
Start Date
2007-06-07
End Date
2008-11-11
Status
Closed
Released Data Link
Team
Principal Investigator
Team Members