Cross-sectional elastic imaging and defect detection in low-k spin-on dielectrics

Author

Muthuswami, L. ; Moyer, E.S. ; Li, Z. ; Geer, R.E.

Author_Institution

Inst. for Mater., Univ. at Albany, NY, USA

fYear

2002

fDate

2002

Firstpage

239

Lastpage

241

Abstract

A novel cross-sectional characterization technique for depth-dependent nanomechanical profiling of low-k dielectrics has been developed based on ultrasonic force microscopy. So-called CS-UFM has been demonstrated on silicon-based, spin-on dielectrics (SOD) used for gap-fill in 0.15 μm trenches in an SiO₂ test structure. The SiO₂ trench walls were coated with a thin (∼24 nm) PECVD Si₃N₄ layer. CS-UFM imaging clearly differentiated the SOD, SiO₂ and Si₃N₄ on the basis of elastic modulus. Variations in the elastic uniformity of the SOD and Si₃N₄ were observed. In addition, mechanical defects were identified within the SOD-filled trenches. Initial HF-etch testing suggested the defects represented localized areas of modified SOD composition or intra-trench voids.

Keywords

acoustic microscopy; dielectric thin films; elastic moduli; etching; fault location; integrated circuit interconnections; integrated circuit metallisation; mechanical testing; permittivity; spin coating; ultrasonic imaging; voids (solid); 0.15 micron; 24 nm; CS-UFM imaging; HF; HF-etch testing; PECVD Si₃N₄ layer coating; SOD; SOD-filled trenches; SiO₂ test structure trenches; SiO₂ trench walls; SiO₂-Si₃N₄; cross-sectional characterization technique; cross-sectional elastic imaging; defect detection; depth-dependent nanomechanical profiling; elastic modulus; elastic uniformity; gap-fill; intra-trench voids; localized modified SOD composition areas; low-k spin-on dielectrics; mechanical defects; silicon-based spin-on dielectrics; ultrasonic force microscopy; Acceleration; Circuit testing; Crystallization; Dielectric devices; Dielectric materials; Force measurement; Mechanical factors; Microscopy; Spatial resolution; Ultrasonic imaging;

fLanguage

English

Publisher

ieee

Conference_Titel

Interconnect Technology Conference, 2002. Proceedings of the IEEE 2002 International

Print_ISBN

0-7803-7216-6

Type

conf

DOI

10.1109/IITC.2002.1014945

Filename

1014945