Title :
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
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;
Conference_Titel :
Interconnect Technology Conference, 2002. Proceedings of the IEEE 2002 International
Print_ISBN :
0-7803-7216-6
DOI :
10.1109/IITC.2002.1014945
