(Color online) Schematic showing the Cu/barrier film stack that was studied. Failure occurred at the Cu/DDB interface for all adhesion measurements.
(Color online) Average interface fracture energy and corresponding standard deviation measured at the Cu/DDB interface showing effects of Cu purity and barrier composition.
Representative SEM micrographs of the (a) SiN low purity and (b) SiN high purity #2 samples.
(Color online) The average areal density of voids plotted as a function of interface fracture energy for each sample. Plating chemistries are denoted by different data point shapes (low purity – circles, high purity #1 – triangles, and high purity #2 – squares).
(Color online) XPS spectra performed on both the (a) Cu and (b) SiN fracture surfaces showing segregation of S and Cl impurities at the Cu/SiN interface.
(Color online) Interface fracture energy measured for each of the four different DDB (low purity Cu) samples plotted as a function of interfacial oxygen concentration.
Average in-film concentration of C, Cl, and S impurities as measured by SIMS depth profiling (Ref. 7).
Average number of stress-induced voids per 20 kX SEM image (∼ 200 μm2) in each sample.
Cl and S concentrations measured at the Cu and SiN fracture surfaces before and after sputtering away the interface region. Dashes signify that no peak was detected.
Interface oxygen concentration and dose measured for each DDB (low purity Cu) sample using SIMS.
Residual tensile stresses in the Cu film for all three SiN DDB samples as measured with XRD analysis.
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