Interfacial Adhesion Energy of Ru–AlO Thin Film Deposited by Atomic Layer Deposition between Cu and SiO₂: Effect of the Composition of Ru–AlO Thin Film

Abstract

The effect of the composition of Ru–AlO thin films on the interfacial adhesion energy of an Ru–AlO thin film deposited by atomic layer deposition (ALD) between Cu and SiO2, which is a potential candidate for a Cu direct-plateable diffusion barrier, was evaluated using a four-point bending test. The interfacial adhesion energy increased with increasing AlO x content in the Ru–AlO thin films. The results were quantitatively correlated with the interfacial chemical bonding characteristics analyzed by X-ray photoemission spectroscopy, which showed that the adhesion energy is closely related to the formation of strong Al–O–Si bonds at film/substrate interfaces.

Atomic Layer Modulation of Multicomponent Thin Films through Combination of Experimental and Theoretical Approaches

“…In the spectrum for the [C-T] ALM film, the Ru 3 p 3/2 and Ru 3 p 1/2 peaks were shifted to 463 and 485 eV compared to the corresponding peaks at 461.5 and 483.6 eV in the spectrum for the [T-C] ALM film, respectively, indicating the formation of O–Ru bonds in the [C-T] ALM film. Furthermore, an O 1 s peak corresponding to O–Ru appeared at 529.5 eV in the XPS spectrum in Figure b, , which is consistent with the GPC interpretation of our proposed reaction model, as shown in Figure a. Al–O–Ru bonds had formed in the [C-T] ALM film, as shown in Figure b, and were confirmed by the HRTEM images in Figure a.…”

“…Instead, amorphous Al 2 O 3 seems to surround the metallic Ru and RuAlO x , similar to the RuAlO x film grown by typical supercycle ALD. 23,42 The EDS area-mapping images show a highly uniform mixture consisting predominantly of Ru (shown in red) and AlO x , as expected. (See Table S2 As discussed above, we have considered only the formation of Ru and AlO x phases based on surface reactivity and steric hindrance.…”

“…Interestingly, owing to steric hindrance and the stochastic adsorption of Carish and TMA on different surfaces during ALM, the Al 2 O 3 film was discontinuous despite the consecutive TMA and H 2 O pulsing in the same ALM cycle. Instead, amorphous Al 2 O 3 seems to surround the metallic Ru and RuAlO x , similar to the RuAlO x film grown by typical supercycle ALD. , The EDS area-mapping images show a highly uniform mixture consisting predominantly of Ru (shown in red) and AlO x , as expected. (See Table S2 for the concentration of each component of the [C-T] and [T-C] ALM films).…”

“…Al 2 O 3 formation dominates, which is consistent with the XPS results 42. The Ru and Al atomic concentrations are listed in Table1.…”

“…The O 1 s and Al 2 p peaks at 532 and 75.2 eV, respectively, in the XPS spectrum in Figure c indicate Al–OH, which was formed by the H 2 O pulse. ,, In the XPS spectrum for the [T-C] ALM film, peaks appeared at 531 and 73 eV in the O 1 s and Al 2 p energy regions, respectively, corresponding to Al 2 O 3 formation. Because the TMA precursor molecule is small, Al 2 O 3 formation dominates, which is consistent with the XPS results . The Ru and Al atomic concentrations are listed in Table .…”