Perfectly conformal deposition into deep trenches or filling of them without keyhole formation is achieved (see Figure) by atomic layer deposition (ALD). Good conformality can be obtained with other CVD processes, but the unique surface‐controlled, self‐limiting growth mechanism of ALD may give the technique significant advantages over other methods for future generation IC technology.
Diffusion barrier materials, TiN and WN, were deposited by atomic layer deposition (ALD). The chlorine concentration of the TiN film was as low as 1.2 at.-%, and resistivity was below 200 lX cm. Ultra high aspect ratio (AR = 85) trenches were used to assess step coverage. Tungsten nitride film, deposited from WF 6 and ammonia, was found to have high resistivity, although the residue content was low. The barrier deposition compatibility was studied using the copper surface exposed on the bottom of vias in the copper dual-damascene structure. The deposition on copper of both TiN and WN was found to be very challenging.
At present flexible electronic devices are under extensive development and, among them, flexible organic light-emitting diode displays are the closest to a large market deployment. One of the remaining unsolved challenges is high throughput production of impermeable flexible transparent barrier layers that protect sensitive light-emitting materials against ambient moisture. The present studies deal with the adaptation of the atomic layer deposition (ALD) process to high-throughput roll-to-roll production using the spatial ALD concept. We report the development of such a process for the deposition of 20 nm thickness Al2O3 diffusion barrier layers on 500 mm wide polymer webs. The process uses trimethylaluminum and water as precursors at a substrate temperature of 105 °C. The observation of self-limiting film growth behavior and uniformity of thickness confirms the ALD growth mechanism. Water vapor transmission rates for 20 nm Al2O3 films deposited on polyethylene naphthalate (PEN) substrates were measured as a function of substrate residence time, that is, time of exposure of the substrate to one precursor zone. Moisture permeation levels measured at 38 °C/90% relative humidity by coulometric isostatic–isobaric method were below the detection limit of the instrument (<5 × 10−4 g/m2 day) for films coated at web moving speed of 0.25 m/min. Measurements using the Ca test indicated water vapor transmission rates ∼5 × 10−6 g/m2 day. Optical measurements on the coated web showed minimum transmission of 80% in the visible range that is the same as the original PEN substrate.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.