TiN Diffusion Barrier Grown by Atomic Layer Deposition Method for Cu Metallization

Abstract

The effects on the impurity content, microstructure, resistivity and barrier characteristics of TiN film deposited by an atomic layer deposition (ALD) method have been evaluated. The TiN films were deposited on Si(100) substrates at 450 • C using the reactant gases TiCl 4 and NH 3 . The chemical and physical properties of ALD TiN thin films were measured. The TiN films had a randomly-oriented columnar grain microstructure. The chlorine content in the films was below the detection limit of Auger electron spectroscopy (< 0.5 at.%) due to the complete surface reaction by self-limiting reaction in ALD method. This low Cl content in film induced a low film resistivity of 120 µ cm. The barrier properties of this ALD films were tested by the etch-pit method. The result showed a retardation of the interdiffusion between Cu and Si in samples annealed for one hour at temperatures up to 450 • C.

Deposition of TiN and TaN by Remote Plasma ALD for Cu and Li Diffusion Barrier Applications

“…Uhm and Jeon reported a resistance increase using FPP measurements at temperatures above 600°C, Cu 3 Si peaks in XRD spectra at 550°C, and small defects using an etch pit test at 500°C for ALD TiN films deposited at 450°C using TiCl 4 and NH 3 . 38 Comparing these failure temperatures to our results indicate excellent barrier properties for the TiN films deposited by remote plasma ALD.…”

Atomic layer deposition of metal and nitride thin films: Current research efforts and applications for semiconductor device processing

“…(17) In a more recent report for TiN ALD using TiCl 4 precursor, Cu diffusion barrier failure temperature of around 500 °C was observed by an etch test, which was comparable to CVD TiN. (107) Since ALD TiN 53 had significantly lower Cl content than CVD TiN using the same precursors, it was suggested that the Cl content does not produce much difference in diffusion barrier property. Rather, the similar failure temperature was attributed to the same microstructure between the TiN films deposited by ALD and CVD.…”

“…(16) In other study, O content was measured as highest at surface region, which strongly supports that the O is incorporated by post deposition air exposure. (107) For MO-ALD TiN films, large increase in oxygen content with air exposure time was reported. (57) After 30 days exposure, the O content increases from 20 to 30-40 % with increase in resistivity, which is known as aging effect.…”

Recent Developments of Atomic Layer Deposition Processes for Metallization

“…It would be a simple choice of using metal halides and NH 3 in a basic AB‐type ALD reaction for conductive metal nitride deposition, however many thermal ALD metal nitrides are deposited in the form of an insulator at their highest oxidation state. Apart from TiN,8, 17–19, 24, 27, 31–34 only NbN x , 30, 35–38 MoN x ,8, 36, 37 and WN x 9 have been successfully deposited as conductive material using NH 3 in an AB sequence via thermal ALD. The resistivity of these materials is somewhat higher than that of TiN, from several hundreds to thousands µΩ cm.…”