Highly Reliable Cu Interconnect Using Low-Hydrogen Silicon Nitride Film Deposited at Low Temperature as Cu-Diffusion Barrier

Abstract

We demonstrated highly reliable Cu interconnects using a high-quality silicon nitride film grown at temperatures below 300 C. The low-temperature silicon nitride (LT-SiN) film, which was used as a Cu-diffusion barrier layer and a final passivation layer, was deposited at 275 C by plasma-enhanced chemical vapor deposition at a low SiH 4 flow ratio. The low SiH 4 flow ratio was due to the use of a highly dilute nitrogen flow, leading to the generation of many nitrogen radicals or ions in the plasma. These radicals or ions might reduce the hydrogen concentration and defect density of the film. As a result, a stoichiometric silicon nitride (Si 3 N 4 ) film with a low hydrogen concentration was successfully obtained. By applying this LT-SiN film in 130-nm-node Cu interconnects for magnetoresistive random access memory, highly reliable via-hole electromigration (Via-EM) and line-to-line time-dependent dielectric breakdown (TDDB) characteristics were obtained.

The role of Ru passivation and doping on the barrier and seed layer properties of Ru-modified TaN for copper interconnects

“…4 are plotted in Fig. 11 The average Cu binding energies (E avg bind and E avg bind * ) and the average Cu-Cu interaction energies (E avg Cu−Cu ) extracted from all 13 cluster adsorptions are listed in Table I. The strongest overall binding of Cu and Cu n (E avg bind and E avg bind * ) is observed on the Ru 100 surface and the weakest overall binding is found on the Ru 75 and the clean TaN surfaces.…”

“…[3][4][5][6][7] The first diffusion barriers used were Ta and Si 3 N 4 . 4,[8][9][10][11] A wide variety of materials has been studied as alternative barrier materials in order to drive scaling and performance. [12][13][14][15][16][17] Most of these materials are binary or ternary materials involving refractory metals, such as Ta, Mo and Os.…”

Control of the Cu morphology on Ru-passivated and Ru-doped TaN surfaces – promoting growth of 2D conducting copper for CMOS interconnects

“…There is a significant level of experimental work on different diffusion barrier materials since they were first used when the industry changed from Al to Cu interconnects in 1997. [13,14,23,24,[15][16][17][18][19][20][21][22] These barrier materials can be divided into several different categories, according to the classification of Kaloyeros and Eisenbraun. [25] Of these, the refractory metals, e.g.…”

Control of Cu morphology on Ru-passivated and Ru-doped TaN Surfaces – promoting growth of 2D conducting copper for CMOS interconnects

“…There has been a signicant level of experimental work on different diffusion barrier materials since they were rst used when the industry changed from Al to Cu interconnects in 1997. [13][14][15][16][17][18][19][20][21][22][23][24] These barrier materials can be divided into several different categories, according to the clas-sication of Kaloyeros and Eisenbraun. 25 Of these, refractory metals, e.g.…”