Broadband UV-assisted thermal annealing of low-k silicon carbonitride films using a C-rich silazane precursor

Abstract

Low-k dielectric silicon carbonitride (SiCxNy) films are deposited by plasma-enhanced chemical vapor deposition using a carbon-rich silazane precursor, N-methyl-aza-2,2,4-trimethylsilacyclopentane (SiC7NH17), at 100 °C. The post-treatments of SiCxNy films are carried out by thermal annealing and a broadband UV-assisted thermal annealing (UV-annealing) at 400 °C for 5 min. Compared to the thermal annealing treatment, UV-annealing can improve both dielectric and mechanical properties of low-k SiCxNy films. Under thermal annealing, SiCxNy films show great thermal stability, but little structural change. In contrast, upon UV-annealing, most of the Si–H and N–H bonds are broken up, which induces more Si–N cross-linking and converts Si–C matrix into Si–N matrix. The ethylene bridges in Si–(CH2)2–Si also remain intact, but the unbridged hydrocarbons in Si–(CH2)2–N and Si–CH2–CH3 bonds decompose completely during the UV-annealing process. These account for the reduced dielectric constant to k = 3.2 from 3.6 and a 21% enhancement of Young's modulus to 7.4 GPa in the SiCxNy films after UV-annealing. Broadband UV-annealing shows promise as a post-treatment method for enhancing the properties of low-k dielectric barrier, SiCxNy films.

Reliability Improvement for Stacked Dielectric with Low-k SiOCH Dielectric and SiCN Barrier by UV-Assisted Thermal Curing

“…Recent studies 15,16 have shown that UV-assisted thermal curing results in changes of the film properties of pristine SiOCH film and SiCN barrier, as summarized in Table I. For the SiCOH film deposited with an organic precursor, UV-assisted thermal curing removes the organic precursor and forms the pores within the film; it also modifies the skeleton structure and enhances film's mechanical properties.…”

“…15 When deposited by a single-source precursor, the SiCN barriers after UV-assisted thermal curing become silicon-rich, associated with a significant decrease in carbon composition. 16 Additionally, UV-assisted thermal curing results in a reduction of film thickness, k value, and density, while Young's modulus is increased due to the enhancement of cross-linking and rearrangement of the film's skeleton structure.…”

Synthesis, solution dynamics and chemical vapour deposition of heteroleptic zinc complexes via ethyl and amide zinc thioureides

“…Carbonitride materials have been deposited from a range of precursors: a tungsten imido precursor was used for the CVD of tungsten carbonitride, WC x N y , 21 titanium and zirconium carbonitride films were deposited from titanium( iv ) and zirconium guanidinate precursors respectively via CVD, 22,23 and silicon carbonitride was deposited via plasma-enhanced (PE)CVD from a carbon rich silazane precursor. 24 Though these precursors do deposit the desired carbonitride materials, imido and guanidinate precursors do not contain direct metal–carbon bonds.…”

Near-Room-Temperature Soft Plasma Pulsed Deposition of SiCxNy from 1,3,5-tri(isopropyl)cyclotrisilazane

“…5 Among its traditional usages, SiCxNy is employed as an inert protective coating and encapsulation layer for systems operating under harsh chemical and thermal environments due to its elevated hardness (≥ 40 GPa), high thermal shock and radiation resistance, efficient oxidation protection, and good thermal and tribological performance. 1,[6][7][8] SiCxNy has also been incorporated into a number of current and emerging applications in copper (Cu)-based multilevel metallization schemes in for integrated circuitry (IC) devices. 9 For example, it is being used as a diffusion barrier against Cu migration into the surrounding low dielectric constant () materials.…”

“…9 For example, it is being used as a diffusion barrier against Cu migration into the surrounding low dielectric constant () materials. 7,10 SiCxNy is also under consideration as a capping layer and etch stop for copper interconnects, either individually or in combination with selective cobalt capping. 11 Additionally, it is currently being explored as a dielectric film for inclusion in metal-oxide-nitride-oxide-silicon (MONOS)-type non-volatile memory devices.…”