Jonathan D. Chapple-Sokol

High Quality Plasma‐Enhanced Chemical Vapor Deposited Silicon Nitride Films

The qualities of plasma-enhanced chemical vapor deposited (PECVD) silicon nitride films can be improved by increasing the deposition temperature. This report compares PECVD silicon nitride films to low pressure chemical vapor deposited (LPCVD) films. The dependence of the film properties on process parameters, specifically power and temperature, are investigated. The stress is shown to shift from tensile to compressive with increasing temperature and power. The deposition rate, uniformity, wet etch rate, index of refraction, composition, stress, hydrogen content, and conformality are considered to evaluate the film properties. Temperature affects the hydrogen content in the films by causing decreased incorporation of N-H containing species whereas the dependence on power is due to changes in the gas-phase precursors. All PECVD film properties, with the exception of conformality, are comparable to those of LPCVD films.

Hydrogen incorporation in silicon nitride films deposited by remote electron‐cyclotron‐resonance chemical vapor deposition

We have studied the incorporation of hydrogen in films of silicon nitride deposited by remote electron‐cyclotron‐resonance chemical vapor deposition using silane (SiH4) as the silicon precursor and both ammonia (NH3) and deuteroammonia (ND3) as nitrogen precursors. Nearly stoichiometric films of silicon nitride, with a refractive index ranging from 1.84 to 2.08, were obtained at substrate temperatures from 50 to 550 °C, microwave powers from 0.5 to 2.5 kW, and NH3 (ND3) to SiH4 flow ratios from 2.5 to 10. The total hydrogen incorporation decreased linearly with increasing temperature from a maximum value of 2×1022 to 6×1021 cm−3. The amount of hydrogen incorporated in the film was independent of the microwave power and the NH3/SiH4 flow ratio, though both variables strongly influenced the hydrogen bonding configuration. The majority of the hydrogen ends up bound to the excess species in the film. Films deposited from deuteroammonia show that 70%–80% of the incorporated hydrogen originates from the ammonia...

Characterization of selective chemical vapor deposited tungsten using SiH4 reduction

The growth rate, resistivity, and selectivity of selective chemical vapor deposition of tungsten using SiH4 reduction of WF6 has been examined as a function of SiH4 partial pressure (PP), WF6 PP, growth temperature, total pressure, average residence time, and fraction of exposed area. The growth rate is proportional to the SiH4 PP, decreases with increased temperature, and decreases with increased exposed area. The deposition rate also decreases slightly as the WF6 to SiH4 ratio increases. With a constant SiH4 PP, the growth rate decreases as the total pressure increases (the SiH4 flow rate is decreased at higher total pressures). The SiH4 conversion efficiency increases as the residence time and fraction of exposed area increase. The resistivity decreases as the growth temperature increases or the deposition rate decreases. The resistance increases with increasing Si and F concentrations in the films. Low temperature residual resistance measurements indicated that the increase in resistance is due to imp...

Applications of computational fluid dynamics for improved performance in chemical‐vapor‐deposition reactors

Engineering models, based on computational fluid dynamics, have been developed and used to improve the performance of two metalorganic chemical‐vapor‐deposition reactors. Though the knowledge of the chemical reactions occurring during film deposition is incomplete, the models provide insight into the reactor’s performance and are useful in guiding reactor modifications. In one reactor, the effect of three gas injector designs on the film thickness uniformity is examined; in a second reactor, the shape and placement of a flow deflector, which redistributes the flow of gas over the wafer surface, is studied. In both cases, comparing the experimental results obtained both before and after the reactor modifications, significant improvements in film thickness uniformity were realized.

Stress migration in a copper - Aluminum hybrid technology

Stress migration (SM) time, temperature and process dependencies are investigated using a highly sensitive tungsten to copper interface combined with “plate-nose” and “mesh-nose” structures to accelerate the SM mechanism. Voids formed below the W via on the nose, and the resistance increases caused by these voids peaked at temperatures of 300-325°C. The effects of several copper line and tungsten via process steps are discussed. Process steps which modulated the Cu surface and Cu to via bottom interface had the largest effects.