Andrew S. Alimonda

Mechanism of SiNxHy deposition from N2–SiH4 plasma

The N2 –SiH4 rf glow‐discharge plasma has been analyzed by line‐of‐sight mass spectrometry of species impinging on the deposition electrode (including N atoms), and properties of SiNx Hy films deposited from this plasma have been examined. At high rf power and low SiH4/N2 gas ratio, most of the SiH4 is consumed by reaction of SiHm radicals with N atoms at the film surface and becomes incorporated into the film. No Si–N precursor species are seen in the plasma. This is in contrast to the NH3–SiH4 plasma, where the Si(NH2)3 radical is the key gas‐phase precursor. If power is insufficient or SiH4 flow is excessive, disilane is formed in the plasma. Under disilane‐free plasma conditions, films slightly N rich with no Si–H bonding and only 11 at. % H (as N–H) can be deposited at high rate (21 nm/min). The film tensile stress characteristic of the NH3 process is absent in the N2 process due to the absence of precursor chemical condensation beneath the growing surface. However, step coverage is much worse in the...

Chemistry of SiO2 Plasma Deposition

The chemistry of SiO 2 deposition from undiluted and He-diluted N 2 O-SiH 4 mixtures was studied by line-of-sight mass spectrometry of plasma species coupled with analysis of film IR absorption and dielectric properties. It was found that if RF power is sufficient to generate an O atom supply well in excess of that needed to convert all of the SiH 4 to SiO 2 , then clean IR spectra and high dielectric strength are obtained independent of dilution. Under these plasma conditions, many gas-phase products of the form Si m H n (OH) were detected

Nano-spring arrays for high density interconnect

A new type of compliant interconnect derived from a thin metal film fabricated with a controlled stress profile is being developed for flip- flop interconnects and probing devices. Interconnections have been demonstrated on lateral pitches as tight as 6 microns. The interconnect is highly elastic and can provide up to hundreds of microns of vertical compliance.

Coupling of radio‐frequency bias power to substrates without direct contact, for application to film deposition with substrate transport

We have demonstrated the coupling of 13.56 MHz rf bias power to an electrically floating substrate platform during aluminum sputter deposition by using an rf‐driven electrode spaced 3 mm away from the back of the platform. This electrode gap and the sputtering plasma sheath in series with it form a capacitive voltage divider, so that the peak rf voltage on the platform is 350 V when that on the electrode is 750 V. This amount of coupling produced enough ion bombardment on the aluminum to result in 23% resputtering and an improvement in film sidewall coverage from 10% to 100%. This noncontact, ‘‘proximity’’ method of substrate biasing should greatly facilitate the coupling of rf power into moving substrates in transport‐type deposition processes.