The outgassing behavior and mechanical properties of polysiloxane based and phosphorus doped silicate based films as planarization candidates for device processing were evaluated using various analytical techniques. After curing between 370 °C and 450 °C, a high temperature rebake above 410 °C caused twice the weight loss in polysiloxane based films as in silicate films. This means that further outgassing, which could occur to a greater degree from polysiloxane than from silicate, could lead to a more probable blistering within the interlayer of the sandwiched spin-on-glass (SOG) during subsequent thermal processing. However, a well-cured polysiloxane would be a better candidate for planarization applications because the film was found to absorb less moisture and had lower stress than the silicate. Due to high silanol content and high porosity in silicate, it was found to absorb six times more water than polysiloxane. When water evolved, significantly higher stress levels were observed in silicate than in polysiloxane during thermal cycle tests. Infrared spectroscopic analysis revealed that polysiloxane contained Si–O–CH3 moiety, which rendered the film flexible, while silicate contained near-stoichiometric SiO2 bonds, which made for a more rigid and dense structure. This difference in the film structures translated to three times higher stress in silicate than in polysiloxane. During device processing, it was seen that silicate films were more prone to cracking than polysiloxane films. The components of the outgassing materials were either volatile organic species from residual solvents not completely burned out during cure, or carbon dioxide and water vapor as by-products from further cure. Gas chromatography indicated that both types of films contained volatile organic residues when cured at 370 °C. However, at 410 °C, volatile organic species were present in the polysiloxane but not in the silicate. A 30 to 60 min cure at temperature greater than 410 °C was then found to adequately cure polysiloxane. It was concluded that a “well cured” polysiloxane based spin-on-glass (SOG) would be more suitable than a silicate based SOG for planarization application.

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Thin silicon nitride films ͑less than 20 nm͒ deposited on ͑100͒ silicon substrates via low pressure chemical vapor deposition ͑LPCVD͒ at three temperatures ͑730, 760, and 825°C͒ were analyzed by spectroscopic ellipsometry ͑SE͒, attenuated total reflection ͑ATR͒, and other tools. Films appeared to have similar optical bandgaps ͑ϳ5 eV͒, and the values decreased slightly with the higher deposition temperature. Second ionic mass spectroscopy results showed that a similar amount of oxygen exists in the interface between silicon and silicon nitride. ATR spectra showed no sign of Si-H bonds and decreasing N-H bonds at higher deposition temperature in the thin films. The electrical properties of the films are also discussed.Silicon nitride films have been widely used in very large scale integration ͑VLSI͒ technologies, such as diffusion mask, passivation, antireflection coatings, and gate dielectrics. 1-4 Various processing methods of silicon nitride films were reported, such as thermal nitridation, 5 atmospheric pressure chemical vapor deposition ͑CVD͒, 6 plasma-enhanced CVD ͑PECVD͒, 7 hot wall CVD ͑HWCVD͒, 8 and low pressure CVD ͑LPCVD͒. 9 Among the fabrication techniques, LPCVD is commonly chosen. Even though LPCVD nitride films cannot be used for gate dielectrics due to their poor interface quality and high bulk trap density, they are widely chosen for applications such as diffusion mask, nitride spacers, etc. We studied the LPCVD silicon nitride thin films deposited by using a mixture of dichlorosilane ͑DCS͒ and ammonia (NH 3 ) with nitrogen as dilute at three temperatures in a conventional batch reactor.The purpose of this work was to analyze the optical properties of thin to ultrathin ͑below 10 nm͒ silicon nitride films via spectroscopic ellipsometry ͑SE͒ analysis and directly study the bond structure ͑es-pecially bonds with hydrogen such as Si-H and N-H͒ of the films by attenuated total reflection ͑ATR͒. SE is a nondestructive optical technique used to determine the optical properties of substrates and thin films based on measuring the polarization ellipse of a light beam reflected off a sample at a given angle. From this data, the complex index of refraction and film thickness can be determined using a computer model fit. ATR provides a way of directly analyzing very thin films with much higher sensitivity than normal Fourier transform infrared ͑FTIR͒ analysis. A schematic plot of ATR measurement is shown in Fig. 1. The infrared radiation signal penetrated into the monolayer film only once during the measurement. Typical thickness for normal FTIR analysis is equal or larger than 1000 Å to get desirable signal noise ratio. However, the actually used films in electronic devices may not necessarily meet this thickness requirement. In this work, all the films' thicknesses are less than 20 nm. By using ATR and Woollam SE analysis we can directly study the optical properties of these ultrathin nitride films. Other films properties like electrical data were also discussed. ExperimentalSingle crystal ͑100͒ p-type silico...

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