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Fluorinated Oxynitride Films Prepared by Temperature-Difference Deposition Method Using the Aqueous Solution of Hydrofluorosilicic Acid and Ammonium HydroxideShieh, Wu-Hung 11 July 2002 (has links)
The advantages of LPD method, low temperature process, low cost, conformal growth (good step coverage), selective growth and inexpensive deposition system make the method of LPD versatile in IC fabrication. LPD-SiOF is a potential method to replace traditional method of SiOF deposition. But, some drawbacks, including slightly low dielectric constant and poor performance of J-E relationship, still exist in LPD-SiOF process. In order to improve these shortcomings, with incorporating NH4OH into the LPD solution in this experiment, the SiOF:N film with high quality and low dielectric constant can be grown on Si by the TD-LPD method.
In this study, the growth rate can be controlled well within 90~550 Å/h corresponding to the NH4OH concentration range of 0.1~0.8 M at the temperature range of 23~40 ¢XC. As TD-LPD-SiOF:N film deposited with 0.8 M NH4OH incorporation, the refractive index for can be kept at a constant 1.431 and the P-etch rate can be kept between 18.3 and 19.2 Å/s during the deposition temperature changes.
The best experimental condition is found that incorporating 0.8 M NH4OH will get good results. If the concentration of 0.8 M is higher or lower than 0.8 M, the electrical characteristic will become poor.
A model for TD-LPD-SiOF:N deposition mechanism is proposed. From the analysis of SIMS depth profile, the deposited film can be suggested that it is a combination of N-less LPD-SiOF film and N-rich accumulated interfacial layer. The properties of N-rich accumulated layer at the interface show the least effective oxide charges and lowest leakage current density.
As the thickness of TD-LPD-SiOF:N film is 800 Å, the film has the best electrical characteristic. When the thickness is below or above 800 Å, all the properties become poor. TD-LPD-SiOF:N film deposited at 40 ¢XC with 0.8 M NH4OH incorporation with a thickness of 800 Å has the best physical, chemical, electrical properties. The F content for deposited film can reach 9.8 atom %. The dielectric constant can drop to about 3.07.
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The Electrical Properties of Liquid-Phase Deposited SiOF Films with Annealing TreatmentChang, Shu-Ming 10 July 2003 (has links)
With increasing integration density of very large scale integrated (VLSI) devices, multilevel metallization technology is becoming more important than it used to be. In advanced logic devices, the interlayer dielectrics have increased to four or five layers. Silicon oxide films are used as interlayer film. One candidate for making interlayer film with a low dielectric constant is F-doped Silicon oxide (SiOF). Such films have a low dielectric constant and that moisture absorption is the main drawback in using this material. For this reason, we intend to dehydrate the SiOF films by thermal annealing treatment. It could improve the electrical properties of oxide films and obtain a reliable film with lower dielectric constant.
This is our purpose in this paper to explore the electrical and chemical properties of LPD-SiOF films with annealing treatment. The chemical and electrical properties can be controlled well within 250 ~ 450 ¢J annealing treatment. The LPD-SiOF film deposited at 40 ¢J with 0.8 M NH4OH incorporation and 350 ¢J annealing treatment obtain the best electrical results. The dielectric constant can drop to about 3.2, and the leakage current density can be improved to about 1¡Ñ10-7 A/cm2 under 1.5 MV/cm. Results of this study demonstrate that the SiOF films prepared by LPD with NH4OH incorporation followed by annealing treatment is suitable for IMD application.
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