Flowable Chemical Vapor Deposition of Lightly Porous Low k SiCOH Dielectrics—Remote Plasma Deposition Processing, Film Analysis and Gap-Fill Application in Nano Device Fabrication

Low k and porous low k SiCOH dielectrics have been implemented in Cu_Low k metallization of integrated circuits for high-performance nanoelectronic CMOS devices for more than two decades (1). For the last several years, the low k SiCOH dielectric plasma deposition process normally involves the deposition of blanket planar film for using copper damascene interconnects fabrication. Due to the low conformality of plasma deposited in SiCOH film, the dielectric deposition process is normally limited to blanket planar film deposition. For the new generation of 3-D nano device fabrication in which both logic and memory are integrated into a single chip, there is a need to develop an advanced low-temperature low k SiCOH film that enables advanced high aspect ratio gap fill properties. In recent a study, we briefly described an advanced development of the Fully Aligned Via (FAV) process using flowable chemical vapor deposition (FCVD) low k SiCOH and laser/nitrogen implanted FCVD SiCOH film capable of filling recess gaps with self-planarization (2,3) with decent device performance. This inventive FAV approach enables the advanced fabrication of robust 5 nm node device structure fabrication. The advanced remote plasma porous low k p-SiCOH with post UV treatment dielectric, robust reliability, and fabrication integration robustness is needed for the critical and top requirements in the device’s reliability and performance.

This paper presents the comprehensive deposition processes, post-deposition UV cure, and film analysis by advanced nuclear reaction analysis, FTIR, RBS, and MIS electrical measurement to optimize the film’s stability and composition. The flowable film was engineered for advanced gap-fill application of low k porous SiCOH that can achieve high aspect ratio gap-fill (>10:1 aspect ratio) with low dielectric constant (k<= 2.75) while still maintaining about the same excellent electrical, mechanical, fabrication integration robustness and reliability of conventional plasma CVD SiCOH film. The optimal FCVD process was developed for manufacturing worthy 300 mm CVD system to deposit SiCOH using organosilicon precursors with remote O2 plasma at low deposition temperature (80-100C) and the UV cure at higher temperature (385-400C).

This FCVD SiCOH film with varying compositions was engineered to create a good low k dielectric capable of excellent high aspect ratio nanostructure gap fill performance but with a lower dielectric constant with good mechanical properties, interface adhesion, and excellent electrical properties.

REFERENCES

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