Chemical Repair of Plasma Damaged Porous Ultra Low-κ SiOCH Film Using a Vapor Phase Process

Abstract

A vapor phase based silylation process was used to restore plasma damaged porous ultra low-κ SiOCH dielectric films. The process was carried out with 11 different silylation agents. After the processing of blanked wafers, the restoration performance was analyzed by different analytic techniques such as Fourier infrared and Auger electron spectroscopy as well as contact angle, ellipsometric porosimetry, and mercury probe measurements. Quantum mechanic calculations and practical results suggest three repair chemicals having two reactive groups to be most promising. However, a comparable electrical improvement, i.e., κ-value improvement, was achieved with chemicals having one reactive group. The removal of water during the high temperature silylation process is suggested to be the main contributor to the κ-value improvement. The recovery of the surface free energy inhibits or retards water from returning after the silylation process. The chemicals with two reactive groups providing the highest degree of silylation are found to be most appropriate for ultra low-κ dielectric (ULK) recovery. But, depending on the requirement for ULK restoration (e.g., κ-value, surface recovery, etc.), chemicals having one reactive group can be sufficient as well.

Relationships between chemical structure, mechanical properties and materials processing in nanopatterned organosilicate fins

“…The details of the silylation treatment are described elsewhere [37–38]. Additional samples completed a metallization process flow that filled the voids between the organosilicate fins with Cu.…”

“…After completion of fin formation, some samples were exposed to a standard silylation treatment in an attempt to restore some of the terminal organic groups removed from the nanoporous organosilicate by the patterning process. The details of the silylation treatment are described elsewhere [ 37 – 38 ]. Additional samples completed a metallization process flow that filled the voids between the organosilicate fins with Cu.…”

“…The oscillation amplitude of the probe at this frequency was then plotted versus the wavelength of the QCL to generate spectra. All experimental data were collected with the AFM probe in the contact mode using Analysis Studio software (Version 3.7, Anasys Instruments, Santa Barbara, CA) [ 37 ].…”

Low‐kMaterials: Recent Advances

“…Here, the difficulty lies in the delivery of these reagents in order to maximize the penetration into the porous dielectric resin. Although solvent mediated treatments have been proposed, only supercritical CO 2 (SCO2) or gas-phase treatments are of practical value [120][121][122]. Gas-phase silylation is particularly attractive since this restoration process uses a neat reagent at elevated temperatures, greatly amplifying the reactivity of the nonhalogen containing candidates.…”

Theoretical investigation of in situ k-restore processes for damaged ultra-low-k dielectrics

“…However, the size of the precursors (6-9 Å) prevents them from diffusing into deeper regions of the damaged ULK material. Therefore, the repair via silylation is limited to the surface [7].…”