Plasma Passivation of Siloxane-Based Low-k Polymeric Films

Abstract

This study investigates how the chemistry of the single (O 2 , N 2 , and H 2 ) and mixed gas sources (N 2 /H 2 ), and the plasma-related operating conditions affects etching and ͑or͒ passivation of siloxane-based polymer ͑HOSP͒ films. Plasmas generated using inadequate power sources and an H 2 -dominating chemistry induced the breakdown of carbonaceous species and over-crosslinking of the HOSP films, sharply degrading the films' dielectric constant (k) and insulating characteristics. However, properly adjusting the power/energy deposition and shifting the mixed gas toward the N 2 -dominant regime generated an N 2 /H 2 plasma that acted positively to protect the films from O 2 plasma damage and retard copper diffusion during thermal annealing. X-ray photoelectron and absorption spectroscopies, along with depth-profiling secondary ion mass analysis, indicated that the passivation effect was due to the formation of a surface nitride-based layer that contained implanted nitrogen atoms of various chemical bonding states including Si-N, C-N, and O-N. The synergistic effect of the mixed N 2 /H 2 gases in the plasma passivation of HOSP films is discussed in terms of previous studies of plasma etching of low-k films and ion nitriding.

Chemical Properties, Structural Properties, and Energy Storage Applications of Prussian Blue Analogues

“…Various PBAs have been prepared by the precipitation method, in which a solution containing metal-ion salts is mixed with a solution of ferrocyanide ligands to produce the PBAs. [21][22][23]26,27,29,32,[35][36][37]39,41,56,67,[75][76][77] The obtained PBAs present a random morphology owing to the fast reaction between the ligands and the metal ions, as shown in Figure 2a. [41,75] To control the morphology of PBAs prepared by the precipitation method, coordination agents are utilized to slow the reaction rates.…”

Hydrogen plasma effects on ultralow-k porous SiCOH dielectrics

“…Furthermore, unless the plasma conditions are adjusted properly, a hydrogen-dominated chemistry can breakdown carbonaceous species, increase the crosslinking in the films, and increase their dielectric constant. 8,9 The goal of this work was to study in more detail the effects of hydrogen plasma on the properties of porous SiCOH ͑pSiCOH͒ films prepared by PECVD and the dependency of these effects on the substrate temperature and bias during the plasma treatment and on the precursors used for preparing the films.…”

Self-Aligned Deposition Process for Ultrathin Electroless Barriers and Copper Films on Low-k Dielectric Films

“…Now considering the role of hydrogen peroxide, hydrogen peroxide in the SC-1 solution is a strong oxidizing agent, transforming itself into an intermediate phase of hydroxo radical ͑OH•͒, 23 and could be ultimately reduced into hydroxide ions (OH Ϫ ). Additionally, the H 2 ͑or O 2 ) plasma is highly efficient in opening up the Si-O caged structure and eliminating methyl side-chain groups of HOSP™ films, 17 primarily via a radical reaction mechanism. 24,25 This reaction leaves behind Si dangling bonds ͑Si•͒ and doubletbonded Si-O ligands, subsequently reacting with the dominant OH•, OH Ϫ , and H 2 O in the SC-1 solution, and converting themselves into surface silanol groups ͑Si-OH͒.…”

“…Before going through the whole steps of the electrochemical processing described below, some films were pretreated with a plasma generated by either O 2 or N 2 /H 2 mixture under an optimal condition described in detail elsewhere. 17 The so-called SC-1 18 or ammonia (NH 3 ) contained aqueous solutions were then employed to modify surfaces of the films in an attempt to obtain negative charges on the dielectric films. The negatively charged sites thus could attract nickel ions by immersing the sample films in an aqueous solution of nickel salt.…”