Hydrogen plasma effects on ultralow-k porous SiCOH dielectrics

Abstract

This study investigated the interactions of hydrogen plasmas with ultralow-k porous SiCOH (pSiCOH) films and their dependency on the values of the original dielectric constant, porogen used for the preparation of films, and substrate temperature during the plasma treatment. pSiCOH films of similar dielectric constants have been prepared by plasma-enhanced chemical-vapor deposition using an identical SiCOH skeleton precursor, but with two different organic porogens. The films exposed to the hydrogen plasmas have been characterized by optical techniques, shrinkage characterization, and electrical measurements. It was found that the hydrogen plasma modifies the structure of pSiCOH’s oxide skeleton and reduces the concentration of the Si–(CH3)1 bonds, resulting in an increase of the dielectric constant. The degree of modification, for films prepared from the same precursors, is larger for films with lower dielectric constants (k) and is affected by the porogen used to prepare films with similar k values.

Effects of He (90%)/H2 (10%) plasma treatment on electric properties of low dielectric constant SiCOH films

“…For example, the activated silyl sites are generated from breaking Si-C, Si-H, and SiSi bonds by active hydrogen species in the plasma. These are then available to react with oxygen to generate Si-O-Si structures [11]. It is thought that high contents of Si-O bond that has high thermochemical energy [10] in the low-k SiCOH films can contribute to decrease of leakage current pass.…”

Effects of He Plasma Pretreatment on Low-k Damage during Cu Surface Cleaning with NH[sub 3] Plasma

“…Some groups report that these plasmas have no effect on the SiOC:H film, 4,19,20,22 others report that it enhances the dielectric properties, 24 and yet others indicate that H 2 plasmas cause significant damage. 3,21 The replacement of CH 3 17,19,20 However, certain additional activation provided, for instance, by ion radiation and UV light makes these reactions possible, causing the difficulty to realize damage-free processes in the reactive ion etching ͑RIE͒ condition. 19,25 For instance, Matshushita et al 19 showed that the damage during the H 2 plasma treatment depends on the type of chamber used.…”

“…The SiOC:H film contains bonds local- ized at 1200 − 1000 cm −1 from C-O-C or Si-O-C asymmetric stretching vibrations. 21 However, the identification is difficult because they overlap with the Si-O-Si asymmetric stretching band. After the NH 3 plasma treatment, a clear shift to higher wavenumbers of the Si-O-Si absorption band is observed.…”

Characterization and versatile applications of low hydrogen content SiOCN grown by plasma-enhanced chemical vapor deposition

“…For example, hydrogen incorporation is known to decrease dielectric constant, breakdown strength, hardness, refractive index, and increase leakage current, to name a few. [10][11][12] A post-deposition anneal at increased temperatures is a common method to decrease the hydrogen concentration within a PECVD grown film. However, to maintain the integrity of the coating and the possible substrates which can be used, this method is undesirable.…”