Papers by Keyword: Plasma Damage

Abstract: A rapid repair process of plasma damaged SiCOH in combination with post-etch residue removal has been developed. The carbon depletion layer caused by plasma dry etching was repaired by subsequent surface modifying SAM treatment, which resulted in replenishment of carbon not only on the surface but also a few nm toward the bulk. This repairing technique provides a high-quality hydrophobic surface under conditions of low temperature and short process time. In addition, the SAM layer can be expected to act as an adhesion promotor with metal materials.

Abstract: Porous ultra low constant materials (ULK) for isolation within the interconnect system of integrated circuits are a promising approach to reduce crosstalk and RC-delays due to shrinking feature sizes [1]. Due to their porosity and the integration of carbon rich species like methyl groups into the Si-O-Si backbone of currently fabricated PECVD SiCOH dielectrics those materials are highly sensible towards plasma processing, e.g. dry etching or resist stripping [2]. Metal hard mask approaches, e.g. using TiN hard masks are widely used to prevent the resist stripping plasma directly attacking the low-k material [3]. To reduce further plasma damage like carbon depletion and formation of polar silanol groups the development of less aggressive etching processes is in the focus of research and development activities. Nevertheless dry etching will attack the sidewalls and cause a material degradation. That is why repair processes, mainly based on silylation, are considered to follow the patterning step to reintegrate carbon rich species and to recover the dielectric’s properties [3]. Subsequently to dry etching and repairing the dielectric the wet chemical plasma etch residue removal process is performed. Besides material compatibility and effectiveness in residue removal the wetting behavior of the applied cleaning solutions towards the surface which has to be cleaned is crucial, especially looking on wetting issues like the incomplete wetting of very small via holes or pattern collapse. In this study we investigate in which way different silylation based repair processing regimes are affecting the wettability of the dielectric by water based cleaning solutions using contact angle based surface energy calculations.

Abstract: Self-assembled monolayers (SAMs) deposition is being recently explored to help sealing the pores of a k=2.0 material. In order to enable a covalent chemical low-k surface functionalization by SAMs, a hydroxyl groups density as high as 1 to 2.5 OH groups/nm² is required. This surface modification must be carefully controlled to confine the k below 10%. In this paper, the effects of plasma temperature, time and power on the SAMs deposition and plasma-induced damage are investigated. The main findings are that there is always a trade-off between surface hydroxyl groups density and bulk damage. A thick modified layer allows the SAM molecules to penetrate inside the pores which results in a decreased porosity and an increased k value with respect to correspondent plasma-treated pristine substrates.

Abstract: In this study, the compatibility of "HF-Based" cleaning with porous low-k integration, and “pore-sealing” approach was investigated, and specific attention was paid to ultra low-k porosity evolution. We also tried to demonstrate if "k-recovery" could be achieved by thinning the modified surface layer in the pattern trench walls (plasma damaged layer), for 65nm and 45 nm design rules.

Abstract: Recently, plasma-less gaseous etching processes have attracted attention for their interesting etching properties. Previously, we reported on the etching properties of theses processes for various kinds of oxides and revealed that they reduce the etch rate of the chemical-vapor-deposited (CVD) oxides more than the conventional wet etching process does [1]. Our results also revealed that depressions called divots in the CVD oxide of the shallow trench isolation (STI) became smaller in size by substituting a plasma-less gaseous etching process for the conventional wet etching process. In semiconductor manufacturing, many processes are used to remove oxides damaged during ion implantation or reactive ion etching on the device surface. Therefore, it is very important to understand the etching properties of plasma-less gaseous etching processes for damaged oxides as well as those for other kinds of oxides. In this report, we evaluate the etching properties of one particular plasma-less gaseous etching process for oxide films damaged during the ion implantation process under various conditions and discuss the mechanism of interesting etching properties for the damaged oxides.