Near‐Surface Damage and Contamination after  CF 4 /  H 2 Reactive Ion Etching of Si

Abstract

Silicon surfaces which had been exposed to CF4/40%H2 reactive ion etching have been characterized by x‐ray photoelectron emission spectroscopy, He ion channeling, H profiling, and Raman scattering techniques. Plasma exposure of a clean Si surface leads to the deposition of a thin (∼30–50Å thick) C,F containing film. The near‐surface region (∼30–50Å) of the Si substrate is heavily disordered (“amorphized”), as found by ion channeling and Raman scattering. A modified, less damaged Si region extends from about 30–50Å from the surface to a depth in excess of 250Å. This layer contains a high concentration (∼5 atom percent) of H as shown by hydrogen profiling techniques. From the observation of Si‐H and normalSi‐H2 vibrational modes by Raman scattering, it has been shown that the H is bonded to the Si lattice. In ion scattering, the extended modified Si layer appears to cause a strongly enhanced background in the energy spectra. Results of Monte Carlo range calculations are reported and compared with the damage depth found experimentally.

X-ray photoelectron spectroscopy analyses of silicon dioxide contact holes etched in a magnetically enhanced reactive ion etching reactor

“…The increase of the FHWM of the Si 2p peak measured by XPS has shown the presence of an amorphized silicon layer ͑layer 3͒ induced by the highly energetic ion bombardment of the RIE plasma. 13,15,16 The presence of carbon bonded to silicon below the fluorocarbon polymer film was also demonstrated through the presence of Si-C bonds located at 101.3 eV and the presence of an additional component in the C 1s spectrum, located at 283.4 eV. 13 In other studies, XPS experiments have been conducted on blanket SiO 2 or Si surfaces under plasma operating conditions employing lower level of rf source power than those used in this work.…”

Deep etch-induced damage during ion-assisted chemical etching of sputtered indium–zinc–oxide films in Ar/CH4/H2 plasmas

“…Deep penetration of H atoms was also demonstrated in other materials for similar plasma etching conditions (see for example Refs. [29][30][31][32]). This very high diffusivity of hydrogen atoms at such low temperatures results from the fact that H transport in larger host atom matrixes is driven by a direct interstitial mechanism for which the activation energy is relatively low [33,34].…”

Suppression of 193-nm photoresist deformation by H2 addition to fluorocarbon plasma in via-hole etching

“…This polymer achieves a high selectivity to masks such as photoresists and underlayers such as Si substrates [12][13][14][15][16][17][18]. Furthermore, H 2 addition leads to the damage of a deep layer of the Si substrate [19,20]. However, its influence on photoresist deformation is not entirely clear and is evaluated in this section.…”