Investigation of Reactive‐Ion‐Etching‐Related Fluorocarbon Film Deposition onto Silicon and a New Method for Surface Residue Removal

Abstract

The effects of SiO2 reactive ion etching (RIE) in CFJ40% H2 on the surface properties of the underlying Si substrate have been studied by x-ray photoemission and He ion scattering/channeling techniques. The two major modifications of the Si near-surface region are: (i) A disordered Si layer which contains -1-2 • 10 TM displaced Si atoms/cm 2, the degree of the disorder depending on the plasma exposure time of the Si substrate. (ii) The presence of a -30~ thick film containing carbon and fluorine. The glow discharge deposited C,F-film exhibits a complex carbon ls x-ray photoemission spectrum and displays at least five bonding states of carbon. They are (in the order of decreasing intensity) C-C and/or C-H, C-CFx, CF, CF3, and CF2 type bonding. A new method for Si substrate post-RIE cleaning is described. The method accomplishes the removal of most RIE related surface residues and the removal of Si lattice disorder in one processing step. The efficacy of the method has been verified by ion scattering and x-ray photoemission measurements.

Vibrational electron energy loss studies of surface processes on Si(111)7×7 and vitreous SiO2 ion-mediated in CF4 and CH2F2

“…In spite of the extensive studies on the effects of ion bombardment on silicon [7][8][9]11], the interactions of fluorocarbon ions with Si remain poorly understood, especially for bombardment energy below 100 eV. Many surface diagnostic tools including X-ray photoelectron spectroscopy, Auger electron spectroscopy (AES), and Fourier transform infrared spectroscopy have been used to investigate the surface processes induced by ion irradiation of halocarbons [8,[12][13][14][15]. Recently, we have investigated the surface products on clean and oxidized surfaces of Si(1 1 1)7 Â 7 generated by ion irradiation in CF 4 at 50 eV impact energy by using the more surface-sensitive vibrational EELS technique [16].…”

Dry Etching of Electronic Oxides, Polymers, and Semiconductors

“…Substrate and oxide damage, and the presence of etch residues are all deleterious effects of dry etching 58–63. Typical ion energies fall in the range of 50–700 eV with fluxes on the order of 10 15 ions · cm −2 .…”

Characteristics and Recovery of SI Surfaces Plasma Etching in CHF3 / C2F6

“…Various fluorocarbon plasma treatments and their interaction with the Si or Si02 surfaces have been analyzed in recent years [3][4][5]. For removal of silicon surface residue resulting from the RIE, heat treatment in dry oxygen or rapid thermal anneal treatment have been studied [6,7]. Although oxidizing process by exposing to an 02 plasma is used for removing the surface residues [8], this approach presents a problem of the silicon lattice damage and trapped impurities.…”