High-power fast-atom beam source and its application to dry etching

Abstract

We have developed a new high-power fast-atom beam (FAB) source by modifying a McIlraith-type ion source. The beam current density emitted from a source with an electromagnet and multiaperture grid is about ten times higher (up to 1 mA/cm2) than that emitted from a conventional source. Silicon dioxide can therefore be etched at 60 nm/min when CF4 gas is used, or about six times faster than by using a conventional source with the same discharge current. The beam neutralization coefficient of the new FAB source is nearly 100%. We have used this FAB source to etch Si, SiO2, GaAs, and other compound materials. We could easily etch an anisotropic profile (nearly vertical with an aspect ratio of more than 10 for a 0.6 μm L&S pattern), etch at a high rate (0.3–0.5 μm/min), and etch with high selectivity (GaAs:resist =30:1). We also fabricated a SiO2 fine pattern in 0.6 μm L&S by using CF4 reactive-fast-atom beam etching. The uniformity of the etch depth is about ±5% over a 4-in. wafer. Surface radiation damage (total oxide charge) caused by FAB bombardment of the SiO2/Si structure is very close to that of reference (not etched) samples. This damage is significantly less than that caused by ion beam bombardment under almost the same radiation conditions.

Low damage etching method of low-k material with a neutral beam for interlayer dielectric of semiconductor device

“…Previously, a neutral beam was used in the etching of various materials and, by eliminating the charge of the energetic ions bombarding the surface of the materials, the plasma damage could be reduced. 20,21 In this study, in the etching of low-k materials, beam etching techniques such as ion/neutral beams have also been applied and the effects of beam etching on the characteristics of etched low-k material such as the chemical binding states, contaminated layer thickness, dielectric constants, etc., have been investigated and compared with those obtained with conventional inductively coupled plasma (ICP) etching techniques.…”

Optical properties of DLC films deposited by the saddle field fast atom neutral beam source

“…A fast atom beam defined as energetic neutral particles ranging in energy from a few electron volts to several thousand electron volts [1,2]. The development of the saddle field fast atom beam source allows material processing of amorphous thin films in a very uncomplicated manner.…”

Emerging Plasma Nanotechnology

“…The interface state density due to defect One promising approach to resolving these issues is the use of neutral beam process technology. [6][7][8][9][10][11][12][13][14][15][16][17][18] The neutral beam atomic layer process reduces the incidence of charged particles and UV photon radiation from the plasma onto the substrate so that the substrate is exposed only to the energycontrolled neutral beam. In other words, it is possible to precisely control the kinetic energy of the neutral beam by means of the ion acceleration energy obtained with the applied electric field before neutralization.…”

“…in order to realize the optimum chemistry according to the material. [19][20][21] In this paper, we review the neutral beam generation technique 7,8) developed by S. Samukawa and investigate research on its application to atomic layer etching (ALE) [19][20][21] and deposition (ALD) 22,23) .…”