EFM and ESD in photolithography by cavity QED

Abstract

Sub-micron gaps in photolithography are known to undergo electrostatic discharge (ESD) under applied voltage or fields. Recently, reticle failure caused by electric field migration (EFM) of metallic ions has surfaced as a serious problem. Under fields induced from production equipment, the glass substrate between electrodes is coated with metal cations that reduce the gap resistance leading to ESD. Photoemission may explain reticle failures provided a source of electromagnetic (EM) radiation at vacuum ultraviolet (VUV) frequencies is available to produce metal cations. At ambient temperature, the only available source of EM radiation is the thermal kT energy of atoms in the gap surfaces emitted at infrared (IR) frequencies, but lacks the Planck energy to liberate electrons from the metal electrodes. Here the VUV radiation is proposed produced in cracks that form as the metal layer separates from the glass in the fabrication process. By treating the gap between the metal and glass as a quantum electrodynamics (QED) cavity, the IR radiation in gap surfaces is induced to undergo frequency up-conversion to the VUV that by the photoelectric effect produces metal cations, the process called cavity QED induced EM radiation. The metal cations migrate under fields to coat the glass leading to ESD.