Feasibility of Etching Studies on BCN Thin Films

Abstract

Investigation of wet chemical etching Boron carbon nitride (BCN) thin films deposited by dual magnetron sputtering of B 4 C (DC) and BN (RF) targets was conducted. BCN, a low-k dielectric material, is a potential candidate as inter-layer dielectric (ILD) in VLSI process. A common aluminum etchant consisting of phosphoric acid (H 3 PO 4), nitric acid (HNO 3) and acetic acid (CH 3 COOH) was tested for its feasibility as a good etchant for BCN thin films. The etching studies were performed on BCN films that were deposited at room temperature, 200 • C and 300 • C as a function of various N 2 /Ar gas flow ratios in an rf sputtering technique. It was found that the film deposited at higher temperatures shows lower etching rate trends. Activation energies (E a) were calculated for each N 2 /Ar gas flow ratio with the help of Arrhenius plots and compared with respect to elemental compositions of the films.