Azole layers, such as benzotriazole and imidazole, on Cu surfaces have
long been known to protect the copper surfaces from corrosion. In the
fabrication of printed circuit boards, azole layers can protect the s
olderability of Cu surfaces by limiting the oxidation of the Cu. The t
hermal stability of imidazole and 5-methylbenzimidazole layers on Cu s
urfaces under vacuum, nitrogen, and air have been studied using Fourie
r transform infrared spectroscopy and x-ray photoelectron spectroscopy
. These films are much more stable under nitrogen and vacuum than unde
r air, and the decomposition mechanisms of the films are different und
er different atmospheres.