US Patent 7491574 Reducing oxidation of phase change memory electrodes

A phase change memory may be formed in a way which reduces oxygen infiltration through a chalcogenide layer overlying a lower electrode. Such infiltration may cause oxidation of the lower electrode which adversely affects performance. In one such embodiment, an etch through an overlying upper electrode layer may be stopped before reaching a layer which overlies said chalcogenide layer. Then, photoresist used for such etching may be utilized in a high temperature oxygen plasma. Only after such plasma treatment has been completed is that overlying layer removed, which ultimately exposes the chalcogenide.