Effect of Deposition Conditions on Properties of Cu Thin Films Electrodeposited from Pyrophosphate Baths

Effects of current density, electrodeposition temperature and solution pH on properties of Cu thin films electrodeposited from pyrophosphate bath were investigated. Current efficiency was decreased with increasing current density and increased with increasing temperature. But solution pH slightly influenced on current efficiency and current efficiency was measured to be above 90% at both room temperature and 55 degrees C. Residual stress of Cu thin film electrodeposited at room temperature was decreased with increasing current density, while current density reaches to 60 mA/cm(2) or more, stress became close to zero. Cu thin films electrodeposited at 55 o C exhibited the residual stress range of 0 similar to 40 MPa. At room temperature, dendritic surface morphology was observed above the current density of 30 mA/cm(2) and at 55 degrees C, above the current density of 100 mA/cm(2). Cu thin films electrodeposited from bath solution with room temperature and 55 degrees C mainly consisted of (111) peaks. Specially, Cu thin film electrodeposited at 30 mA/cm(2) and 55 degrees C exhibited strong preferred orientation of (111) peaks.