We examined the effect of barrier thickness on Cu grain orientation control. We demonstrate that 5 nm thick HfN films which showed excellent barrier properties in our previous study are applicable to the underlayer for Cu grain orientation control. The strong (111)-oriented Cu layer is enhanced by using the HfN barrier with a 5 nm thickness. The obtained results bring about the compatibility of the high performance barrier with a suitable underlayer to obtain the highly-oriented Cu layer. These results are also valid for the development of barrier or underlayer materials for use in Si-LSI and three-dimensional LSI technology.