Embodiments of the present invention relate to classifying pages of an electronic document, such as a scanned book page. The wet friction material has a substrate having a surface and a very superficial layer. The present invention also provides a method of fabricating such a semiconductor structure. With this arrangement, it is possible to provide a wiring material allowing use of a larger variety of materials, while also ensuring low resistance of wiring and improvement of adhesion between the wiring and the substrate.