Specular electron scattering at the surface of metallic thin films is an important phenomenon for a class of magnetic multilayers known as giant magnetoresistance (GMR) spin valves. In the very best GMR spin valves, a significant part of the GMR effect is attributable to specular electron scattering. We have investigated the importance of specular electron scattering by developing surface-modification techniques that produce diffuse electron scattering. We have used these techniques to investigate specular electron scattering in GMR spin valves and in pure metals. Some of the largest effects are found in Au films. It is noted that specular electron scattering will be a highly desirable property in future generations of microelectronic interconnects as the feature size approaches the mean free path of the conduction electrons. In order to meet the Semiconductor Industry Association Roadmap requirements for interconnect resistivity, interconnects with highly specular surfaces must be developed.