A process for forming a damascene structure includes depositing a bilayer comprising a first dielectric layer and a second dielectric layer onto a substrate, wherein the first layer has a dielectric constant higher than the second layer, and wherein the second layer is selected from a low k dielectric material comprising Si, C, O and H. The method includes the step of gradually adjusting the de-emphasis of the signal transmitted from the data transmitting and receiving device according to the setting value thereof. The test data are analyzed by a central data processing unit connected to the computer through a network, and the result is distributed to authorized users through the network.