Testing system for groove geometry of CD-R substrates

We introduce a homemade testing system for groove geometry of CD-R substrates by measuring diffraction orders. This testing is of particular importance in CD-R disc manufacture process because the results fed back from the testing can be used to help optimizing recording, developing, metalizing, electroplating and replicating processes. Even if the width and depth of groove are not accurately obtained by this system, it is also valuable in CD-R disc manufacturing process because the system is simple, sensitive, quick and non- destructive, and can be well-used to judge the quality of substrates. The results of the same sample tested by our system and an AFM microscope are presented.