 Image Number 17 for United States Patent #7497916.
When a separation layer is formed using a stamper between a substrate and the stamper on a thick substrate, on the surface of which a rewritable recording multilayer film provided with signal guide grooves or pits and the signal guide grooves or pits are transferred from the stamper to the surface, variations in the thickness of the separation layer are produced due to unevenness of the distance between the stamper and the substrate.The surface of the kth signal recording layer of the kth signal substrate is shaped parallel to the surface with the guide grooves and pits of the (k-1)th signal recording layer on the (k-1)th stamper, a (k-1)th separation layer is formed between the two and then the (k-1)th stamper is peeled off. The distance between the surface with the guide grooves and pits of the (k-1)th signal recording layer and the kth signal recording layer becomes uniform, and therefore the thickness of the (k-1)th separation layer can be kept uniform.
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