Experimental study of the transcription of minute width grooves by injection molding (II)

In the injection molding of substrates for optical discs, precise transcription of the pits and grooves is imperative. In particular, for high density optical discs, molding transcription of minute grooves with widths on the sub-micron level is required. In this study, in order to quantitatively clarify the relationship between the molding conditions, molding resins, and the transcription, the transcription of minute rectangular grooves (width 0.55 μm, depth 70 nm) by injection molding was studied. Polycarbonate, amorphous polyolefin, and Polymethylmethacryrate resins were employed. A transcription model for the minute groove utilizing the concept of the equivalent thickness of the vitrified layer was introduced, and the relationships between the molding conditions, resin properties, and the transcription heights were verified. Among these resins, amorphous polyolefin, which has the lowest elastic modulus, indicated the highest transcribability.