Manufacturability of advanced laser texture designs [magnetic disks]

A model has been established to describe the relationship between laser texture bump height and the offset from the focal plane. Experiments have been carried out to quantify model parameters. A smaller bump diameter design provides improved stiction performance using an optimized bump spacing arrangement. However, smaller bump diameter corresponds to smaller depth of focus. Since the bump height is highest when the disk surface is at the focal plane and since substrate surfaces normally have a runout of about 15 to 40 μm, the minimum bump height in a batch of disks will decrease with lower bump diameter or larger defocus offset distance. Using the bump height defocus model combined with our stiction model, we found that a bump diameter less than a critical value will adversely affect the stiction performance