Process considerations for critical features in high areal density thin film magnetoresistive heads: A review

Today, magnetic recording areal densities using magnetoresistive (MR) head technology are approaching 3.0 Gbit/in² to 4 Gbit/in² in products and greater than 10 Gbit/in² in recording demonstrations. For the first half of this decade, areal density growth for magnetic recording products has increased by 60% each year. In order to sustain this growth rate into the next ten years, much emphasis has been placed on improving the recording system with higher output sensor designs, lower noise and higher coercivity media, and more robust head disc interfaces. However, little discussion exists on the impact the 60% growth rate in areal density has on the physical dimensions and critical features of the thin film magnetoresistive head structure. This review describes the basic magnetoresistive head structure, details the basic thin film process required to fabricate the head structure, identifies the critical device features of the head, and comments on the extendibility of these features by a comparison with semiconductor device processes and geometries