Plasma characteristics and ion etching performance in hard disk drive slider fabrication processes

Abstract

A hard disk drive (HDD) is the permanent magnetic data storage and one of the most important components of computers, electronic devices and cloud data storage service facility. The data reading and writing are operated by the reader and writer parts of HDD head or slider. These reader and writer were made of multilayer thin ilms of different materials, forming a tunneling magnetoresistive (TMR) device. In HDD production, the ion beam etching (IBE) process was used in the preparation of surface patterns and cleaning in many fabrication steps. The Monte Carlo-based simulation package, SRIM was applied to calculate the etching yields and %energy loss of those materials in the TMR structure. The calculation showed that the etching yields of materials reach the maximum value, at an incident angle of 70° to the normal surface. The total etching yields of compounds were calculated from the etching yield of each element. The plasma characterization in an industrial-size IBE system has been performed to extract the plasma characteristic at different process conditions. The effects of process parameters in IBE system such as incident beam angle, ion beam current and gas flow in the system were analyzed. The floating potential of plasma in this IBE system with the electron compensation from a plasma bridge neutralizer (PBN) is 3 V, while the plasma potential is 2.5 V. The ion current densities in the actual system and the etching rate of different TMR materials were calculated.