Low cross talk interconnect for magnetic recording head

Read sensor in a magnetic recording head is susceptible to EOS from the cross talk induced by the write current transition. A significant component comes from the electrical interconnect between the head and the pre-amplifier. The magnitude increases as the transition time shortens, the line length increases and the read/write line separation decreases. As the read sensor dimension shrinks and becomes more delicate for higher recording density, such as TMR, it is more susceptible to the cross talk. The interconnect typically consists of two pairs of lines; one for write and one for read. For read sensor, it is the differential mode cross talk which is critical. It is well known that wire twisting can significantly reduce cross talk. However, with the planar microstrip line structure of interconnect commonly used today, it is difficult to cross the traces. Recently, progress was made that vias between trace and the stainless ground plane can be created. As a result, trace-pair twisting can be achieved with an innovative structure, where one trace is terminated at a via which connects to a short segment of isolated stainless steel to cross over the other trace then reconnects to the remaining trace segment through a second via. The objective of this study is to verify the concept and demonstrate the significance of this effect. It also provides insight to understand some of the characteristics of cross talk in an interconnect for magnetic recording head.