Method and system for providing a read sensor in a magnetic recording transducer using focused ion beam scan polishing

A method for fabricating a read sensor on a substrate for a read transducer, the read transducer having a field region and a device region in which the read sensor resides, the method comprising:

• depositing a read sensor stack including a plurality of layers on the substrate;
• depositing a hard mask layer on the read sensor stack, the hard mask layer having a plurality of hard mask layer thicknesses;
• performing a hard mask focused ion beam scan (FIBS) polishing on the hard mask layer such that a greater amount of hard mask layer is removed for a greater hard mask layer thickness of the plurality of hard mask layer thickness;
• providing a photoresist mask having a photoresist mask pattern on the hard mask layer;
• and
• transferring the photoresist mask pattern to the hard mask layer, forming a hard mask having a pattern, the pattern covering a first portion of the read sensor stack corresponding to the read sensor, covering a second portion of the read sensor stack distal from the read sensor, and exposing a third portion of the read sensor stack between the first portion and the second portion of the read sensor stack;
• defining the read sensor in a track width direction from the read sensor stack, the defining the read sensor including substantially removing the third portion of the read sensor stack, the read sensor having an inboard junction angle and an outboard junction angle;
• performing a critical junction (CJ) FIBS polishing of the transducer, the step of performing the CJ FIBS polishing including
• measuring the inboard junction angle and the outboard junction angle;
• and
• scanning across the substrate while ion polishing such that the ion polishing removes a greater amount of read sensor for a smaller of the inboard junction angle and the outboard junction angle;
• depositing an insulting layer on the read sensor;
• depositing a hard bias structure after the step of depositing the insulating layer the hard bias structure including a magnetic layer and a capping layer;
• planarizing the transducer;
• removing a remaining portion of the hard mask, a top surface of the read sensor being exposed, a remaining portion of the hard bias structure having a notch corresponding to the read sensor therein, the notch having a notch height;
• performing a notch FIBS polishing of the hard bias structure after the step of removing the remaining portion of the mask, the polishing FIBS polishing removing a portion of the hard bias structure to reduce the height of the notch, the step of performing the notch FIBS polishing further including
• measuring at least a plurality of notch heights across the substrate;
• scanning across the substrate while ion polishing such that a greater amount of the hard bias structure is removed for the greater notch height of the plurality of notch heights;
• providing a stripe height mask covering a fourth portion of the read sensor and a portion of the hard bias structure in a stripe height direction;
• defining a stripe height of the read sensor;
• performing a TMR FIBS polishing of the field region of the transducer, the TMR FIBS polishing removing a remaining portion of the read sensor stack in the field region;
• providing an insulating layer for electrically insulating the read transducer, the insulating layer having a plurality of insulating layer thicknesses;
• performing a refill FIBS polishing of the insulating layer, the refill FIBS polishing removing a portion of the insulating layer based on the plurality of insulating layer thicknesses;
• depositing a capping layer;
• removing the stripe height mask;
• and
• performing an additional planarization.

A method for fabricating a read sensor on a substrate for a read transducer, the read transducer having a field region and a device region in which the read sensor resides, the method comprising:

• depositing a read sensor stack including a plurality of layers on the substrate;
• providing a stripe height mask covering a first portion of the read sensor stack in a stripe height direction;
• defining a stripe height of the read sensor from the read sensor stack;
• performing a tunneling magnetoresistance (TMR) focused ion beam scan (FIBS) polishing of the field region of the transducer, the TMR FIBS polishing removing a remaining portion of the read sensor stack in the field region;
• providing an insulating layer that electrically insulates the read transducer;
• removing the stripe height mask;
• performing a planarization;
• providing a mask on the on the read sensor stack, the mask having a pattern, the pattern covering a second portion of the read sensor stack corresponding to the read sensor, covering a third portion of the read sensor stack distal from the read sensor, and exposing a fourth portion of the read sensor stack between the second portion and the third portion of the read sensor stack;
• defining the read sensor from the read sensor stack in a track width direction, the defining the read sensor including substantially removing the fourth portion of the read sensor stack, the read sensor having an inboard junction angle and an outboard junction angle for the read sensor track width;
• performing a critical junction (CJ) FIBS polishing of the transducer, the CJ FIBS polishing removing a portion of the read sensor based on the inboard junction angle and the outboard junction angle;
• depositing a hard bias structure;
• planarizing the transducer;
• removing a remaining portion of the mask.