Reader designs of shield to shield spacing improvement

A read head including a magnetoresistive (MR) sensor with a top spin valve configuration, comprising:

• (a) a bottom shield having a top surface;
• (b) a first stack of layers including a seed layer contacting the bottom shield top surface, and a free layer (FL), non-magnetic spacer, and first pinned layer (PL1) in a seed layer/FL/non-magnetic spacer/PL1 configuration, the first stack has a first set of two sidewalls extending a first height from an air bearing surface (ABS), a track width in a cross-track direction, and a back side at the first height distance;
• (c) a second stack of layers including a second pinned layer (PL2), coupling layer, reference layer (RL), and first capping layer that are sequentially formed on a top surface of the PL1 layer, the second stack has a first width in a cross-track direction, a second set of two sidewalls that extend a second height greater than the first height from the ABS, and a back side connecting the second set of two sidewalls;
• and
• (d) a third stack of layers comprising an antiferromagnetic (AFM) layer that pins a magnetization direction in the PL2 layer, the third stack has a front side that is recessed at least a first height distance from the ABS and that faces the first stack back side, and the third stack has a back side formed along a vertical plane in a down-track direction where the vertical plane includes the second stack back side.

A read head including a magnetoresistive (MR) sensor, comprising:

• (a) a bottom shield with a center section having a top surface, and two side sections formed on opposite sides of the bottom shield center section at an air bearing surface (ABS) and separated by a first width, the two side sections have a top surface formed a first distance in a down-track direction below the bottom shield center section top surface;
• (b) a first stack of layers including a first seed layer contacting the top surface of each bottom shield side section, a middle antiferromagnetic (AFM) layer, and an upper first pinned layer (PL1), the first stack forms a continuous stripe around two sidewalls and back side of an overlying third stack and is comprised of two side portions that connect to a back portion, each side portion has a second width in a cross-track direction, an outer sidewall that connects to a first stack back side at a first height from the ABS, and and an inner sidewall that connects to a front side of the back portion at a second height from the ABS;
• (c) a second stack of layers including a second pinned layer (PL2) that contacts a PL1 layer top surface, a coupling layer, and reference layer (RL), the second stack has two sidewalls that each share a vertical plane with a first stack outer sidewall and extend a first height from the ABS;
• and
• (d) the overlying third stack of layers aligned above the bottom shield center section and comprising a non-magnetic spacer contacting a top surface of the reference layer, a middle free layer, and an upper capping layer, the third stack has a track width less than the first width, and the two sidewalls that extend to a back side thereof formed a third height from the ABS.

A method of fabricating a magnetoresistive (MR) sensor wherein an antiferromagnetic (AFM) layer is recessed a certain distance from an air bearing surface (ABS) in order to reduce reader shield spacing, comprising:

• (a) providing a bottom shield and sequentially forming a seed layer, reference layer, coupling layer, pinned layer (PL2), non-magnetic spacer, free layer, and a first capping layer on a top surface of the bottom shield;
• (b) etching through portions of the first capping layer, free layer, and non-magnetic spacer to form a first stack that extends a first height from the ABS;
• (c) depositing a first isolation layer along a back side of the first stack, the first isolation layer covers a top surface of the PL2 layer that is greater than a first height distance from the ABS;
• (d) etching through the first isolation layer except a portion that is within a gap distance of the first stack back side, the etching continues through a back portion of the PL2 layer and stops a first distance below a top surface of a front portion of the PL2 layer to form an opening;
• and
• (e) filling the opening with a second stack of layers including a lower pinned layer (PL1), an AFM layer, a second capping layer, and a second isolation layer such that a top surface of the second isolation layer is substantially coplanar with a top surface of the first capping layer.

A method of fabricating a MR sensor wherein an antiferromagnetic (AFM) layer is embedded in a bottom shield in order to reduce reader shield spacing, comprising:

• (a) providing a first bottom shield layer and sequentially forming a first seed layer, AFM layer, first pinned layer (PL1), and a first capping layer on a top surface of the first bottom shield layer;
• (b) etching through portions of the first seed layer, AFM layer, PL1 layer, and first capping layer to form a first stack with two side sections each having an inner sidewall that extends to a front side of a back section at a first height from an air bearing surface (ABS), and an outer sidewall that extends to a back side of the back section at a second height from the ABS, the two side sections are separated by an opening having a first width in a cross-track direction and each has side section has a second width in a cross-track direction;
• (c) depositing a second bottom shield layer that is a bottom shield center section and an overlying second seed layer to fill the opening, and performing a planarization process so that the second seed layer top surface is essentially coplanar with a top surface of the PL1 layer;
• (d) sequentially forming a second pinned layer (PL2), coupling layer, reference layer, non-magnetic spacer, free layer, and second capping layer on the top surface of the second seed layer and PL1 layer;
• (e) etching through portions of the non-magnetic spacer, free layer, and second capping layer to form a second stack of layers having a non-magnetic spacer/free layer/second capping layer configuration with a track width between two sidewalls that extend a third height from the ABS to a back side thereof;
• the track width is less than the first width, the second stack is aligned above the bottom shield center section;
• and
• (f) forming sidewalls and a back side on the reference layer, coupling layer, and PL2 layer to form a third stack with a reference layer/coupling layer/PL2 layer configuration.