Western Digital Technologies, Inc.

Western Digital (fremont), Inc.

Chen-jung Chien

Ming Mao

Chih-Ching Hu

Daniele Mauri

Yung-Hung Wang

Yuankai Zheng

Ming Jiang

Guanxiong Li

Christian Kaiser

Zhitao Diao

Ronghui Zhou

Zhihong Zhang

Rongfu Xiao

Dujiang Wan

Anup Roy

Goncalo Marcos Baião De Albuquerque

Carlos Corona

Hongxue Liu

James Mac Freitag

Shaoping Li

Mahendra Pakala

Xiaoyong Liu

Gerardo Bertero

Qunwen Leng

Guanghong Luo

Yukimasa Okada

Shihai He

Matthew A Stevenson

Cheng-Han Yang

Rong Cao

Ann Lorraine Carvajal

Fang Chen

The present disclosure generally relates to a two-dimensional magnetic recording (TDMR) read head. The TDMR read head comprises a first sensor, a second sensor, and a middle shield (MS) disposed between the first and second sensors. The MS comprises a seed layer, an IrMn layer disposed on the seed layer, an insertion layer comprising Ru or CoFe disposed on the IrMn layer, a first NiFe layer having a pinned magnetization, and a cap layer disposed over the first NiFe layer. In one embodiment, the MS further comprises an Ru layer disposed on the first NiFe layer and a second NiFe layer disposed on the Ru layer, the second NiFe layer having a pinned magnetization in a direction antiparallel to the first NiFe layer. The insertion layer comprising Ru decreases an exchange energy of the MS. The insertion layer comprising CoFe increases an exchange energy of the MS.

Pinned shield with controllable exchange bias field

The present disclosure generally relates to a dual free layer two dimensional magnetic recording read head. The read head comprises a first lower shield, a first sensor disposed over the first lower shield, a first upper shield disposed over the first sensor, a read separation gap (RSG) disposed on the first upper shield, a second lower shield disposed over the RSG, a second sensor disposed over the second lower shield, and a second upper shield disposed over the second sensor. In some embodiments, the second lower shield comprises a CoFeHf layer. In another embodiment, the second lower shield is a synthetic antiferromagnetic multilayer comprising a first shield layer, a second shield layer, and a CoFe/Ru/CoFe anti-ferromagnetic coupling layer or a Ru layer disposed therebetween, the first and second shield layers comprising NiFe and CoFe. In yet another embodiment, the second lower shield comprises layers of Ru, IrMn, and NiFe.

Middle shields two-dimensional magnetic recording read heads

The present disclosure generally relates to a dual free layer two dimensional magnetic recording read head. The read head comprises a first lower shield, a first sensor disposed over the first lower shield, a first upper shield disposed over the first sensor, a read separation gap (RSG) disposed on the first upper shield, a second lower shield disposed on the RSG, a second sensor disposed over the second lower shield, and a second upper shield disposed over the second sensor. In one embodiment, the RSG comprises SiOand has a thickness of about 7 nm to about 14 nm. The SiOisolates the first sensor from the second sensor, and is a chemical mechanical processing (CMP) stop layer. In another embodiment, the RSG comprises a first sublayer comprising AlOx and a second sublayer comprising SiO. The thicknesses of the first and second sublayers are based on an adjustable capacitance.

Produce thinner DTS and adjustable capacitance for TDMR heads

The present disclosure generally relate to a read head and methods of forming thereof. Upon forming a dual free layer (DFL) sensor and a rear hard bias (RHB) structure on a seed layer, a photoresist is deposited on the DFL read head and the RHB structure. A refill layer is deposited on the photoresist and the seed layer adjacent to the DFL sensor and the RHB structure. Portions of the refill layer disposed on one or more sidewalls of the photoresist are removed, and a SiOx cap layer is deposited on the refill layer and on the one or more sidewalls. The photoresist is removed, and the SiOx cap layer and top surfaces of the DFL sensor and the RHB structure are planarized to form a substantially flat topography. The SiOx cap layer acts as a stop layer for the refill layer, and remains in the finished read head.

DFL read head with SiOx cap layer on AlOx refill layers

The present disclosure generally relates to a Wheatstone bridge array that has four resistors. Each resistor includes a plurality of TMR structures. Two resistors have identical TMR structures. The remaining two resistors also have identical TMR structures, though the TMR structures are different from the other two resistors. Additionally, the two resistors that have identical TMR structures have a different resistance area as compared to the remaining two resistors that have identical TMR structures. Therefore, the working bias field for the Wheatstone bridge array is non-zero.

Magnetic sensor array with different RA TMR film

The present disclosure generally relates to a read head assembly having a dual free layer (DFL) structure disposed between a first shield and a second shield at a media facing surface. The read head assembly further comprises a rear hard bias (RHB) structure disposed adjacent to the DFL structure recessed from the media facing surface, where an insulation layer separates the RHB structure from the DFL structure. The insulation layer is disposed perpendicularly between the first shield and the second shield. The DFL structure comprises a first free layer and a second free layer having equal stripe heights from the media facing surface to the insulation layer. The RHB structure comprises a seed layer, a bulk layer, and a capping layer. The capping layer and the insulation layer prevent the bulk layer from contacting the second shield.

Vertical junction to provide optimal transverse bias for dual free layer read heads

The present disclosure generally relates to read heads having dual free layer (DFL) sensors. The read head has a sensor disposed between two shields. The sensor is a DFL sensor and has a surface at the media facing surface (MFS). Recessed from the DFL sensor, and from the MFS, is a rear hard bias (RHB) structure. The RHB structure is disposed between the shields as well. In between the DFL sensor and the RHB structure is insulating material. The RHB is disposed on the insulating material. The RHB includes a RHB seed layer as well as a RHB bulk layer. The RHB bulk layer includes a first bulk layer and a second bulk layer, the first bulk layer having a different density relative to the second bulk layer.

Method to enhance magnetic strength and robustness of rear hard bias for dual free layer read

The present disclosure generally relates to a dual free layer (DFL) two dimensional magnetic recording (TDMR) read head. The read head comprises a first sensor, a first rear hard bias (RHB) structure disposed adjacent to the first sensor, an upper shield disposed over the first sensor and first RHB structure, a lower shield disposed over the upper shield, a second sensor disposed over the lower shield, and a second RHB structure disposed adjacent to the second sensor. A first surface of the first sensor is substantially flush or aligned with a first surface of the first RHB structure. A first surface of the second sensor is substantially flush or aligned with a first surface of the second RHB structure. The upper shield extends linearly from a media facing surface into the read head. The first lower shield is over-milled a greater amount of time than the second lower shield.

Planar design for sensors in a dual free layer read head

The present disclosure generally relates to a Wheatstone bridge array that has four resistors. Each resistor includes a plurality of TMR films. Each resistor has identical TMR films. The TMR films of two resistors have reference layers that have an antiparallel magnetic orientation relative to the TMR films of the other two resistors. To ensure the antiparallel magnetic orientation, the TMR films are all formed simultaneously and annealed in a magnetic field simultaneously. Thereafter, the TMR films of two resistors are annealed a second time in a magnetic field while the TMR films of the other two resistors are not annealed a second time.

Magnetic sensor array with single TMR film plus laser annealing and characterization

A tunneling magnetoresistance (TMR) sensor device is disclosed that includes four or more TMR resistors. The TMR sensor device comprises a first TMR resistor comprising a first TMR film, a second TMR resistor comprising a second TMR film different than the first TMR film, a third TMR resistor comprising the second TMR film, and a fourth TMR resistor comprising the first TMR film. The first, second, third, and fourth TMR resistors are disposed in the same plane. The first TMR film comprises a synthetic anti-ferromagnetic pinned layer having a magnetization direction of the reference layer orthogonal to a free layer. The second TMR film comprises a double synthetic anti-ferromagnetic pinned layer having a magnetization direction of the reference layer orthogonal to the magnetization of a free layer, but opposite to the magnetization direction of the reference layer of the first TMR film.

Magnetic sensor with dual TMR films and the method of making the same

The present disclosure generally relates to a Wheatstone bridge array comprising TMR sensors and a method of fabrication thereof. In the Wheatstone bridge array, there are four distinct TMR sensors. The TMR sensors are all fabricated simultaneously to create four identical TMR sensors that have synthetic antiferromagnetic free layers as the top layer. The synthetic antiferromagnetic free layers comprise a first magnetic layer, a spacer layer, and a second magnetic layer. After forming the four identical TMR sensors, the spacer layer and the second magnetic layer are removed from two TMR sensors. Following the removal of the spacer layer and the second magnetic layer, a new magnetic layer is formed on the now exposed first magnetic layer such that the new magnetic layer has substantially the same thickness as the spacer layer and second magnetic layer combined.

Magnetic sensor array with one TMR stack having two free layers

The present disclosure generally related to a two dimensional magnetic recording (TDMR) read head having a magnetic tunnel junction (MTJ). Both the upper reader and the lower reader have a dual free layer (DFL) MTJ structure between two shields. A synthetic antiferromagnetic (SAF) soft bias structure bounds the MTJ, and a rear hard bias (RHB) structure is disposed behind the MTJ. The DFL MTJ decreases the distance between the upper and lower reader and hence, improves the area density capacity (ADC). Additionally, the SAF soft bias structures and the rear head bias structure cause the dual free layer MTJ to have a scissor state magnetic moment at the media facing surface (MFS).

Two-dimensional magnetic recording reader with dual free layer magnetic tunnel junction

A tunneling magnetoresistance (TMR) sensor device is disclosed that includes one or more TMR sensors. The TMR sensor device comprises a first resistor comprising a first TMR film, a second resistor comprising a second TMR film different than the first TMR film, a third resistor comprising the second TMR film, and a fourth resistor comprising the first TMR film. The first TMR film comprises a reference layer having a first magnetization direction anti-parallel to a second magnetization direction of a pinned layer. The second TMR film comprises a reference layer having a first magnetization direction parallel to a second magnetization direction of a first pinned layer, and a second pinned layer having a third magnetization direction anti-parallel to the first magnetization direction of the reference layer and the second magnetization direction of the first pinned layer.

Magnetic sensor array with dual TMR film

A Wheatstone bridge array comprising a tunneling magnetoresistive (TMR) sensor and a method for manufacturing is disclosed. The bottom lead for the TMR sensor has a very small surface roughness due to not only chemical mechanical planarization (CMP) but also due to forming the bottom lead from multiple layers. The multiple layers include at least a bottom first metal layer and a top second metal layer disposed on the first metal layer. The second metal layer generally has a lower surface roughness than the first metal layer. Additionally, the second metal layer has a slower polishing rate. Therefore, not only does the second metal layer reduce the surface roughness simply be being present, but the slower polishing rate enables the top second metal film to be polished to a very fine surface roughness of less than or equal to &#x2dc;2 Angstroms.

Bottom leads chemical mechanical planarization for TMR magnetic sensors

The present disclosure generally relates to a Wheatstone bridge that includes a plurality of resistors comprising dual free layer (DFL) TMR structures. The DFL TMR structures include one or more hard bias structures on the side of DLF. Additionally, one or more soft bias structures may also be present on a side of the DFL. Two resistors will have identical hard bias material while two other resistors will have hard bias material that is identical to each other, yet different when compared to the first two resistors. The hard bias materials will provide opposite magnetizations that will provide opposite bias fields that result in two different magnetoresistance responses for the DFL TMR.

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Mountain View, CA, United States of America

Chen-jung Chien