Multichannel CPP Sensor Array Milling for Tape Head Modules

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Solution Overview

Problem

In magnetic storage systems, particularly tape drive systems, achieving high data density and minimizing tape head spacing poses challenges due to issues like gap erosion and sensor susceptibility to abrasion, which affects the performance and reliability of multichannel current perpendicular to plane head modules.

Innovation Solution

The implementation of a tape head module with an array of current perpendicular to plane sensors, where each sensor's resistance is within 10% of the median resistance value, and the use of an abrasion-resistant barrier layer to protect tunnel magnetoresistance sensors from scratches and shorts, along with specific milling angles to prevent smearing and enhance sensor yield.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If the spacing between the tape head and magnetic tape is minimized to increase data density, then the recording performance is improved, but the sensors become more susceptible to abrasion and gap erosion

Engineering Contradiction:

Improvespacing between head and tapeVSAvoidsensor susceptibility to abrasion

Core Design Contradiction:

Manufacturing precisionVSReliability

Solution Approach 1:

An abrasion-resistant barrier layer is introduced as an intermediary between the tunnel magnetoresistance sensors and the magnetic tape. This barrier layer protects the sensors from direct contact and abrasion while maintaining the minimized spacing configuration, allowing the system to achieve both high data density and sensor reliability.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The tape head module employs composite material structures, including the abrasion-resistant barrier layer combined with tunnel magnetoresistance sensors. This composite approach provides both the mechanical protection needed to withstand abrasion and the magnetic sensing capabilities required for high-density recording.

Inventive Principle:

Principle #40Composite materials

2Quantity of substance

If multichannel current perpendicular to plane head modules are used to increase data storage density, then the storage capacity is improved, but the consistency of sensor resistance becomes more difficult to maintain

Engineering Contradiction:

Improvedata storage densityVSAvoidsensor resistance consistency

Core Design Contradiction:

Quantity of substanceVSManufacturing precision

Solution Approach 1:

The invention employs parameter changes in the fabrication process, specifically controlling deposition conditions and annealing parameters to achieve consistent sensor resistance across multiple channels. By optimizing these process parameters, the system maintains resistance consistency while increasing the number of sensing channels for higher storage density.

Inventive Principle:

Principle #35Parameter changes

3Measurement precision

If tunnel magnetoresistance sensors are used to achieve high performance, then the sensing capability is improved, but the susceptibility to scratches and shorts increases

Engineering Contradiction:

Improvesensing capabilityVSAvoidsusceptibility to scratches and shorts

Core Design Contradiction:

Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The abrasion-resistant barrier layer serves as a protective intermediary between the fragile tunnel magnetoresistance sensors and the abrasive magnetic tape. This barrier allows the high-performance sensors to function without direct exposure to harmful abrasion, scratches, and potential shorts.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The barrier layer is applied beforehand to cushion and protect the tunnel magnetoresistance sensors from abrasive damage before the sensors are exposed to the magnetic tape during operation. This preventive protection maintains sensor integrity and reliability.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This configuration enhances data storage density, reduces wear and friction, and increases the reliability of multichannel tape recording heads by ensuring consistent sensor resistance and protecting against abrasive damage, leading to improved operational performance and reduced module failure rates.

Implementation Method 1

an array of at least eight current perpendicular to plane sensors

Methodology Applied

Scientific EffectMagnetoresistance: Magnetoresistance

Data Source

PatentUS10079034B2Mass production of multichannel current perpendicular to plane head modules via preferred milling

Publication Date: 2018.09.18 INTERNATIONAL BUSINESS MACHINE CORPORATION

AI summary

An apparatus according to one embodiment includes a tape head module having an array of at least eight current perpendicular to plane sensors. None of the sensors has a resistance more than about 10% away from the resistances of its nearest neighbors. An apparatus according to another embodiment includes a tape head module having an array of at least eight current perpendicular to plane sensors. The resistance of each sensor is within about 10% of the median resistance value of all sensors in the array.