Thin Film Magnetic Head Concave Interlayer Surface

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Solution Overview

Problem

The existing manufacturing methods for thin film magnetic heads result in irregularly reflected light during photolithography, leading to deviations in frame dimensions and increased electric resistance due to convex interlayer connection surfaces, which can cause short circuits and inefficiencies in coil layer formation.

Innovation Solution

A thin film magnetic head with a metal lamination part featuring a concave interlayer connection surface, formed by machining or CMP using acidic slurry, to ensure accurate frame formation and reduced electric resistance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a convex interlayer connection surface is formed by plating, then the contact part can be formed to connect lower and upper coil layers, but light is irregularly reflected during photolithography causing frame dimension deviations and potential short circuits

Engineering Contradiction:

Improveconnection reliabilityVSAvoidframe dimension precision

Core Design Contradiction:

ReliabilityVSManufacturing precision

Solution Approach 1:

The patent inverts the conventional convex interlayer connection surface into a concave shape. This inversion prevents irregular light reflection during photolithography that causes frame dimension deviations, while still maintaining electrical connection between coil layers. The concave surface allows light to be reflected toward the inside (between frames) rather than outward, eliminating the manufacturing precision problems associated with convex surfaces.

Inventive Principle:

Principle #13The other way round (Inversion)

Solution Approach 2:

The patent changes the geometric parameter of the interlayer connection surface from convex to concave. This parameter change fundamentally alters the light reflection behavior during photolithography, preventing frame width expansion and dimension deviation while maintaining the electrical connection function between lower and upper coil layers.

Inventive Principle:

Principle #35Parameter changes

2Loss of energy

If contact parts are formed adjacent to each other to reduce wiring line length, then electric resistance is reduced, but the convex surface causes light reflection issues that may lead to short circuits

Engineering Contradiction:

Improveelectric resistanceVSAvoidshort circuit prevention

Core Design Contradiction:

Loss of energyVSReliability

Solution Approach 1:

By inverting the surface geometry from convex to concave, the patent eliminates the harmful outward light reflection that causes frame dimension deviation and potential short circuits. This allows contact parts to be positioned adjacent to each other for minimal wiring length and reduced electric resistance without compromising reliability through short circuits.

Inventive Principle:

Principle #13The other way round (Inversion)

3Volume of moving object

If frames are made thinner to reduce upper coil layer contact area, then space is optimized, but convex surface light reflection causes frame cutting and dimension deviation

Engineering Contradiction:

Improvecoil layer spaceVSAvoidframe dimension accuracy

Core Design Contradiction:

Volume of moving objectVSManufacturing precision

Solution Approach 1:

The concave surface inversion prevents light from being reflected outward during photolithography, eliminating the frame cutting and dimension deviation problems that occur with convex surfaces. This enables frames to be made thinner for optimized space utilization without sacrificing manufacturing precision.

Inventive Principle:

Principle #13The other way round (Inversion)

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

The concave interlayer connection surface allows for precise frame formation and reduced electric resistance, preventing short circuits and enhancing the accuracy and efficiency of coil layer formation in thin film magnetic heads.

Implementation Method 1

when the frames are formed in a S photolithography process, light is incident on the convex surface of each contact part and then irregularly reflected from the convex surface during the exposure

Methodology Applied

Scientific EffectLight reflection: Reflection

Implementation Method 2

CMP using acidic slurry, to ensure accurate frame formation and reduced electric resistance

Methodology Applied

Scientific EffectChemical etching: Oxidation

Data Source

PatentUS7760466B2Thin film magnetic head with a metal lamination part having concave connection surface

Publication Date: 2010.07.20 TDK CORP

AI summary

A thin film magnetic head with a metal lamination part and method of manufacturing the same are provided. The thin film magnetic head including a metal lamination part in which an upper metal layer is laminated on a lower metal layer. The metal lamination part is formed in the laminated structure. An interlayer connection surface between the lower metal layer and the upper metal layer of the metal lamination part is formed in a concave shape that is curved toward the lower metal layer.