Thin-Film Magnetic Head Seed Layer Extraction for Shielding
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Solution Overview
Problem
Conventional thin-film magnetic heads with multiple shield layers suffer from adjacent track erasure (ATE) and wide area track erasure (WATE) due to differences in magnetic flux direction between shield layers, leading to data errors and erasure issues.
Innovation Solution
A manufacturing method for thin-film magnetic heads where a partial seed layer arrangement structure is used to prevent the seed layer from appearing on the medium-opposing surface, ensuring that the magnetic flux is properly absorbed by the shield layers, and the shield layers are laminated on a substrate with a main magnetic pole layer and thin-film coil.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a multiple shield layer structure is used to prevent magnetic flux leakage, then recording reliability is improved, but adjacent track erasure and wide area track erasure occur due to seed layer differences
Solution Approach 1:
The invention extracts and removes the seed layer from the medium-opposing surface by forming it only in recesses. This eliminates the harmful magnetic flux interaction caused by seed layers on the surface while preserving the shield layer structure's ability to prevent magnetic flux leakage.
Solution Approach 2:
The seed layer is formed with local quality differences - present in recess areas but absent on the medium-opposing surface. This localized formation allows the seed layer to serve its electrical grounding function while avoiding the harmful magnetic flux interactions that cause adjacent track erasure.
2Reliability
If seed layer is formed on the medium-opposing surface, then electrical grounding is improved, but magnetic flux direction differences cause data errors
Solution Approach 1:
The invention extracts the seed layer from the medium-opposing surface while maintaining its electrical grounding function through recess-based formation. This separation eliminates the magnetic flux direction conflicts that cause data errors while preserving the grounding capability.
Solution Approach 2:
The recess structure acts as an intermediary that allows the seed layer to exist without directly contacting the medium-opposing surface. This intermediate geometry enables electrical grounding while preventing harmful magnetic flux interactions with the recording medium.
3Ease of manufacture
If conventional plating method is used to form shield layers, then manufacturing simplicity is maintained, but magnetic flux absorption is insufficient due to crystal direction differences
Solution Approach 1:
The invention changes the geometric parameters of the seed layer formation - from full surface coverage to restricted recess areas. This parameter change improves magnetic flux absorption by eliminating the harmful crystal direction differences at the medium-opposing surface while maintaining manufacturing simplicity through a modified plating process.
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 method improves ATE and WATE by ensuring that the magnetic flux is effectively absorbed, reducing data errors and enhancing recording accuracy, and also reduces the magnetic path length, improving flux rise time and signal transition characteristics.
Implementation Method 1
a first shield part is formed by plating method, and then a second shield part is formed by plating method to overlie the first shield part
Implementation Method 2
a thin-film coil which generates a magnetic field passes through the inside of the main magnetic pole layer
Implementation Method 3
electric current is passed through the plating solution to cause a plating film made of a magnetic material to grow on the substrate
Data Source
AI summary
A thin-film magnetic head is constructed such that a main magnetic pole layer, a lower shield layer, an upper shield layer and a thin-film coil are laminated on a substrate. A method of manufacturing the thin-film magnetic head has a lower shield layer forming step. This step comprises a step of forming a first lower shield part in a lower shield planned area, including a planned line along the medium-opposing surface, a step of forming a partial lower seed layer having a partial arrangement structure in which the partial lower seed layer is arranged on a lower formation zone except a lower exception zone including the planned line, a step of forming a second lower shield part on the partial lower seed layer.