TDMR Read Transducer Shunt Design for EOS Protection
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Solution Overview
Problem
Two-dimensional magnetic recording (TDMR) transducers face misalignment issues due to skew angle and radius conditions, which can lead to Electrical Overstress (EOS) or Electrostatic Discharge (ESD) when using thin insulating films to reduce vertical separation between sensors, especially as more read sensors are added.
Innovation Solution
The implementation of a read transducer design with multiple read sensors separated by conductive magnetic middle shields and insulating layers, where the insulating layers have varying thicknesses and materials to reduce capacitive coupling and EOS/ESD risks, and the inclusion of shunt regions with electrical connections to manage electrical properties during manufacturing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If thin insulating films are used to separate adjacent readers' mid-shields, then vertical separation between sensors is reduced and skew angle misalignment is minimized, but the risk of Electrical Overstress (EOS) or Electrostatic Discharge (ESD) increases
Solution Approach 1:
The patent applies local quality by varying the thickness of insulating layers at different locations. Specifically, first insulating layers between adjacent read sensors have a first thickness, while second insulating layers have a second thickness different from the first. This localized variation allows optimization of electrical isolation at critical interfaces while maintaining adequate spacing elsewhere, thereby reducing EOS/ESD risk without compromising vertical separation precision.
Solution Approach 2:
The patent introduces mid-shields as intermediary structures between adjacent read sensors. These conductive magnetic mid-shields serve as electromagnetic shields that isolate adjacent sensors magnetically and electrically. By placing these intermediary shields between sensors, the design reduces capacitive coupling and provides additional protection against EOS and ESD while maintaining the benefits of reduced vertical separation.
2Adaptability or versatility
If more read sensors are added between the first outer shield and second outer shield, then TDMR functionality is enhanced, but the chance of EOS or ESD increases
Solution Approach 1:
The patent segments the space between outer shields by introducing multiple mid-shields that divide the region into separate zones. Each mid-shield creates an isolated electromagnetic environment for adjacent read sensors. This segmentation allows multiple sensors to coexist with reduced mutual interference and improved electrical isolation, enabling enhanced TDMR functionality while mitigating EOS/ESD risks through systematic compartmentalization.
Solution Approach 2:
The patent implements local quality through varied insulating layer thicknesses positioned strategically between different sensor pairs. By making insulating layers non-uniform—thicker in regions with higher electrical stress and thinner where spacing is critical—the design optimizes protection against EOS and ESD while accommodating a higher density of read sensors within the same structural envelope.
3Measurement precision
If vertical separation between sensors is reduced, then skew angle misalignment is reduced, but thin insulating films become vulnerable to EOS or ESD
Solution Approach 1:
The patent employs composite material structures combining conductive magnetic mid-shields with insulating layers of varying thicknesses. The mid-shields provide magnetic shielding and structural support, while the composite insulating layer configuration (with different thicknesses in different regions) provides tailored electrical isolation. This composite approach enables reduced vertical separation for better skew angle performance while the multi-layer composite structure resists EOS and ESD vulnerabilities.
Solution Approach 2:
The conductive magnetic mid-shields act as intermediary structures between adjacent read sensors. These mid-shields serve dual functions: they provide magnetic shielding to reduce cross-talk and they create physical separation zones that accommodate insulating layers. By introducing these intermediary elements, the design achieves reduced vertical separation for improved skew angle alignment while the intermediaries themselves protect against EOS and ESD through their shielding properties.
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 design improves the manufacturing of TDMR transducers by reducing skew effects, enhancing impedance and frequency performance, and mitigating cross-talk, while providing protection against EOS and ESD, thus improving the overall performance and reliability of the magnetic recording system.
Implementation Method 1
insulating layers have varying thicknesses and materials to reduce capacitive coupling
Implementation Method 2
read sensors separated by conductive magnetic middle shields and insulating layers
Data Source
AI summary
A method of making a magnetic head is provided. The method includes forming a first read sensor and a first electrical contact formed with a first shunt region. The method further includes forming a first mid-shield layer on the first read sensor, the first mid-shield layer being electrically connected to the first electrical contact. Additionally the method also includes forming a second mid-shield layer over the first mid-shield layer. Further, the method also includes forming a second read sensor over the second mid-shield layer, the second read sensor having a second electrical contact formed with a second shunt region electrically connected to the first shunt region.