Selectable Trapezoidal Read Sensors for Data Storage Precision
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Solution Overview
Problem
As areal recording densities increase in data storage devices, there is a need for technological advances in disc drives to address the variability in electrical reader width of trapezoidal read sensors, which affects their performance due to lithographical and lapping errors, leading to higher MT10 sigma values.
Innovation Solution
The formation of multiple trapezoidal read sensors with selection of the sensor having the most suitable electrical reader width, closest to a target value, to reduce MT10 sigma and improve bit error rate and stability, by forming and testing trapezoidal read sensors from triangular structures with varying tip positions and intentional shifts during fabrication.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If trapezoidal read sensors are fabricated using conventional lithography and lapping processes, then manufacturing is simpler and faster, but electrical reader width varies significantly leading to higher MT10 sigma values
Solution Approach 1:
The patent divides the read sensor fabrication into multiple segments by creating several read sensors with different tip positions within the same slider. This segmentation allows statistical selection of the sensor with the closest electrical reader width to the target value, thereby improving manufacturing precision while managing complexity through modular testing and selection
Solution Approach 2:
The patent changes the tip position parameter of the read sensors during fabrication to create intentional shifts in electrical reader width. By fabricating sensors with varying tip positions (e.g., different distances from the trailing edge of the slider), the process creates diversity in electrical reader width values, enabling selection of the optimal sensor that closest matches the target specification
2Reliability
If multiple read sensors are formed and tested per slider, then the best sensor can be selected to reduce MT10 sigma, but manufacturing time and cost increase
Solution Approach 1:
The patent applies preliminary action by forming multiple read sensors with different tip positions during the initial fabrication process, before final assembly and testing. This allows the selection of the optimal sensor to be made early in the manufacturing process, improving reliability while minimizing the impact on productivity by avoiding rework or additional complex testing steps later
Solution Approach 2:
The patent creates multiple copies of read sensors within the same slider, each with slightly different tip positions. By fabricating these duplicate sensors with intentional parameter variations, the system enables statistical selection of the best performing sensor, thereby improving bit error rate stability while maintaining manufacturing efficiency through parallel fabrication
3Quantity of substance
If trapezoidal read sensors are used to increase areal recording density, then storage capacity improves, but variability in electrical reader width degrades performance
Solution Approach 1:
The patent changes the tip position parameter during fabrication to create intentional shifts in electrical reader width. This parameter change allows the system to compensate for lithographical and lapping errors that occur during trapezoidal sensor formation, thereby maintaining manufacturing precision while preserving the high areal recording density enabled by the trapezoidal geometry
Solution Approach 2:
The patent implements feedback by measuring the electrical reader width of each fabricated read sensor and comparing it to the target value. This measurement feedback enables the selection of the sensor with the closest match to the desired specification, thereby correcting for manufacturing variations and maintaining precise electrical reader width control despite the challenges of trapezoidal fabrication
Data Source
AI summary
A method of forming a read head. The method includes forming first and second read sensors that are substantially trapezoidal in shape. A first read measurement is performed on a storage medium using the first read sensor. A second read measurement is performed on the storage medium using the second read sensor. Based on a comparison of the first and second read measurements to a predetermined quantity, either the first read sensor or the second read sensor is selected to be operational in a data storage device.