Electrical Lapping Guide for Magnetic Recording Head Peg Length Control
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Solution Overview
Problem
Current lapping processes for manufacturing heat-assisted magnetic recording heads lack the necessary precision and control to achieve stringent tolerances required for the shape and dimensions of near field transducers, particularly in controlling the peg region length.
Innovation Solution
The use of electrical lapping guides (ELGs) with a conductive material and a lapping edge featuring an air-bearing plane axis perpendicular to the lapping axis, and a back edge with a plurality of notches, which are connected to electrical leads to monitor resistance and provide precise control over the lapping process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional lapping processes are used, then the manufacturing process is simple, but the manufacturing precision and control are insufficient to achieve stringent tolerances for peg region length
Solution Approach 1:
The patent implements real-time feedback by monitoring the electrical resistance of the ELG during the lapping process. As the peg region is lapped and its length changes, the resistance value changes accordingly. This resistance feedback is continuously measured and used to control the lapping process, enabling precise termination when the desired peg length is achieved, thus resolving the contradiction between precision and complexity.
Solution Approach 2:
The patent replaces traditional mechanical measurement and control methods with an electrical sensing system. Instead of using complex mechanical gauges or visual inspection to measure peg length, the system uses electrical resistance measurement of the ELG to infer peg length changes. This substitution of mechanical measurement with electrical sensing simplifies the control system while achieving higher precision.
2Measurement precision
If traditional measurement methods are used, then the device complexity is low, but the measurement precision is insufficient for controlling near field transducer dimensions
Solution Approach 1:
The patent substitutes mechanical measurement systems with an electrical resistance-based measurement system. The ELG's electrical resistance serves as a direct indicator of peg region length, eliminating the need for complex mechanical measurement apparatus. This electrical sensing approach provides high measurement precision while keeping the measurement system relatively simple.
Solution Approach 2:
The ELG acts as an intermediary element that translates mechanical changes (peg length variations) into electrical signals (resistance changes). This intermediary conversion allows for precise indirect measurement of peg length through electrical properties, achieving high measurement precision without direct mechanical contact or complex measurement equipment.
3Manufacturing precision
If lapping process is extended to achieve better precision, then the manufacturing precision improves, but the productivity decreases due to increased process time
Solution Approach 1:
The real-time resistance feedback system allows for precise control of the lapping process, enabling it to stop exactly when the desired precision is achieved rather than requiring extended over-lapping. This feedback-controlled termination optimizes the balance between precision and time, preventing unnecessary extended lapping that would reduce productivity.
Solution Approach 2:
The ELG provides self-service by automatically indicating through its resistance value when the peg length has reached the target specification. This self-indicating capability eliminates the need for continuous operator monitoring and manual measurement, allowing the process to achieve precision efficiently without extending processing time, thus maintaining productivity.
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 ELGs enhance the accuracy and control of the lapping process, allowing for precise measurement and adjustment of the peg region length of near field transducers, thereby improving the manufacturing of heat-assisted magnetic recording heads.
Implementation Method 1
The electrical lapping guide includes a body having a thickness along a wafer axis. The body has a first contact region and a second contact region having a minimal distance therebetween. The first contact region and the second contact region are configured to electrically connect the electrical lapping guide to electrical leads.
Implementation Method 2
a lapping edge comprising an air-bearing plane axis, the air-bearing plane axis being perpendicular to a lapping axis
Data Source
AI summary
An electrical lapping guide has a body with a thickness along a wafer axis, the body comprising a layer of conductive material having a resistivity. The conductive material layer comprises a first contact region and a second contact region, the first and second contact regions configured to electrically connect the electrical lapping guide to electrical leads. A lapping edge comprises an air-bearing plane axis perpendicular to a lapping axis, and a back edge opposite the lapping edge, the back edge comprising a plurality of notches.