Read Sensor Electrical Isolation During Fabrication
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Solution Overview
Problem
As areal recording densities for storage discs increase, there is a need for technological advances in disc drives to electrically isolate read sensors during fabrication to prevent shorting and ensure accurate data storage operations.
Innovation Solution
A method involving the deposition of read sensor layers and an electrically conductive layer, followed by forming an isolation structure around the read sensors to break the electrical path between the sensors and ground, using techniques such as photolithography and ion milling to create a ring-shaped isolation structure that surrounds the read sensors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If read sensors are fabricated without electrical isolation structures, then fabrication process is simpler and faster, but electrical shorting occurs between sensors and ground causing unreliable operation
Solution Approach 1:
The patent applies preliminary action by forming the electrically conductive layer and isolation structures during the fabrication process before the read sensors are fully operational. Specifically, the conductive layer is deposited coplanar with the sensor layers, and isolation structures are formed by removing portions of this layer, preventing shorting before it can occur during subsequent fabrication steps or operation.
Solution Approach 2:
The patent applies the extraction principle by removing portions of the electrically conductive layer to create isolation structures. This selective removal extracts the conductive material from areas where it would create unwanted electrical paths, thereby isolating the read sensors electrically while maintaining the conductive layer in areas where electrical connection is desired.
2Reliability
If isolation structures are formed by removing electrically conductive layer, then electrical shorting is prevented, but additional fabrication steps are required
Solution Approach 1:
The patent merges the formation of the electrically conductive layer with the deposition of sensor layers by making them substantially coplanar. This combining of operations allows the conductive layer to serve dual purposes: providing electrical connection where needed and forming isolation structures where removed, thereby integrating isolation functionality into the existing fabrication flow without requiring completely separate process steps.
Data Source
AI summary
A method includes depositing a plurality of layers over a substrate. The layers include read sensor layers and an electrically conductive layer substantially coplanar with the read sensor layers and substantially surrounding the read sensor layers. The electrically conductive layer is in contact with at least one of the read sensor layers. The electrically conductive layer provides an electrical path between the at least one of the read sensor layers and ground. The method further includes forming an isolation structure around the read sensor layers by removing a portion of the electrically conductive layer substantially surrounding the read sensor layers. The isolation structure is substantially coplanar with the read sensor layers and substantially surrounds the read sensor layers. The isolation structure breaks the electrical path between the at least one of the read sensor layers and the ground.