Near-field light generating element tip geometry for heat-assisted magnetic recording
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Solution Overview
Problem
The challenge in heat-assisted magnetic recording is to create a near-field light generating element with a sharply pointed top end to achieve a smaller spot diameter for increased recording density, while existing methods like etching with a photoresist mask often result in a rounded tip, making it difficult to form a sharply pointed near-field light generating element.
Innovation Solution
The near-field light generating element is designed with a triangular-prism-shaped structure, featuring inclined surfaces and a sharply pointed tip, achieved through a method involving multiple etching steps and the use of a polishing stopper layer and non-metallic inorganic coating layers to prevent rounding, allowing for precise formation of a small spot diameter and sufficient intensity near-field light.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a photoresist mask is used to etch the near-field light generating element, then the manufacturing process is simple, but the top end becomes rounded and cannot achieve a sharply pointed shape
Solution Approach 1:
A sharply pointed protrusion is formed on the photoresist mask before etching begins. This pre-formed pointed structure serves as a template that transfers the sharp geometry to the near-field light generating element during the etching process, preventing the rounding that would normally occur with standard photoresist masks.
Solution Approach 2:
The photoresist mask acts as an intermediary carrier that holds the sharply pointed protrusion. This intermediary structure enables the transfer of sharp geometry to the metal layer without requiring direct manipulation of the final element shape, solving the contradiction between manufacturing simplicity and shape precision.
2Area of moving object
If the top end of the near-field light generating element is made sharply pointed, then the spot diameter decreases and recording density increases, but the manufacturing difficulty increases
Solution Approach 1:
The sharply pointed protrusion is prepared in advance on the photoresist mask, converting the difficult task of forming a sharp point during etching into a simpler process of transferring a pre-formed sharp geometry. This reduces manufacturing difficulty while achieving the small spot diameter needed for high recording density.
Solution Approach 2:
The problem of forming a sharp point in two dimensions is solved by adding a temporal dimension - preparing the pointed shape in advance on the mask before the etching process. This transforms a difficult in-process operation into a preliminary preparation step, reducing overall manufacturing complexity.
3Ease of manufacture
If the near-field light generating element has a rounded tip, then the manufacturing process is easier, but the near-field light intensity and concentration are insufficient
Solution Approach 1:
The sharp protrusion is formed on the photoresist mask before etching, ensuring that the near-field light generating element will have a sharply pointed tip after etching. This preliminary formation of the sharp geometry ensures sufficient near-field light intensity and concentration while maintaining manufacturing ease through the use of a modified but still simple photoresist mask approach.
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 configuration enables the generation of near-field light with a small spot diameter and sufficient intensity, effectively increasing recording density and preventing temperature rises in the near-field light generating element, while maintaining a precise shape to concentrate surface plasmons efficiently.
Implementation Method 1
A surface plasmon is excited based on the light propagated through the waveguide. The surface plasmon is propagated to the near-field light generating part. The near-field light generating part generates near-field light based on the surface plasmon.
Implementation Method 2
The near-field light generating part generates near-field light based on the surface plasmon. The front end face has a sharply pointed tip that forms the near-field light generating part.
Data Source
AI summary
A near-field light generating element has an outer surface. The outer surface includes a bottom surface, first and second inclined surfaces, an edge part that connects the first and second inclined surfaces to each other, and a front end face located in a medium facing surface. The front end face includes a first side that lies at an end of the first inclined surface, a second side that lies at an end of the second inclined surface, and a tip that is formed by contact of the first and second sides with each other and forms a near-field light generating part. Each of the first side and the second side has a lower part and an upper part that are continuous with each other. An angle formed between the upper part of the first side and the upper part of the second side is smaller than that formed between the lower part of the first side and the lower part of the second side.