Polymeric Void Filling for High-Resolution HAMR Feature Formation
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Solution Overview
Problem
Existing photolithography methods are resolution-limited due to depth of focus limitations when forming features on sloped walls of deep voids, such as those found in heat-assisted magnetic recording (HAMR) heads, which require precise critical dimension lithography and are challenging due to topography on the void walls and bottom surfaces.
Innovation Solution
The method involves filling voids with a polymeric material, forming a photoresist layer, creating a gap in the photoresist, and etching the polymeric material to form features within the void, using techniques like spin coating, curing, and plasma etching, with optional hard mask layers to enhance etching capabilities and achieve high aspect ratio features.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If traditional photolithography methods are used to form features on sloped walls of deep voids, then the process is simpler, but the resolution is limited due to depth of focus limitations
Solution Approach 1:
The void is filled with a polymeric material before photolithography, creating a planar surface that eliminates topography issues. This preliminary filling action allows subsequent photolithography to achieve high resolution without the depth of focus limitations that would otherwise occur on sloped walls of deep voids
Solution Approach 2:
A polymeric filling material is introduced as an intermediary substance between the void structure and the photolithography process. This material acts as a mediator that provides a flat, planar surface for photoresist deposition, enabling precise feature formation without directly modifying the void geometry
2Manufacturing precision
If photolithography is performed directly on voids with topography, then the process steps are fewer, but the feature formation precision deteriorates due to sloped walls and surface irregularities
Solution Approach 1:
The void is pre-filled with polymeric material to create a planar surface before photolithography, eliminating the need to perform lithography directly on sloped walls. This preliminary action of filling transforms the problematic topographic surface into a flat substrate suitable for high-precision feature formation
Solution Approach 2:
The surface topology parameter is changed from sloped/irregular to planar by filling the void with polymeric material. This parameter change in surface flatness enables subsequent photolithography to achieve high precision feature formation that would be impossible on the original topographic surface
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 approach enables the formation of very small features within larger voids with topography, overcoming the limitations of traditional photolithography by allowing for precise feature creation in deep trenches with sloped walls and complex geometries, such as those needed for HAMR write poles.
Implementation Method 1
filling the void having at least one sloped wall with a polymeric material; forming a layer of photoresist over the polymeric material
Implementation Method 2
forming a gap in the layer of photoresist
Implementation Method 3
etching the polymeric material exposed by the gap in the layer of photoresist to form the at least one feature
Data Source
AI summary
A method of forming a feature in a void, the method including filling the void having at least one sloped wall with a polymeric material; forming a layer of photoresist over the polymeric material; forming a gap in the layer of photoresist; and etching the polymeric material exposed by the gap in the layer of photoresist to form a feature.