Flexible Template Imprint Lithography for Substrate Undulation Control
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Solution Overview
Problem
In nano-scale fabrication using imprint lithography, controlling the thickness of features formed on a substrate is challenging due to undulations on the substrate surface, leading to variations in feature dimensions and distortions during etching processes.
Innovation Solution
A flexible template made from fused silica is used to conform to the substrate surface, allowing for uniform thickness control through capillary action and fluid pressure application, ensuring consistent feature formation and minimizing distortions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a rigid template is used in imprint lithography, then the structural stability of the template is maintained, but the ability to conform to substrate surface undulations is lost, causing variations in feature thickness
Solution Approach 1:
The patent employs a flexible template made from fused silica that can deform to conform to the substrate surface. This flexible template allows the imprinting material to achieve uniform thickness distribution despite substrate undulations, directly resolving the contradiction between maintaining structural stability and achieving conformal contact.
Solution Approach 2:
The patent changes the physical state of the template from rigid to flexible, allowing it to adapt its shape according to the substrate surface profile. This parameter change enables the template to maintain contact with varying surface heights while preserving feature thickness uniformity during the imprinting process.
2Ease of manufacture
If capillary action is used to fill the volume with conformable material, then the material distributes itself according to surface topology, but complete filling of recesses requires additional fluid pressure application
Solution Approach 1:
The patent incorporates a fluid dispense system that applies controlled fluid pressure to the conformable material. This hydraulic approach complements capillary action by providing the additional pressure needed to force material into recesses and ensure complete volume filling, while maintaining ease of manufacture through automated control.
3Manufacturing precision
If the template is made flexible to conform to substrate undulations, then feature thickness uniformity is improved, but the force required to separate the template from solidified material increases
Solution Approach 1:
The patent divides the template into multiple segments or zones that can independently deform and separate from the solidified material. This segmentation allows different portions of the template to be separated at different rates and forces, reducing the peak separation force required while maintaining the flexibility needed for conformal contact.
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 solution achieves uniform thickness control of features within specified tolerances, enabling complete patterning of the substrate without unpatterned regions, thereby overcoming the challenges of substrate undulations and ensuring accurate feature replication.
Implementation Method 1
A first sub-portion of the volume is charged with the conformable material through capillary action between the conformable material and one of the mold and the substrate
Data Source
AI summary
A method for spreading a conformable material between a substrate and a template having a mold. The method comprises positioning the mold to be in superimposition with the substrate defining a volume therebetween. A first sub-portion of the volume is charged with the conformable material through capillary action between the conformable material and one of the mold and the substrate. A second sub-portion of the volume is filled with the conformable material by creating a deformation in the mold.