Imprint Template Surface Energy Control for Gas Bubble Venting

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Solution Overview

Problem

Ultraviolet (UV) nano-imprint processes face issues with trapped gas bubbles in the resist, leading to void defects that interfere with pattern transfer and quality of master templates and stacks, due to uncontrolled liquid resist flow rates governed by surface tension differences between imprint templates and substrates.

Innovation Solution

Modifying the surface chemistry of imprint templates and substrates to control surface energy, either by increasing or decreasing surface tension, thereby altering interfacial flow rates to prevent gas trapping, using methods such as deposition of extremely hydrophobic materials or adhesion promoters to shift dominance in flow rates and ensure controlled wetting and filling of resist materials.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If the liquid resist flows rapidly to fill the imprint template voids by capillary action, then the filling speed is improved, but gas bubbles are trapped in the template voids creating void defects

Engineering Contradiction:

Improveliquid resist filling speedVSAvoidgas bubble trapping

Core Design Contradiction:

SpeedVSObject-affected harmful factors

Solution Approach 1:

The patent modifies surface energy parameters of the imprint template by depositing hydrophobic materials or adjusting surface chemistry. This changes the interfacial tension between the liquid resist and template surface, controlling the capillary action to allow gas bubbles to escape during the filling process while maintaining rapid filling speed.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent introduces an intermediary layer or surface treatment on the imprint template that mediates the interaction between the liquid resist and template. This intermediary surface property control allows the liquid resist to wet the template appropriately while providing a pathway for gas bubbles to escape, resolving the contradiction between fast filling and bubble-free imprinting.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Ease of operation

If the surface energy of the imprint template is increased to improve wetting, then the liquid resist spreads better, but gas bubbles are more likely to be trapped

Engineering Contradiction:

Improveliquid resist wettingVSAvoidgas bubble trapping

Core Design Contradiction:

Ease of operationVSObject-affected harmful factors

Solution Approach 1:

The patent optimizes the surface energy parameter of the imprint template to an intermediate value that balances wetting and gas release. By controlling surface energy within a specific range through material selection or surface treatment, the liquid resist achieves adequate wetting for complete void filling while maintaining sufficient gas permeability to prevent bubble trapping.

Inventive Principle:

Principle #35Parameter changes

3Productivity

If the capillary action is strengthened to accelerate resist filling, then the imprint process speed is improved, but gas bubbles are trapped due to rapid flow

Engineering Contradiction:

Improveimprint process speedVSAvoidvoid defect formation

Core Design Contradiction:

ProductivityVSManufacturing precision

Solution Approach 1:

The patent adjusts capillary pressure parameters by modifying template pore size, surface energy, and liquid resist surface tension to achieve optimal filling dynamics. The capillary action is tuned to provide sufficient driving force for rapid filling while maintaining flow conditions that allow gas bubbles to escape through the template rather than being trapped, thus improving productivity without sacrificing manufacturing precision.

Inventive Principle:

Principle #35Parameter changes

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 effectively reduces or eliminates trapped gas bubbles, enhancing the quality of UV imprint patterns and preventing void defects, thereby improving the fidelity of pattern transfer and the quality of fabricated stacks like bit-patterned media.

Implementation Method 1

The resist fluid fills the imprint template voids by capillary action

Methodology Applied

Scientific EffectCapillary action: Capillary Action

Implementation Method 2

The lower first surface energy in comparison to the second surface energy of the substrate avoids trapping gas in the resist by pushing gas toward the imprint template for venting

Methodology Applied

Scientific EffectSurface tension: Surface Tension

Data Source

PatentUS10828666B2Method of surface tension control to reduce trapped gas bubbles

Publication Date: 2020.11.10 SEAGATE TECH LLC

AI summary

A pattern imprint template incudes a patterned recesses and a layer formed over the patterned recesses. The pattern recesses form a pattern in a resist when brought in contact with a substrate with a resist thereon. The layer formed over the patterned recesses has a first surface energy. The first surface energy is lower in comparison to a second surface energy of the substrate with the resist thereon. The lower first surface energy in comparison to the second surface energy of the substrate avoids trapping gas in the resist by pushing gas toward the imprint template for venting through the patterned recesses.