Hard Mask Etch Selectivity for Sub-20 nm Imprint Lithography
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Solution Overview
Problem
Current nano-fabrication techniques, such as imprint lithography, face challenges in achieving high fidelity pattern transfer at sub-20 nm feature sizes due to limited etch selectivity and feature height, leading to unreliable pattern transfer and fidelity issues in semiconductor and hard disk drive industries.
Innovation Solution
The use of hard mask materials like Chromium (Cr), Silicon (Si), Al2O3, and SiO2, deposited through techniques such as gap-fill CVD or atomic layer deposition, increases etch selectivity and preserves pattern feature height during the etch process, allowing for high fidelity sub-20 nm pattern transfer by providing a significant etch process window.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional imprint lithography is used for sub-20 nm features, then pattern transfer can be achieved, but etch selectivity is limited and feature height is reduced leading to unreliable pattern transfer
Solution Approach 1:
The patent changes the material parameter of the mask layer from conventional photoresist to hard mask materials (Cr, Si, Al2O3, SiO2) which have fundamentally different etch selectivity properties. This material substitution enables etch selectivity of 50:1 or more, directly resolving the contradiction between pattern transfer fidelity and reliability by providing a mask layer that maintains its structural integrity and selective etching capability throughout the pattern transfer process.
Solution Approach 2:
The patent employs composite material structures combining the formable layer with overlying hard mask materials (Cr, Si, Al2O3, or SiO2). This composite approach integrates the patterning capability of the formable layer with the etch resistance of the hard mask materials, achieving both high pattern transfer fidelity and reliability simultaneously by leveraging the complementary properties of each material layer.
2Manufacturing precision
If etch process is performed to transfer pattern, then pattern is transferred into substrate, but feature height is lost and selectivity is insufficient
Solution Approach 1:
The patent fundamentally changes the etch process parameters by introducing hard mask materials with dramatically different etch selectivity (50:1 or more). This parameter change simplifies the etch process complexity because the high selectivity automatically provides a larger process window, reducing the need for complex process control and multiple etching steps while maintaining high pattern transfer accuracy.
3Ease of manufacture
If conventional materials are used for mask layer, then process is simple, but etch selectivity is limited and pattern fidelity deteriorates
Solution Approach 1:
The patent changes the material composition parameters of the mask layer from conventional photoresist to hard mask materials (Cr, Si, Al2O3, SiO2). While this requires additional deposition steps, the materials can be deposited using standard semiconductor fabrication techniques, maintaining ease of manufacture. The critical improvement is in pattern feature fidelity, which is enhanced by the superior etch selectivity and structural stability of these hard mask materials during the pattern transfer process.
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 achieves etch selectivity of 50:1 or more, ensuring reliable and uniform pattern transfer into the substrate, overcoming the limitations of existing methods and enabling high-density storage and semiconductor applications.
Implementation Method 1
deposited through techniques such as gap-fill CVD or atomic layer deposition
Implementation Method 2
deposited through techniques such as gap-fill CVD or atomic layer deposition
Implementation Method 3
increases etch selectivity and preserves pattern feature height during the etch process
Data Source
AI summary
Methods of increasing etch selectivity in imprint lithography are described which employ material deposition techniques that impart a unique morphology to the multi-layer material stacks, thereby enhancing etch process window and improving etch selectivity. For example, etch selectivity of 50:1 or more between patterned resist layer and deposited metals, metalloids, or non-organic oxides can be achieved, which greatly preserves the pattern feature height prior to the etch process that transfers the pattern into the substrate, allowing for sub-20 nm pattern transfer at high fidelity.