Maro Publications

Nanoimprinting

Notes

*12/3/2012

Maro Encyclopedia

Comments

Patents with Abstracts

Decorating

Microimprinting

Nanotechnology

Imprint Lithography

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Notes

3. “An exemplary nano-fabrication technique is commonly referred to as imprint lithography. Exemplary imprint lithography processes are described in detail in numerous publications, such as U.S. patent application publication 2004/0065976 filed as U.S. patent application Ser. No. 10/264,960, entitled, "Method and a Mold to Arrange Features on a Substrate to Replicate Features having Minimal Dimensional Variability"; U.S. patent application publication 2004/0065252 filed as U.S. patent application Ser. No. 10/264,926, entitled "Method of Forming a Layer on a Substrate to Facilitate Fabrication of Metrology Standards"; and U.S. Pat. No. 6,936,194, entitled "Functional Patterning Material for Imprint Lithography Processes," all of which are assigned to the assignee of the present invention and incorporated herein by reference.

The fundamental imprint lithography technique disclosed in each of the aforementioned U.S. patent application publications and U.S. patent includes formation of a relief pattern in a polymerizable layer and transferring a pattern corresponding to the relief pattern into an underlying substrate. The substrate may be positioned upon a motion stage to obtain a desired position to facilitate patterning thereof. To that end, a template is employed spaced-apart from the substrate with a formable liquid present between the template and the substrate. The liquid is solidified to form a solidified layer that has a pattern recorded therein that is conforming to a shape of the surface of the template in contact with the liquid. The template is then separated from the solidified layer such that the template and the substrate are spaced-apart. The substrate and the solidified layer are then subjected to processes to transfer, into the substrate, a relief image that corresponds to the pattern in the solidified layer.”

[Choi et al, US Patent 8,282,383 (10/9/2012)]

2. “In fabricating semiconductor integrated electrical circuits, integrated optical, magnetic, mechanical circuits, micro devices, and the like, lithography is one of the key processing methods. Lithography creates a pattern in a thin film located on a substrate, so that, in subsequent process steps, the pattern will be replicated in the substrate or in another material located on the substrate.

Nanoimprint lithography (NIL) is a simple nanolithography process with low cost, high throughput and high resolution. It creates patterns by mechanical deformation of imprint resist and subsequent processes. The imprint resist is typically a monomer or polymer formulation that is cured by heat or UV light during the imprinting. Adhesion between the resist and the template is controlled to allow proper release. There are many different types of nanoimprint lithography, including thermoplastic nanoimprint lithography and photo nanoimprint lithography.

Thermoplastic nanoimprint lithography (T-NIL) is the earliest nanoimprint lithography developed by Prof. Stephen Chou's group. In a standard T-NIL process, a thin layer of imprint resist (thermoplastic polymer) is spin coated onto the sample substrate. Then the mold, which has predefined topological patterns, and the sample are pressed together under a certain pressure. When heated up above the glass transition temperature of the polymer, the pattern on the mold is pressed into the softened polymer film. After being cooled down, the mold is separated from the sample and the pattern resist is left on the substrate. A pattern transfer process (e.g. reactive ion etching) can be used to transfer the pattern in the resist to the underneath substrate.

In photo nanoimprint lithography (P-NIL), a photo (UV) curable liquid resist is applied to the sample substrate and the mold is normally made of transparent material (e.g. fused silica). After the mold and the substrate are pressed together, the resist is cured in UV light and becomes solid. After mold separation, a similar pattern transfer process can be used to transfer the pattern in resist onto the underneath material.

However, the central goal in today's nanoimprint lithography is to make NIL appropriate to mass-productions for improving NIL performance and yield. Modification of row materials referred to as mold material and resist. As far as the resist, lithography generally employed it as mask of different processes, because of it properties of thermal plastic, UV curing and easy removal such as polymethyl methacrylate (PMMA), PS, and HSQ and so on. Otherwise, due to the resist's low modulus, poor solvent resistance, high thermal expansion coefficient, and uneasily patterned, these disadvantages lead to distortions and deformations of the resident imprinting nanostructures. The materials for mold, quartz and Si or SiO2 wafer were usually applied, while this kind of mold generally fabricated by electronic beam lithography (EBL), it is easily crushed under high pressure.”

[Zhu et al, US Patent 8,282,381 (10/9/2012)]

1. “Nanoimprint lithography is a method of fabricating nanometer scale patterns. It is a simple nanolithography process with low cost, high throughput and high resolution. It creates patterns by mechanical deformation of imprint resist and subsequent processes. The imprint resist is typically a monomer or polymer formulation that is cured by heat or UV light during the imprinting. Adhesion between the resist and the template is controlled to allow proper release.”

(Wikipedia, Nanoimprint Lithography, 6/18/2012)

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2. “In a nano-imprint method that presses a mold having a micro pattern formed by electron beam exposure to a substrate, such as a wafer, having a resin material (resist) applied thereto to transfer the pattern to the resist, a circular or disk-shaped mold is generally used with respect to a circular or disk-shaped substrate, such as optical recording media or magnetic recording media (for example, see Patent Document 1).

In such a transfer method, a substrate having a transfer layer is held by a first holding unit, a mold is held by a second holding unit with a suction force, reference positions of the mold and the substrate are aligned with each other with a certain distance, and pressure is applied between the mold and the substrate so that the mold is pressed to the substrate, thereby transferring an uneven pattern of the mold to the surface of the substrate. Patent document 1: Japanese Patent Application Publication No. 2006-040321.”

[Hashimoto et al, US Patent 8,192,194 (6/5/2012)]

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Interested!!
Bookmark this page to follow future developments!.
(RDC 6/5/2012)

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Roger D. Corneliussen
Editor
www.maropolymeronline.com

Maro Polymer Links
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Copyright 2012 by Roger D. Corneliussen.
No part of this transmission is to be duplicated in any manner or forwarded by electronic mail without the express written permission of Roger D. Corneliussen
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* Date of latest addition; date of first entry is 6/18/2012.