Device and method for lithography

Abstract

Apparatus and method for transferring a pattern from a template (10) having a structured surface to a substrate (12) carrying a surface layer of a radiation polymerisable fluid (14). The apparatus comprises a first main part (101) and a second main part (102) having opposing surfaces (104;105), means for adjusting a spacing (115) between said main parts, support means (106) for supporting said template and substrate in mutual parallel engagement in said spacing with said structured surface facing said surface layer, a radiation source (110) devised to emit radiation into said spacing. A cavity (115) has a first wall comprising a flexible membrane (113) devised to engage said template or substrate, and means (114;116) are provided for applying an adjustable overpressure to a medium present in said cavity, whereby an even distribution of force is obtained over the whole of the contact surface between the substrate and the template. The apparatus further includes a heater device having a surface facing said spacing, for heating either fluid layer (14).

Description

FIELD OF THE INVENTION [0001] The invention relates to a device in connection with the lithography of structures on a micro or nanometre scale. In particular, the invention relates to imprint lithography on substrates or objects. BACKGROUND [0002] The trend in microelectronics, as well as in micromechanics, is towards ever smaller dimensions. Some of the most interesting techniques for fabrication of micro and submicro structures include different types of lithography. [0003] Photolithography typically involves the steps of coating a substrate with a photoresist material to form a resist layer on a surface of the substrate. The resist layer is then exposed to radiation at selective portions, preferably by using a mask. Subsequent developing steps remove portions of the resist, thereby forming a pattern in the resist corresponding to the mask. The removal of resist portions exposes the substrate surface, which may be processed by e.g. etching, doping, or metallisation. For fine scale...

AI Technical Summary

Benefits of technology

[0007] Accordingly, an object of the present invention is to provide methods and means for improving fabrication of structures comprising three-dimensional features on a micro or nanometre scale. In particular, it is an object to provide improved methods and means for transferring a pattern of such structures to substrates having widths of more than one inch, and even for 8 inch diameters, 12 inch diameters, and larger. An aspect of this object is to provide an apparatus and an associated process which is more cost effective and more versatile.

[0008] According to a first aspect, this object is fulfilled by an apparatus for transferring a pattern from a template having a structured surface to a substrate carrying a surface layer of a radiation polymerisable fluid, said apparatus comprising a first main part and a second main part having opposing surfaces, means for adjusting a spacing between said main parts, support means for supporting said template and substrate in mutual parallel engagement in said spacing with said structured surface facing said surface layer, a radiation source devised to emit radiation into said spacing, a cavity having a first wall comprising a flexible membrane devised to engage said template or substrate, means for applying an adjustable overpressure to a medium present in said cavity, and a heater device having a surface facing said spacing. Due to the flexible membrane, an absolutely even distribution of force is obtained over the whole of the contact surface between the substrate and the template, whereby patterning of large area substrates in a single imprint step is made possible.

Problems solved by technology

For fine scale replication, photolithography is limited by diffraction, which is dependent on the wavelength of the radiation used.

The larger the area to be imprinted, the larger the actual expansion and contraction, which can make the imprint process more difficult for larger surface areas.

Such a system is, however, not capable of handling large area substrate surfaces in a single imprint step.

This technique is therefore very time-consuming, and less than optimum for large scale production.

Furthermore, besides problems of repeated alignment errors, and high accuracy demands on the translation stage, this technique suffers from the drawback that continuous structures which are larger than said template size cannot be produced.

All in all, this means the productions costs may be too high to make this technique interesting for large scale production of fine structure devices.

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