US Patent 7274998 - Near-field photolithography using nano-LEDs

http://www.freepatentsonline.com/7274998.html

This patent from Intel presents a very interesting alternative to conventional optical lithography that employs a nanowire crossbar arrays of intersecting p-doped and n-doped nanowires. The intersections of the nanowires form light emitting diodes which may be used to pattern a resist of a substrate at nanoscale dimensions. The device acts as a sort of programmable mask which may save a great amount of cost in high resolution semiconductor manufacture. Interestingly this device uses a nanowire crossbar as a major component for implementation which is similar to the nanoscale crossbar used by HP in constructing high density memory and logic devices. Claim 1 reads:

1. An apparatus comprising: an array of nanowires placed at a distance to a resist layer, the array forming a plurality of light emitting diodes (LEDs), the distance corresponding to a near field region of light emitted by the LEDs with respect to the resist layer; and a control circuit coupled to the array to control the LEDs to emit the light to pattern a feature in the resist layer.

US Patent 7232771 - Flexible electrostatic nanoimprint stamp

http://www.freepatentsonline.com/7232771.html

This patent is directed to a new type of nanoimprint lithography employing electrostatic charging to transfer nanoparticle patterns onto a substrate. Although it is not the first patent to use electrostatic transfer in an imprint lithography system (see US Patent 7223444) it adds the feature of a flexible substrate as the stamp structure. Claim 1 reads:

1. A method of depositing nanoparticles on a substrate, comprising: obtaining a flexible stamp having a pattern formed thereon, the flexible stamp including a flexible overlayer of semiconductor material forming the pattern; applying the flexible stamp to the substrate to form a charge pattern on the substrate; and depositing nanoparticles on the charged pattern on the substrate.

US Patent 7223444 - Electrostatic nanoimprint stamp

http://www.freepatentsonline.com/7223444.html

Nanoimprint lithography is another nanolithography process which is being promoted by a variety of companies such as Hewlett-Packard and which has some promise of parallel processing capabilities which will be necessary for mass production. This patent from a company called QuNanoAB proposes an interesting variant on nanoimprinting which uses a nanoimprint mold to create an electrostatic latent image (as in photocopying) on a substrate. The electrostatic pattern then attracts molecules or nanoparticles to the substrate. This method seems to have some advantages over other nanoimprint techniques since the nanoimprint stamp does not need to contact the material being patterned and thus may have a longer life expectancy since there is less potential for soiling or wear. Claim 1 reads:

1. A method comprising the steps of: forming one or more electrically-charged regions of predetermined shape on an insulating surface of a solid first material by contacting portions of said surface corresponding to said one or more regions with a solid material of a tool so as to transfer electric charge from said tool to said surface; and permitting particles of a second material to flow in a vicinity of said one or more electrically-charged regions, to interact with said one or more electrically-charged regions.

US Patent 7166786 - Nanoimprint Lithography Doping

http://www.freepatentsonline.com/7166786.pdf

Semiconductor fabrication used in making integrated circuits usually requires a step of adding a dopant material to silicon via diffusion or ion implantation which can be costly. Imprint lithography is an alternative maskless lithography technique being explored which basically uses a stamping method to directly transfer a pattern to a target substrate. This patent from Borealis Technical Ltd. has priority going back to 1998 and presents a fairly broad claim to using this technique for semiconductor doping. Claim 1 reads:

1. A method for the induction of a band gap in a substance, comprising the steps of: (a) mounting a material on a substrate, (b) forming at least one nanostructure in said material by pressing a nanostructured mold into said material, said nanostructure having a relief causing de Broglie interference of elementary particles.