Interference Lithography Technology for exposing periodic submicron patterns seamlessly, using the contrast generatede by light interference
Our interference lithography system
Our technologies for Interference Lithography
Coherent optical system
Interference of two coherent lights on overlaid area produces a periodic pattern.
The periodic photo intensity is exposed to the photo resist. Fabricated pattern period is affected by the crossing beam angle, and fine patterns can be produced on the same order as the wavelength. Our laser interference lithography can create high visibility interference fringe by accurate wavefront.
High presicion mechanics
Our high precision work stage realizes fine interference lithography.
The right figure shows result of stage followability evaluation for step movement command. Actual position accurately matches the command position.
Scanning overlapped phase interference lithography
Scanning overlapped phase interference lithography method is a new technology. As the first step, a spot fringe pattern generated by two-beam interference is scanned direction along the grid on the wafer. As the second step, the spot is moved just the integer multiple length of its fringe period, then the spot is exposed again over the 1st fringe pattern. The reason moving amount of spot pattern must be the integer multiple length is to match fringe phases between 1st and 2nd scan perfectly to obtain high contrast exposure.
Features of interference lithography technology
Slant patterning
Slanted structure can be created by tilting the optical system.
Free and stable system allow to perfom a variety of evaluation.
Dots array patterning
Dot patterns can also be created by precisely performing two exposures with roated angle of the wafer.
we can made square or hexagonal array array by changing the rotation angle of the wafer.
Sub-micrometer patterning
UV laser and stable system can fabricate sub-micrometer pitch patterning.
The SEM image shows 180nm pitch of patterning by interference lithography. It is able to support period up to 150nm.
Seamless patterning
Scanning overlapped phase interference lithography realizes a seamless pattern without stitching caused by Step & Repeat exposure on an entire 8-inch substrate.
Patterning on curved surface
In terms of the depth of focus(DOF), patterning is possible on the order of mm. It enables to process that exceeds the restrictions of flatness and flatness.
