Phase-Shift Lithography

Near-field phase shift lithography is a soft lithographic technique used to produce geometric shapes with size features at the nanoscale (approximately 40-80nm).This involves the production of a polymer mask containing the desired pattern to be... 

Phase shifting lithography Phase shift mask lithography Phase shift photolithography... 

Phase shift lithography is a lithographic technique to pattern sub-wavelength features by using a transparent phase shift mask and relies on the pi-optical phase-change of the exposure light field. 

Phase shift lithography, unlike the traditional photolithography that uses opaque masks to modulate the intensity of the light, produces patterns by exploiting the optical phase. Even though the mask features can be much larger than the... 

Phase-Shift Lithography, Fig. 1 Schematic illustration of the phase shift lithography. Both positive and negative photoresist can be used... 

In the case of phase shift lithography, mask pattern s height is predicted with the value of wavelength of used light, refractive index of... 

For attenuated phase shift lithography, light blocking materials, which have phase shifting characteristic, such as molybdenum silicide (MoSi), aluminum/aluminum nitride cermet, understoichiometric silicon nitride, tantalum silicon oxide composite, are used. All these materials record 4 15 % transmission at UV light... 

A typical fabrication process using the phase shift lithography is shown in Fig. 1 and Table 1. 

Imprint and Exposure Phase-Shift Lithography To solve the contact problem between phase shift mask and substrate, a new combination method is suggested. By using thermal imprint technique, photoresist can be patterned with specific geometry and it can be roUed as phase shift mask structure and photoresist layer at the same time. A photoresist has different refractive index from transparent elastomer or quartz, height of imprint mold needs to be calculated again with the equation above. Fabrication process flow is explained in Fig. 5. 

Phase-Shift Lithography, Fig. 4 SEM images of fabricated PR patterns by roll type phase shift lithography by rectangular phase mask (a), by circular phase mask (b),... 

Until now, fabrication of moth eye inspired nanostructures was quite costly and it was hard to make a large area sample, fri this point of view, phase shift lithography is a very promising method to fabricate it. The required pattern size is well matched with critical dimensicm of phase shift lithography and continuous fahricaticHi on... 

Phase-Shift Lithography, Fig. 6 (a) SEM image showing wellconnectedAl mesh pattern with 10pm period, (b) SEM image of 30 pm periodic A1 mesh pattern, (c)... 

Phase-Shift Lithography, Fig. 7 (a) Transmittance of various TME samples with three different thicknesses and two kinds of periods. Red line indicates the transmittance... 

Phase-Shift Lithography, Fig. 8 SEM images of moth eye (a) and moth eye inspired nanostructures (b). (a) from dartmouth college and (b) from Nanotechweb.org... 

Kwak MK, Ok JG, Lee JY, Guo U (2012) Continuous phase-shift lithography with a roll-type mask and application to transparent conductor fabrication. Nanotechnology 23 344008... 

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