Soft imprinting

Registration Using the Lock-and-key Mechanism in Soft Imprinting... 

Soft imprinting using flexible stamp has ample potential to be applied for reel-to-reel process [54, 55]. To achieve fast process in reel-to-reel device fabrication, passive alignment process between flexible stamp and substrate is needed rather than active optical alignment procedure. As a passive alignment process, lock and key mechanism was studied between flexible stamp and substrate in soft imprinting. 

G. D. Hawker, C. J., Highly Versatile and Robust Materials for Soft Imprint Lithography Based on Thiolene Click Chemistry. Adv. Mater. 2008,20,3728-3733. 

Choi, W.M. and Park, 0.0. (2005) A soft-imprint technique for submicron structure fttbrication via in situ polymerization. Nanotechnology. 15, 135-138. 

A common example utilizing the same concept is a woman s pointed high heel shoes. She can leave imprint marks on a vinyl tile floor from impression of her shoe heel points. Another example would be the Eskimo, who can walk on soft snow without sinking by varying the area of contact of his footprint with broad snowshoes. 

Hiratani, H., et al. 2005. Ocular release of timolol from molecularly imprinted soft contact lenses. Biomaterials 26 1293. 

Tamper-proof seals are added to discourage unauthorized or undetected field adjustments. Once testing is complete, a metal identification tag (of soft lead, which is easy to imprint, yet impervious to corrosion) is attached to the SRV. The tag records the location number, set pressure, and test date. 

Nanoscale assembly Self-assembling micellar structures [113,114] Bio-self-assembly and aggregation [115,116] Nanomanipulation [117,118] Soft lithography [119,120] Molecular imprinting [121,122] Layer-by-layer electrostatic deposition [123,124] Chemical vapor deposition [125]... 

Fig. 6.4. Etching a fluidic channel pattern into a silicon or glass wafer, (a) The channel is created in the substrate, (b) The negative of the channel is created in silicon and used subsequently as mold for imprinting of soft lithography.

But this is usually not the case. The reason is that in imprint lithography, mold durability is maintained by choosing the proper polymer resist layer thickness such that the mold protrusion will not contact the hard substrate directly. In other words, a thin viscous polymer fluid exists between the mold protrusions and the substrate surface and acts as a soft cushion, which effectively protects the nanofeatures on the mold. The trade-off of this is the existence of a residual resist layer that is present in the recessed regions, which has to be removed by a separate plasma etching step before pattern definition can be completed. 

Figure 28 A schematic representation of so-called nanostructuiing by way of a soft-lifliography process. (A) Filling of depressions in the polymer plate (B) imprinting on a solid surface (see text) Source-. Courtesy of Nature.

These results on physisorption-induced work function changes on metals are also interesting with regard to the common assumption on metal/molecule hetero-interfaces, namely that metals are the hard and molecules are the soft component. The theoretical results clearly demonstrate that with respect to the charge density the metal acts as soft and the molecule as the hard partner, since the - essentially undisturbed - organic molecule imprints its shape in the charge distribution on the metal surface. 

While imprint lithography does not involve the use of an elastomeric stamp and hence is not a soft lithography technique, it is a next-generation patterning technique that has gained tremendous attention for generating nanoscale features, which is... 

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