In near-field photolithography, the size of the holes used to produce near-field light is critical. Moreover, the distance that near-field light reaches is in the order of tens of nanometers, which means that the mask perforated with the pattern to be transferred must be in very close contact with the photoresist layer. It was for this purpose that Canon has developed a photomask that uses thin-film base material. This kind of mask manufacturing technology is one of the big hurdles facing the development of next-generation lithography device.

The nature and performance of the photoresist that is exposed to near-field light is also important. The resist needs to serve not only as a medium to transfer the mask pattern to the surface of the substrate, but also as a mask layer itself in the later etching process that leaves the pattern on the substrate. Canon utilizes a bilayer photoresist to address these stringent demands.

As shown in the illustration, the photoresist consists of a lower and upper layer laid down in turn on the substrate. The upper later is exposed to the near-field light, transferring the pattern of the photomask, but it is the under layer that performs the role of the mask protecting the substrate in the etching process. This employment of a two-layer photoresist enables the creation of deeper grooves in the substrate.

However, no matter how good the photomask and photoresist are, the alignment will fail as a lithography device if the device performs poorly in such basic functions as positioning of the substrate and so forth. Ensuring a high degree of overall device precision is the third hurdle that needs to be overcome. Ironically it is in this "non-nanosize" area that the most serious hurdles remain in all existing areas of nanotechnology. Canon is tackling such problems through applying the state-of-the-art lithography device technology that it has developed to date.