Photolithography has been an important patterning technique in past decades. The technique could utilize the high energy beam scanning, which are efficient to fabricate structures under nanometer scale without using expensive mask.  

However, the patterning efficiency under the scale from nanometers to micrometers are extremely low. And it has restricted to its widely application. 

To solve the contradiction of super resolution and efficiency in photolithography, Prof. ZHENG Meiling’s team from the Technical Institute of Physics and Chemistry (TIPC) of the Chinese Academy and Sciences (CAS) and Prof. DUAN Xuanming’s team from Jinan University have proposed a far-field maskless optical projective nanolithography (MLOP-NL) strategy.  

This work is published in Nano Letters. The new protocol has enabled the cross-scale patterning with precise configuration could beyond the diffraction limit and achieve high efficiency.  

In this study, scientists firstly solved the problem on the improvement of resolution beyond micrometer. The resolution can be improved through the optical nonlinearity, the chemical nonlinearity of nonchemical amplified (non-CA) resist, and the millions times repeating irradiation of femtosecond pulse. A minimum feature size of 32 nm, λ/12 super resolution breaking the optical diffraction limit, has been achieved in MLOP-NL process by a single exposure.  

With the help of MLOP-NL strategy, it is flexible to achieve arbitrary cross-scale structures via simply changing the data of desired configuration. Furthermore, patch production could be performed by only repeating the process. Consequently, MLOP-NL technique provides a powerful tool allowing for achieving cross-scale patterns with both large-scale and precise configuration architectural feature. 

The work is highly possible to open up a new avenue for the high efficient lot manufacturing with the further development of higher frequency laser and rapid responsive stage industry. It will also show potentials to researchers working in diverse fields of nanoscience and nanotechnology, including nanodevices, nanostructures, and nanolithography. 

This work is supported by the National Key R&D Program, and the Natural Science Foundation of China.