You might consider using Dip Pen Nanolithography (DPN) to deposit resist or other material to form a grating pattern. The material you deposit could be the final grating structure or could be used as a resist to transfer the grating pattern to the underlying material. Roger Shile -----Original Message----- Dear All, Recently, I use AFM to fabricate micro-nano structure, along with other methods such as wet etching, sputter and photolithography. The first step is to fabricate nano-grating by AFM. I have used many photoresists such as SU-8 and AZ1800. I find that SU-8 is too sticky to form a groove. AZ1800 is better than SU-8, however, depth-to-width ratio is too small(1:10). The height of the groove is about 100nm, the groove bottom is about 300 nm, and the dap is nearly 750nm. Tip Radius (max.) is 20nm. What is the main reason that the dap comes to 750nm? I still can not find a suitable photoresist for AFM scratching. If you have advice, please tell me in details. Your help will be highly appreciated. Thank you!