Lithographic tools for producing patterned films composed of gas phase generated nanocrystals

Single sized PbS nanocrystals are selectively deposited from the gas phase onto photoresist patterned substrates at atmospheric pressure, forming patterned nanocrystal thin films. Selective deposition is obtained by means of electrostatic control of the charged nanocrystals in the gas phase. The nanocrystal deposition process is characterised by low cost and high parallelism. A lift off process is introduced which removes the photoresist without removing the nanocrystal film in the interested area. Thus, further processing can follow the nanocrystal film deposition. During the deposition of nanocrystals out of the gas phase a preferred deposition into resist openings, i.e. onto the substrate surface is observed. An electrostatic model is developed to explain this focusing effect yielding smaller line width compared with the resist pattern.