P2. Negative pattern transfer with wet and dry etching.
     First step will be connected with thin film metal evaporation by PVD technique, which can be used afterwards as an etching mask during pattern transfer.
     Second step of the work will be done with negative tone resist characterization as electron sensitive material and as a mask material during pattern transfer. Another resist properties characterization will be focused on thin film thickness as a function of its viscosity, spinning angular velocity and its roughness changes after each processing step. Students will be asked to characterize negative e-beam resist by its sensitivity, contrast, process window and its spin curves.
     Third step will be the e-beam lithography method. This will involve full turn with data preparation from 2D layout coding down to internal JEOL format conversion and job control files creation. Some aspects of the e-beam method in terms of e-beam writing conditions and system calibration will be discussed. An e-beam exposure will follow.

     Fourth step will be the resist development with addressing some aspects of post exposure baking, especially for the case when CAR ( chemically amplified resists ) are used. Process window definition will be introduced and discussed with factors influencing its shape. Optical microscopy


inspection will be done with discussion of how polarized light method can be used for better feature size evaluation.
    Fifth step will be based on wet etching of the thin metal film resulting from previous step, which will be used as negative etching mask. Several aspects of the wet etching chemistry and its selectivity will be addressed. Final inspection with optical microscopy and SEM topographical measurements will conclude the experimental part of the project.
    Bonus assignment ( for ambitious students ) will be based on plasma etching of the substrate with the thin metal film resulting from last step as positive etching mask. Several aspects of the dry etching chemistry and its selectivity will be addressed. Final inspection with optical microscopy and SEM topographical measurements will conclude the experimental part of the project.


Piotr Jedrasik