Characterization of High Resolution Resists and Metal Shims by Scanning Probe Microscopy

Abstract

Technologies such as compact disc (CD) manufacturing, hologram embossing, and security printingrely on the reproduction of micro-patterns generated on surfaces by optical or electron-beam lithographicwriting onto electron-beam or photoresists. The periodicity of such patterns varies from sub-micron to severalmicrons, with depths up to 0.5 μm. The scanning probe microscope (SPM) is becoming a routine tool foranalysis of these micro-patterns, to check on depths and lateral dimensions of features. Direct scanning ofresist-covered plates is now possible, without damage, using resonant low-contact force SPM with etched siliconcantilevers. Metal shims produced from the master resist plates can also be scanned and checked for defectsprior to production of embossed foils. The present article discusses examples of the use of a Digital Instruments3100 microscope in analysis of production electron-beam lithography plates with a 0.5 μm resist thickness. Wealso examine features of nickel replicas (father and mother shims) produced by electroforming from theoriginal plate. With SPM measurements of the development profile of a particular plate, corrections can bemade to exposures and development times during production to correct errors. An example is given of sucha feedback process.