Latent image measurements in electron beam exposed polymethylmethacrylate

Undeveloped and unbaked paterns or latent images (LI) in polymethylmethacrylate (PMMA) have been observed and measured using different measurement techniques. Results from two common-path baseband optical techniques have been compared with the results of profiling LI using an atomic force probe. These results indicate that 5 Å detection limits in optical path length measurements are easily achievable at near video rates using simple optical systems.