Focused ion beam/lift-out transmission electron microscopy cross sections of block copolymer films ordered on silicon substrates

Thin poly(styrene₂₁₀-b-2-vinylpyridine₂₀₀) and poly(2-vinylpyridine₉₄-b-styrene₇₆₀-b-2-vinylpyridine₉₄) films spun cast on silicon and annealed at 180°C for 3 days were directly cross sectioned in less than 1 h using the focused ion beam (FIB) lift-out technique. We show that with the FIB procedure, it is possible to produce cross sections that reveal structure near the silicon interface and hence the surface induced phase transitions could be examined and compared quantitatively with theoretical models. Atomic force microscopy, dynamic secondary ion mass spectrometry, and transmission electron microscopy were used to characterize the films. (C) 2000 Elsevier Science Ltd.