As the evolution towards increasing integration densities continues in the integrated circuit manufacturing, new materials and thin film deposition methods will inevitably be needed. Atomic Layer Deposition (ALD) is one of the most promising film deposition techniques capable of meeting the strict requirements in future generation IC manufacturing. The self-limiting film growth mechanism of ALD ensures excellent conformality and uniformity over large areas, and atomic level composition and thickness control. In this paper, the present state of ALD of materials of an interest to microelectronics will be reviewed, including also the current understanding of the related chemistry, and challenges for the future research will be outlined. At present, there already exist many potential ALD processes for the following microelectronic materials: dielectrics (e.g. SrTiO@sub 3@, BaTiO@sub 3@, Ta@sub 2@O@sub 5@, Nb@sub 2@O@sub5@, ZrO@sub 2@, HfO@sub 2@ and Al@sub 2@O@sub 3@, and their multilayers and mixtures) for gate oxides and DRAM capacitors, and nitride (e.g. TiN, TaN, NbN, W@sub 2@N) diffusion barriers for metallizations. In addition, some metal (W, Ti, Ta, Cu) ALD processes have been reported as well. Further development of ALD will require increasing efforts in precursor chemistry supported by improved understanding of the growth mechanisms. For the latter, different approaches may be taken. Here a recently developed ALD-QMS-QCM setup enabling in situ characterization of ALD processes under the practically important flow type reactor conditions will be briefly introduced.