The controlled generation of nanopatterns on functional substrates is an essential process step in nanotechnology. Serial methods such as electron beam lithography yield precisely positioned structures a few tens of nanometers in size with low throughput. Conventional optical lithography allows generating feature sizes in the 100-nm range on a large scale. Their downscaling to the 50-nm range is associated with a large increase in technical complexity and costs. Block copolymer (BC) lithography has emerged as an inexpensive highthroughput alternative for creating patterns with periods in the sub-50-nm range. 1-8 To this end, thin BC films 1,9,10are coated onto the substrates to be patterned. The BC templates thus obtained contain hexagonal arrays of either spheres or cylinders oriented normal to the film plane, which consist of the minor component. This pattern can be transferred into the underlying substrate by reactive ion etching (RIE). 1-4,11 The etch contrast between the blocks of BCs is usually too low for efficient pattern transfer. To overcome this problem, the stability of the resist domains under RIE conditions can be improved by staining them with heavy elements. 1 BC templates with sufficient etch contrast may also be prepared from BCs containing blocks of organometallic polymers, taking advantage of the higher stability of the organometallic domains with respect to organic domains. 2