Samenvatting

Within the semiconductor industry the demand for ever decreasing chip and resistor sizes has forced the use of extreme ultraviolet (EUV) waves in lithography machines. The older generation lithography machines used lenses to focus the waves. These lenses aren't transparent for EUV waves with a wavelength of 13.5 nm. Instead of lenses mirrors are used to focus the waves. Extensive research has been performed on the multilayer mirrors used in the upcoming lithography machines. The total reflection of these mirrors have almost reached the theoretical limit.
The demand for smaller computer chips and more energy efficient chips is driving the industry to the next step in EUV lithography. The next industry standard for EUV lithography machines is already set. The next generation machines will be using waves with a wavelength twice as small (6.7 nm). The wavelength reduction will not only cause the multilayer thickness to reduce, but will also require a different set of materials. The new multilayer mirrors will consist of boron and lanthanum layers. The thickness of these layers will be of the same scale as imperfections within the interfaces between these two layers. The use of new materials will result in all sorts of technical difficulties. For instants, previous experiments have shown that the multilayers aren't stable under thermal load. The changes that occur during the exposure to EUV radiation will result in a compaction or an expansion of the multilayer period. Changes in the multilayer period will result in a loss of reflectivity. Structural analysis is performed in order to understand the effects that are causing the period changes. The analysis uses hard x-rays to determine the structure of different samples. These samples were all annealed at different temperatures.