Stress relaxation in Mo/Si multilayer structures

Abstract

The as-deposited stress in sputtered, 75-Å-period Mo/Si multilayers was measured to be approximately −350 MPa (compressive), and relaxed to approximately −150 MPa after thermal cycling to 200 °C. The multilayer period was found to decrease by 0.25 Å as a result of thermal cycling, with only a slight decrease in peak soft-x-ray reflectance. The stress-temperature behavior of individual Mo and Si films was also measured, and correlated with the multilayer behavior: stress relaxation in the multilayer is attributed to viscous flow associated with defect annihilation, occurring predominantly in the amorphous Si layers.

Pd/B_4C/Y multilayer coatings for extreme ultraviolet applications near 10 nm wavelength

“…However, we see a steady drop in compressive film stress as the sample is held at 100°C, and after cooling the stress has fallen to −407 MPa. This irreversible change in stress after thermal cycling to 100°C could be due to a number of causes relating to changes in the layer microstructure and interface properties of the film [20]. But in spite of this irreversible stress change, and regardless of its cause, the EUV data [ Fig.…”

<title>Fabrication of semitransparent multilayer polarizer and its application to soft x-ray ellipsometer</title>

“…However, the use of such a film for EUVL optics created new problems in that the intrinsic film stress caused deformation of the mirror substrate, which considerably degraded imaging performance. So, extensive investigations were carried out on the origin of that stress, and also on ways of controlling it, ranging from thermal treatment [17]and microstructural evolution [18] to background pressure [19]• The idea of directly controlling the film stress evolved out of developments in the fabrication of semitransparent multilayers. In addition, Kortright predicted that a transmissive multilayer filter could be used as a phase retarder [41•Positive control of the film stress and the new capabilities of transmissive multilayer films began a new age in the fabrication of semitransparent multilayer films.…”

Hydrogen-induced blistering of Mo/Si multilayers: Uptake and distribution

“…A similar enhancement is not evident at the outermost Si-on-Mo interface, although it may be masked by the high H-content in the "bulk" of the Mo layer. Macroscopically, the as-deposited Mo and Si layers in ML structures such as those currently under investigation are typically tensile and compressive, respectively [20,[39][40][41][42]54]. While the Si layers are amorphous, the Mo layers exhibit an amorphous-to-polycrystalline transition at a thickness of ~2 nm [43,45].…”