Process for Preparing Molybdenum-Silicon Alloy Targets

With the development of emerging fields such as big data, artificial intelligence, and 5G communication, the critical dimensions of integrated circuits are constantly shrinking. As a high-precision tool used for pattern transfer in the lithography process, the quality of photomasks directly determines the final performance of circuits. Molybdenum silicide alloys with high silicon content have become key materials for the light-absorbing film layer in advanced photomasks due to their excellent properties such as optical tunability, ease of etching, chemical resistance, and radiation resistance. The quality of the film is highly dependent on the magnetron sputtering target material, and the development of high-uniformity and high-density molybdenum silicide alloy targets is of crucial importance. Traditional powder metallurgy methods for producing Mo-Si targets often yield compositional inhomogeneities, coarse grain structures, and cracking due to density differences between Mo and Si phases and the exothermic reaction between molybdenum and silicon. This poses significant challenges in target fabrication. This study proposes a systemic “powder pre-alloying + hot-press sintering” process. Using a mixed powder with a molybdenum-silicon atomic ratio of 1:9 as raw material, systematically investigating the effect of heat treatment temperature on molybdenum-silicon alloying. The optimal temperature was determined to be 1350 °C with a 2-h soak. The phase evolution sequence during the molybdenum-silicon reaction was elucidated as Mo + Si → Mo3Si + Si → Mo5Si3 + Si → MoSi2. Further investigations revealed that the resulting Si-MoSi2 alloy powder exhibits brittle-brittle system characteristics. Mechanical ball milling continuously refines the particles, increasing the surface energy and density of microdefects in the powder, which helps improve the powder’s sintering activity, enabling the successful production of molybdenum-silicon targets with a relative density no less than 99% and markedly improved microstructural uniformity.