Processes and device for the deposition of films on substrates
View Patent ↗It is in the object of the present invention to improve current deposition processes and devices for the fabrication of multilayer systems to better control the energy contribution at different stages of the deposition. This is achieved by depositing films by sputtering in a scheme providing for thermalized particles. One can get thermalized particles by choosing the working gas pressure and the distance between target and substrate to result in a mean free path of particles smaller than the distance between target and substrate or to result in a product of pressure and distance being larger than 2.0 cmPa.
1. A process for the deposition of films on substrates, comprising:
a step of sputtering or magnetron sputtering of one layer of Mo or Si on another layer underlying said one layer of Mo or Si or on a substrate for the fabrication of a reflective Mo/Si multilayer system for the extreme ultraviolet wavelength range, wherein a distance between a target and a substrate is larger than 25 cm, and
wherein during said sputtering of said one layer a working gas pressure is regulated in a first step to a first pressure value and is decreased in one subsequent step to a second pressure value lower than the first pressure value,
so that for the first pressure value the mean free path of particles is smaller than the distance between the target and the substrate and for the second pressure value the mean free path of particles is larger than the distance between the target and the substrate,
leading to a suppression of intermixing between said one layer and said another layer or said substrate for the first pressure value and enabling to control the growing film's roughness of said one layer for the second pressure value.
2. A process as claimed in claim 1 , wherein said one layer has a total thickness of about 1.5 nm for Mo and 4.5 nm for Si and wherein said first step of sputtering ends at a thickness of about 0.5 nm for Mo and 0.5 nm for Si.
3. A process as claimed in claim 1 , wherein said first pressure value is set between about 6×10 −4 mbar and about 8×10 −4 mbar and said second pressure value is set between about 1×10 −4 mbar and about 3×10 −4 mbar.
4. A process as claimed in claim 2 , wherein said first pressure value is set between about 6×10 −4 mbar and about 8×10 −4 mbar and said second pressure value is set between about 1×10 −4 mbar and about 3×10 −4 mbar.