Sacrificial hardmask ALD with hydrogen peroxide: comparative study of low temperature growth and film characteristics for TiO2 and Al2O3

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Sacrificial hardmask ALD with hydrogen peroxide: comparative study of low temperature growth and film characteristics for TiO2 and Al2O3

Continued reliance on 193nm immersion lithography with multiple patterning is becoming much more difficult as line widths decrease. With the use of Self-Aligned Quadruple patterning and related patterning schemes, it is critical to minimize variability, where high quality films must be deposited and etch rates must be very precise. To this end, a better understanding of spacer material properties must be obtained. Initial work has been performed to examine the resulting film properties for TiO2 and Al2O3 spacer materials deposited by low temperature ALD with the use of various oxidants (H2O2, H2O, O3). Improved film quality has been demonstrated for films deposited with H2O/H2O2 mixtures used as the oxidant. Key to advanced patterning applications is that improved etch resistance is achieved for both Metal Oxide materials. Also significant with regard to multiple patterning is that higher growth rates are obtained at reduced temperatures, enabling lower process temperatures for underlying sensitive materials. The all thermal nature of these deposition methods points toward improved film conformality on 3-Dimensional structures. Improved etch rates and improved electrical properties reflect overall improvements in Metal Oxide dielectric film quality with the use of Hydrogen Peroxide.