The ability to etch silicon highly anistropically at active fin heights of 45nm or greater is critical to fin patterning for continued CMOS scaling. Tight control of fin CD and taper is critical toward controlling the device, with particular importance to channel control. In this study we explore the quasi-atomic layer etch (qALE) parameter space in order to better understand the impact of plasma conditions on fin CD, profile, and aspect ratio dependent etch phenomena. A qALE solution is needed to provide a manufacturable solution for a vertical square bottom fin.
In this study a cyclic chlorination (surface modification) + ion bombardment process (modified surface removal) is used to etch Si with a Si3N4 hard mask. Various parameters are explored including bias power, pressure, and time in the ion bombardment step as well as source power, pressure, and time in the chlorination step. With regards to the ion bombardment step, varying time helps to quantify the self-limitation of the etch process, modulating pressure helps to quantify the impact of reduced mean free path and ion density, and modifying source power helps to quantify the impact of changes to ion density. For the chlorination step, varying time helps to quantify the self-limitation of surface modification mechanism, and modifying source power illustrates the impact of Cl radical density on surface modification. These various mechanisms will be explored with the particular view point of how these changes can impact ultimate channel performance.
Extending extreme ultraviolet (EUV) single exposure patterning to its limits is dependent on eliminating its stochastic defectivity. Along with developments in photoresist platforms, the patterning film stack also needs to be considered. The material immediately underneath the photoresist is expected to have significant impact on both lithographic and pattern transfer performance. By designing the resist substrate interface with high EUV absorbance, there is potential to increase the EUV quantum yield of the exposure process. Increasing the selectivity to organic layer offers the opportunity to modulate stochastic defects through etch strategies. This paper will demonstrate the patterning of various chemically amplified resists on a high-Z metal-based hardmask. The potential for dose reduction, higher etch selectivity, and defectivity improvement from a high-Z hardmask will be discussed. Deposition-trim etch techniques will be used for decreasing the transfer of stochastic defects to the underlying substrate. Sub-32nm pitch trench patterning, defectivity, and electrical yield for this patterning stack will be highlighted.
Extending extreme ultraviolet (EUV) single exposure patterning to its limits is dependent on eliminating its stochastic defectivity. Along with developments in photoresist platforms, the patterning film stack also needs to be considered. The material immediately underneath the photoresist is expected to have significant impact on both lithographic and pattern transfer performance. By designing the resist substrate interface with high EUV absorbance, there is potential to increase the EUV quantum yield of the exposure process. This paper will demonstrate the patterning of a chemically amplified resist on a high-Z metal-based hardmask. The potential for dose reduction, higher etch selectivity, and defectivity improvement from a high-Z hardmask will be discussed. Deposition-trim etch techniques will be used for decreasing the transfer of stochastic defects to the underlying substrate. Sub-32nm pitch trench patterning, defectivity, and electrical yield for this patterning stack will be highlighted.
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