EED$f$ and IED$f$ of the non-ambipolar e$^{-}$-beam plasma and their effects on etch

The control of electron shading is crucial in achieving the super-high aspect ratio contact (HARC); precise ion-energy control is essential in the selective etching of lamella diblock copolymers to develop the nano-lines for Direct Self Assembly (DSA). The plasma EED$f$ not only determines the chemistry but also dictates the shading level of the features. The above processes are presented as examples to illustrate the effects of EED$f$ and the surgical surface-excitation by a controlled IED$f$. In addition to demonstrating the methods of achieving a prescribed IED$f$ through external bias, the properties of the non-ambipolar electron plasma (NEP) will be presented. NEP is heated by the non-ambipolar beam-current density in the range of 10s Acm$^{-2}$ through beam-plasma instabilities. Its EED$f$ has a Maxwellian bulk followed by a broad energy-continuum connecting to the most energetic group with energies above the beam-energy and such EED$f$ seems consistent with that required for deep-contact etching. The remnant of the injected electron-beam power terminates at the NEP end-boundary (i.e., wafer) could set up a controllable DC sheath potential resulting in mono-energetic surface excitation by the charge-neutral plasma beam without the application of external bias.\\[4pt] In collaboration with Zhiying Chen, Tokyo Electron America, Inc., Austin, TX 78741.