Method and system for controlling the uniformity of a ballistic electron beam by RF modulation
AssigneesTokyo Electron Limited, Texas Instruments Incorporated
InventorsLee Chen, Ping Jiang
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Abstract
A method and system for treating a substrate using a ballistic electron beam is described, whereby the radial uniformity of the electron beam flux is adjusted by modulating the source radio frequency (RF) power. For example, a plasma processing system is described having a first RF power coupled to a lower electrode, which may support the substrate, a second RF power coupled to an upper electrode that opposes the lower electrode, and a negative high voltage direct current (DC) power coupled to the upper electrode to form the ballistic electron beam. The amplitude of the second RF power is modulated to affect changes in the uniformity of the ballistic electron beam flux.
Claims17
A method of etching a thin film on a substrate using a plasma processing system having a ballistic electron beam, comprising:
- disposing said substrate on a substrate holder in said plasma processing system;
- coupling direct current (DC) power to an electrode within said plasma processing system in order to create said ballistic electron beam from secondary electrons generated from ions bombarding said electrode during plasma generation;
- coupling alternating current (AC) power to said electrode having DC power coupled thereto and to said substrate holder, in order to form plasma in said plasma processing system;
- modulating two or more of a frequency, a duty cycle and an amplitude of said AC power to said electrode having DC power coupled thereto in order to control uniformity of the ions bombarding said electrode and thereby adjust the spatial distribution of said secondary electrons emitted from said electrode and the electron beam flux for said ballistic electron beam;
- and
- etching the thin film with the plasma and the ballistic electron beam having an adjusted spatial distribution of electron beam flux.
Dependencies are inferred from the claim text.