Plasma Damage Mechanism of Electron Beam Curing Process for Spin on Dielectrics

This letter presents the plasma damage mechanism of electron beam curing process for spin on dielectrics. Device damage is studied using the antenna gate metal-oxide-semiconductor field-effect transistor (MOSFET) in terms of the threshold voltage variation as a function of electron beam conditions such as ambient and cathode voltage. Threshold voltages of nMOSFET are decreased by an electron beam curing process without antenna ratio dependency. The electron energy and interlayer dielectric thickness between active devices and metal layers largely affect the variation of threshold voltage. From the experimental results, it is concluded that device damage induced by an electron beam curing process is characterized as radiation damage rather than electron charging damage. For the damage free electron beam curing process, it is essential to control the penetration depth of high-energy electrons by adjusting the cathode voltage while considering the dielectric thickness over active devices.