When a charged beam is irradiated on a sample, charge up of electric charge of the same polarity as that of the charged beam is built up on the sample surface. In order to neutralize the charge up electric charge, an apparatus for suppressing electrification of sample in charged beam irradiation apparatus is provided in which electric charge of opposite polarity to that of the charged beam is generated near the sample surface to neutralize the charged beam or charge up electric charge on the sample surface. The electric charge for neutralization is generated by admitting elecrtic charge from a plasma generation unit to the vicinity of the sample surface, ionizing gas generated from the sample surface by causing the charged beam to collide the gas or by irradiating electrons from an electron source on the sample surface. Especially when there is a possibility that impurities other than the electric charge for neutralization affect the sample adversely, an impurity generation source is blind folded with a cover so as not to be seen through from the sample and charged beam so that the impurities may be prevented from impinging upon the sample surface or intersecting the charged beam path.
When a plasma is ignited in a plasma generator, an ion beam is made to run in the plasma generator, and in this state, a positive voltage with respective to ground is applied to a plasma production chamber from a DC power source. Secondary electrons are generated when the ion beam collides with a plasma generating gas which flows out of the plasma production chamber into a path of the ion beam. The secondary electrons are led into the plasma production chamber by the positive voltage, and within the plasma production chamber, a plasma ignition is triggered using the secondary electrons led into the plasma production chamber and a radio frequency.
An improved ion beam neutralizer (22) is provided for neutralizing the electrical charge of an ion beam (28) output from an extraction aperture (50). The neutralizer comprises a source of water (52); a vaporizer (54) connected to the source of water; a mass flow controller (56) connected to the vaporizer; and an inlet (60) connected to the mass flow controller. The vaporizer (54) converts water from the source (52) from a liquid state to a vapor state. The mass flow controller (56) receives water vapor from the vaporizer (54) and meters the volume of water vapor output by a mass flow controller outlet (66). The inlet (60) is provided with an injection port (68) located proximate the ion beam extraction aperture (50) and receives the metered volume from the outlet (66). The injection port (68) is positioned near the extraction aperture so that the ion beam and the water vapor interact to neutralize the ion beam. The improved ion beam neutralizer (22) is especially effective in low energy (less than ten kilo-electron volts (10 KeV)) beam applications.
A semiconductor device and a fabrication method are disclosed which are capable of preventing a charge-up phenomenon which occurs during a plasma process, and the semiconductor device includes a center portion of a semiconductor device having a passing through portion and a blocking portion and formed on the center portion of the semiconductor substrate, and a peripheral portion having a pad and a discharging portion formed near the pad and connected with the ground.
When neutralized plasma is generated, the cylindrical electrode 8 is set at a negative potential against the processing chamber 23 by the DC power source 18, so that ions 23 in the neutralized plasma can be collected at the cylindrical electrode 8. Electrons 24 equal to the collected ion charge can be supplied uniformly toward the ion beam 25. Therefore, by allowing the cylindrical electrode to collect ions, the ion collection area can be spread easily, and only by generating neutralized plasma of low density, a sufficient volume of ions can be collected surely from the plasma and a sufficient volume of electrons can be supplied to the ion beam 25 at the same time.
A method and system is provided for cleaning a contaminated surface of a vacuum chamber, comprising means for (i) generating an ion beam (44) having a reactive species (e.g., fluorine) component; (ii) directing the ion beam toward a contaminated surface (100); (iii) neutralizing the ion beam (44) by introducing, into the chamber proximate the contaminated surface, a neutralizing gas (70) (e.g., xenon) such that the ion beam (44) collides with molecules of the neutralizing gas, and, as a result of charge exchange reactions between the ion beam and the neutralizing gas molecules, creates a beam of energetic reactive neutral atoms of the reactive species; (iv) cleaning the surface (100) by allowing the beam of energetic reactive neutral atoms of the reactive species to react with contaminants to create reaction products; and (v) removing from the chamber any volatile reaction products that result. Alternatively, the method and system include means for (i) generating an energetic non-reactive (e.g., xenon) ion beam (44); (ii) directing the non-reactive ion beam toward a contaminated surface (100); (iii) introducing a cleaning gas (70) proximate the contaminated surface, comprised at least partially of a reactive species (e.g., fluorine) component; (iv) dissociating the cleaning gas using the ion beam (44) to create a supply of energetic reactive neutral atoms of the reactive species; (v) cleaning the surface (100) by allowing the energetic reactive neutral atoms of the reactive species to react with contaminants to create reaction products; and (vi) removing from the chamber any volatile reaction products that result.
