There is provided a process and its system for fabricating plasma with feedback control on plasma density. This process uses a heterodyne millimeter wave interferometer as a sensor to measure the plasma density in the process container and the plasma density that is needed in the plasma fabricating process, and then provides real-time information of the measurements to a digital control device which makes numerical calculations and then drives the RF power generator to change the RF output power so as to enable the plasma density in the plasma fabricating process to be close to the expected plasma density. The conventional operation parameter method is to control air pressure, RF power, gas flow quantity, temperature and so on. However, it does not control the plasma parameter that has the most direct influence on the process. Therefore, this method cannot guarantee that, in the process of fabricating wafers, different batches of wafers will be operated under similar process plasma conditions. The present invention provides a process plasma source that can be directly controlled so as to obtain process plasma source of steady quality.
A method for plasma ion implantation of a substrate includes providing a plasma ion implantation system having a process chamber, a source for producing a plasma in the process chamber, a platen for holding a substrate in the process chamber, an anode spaced from the platen, and a pulse source for generating implant pulses for accelerating ions from the plasma into the substrate. In one aspect, a parameter of an implant process is varied to at least partially compensate for undesired effects of interaction between ions being implanted and the substrate. For example, dose rate, ion energy, or both may be varied during the implant process. In another aspect, a pretreatment step includes accelerating ions from the plasma to the anode to cause emission of secondary electrons from the anode, and accelerating the secondary electrons from the anode to a substrate for pretreatment of the substrate.
A sterilization system and method applies low frequency power to a plasma within a vacuum chamber to remove gas or vapor species from an article. The sterilization system includes a switching module adapted to pulsate the low frequency power applied to the plasma and a low frequency power feedback control system for controllably adjusting the low frequency power applied to the plasma. A power monitor is adapted to produce a first signal indicative of the low frequency power applied to the plasma within the vacuum chamber. A power control module is adapted to produce a second signal in response to the first signal from the power monitor, and a power controller is adapted to adjust, in response to the second signal, the low frequency power applied to the plasma to maintain a substantially stable average low frequency power applied to the plasma while the article is being processed.
A sterilization system applies power to a plasma within a chamber to remove gas or vapor species from an article. The sterilization system includes a power feedback control system for controlling the power applied to the plasma. The power feedback control system includes a current monitor adapted to produce a first signal indicative of a current applied to the plasma within the chamber. The power feedback control system further includes a voltage monitor adapted to produce a second signal indicative of a voltage applied to the plasma within the chamber. The power feedback control system further includes a power control module comprising a programmable digital signal processor. The digital signal processor is adapted to receive and process the first signal and the second signal by multiplying the current and the voltage and producing a third signal indicative of the product of the current and the voltage. The power feedback control system further includes a plasma generator coupled to the power control module and adapted to adjust, in response to the third signal, the power applied to the plasma within the chamber.
The present invention provides a power feedback control system for controllably maintaining a predetermined average power value of a power applied to a plasma of a sterilization system. The power has a frequency of from 0 to approximately 200 kHz. The power feedback control system includes a power monitor including a current monitor and a voltage monitor. The current monitor is adapted to produce a first signal indicative of a current applied to the plasma. The voltage monitor is adapted to produce a second signal indicative of a voltage applied to the plasma. The power monitor is adapted to produce a third signal in response to the first signal and second signal. The third signal is indicative of the power applied to the plasma. The power feedback control system further includes a power control module adapted to produce a fourth signal in response to the third signal from the power monitor and to a reference signal corresponding to the predetermined average power value. The power feedback control system further includes a power controller adapted to adjust, in response to the fourth signal, the power applied to the plasma to maintain the predetermined average power value of the power applied to the plasma.
A fault handling algorithm processes a plurality of fault status signals from a sputtering system in a period of time to generate at least one command signal for affecting the operation of a power generator.
