Ion implanter in-situ mass spectrometer

Abstract

An apparatus for the in-situ detection of ions in a beam of an ion implanter device includes a mass spectrometer device having inner and outer walls and, a system for generating and directing an ion implant beam through the mass spectrometer device. The mass spectrometer device generates a magnetic field for directing ions of the ion implant beam of a desirable type through an aperture for implanting into a semiconductor wafer, and causing ions of undesirable type to collide with the inner or outer wall. For in-situ detection, a detector device is disposed on the inner and outer walls of the mass spectrometer for detecting the undesirable type of ions deflected. In one embodiment, the detector device comprises electronic sensor devices for detecting a concentration of the undesirable type ions which comprise undesirable elements and compounds. In another embodiment, the detector device comprises Faraday cup devices for detecting a concentration of ions of the undesirable type, or, may comprise a moving Faraday device positioned along tracks disposed respectively along the inner and outer wall, the Faraday being driven for reciprocal movement along a respective track. Data is collected from the sensors corresponding to the positions of undesirable ion detection and is processed, in real-time, during wafer processing. In this manner potential contaminants in the ion implant beam may be determined and corrective action may be taken in response.