Method for generating charged particles
A method for establishing a calibrating standard for wafer inspection includes depositing solid ionized particles of a known size range with an aerosol onto a wafer. The method also includes depositing particles onto a wafer in a deposition chamber by using an aerosol stream and the solid particles suspended in a gas; ionizing the aerosol stream with a negative or positive charge polarity or both by passing the aerosol stream through a non-radioactive ionizer to produce charged particles and supplying such aerosol stream to the deposition chamber.
1 . A method of depositing particles from a source onto a wafer, the wafer being disposed in a deposition chamber, the method comprising:
producing an aerosol stream with solid particles suspended in a gas;
ionizing the aerosol stream with a negative or positive charge polarity or both by passing the aerosol stream through a non-radioactive ionizer to produce charged particles; and
supplying the aerosol stream containing charged particles to the deposition chamber.
2 . The method of claim 1 and further including classifying the ionized particles in a selected size range.
3 . The method of claim 1 wherein the particle ionizer is a corona discharge type ionizer.
4 . The method of claim 1 wherein the particle generator is an electrospray type generator.
5 . The method of claim 2 wherein the particles are classified using an electrostatic type classifier.