Surface contamination analyzer for semiconductor wafers, method used therein and process for fabricating semiconductor device
A semiconductor wafer is radiated with an electron beam so that the inelastic scattering takes place in the narrow region, and current flows out from the narrow region; the amount of current is dependent on the substance or substances in the narrow region so that the analyst evaluates the degree of contamination on the basis of the substance or substances specified in the narrow region.
1. A method for investigating contamination of a target region of a semiconductor wafer, the method comprising:
irradiating the target region with an electron beam;
measuring the amount of current generated from the semiconductor wafer in response to the irradiating the target region with the electron beam; and
comparing the amount of current generated in response to the irradiating of the electron beam with a reference current to determine a difference therebetween to detect one or more contaminates on or in the target region.
2. The method of claim 1 wherein the reference current is generated in response to irradiating a region of a reference wafer with an electron beam.
3. The method of claim 1 further including determining a degree of contamination on or in the target region using (1) the amount of current generated in response to the irradiating of the electron beam and (2) the reference current.
4. The method of claim 1 further including generating a three-dimensional representation of the degree of contamination using (1) the amount of current generated in response to the irradiating of the electron beam and (2) the reference current.
5. The method of claim 1 wherein measuring the amount of current generated in response to irradiating the target region with the electron beam includes:
irradiating the target region with the electron beam at a first incident angle;
measuring the amount of current generated in response to the irradiating the target region with the electron beam at the first incident angle;
irradiating the target region with the electron beam at a second incident angle; and
measuring the amount of current generated in response to the irradiating of the electron beam at the second incident angle.
6. The method of claim 5 further including determining a degree of contamination on or in the target region using (1) the amount of current generated in response to the irradiating of the electron beam at the first incident angle and (2) the amount of a current generated in response to the irradiating of the electron beam at the second incident angle.
7. The method of claim 5 further including generating a three-dimensional representation of the degree of contamination using the amount of current generated in response to the irradiating of the electron beam at the first and second incident angles.
8. The method of claim 1 further including removing at least one contaminant from the target region after detecting at least one contaminant on or in the target region.
9. The method of claim 1 further including evaporating at least one contaminant from the target region after detecting the at least one contaminant on or in the target region.
10. The method of claim 1 further including: heat treating the wafer to remove at least one contaminant on or in the target region; and thereafter, irradiating the target region with the electron beam; and measuring the amount of current generated in response to the irradiating of the electron beam.
11. The method of claim 1 further including: measuring the amount of current generated in response to the irradiating the target region with the electron beam when the wafer is at a first temperature; and measuring the amount of current generated in response to the irradiating the target region with the electron beam when the wafer is at a second temperature.
12. The method of claim 11 further including detecting a difference between the amount of current generated in response to irradiating the target area with the electron beam at the first temperature and the amount of current generated in response to irradiating the target area with the electron beam at the second temperature.
13. The method of claim 12 further including generating a three-dimensional representation of a degree of contamination using the amount of current generated in response to the irradiating of the electron beam at the first and second temperatures.