Non-Destructive Method to Measure the Defect Free Zone In Situ
Original Publication Date: 1982-May-01
Included in the Prior Art Database: 2005-Feb-09
Semiconductor products use silicon wafers coming from crystals pulled by the Czochralski method. The particularity of these crystals is contamination by oxygen (10/17/ to 10/18/ at/cm/3/). During subsequent heat treatments of the semiconductor processes, the oxygen precipitates and, consequently, defects are generated which contribute to the gettering effect. Near the active face, the oxygen concentration decreases by out-diffusion in lowering the defect formation. A zone with a very low density of defects is measurable beneath the active face.