Confocal Fluorescence Detector

Fluorescent compounds in quartz crucibles used for silicon crystallization can contaminant the semiconductor material. These contaminants migrate through the quartz during the heating and cooling cycles, eventually bringing the fluorophores to the surface and contaminating the molten silicon. Traditionally, a representative crucible is destroyed to determine the depth of the fluorescent material. Confocal fluorescence detection can be used to determine the depth of the fluorescent contaminant without destroying the crucible. By gradually altering the source focal point and simultaneously recording the fluorescence response and source scattering, a fluorescence depth profile can be created, indicating the precise depth of the fluorescent contaminants.

System Features

• A non-destructive, non-contact method for the detection of fluorescent contaminants in quartz or glass.
• Simultaneous measurement of the fluorescence and light scattering for calculation of the fluorescence depth profile. The distance of the fluorescent contaminant from the surface can be readily calculated.
  

Fluorescent Depth Profiles of Quartz Plates	Excellent Correlation to the destructive test results
Measurement results for detection of fluorescent contaminants in several quartz samples. Fluorescence impurities in the quartz plates were found at depths of 0.454, 1.092, 2.060 and 3.240 mm by the destructive test method. Measurements by the CFD-102 produce the fluorescence depth profiles indicating the presence of fluorescent contaminants at depths of 0.32, 0.72, 1.36 and 2.12 mm, respectively. The confocal fluorescence measurement demonstrates excellent correlation to the destructive test results.

Specifications