Method of measuring concentration of Fe in p-type silicon wafer and SPV measurement apparatus
AssigneeSumco Corporation
InventorsShinya Fukushima, Takehiro Tsunemori
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Abstract
Provided is a method of measuring the concentration of Fe in a p-type silicon wafer by an SPV method enabling improvement in the measurement accuracy for Fe concentrations of 1×109/cm3 or less. The method of measuring the concentration of Fe in a p-type silicon wafer includes measuring an Fe concentration in the p-type silicon wafer based on measurement using an SPV method. The measurement is performed in an atmosphere in which the total concentration of Na+, NH4+, and K+ is 1.750 μg/m3 or less, and the total concentration of F−, Cl−, NO2−, PO43−, Br−, NO3−, and SO42− is 0.552 μg/m3 or less.
Claims5
A method of measuring a concentration of Fe in a p-type silicon wafer based on measurement by an SPV method,
- wherein the measurement is performed in an atmosphere in which a total concentration of Na+, NH4+, and K+ is 1.750 μg/m3 or less, and a total concentration of F−, Cl−, NO2−, PO43−, Br−, NO3−, and SO42− is 0.552 μg/m3 or less.
An SPV measurement apparatus for measuring a concentration of Fe in a p-type silicon wafer based on measurement by an SPV method, the apparatus comprising:
- a measurement stage on which the p-type silicon wafer is placed in the SPV measurement;
- an optical module by which the p-type silicon wafer is illuminated with light;
- a probe used to measure a capacitance formed between a capacitive sensor provided on a front end of the probe and a surface of the p-type silicon wafer;
- a lock-in amplifier that amplifies and detects an SPV signal corresponding to the capacitance measured with the probe;
- a calibration chip for reducing measurement error;
- a dissociation stage on which the p-type silicon wafer is placed when subjected to a process of dissociating Fe—B pairs in the p-type silicon wafer;
- a flash lamp for dissociating the Fe—B pairs in the p-type silicon wafer;
- a robot arm transferring and delivering the p-type silicon wafer to and from the measurement stage and the dissociation stage;
- a robot controller for controlling the robot arm;
- a first housing receiving the measurement stage, the probe, and the calibration chip;
- a second housing receiving the optical module and the lock-in amplifier;
- a third housing receiving the dissociation stage and the flash lamp;
- and
- a fourth housing receiving the robot arm and the robot controller,
- wherein a first chemical filter and a second chemical filter are provided in upstream air flows of the first housing and the third housing, respectively, and a total concentration of Na+, NH4+, and K+ and a total concentration of F−, Cl−, NO2−, PO43−, Br−, NO3−, and SO42− in an atmosphere inside each of the first housing and the third housing are set to 1.750 μg/m3 or less and 0.552 μg/m3 or less, respectively.
Dependencies are inferred from the claim text.