Patent ID: 8253930

Claim:
An absorption spectrometric apparatus for semiconductor production process, comprising: a flow passageway switching mechanism connected to a discharging flow passageway of a processing chamber for a semiconductor production process; and a multiple reflection type moisture concentration measuring absorption spectrometric analyzer connected to the discharging flow passageway via the flow passageway switching mechanism, and including a cell that passes a process gas discharged from the discharging flow passageway therethrough and an optical system that allows a laser beam from a laser light source to undergo multiple reflection within the cell and detects alight absorbancy change by the process gas within the cell, so as to measure a moisture concentration within the process gas, wherein the flow passageway switching mechanism connects the discharging flow passageway by switching between a measuring flow passageway through which the gas is discharged by passing through the cell of the absorption spectrometric analyzer and a bypass flow passageway through which the gas is discharged without passing through the cell.