JPS54115061A - Inspection method of semiconductor wafer by infrared rays - Google Patents

Abstract

PURPOSE:To inspect the impurity concentration distribution in wafer with good accuracy, by using the wave length variable type infrared ray laser as light source, and setting the wave length of laser light to the wave length region present in the absorbing band of molecules or atoms desired. CONSTITUTION:The wave length variable type semiconductor laser is taken as a light source, and the wave length of emitted light is varied by performing variable control of the current flowing to the laser. The laser light passed through the test piece 5 is collected with the lens 6 and it is incident to the detector 7, converting into to electric signal and inputting to the divider 8. On the other hand, the reflection light reflected with the semitransparent mirror 4 is collected with the lens 10 and incident to the detector 11, converted into electric signal, and inputted to the divider 8. Further, the output signal operationally processed is fed to the Y terminal of the X-Y recorder 12. On the other hand, the signal in synchronizing with movement of the test piece 5 is fed to the X terminal of the X-Y recorder 12 for the synchronous signal generating circuit. Thus, the spectrum absorption curve 14 of the test piece 5 is displayed.