Patent ID: 7173435

Claim:
A measurement device for measuring a thickness of a film layer over a substrate, comprising: a resonant cavity having an open side, wherein at least a segment of a face around the open side contacts at least a portion of a surface of the film layer and the substrate acts as a wall of the resonant cavity; a microwave source to generate a super high frequency electromagnetic wave signal coupled to a first end of the resonant cavity, wherein the microwave source comprises: an oscillator to generate a first electrical signal having a frequency that is substantially lower than a resonant frequency of the resonant cavity, wherein the oscillator is located at a remote location from the resonant cavity to thermally isolate the oscillator from the resonant cavity; and a frequency multiplier coupled to the oscillator to receive the first electrical signal and convert the first electrical signal into a second electrical signal by increasing the frequency by a predetermined factor, wherein the frequency multiplier is collocated with the resonant cavity; a signal detector to sense an output power of the signal coupled to a second end of the resonant cavity; and a processor to correlate the output power to the thickness.