초록 ▼

A process monitor which is particularly useful for endpoint detection in plasma etching processes does not require the dedication of a test area on the wafer for endpoint detection and also obviates the need for wafer alignment. An improved optical window which does not significantly perturb the RF

A process monitor which is particularly useful for endpoint detection in plasma etching processes does not require the dedication of a test area on the wafer for endpoint detection and also obviates the need for wafer alignment. An improved optical window which does not significantly perturb the RF fields in the plasma chamber is also disclosed. The apparatus reflects laser energy off an area of the wafer comparable to the area of a typical die and extracts the necessary information from the resulting waveform by means of first and second time derivatives.

대표청구항 ▼

A method for monitoring the change in thickness of an article, subjected to a process which acts upon at least one surface of said article, comprising the steps of: illuminating a portion of said surface with coherent radiation; detecting radiation reflected from said surface and producing an analog

A method for monitoring the change in thickness of an article, subjected to a process which acts upon at least one surface of said article, comprising the steps of: illuminating a portion of said surface with coherent radiation; detecting radiation reflected from said surface and producing an analog signal proportional thereto; wherein said illuminating detecting steps are carried out at more than one location on said surface to produce several analog signals; and identifying points in said analog signals indicative of predetermined changes in thickness.