Abstract: A content addressable memory (CAM) device that includes a plurality of CAM cells coupled to a match line to affect a voltage of the match line in response to data values of the CAM cells and comparand data being in a predetermined logical relationship, and a match detect circuit coupled to the match line and adapted to differentially compare the voltage of the match line with a fixed reference voltage and, in response, generate an output signal having two or more logical states corresponding to the states of the predetermined logical relationship between the data value and the comparand data.

Abstract: A plasma etching endpoint detection system monitors two optical wavelengths during etching of a non-opaque dielectric film. A controller coupled to the optical monitoring equipment generates an endpoint detection signal corresponding to a predefined mathematical combination of the monitored intensity of light at the first wavelength and the monitored intensity of light at the second wavelength. When the endpoint detection signal crosses a threshold level, the etching of the dielectric layer is stopped. In a preferred embodiment the two monitored wavelengths differ by approximately a factor of two. More generally, the two monitored wavelengths are selected such that the combined intensity signal has a proportionally smaller false endpoint peak than either of the individual monitored intensity signals.