A microelectronic device is formed using a fabrication tool such as a plasma thin film deposition tool or a plasma etch tool. A smart in-situ chamber clean begins with an initial plasma. A first physical signal is measured while the initial plasma is in progress, and the measured value is stored in a memory unit. A process controller retrieves the measured value, uses it to compute a deposition estimate parameter, and determines when the deposition estimate parameter meets a minimum deposition criterion. When the result of the determination is TRUE, the smart in-situ chamber clean terminates without an in-situ cleaning of the process chamber. When the result of the determination is FALSE, the smart in-situ chamber clean proceeds with an in-situ cleaning. The in-situ cleaning may be a continuation of the initial plasma. Subsequently, the microelectronic device is processed in the fabrication tool.