The chemical-mechanical polishing (CMP) of products in general and semiconductor wafers in particular is controlled by monitoring the acoustic emissions generated during CMP. A signal is generated with the acoustic emissions which is reflective of the energy of the acoustic emissions. The signals are monitored and the CMP process is adjusted in response to a change in the acoustic emission energy. Changes in the acoustic emission energy signal can be used to determine the end-point for CMP, particularly when fabricating semiconductor wafers for planarizing/polishing a given surface thereof. Long-term changes in the acoustic emission energy signals resulting from process changes including, for example, wear of the polishing pad, can also be detected with the acoustic emission energy signals so that desired or necessary process adjustments, such as a reconditioning of the polishing pad, for example, can be effected or the process can be stopped or an alarm signal can be generated when unacceptable process abnormalities occur.