NOVELTY - Plasma processing apparatus comprises a controller including a prediction equation former which forms a prediction equation of process result in accordance with plasma state data detected with state detector for plasma process simulating a specimen existing state in processing chamber in specimen non-placed state and process result data of specimen input, and storing the prediction equation. The controller predicts the process result of succeeding plasma process in accordance with plasma state data newly acquired via state detector in specimen non-placed state and stored prediction equation.    USE - For physically and chemically processing semiconductor wafers by decomposing process gasses by plasma.    ADVANTAGE - The apparatus is capable of detecting beforehand generation of a working defect and correctly predicting the process result without using a dummy wafer whose surface state is already managed, thus apparatus can be made more inexpensive. The influence of surface contamination can be eliminated and prediction can be made at high precision. If process results are predicted, the state of the apparatus can be grasped more correctly and the process after the recovery work can be made reliably.    DETAILED DESCRIPTION - A plasma processing apparatus comprises:    (1) a processing chamber which performs a plasma process by generating plasma in a specimen placed state and in a specimen non-placed state, including a process gas supplier and a plasma generator;    (2) a state detector which detects a state of plasma in the processing chamber;    (3) an input unit which inputs process result data of a specimen processed in the plasma processing chamber; and    (4) a controller including a prediction equation former which forms a prediction equation of a process result in accordance with plasma state data detected with the state detector for the plasma process simulating a specimen existing state in the processing chamber in the specimen non-placed state and process result data of the specimen input with the input unit and processed by the plasma process in the specimen placed state, and storing the prediction equation.    The controller predicts the process result of a succeeding plasma process in accordance with plasma state data newly acquired via the state detector in the specimen non-placed state and the stored prediction equation. An INDEPENDENT CLAIM is also included for process result prediction method for a plasma processing apparatus,    DESCRIPTION OF DRAWING(S) - The figure is a diagram illustrating a sequence for plasma processing.