Abstract: The present disclosure provides a semiconductor process apparatus and a plasma ignition method. The semiconductor process apparatus includes a reaction chamber, an air inlet assembly configured to introduce the reaction gas into the reaction chamber, an upper electrode assembly configured to excite the reaction gas into the plasma, a monitor configured to monitor the electromagnetic radiation intensity of the plasma in the reaction chamber when the plasma is ignited, a controller configured to determine whether the electromagnetic radiation intensity monitored by the monitor reaches the preset intensity, if yes, determine that the plasma ignition is successful, and after the plasma ignition is successful, control the upper electrode assembly to perform the impedance matching of the first preset duration. In the present disclosure, the consistency of the process results may be improved to improve the uniformity of the products.