injected into the chamber 52 through the gas inlet 54 from a gas storing unit not shown and exhausted from the chamber 52 through the gas outlet 56 the apparatus 50 may be a dry etching apparatus or a plasma etching apparatus further the apparatus 50 may be a chemical vapor deposition cvd apparatus or a plasma enhanced chemical vapor deposition pecvd apparatus in addition the chamber 52 includes a lower electrode 62 and an upper electrode 58 spaced apart from each other a substrate 64 is loaded on the lower electrode 62 inside the chamber 52 and the substrate 64 for example may include a thin film to be patterned by an etching process in particular the lower electrode 62 is connected to an outer power supplier 63 which may be located outside the chamber 52 and may apply a radio frequency rf power to the lower electrode 62 further the space between the lower electrode 62 and the upper electrode 58 often is referred to a reaction region in particular the upper electrode 58 is grounded and includes a plurality of injection nozzles 60 for injecting the gases provided through the gas inlet 54 the injection nozzles 60 may be arranged in a matrix manner across the upper electrode 58 the chamber 52 further includes gas injection plates 65 66 and 67 disposed over the upper electrode 58 in particular each of the gas injection plates 65 66 and 67 includes a plurality of nozzles not shown for evenly distributing the gases injected through the gas inlet 54 the number of gas injection plates 65 66 and 67 may vary based on demands such that the apparatus 50 may have at least one gas injection plate.