Large-area ECR processing plasmas have been developed. Magnetic fields are composed of permanent magnets located along dosed lines, inverting the polarity line by line, At first a new type of microwave launching system which consists of a dielectric plate and metal bars was tested, by using a discharge chamber of circular geometry in a diameter of 30 cm. It was verified that the launcher was useful in the production of a large-area plasma in a wide range of gas pressures. By using this type of launcher, a plasma in a rectangular geometry with dimensions of 40 X 50 cm was generated. Basic data which lead to the solution used to obtain a large rectangular uniform plasma (uniformity better than +/-5%) were obtained.