A method of processing a wafer includes a wafer preparing step of preparing a measurement wafer and a product wafer, a measurement etching step of supplying a gas in a plasma state to first areas of the measurement wafer that correspond to streets thereon to form grooves in the measurement wafer, a measuring step of demarcating a plurality of concentric areas in an array from a center to an outer circumference of the measurement wafer, and measuring depths of the grooves in the respective concentric areas, a thickness adjusting step of adjusting a thickness of the product wafer such that the product wafer is progressively thinner in areas thereof that correspond to the areas of the measurement wafer where the grooves are shallower, and an etching step of supplying a gas in a plasma state to second areas of the product wafer that correspond to streets thereon.