A method for constructing a magnetoresistive sensor that avoids shadowing effects of a mask structure during sensor definition. The method includes the use of an antireflective coating (ARC) and a photosensitive mask deposited there over. The photosensitive mask is formed to cover a desired sensor area, leaving non-sensor areas exposed. A reactive ion etch is performed to transfer the pattern of the photosensitive mask onto the underlying ARC layer. The reactive ion etch (RIE) is performed with a relatively high amount of platen power. The higher platen power increases ion bombardment of the wafer, thereby increasing the physical (ie mechanical) component of material removal relative to the chemical component. This increase in the physical component of material removal result in an increased rate of removal of the photosensitive mask material relative to the ion mill resistant mask. This avoids the formation of a bulbous or mushroom shaped photoresist mask and therefore, avoids shadowing effects during subsequent manufacturing processes.