NOVELTY - The method involves etching a metal layer through a patterned mask layer (106). The patterned mask layer is removed by using a plasma formed from process gas comprising oxygen and carbohydrate i.e. ethylene (108). A remaining portion of the patterned mask layer is removed by using the plasma formed from the process gas. Flow rate ratio of oxygen to carbohydrate is adjusted to facilitate control over critical dimension of features formed by the patterned mask layer.    USE - Method for processing a semiconductor substrate. Uses include but are not limited to a silicon substrate, a III-V compound substrate, a silicon germanium substrate, an epi-substrate, a silicon-on-insulator substrate, a display substrate e.g. LCD, plasma display, electro luminescence lamp display, LED substrate, solar cell array and solar panel, a semiconductor wafer e.g. 200 mm silicon wafer and 300 mm silicon wafer, and a partially fabricated semiconductor device e.g. Logic, dynamic RAM and flash memory device.    ADVANTAGE - The method enables remaining antireflective layer and photoresist removed by exposing the substrate to the plasma formed from the process gas, so that an inclusion of ethylene in the plasma allows for a high bias power to be provided, which increases the rate of etch and residue removal without damaging the metal materials, and provides higher etch selectivity between etch residue and an underlying metal layer, thus facilitating antireflective layer and photoresist residue removal without undesirably etching the underlying metal layer and providing greater control over critical dimension of openings.    DESCRIPTION OF DRAWING(S) - The drawing shows a flow diagram of a method for processing of semiconductor substrate.    Method for processing semiconductor substrate (100)    Step for providing substrate with metal layer, antireflective layer and photoresist layer (102)    Step for etching pattern into antireflective layer (104)    Step for etching metal layer through patterned mask layer (106)    Step for removing patterned mask layer using plasma formed from process gas (108)