METHOD AND APPARATUS FOR ETCH RATE STABILIZATION

摘要

A method of consecutively processing a series of semiconductor substrates with minimal etch rate variation. The method includes steps of (a) placing a semiconductor substrate on a substrate support in a plasma etching chamber, (b) maintaining a vacuum in the chamber, (c) etching an exposed surface of the substrate by supplying an etching gas to the chamber and energizing the etching gas to form a plasma in the chamber, (d) removing the substrate from the chamber; and (e) consecutively etching additional substrates in the chamber by repeating steps (a-d), the etching step being carried out by maintaining an amount of reactive gas in contact with an exposed surface of the substrate at a level sufficient to obtain a repeatable rate of etching for each of the substrates processed during repeated step (c). An apparatus useful for carrying out the method includes a plasma etching chamber having a substrate support in an interior thereof and a dielectric member facing the substrate support, a gas supply supplying etching gas into the interior of the chamber, an antenna passing RF energy through the dielectric member, a vacuum pump separated from the interior of the chamber by an adjustable gate valve, and a controller maintaining an amount of reactive gas in contact with an exposed surface of the substrate at a level sufficient to obtain a repeatable rate of etching for each substrate processed in the chamber during consecutive single substrate etching of batch of substrates.