Device for etching the periphery edge of a substrate and method for controlling etching thereof

A method for controlling etching of substrate edge using a substrate edge etching apparatus,

• the substrate edge etching apparatus comprising:
• a substrate support assembly having a horizontally rotatable chuck base, chuck pins disposed on top of the chuck base to support a substrate, a purge gas inlet hole extending from an underside center of the chuck base to an interior of the chuck base in an upward and downward direction thereof, and a purge gas outlet hole extending radially and horizontally from the purge gas inlet hole and then extending upwardly to penetrate top of the chuck base near the substrate edge;
• a purge gas supply assembly for supplying a purge gas to the purge gas inlet hole;
• a chemical liquid supply unit for supplying a chemical liquid to top of the substrate;
• a bowl assembly having bowls surrounding the periphery of the substrate support assembly and configured to be able to ascend and descend;
• and
• a fan filter unit spaced apart from top of the substrate support assembly,
• wherein etching of the underside of the substrate is performed while rotating the chuck base in a state where the substrate is reversely located on the chuck base and thereby a treatment surface on which a circuit pattern is formed faces toward the top of the chuck base,
• wherein while a chemical liquid is supplied to top of the substrate, purge gas introducing from the underside center of the chuck base through the purge gas inlet hole is supplied to underside of the substrate near the substrate edge through the purge gas outlet hole, thereby radial etched width of the peripheral edge of the underside of the substrate is determined by a balance between escape force of the chemical liquid due to supply of the purge gas and surface tension of the chemical liquid,
• wherein if the etched width is less than a given reference value, the flow rate of the purge gas is decreased, and if the etched width is more than the given reference value, the flow rate of the purge gas is increased, so that the etched width can be adjusted to the given reference value.