Patent ID: 7144521
Filing Date: 2006-12-05
Classification: H01J,H01L

Abstract:
1. A method for etching a high aspect ratio feature through a mask into a layer to be etched over a substrate, comprising: placing the substrate in a process chamber, which is able to provide RF power at a first frequency, a second frequency different than the first frequency, and a third frequency different than the first and second frequency; providing an etchant gas to the process chamber; providing a first etch step where the first frequency is at a first power level, the second frequency is at a second power level, and the third frequency is at a third power level, wherein the first power and at least one of the second or the third power are greater than zero, wherein the first etch etches a feature in the layer to be etched to a first depth; and providing a second etch step where the first frequency is at a fourth power level, the second frequency is at a fifth power level, and the third frequency is at a sixth power level, wherein at least one of the fourth and sixth powers is greater than zero and the fifth power is greater than zero, and wherein a condition is selected from the group of the first power not being equal to the fourth power and the third power not being equal to the sixth power, wherein the second etch etches the feature in the layer to be etched to a second depth greater than the first depth.