Patent ID: 6200822
Filing Date: 2001-03-13
Classification: H01J,H01L

Abstract:
A method for detecting a transition between different materials in a semiconductor structure, wherein the transition is detected during alternating etching steps and at least one of covering steps and deposition steps which are provided for anisotropic depthwise etching of patterns, wherein the etching steps, the covering steps and the deposition steps are performed using a plasma, the method comprising the steps of:a) determining a first start of each of the etching steps by measuring an intensity of at least one specific substance contained in the plasma, the first start being determined using a synchronization signal of an etching machine and when the intensity reaches a characteristic threshold value;b) when the intensity reaches the characteristic threshold value, initiating a second start of a delay time period, the delay time period being longer than a time of a first concentration maximum signal of the etching steps, the second start being detected using the synchronization signal of the etching machine;c) determining a second concentration maximum signal of the etching steps after the delay time period elapses; andd) determining whether the second concentration maximum signal of the etching steps is above or below a value to detect the transition between the different materials.