Dry etching apparatus
AssigneeSeiko Epson Corporation
InventorMasaharu Yachi
Life of this patent
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Abstract
Plasma light beams emitted from a plurality of monitoring areas on a wafer are introduced via windows and optical fibers, respectively, and detected by a detector. The detector determines etching end times of the respective monitoring areas. A calculating section calculates a maximum allowable etching end time based on the first-determined etching end time and a predetermined uniformity standard. If the etching ends of all the monitoring areas have not been determined at the time point of the calculated maximum allowable etching end time, a controller immediately stops the etching process.
Claims3
A dry etching method in which gas introduced into a chamber is ionized to become plasma to etch a layer formed on a semiconductor wafer, comprising the following steps:
- providing a plurality of monitoring areas on the wafer;
- detecting the intensity of light beams emanating from said plurality of monitoring areas, the intensity of said light beams representing a thickness of the layer at the respective monitoring areas;
- determining etching end times of the respective monitoring areas based on the detected intensity of said light beams;
- calculating etching parameters including a uniformity of etching rate in said monitoring areas based on the determined etching end times and a thickness of said layer;
- and
- controlling an etching process based on the calculated etching parameters so that subsequent wafers are etched within said uniformity of etching rate.
Dependencies are inferred from the claim text.