Method for controlling the extent of notch or undercut in an etched profile using optical reflectometry
First Claim
1. A method for controlling lateral etching during an etching process, comprising:
- laterally etching a lower layer of a stack of layers;
radiating a spectrum of light over said lower layer being etched and an area over said stack of layers proximate to said lower layer being etched;
measuring intensity of light reflected from at least one of said stacked layers positioned lateral to said lower layer being etched; and
ceasing said etching process upon measuring a predetermined metric associated with said intensity of reflected light from said at least one of said stacked layers.
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Accused Products
Abstract
A method and apparatus for controlling lateral etching during an etching process. The method and apparatus includes laterally etching a lower layer of a stack of layers in a processing chamber, where an endpoint detection system radiates a spectrum of light over the lower layer being etched and an area over the stack of layers proximate to the lower layer being etched. The intensity of light reflected from at least one of the stacked layers positioned lateral to the lower layer being etched is then measured. An endpoint detection system terminates the etching process upon measuring a predetermined metric associated with the intensity of reflected light from the at least one of the stacked layers.
13 Citations
31 Claims
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1. A method for controlling lateral etching during an etching process, comprising:
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laterally etching a lower layer of a stack of layers;
radiating a spectrum of light over said lower layer being etched and an area over said stack of layers proximate to said lower layer being etched;
measuring intensity of light reflected from at least one of said stacked layers positioned lateral to said lower layer being etched; and
ceasing said etching process upon measuring a predetermined metric associated with said intensity of reflected light from said at least one of said stacked layers. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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14. A method for controlling lateral etching of a notch in a transistor gate layer of a transistor during an etching process, said transistor comprising a stack of layers disposed below said transistor gate layer, said method comprising:
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laterally etching a lower portion of said transistor gate layer;
radiating a selected wavelength of light over an upper surface of said transistor gate;
measuring intensity of light reflected from the upper surface of said transistor gate and a layer of said stack of layers positioned beneath said transistor gate; and
ceasing said etching process upon measuring a predetermined metric associated with said intensity of reflected light from said at least one of said stacked layers. - View Dependent Claims (15, 16, 17, 18)
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19. Apparatus for controlling lateral etching during an etching process, comprising:
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means for laterally etching a lower layer of a stack of layers;
means for radiating a spectrum of light over said lower layer being etched and an area over said stack of layers proximate to said lower layer being etched;
means for measuring intensity of light reflected from at least one of said stacked layers positioned lateral to said lower layer being etched; and
means for ceasing said etching process upon measuring a predetermined metric associated with said intensity of reflected light from said at least one of said stacked layers. - View Dependent Claims (20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31)
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Specification