Etch amount detection method, etching method, and etching system
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Abstract
This invention accurately detects an etch amount of an etching target layer irrespective of a type of a mask layer. A light La is reflected by an upper surface of a photoresist mask layer 316 and a bottom of a hole H. Thereby a reflected light La1 and a reflected light La2 are obtained. The reflected lights La1 and La2 interfere with each other, thereby generating an interference light Lai. A light Lb is reflected by an interface between the photoresist mask layer 316 and a polysilicon film 304, and the upper surface of the photoresist mask layer 316. Thereby a reflected light Lb1 and a reflected light Lb2 are obtained. The reflected lights Lb1 and Lb2 interfere with each other, thereby generating an interference light Lbi. Using the interference lights Lai and Lbi, an etch amount of the polysilicon film 304 is calculated.
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Citations
18 Claims
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1-12. -12. (canceled)
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13. An etching system for carrying out an etching process to an etching target layer on an object to be processed while using a patterned mask layer as a mask, the system comprising:
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a light source which irradiates a first light having a first wavelength, which does not propagate the mask layer, and a second light having a second wavelength, which is different from said first wavelength and propagates the mask layer, onto said object to be processed; a light detection section which detects a first interference light generated by interference of a first reflected light obtained when said first light is reflected by a surface of said mask layer with a second reflected light obtained when said first light is reflected by a bottom of an etching target portion etched of said etching target layer, and which detects a second interference light generated by interference of a third reflected light obtained when said second light is reflected by the surface of said mask layer with a fourth reflected light obtained when said second light is reflected by an interface between said mask layer and said etching target layer; and an operation section which calculates an etch amount of said etching target portion based on said first interference light and said second interference light. - View Dependent Claims (14, 15, 16, 17, 18)
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Specification