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US 8,772,054 B2Granted
Focus control method for photolithography
AssigneeTaiwan Semiconductor Manufacturing Company, Ltd.
InventorsJen-Pan Wang, Chien-Hsuan Liu, Ching-Hsien Chen, Chao-Chi Chen
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Abstract
A method comprises providing a semiconductor substrate having at least one layer of a material over the substrate. A sound is applied to the substrate, such that a sound wave is reflected by a top surface of the layer of material The sound wave is detected using a sensor. A topography of the top surface is determined based on the detected sound wave. The determined topography is used to control an immersion lithography process.
Claims15
A method comprising:
- (a) providing a semiconductor substrate having at least one layer of a material over the substrate;
- (b) applying sound to the substrate, such that a sound wave is reflected by a top surface of the layer of material;
- (c) detecting the sound wave using a sensor;
- (d) determining a topography of the top surface based on the detected sound wave;
- and
- (e) using the determined topography to control an immersion lithography process.
3 more elements
A method comprising:
- (a) providing a semiconductor substrate having an inter-metal dielectric layer with a plurality of metal patterns, and a layer of photoresist over the inter-metal dielectric layer;
- (b) applying sound to the substrate, such that a sound wave is reflected by a top surface of the layer of photoresist;
- (c) using a sensor to detect the sound wave;
- and
- (d) determining a topography of the top surface based on the detected sound wave, with sufficient precision to measure intra-field variations in surface height;
- (e) adjusting a focus of a photolithography tool and an energy level of a beam of the photolithography tool, based on the determined topography;
- and
- (f) exposing the photoresist after adjusting the focus and energy level.
5 more elements
Dependencies are inferred from the claim text.