System and Method to Align and Measure Alignment Patterns on Multiple Layers
First Claim
1. A system, comprising:
- an alignment system including first and second light sources and a detector that generates a measured signal therefrom;
an object, including,a first layer including a first alignment pattern, anda second layer including a second alignment pattern, the second layer being below the first layer; and
a focusing system that co-focuses on the detector light from the first and second light sources after each has impinged on the respective the first and second alignment patterns,whereby the object is aligned based on the measured signal and wherein the measured signal is generated from the co-focused light from the first and second alignment patterns.
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Accused Products
Abstract
A system and method are used to increase alignment accuracy of feature patterns through detection of alignment patterns on both a surface layer and at least one below surface layers of an object. A first frequency of light, such as visible light, is used to detect alignment patterns on the surface layer and a second frequency of light, such as infrared light, is used to detect patterns one layer below the surface. For example, reflected light of a first frequency and transmitted light of a second frequency are co-focused onto detector after impinging on respective alignment patterns. The co-focused light is then used to determine proper alignment of the object for subsequent pattern features. This substantially increases accuracy of alignment of pattern features between layers, as compared to conventional systems.
26 Citations
20 Claims
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1. A system, comprising:
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an alignment system including first and second light sources and a detector that generates a measured signal therefrom; an object, including, a first layer including a first alignment pattern, and a second layer including a second alignment pattern, the second layer being below the first layer; and a focusing system that co-focuses on the detector light from the first and second light sources after each has impinged on the respective the first and second alignment patterns, whereby the object is aligned based on the measured signal and wherein the measured signal is generated from the co-focused light from the first and second alignment patterns. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. A method, comprising:
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(a) generating at least a first light beam and a second light beam; (b) impinging the first light beam onto a first alignment pattern on a first layer of an object; (c) focusing the impinged first light beam onto a detector; (d) impinging the second light beam onto a second alignment pattern on a second layer of the object, the second layer of the object being below the first layer of the object; (e) focusing the impinged second light beam onto the detector; (f) generating an alignment signal based on the detected first and second alignment patterns; and (g) aligning the object to receive a subsequent portion of a feature pattern based on step (f). - View Dependent Claims (14, 15, 16, 17, 18, 19)
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20. A system, comprising:
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means for generating at least a first light beam and a second light beam; means for impinging the first light beam onto a first alignment pattern on a first layer of an object; means for focusing the impinged first light beam onto a detector; means for impinging the second light beam onto a second alignment pattern on a second layer of the object, the second layer of the object being below the first layer of the object; means for focusing the impinged second light beam onto the detector; means for generating an alignment signal based on the detected first and second alignment patterns; and means for aligning the object to receive a subsequent portion of a feature pattern based on the alignment signal.
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Specification