Evaluating a geometric or material property of a multilayered structure
First Claim
1. A method for evaluating a structure, the method comprising:
- illuminating a region of the structure with a beam, the structure having a plurality of lines passing through said region;
generating an electrical signal indicative of an attribute of a portion of the beam, the portion being reflected from said region;
repeating the acts of “
illuminating” and
“
generating”
in another region of the structure having another plurality of lines, thereby to obtain another electrical signal; and
comparing said electrical signal with said another electrical signal to identify variation of a property in said region relative to said another region.
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Accused Products
Abstract
A structure having a number of traces passing through a region is evaluated by using a beam of electromagnetic radiation to illuminate the region, and generating an electrical signal that indicates an attribute of a portion (also called “reflected portion”) of the beam reflected from the region. The just-described acts of “illuminating” and “generating” are repeated in another region, followed by a comparison of the generated signals to identify variation of a property between the two regions. Such measurements can identify variations in material properties (or dimensions) between different regions in a single semiconductor wafer of the type used in fabrication of integrated circuit dice, or even between multiple such wafers. In one embodiment, the traces are each substantially parallel to and adjacent to the other, and the beam has wavelength greater than or equal to a pitch between at least two of the traces. In one implementation the beam is polarized, and can be used in several ways, including, e.g., orienting the beam so that the beam is polarized in a direction parallel to, perpendicular to, or at 45° to the traces. Energy polarized parallel to the traces is reflected by the traces, whereas energy polarized perpendicular to the traces passes between the traces and is reflected from underneath the traces. Measurements of the reflected light provide an indication of changes in properties of a wafer during a fabrication process.
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Citations
39 Claims
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1. A method for evaluating a structure, the method comprising:
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illuminating a region of the structure with a beam, the structure having a plurality of lines passing through said region; generating an electrical signal indicative of an attribute of a portion of the beam, the portion being reflected from said region; repeating the acts of “
illuminating” and
“
generating”
in another region of the structure having another plurality of lines, thereby to obtain another electrical signal; andcomparing said electrical signal with said another electrical signal to identify variation of a property in said region relative to said another region. - View Dependent Claims (2, 3)
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4. A method for evaluating a structure, the method comprising:
- illuminating a region of the structure with a beam, the structure having a plurality of lines passing through said region;
generating an electrical signal indicative of an attribute of a portion of the beam, the portion being reflected from said region; repeating the acts of “
illuminating” and
“
generating”
in another region having another plurality of lines, thereby to obtain another electrical signal; andcomparing said electrical signal with said another electrical signal to identify variation of a property between said region and said another region; wherein the attribute being measured is color. - View Dependent Claims (5, 6)
- illuminating a region of the structure with a beam, the structure having a plurality of lines passing through said region;
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7. A method for evaluating a structure having at least a plurality of lines and a layer in contact with said lines, the method comprising:
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illuminating a region of the structure using a beam of electromagnetic radiation, the structure having a plurality of lines in said region, the beam having a wavelength greater than or equal to a pitch between at least two lines in the plurality, said two lines being each at least substantially parallel to and adjacent to the other;
endgenerating an electrical signal indicative of color of a portion of the beam, the portion being reflected from said region. - View Dependent Claims (8, 9, 10, 11, 12)
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13. A method for evaluating a structure having at least a plurality of lines and a layer in contact with said lines, at least two lines in the plurality being each at least substantially parallel to the other, the method comprising:
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illuminating the structure with a beam of electromagnetic radiation having at least two polarized components wherein a first component is substantially parallel to the two lines, and a second component is substantially perpendicular to the two lines; generating a first electrical signal indicative of color of a portion of the first component reflected by at least said two lines; and generating a second electrical signal indicative of color of a portion of the second component reflected by the layer; wherein the acts of generating are performed at least contemporaneously relative to one another. - View Dependent Claims (14)
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15. A method for evaluating a structure having at least a plurality of lines and a layer in contact with said lines, at least two lines in the plurality being each at least substantially parallel to the other, the method comprising:
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illuminating a first region of the structure with a first beam of electromagnetic radiation; illuminating a second region of the structure with a second beam of electromagnetic radiation; generating a first electrical signal indicative of color of a portion of the first beam reflected from the first region; generating a second electrical signal indicative of color of a portion of the second beam reflected from the second region; and using a difference between the first electrical signal wit the second electrical signal as a profile of a surface in the structure. - View Dependent Claims (16, 17, 18)
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19. An apparatus for evaluating a wafer having a plurality of lines, said apparatus comprising:
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a source of a beam of electromagnetic radiation having a wavelength greater than or equal to a pitch between at least two lines in said wafer, said two lines being each at least substantially parallel to and adjacent to the other; a camera that measures color located in a path of a portion of the bean, the portion being reflected from said region; a memory; and a comparator coupled to each of said memory and said camera. - View Dependent Claims (20, 21, 22, 23)
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24. An apparatus for evaluating a wafer having a plurality of lines, said apparatus comprising:
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a source of abeam of electromagnetic radiation having a wavelength greater than or equal to a pitch between at least twa lines in said wafer, said two lines being each at least substantially parallel to and adjacent to the other; a polarizing beam splitter located in a path of said beam between said source and said wafer; and a polarizer located in a path of said beam between the polarizing beam splitter and the wafer. - View Dependent Claims (25)
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26. A method for evaluating a structure having at least a plurality of lines and a layer in contact with said lines, at least two lines in the plurality being each at least substantially parallel to the other, the method comprising:
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polarizing a beam of white light to obtain a beam of polarized white light; illuminating a region of the structure with said beam of polarized white light; and measuring a color of a portion of said beam of polarized white light reflected from the region. - View Dependent Claims (27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39)
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Specification