US 9,754,895 B1Granted

Methods of forming semiconductor devices including determining misregistration between semiconductor levels and related apparatuses

AssigneeMicron Technology, Inc.

InventorsYang Chao, Joseph L. Hess, Keith E. Ypma, Kurt J. Bossart

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Abstract

A method of determining a lateral misregistration between levels of a semiconductor structure comprises imaging at least one first alignment mark in a first level of the structure and at least one second alignment mark in a second level of the structure. A digital image of the first and second alignment marks is formed, each of which are defined by a set of points having an x-value and a y-value. The x-values and y-values of points defining the first alignment mark and points defining the second alignment mark are averaged to determine a center of the first alignment mark and a center of the second alignment mark. An x-coordinate and a y-coordinate of the center of the first alignment mark is subtracted from the respective x-coordinate and y-coordinate of the center of the second alignment mark to determine a lateral misregistration between the first level and the second level. Related methods of forming a semiconductor wafer, semiconductor assembles and metrology tools for use in implementing the methods are disclosed.

Claims25

Dependent claims

A method of forming a semiconductor structure, the method comprising:

forming at least one first circular alignment mark at a known distance and orientation relative to electrically conductive elements on a first level of a structure;
forming at least one second circular alignment mark on a second level of the structure at a location corresponding to a same distance and orientation relative to the electrically conductive elements as the first circular alignment mark;
forming a digital image of the at least one first circular alignment mark on the first level of the structure and the at least one second circular alignment mark on the second level of the structure, wherein the at least one first circular mark is defined by a first set of points, each point of the first set of points comprising an x-coordinate and a y-coordinate and the at least one second circular alignment mark is defined by a second set of points, each point of the second set of points comprising an x-coordinate and a y-coordinate;
determining an x-coordinate and a y-coordinate of a center of the at least one first circular alignment mark by respectively averaging the x-coordinates of the first set of points and averaging the y-coordinates of the first set of points;
determining an x-coordinate and a y-coordinate of a center of the at least one second circular alignment mark by respectively averaging the x-coordinates of the second set of points and averaging the y-coordinates of the second set of points;
subtracting the x-coordinate and the y-coordinate of the center of the at least one first circular alignment mark from the respective x-coordinate and y-coordinate of the center of the at least one second circular alignment mark to determine a lateral misregistration between the first level and the second level;
and
responsive to determining the lateral misregistration, adjusting a location of the first level with respect to the second level by the determined lateral misregistration to position lateral edges of the first level to be substantially parallel with lateral edges of the second level.

5 more elements

A method of forming a semiconductor structure, the method comprising:

imaging at least one first alignment mark in a first level of a semiconductor structure and at least one second alignment mark in a second level of the semiconductor structure;
forming a digital image of the at least one first alignment mark and the at least one second alignment mark, wherein the at least one first alignment mark is defined by a first set of points, each point of the first set of points defined by an x-value and a y-value and the at least one second alignment mark is defined by a second set of points, each point of the second set of points defined by an x-value and a y-value;
averaging the x-values and the y-values of the first set of points to determine a respective x-value and a y-value of a center of the at least one first alignment mark;
averaging the x-values and the y-values of the second set of points to determine a respective x-value and a y-value of a center of the at least one second alignment mark;
subtracting the x-value and the y-value of the center of the at least one first alignment mark from the respective x-value and y-value of the center of the at least one second alignment mark to determine a magnitude and direction of misregistration between the first level and the second level of the semiconductor wafer;
and
moving a stage of a photolithography tool by an amount corresponding to the misregistration during formation of one or more electrically conductive elements of the semiconductor structure.

4 more elements

An apparatus, comprising:

a stage configured to carry a semiconductor wafer, the wafer comprising at least one first alignment mark located a known distance and orientation relative to electrically conductive elements on a first level of the wafer and at least one second alignment mark on a second level thereof and located at a location corresponding to a same distance and orientation relative to the electrically conductive elements as the at least one first alignment mark;
a camera configured to provide a digital image of the semiconductor wafer defining the at least one first alignment mark with a first set of points, each point of the first set of points defined by an x-value and a y-value and defining the at least one second alignment mark with a second set of points, each point of the second set of points defined by an x-value and a y-value;
and
a computing system operably coupled to the camera, the computing system configured to:
calculate an average of the x-values and the y-values of the first set of points to determine a respective x-value and a y-value of a center of the at least one first alignment mark;
calculate an average of the x-values and the y-values of the second set of points to determine a respective x-value and a y-value of a center of the at least one second alignment mark;
and
subtract the x-value and the y-value of the center of the at least one first alignment mark from the respective x-value and y-value of the center of the at least one second alignment mark to determine a magnitude and direction of misregistration between the first level and the second level of the semiconductor wafer;
wherein the stage is configured to move at least one of the first level and the second level with respect to the other of the first level and the second level to position lateral edges of the first level to be substantially parallel to lateral edges of the second level.

6 more elements

Dependencies are inferred from the claim text.