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

Patent metadata

Field	Value
Publication number	US-9754895-B1
Application number	US-201615062452-A
Country	US
Kind code	B1
Filing date	Mar 7, 2016
Priority date	Mar 7, 2016
Publication date	Sep 5, 2017
Grant date	Sep 5, 2017

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.

First claim

What is claimed is:

1. 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.

2. The method of claim 1 , further comprising forming the at least one second circular alignment mark to have a smaller diameter than a diameter of the at least one first circular alignment mark.

3. The method of claim 2 , further comprising forming the at least one second circular alignment mark to be substantially disposed within edges of the at least one first circular alignment mark.

4. The method of claim 1 , further comprising:
forming the at least one first circular alignment mark to comprise a diameter between about 10 μm and about 30 μm; and
forming the at least one second circular alignment mark to comprise a diameter between about 5 μm and about 20 μm.

5. The method of claim 1 , further comprising forming at least one of the at least one first circular alignment mark or the at least one second circular alignment mark over a through substrate via.

6. The method of claim 1 , wherein 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 comprises:
subtracting the x-coordinate of the center of the at least one first alignment mark from the x-coordinate of the center of the at least one second alignment mark to determine a lateral misregistration in an x-direction; and
subtracting the y-coordinate of the center of the at least one first alignment mark from the y-coordinate of the center of the at least one second alignment mark to determine a lateral misregistration in a y-direction.

7. The method of claim 6 , wherein the structure comprises a semiconductor wafer and adjusting a location of the first level with respect to the second level by the determined lateral misregistration comprises:
moving a wafer stage supporting the semiconductor wafer laterally in the x-direction by a magnitude corresponding to the misregistration in the x-direction; and
moving the wafer stage laterally in the y-direction by a magnitude corresponding to the misregistration in the y-direction.

8. The method of claim 1 , wherein forming a digital image of at least one first circular alignment mark comprises defining the at least one first circular alignment mark with at least 3 points.

9. The method of claim 1 , further comprising selecting each point of the first set of points to be separated from an adjacent point of the first set of points by about a same distance.

10. The method of claim 1 , wherein:
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 comprises forming the at least one second circular alignment mark on a photoresist material; and
adjusting a location of the first level with respect to the second level by the determined lateral misregistration comprises moving the structure by the determined lateral misregistration prior to exposing the photoresist material.

11. The method of claim 1 , wherein 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 comprises forming the at least one first circular alignment mark on active regions of the structure.

12. 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.

13. The method of claim 12 , further comprising defining the at least one first alignment mark with a first set of points comprising at least a plurality of points.

14. The method of claim 12 , wherein averaging the x-values and the y-values of the first set of points comprises averaging the x-values and the y-values of a plurality of points that define a circle, each of the points separated from a circumferentially adjacent point by about a same distance.

15. The method of claim 12 , further comprising selecting the at least one first alignment mark and the at least one second al

Assignees

• Micron Technology Inc

Inventors

• Chao Yang
• Hess Joseph L
• Ypma Keith E
• Bossart Kurt J

Classifications

• H10W90/724

  between a chip and a stacked insulating package substrate, interposer or RDL · CPC title

• H10W72/823

  Interconnections through encapsulations, e.g. pillars through molded resin on a lateral side a chip · CPC title

• H10W90/722

  between stacked chips · CPC title

• H10W90/00

  Package configurations · CPC title

• H10W46/301

  for alignment · CPC title