Method and apparatus for overlay control using multiple targets

摘要

A method includes measuring a first overlay error between a first process layer and a second process layer using a first overlay target formed on the second process layer. A second overlay error between the first process layer and a third process layer is measured using a second overlay target formed on the third process layer. At least one parameter of an operating recipe for performing a photolithography process on the first process layer is determined based on the first and second overlay error measurements. A system includes a metrology tool and a controller. The metrology tool is configured to measure a first overlay error between a first process layer and a second process layer using a first overlay target formed on the second process layer and measure a second overlay error between the first process layer and a third process layer using a second overlay target formed on the third process layer. The controller is configured to determine at least one parameter of an operating recipe for performing a photolithography process on the first process layer based on the first and second overlay error measurements.