METHOD AND APPARATUS FOR OVERLAY CONTROL USING MULTIPLE TARGETS

摘要

A method includes measuring a first overlay error between a first process layer (360) and a second process layer (340) using a first overlay target (330) formed on the second process layer (340). A second overlay error between the first process layer (360) and a third process layer (320) is measured using a second overlay target (310) formed on the third process layer (360). At least one parameter of an operating recipe for performing a photolithography process on the first process layer (360) is determined based on the first and second overlay error measurements. A system (200) includes a metrology tool (230) and a controller (240). The metrology tool (230) is configured to measure a first overlay error between a first process layer (360) and a second process layer (340) using a first overlay target (330) formed on the second process layer (340) and measure a second overlay error between the first process layer (360) and a third process layer (320) using a second overlay target (310) formed on the third process layer (360). The controller (240) is configured to determine at least one parameter of an operating recipe for performing a photolithography process on the first process layer (360) based on the first and second overlay error measurements.