Patent ID: 7368208

Claim:
A semiconductor production method, comprising: providing a production reticle, the production reticle having a pattern that includes one or more circuit features, phase shift target structures and overlay target structures; transferring the circuit features, phase shift target structures and overlay target structures multiple times across a test wafer surface for various levels of focus so as to form a focus matrix, wherein the transferring of the phase shift target structures is accomplished with the production reticle without using other reticles; measuring the pattern shift of the phase shift target structures transferred to the test wafer at their various locations using an overlay metrology tool; calculating the phase difference of the production reticle based on the pattern shift and the level of focus of the phase shift target structures, wherein the phase difference corresponds to a difference in an optical phase of different transmissive portions of the production reticle that are adjacent to the phase shift target structures of the production reticle; qualifying the phase difference of the production reticle; transferring the circuit features, phase shift target structures and overlay target structures onto a production wafer when the phase difference of the production reticle meets desired limits based on qualifying the phase difference of the production reticle; measuring the pattern shift of the overlay target structures transferred to the production wafer using an overlay metrology tool; and calculating the pattern placement error of the overlay target structures.