Patent ID: 7415180

Claim:
A method comprising: providing a bottom cladding layer on a substrate; providing a core layer over the bottom cladding layer; defining, by a single mask process, part of the core layer for an optical waveguide and part of the core layer for a template for a first pattern of marks, the first pattern of marks having a first frequency; providing a top cladding layer over the part of the core layer defining the optical waveguide; etching the core layer and the bottom cladding layer to form the first pattern of marks, defined by the template, in the bottom cladding layer; positioning a semiconductor chip that includes a second pattern of marks so that the second pattern of marks overlies the first pattern of marks, the second pattern of marks having a second frequency; directing light onto the first and second patterns; detecting a first optical signal, the first optical signal having a beat frequency based on a superposition of the first and second patterns of marks; and determining whether the semiconductor chip is properly positioned based on the detected optical signal.