Multi-axis positioning device

An optical inspection system, comprising:

• A. an optical inspection tool including a light source, an optical objective, a detector assembly, an optical train which optically couples the light source, optical objective and detector and an inspection tool controller that is configured to process optical information received by the detector assembly;
• and
• B. a multi-axis positioning system, comprising:
• a translation stage configured to provide displacement in two dimensions between a base and an upper stage of the translation stage;
• a bottom plate rotatably coupled to the translation stage such that an axis of rotation of the bottom plate in a θ rotation direction is perpendicular to a plane defined by the two dimensions of displacement of the translation stage;
• at least one bottom plate motor operatively coupled between the bottom plate and the translation stage, the at least one bottom plate motor being configured to rotate the bottom plate assembly in the θ rotation direction relative to the translation stage;
• a top plate operatively coupled to the bottom plate with at least three Z axis motors disposed and operatively coupled between corresponding outer portions of the bottom plate and respective outer portions of the top plate and which are configured to generate displacement between the respective outer portions of the bottom plate and top plate in a Z axis direction substantially parallel to the axis of rotation of the bottom plate;
• a chuck secured to the top plate which is configured to releasably secure a specimen thereto and which is disposed in communication with an optical path of the optical objective of the optical inspection tool;
• at least three Z axis position sensors which are disposed and operatively coupled between the upper stage of the translation stage and the top plate and which are configured to measure relative displacement in the Z axis direction between the upper stage and the top plate;
• at least three θ position sensors which are operatively coupled between the upper stage of the translation stage and the top plate and which are configured to measure relative angular displacement in the θ rotation direction between the upper stage and the top plate;
• and
• a positioning system controller which is operatively coupled to the Z axis motors, the at least one bottom plate motor, the Z axis position sensors and the θ position sensors and which is configured to control actuation of the Z axis motors and at least one bottom plate motor.

A method of inspecting a specimen, comprising:

• loading the specimen into a chuck of a multi-axis positioning system, the multi-axis positioning system including a translation stage, a bottom plate rotatably coupled to the translation stage, a top plate operatively coupled to the bottom plate such that the top plate may be displaced relative to the bottom plate along a Z axis, a tip axis, a tilt axis and along a θ rotation direction, and the chuck being secured to the top plate;
• measuring a position of one or more test features disposed on the specimen to generate test feature position data, the test feature position data including a Z axis position of the one or more test features along an optical axis of an objective of an optical inspection tool;
• storing the test feature position data in a memory storage device;
• generating a look up chart of a surface orientation of the specimen from the test feature position data;
• and
• translating the specimen relative to the objective in an x-y plane perpendicular to the optical axis of the objective while positioning the specimen with the multi-axis positioning system according to the look up chart using theta position data feedback from a plurality of θ position sensors disposed and operatively coupled between the translation stage and top plate of the multi-axis positioning system and using Z axis position feedback from a plurality of Z axis position sensors disposed and operatively coupled between the translation stage and top plate of the multi-axis positioning system, the specimen being translated such that an upper surface of the specimen remains perpendicular to an optical axis of the objective and the upper surface of the specimen remains at a constant distance from the objective.

A method of inspecting a specimen, comprising:

• loading the specimen into a chuck of a multi-axis positioning system, the multi-axis positioning system including a translation stage, a bottom plate rotatably coupled to the translation stage, a top plate operatively coupled to the bottom plate such that the top plate may be displaced relative to the bottom plate along a Z axis, a tip axis, a tilt axis and along a θ rotation direction, and the chuck being secured to the top plate;
• translating the specimen relative to an optical inspection tool while positioning the specimen with the multi-axis positioning system using theta position data feedback from a plurality of θ position sensors disposed and operatively coupled between the translation stage and top plate of the multi-axis positioning system and using Z axis position feedback from a plurality of Z axis position sensors disposed and operatively coupled between the translation stage and top plate of the multi-axis positioning system, wherein translating the specimen comprises translating the specimen such that an upper surface of the specimen remains perpendicular to an optical axis of an objective of an optical inspection tool and the upper surface of the specimen remains at a constant distance from the objective along an optical axis of the objective;
• and
• transmitting Z axis position data of the specimen from an inspection tool controller of the inspection tool to a positioning system controller of the multi-axis positioning system.