Semiconductor wafer position shift measurement and correction
AssigneeASM America, Inc.
InventorIvo Raaijmakers
Life of this patent
Estimating the term…
Abstract
A method and apparatus is provided for determining substrate drift from its nominal or intended position. The apparatus includes at least two fixed reference points. The reference points can be fixed with respect to the processing tool, or with respect to the end effector. As a robotic arm moves the end effector and substrate along a path, a camera captures images of the edge of the substrate and the reference points. Two or more cameras can also be provided. A computer can then calculate positional drift of the substrate, relative to its expected or centered position on the end effector, based upon these readings, and this drift can be corrected in subsequent robotic arm movement.
Claims24
A method of accurately positioning a substrate within a semiconductor processing apparatus, the method comprising:
- loading the substrate onto an end effector coupled to a robot;
- moving the substrate and end effector along a path with the robot;
- capturing a first image of a first edge portion of the substrate along with a proximately located first reference point;
- capturing a second image of a second edge portion of the substrate along with a proximately located second reference point;
- determining a difference in position of the substrate relative to an ideal substrate position by using the captured images;
- and
- compensating for any difference in position during subsequent robot movement of the substrate.
A method of accurately positioning a substrate within a semiconductor processing apparatus, the method comprising:
- moving a substrate along a path with the robot;
- capturing a first image of a first portion of an edge of the substrate and a first reference mark;
- capturing a second image of a second portion of the edge of the substrate and a second reference mark;
- measuring a distance from the respective reference mark to the edge of the substrate for each of the first and second images;
- and
- calculating a positional drift of the substrate with respect to an ideally positioned substrate using the measured distances.
A system for calculating substrate drift upon an end effector, comprising:
- a robot supporting and moving the end effector, the robot configured to move the end effector and a supported substrate along a translational path including a first position and a second position;
- a reference mark;
- a camera fixed with respect to the reference mark, the camera positioned to capture a first image with the substrate in the first position and a second image with the substrate in a second position, each of the first and second images including a reference mark that is fixed with respect to the camera and a different portions of an edge of the substrate;
- and
- a processor configured to calculate a position of the substrate relative to the reference mark, the processor receiving input form the camera and the robot.
Dependencies are inferred from the claim text.