Method and apparatus to correct water drift
AssigneeASM America, Inc.
InventorZhimin Lu
Life of this patent
Estimating the term…
Abstract
A method and apparatus is provided for determining workpiece drift from its nominal or intended position. The apparatus includes two proportionate sensors, each of which gives an output reading that depends upon how much of the sensor beam is blocked by an edge of the workpiece. A computer can calculate positional drift based upon these readings. Also disclosed is a method for aligning proportionate sensors to be parallel to one another.
Claims45
A method of accurately positioning a substrate within a semiconductor processing apparatus, the method comprising:
- loading a reference substrate onto a robot;
- moving the robot with the reference substrate to a nominal robot position at a positioning station;
- recording reference substrate data from a sensor at the positioning station while the robot is at the nominal robot position;
- loading a process substrate onto the robot;
- moving the robot with the process substrate to the nominal robot position at the positioning station;
- recording process substrate data from the sensor at the positioning relating to the process substrate at the positioning station;
- calculating a substrate drift of the process substrate relative to the reference substrate;
- and
- compensating for the substrate drift in subsequent robot movement of the process substrate.
A system for accurately positioning a workpiece during movement thereof, the system comprising:
- a positioning station comprising at least two proportionate sensors aligned parallel to one another, each sensor producing an output inversely proportional to a sensor beam area blocked by the workpiece;
- and
- a computer instructing a robot to move the workpiece into a position at the positioning station wherein at least two of the sensors have their sensor beams partially blocked by an edge of the workpiece, the computer programmed to
- read outputs from the sensors,
- calculate a positional drift relative to an expected workpiece position, and
- adjust a robot position to compensate for the positional drift.
A method of orienting at least one sensor for determining a position of a substrate, comprising:
- placing a sensor within a processing system in an initial orientation;
- moving the substrate to a plurality of substrate positions;
- collecting data from the sensor at the plurality of substrate positions;
- and
- adjusting the sensor from the initial orientation based upon the data collected by the sensor.
A method of orienting a sensor beam to have a longitudinal direction of the beam parallel to a translation direction of a substrate positioning device, the method comprising:
- (a) determining a general translation direction of a robot end effector, to which the substrate is attached for transport;
- (b) installing a sensor system comprising a transmitter, which produces the sensor beam with a cross-section length and thickness, wherein the length is substantially larger than the thickness and having a direction along the length that is defined as a longitudinal direction, and a receiver which measures a maximum analog voltage, νmax, when a full intensity of the sensor beam reaches the receiver and also measures a linearly decreasing voltage as the sensor beam is increasingly blocked by the substrate and smaller portions of the sensor beam reach the receiver;
- (c) placing the substrate onto the end effector,
- (d) moving the substrate to a centering station at a position pi where the sensor beam is blocked, in part, by a leading edge of the substrate, and the receiver indicates a voltage, ν1−,
- (e) moving the substrate to a position pi′ along the translation direction where the sensor beam is blocked, in part, by a trailing edge of the substrate and the receiver indicates a voltage of νi′, such that νi′=νmax−νi;
- (f) repeating steps (d) and (c) for at least i={1, 2};
- (g) calculating a value ƒi for all i, where ƒi is a function of a distance moved between positions pi and pi′;
- and
- (h) rotating the sensor system ƒi is not constant within a predetermined tolerance for all i and repeating steps (d)-(h).
Dependencies are inferred from the claim text.