System and method for automated positioning of a substrate in a processing chamber

In an object processing apparatus having a central transfer chamber;

• a plurality of peripheral chambers positioned around the periphery of said central transfer chamber;
• a moveable object transfer means disposed in said transfer chamber and having an object support for loading, moving and unloading objects having a leading and a trailing edge to and from said peripheral chambers, which object support is moved within said central transfer chamber generally along an arcuate path between said peripheral chambers;
• the improvement which comprises:
• position control means for detecting the position of the object relative to said support and causing said transfer means to accurately position the object in one of said peripheral chambers, comprising:
• a) means for providing object support reference signals indicative of the position of an object support reference point;
• b) a sensor array including at least two sensors mounted along an axis generally transverse to the arcuate path, said sensors being triggered by the leading and trailing edges of the moving object as it passes therethrough and developing corresponding object position signals from which an object position reference point can be determined;
• and
• c) means responsive to the object support reference signals and the object position signals and operative to calculate the location of the object position relative to the object support, and further operative to move said object support to a corresponding offset position relative to said preselected location so as to position said object at said preselected location in one of the peripheral chambers.

In an object processing apparatus having a central transfer chamber;

• a plurality of peripheral chambers positioned around the periphery of said central transfer chamber;
• a moveable object transfer means disposed in said transfer chamber and having an object support for loading, moving and unloading objects having a leading and a trailing edge to and from said peripheral chambers, which object support is moved within said central transfer chamber generally along an arcuate path between said peripheral chambers;
• the improvement which comprises:
• position control means for detecting the position of the object relative to said support and causing said transfer means to accurately position the object in one of said peripheral chambers, comprising:
• a) means for providing object support reference signals indicative of the position of an object support reference point;
• b) a sensor array including at least two sensors mounted along an axis generally transverse to the arcuate path, said sensors being triggered by the leading and trailing edges of the moving object as it passes therethrough and developing corresponding object position signals from which an object position reference point can be determined;
• and
• c) means responsive to the object support reference signals and the object position signals and operative to calculate the location of the object position relative to the object support, and further operative to move said object support to a corresponding offset position relative to said preselected location so as to position said object at said preselected location in one of the peripheral chambers;
• wherein the means responsive to said object position signals and said object support signals includes a computer system programmed to control the transfer of said wafers from chamber to chamber, and wherein said computer system includes:
• control logic means operative to determine the wafer and object support reference points and to calculate the relative location of said wafer to said object support;
• means for controlling the movements of the object support' and
• means for interfacing the logic control means and the sensor array.

A method for accurately positioning an object having a centerpoint on a moveable object support, the position of the object support being known at all times, from a first location to a preselected second location, the position of said moveable object support at all times being known, and the position of said object relative to said moveable object support initially being unknown, comprising the steps of:

• rotating the object support about its axis from the first position to a second position past an array of sensors mounted generally transverse to the arcuate path;
• detecting perimeter points along the perimeter of the object as the moveable object support is moved along the arcuate path, thereby triggering the sensors to generate object signals from which the position of the centerpoint of said object can be determined relative to the known centerpoint position of said moveable object support;
• determining any position error between the centerpoints of the object support and the object;
• and
• moving said moveable object support and said object supported thereon so that said centerpoint of said object is coincident with said second selected location.

A method for determining the position of a moveable object support having a known width, a detectable centerpoint and a home reference position relative to a known location in a processing system, said moveable support being disposed within a transfer chamber having a plurality of chambers positioned around the periphery of said transfer chamber and moveable between said processing chambers along a generally arcuate path intersecting a radial axis, comprising the steps of:

• rotating said object support along said arcuate path past one or more sensors disposed at one or more points along said radial axis in said central transfer chamber thereby generating sensor signals;
• detecting the position of at least one of said sensors for generating sensor position signals;
• detecting the position of the moveable object support for generating object support position signals;
• and
• calculating the position of the object support relative to the known location from said sensor position signals and object support position signals.

A method for accurately positioning an object at a preselected location comprising:

• a) detecting the relative position of the object with respect to a moveable object support upon which said object is supported, said object support moveable along an arcuate path between a first location and said preselected location, the position of said moveable object support and said object relative to said moveable object support initially being unknown, comprising the steps of:
• b) rotating the object support about its axis from the first position to a second position along an arcuate path .past an array of at least two sensors mounted along an axis generally transverse to the arcuate path;
• c) detecting the position of a sensor for generating sensor signals;
• d) detecting the position of the moveable object support;
• e) calculating the relative position of the moveable object support with respect to the preselected location from said sensor signals and object support signals;
• f) detecting perimeter points along the perimeter of the object as the moveable object support is moved along the arcuate path, thereby triggering the sensors to generate object signals from which an object position point can be determined relative to said moveable object support,
• g) calculating the object position point relative to the position of the moveable object support from the object signals and the object support signals, and
• h) moving said moveable object support and said object supported thereon to the preselected location so that the object position point of said object is coincident with said preselected location.

In an object processing apparatus having a central transfer chamber and a plurality of peripheral chambers positioned about the periphery of said central transfer chamber;

• a moveable object transfer means disposed in said transfer chamber and having an object support for loading, moving and unloading objects having a leading and a trailing edge to and from said peripheral chambers, which object support is moved within said central transfer chamber generally along an arcuate path between said peripheral chambers;
• the improvement which comprises position control means for detecting the position of the object relative to said support and causing said transfer means to accurately position the object in one of said peripheral chambers, said position control means comprising:
• a) a prerecorded memory containing object support reference signals indicative of the position of a reference point on the object support;
• b) a sensor array including at least two sensors mounted along an axis generally transverse to said arcuate path, said sensors being triggered by the leading and trailing edges of the moving object as it passes therethrough and developing corresponding object position signals from which a reference point on the object can be determined;
• c) computer means responsive to the object support position signals and the object position signals operative to calculate the location of the reference point on the object support with respect to the location of the reference point on the object;
• d) motor means operative to move said object support to an offset position relative to said preselected location so as to position said object reference point at said preselected location in one of the peripheral chambers.