Method and apparatus for article positioning utilizing an incremental article drive system and null transit counter

Claim 3

incrementally moving said article in response to said electrical signal in a first direction parallel to said axis whenever said signal parameter is in a first state and in the opposite direction whenever the signal parameter is in the second state;

Claim 4

incrementally moving said article in response to said electrical signal in a first direction parallel to said axis whenever said signal parameter is in a first state and in the opposite direction whenever the signal parameter is in the second state;

Claim 7

incrementally moving said article in response to said X, Y, and theta electrical signals in first directions parallel to said first axis, perpendicular to said first axis and around the intersection of said axes, respectively, when the respective signals are in the first state and in the opposite directions when the respective signals are in the second state;

Claim 8

incrementally moving said article in response to said X, Y, and theta electrical signals in first directions parallel to said first axis, perpendicular to said first axis and around the intersection of said axes, respectively, when the respective signals are in the first state and in the opposite directions when the respective signals are in the second state;

Claim 9

counting the changes in state of said X, Y and theta signals; and,

Claim 10

counting the changes in state of said X, Y and theta signals; and,

Claim 11

counting the changes in state of said parameter; and,

Claim 12

counting the changes in state of said parameter; and,

Claim 15

The article positioning system of claim 3 wherein said article positioning means includes means for producing linear motion of the article in said first and second directions.

Claim 16

terminating the incremental movement of said article when the signal has made a preselected number of changes in state.

Claim 17

terminating the incremental movement of said article when the signal has made a preselected number of changes in state.

Claim 18

terminating the incremental movement of said article when each of the X, Y, and theta signals have made a preselected number of changes in state.

Claim 19

terminating the incremental movement of said article when each of the X, Y, and theta signals have made a preselected number of changes in state.

Claim 20

The article positioning system of claim 3 wherein said article positioning means includes means for producing rotary motion of the article in said first and second directions.

Claim 23

The system of claim 6 further characterized by said inhibiting means being operable only after all of said counting means have reached their respective preselected counts.

Claim 24

In an electro-optical mask-to-wafer systEm for aligning a wafer in a preselected translational and rotary orientation with respect to first and second mask coordinate axes, the wafer having at least two target areas which have a light reflecting characteristic contrasting with that of the wafer, the combination of: a mask having a plurality of apertures which expose predetermined portions of said target areas when the mask is aligned in superposed relation to said wafer; means for illuminating said target areas through said mask apertures; means responsive to the light reflected through a first set of at least two of said mask apertures for producing an X electrical signal having a parameter which changes between a first state and a second state depending upon the direction of displacement of the wafer with respect to the first coordinate axis of the mask; means responsive to the light reflected through a second set of at least two of said mask apertures for producing a Y electrical signal having a parameter which changes between a first state and a second state depending upon the direction of displacement of the wafer with respect to the second coordinate axis of the mask; means for producing a theta electrical signal having a parameter which changes between a first state and a second state depending upon the direction of the rotational displacement of the wafer with respect to the preselected orientation; an X positioning means responsive to said X electrical signal for incrementally translating said wafer parallel to the first coordinate mask axis in a first direction whenever the signal parameter is in the first state and in a second and opposite direction whenever the signal parameter is in the second state; an X counting means coupled to said X electrical signal producing means for counting the changes in state of said X signal parameter; a Y positioning means responsive to said Y electrical signal for incrementally translating said wafer perpendicular to the first coordinate mask axis in a first direction whenever the signal parameter is in the first state and in a second and opposite direction whenever the signal parameter is in the second state: a Y counting means coupled to said Y electrical signal producing means for counting the changes in state of said Y signal parameter; a theta positioning means responsive to said theta electrical signal for incrementally rotating said wafer around the intersection of the first and second coordinate mask axes in a first direction whenever the signal parameter is in the first state and in a second and opposite direction whenever the signal parameter is in the second state; a theta counting means coupled to said theta electrical signal producing means for counting the changes in state of said theta signal parameters; and, means responsive to preselected counts in said X, Y and theta counting means for inhibiting said X, Y and theta article positioning means.

Claim 25

In an electro-optical mask-to-wafer systEm for aligning a wafer in a preselected translational and rotary orientation with respect to first and second mask coordinate axes, the wafer having at least two target areas which have a light reflecting characteristic contrasting with that of the wafer, the combination of: a mask having a plurality of apertures which expose predetermined portions of said target areas when the mask is aligned in superposed relation to said wafer; means for illuminating said target areas through said mask apertures; means responsive to the light reflected through a first set of at least two of said mask apertures for producing an X electrical signal having a parameter which changes between a first state and a second state depending upon the direction of displacement of the wafer with respect to the first coordinate axis of the mask; means responsive to the light reflected through a second set of at least two of said mask apertures for producing a Y electrical signal having a parameter which changes between a first state and a second state depending upon the direction of displacement of the wafer with respect to the second coordinate axis of the mask; means for producing a theta electrical signal having a parameter which changes between a first state and a second state depending upon the direction of the rotational displacement of the wafer with respect to the preselected orientation; an X positioning means responsive to said X electrical signal for incrementally translating said wafer parallel to the first coordinate mask axis in a first direction whenever the signal parameter is in the first state and in a second and opposite direction whenever the signal parameter is in the second state; an X counting means coupled to said X electrical signal producing means for counting the changes in state of said X signal parameter; a Y positioning means responsive to said Y electrical signal for incrementally translating said wafer perpendicular to the first coordinate mask axis in a first direction whenever the signal parameter is in the first state and in a second and opposite direction whenever the signal parameter is in the second state: a Y counting means coupled to said Y electrical signal producing means for counting the changes in state of said Y signal parameter; a theta positioning means responsive to said theta electrical signal for incrementally rotating said wafer around the intersection of the first and second coordinate mask axes in a first direction whenever the signal parameter is in the first state and in a second and opposite direction whenever the signal parameter is in the second state; a theta counting means coupled to said theta electrical signal producing means for counting the changes in state of said theta signal parameters; and, means responsive to preselected counts in said X, Y and theta counting means for inhibiting said X, Y and theta article positioning means.

Claim 26

The system of claim 8 further characterized by said inhibiting means being operable only after all of said counting means have reached their respective preselected counts.

Claim 27

In an electro-optical mask-to-wafer system for aligning a wafer in a preselected translational and rotary orientation with respect to first and second mask coordinate axes, the wafer having at least two target areas which have a light reflecting characteristic contrasting with that of the wafer, the combination of: a mask having a plurality of apertures which expose predetermined portions of said target areas when the mask is aligned in superposed relation to said wafer, said target area portions and superposed mask apertures defining first and second target alignment stations; means for illuminating said target area portions through said mask apertures; means responsive to the light reflected through a first set of at least two Of said mask apertures at said first alignment station for producing an X error electrical signal having a parameter which changes between a first state and second state depending on the direction of displacement of the wafer with respect to the first coordinate axis of the mask; means responsive to the light reflected through a second set of at least two of said mask apertures at said first alignment station for producing a Y1 electrical signal having a parameter which changes between a first state and a second state depending on the direction of displacement of the wafer with respect to the second coordinate axis of the mask; means responsive to the light reflected through a first set of at least two of said mask apertures at said second alignment station for producing a Y2 electrical signal having a parameter which changes between a first state and a second state depending upon the direction of displacement of the wafer with respect to the second coordinate axis of the mask; means for producing a theta error electrical signal having a parameter which changes between a first state and a second state depending upon the direction of the rotational displacement of the wafer with respect to the preselected orientation, said theta error signal being produced only when the Y1 and Y2 signal parameter states are not the same; means for producing a Y error electrical signal having a parameter which changes between a first state and a second state depending upon the direction of displacement of the wafer with respect to the second coordinate axis of the mask, said Y error signal being produced only when the Y1 and Y2 signals are in the same state: an X positioning means responsive to said X error electrical signal for translating said wafer parallel to the first coordinate mask axis in a first direction whenever the signal parameter is in the first state and a second and opposite direction whenever the signal parameter is in the second state; a Y position means responsive to said Y error electrical signal for translating said wafer perpendicular to the first coordinate mask axis in a first direction whenever the signal parameter is in the first state and in a second and opposite direction whenever the signal parameter is in the second state; and, a theta positioning means responsive to said theta error electrical signal for rotating said wafer around the intersection of the first and second coordinate mask axis in a first direction whenever the signal parameter is in the first state and in a second and opposite direction whenever the signal parameter is in the second state.

Claim 28

In an electro-optical mask-to-wafer system for aligning a wafer in a preselected translational and rotary orientation with respect to first and second mask coordinate axes, the wafer having at least two target areas which have a light reflecting characteristic contrasting with that of the wafer, the combination of: a mask having a plurality of apertures which expose predetermined portions of said target areas when the mask is aligned in superposed relation to said wafer, said target area portions and superposed mask apertures defining first and second target alignment stations; means for illuminating said target area portions through said mask apertures; means responsive to the light reflected through a first set of at least two Of said mask apertures at said first alignment station for producing an X error electrical signal having a parameter which changes between a first state and second state depending on the direction of displacement of the wafer with respect to the first coordinate axis of the mask; means responsive to the light reflected through a second set of at least two of said mask apertures at said first alignment station for producing a Y1 electrical signal having a parameter which changes between a first state and a second state depending on the direction of displacement of the wafer with respect to the second coordinate axis of the mask; means responsive to the light reflected through a first set of at least two of said mask apertures at said second alignment station for producing a Y2 electrical signal having a parameter which changes between a first state and a second state depending upon the direction of displacement of the wafer with respect to the second coordinate axis of the mask; means for producing a theta error electrical signal having a parameter which changes between a first state and a second state depending upon the direction of the rotational displacement of the wafer with respect to the preselected orientation, said theta error signal being produced only when the Y1 and Y2 signal parameter states are not the same; means for producing a Y error electrical signal having a parameter which changes between a first state and a second state depending upon the direction of displacement of the wafer with respect to the second coordinate axis of the mask, said Y error signal being produced only when the Y1 and Y2 signals are in the same state: an X positioning means responsive to said X error electrical signal for translating said wafer parallel to the first coordinate mask axis in a first direction whenever the signal parameter is in the first state and a second and opposite direction whenever the signal parameter is in the second state; a Y position means responsive to said Y error electrical signal for translating said wafer perpendicular to the first coordinate mask axis in a first direction whenever the signal parameter is in the first state and in a second and opposite direction whenever the signal parameter is in the second state; and, a theta positioning means responsive to said theta error electrical signal for rotating said wafer around the intersection of the first and second coordinate mask axis in a first direction whenever the signal parameter is in the first state and in a second and opposite direction whenever the signal parameter is in the second state.