Optical alignment method and apparatus

Claim 1

A method of aligning objects comprising: providing corresponding alignment patterns in at least two spaced regions on the objects, each of said patterns comprising at least one pair of non-parallel lines, scanning the images of said lines for each region in a straight line in a single direction, sensing the points where the scanning path intersects each line so as to produce signals indicative of the position of said objects with respect to one another, such that the Y coordinate position of the intersection point of each pair of lines is determinable from the average of the times from an arbitrary starting time at which the scanning path intersects each line of said pair and where the X coordinate position of the intersection point of each pair of lines is determinable from the average of the difference of the times from said starting time at which the scanning path intersects each line of said pair, and changing the position of said objects in response to said signals.

Claim 2

A method of aligning objects comprising: providing corresponding alignment patterns in at least two spaced regions on the objects, each of said patterns comprising at least one pair of non-parallel lines, scanning the images of said lines for each region in a straight line in a single direction, sensing the points where the scanning path intersects each line so as to produce signals indicative of the position of said objects with respect to one another, such that the Y coordinate position of the intersection point of each pair of lines is determinable from the average of the times from an arbitrary starting time at which the scanning path intersects each line of said pair and where the X coordinate position of the intersection point of each pair of lines is determinable from the average of the difference of the times from said starting time at which the scanning path intersects each line of said pair, and changing the position of said objects in response to said signals.

Claim 3

A system for aligning objects comprising: corresponding alignment patterns in at least two spaced regions on the objects, each of said patterns comprising at least one pair of non-parallel lines, means for scanning the images of said lines for each region in a straight line in a single direction, means for sensing the points where the scanning path intersects each line so as to produce signals indicative of the position of said objects with respect to one another, such that the Y coordinate position of the intersection point of each pair of lines is determinable from the average of the times from an arbitrary starting time at which the scanning path intersects each line of said pair and where the X coordinate position of the intersection point of each pair of lines is determinable from the average of the difference of the times from said starting time at which the scanning path intersects each line of said pair, and means to change the position of said objects in response to said signals.

Claim 4

A system for aligning objects comprising: corresponding alignment patterns in at least two spaced regions on the objects, each of said patterns comprising at least one pair of non-parallel lines, means for scanning the images of said lines for each region in a straight line in a single direction, means for sensing the points where the scanning path intersects each line so as to produce signals indicative of the position of said objects with respect to one another, such that the Y coordinate position of the intersection point of each pair of lines is determinable from the average of the times from an arbitrary starting time at which the scanning path intersects each line of said pair and where the X coordinate position of the intersection point of each pair of lines is determinable from the average of the difference of the times from said starting time at which the scanning path intersects each line of said pair, and means to change the position of said objects in response to said signals.

Claim 5

A method of aligning objects comprising: providing corresponding alignment patterns in at least two spaced regions on the objects, each of said patterns comprising at least one pair of non-parallel lines, placing and holding said objects in approximate alignment, forming diffraction patterns of said regions, spatially filtering said diffraction patterns, scanning the filtered images of said lines from each region in a single direction and sensing the points where the scanning path intersects each line so as to produce signals indicative of the X, Y cartesian coordinate position of said objects with respect to one another and changing the position of saId objects in response to said signals until said objects are aligned.

Claim 6

A method of aligning objects comprising: providing corresponding alignment patterns in at least two spaced regions on the objects, each of said patterns comprising at least one pair of non-parallel lines, placing and holding said objects in approximate alignment, forming diffraction patterns of said regions, spatially filtering said diffraction patterns, scanning the filtered images of said lines from each region in a single direction and sensing the points where the scanning path intersects each line so as to produce signals indicative of the X, Y cartesian coordinate position of said objects with respect to one another and changing the position of saId objects in response to said signals until said objects are aligned.

Claim 7

A system for aligning objects comprising: corresponding alignment patterns in at least two spaced regions on the objects, each of said patterns comprising at least one pair of non-parallel lines, means for placing and holding said objects in approximate alignment, means for forming diffraction patterns of said regions, means for spatially filtering said diffraction patterns, means for scanning the filtered images of said lines from each region in a single direction and means for sensing the points where the scanning path intersects each line so as to produce signals indicative of the X, Y cartesian coordinate position of said objects with respect to one another, and means for changing the position of said objects in response to said signals until said objects are aligned.

Claim 8

A system for aligning objects comprising: corresponding alignment patterns in at least two spaced regions on the objects, each of said patterns comprising at least one pair of non-parallel lines, means for placing and holding said objects in approximate alignment, means for forming diffraction patterns of said regions, means for spatially filtering said diffraction patterns, means for scanning the filtered images of said lines from each region in a single direction and means for sensing the points where the scanning path intersects each line so as to produce signals indicative of the X, Y cartesian coordinate position of said objects with respect to one another, and means for changing the position of said objects in response to said signals until said objects are aligned.

Claim 9

A system for finely aligning a workpiece with a mask comprising: at least two corresponding spaced apart regions on said workpiece and said mask having alignment patterns each of which patterns comprising at least one pair of non-parallel lines, a light source means for directing collimated light to said regions, a pair of compound microscopes for forming magnified images of said regions, a pair of bandpass filters located at the frequency plane of the objective lenses of said microscopes to remove the light frequencies not associated with said alignment patterns, means for scanning the filtered magnified images of said lines of said alignment patterns from each region in a single direction past sensing means which generate signals characteristic of the point where the scanning path intersects each line so as to produce signals indicative of the position of said workpiece and said mask, means for placing and holding said workpiece and mask in approximate alignment said means including indexing means for changing the relative position of said workpiece and said mask and, control means to receive said signals and compute the relative position of said workpiece and said mask from said signals and cause said indexing means to change the relative position of said mask and workpiece until said received signals indicate that said mask and workpiece are finely aligned.

Claim 10

A system for finely aligning a workpiece with a mask comprising: at least two corresponding spaced apart regions on said workpiece and said mask having alignment patterns each of which patterns comprising at least one pair of non-parallel lines, a light source means for directing collimated light to said regions, a pair of compound microscopes for forming magnified images of said regions, a pair of bandpass filters located at the frequency plane of the objective lenses of said microscopes to remove the light frequencies not associated with said alignment patterns, means for scanning the filtered magnified images of said lines of said alignment patterns from each region in a single direction past sensing means which generate signals characteristic of the point where the scanning path intersects each line so as to produce signals indicative of the position of said workpiece and said mask, means for placing and holding said workpiece and mask in approximate alignment said means including indexing means for changing the relative position of said workpiece and said mask and, control means to receive said signals and compute the relative position of said workpiece and said mask from said signals and cause said indexing means to change the relative position of said mask and workpiece until said received signals indicate that said mask and workpiece are finely aligned.

Claim 12

A system for finely aligning a workpiece with respect to a photomask comprising: at least two corresponding spaced apart regions on said workpiece and said photomask having alignment patterns each of which pattern comprising at least one pair of non-parallel lines, a source of collimated light, means for directing said light to said regions, a first pair of lenses for forming Fraunhofer diffraction patterns of each region, a pair of band pass filters located at the frequency plane of said lenses to remove noise and pass substantially only the spatial frequencies of the alignment patterns, a second pair of lenses for magnifying the filtered images of the alignment pattern and imaging said patterns on a pair of mirrors which are mounted for rotation, means to rotate said mirrors at constant speed to scan said images in a single direction past sensing means to produce signals indicative of the time of each line crossing from an arbitrary time zero for each pattern, means to position and hold said workpiece and photomask in approximate optical alignment and means including indexing means for changing the relative orientation of said mask and said workpiece with respect to one another and control means for computing the relative position of said mask and said workpiece from said signals and for causing said indexing means to change the position of said mask and said workpiece until said signals indicate that said mask and said workpiece are optically aligned.

Claim 13

A system for finely aligning a workpiece with respect to a photomask comprising: at least two corresponding spaced apart regions on said workpiece and said photomask having alignment patterns each of which pattern comprising at least one pair of non-parallel lines, a source of collimated light, means for directing said light to said regions, a first pair of lenses for forming Fraunhofer diffraction patterns of each region, a pair of band pass filters located at the frequency plane of said lenses to remove noise and pass substantially only the spatial frequencies of the alignment patterns, a second pair of lenses for magnifying the filtered images of the alignment pattern and imaging said patterns on a pair of mirrors which are mounted for rotation, means to rotate said mirrors at constant speed to scan said images in a single direction past sensing means to produce signals indicative of the time of each line crossing from an arbitrary time zero for each pattern, means to position and hold said workpiece and photomask in approximate optical alignment and means including indexing means for changing the relative orientation of said mask and said workpiece with respect to one another and control means for computing the relative position of said mask and said workpiece from said signals and for causing said indexing means to change the position of said mask and said workpiece until said signals indicate that said mask and said workpiece are optically aligned.