Patent ID: 6628391
Filing Date: 2003-09-30
Classification: G02B,G03F

Abstract:
A method of aligning a mask having a plurality of first detection marks, said mask being positioned in a mask frame, with a product having a plurality of second detection marks so that each first detection mark is aligned with a second detection mark, comprising the steps of:i) positioning the product on a porous plate having registration pins thereon by fitting each of the registration pins through a corresponding hole in the product and securing the product in position by applying a vacuum to the product through the porous plate; ii) determining the position of each second detection mark on the product; iii) positioning the mask over the product by placing the mask frame on a mask supporting plate having at least two alignment pins thereon, said porous plate being a recessed portion of said mask supporting plate, by fitting each of said at least two alignment pins through a corresponding hole in the mask frame; iv) causing at least one movable first plunger to press against a first edge of the mask frame; v) causing two movable second plungers to press against a second edge of the mask frame, said second edge being perpendicular to said first edge; vi) determining the position of each first detection mark on the mask; vii) moving at least one first computer-controlled movable push plate against a third edge of the mask frame, said third edge being parallel to said first edge; viii) moving two second movable computer-controlled push plates against a fourth edge of the mask frame, said fourth edge being parallel to said second edge; ix) determining that, to align each first detection mark with one second detection mark, the mask must be moved toward said at least one first plunger by a first distance; x) determining that, to align each first detection mark with one second detection mark, the mask must be moved toward the second plungers by a second distance; xi) determining that, to align each first detection mark with one second detection mark, the mask must be rotated by a defined amount; xii) signaling said at least one first computer-controlled movable push plate to push the mask frame toward said at least one first plunger for said first distance; xiii) signaling all of said two second computer-controlled movable push plates to push the mask frame toward said second plungers for said second distance; and xiv) signaling said two second computer-controlled movable push plates to rotate the mask frame by said defined amount, wherein said rotation is accomplished by moving each of the movable push plates toward a corresponding one of the movable plungers, while simultaneously moving another of the second movable push plates away from its corresponding said second plungers, wherein the movement is calculated by geometry and trigonometry.