Abstract: The positioning of mesh side features in a stencil mask are controlled to produce a mask which possesses high structural integrity and which exhibits a low service life. Mesh side feature control also eliminates certain unnecessary design side channels and mesh side via openings. Mesh side feature placement at T-shaped design side junctions is also controlled to produce a more uniform distribution of material which is screened through the stencil mask.

Abstract: A test pattern including an aperture image and a line image including a plurality of parallel lines, forming a measurement graticule, overlapping the aperture image, permits determination of dimensions for correction of alignment of image centerlines by inspection rather than complex measurement with stationary optical instruments. Since the line pattern preferably includes a plurality of parallel lines of predetermined width and separated by a predetermined spacing, the line image can be made to overlie the aperture image without obscuring features of the aperture image which are significant to determination of the alignment correction dimension.

Abstract: An apparatus is provided for positioning a workpiece with high accuracy and repeatably positioning the workpiece with similar accuracy while avoiding further manual alignment operations. Tapered pins, movable axially against a spring, are used to support a registration frame above the workpiece and allow attachment of the registration frame to the workpiece with high accuracy after initial manual positioning of the workpiece. After attachment of the registration frame to the workpiece, the use of similar, spring-loaded, tapered pins assures accuracy of positioning without further manual alignment. The axial motion of the pins is particularly advantageous during alignment of a plurality of workpieces in stacks and for processes requiring two-sided registration. During the alignment operation, a vacuum block is relatively movable on a base block and a workpiece immobilized on the vacuum block by a vacuum selectively applied to a portion thereof.