Patent GB-1292827-A (GB)
Title: Methods and apparatus for photo-optical manufacture of semiconductor products
IPC: H01L21/00
Filed: 1969-11-11
Abstract: 1292827 Photographic apparatus TELEDYNE Inc 11 Nov 1969 [25 Nov 1968] 55159/69 Heading G2A In photographic step and repeat apparatus utilized in the production of semi-conductor arrays on a wafer, the photo-masks for e.g. contact printing the wafer, are each produced by reducing an appropriate original 12 supported by a glass plate 20 to the final image size in one optical reduction step, the reduced image being printed on to a photo-sensitive plate 54 which is continuously moved, exposures being effected by virtue of lines of a grid 72 being sensed and so triggering a flash-lamp 30. Initially a beam splitter 48 is removed so light passing through the original 12 is reflected by a mirror 50 into a reducing lens 52 and thence on to the lower surface of the plate 54. Before reaching the original 12 light from the lamp 30 is reflected by mirrors 34, 36 through a liquid filled condensing lens 40. Before any exposures are made focus is checked by utilizing a focusing slide and a microscope 74 with the grid removed. The plate 54 and grid 72 are mounted on a carriage 64 movable in two perpendicular directions, but is normally moved in one such direction only to expose a row of images on the plate 54 each time a photo-cell 76 in the microscope 74 senses either every grid ruling or every n<SP>th</SP> grid line (depending on how the apparatus is arranged). In situations where longer exposure is required, the carriage 64 is stopped during each exposure. After the traverse of each line of exposures, the carriage is stepped in the other perpendicular direction, and the next line of exposures made in the reverse direction. After all the lines have been exposed, the photo-plate is removed and processed, while a new original and a new photoplate are inserted and the sequence repeated for as many (e.g. six) photo-plates as are required for a given semi-conductor device. Using the same grid 72 will ensure accurate registering of the photo-plate images. The completed photo-plates are used to fabricate wafers which are tested by contact probers, any defective component of the wafers being marked. A tested wafer is then placed in the position occupied by the plate 54 while the original support carries an inter-connection network which it is desired to imprint upon the wafer, e.g. for shorting out defective components, a suitable mask being selectively exposed to the defective areas. Alternatively, the beam splitter 48 is inserted and the wafer (80) Fig.2 (not shown) is held in position beneath the beam splitter by suction. Light from a lamp 86 reaches the wafer (80) through the beam splitter 48 and a lens 92, and is reflected back by the wafer (80) and members 92, 48 on to the supporting plate 20 which carries an opaque surface 12 on which an enlarged image of the wafer is projected. The surface 12 is then cut in the appropriate places to correspond to the desired inter-connection pattern, the lamp 86 is turned off and the wafer (80) exposed to this pattern by the lamp 30. In another embodiment Fig. 3 (not shown), step and repeat creation of patterns are undertaken while reading test information directly encoded on the wafer.