International Business Machines Corporation

Walter Von Kaenel

Alfred A Stricker

Walter W Ficker

Thomas J Cochran

William G Rance

Albert H Buchmann

David E Lonser

A method and apparatus permitting accurate and repeatable steps of location and alignment of flimsy sheets during their transfer. A preferred embodiment comprises a sheet handler and method for aligning unfired ceramic green sheets used in multi-layer ceramic semiconductor packages. The thin flexible sheets are square or rectangular in shape and are provided with holes accurately punched in each corner thereof for alignment purposes. The sheets are moved by a vacuum input transfer head into orientation with a porous registration surface of an alignment fixture. The sheet is then trapped between opposed pressure zones emanating from the input transfer head and through the porous registration surface, respectively. With the sheet stabilized between the pressure zones four bullet-nosed alignment pins are raised from the registration surface into contact with the holes in the corners of the green sheet, thereby accurately aligning the sheet with respect to the alignment fixture. The input transfer head is then withdrawn and an output transfer head picks up the aligned sheet via vacuum means and transfers it to other processing locations. In an alternate embodiment the pressure zones are created between the output transfer head and the registration surface of the alignment fixture.

Method and apparatus for locating and aligning flimsy sheets

A vacuum pick up and transfer head adapted for handling flimsy sheets of material such as spacer sheet and uncured ceramic sheet commonly referred to as green sheet. The vacuum transfer head is of generally rectangular configuration having a sheet contacting lip having vacuum slots formed through the periphery thereof to hold the sheets in place by vacuum pressure. The center of the sheet contacting face is recessed whereby, with a sheet in place and acting as a diaphragm, a central vacuum chamber is also defined. A series of check valves are provided to control application of vacuum and positive pressure to the green sheet for picking the sheet up, retaining it and stripping it. A plurality of probes are provided in the handling head, adapted to selectively project through the sheet contacting surface for detecting green sheet and/or spacer sheet utilized inbetween layers of green sheet. These probes also can act as positive strippers when the head enters a green sheet spacer tray in the process of removing a sheet of spacer or green sheet.

Pick up and placement head for green sheet and spacer

Growing community of inventors

Pompano Beach, FL, United States of America

Walter Von Kaenel