Patent GB-1495984-A (GB)
Title: Pick up apparatus
IPC: H05K13/04
Filed: 1975-10-28
Abstract: 1495984 Suction grippers INTERNATIONAL BUSINESS MACHINES CORP 28 Oct 1975 [20 Dec 1974] 44233/75 Heading B8H An apparatus for picking up one 19a of a plurality of semiconductor chips adhering to a carrier material 18, comprises a needle 33 movable through the material 18 to lift the selected chip for removal by a suction pencil 22, adjacent non-selected chips 19 being held down by a hold down ring 21 during such needle movement, the pencil 22 being engageable with the selected chip before such needle movement. The pencil assembly 14 comprises the pencil 22 vertically movable within a bore in a piston rod 121 between limits consistituted by interengagement of an upper shoulder on the pencil with a stepped upper housing 25, of the assembly 14, and interengagement of the top edge of the piston rod 121 with a tube 28 laterally extending from the pencil and through which pressure air or a vacuum is applied to the nose of the pencil through a passage 35 therein. The pencil is movable downwardly between the said limits by pressure air supplied through a pipe 27 to a chamber 38 in which a piston-like end 37 of the pencil 22 is reciprocable. The piston rod 121 is formed integrally with a piston 120 movable along the inside of a cylindrical housing 20 between upper and lower closure members 24, 23, the hold down ring 21 being formed integrally with the piston rod 121 below the lower closure member 23. The lower end of the pencil 22 is slidably guided in a bore in the hold down ring 21, and the lower end face of both the pencil and the ring 21 are covered by rubber 36, 42. In operation, once a chip carrier has placed a selected chip 19a in position over the needle housing 16 the pencil assembly 14 has been co-axially aligned with the needle 32, air is supplied to the chamber 38 to displace the pencil 22 downwardly until the tube 28 engages the piston rod 121, and air is supplied through the tube 28 and passage 35 to blow debris from the chip surface. Air is also supplied through a port 30 to an annular passage 48 in the housing 20, from where the air passes through passages 46a, 46b to an annular recess 44 in the upper closure member 24. The air in the recess 44 moves the piston 120 slowly downwardly whereupon air can move directly from the passage 48 into the space above the piston and the piston then descends rapidly, the air below the piston 120 exhausting to atmosphere through a port 31 in the cylinder 20. The exhausting is rapid via an annular passage 47 in the cylinder 20 until this passage becomes blocked by the piston whereafter the exhaust is restricted through a recess 43 and passages 45a, 45b in the lower closure member. A similar action takes place during raising of the piston 120 when air is supplied to port 31 and exhausted from port 30. During lowering of the piston 120, the pressure air supply to the pencil nose is changed to a vacuum supply to grip the chip 19a as the pencil engages said chip ahead of engagement of the surrounding chips by the hold down device 21. The needle 33 is thereafter cam lifted, and penetrates the material 18 to push the chip 19a and pencil 22 upwardly relative to the hold down ring 21, whereafter the ring 21 is lifted by the piston 120, and the needle lowered. The pencil assembly then moves to a chip depositing station before returning to receive a further chip newly positioned over the needle assembly.