Patent GB-1225323-A (GB)
IPC: H01L21/304
Filed: 1969-05-06
Abstract: 1,225,323. Grinding. HAMCO MACHINE & ELECTRONICS CORP. 6 May, 1969 [17 April, 1969], No. 23109/69. Heading B3D. A device for cutting a thin slice from an element 10, such as a silicon or germanium crystal, comprises a rotatable annular member 11 provided with a cutting edge 13 at the inner periphery thereof, and means for moving the element from a first position within the inner diameter of the member to a second position between the inner diameter and the outer periphery of the member. The member 11, the cutting-edge of which is formed of diamond grit, is secured between clamping rings 14, 15 and is tensioned by a ring 16 fixed to a cup-shaped member 17 rotatably mounted on a plate 18. A sleeve 20 is located within an opening 19 in the member 17 and supports a receptacle 21. The element 10 to be cut into thin slices is mounted in a pedestal 23 carried by a bracket 24 so as to be tiltable about a pivot 25 on a support 26 by an eccentric shaft 34 rotatable by an hydraulic actuator 30. The support 26 is movable by an hydraulic device 40 to move the element 10 between the first and second positions. A suction plate 50 is disposed within the receptacle and carried on an arm 51 movable about a pivot 52 by an hydraulic device 53 so as to position the plate in the position shown dotted in Fig. 2 to receive a slice cut from the element and move it to a transfer position aligned generally with the axis of the cutting member 11. A second suction plate 60 is carried by an arm 61 and is movable from the transfer position upwardly and sideways by movement of the arm about a pivot to a release position (shown dotted) for depositing the slice in a receptacle 73. The arm 61 is carried by a sleeve 62 which is raised and lowered by an hydraulic device 70, a pin-and-slot arrangement causing the pivotal movement of the arm. In operation, the element 10 to be cut is clamped by a solenoid to the pedestal and is aligned with the axis of the cutting member 11. The hydraulic device 40 is operated to move the support 26 so that the member is moved from the first to the second position and a slice is cut therefrom. Shortly before the end of the movement of the support, a vacuum is connected to plate 50 so that as the slice is cut it is held on the plate. The hydraulic device 53 is actuated to move the plate to the transfer position aligned with the axis of the cutting member and the hydraulic device 20 is actuated to move the plate 60 to the transfer position. Vacuum is applied to plate 60 as it is disconnected from plate 50 so that the slice is held on plate 60 which is then moved by device 20 to the release position wherein the slice is deposited in the receptacle 73. In order to avoid the cut end of the element 10 being marked by the cutting member during its return movement, the actuator 30 is operated to rotate eccentric shaft 34 and tilt the pedestal about the pivot 25. Hydraulic device 40 is then operated to return the element 10 to its first position and actuator 30 operated to re-position the pedestal. The element 10 is fed downwardly an amount corresponding to the thickness of a slice to be cut by rotation of a lead-screw 75 driven by a wormwheel and ratchet drive from a rack 77 movable by an hydraulic device 78. The machine is automatically controlled by a number of limit switches in an electric circuit.