Patent ID: 6216937
Filing Date: 2001-04-17
Classification: B23K,H01L

Abstract:
Apparatus for removing at least one flip chip of a plurality of closely spaced flip chips having C4 joints on their faces connected to pads on a multi-chip module comprising:a selective flip chip removal assembly including a chip removal member and a tension mount having a top and four sides surrounding said multi-chip module and having at least one hole in its top aligned with a chip to be removed, said removal member comprising a block of a dimension smaller than an area of the back of the chip and a threaded stud fastened to the block at one end and to an adjustable tension element at the other end and extending through the hole in the top of a tension mount;bonding means for adhesively attaching said block to the back of the chip to be removed;tension means disposed around said stud and between the top of the tension mount and the tension element for applying a tensile force to said removing member greater than the surface tension of C4 joints while in a molten state; andheating means for heating the C4 joints to a temperature to place the C4 joints in a molten state, whereby the tension means causes the removing member to lift and separate the chip to be removed from the multi-chip module.