Effect of Ceramic Capillary Parameters on Bonded Morphology and Strength

Abstract

The effects of the geometry parameters of a ceramic cleaver on the morphology of ball and second bonded points were studied using an automatic wire bonder, push pull tester, scanning electron microscope, ceramic capillary with different geometric parameters and φ25.4 μmAg-5Au bonding alloy wire, etc. The result shows that when the inner hole diameter (IHD) of the ceramic capillary is 1.3 times the diameter of the alloy wire (33 μm), the neck morphology of the ball bonded point (first bonded point) meet the requirements. The neck of the ball bonded point appeared to fracture when the IHD is 26 μm; The neck of the ball bonded point appeared as an irregular shape when the IHD is 41 μm. When the inner cutting angle diameter (ICAD) is 64 μm, the size of the mashed ball diameter (MBD) is qualified. When the ICAD is 51 μm, the MBD is too large and mashed ball overflows the pad. When the ICAD is 76 μm, the ball bonded point is too high. When the inner cutting bevel angle (ICBA) is 100°, the MBD size meets the requirements of the pad. When the ICBA was reduced to 70°, the ball bonded point is eccentric. When the ICBA was increased to 120°, the MBD is too large and is connected to the adjacent pad contact. The size of the fish tail of the second bonded point (second bonded point) changed in the same direction as the tip diameter (TD) changes. When the TD is 178 μm, the fish tail shape is regular and symmetrical. When the working face angle (WFA) is 8° and the outer circular radius (OCR) is equal to the diameter of the alloy wire (25.4 μm), the fish tail shape is regular. When the WFA is higher than 11° or the OCR is higher than 30 μm, the fish tail will appear as virtual welding, and when the WFA is less than 4°, the fish tail of the second bonded point will break due to thinning. When the OCR is less than 20 μm, the fish tail of the second bonded point is too long and causes a short circuit.