PELLET BONDING

PURPOSE:To prevent an overflowed preform from reaching up to the surface of a pellet by a method wherein, when the pellet is bonded at the prescribed position on a substrate through a preform, high-pressure gas is sprayed on the side peripheral parts of the pellet. CONSTITUTION:A lead frame 1 is fed on a conveying stand 16 and is conveyed to a bonding position. Moreover, a silver paste 3 is coated on a tab 2 on the way to convey the lead frame 1 to the bonding position. If a positioning of the lead frame 1 is completed, a vacuum pump 14 is driven and a pellet 4 is attracted by a vacuum-drawing collet 12 through a hole 13. Then, the collet 12 is shifted to right over the tab 2 and the pellet 4 is press-placed on the tab coated with the silver paste 3 by the prescribed load. Moreover, this pellet bonding method features such a way that when the pellet is pressed, the drive of the vacuum pump 14 is stopped and is changed-over to the drive of a gas feeding pump 15 and gas (such inert gas as nitrogen gas and argon gas) is jetted through the hole 3 and also, the gas pressure is applied to the silver paste 3 so that the silver paste 3 to be overflowed on the periphery of the pellet when the pellet is pressed does not reach the surface of the pellet 4 along its side surfaces.