| 摘要 |
PURPOSE:To prevent the soft error of a highly integrated dynamic RAM and the crack phenomenon of a semiconductor chip, by obstructing alpha-particles with a comparatively thin polyimide or Si resin film. CONSTITUTION:A semiconductor chip 2 is bonded on a lead frame 1 by applying a die bonder, and bonding pads arranged on the respective surfaces of the chip 2 and the frame 1 are connected by gold wires 3. The surfaces of the chip 2 is coated with a resin film 4, and a thin lead foil 6 is stuck on the surface of the resin film 4 by the die bonder, and the like, provided with a vacuum equipment. In the case where the range Rj of alpha-particle in the lead foil 6 is calculated from the range Rair in the air, the effective atomic weight Aj of the lead foil 6 is given by an expression 1, where rhoj is the density of lead. Therefore, the alpha-particles emitted form a package 5 are surely obstructed with a comparatively thin resin film 4 and the lead foil 6, and the soft error of a semiconductor device is prevented, and further the crack phenomenon of the chip 2 is also prevented. |
