SnBi low-temperature thermal compression bonding method and structure based on elastic microsphere enhancement

Abstract

The application relates to the technical field of semiconductor packaging, in particular to a SnBi low-temperature hot-press bonding method and structure based on elastic microsphere enhancement, which comprises the following steps: S1, preparing SnBi-based composite solder paste containing metalized elastic microspheres, wherein the metalized elastic microspheres are uniformly distributed in the composite solder paste; S2, coating the composite solder paste to the pads of a substrate through a printing process; S3, aligning and placing a chip on the solder paste, and then preheating the chip through a heating head; S4, applying vertical pressure to the chip through the heating head and heating the chip to above the melting point of the composite solder paste, implementing hot-press bonding, so that the solder paste melts and the metalized elastic microspheres are compressed; and S5, forcibly cooling under the condition that the vertical pressure applied to the heating head is kept unchanged, and after the solder solidifies, the heating head removes the pressure, and the bonding is completed. Through the application, the problem that SnBi low-temperature solder joints are prone to brittle fracture and the problem that solder overflow leads to short circuit of the pads can be overcome.

Images