Laser printing method for microbumps in packaging three-dimensional integrated circuit

Abstract

The present invention provides a micro-bump laser printing method for three-dimensional integrated circuit packaging. The method comprises: placing a chiplet having pre-formed micro-pads on a chuck disclosed below a donor film; and irradiating the donor film in alignment using a pulsed laser such that the donor film locally molts and ejects metal droplets, wherein the metal droplets deposit on surfaces of the micro-pads, and cool to solidify, thereby forming an array of metal micro-bumps. The present invention forms micro-bumps by laser direct-write printing without using a mask, thereby achieving a simplified process flow and a short period. Micro-bump arrays having different sizes and positional distributions are formed by changing a size of a laser spot and irradiation positions on the donor film, thereby achieving high process flexibility. Micro-bumps having different compositions are formed by replacing a material of the donor film, thereby achieving a wide material applicability.

Dependencies are inferred from the claim text.