Metal bump packaging structure and manufacturing method thereof

Abstract

Embodiments of the present invention provide a metal bump packaging structure and a preparation method thereof, which relate to the field of semiconductor packaging technology, and a metal bump packaging structure includes a substrate chip, a conductive pad, a protective layer, a metal conductive layer, and a welding bump , the surface of the protective layer has a first stepped surface and a second stepped surface, the first stepped surface and the second stepped surface are connected by a slope, and at least one first drainage groove is arranged on the slope. The present invention can more effectively reduce the liquid residue during etching of the metal conductive layer area at the bottom of the welding protrusion by setting the first drainage groove, thereby avoiding the problem of undercut openings in the metal conductive layer area at the bottom of the welding protrusion, and at the same time enabling The protective layer has a certain deformation margin in the horizontal direction, which can play a buffer role. At the same time, the surface roughness of the protective layer can be increased by opening the first drainage groove, thereby improving the bonding strength between the underfill and the protective layer, and improving the structural stability of the product.

Description

technical field [0001] The invention relates to the technical field of semiconductor packaging, in particular to a metal bump packaging structure and a preparation method thereof. Background technique [0002] With the rapid development of the semiconductor industry, the flip-chip packaging structure is widely used in the semiconductor industry, and the flip-chip packaging uses bumps to electrically connect the chip and the substrate. The bump includes a copper pillar, a metal layer (UBM: under bumpmetalization), a protective layer (Polyimide), and a tin cap (Sn Cap). After the metal layer UBM is fabricated, the excess metal layer needs to be etched and removed. Because the polyimide material is extremely easy to absorb water, the etchant on the UBM sidewall at the bottom of the metal pillar remains, resulting in excessive corrosion undercut openings at the bottom of the copper pillar bump. When the bump chip is tested for reliability, the copper pillar bump exists drop pro...

AI Technical Summary

Problems solved by technology

The bump includes a copper pillar, a metal layer (UBM: under bumpmetalization), a protective layer (Polyimide), and a tin cap (Sn Cap). After the metal layer UBM is fabricated, the excess metal layer needs to be etched and removed. Because the polyimide material is extremely easy to absorb water, the etchant on the UBM sidewall at the bottom of the metal pillar remains, resulting in excessive corrosion undercut openings at the bottom of the copper pillar bump. When the bump chip is tested for reliability, the copper pillar bump exists drop problem

[0003] In addition, in the packaging process for flip-chip copper pillar bumps, as the distance between the flip-chip soldering and the substrate becomes smaller and smaller, underfill glue is often used to fill and protect the bottom of the flip-chip. , in order to increase the bonding strength between the underfill glue and the chip surface protection layer, plasma bombardment of the organic surface is often used to improve the roughness of the organic surface and improve the bonding strength of the underfill glue. The process is complex

However, if silicon nitride or silicon nitride is used as the protective layer, the plasma bombardment has a poor effect on the surface roughness, resulting in a decrease in the bonding strength between the underfill and the protective layer, which is not conducive to the stability of the product.

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