Preparation method of metal bump structure

Abstract

The invention discloses a preparation method of a metal bump structure. The preparation method comprises the steps of providing a substrate; forming an insulating block-up layer on the upper surface of the passivation layer of the substrate and the upper surface of part of the bonding pad; removing the insulating block-up layer at the preset position to enable the remaining insulating block-up layer to form an insulating block-up block, and covering the upper surfaces of the passivation layer, the insulating block-up block and part of the bonding pad with a seed layer; and forming a photoresist layer on the seed layer, then removing the photoresist layer at a preset position to form a photoresist layer pane which exposes the bonding pad outwards, forming a metal convex block in the photoresist layer pane in an electroplating mode, wherein part of the metal convex block is formed on the insulation block-up block, and the top of the metal convex block is provided with a concave part and a protruding part oppositely formed on the edge of the concave part. According to the preparation method of the metal bump structure disclosed by the embodiment of the invention, the opposite concave part is formed in the upper part of the metal bump through the arrangement of the insulating block-up block, so that the problem of short circuit between adjacent welding spots caused by pin fusion and overflow is effectively avoided.

Description

technical field [0001] The invention relates to the technical field of chip packaging, in particular to a method for preparing a metal bump structure. Background technique [0002] Flip Chip technology (Flip Chip), also known as "inverted chip packaging" or "inverted chip packaging method", is a kind of chip packaging technology. This packaging technology is different from the previous way of placing the chip on the substrate and then connecting the chip to the connection point on the substrate by wire bonding technology. Instead, long solder joints are formed on the chip connection points, and then the chip is turned over so that the solder joints are directly connected to the substrate. At present, flip chip technology has been widely used in microprocessor packaging, and has also become the mainstream packaging technology for graphics, special applications, and computer chipsets. In particular, representative examples of the flip-chip technology are Chip On Glass (COG) ...

AI Technical Summary

Problems solved by technology

In this bonding process, each solder joint in the chip and the corresponding pin on the substrate circuit need to be pressed into a eutectic structure under high temperature and high pressure conditions. If the material of the pin is melted and extended during this step, two solder joints will Points are shorted, which affects chip performance

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