Manufacturing method of nail head gold bump

Abstract

The invention relates to a manufacturing method of a nail head gold bump, comprising the following steps of: establishing an exact energy equation on the relation between a gold wire and a gold ball; vertically moving a riving knife upwards after a first welding point is finished, wherein an opened wire clip makes the gold wire slide in the riving knife and reach the expected height, i.e. the height of a welded gold bump; moving the riving knife at a certain speed rapidly rightwards, and keeping a slight connection between the gold wire and the gold ball; moving the riving knife upwards for a section of distance, and then closing the wire clip; continuously moving the riving knife upwards till the gold wire is pulled apart; and moving the riving knife to a place above a next bonding point to discharge and form a ball, and carrying out a next bonding circulation process. In the manufacturing method of the nail head gold bump disclosed by the invention, the sizes of formed balls are controlled, thus the coplanarity of the bump is improved, the bonding point is prevented from failure, and a high-speed high-precision manufacturing process of the gold bump is obtained.

Description

technical field [0001] The invention relates to a welding method in a microelectronic package, in particular to a method for preparing a nail head gold bump. Background technique [0002] At present, gold, copper, and aluminum are excellent materials for realizing chip-level interconnection technology in integrated circuit packaging. The most common and most successful metal lead used in gold bump bonding is gold wire. Gold has the advantages of high electrical conductivity, corrosion resistance, good toughness, etc., and the technology is mature and the process stability is good. However, the gold bump welding technology also has certain limitations: it is not suitable for high-density packaging; the material cost is very expensive; and intermetallic compounds are easily generated between the gold bonding point and the aluminum metallization layer under high temperature conditions. These intermetallic compounds have high contact resistance and high brittleness, and are pr...

AI Technical Summary

Problems solved by technology

However, the gold bump welding technology also has certain limitations: it is not suitable for high-density packaging; the material cost is very expensive; intermetallic compounds are easily generated between the gold bonding point and the aluminum metallization layer under high temperature conditions

If non-coplanarity is significant (for example, some bumps are taller than others), those lower bumps will not be able to contact the package substrate during flip-chip bonding, requiring significantly increased bond force and bond strength. time, so that all the bumps can be successfully bonded, but the fluctuation of bump height will lead to uneven distribution of bump loading force, chip breakage or open circuit, on the contrary, the improvement of bump coplanarity will reduce the impact on chip and substrate stress

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