A chip package solid crystal solder paste and its preparation method and use process

Abstract

The invention belongs to the technical field of electronic welding materials and discloses chip packaging die bonding tin paste and a preparation method and a using process thereof. The die bonding tin paste is prepared from, by weight percent, 82-88% of metal alloy powder and 12-18% of flux paste. The metal alloy powder is one of Sn96.5Ag3Cu0.5 and Sn89.5Sb10Ni0.5. The flux paste is prepared from, by weight percent, 20-30% of rosin resin, 35-45% of a solvent, 6-10% of dioctyl adipate, 2-4% of ethylene bisstearamide, 2-6% of 2-decyltetradecanoicacid, 4-8% of rosin amine polyoxylethylene ether, 1-3% of rheological additives and 5-10% of a moisture preserving agent. The die bonding tin paste can effectively guarantee the long-time operation uniformity of the die bonding process in an open environment, improves the oxidization resistance, reduces voidage and improves the electrical performance of semiconductor devices.

Description

technical field [0001] The invention belongs to the field of electronic soldering materials, in particular to the field of soldering materials for precision semiconductor packaging, and specifically relates to a chip packaging crystal-bonding solder paste and a preparation method and application process thereof. Background technique [0002] At present, precision semiconductor packaging includes integrated circuit packaging and light-emitting diode (LED) packaging. Package, POP) and other packaging methods. LED packaging includes COB (Chip on Board) and the popular new method of flip-chip packaging. The above traditional chip packaging materials are generally silver glue of epoxy resin system, and then heat treatment is carried out through silver glue until the chip is firmly fixed on the substrate, and then the wire bonding method is used to directly establish between the silicon chip and the substrate. Electrical connections. [0003] Since 2013, the semiconductor packa...

AI Technical Summary

Problems solved by technology

However, as the flip-chip packaging area becomes more and more precise and the size becomes smaller and smaller, it is easy to connect the glue when using traditional silver glue for die bonding, resulting in leakage, short circuit and other phenomena; in addition, the thermal conductivity of silver glue is low, and the soldering thermal resistance Large, which is not conducive to chip heat dissipation; and the epoxy resin in the silver glue is prone to aging and yellowing under high temperature and light conditions, thereby reducing the reliability of the package

Therefore, flip chip packaging needs to be soldered and packaged by eutectic method, but the cost of eutectic equipment will greatly increase the cost of finished product packaging. Another effective package is to solidify the crystal with solder paste, and then use ordinary reflow soldering to achieve soldering , to ensure its good electrical conductivity while achieving better thermal conductivity, greatly reducing interface thermal resistance, and greatly reducing packaging costs

[0004] In addition, the solder paste tin powder alloy currently used is SnAgCu, the particle size of the tin powder is in the range of 5-25 microns, the oxidation resistance of the solder paste is very poor, and it is easy to oxidize during the dispensing process, and the solder paste solvent used It is easy to volatilize, which will cause the viscosity of the die-bonding solder paste to gradually increase, which will affect the uniformity of dispensing

In the soldering process, due to the volatilization of solvents, the solder paste will not melt completely after soldering, or a large number of tin beads will appear, which will directly affect the soldering strength of the chip and cause short circuit leakage and other defects.

Images