A packaging material structure layer for front connection of high junction temperature power module chips and its manufacturing method

Abstract

The invention discloses a method for manufacturing a packaging material structure layer for front connection of a high junction temperature power module chip, comprising the following steps: S01, making a preformed planar copper sheet or copper bar, the width of which is smaller than the width of a metal pad on the front side of the chip; S02, print the sintered silver paste on the surface of the copper sheet or copper bar by printing process to form a layer of silver film; S03, solidify the printed copper sheet or copper bar in an oven to form a copper sheet silver film composite material. The present invention also provides a packaging material structure layer for front-side connection of high junction temperature power module chips, which is produced by the above manufacturing method for packaging material structure layer for high junction temperature power module chip front connection. The present invention provides a packaging material structure layer for front-side connection of high-junction temperature power module chips and a manufacturing method thereof, which is conducive to realizing mass production, and is used for front-side bonding of high-junction temperature power module chips, and realizes a temperature above 400 degrees Celsius. In the application environment of high junction temperature chips.

Description

technical field [0001] The invention relates to a packaging material structure layer for front connection of high junction temperature power module chips and a manufacturing method thereof, belonging to the technical field of packaging of power semiconductor devices. Background technique [0002] The power module can withstand high voltage and provide high current, and is easy to control. It is an important power device for motor control and power inverter. The power chip is welded on the copper-clad ceramic board (DBC) with solder (solder paste or solder sheet), sintered silver, and the front side of the chip is conducted by aluminum wire bonding. In actual use, especially silicon carbide (SiC) chips and gallium nitride (GaN) chips with high junction temperature (greater than or equal to 300 degrees Celsius), a chip front bonding material with high temperature resistance and high elastic modulus is required; due to the working of IGBT The frequency is high, and the tempera...

AI Technical Summary

Problems solved by technology

For high junction temperature working environment, ordinary bonding aluminum wires will fall off and disconnect, which will lead to premature failure of individual chips and affect the long-term reliability of the module

[0003] The mainstream bonding material of traditional power chips is aluminum bonding wire, the melting point of pure aluminum is 660 degrees Celsius, and the wire diameter ranges from 8 to 20 mils, but the wire diameter that is bonded to the chip to conduct current is mainly 15 mil (375um). ;The aluminum wire is connected to the front of the chip through ultrasonic vibration and friction through ultrasonic bonding equipment, and is used to connect the conduction current; however, the current carrying capacity of a single 15mil aluminum wire is about 10A, and the longer the arc, the lower the carrying capacity

In addition, the copper wire bonding on the front of the chip is an ideal material that can replace the aluminum wire bonding, but the hardness of the copper wire is more than twice that of the aluminum wire, and the Al and Ag metallization layers bonded to the traditional chip front are very easy Damage to the chip; some studies have shown that copper wire bonding can be achieved by performing copper metallization on the chip surface, but the formation of a copper metallization layer that can be effectively bonded takes a long time and is extremely expensive, and is not suitable for industrialization at present; The research institution invented the DTS technical solution. By using the sintered silver process to connect a certain thickness of copper thin film on the front of the chip, it can replace the production of copper metallization layer for copper wire bonding. At present, industrialization can be realized, but the cost of equipment and materials is relatively high; There are also research institutions that use Sn-based solder to connect thicker copper terminals on the front of the chip, or DBC to form an effective connection for the current on the front of the chip. However, Sn-based solder is suitable for ordinary chips, and the process is more complicated.

[0004] The current carrying capacity of a single aluminum wire bonded by aluminum wire is about 10A. The longer the arc is, the lower the carrying capacity is. When the device is short-circuited, the bonding wire cannot withstand the large current and fuses, resulting in a short circuit. In a high-voltage environment, it is easy to cause the module to explode.

In addition, the copper wire bonding on the front of the chip is an ideal material that can replace the aluminum wire bonding, but the hardness of the copper wire is more than twice that of the aluminum wire, and the Al and Ag metallization layers bonded to the traditional chip front are very easy Damage to the chip; some studies have shown that copper wire bonding can be achieved by performing copper metallization on the chip surface, but the formation of a copper metallization layer that can be effectively bonded takes a long time and is extremely expensive, and is not suitable for industrialization at present; The research institution invented the DTS technical solution. By using the sintered silver process to connect a certain thickness of copper thin film on the front of the chip, it can replace the production of copper metallization layer for copper wire bonding. At present, industrialization can be realized, but the cost of equipment and materials is relatively high; There are also research institutions that use Sn-based solder to connect thicker copper terminals on the front of the chip, or DBC to form an effective connection for the current on the front of the chip. However, Sn-based solder is suitable for ordinary chips, and the process is more complicated.

Images