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A method for connecting a high-power GTO module by means of pressureless sintering

A high-power, solder paste technology, applied in the field of low-temperature pressureless sintering of nano-silver solder paste, and large-area connection between GTO chips and molybdenum substrates, can solve the problems of lowering GTO reliability, complicated process, and high cost, and can improve the application temperature range , low process temperature and low thermal stress

Active Publication Date: 2015-01-28
TIANJIN UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

This technique is costly and the formation of intermetallic compounds at the interface reduces the reliability of the GTO
In addition, as the interconnection area increases, the process will be more complex

Method used

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  • A method for connecting a high-power GTO module by means of pressureless sintering
  • A method for connecting a high-power GTO module by means of pressureless sintering
  • A method for connecting a high-power GTO module by means of pressureless sintering

Examples

Experimental program
Comparison scheme
Effect test

example 1

[0030] The molybdenum substrate area is 708mm, the chip area is 700mm, the molybdenum surface is cleaned by plasma, and the cleaning time is 30min; the titanium film is plated on the molybdenum substrate, the coating power is 20W, and the time is 15min, followed by silver plating, the power is 20W, and the time is 30min. The film thickness is 260nm, and the silver film thickness is 100nm; the heat treatment temperature is 300°C, and the holding time is 240min. The microscopic morphology of the final surface silver plating layer is as follows: image 3 As shown, the energy spectrum of the coating is shown as Figure 4 shown. Nano-silver solder paste is used as the connection material between the chip and the substrate. The thickness of the solder paste is 50um, the sintering heating rate is 5°C / min, heated to 270°C, and kept for 15min. The mechanical performance test strength of the joint reaches 25MPa, and the final fracture occurs in the nano-silver paste layer, such as F...

example 2

[0032] Molybdenum substrate area is 708mm, chip area is 700mm, coating process: plasma cleaning molybdenum surface, cleaning time is 30min; coating titanium film on molybdenum substrate, coating power is 25W, time is 10min, followed by silver plating, power is 25W, time is 60min, The heat treatment temperature is 600°C, and the holding time is 120min. The thickness of the solder paste application is 90um, and the sintering temperature curve: the heating rate is 8°C / min, heated to 250°C, and kept for 30min. The entire packaging process is simple, and the final packaged GTO module has good heat dissipation and high reliability.

example 3

[0034] Molybdenum substrate area 708mm, chip area 700mm, coating process: plasma cleaning molybdenum surface, cleaning time is 30min; coating titanium film on molybdenum substrate, coating power is 30W, time is 15min, then silver plating, power is 30W, time is 80min, The heat treatment temperature is 900°C, and the holding time is 60 minutes. The thickness of the solder paste application is 90um, and the sintering temperature curve: the heating rate is 3°C / min, heated to 320°C, and kept for 5min. The entire packaging process is simple, and the final packaged GTO module has good heat dissipation and high reliability.

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Abstract

The invention discloses a method for connecting a high-power GTO module by means of pressureless sintering. In the method, silver plating is implemented on a surface of a molybdenum substrate by plating titanium on the surface as an intermediate metal layer by means of a magnetron sputtering apparatus, and then the connection of large areas between a chip and the substrate is realized by means of pressureless sintering at a lower temperature with a nano-silver soldering paste. The detailed steps of the method are described as follows: plasma cleaning the molybdenum substrate in order to clean and activate the surface thereof; plating titanium and silver successively by means of the magnetron sputtering apparatus, and heat treating the plated molybdenum substrate under nitrogen or an inert gas to ensure the stability of the plated films. The thickness of the plated silver film can be adjusted by a plating power and a plating time. Plating titanium as a metal transition layer may overcome the problem that the silver cannot be plated on the molybdenum substrate due to the fact that both silver solid solution and molybdenum solid solution are immiscible. Silver joint after the sintering has a high electrical conductivity (4.10*10<7>S m<-1>) and a high heat-conducting property (240W K<-1>m<-1>), and can be high temperature resistant (<960 DEG C) so as to further improve the temperature range of the module application.

Description

technical field [0001] The invention relates to the technical field of packaging of power electronic devices, in particular to the surface modification of molybdenum substrates in the packaging process of high-power turn-off thyristors (GTOs), and the use of nano-silver solder paste for low-temperature pressure-free sintering to realize the large size of GTO chips and molybdenum substrates. method of area connection. Background technique [0002] The turn-off thyristor has a large operating current and plays an important role in large-capacity frequency converters, but the interconnection between the chip and the molybdenum substrate has always been a difficult problem in the manufacturing process. Due to the limitation of temperature and chip load, the existing technology is mainly vacuum diffusion interconnection. The coated chip and the coated substrate are kept under appropriate pressure and temperature for a long time, and the interconnection is realized through interfa...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01L21/60
CPCH01L24/03H01L24/05H01L2924/01047H01L2924/01042H01L2224/8384
Inventor 梅云辉李万里陆国权李欣
Owner TIANJIN UNIV