Medium temperature sintering type electro-conduction slurry with lead-free glass powder and preparation method of medium temperature sintering type electro-conduction slurry

Abstract

The invention discloses a medium temperature sintering type electro-conduction slurry with lead-free glass powder and a preparation method of the medium temperature sintering type electrocondution slurry. The preparation method is characterized by comprising the steps of preparing an organic carrier, preparing the lead-free glass powder, preparing silver powder and preparing the electro-conduction slurry. The electro-conduction slurry comprises, by mass, 0 to 80% of micron-scale spherical silver powder, 5% to 70% of micron-scale flake silver powder, 2% to 25% of the lead-free glass powder and 0 to 25% of the organic carrier. The lead-free glass powder comprises, by mass, 25% to 75% of Bi2O3, 20% to 60% of B2O3, 0 to 20% of ZnO, 0 to 20% of Sb2O3, 0 to 10% of Al2O3 and 0 to 8% of alkali metal oxide. The organic carrier comprises, by mass, 50% to 80% of terpilenol, 10% to 40% ofbutyl carbitol acetic ester, 0 to 10% of tributyl citrate, 3% to 10% of ethocel, 0 to 2% of hydrogenated castor oil and 0 to 3% of addition agent.

Description

technical field [0001] The present invention relates to the preparation of a conductive paste, in particular discloses a medium-temperature sintered conductive paste containing lead-free glass powder and its preparation method, which is especially suitable for Al 2 o 3 The invention discloses silver paste for substrate thick-film conductive circuit, which belongs to the technical field of electronic materials. Background technique [0002] Because silver has excellent electrical and thermal conductivity, and lead-containing glass has low-temperature sintering performance and good bonding performance, lead-containing silver paste is used as microelectronic packaging, electrodes and interconnect materials, etc. A high-tech electronic functional material with technology in one. Most of the lead-based conductive pastes contain more than 70% PbO in the glass. Because lead pollutes the environment and is harmful to the human body, its application in silver pastes is severely res...

AI Technical Summary

Problems solved by technology

At present, spherical and flaky mixed silver powders are widely used in conductive adhesives, and there are few reports on the use of sintered silver pastes. S.P. Wu once used spherical and flaky silver powders with a mass ratio of 80:20 to make a high-temperature Conductive silver paste, after screen printing and sintering of the paste, the conductivity and adhesion strength have been greatly improved, but he did not study in detail the influence of different proportions of mixed silver powder on the performance of the silver paste

[0004] The current common sintered conductive pastes have the following deficiencies: (1) Although some conductive pastes have good overall performance, they contain chemical elements such as lead and chromium that are harmful to humans and the environment

(2) The slurry sintering temperature is relatively high, which does not meet the requirements of high efficiency and energy saving

(3) Poor mesh permeability during screen printing, unsatisfactory aspect ratio, high resistance after sintering and poor conductivity

(5) Poor solder resistance of conductive thick film after sintering

[0005] In order to meet the requirements of environmental protection, the Chinese patent application No. 200810039730.7 discloses a lead-free silver paste for high-temperature sintered automotive glass heating wire. The silver paste is made of lead-free glass powder by Bi 2 o 3 , SiO 2 , B 2 o 3 , ZnO, Al 2 o 3 、TiO 2 , Ag, etc., but its softening temperature is high, resulting in a high sintering temperature of the slurry, and the conductive thick film obtained after sintering the slurry has poor solder resistance

In order to improve the solder resistance of thick films and reduce the sintering temperature, the Chinese patent No. CN201010190544.0 discloses a thick film conductor paste used for alumina substrates. The silver powder of the paste is doped with a certain amount of palladium powder Or platinum powder, which can improve the corrosion resistance of the thick film during welding; in addition, Bi is added to the glass phase of the paste 2 o 3 The content of the paste reduces the sintering temperature of the paste, but the conductivity of the thick film after the paste is sintered is poor