Thick film circuit medium temperature sintered silver electrode slurry for aluminium alloy substrate and preparation method thereof

Abstract

The invention discloses a thick film circuit medium temperature sintered silver electrode slurry for an aluminium alloy substrate and a preparation method thereof. The electrode slurry comprises an inorganic bonding phase, spherical silver powders, flake silver powders and an organic carrier. The inorganic bonding phase is formed by seven materials which comprise Bi2O3, B2O3, CaO, ZnO, K2O, a nucleating agent and a rare earth oxide. The organic carrier is formed by five materials which comprise an organic solvent, a polymer thickening agent, a dispersing agent, a deforming agent and a thixotropic agent. The preparation method of the electrode slurry comprises the steps of (a) inorganic adhesive phase preparation, (b) organic carrier preparation and (c) electrode slurry preparation. The electrode slurry has good thixotropy and fluidity and low sintering temperature, a sintered electrode has the advantages of a smooth structure, compactness, no crack, no pinhole, no bubble, lead-free and environment-friendliness, and at the same time the sintered electrode has the advantages of strong adhesion, aging resistance, low resistance and excellent printing characteristic and sintering characteristic.

Description

technical field [0001] The invention relates to the technical field of thick-film circuits, in particular to a medium-temperature sintered all-silver electrode paste for thick-film circuits for aluminum alloy substrates and a preparation method thereof. Background technique [0002] With the development of thick film circuit components towards multilayer and miniaturization, corresponding mechanical and thermal performance requirements are put forward for the substrate, especially the thermal conductivity requirements of the substrate; although BeO, Al 2 o 3 , AlN and other ceramic substrates have high thermal conductivity, but BeO substrates are limited in use due to their toxicity, and Al 2 o 3 And AlN substrates are limited in application due to poor mechanical properties and difficult assembly. The aluminum alloy substrate has properties such as low density, good ductility, good thermal conductivity, excellent cold and hot forming properties, and good toughness, which...

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Problems solved by technology

[0002] With the development of thick film circuit components towards multilayer and miniaturization, corresponding mechanical and thermal performance requirements are put forward for the substrate, especially the thermal conductivity requirements of the substrate; although BeO, Al 2 o 3 , AlN and other ceramic substrates have high thermal conductivity, but BeO substrates are limited in use due to their toxicity, and Al 2 o 3 and AlN substrates are limited in application due to poor mechanical properties and difficult assembly

The aluminum alloy substrate has properties such as low density, good ductility, good thermal conductivity, excellent cold and hot forming properties, and good toughness, which make it possible to be used as a substrate material; however, due to the high thermal expansion coefficient of the aluminum alloy substrate, at the same time The melting point is low (less than 660°C), so the high-temperature standard firing process (850°C) cannot be used; therefore, it is required that the corresponding electronic paste can only be sintered at a temperature lower than the melting temperature of aluminum alloy, and has good adhesion and matching Sexuality and screen printing characteristics make the development of aluminum-based electronic paste very difficult