| Low temperature co-fired ceramic technology has many advantages,such as high integration,Low dielectric loss,good high frequency characteristic,etc..When the circuit is printed on the cast-in-place ceramic plate by using the printing equipment,the printing pattern will be incomplete,the surface of the printing pattern will have silk-like stripes,and the thickness of the printing film will be uneven,thus affect the print line pass rate.Ink-jet printing technology has the advantages of non-contact,non-mask and fast and accurate deposition of conductive ink,and can minimize surface pollution and ink waste.By ink-jet printing nano-copper conductive ink can obtain high surface accuracy,edge clear and flat and print layer thickness uniform printed conductive circuit.Ink jet printing can provide an effective solution to the problems of conductive circuit printing in low temperature co-fired ceramic technology,and has great research and application prospects in the printing of conductive circuit.In this work,stable and dispersed copper conductive nano-ink suitable for inkjet printer printing was prepared from 50 nm copper nanoparticles.Firstly,the effects of different dispersants and the amount of dispersants on the rheological properties of ink were studied Then,commercial modified inkjet printer were used to test the printing performance of the prepared nano-sized copper conductive ink,and the effect of different sintering methods on the electrical conductivity of the printed pattern was studied.(1)In this study,the optimum amount of dispersant was determined by selecting the suitable dispersant species,the suitable mixed organic solvent was selected as the dispersing medium,and the optimum proportion of solvent was determined,nano copper conductive ink suitable for inkjet printing was prepared.Firstly,the influence of dispersant type and addition amount on ink rheological properties was studied.The results showed that the ink had the best dispersing effect when the dispersant was CPD-03 and the addition amount of dispersant was0.75%And the solvent is ethanol and glycol mixed solvent,adding ratio is 3:1,the prepared ink has the best dispersion effect,and finally,the nano-copper conductive ink suitable for ink-jet printing is prepared,the solid content of the ink is 5 vol%,the viscosity is 2.89 m Pa·s,the surface tension is 25.96 m N/m and the particle size is 206 nm.(2)Based on the prepared ink,a practical printing effect of the ink on the ceramic substrate was studied,including the determination of the minimum line width and the relationship between the number of printing layers and the actual line width,the minimum line width is90μm,and the relationship between print layer number and print layer thickness is determined.The average layer thickness of ink-jet printed conductive pattern is 250 nm.(3)Considering that the particle size of copper nanoparticles is very small,the specific surface area and the surface energy are very large,so the oxidation of copper nanoparticles is very serious,so the intense pulsed light(IPL)sintering is chosen,the best sintered radiant energy density was determined to be 9 J/cm~2 based on the apparent phenomena and electrical properties of the sintered copper films.The internal micro-structure of the sintered copper films was observed by Scanning electron microscope,the density and conductivity of printed copper film are closely related to the number of printed layers.The optimum number of printed layers is 9,and the square resistance of printed copper film is 33.26 mΩ/sq. |
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