CN103436100A - Conductive ink and preparation method thereof - Google Patents

Abstract

The invention relates to the field of conductive ink and in particular relates to conductive ink applied to ALN (aluminium nitride) substrates and a preparation method thereof. The conductive ink comprises the following components by mass percent: 60-80% of conductive metal powder, 4-8% of lead-free environment-friendly glass binders, 5-10% of organic resins, 10-20% of organic solvents and 1-2% of organic modifiers. The conductive ink has the beneficial effects that the conductive ink is well matched with the ALN substrates, is free from bubbles in the sintering process and has high activity of reaction with ALN and strong adhesion as the components of glass are exquisitely and optimally designed; by optimizing a conductive metal powder mixing system, the sintered metal film layer has good compactness, good conductivity, excellent weldability and excellent welding resistance and temperature impact resistance. All the materials adopted by the method for preparing the conductive ink are lead-free and have environment-friendly effect.

Description

A kind of electrically conductive ink and preparation method thereof

Technical field

The present invention relates to the electrically conductive ink field, particularly a kind of electrically conductive ink that is applied to the ALN substrate and preparation method thereof.

Background technology

At present, the ALN material, because it has environmental protection, high thermal conductivity, good insulativity and the good characteristics such as thermal expansivity of silicon coupling, has progressively substituted traditional Al in some high-end field ₂o ₃substrate, still, traditional electrically conductive ink is based on Al ₂o ₃substrate properties and developing, use therein glass adopts borosilicic acid bismuth system glass more, but bismuth oxide composition wherein easily reacts and produces gas with the ALN substrate in sintering process, makes the deterioration of conductive pattern performance.

In addition, du pont company is openly used TiB ₂as the surface reaction material, with ALN, generate Al ₂o ₃, B ₂o ₃as the interfaces transition phase, but the strength of joint that this method obtains is not high, TiB ₂decompose the B produced in sintering process ₂o ₃can be residual at film surface, the welding property of metallic diaphragm is caused to detrimentally affect, to be subject to the substrate performance impact larger for reaction bonded in addition, and the ALN substrate of different brands uses the strength of joint that electrically conductive ink of the same race obtains can be variant.

Summary of the invention

One of purpose of the present invention is to provide a kind of electrically conductive ink, this electrically conductive ink forms difform conductive pattern after by silk screen printing, oven dry, sintering on the ALN substrate, this conductive pattern is not only firm with the ALN substrate attachment, can not produce bubble, and welding property is good, can long-term stable operation.

Another object of the present invention is to provide the preparation method of above-mentioned electrically conductive ink.

Electrically conductive ink of the present invention, it forms and the quality percentage composition is: the metallic conduction powder is 60%～80%, leadless environment-friendly type glass binder is 4%～8%, organic resin is 5%～10%, and organic solvent is 10%～20%, and organic modifiers is 1%～2%.

Preferably, electrically conductive ink of the present invention, metallic conduction powder wherein is palladium-silver alloy powder and two kinds of mixed powders that the spherical silver powder of different diameter forms.

Preferably, electrically conductive ink of the present invention, the median size of metallic conduction powder wherein is 0.8～2.5 μ m, tap density is 2.1～2.5g/ml.

Preferably, electrically conductive ink of the present invention, described leadless environment-friendly type glass binder is BaO, CaO, MgO, CuO, ZnO, Al ₂o ₃, SiO ₂, P ₂o ₅in one or more.

Preferably, electrically conductive ink of the present invention, described organic resin is one or more in ethyl cellulose, Nitrocellulose, acrylic resin.

Preferably, electrically conductive ink of the present invention, described organic solvent is one or more in Terpineol 350, turps, butyl ether, diethylene glycol monobutyl ether.

Preferably, electrically conductive ink of the present invention, described organic modifiers is one or both in Yelkin TTS, class of department 85.

More preferably, the preparation method of above-mentioned electrically conductive ink, comprise the steps:

(1) take metallic conduction powder, crown glass binding agent, organic resin, organic solvent and organic modifiers stand-by;

(2) organic resin and organic modifiers are joined in organic solvent, put into 60 ℃ of-80 ℃ of water-bath heated and stirred, until dissolve fully, obtain organic carrier;

(3) metallic conduction powder, unorganic glass binding agent are joined in the organic carrier that step (2) makes, be ground to granularity and be less than 6 μ m, obtain electrically conductive ink.

Electrically conductive ink of the present invention, have good matching with the ALN substrate, not there will be bubble in sintering process, and glass ingredient is through the fine optimization design, large with the ALN reactive behavior, the strong adhesion of generation; By optimum combination conductive metal powder mixed system, the metallic diaphragm compactness after burning till is good, good conductivity, and weldability is good, has good soldering resistance and temperature resistance punching property.

The material that the method for preparing electrically conductive ink of the present invention adopts is all realized unleaded, environmental protection.

Embodiment

Embodiment 1.

Take 7g ethyl cellulose and 1g Yelkin TTS and join in the 18g Terpineol 350, then put into 75 ℃ of water-baths and heat and stirred until dissolving fully obtains organic carrier.

Taking respectively diameter is the silver powder of 1.8 μ m and 2.2 μ m, diameter is 1.9 μ m palladium-silver alloy powder 17.25g, 34.5g and 17.25g, (this diameter obtains with the laser particle analyzer test, lower with), and the BaO of 5g join mix and blend in organic carrier, then being ground to granularity with three-roll grinder is 5 μ m, the electrically conductive ink 1 obtained, test its physical parameter, the median size of hybrid metal conductive powder wherein is the mean value that 2.1 μ m(median sizes refer to three kinds of elemental metals diameiers, lower same), tap density is 2.2g/ml.

Embodiment 2.

The class of department 85 that takes respectively 5g ethyl cellulose and 5g Nitrocellulose and 2g joins in the mixed solution of 15g turps and 5g butyl carbitol, then puts into 75 ℃ of water-baths and heats and stirred until dissolving fully obtains organic carrier.

Take respectively the silver powder that diameter is 1.5 and 1.6, diameter is 1.4 palladium-silver alloy powder 24g, 12g and 24g, and 4g CaO and 4g P ₂o ₅join mix and blend in organic carrier, then with three-roll grinder, being ground to granularity is 4 μ m, and the electrically conductive ink 2 obtained, test its physical parameter, and the median size of hybrid metal conductive powder wherein is 1.5 μ m, and tap density is 2.4g/ml.

Embodiment 3.

The class of department 85 that takes respectively 4g Nitrocellulose and 4g acrylic resin and 2g joins in 12g Terpineol 350 and the terebinthine mixed solution of 4g, then puts into 75 ℃ of water-baths and heats and stirred, until dissolve fully, obtains organic carrier.

Take respectively the silver powder of diameter 1.0 and 1.1, diameter is that 1.3 palladium-silver alloy powder 22.67g, 22.67g and 22.67g and 3g MgO and 3g CuO join mix and blend in organic carrier, then being ground to granularity with three-roll grinder is 3 μ m, and the electrically conductive ink 3 obtained, test its physical parameter.The median size of hybrid metal conductive powder wherein is 1.5 μ m, and tap density is 2.5g/ml.

Embodiment 4.

The Yelkin TTS that takes respectively 3.33g Nitrocellulose and 1.67g acrylic resin and 1g joins in the 10g Terpineol 350, then puts into 75 ℃ of water-baths and heats and stirred until dissolving fully obtains organic carrier.

Take respectively the silver powder that diameter is 1.9 and 1.9, diameter is 1.6 palladium-silver alloy powder 54g, 16g and 16g, and ZnO, the SiO of 2g of 2g ₂join the organic carrier mix and blend, then with three-roll grinder, being ground to granularity is 5 μ m, and the electrically conductive ink 4 obtained, test its physical parameter, and the median size of hybrid metal conductive powder wherein is 1.6 μ m, and tap density is 2.3g/ml.

Embodiment 5.

The Yelkin TTS and the class of 0.5g department 85 that take respectively 8 ethyl cellulose and 0.5g join in 13.3g Terpineol 350 and the terebinthine mixed solution of 6.7g, then put into 75 ℃ of water-baths and heat and stirred until organic carrier is made in dissolving fully.

Take respectively the silver powder that diameter is 1.0 and 1.2, diameter is 1.1 palladium-silver alloy powder 26g, 26g and 13g, and 3g Al ₂o ₃join mix and blend in organic carrier with 3g CuO, then with three-roll grinder, being ground to granularity is 5 μ m, and the electrically conductive ink 5 obtained, test its physical parameter, and the median size of hybrid metal conductive powder wherein is 1.2 μ m, and tap density is 2.5g/ml.

Embodiment 6.

Take respectively 8g acrylic resin and 1g Yelkin TTS and join in the butyl ether of 18g, then put into 75 ℃ of water-baths and heat and stirred, until fully dissolve and make organic carrier.

Take respectively the silver powder that diameter is 1.7 and 1.5, diameter is 1.7 palladium-silver alloy powder 25g, 25g and 25g, reach 2gBaO, 2g CuO and 2g ZnO and join mix and blend in organic carrier, then being ground to granularity with three-roll grinder is 4 μ m, the electrically conductive ink 5 obtained, test its physical parameter, the median size of hybrid metal conductive powder wherein is 1.2 μ m, and tap density is 2.4g/ml.

Embodiment 7.

The electrically conductive ink 1-5 that embodiment 1-5 is prepared carries out performance test, and the concrete steps of test sample production method are as follows:

1, make one of the half tone of 4 2mm*2mm figures and 1 10mm*10mm figure;

2, clean, mix up automatic screen printing machine, load onto the ALN substrate;

3, take out and make intact electrically conductive ink 50 grams, be placed on printed pattern on automatic press;

4, take out the figure print and be placed in the Indoor Natural environment levelling 10 minutes, wherein room temperature remains on 5 ℃-25 ℃;

5, be placed on the interior 10-15 minute of oven dry of stoving oven of 100 ℃-150 ℃;

6, the substrate after the taking-up oven dry is placed in the continuous tunnel furnace that is provided with several warm areas and carries out sintering; Start to keep dropping to again in 8-10 minute the room temperature outlet to 850 ℃ of top temperatures accumulative total timing 25 minutes to 30 minutes from access mouth room temperature;

7, take out print from going out road junction, range estimation surfacing print smooth, that the surrounding sideline is neat is preliminary qualified print, and qualified print is carried out to following every test.

8, test.

(1) anti-erosion.

Hot-plate (250 ± 10 ℃) is spread soldering paste, by substrate be printed on the conductor item one facing to hot plate, first place 10S at every turn, substrate is cooling, then be put on hot plate when soldering paste melts, pick up substrate and check the conductor erosion condition, this,, for once, loops; Until conductor starts to be etched, record the cycle index data.

This printing ink is method welding mean value all >=4 times in due order, can adhere to 3 times and above for qualified.

(2) Weldability.

Hot-plate (250 ± 10 ℃) is spread soldering paste, by substrate be printed on slurry one facing to hot plate, be not less than 3S each weld interval, until soldering paste is covered with whole pulp surface fully; Result is as follows.

Each welding >=5S; Each welding >=3S is qualified.

(3) wicking experiment.

The one side level that substrate is printed on to slurry immerses molten tin bath (225 ± 10 ℃), keeps 10S/ time, until conductor starts to come off; Result is as follows.

This printing ink method test in due order corrodes mean value all >=5 times, can adhere to 3 times and above for qualified.

(4) pulling experiment.

At the solder joint area, be: on the AlN substrate pad of 2.0mm * 2.00mm, the phosphorus copper wire that weld diameter is 1.0mm, 250 ± 10 ℃ of welding temperatures, weld interval 3S; The solder joint area is about 4mm2, and stacked solder thickness is about 1mm.The pulling force of testing level and vertical direction, record the unit surface pulling force as follows respectively.

Former printing ink vertical tension >=22N, >=15N's is qualified; Former printing ink vertical tension >=26N, >=20N's is qualified.

Claims (8)

1. an electrically conductive ink, it forms and the quality percentage composition is: the metallic conduction powder is 60%～80%, the crown glass binding agent is 4%～8%, organic resin is 5%～10%, and organic solvent is 10%～20%, and organic modifiers is 1%～2%.

2. electrically conductive ink according to claim 1, is characterized in that described metallic conduction powder is the mixed powder that silver powder that two kinds of different diameters are spherical and palladium-silver alloy powder form.

3. electrically conductive ink according to claim 2, the median size that it is characterized in that the metallic conduction powder is 0.8～2.5 μ m, tap density is 2.1～2.5g/ml.

4. electrically conductive ink according to claim 1, is characterized in that described crown glass binding agent is BaO, CaO, MgO, CuO, ZnO, Al ₂o ₃, SiO ₂, P ₂o ₅in one or more.

5. electrically conductive ink according to claim 1, is characterized in that described organic resin is one or more in ethyl cellulose, Nitrocellulose, acrylic resin.

6. electrically conductive ink according to claim 1, is characterized in that described organic solvent is one or more in Terpineol 350, turps, butyl ether, diethylene glycol monobutyl ether.

7. electrically conductive ink according to claim 1, its feature with described organic modifiers be one or more in Yelkin TTS, class of department 85.

8. the preparation method of electrically conductive ink claimed in claim 1, is characterized in that comprising the steps:

(1) take metallic conduction powder, crown glass binding agent, organic resin, organic solvent and organic modifiers stand-by;

(2) organic resin and organic modifiers are joined in organic solvent, put into 60 ℃ of-80 ℃ of water-bath heated and stirred, until dissolve fully, obtain organic carrier;

(3) metallic conduction powder, unorganic glass binding agent are joined in the organic carrier that step (2) makes, be ground to granularity and be less than 6 μ m, obtain electrically conductive ink.