CN104934099A - Printed circuit board silver paste with low silver content and preparation method thereof - Google Patents

Abstract

A printed circuit board silver paste with low silver content comprises the following raw materials by weight: 40-50 parts of 1-10-micron silver powder, 15-20 parts of silver-coated glass powder, 2-4 parts of nickel-coated copper powder, 1-2 parts of benzotriazole, 6-8 parts of glass powder, 1-3 parts of nano carbon, 7-10 parts of ethyl cellulose, 7-9 parts of butyl carbitol acetat, 1-2 parts of povidone, 1-2 parts of diisobutyl phthalate, 4-6 parts of ethanol, 3-5 parts of castor oil, and 5-8 parts of isobutanol. Through the use of silver-coated glass powder, nickel-coated copper powder and nano carbon, the electrical conductivity of the silver paste is improved, and the consumption of silver powder is reduced. Through the use of silver-coated glass powder, the wettability and surface smoothness of the paste are improved, and the cohesiveness is improved. Through the use of benzotriazole, metal powder is not easy to oxidize in the manufacturing process at high temperature, and good electrical conductivity is maintained. The production process of the silver paste is unique, and silver powder gathering and the influence thereof on the electrical conductivity can be prevented. The glass powder of the invention contains no lead, causes no pollution to the environment, and has low melting point and good cohesiveness.

Description

Printed circuit board (PCB) silver slurry of a kind of low silver content and preparation method thereof

Technical field

The invention belongs to electric slurry technical field, printed circuit board (PCB) silver slurry particularly relating to a kind of low silver content and preparation method thereof.

Background technology

In modern microelectronic industry, people require more and more higher to electronic devices and components, production adopts procedure more, standardization is carried out reducing costs, printed circuit board (PCB) (PCB) is exactly that this demand being applicable to microelectronics industry is born, match with the electric slurry such as resistance slurry, grout slurry and printed circuit board (PCB) (PCB) with regard to the conductor paste of the new requirement of demand, electrode slurry, dielectric paste accordingly, the research carrying out new conductor paste is also just imperative.

In general, the main component of electric slurry includes function mutually as metal, noble metal powder etc., inorganic binder as glass powder, oxide powder etc., organic binder bond, other solvent and additive.Usually, function in electric slurry plays electric action mutually, have good electric conductivity, is generally served as by metal dust or noble metal powder, conventional metal dust has copper powder, aluminium powder, zinc powder, nickel powder etc., and conventional precious metal powder has bronze, silver powder, platinum powder, palladium powder etc.Inorganic binder plays fixing electric slurry to base material, and generally served as by oxide powder and glass powder, but this composition is lower at the proportion of electric slurry, what have does not even have; Organic binder bond mainly works to make slurry have certain shape, is easy to printing or coating, mainly contain macromolecule resin, Small molecular resin etc. to serve as, along with this part effect in electric slurry of progress of chemical industry technology is more and more outstanding, especially, when being applied to silk screen printing, the composition changing organic binder bond just can change the printing of electric slurry, drying, sintering character.

In existing electric slurry field, it is high that silver system slurry has conductance, stable performance, with the feature such as substrate bond strength is large, is widely used in the production of the electronic devices and components such as integrated circuit, multi-chip module, thin film switch.But silver is precious metal, and cost is higher, and the silver powder major part in existing silver paste is micron-sized powder, and the thicknesses of layers, printing performance etc. of its slurry made have significant limitation for present high-end precision instrument; On the other hand, the conductive copper paste of the many employing printings of printed circuit board (PCB) in the past makes conducting wire, but it is easily oxidized to there is conductive copper paste, reduces the useful life of printed circuit board (PCB), and conductive copper paste can not be printed as meticulousr circuit.Therefore need the size of metal dust in research electrocondution slurry, shape, kind to realize the object reducing costs, improve conductance, improve printing accuracy.

Binding agent in conductive silver paste has a significant impact for the rate of finished products of circuit printing, such as the volatility etc. of viscosity, caking property, adhesive force, levelability, film forming, solvent all can impact the printing performance of circuit, there is pore, the phenomenons such as open circuit, also there will be glassy phase after organic substance has volatilized sometimes not yet to start to melt, the phenomenon causing conducting wire to come off from stock, makes conducting wire scrap, and therefore the performance need of organic binder bond improves.

A lot of inorganic binder adopts glass dust at present, glass dust is made up of the material such as metal oxide, silica, if fusing point is too high, also occur organic substance volatilized after glassy phase not yet start melt, the phenomenon causing the conducting wire obtained by conductive silver paste to come off from stock, makes conducting wire scrap; And a lot of containing harmful substances such as lead in current glass dust, unfavorable to environment, therefore need to develop the more excellent glass dust of performance.

Summary of the invention

Printed circuit board (PCB) silver slurry that the object of the present invention is to provide a kind of low silver content and preparation method thereof, the consumption of silver powder saved by this silver slurry, and caking property is good, good conductivity.

Technical scheme of the present invention is as follows:

A kind of printed circuit board (PCB) silver slurry of low silver content, is characterized in that being made up of the raw material of following weight portion: 1-10 μm of silver powder 40-50, silver-colored bag glass dust 15-20, nickel coated copper powder 2-4, BTA 1-2, glass dust 6-8, nano-sized carbon 1-3, ethyl cellulose 7-10, butyl carbitol acetate 7-9, PVP 1-2, diisobutyl phthalate 1-2, ethanol 4-6, castor oil 3-5, isobutanol 5-8;

Described glass dust is made up of the raw material of following weight portion: borax 15-17, Si0 ₂6-9, Bi ₂0 ₃20-25, A1 ₂0 ₃5-8, Li ₂0 3-5, MgO3-6, NaF2-4, Ti0 ₂3-6, ZnO4-7, K ₂o1-2, anoxic cerium oxide 1-2, nepheline powder 2-4, nanometer jade powder 2-5; Preparation method is: by borax, Si0 ₂, Bi20 ₃, A1 ₂0 ₃, Li ₂0, MgO, NaF, Ti0 ₂, ZnO, K ₂o, anoxic cerium oxide mix, put into crucible and become liquid 1100-1400 DEG C of heat fused, vacuum defoamation is carried out after stirring, vacuum degree is 0.10-0.14MPa, and inclined heated plate is 6-9 minute, then pours in mould and shape, carry out shrend again, send into pulverizing in ball mill, sieve, obtain 2-6 μm of powder, then mix with nepheline powder, nanometer jade powder, to obtain final product.

The preparation method of the printed circuit board (PCB) silver slurry of described low silver content, is characterized in that comprising the following steps:

(1) by butyl carbitol acetate, diisobutyl phthalate, castor oil, isobutanol mixing, add ethyl cellulose, be heated to 75-80 DEG C, be stirred to resin and all dissolve, filter with 500 object gauzes, removing impurity obtains organic carrier;

(2) ethanol is mixed with PVP, BTA, nano-sized carbon is added under stirring at 5000-7000 rev/min, stir 10-20 minute, mix with 1-10 μm of silver powder, silver-colored bag glass dust, nickel coated copper powder again, stir 10-20 minute, add in organic carrier together with other residual componentss again, in ball mill, mix dispersion obtain uniform slurry;

(3) slurry that step (2) obtains is carried out vacuum defoamation, vacuum degree is 0.07-0.09MPa, and inclined heated plate is 6-9 minute, then carries out grinding in three-high mill, rolling, reaches 4-6 micron, to obtain final product to silver slurry fineness.

Beneficial effect of the present invention

Silver slurry of the present invention, by using silver-colored bag glass dust, nickel coated copper powder, nano-sized carbon, improves electric conductivity, and has saved the consumption of silver powder, and by using silver-colored bag glass dust, wetability, the surface smoothness of slurry improve, and caking property improves; By using BTA, making metal dust not easily oxidized in high temperature working processes, keeping good conductivity, the production technology of the present invention's silver slurry is simple, can prevent silver powder from reuniting, affect conductivity; Glass dust of the present invention is not leaded, free from environmental pollution, and fusing point is low, and caking property is good.

Embodiment

A kind of printed circuit board (PCB) silver slurry of low silver content, is made up of the raw material of following weight portion (kilogram): 1-10 μm of silver powder 45, silver-colored bag glass dust 18, nickel coated copper powder 3, BTA 1.5, glass dust 7, nano-sized carbon 2, ethyl cellulose 8, butyl carbitol acetate 8, PVP 1.5, diisobutyl phthalate 1.5, ethanol 5, castor oil 4, isobutanol 7;

Described glass dust is made up of the raw material of following weight portion (kilogram): borax 16, Si0 ₂7, Bi ₂0 ₃23, A1 ₂0 ₃6, Li ₂04, MgO 5, NaF 3, Ti0 ₂4, ZnO 6, K ₂o 1.5, anoxic cerium oxide 1.5, nepheline powder 3, nanometer jade powder 3; Preparation method is: by borax, Si0 ₂, Bi20 ₃, A1 ₂0 ₃, Li ₂0, MgO, NaF, Ti0 ₂, ZnO, K ₂o, anoxic cerium oxide mix, put into crucible and become liquid 1200 DEG C of heat fused, vacuum defoamation is carried out after stirring, vacuum degree is 0.13MPa, and inclined heated plate is 7 minutes, then pours in mould and shape, carry out shrend again, send into pulverizing in ball mill, sieve, obtain 3 μm of powder, then mix with nepheline powder, nanometer jade powder, to obtain final product.

The preparation method of the printed circuit board (PCB) silver slurry of described low silver content, comprises the following steps:

(1) by butyl carbitol acetate, diisobutyl phthalate, castor oil, isobutanol mixing, add ethyl cellulose, be heated to 78 DEG C, be stirred to resin and all dissolve, filter with 500 object gauzes, removing impurity obtains organic carrier;

(2) ethanol is mixed with PVP, BTA, nano-sized carbon is added under stirring at 6000 revs/min, stir 15 minutes, mix with 6 μm of silver powder, silver-colored bag glass dust, nickel coated copper powder again, stir 15 minutes, add in organic carrier together with other residual componentss again, in ball mill, mix dispersion obtain uniform slurry;

(3) slurry that step (2) obtains is carried out vacuum defoamation, vacuum degree is 0.08MPa, and inclined heated plate is 7 minutes, then carries out grinding in three-high mill, rolling, reaches 5 microns, to obtain final product to silver slurry fineness.

Test data:

The mode of the silver slurry silk screen printing obtained by the present embodiment is printed onto in PCB, solidifies and forms conducting wire in 6 minutes, thus obtain conducting wire plate at being then warming up to 630 DEG C.The wiring width recording conducting wire is 0.6mm, average film thickness 4 μm, and wire distribution distance is 0.7mm, and resistivity is 4.9 × 10 ^-5Ω m.

Produce conducting wire plate 1000 pieces in batches in the manner described above, conducting wire is combined with PCB well, svelteness, continuously, has the conducting wire of 2 pieces of circuit boards to come off from stock, rate of finished products 99.8%.

Claims (2)

1. the printed circuit board (PCB) silver slurry of a low silver content, is characterized in that being made up of the raw material of following weight portion: 1-10 μm of silver powder 40-50, silver-colored bag glass dust 15-20, nickel coated copper powder 2-4, BTA 1-2, glass dust 6-8, nano-sized carbon 1-3, ethyl cellulose 7-10, butyl carbitol acetate 7-9, PVP 1-2, diisobutyl phthalate 1-2, ethanol 4-6, castor oil 3-5, isobutanol 5-8;

Described glass dust is made up of the raw material of following weight portion: borax 15-17, Si0 ₂6-9, Bi ₂0 ₃20-25, A1 ₂0 ₃5-8, Li ₂0 3-5, MgO3-6, NaF2-4, Ti0 ₂3-6, ZnO4-7, K ₂o1-2, anoxic cerium oxide 1-2, nepheline powder 2-4, nanometer jade powder 2-5; Preparation method is: by borax, Si0 ₂, Bi20 ₃, A1 ₂0 ₃, Li ₂0, MgO, NaF, Ti0 ₂, ZnO, K ₂o, anoxic cerium oxide mix, put into crucible and become liquid 1100-1400 DEG C of heat fused, vacuum defoamation is carried out after stirring, vacuum degree is 0.10-0.14MPa, and inclined heated plate is 6-9 minute, then pours in mould and shape, carry out shrend again, send into pulverizing in ball mill, sieve, obtain 2-6 μm of powder, then mix with nepheline powder, nanometer jade powder, to obtain final product.

2. the preparation method of the printed circuit board (PCB) silver slurry of low silver content according to claim 1, is characterized in that comprising the following steps:

(1) by butyl carbitol acetate, diisobutyl phthalate, castor oil, isobutanol mixing, add ethyl cellulose, be heated to 75-80 DEG C, be stirred to resin and all dissolve, filter with 500 object gauzes, removing impurity obtains organic carrier;

(2) ethanol is mixed with PVP, BTA, nano-sized carbon is added under stirring at 5000-7000 rev/min, stir 10-20 minute, mix with 1-10 μm of silver powder, silver-colored bag glass dust, nickel coated copper powder again, stir 10-20 minute, add in organic carrier together with other residual componentss again, in ball mill, mix dispersion obtain uniform slurry;

(3) slurry that step (2) obtains is carried out vacuum defoamation, vacuum degree is 0.07-0.09MPa, and inclined heated plate is 6-9 minute, then carries out grinding in three-high mill, rolling, reaches 4-6 micron, to obtain final product to silver slurry fineness.