CN1053516C - Slurry for silver leads of surface installed multi-layer disc ceramic capacitor - Google Patents

Abstract

The present invention relates to a slurry material pasting on the surface of a full silver pasting end head of a multilayer ceramic dielectric capacitor of a sheet type, which comprises silver powder, a glass material and an organic vehicle. In the slurry material, ZnO-Al2O3-B2O3-SiO2 glass powder is adopted as an inorganic filler, and rosin resin, ethyl cellulose, terpineol and butyl carbitol are adopted as organic vehicles. The prepared slurry material is uniform, fine and smooth, and after the slurry material is burned and leaked, the slurry material has smooth appearance and good current conducting performance. After the slurry material is electroplated under an acidic condition, the slurry material does not generate extending or bridging phenomena, but has high adhesion force and satisfies the technique requirements of a production-line.

Description

Surface mount can be plated the termination slurry with the full silver of chip multilayer ceramic capacitor

The present invention relates to the full silver of chip multilayer ceramic capacitor and can plate the termination slurry.

At present in the chip multilayer ceramic capacitor structure, general wire type and the flatiron manual welding type of adopting, but such capacitor outer electrode adopts full silver bonding tip slurry, its anti-sweating heat 260 degree, dip time is lower than 5 seconds, development along with surface mounting technology, the automatic chip mounting capacitor must withstand wave-soldering technology or infrared reflow welder preface efficiently, in this course, chip component wants the long period directly to immerse in the rodent high-temperature solder, and traditional full silver or palladium-silver capacitor termination are difficult to bear this abominable operation.The three layers of electroplating technology in the nickel barrier layer of employing are arranged, i.e. electroless nickel layer and tin layer (or leypewter layer) on silver-colored termination, this technology improves the anti-sweating heat performance of chip capacitor greatly, can be in 260 degree scolders, dip time surpasses 1 minute, as seen, and the use of three layers of electroplating technology, make chip capacitor termination electrode must stand this severe rugged environment of acidic bath, this opposite end tip electrode slurry has proposed new requirement.

The objective of the invention is at above-mentioned deficiency, propose a kind of surface mount and can plate the termination slurry with the full silver of chip multilayer ceramic capacitor, its slurry is even, fine and smooth, outward appearance light after the burning infiltration, electric conductivity are good, behind acid electroplating, do not produce and extend the bridge joint phenomenon, have higher adhesive force, satisfy the production-line technique requirement.

The present invention is made up of following (weight ratio),

Silver powder 65～83 (wt) %, wherein spherical silver powder and flake silver powder ratio are 1: 0.3～1.5;

Frit 2～25 (wt) %, wherein frit consists of:

PbO 40～60(Wt)％

B ₂O ₃ 5～15(Wt)％

SiO ₂ 25～40(Wt)％；

Additive 10～25 (Wt) %, it is by Al ₂O ₃, CaO, CdO, CuO,

Li ₂O, Na ₂O, NiO, WO ₃, TiO, Zn one or more

Mixture is formed;

Organic carrier 10～25 (Wt) %, rosin phenolic resin 20～35 (wt) % wherein,

Ethyl cellulose 1～3 (wt) %,

Terpinol 50～55 (wt) %,

Castor oil 5～12 (wt) %,

Thixotropic agent 1～2 (wt) %,

Defoamer 0.05～2 (wt) %.

Optimum formula (weight ratio) is formed, silver powder 75～79 (wt) %,

Frit 2～5 (wt) %,

Organic carrier 19～24 (wt) %.

We can be from termination electrodes specification of a model the present invention, accompanying drawing 1, accompanying drawing 2, before accompanying drawing 3 is termination electrodes model burning infiltration respectively, after, electroplate back three kinds of states, Fig. 1 is that complete silver-colored platable end paste is coated on formed conductive pattern after the drying of ceramic matrix surface, the 1st, ceramic matrix, the 2nd, the termination slurry, silver powder and the inorganic filler state that is evenly distributed in the conductive layer, the conductive layer interface is attached on the coarse ceramic matrix, Fig. 2 is the monolithic capacitor termination section after the burning infiltration, the 3rd, the continuous metal conductor, the 4th, the low-melting-point glass bonded areas is enriched in the glass melt on conductive layer and ceramic matrix surface, forms a discrete firm bonded areas after cooling, has the favorable mechanical bonding force, Fig. 3 is the termination section of the monolithic capacitor after electroplating, the 5th, and tin layer, the 6th, nickel dam, the 7th, silver layer, after the plating, be coated with last layer thermal barrier properties nickel dam on the fine and close silver layer, and the tin layer of plating one deck good weldability becomes tin lead layer on nickel dam.

The present invention compares with the U.S., Japanese similar slurry measured data, sees Table 1.

Now from above-mentioned prescription, before enumerating five embodiment plating being described, plating back electrical property with and adhesive force.

Table 1

Item item claim	Complete silver-colored platable end paste	U.S. MIS company's T-2038	The clear flourish H-2955 of company of Japan
				Viscosity (Pa.s/25 ℃ of 10rpm)	45～55	40～45	50～55
Tenor (%)	75	72	75
				Drying condition (℃)	230～260 12 minutes	250～260 10 minutes	250～260 10 minutes
The burning infiltration temperature (℃)	760～800	760～780	760～780
				Side's resistance (Ω/)	0.0035	0.003	0.0027
Pulling force (Kg/mm2)	2.5	1.8	1.8
				Fineness 50%	8	10	8
Smell	Denseer cloves type	Than giving off a strong fragrance any of several broadleaf plants type	Lighter
				Electric capacity is electroplated the back outward appearance	There is not the no bridge joint of extension	There is not the no bridge joint of extension	There is not the no bridge joint of extension

Embodiment 1:

Material	Prescription	Addition (Wt%)
			Frit	45％PbO/10％B 2O 3/35％SiO 2％ZnO/ 2％Al 2O 3/5％CaO/1％CuO	4.25
Silver powder	Spherical silver powder: flake silver powder=1: 0.5	74
			Organic carrier	Rosin phenolic resin 25%, turpentine oil 10%, thixotropic agent 1.7%, ethyl cellulose 2.5%, castor oil 5%, terpinol 55%, defoamer 0.1%	21.75

Embodiment 2:

Material	Prescription	Addition (Wt%)
			Frit	43％PbO/10％B 2O 3/30％SiO 2％ZnO/ 2％WO 33％Al 2O 3/5％CaO/3％CuO 3％Na 2O/3％CdO	4.25
Silver powder	Spherical silver powder: flake silver powder=1: 0.5	74
			Organic carrier	Rosin phenolic resin 25%, turpentine oil 10%, thixotropic agent 1.7%, ethyl cellulose 2.5%, castor oil 5%, terpinol 55%, defoamer 0.1%	21.75

Embodiment 3:

Material	Prescription	Addition (Wt%)
			Frit	45％PbO/10％B 2O 3/35％SiO 2％ZnO/ 2％Al 2O 3/5％CaO/1％CuO	4.25
Silver powder	Spherical silver powder: flake silver powder=1: 1.1	74
			Organic carrier	Rosin phenolic resin 25%, turpentine oil 10%, thixotropic agent 1.7%, ethyl cellulose 2.5%, castor oil 5%, terpinol 55%, defoamer 0.1%	21.75

Embodiment 4:

Material	Prescription	Addition (Wt%)
			Frit	45％PbO/10％B 2O 3/35％SiO 2％ZnO/ 3％Al 2O 3/5％CaO/1％CuO	4.25
Silver powder	Spherical silver powder: flake silver powder=1: 0.3	74
			Organic carrier	Rosin phenolic resin 25%, turpentine oil 10%, thixotropic agent 1.7%, ethyl cellulose 2.5%, castor oil 5%, terpinol 55%, defoamer 0.1%	21.75

Embodiment 5:

Material	Prescription	Addition (Wt%)
			Frit	43％PbO/10％B 2O 3/35％SiO 2％ZnO/ 2％Al 2O 3/5％CaO/1％CuO	4.25
Silver powder	Spherical silver powder: flake silver powder=1: 0.5	74
			Organic carrier	Rosin phenolic resin 28%, turpentine oil 10%, thixotropic agent 1.9%, castor oil 5%, terpinol 55%, defoamer 0.1%	21.75

The foregoing description 1～5 result such as following table:

The slurry code	Outward appearance	Electrical property before the plating			Plating back electrical property			Adhesive force (N)
									C (nF)	DF (×10 -4)	Ri (OΩ)	C (nF)	DF (×10 -4)	Ri (OΩ)
		1	Generally	117.2	120	10	116.8								122	10	25
2	Well							115.9	122	10	115.4	125	10	28
		3	Generally	118.2	117	10	118.1								120	10	20
4	Generally							116.5	121	10	116.8	121	10	21
		5	Well	116.7	124	10	115.9								126	10	24
The contrast sample	Well							116.4	125	10	116.8	128	10	22

Claims (2)

1, a kind of surface mount can be plated the termination slurry with the full silver of chip multilayer ceramic capacitor and is made up of following (weight ratio),

Silver powder 65～83 (wt) %, wherein spherical silver powder and flake silver powder ratio are 1: 0.3～1.5;

Frit 2～25 (wt) %, wherein frit consists of:

PbO 40～60(Wt)％

B ₂O ₃ 5～15(Wt)％

SiO ₂ 25～40(Wt)％；

Additive 10～25 (Wt) %, it is by Al ₂O ₃, CaO, CdO, CuO,

Li ₂O, Na ₂O, NiO, WO ₃, TiO, Zn one or more

Mixture is formed;

Organic carrier 10～25 (Wt) %, rosin phenolic resin 20～35 (wt) % wherein,

Ethyl cellulose 1～3 (wt) %,

Terpinol 50～55 (wt) %,

Castor oil 5～12 (wt) %,

Thixotropic agent 1～2 (wt) %,

Defoamer 0.05～2 (wt) %.

2, surface mount according to claim 1 is used for chip multilayer ceramic capacitor, it is characterized in that it is made up of following (weight ratio),

Silver powder 75～79 (wt) %,

Frit 2～5 (wt) %,

Organic carrier 19～24 (wt) %.

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