CN1799761A - Lead-free solder - Google Patents

Abstract

The invention relates to a leadless solder, belonging to electric device assemblage area. It comprises following components: Ag in 10-20 deals, P in 4-6 deals and Cu in 72-86 deals, in addition, it also can add Au in 0.1-1 deals or Ni in 0.1-0.5 deals. The inventive leadless solder can avoid the harm on human body and environment, while it has better combination with welding base material, as well as better welding strength, anti-oxidation and electrical conductivity.

Description

Lead-free solder

Technical field

The present invention relates to a kind of solder alloy, particularly relate to a kind of employing and do not contain that plumbous what electronic device was assembled is the lead-free solder of base-material with copper.

Background technology

As everyone knows, tin lead (Sn-Pb) solder excellent performance is used widely in the assembling field of electronic devices and components, but making and using in the process of Sn/Pb scolder, because fusion temperature is higher, there is a large amount of lead steams to overflow, will directly have a strong impact on health of operators.In recent years, the pollution of relevant underground water lead more causes people's attention, except discarded battery is leaded in a large number, the various electronic product PCB that abandon go up contained lead and also can not be ignored, with the U.S. is example, about 100,000,000 of the annual PCB that abandons with electronic product, contain Sn/Pb scolder 10 grams by every, wherein lead content is 40% calculating, and the annual lead amount that abandons with PCB is 400 tons, when rainy, these lead become water-soluble salt, dissolve contaminant water gradually, particularly when meeting acid rain, contained in the rain nitric acid and hydrochloric acid more impel plumbous dissolving.For drinking phreatic people, along with the prolongation of time, plumbous accumulation in human body will cause lead poisoning.In addition; along with the development of minuteness space device, packing density is more and more higher, and solder joint is more and more littler; the mechanics that it carried, electricity and calorifics load are then more and more heavier; reliability requirement is improved day by day, but the creep resistance of traditional Sn/Pb alloy is poor, can not satisfies the modern age electronics industry the requirement of reliability; therefore; the development and application of lead-free solder, not only favourable to environmental protection, but also undertaking the task of improving the electronic product quality.

In recent years, the research work development of relevant lead-free solder is very fast, the last big leading company in the world, National Laboratory and institute have all dropped into the research that suitable strength is carried out lead-free solder, in the relevant patent and technology of lead-free solder, mostly be to be base-material with Sn, add Ag, Zn, Cu, Sb, Bi, metallic elements such as In, improve alloy property by solder alloyization, improve solderability, though tin has corrosion resistance preferably in atmosphere He in the tin material, do not lose metallic luster, can corrode by anti-organic acid, but the corrosion of not anti-strong acid and highly basic, and because the existence of a large amount of tin in the scolder, increased the generation of metal oxide, weld strength, the welding yield, electric conductivity all exists certain deficiency.

Summary of the invention

The technical problem to be solved in the present invention provides a kind of lead-free solder, this scolder can with the substrate good binding, have good weld strength, non-oxidizability and electric conductivity.

For solving the problems of the technologies described above, the technical solution used in the present invention is as follows:

A kind of lead-free solder, it contains following component, and the ratio of weight and number of each component is the Ag of 10-20 part, the P of 4-6 part, the Cu of 72-86 part.

As the further improvement of aforesaid way, contain the Ag of 12-18 parts by weight in the described scolder of forming by Ag, Cu, P, the P of 4.5-5.5 parts by weight, the Cu of 75-83 parts by weight.

As the further improvement of aforesaid way, contain the Ag of 15 parts by weight in the described solder alloy of forming by Ag, Cu, P, the P of 5 parts by weight, the Cu of 80 parts by weight.

As the improvement of a kind of mode of the present invention, described scolder also can further contain the Au of 0.1-1 parts by weight.

As the further improvement of aforesaid way, contain the Au of 0.5 parts by weight in the scolder of forming by Ag, Cu, P, Au.

As the improvement of another kind of mode of the present invention, described scolder is made up of Ag, Cu, P, Ni, wherein contains the Ni of 0.1-0.5 parts by weight.

As the further improvement of aforesaid way, the above-mentioned scolder of being made up of Ag, Cu, P, Ni wherein contains the Ni of 0.3 parts by weight.

The technical solution used in the present invention, because do not contain lead composition, so avoided plumbous harm to human body and environment generation, and because it is to be base-material with Cu, owing to belong to same composition with welding base metal, so play a part to improve weld strength and electric conductivity, its shared parts by weight are 72-86, the optimum weight umber is 80; The adding of Ag has been quickened in the alloy molten process to have reduced the fusing point of scolder to the welding base metal diffusion velocity, the mechanical property and the creep resistant fatigue behaviour of scolder have been improved, strengthened the electric conductivity of scolder, its shared parts by weight are 10-20, and the optimum weight umber is 15; The adding of P can suppress to combine with oxygen and the metal oxide that produces, can improve the thermal fatigue characteristics that weld part bears thermal deformation and stress, prevent thickization of crystalline particle, to reduce the possibility that the welding position produces the crack, guarantee reliable welding, its shared parts by weight are 4-6, and the optimum weight umber is 5.

In addition, also can contain the Au of 0.1-1 parts by weight in the component of scolder of the present invention, the adding of Au can further strengthen the electric conductivity of scolder.

In addition, also can contain the Ni of 0.1-0.5 parts by weight in the component of scolder of the present invention, add the Ni element, can improve the intensity of material, and improve weldability, help to solve the solder joint bridging.

Above-mentioned lead-free solder provided by the present invention, can have different profiles and form, including, but not limited to: bar, discoid, metal wire, packing ring, ribbon, spherolite, ball and other shape and powder, when preserving, adopt bottled nitrogen-sealed to preserve.

In addition, the performance of this scolder is as shown in the table:

Number/EA feeds intake	Welding											Sintering
															Weld electrical yield %	Machinery yield %	Pressure drop fraction defective % forward	Minimum	Maximum	On average	Fraction defective % reverse recovery time (≤2% is qualified)	Minimum	Maximum	On average	Pulling force/KG	Yield %	Pressure regulation fraction defective % forward	Reverse withstand voltage fraction defective %
	100	98	100	0	0.99	1.097	1.035	2	45	93	59	Greater than 8	84	0															8
50															98	100	2	0.951	1.195	1.041	0	38	64	54	82	2	12
	100	100	100	0	0.9	0.963	0.91	0	1736	2795	2370		Greater than 8	84														0	16
50												100			100	0	0.9	0.989	0.912	0	1797	2728	2344	86	0	12

Condition	Quantity	The result	Remarks
				150 degree/600W * 24H	50EA	By
150 degree/480V * 1H	50EA	By
				Standard I F from 50A test 8.3ms once	11EA	By	There is the 2EA 90A that lost efficacy/measure to have 1EA to lose efficacy when measuring 120A
Standard I F from 50A test 8.3ms once	11EA	By	There is the 1EA 85A that lost efficacy/measure to have 1EA to lose efficacy when measuring 105A

By the performance test data of this scolder as can be known, the electrical yield of the welding of this scolder, pulling force etc. all with big line weld tabs indifference, and as can be known according to the effect of above each component, this lead-free solder has good weld strength, and because it has adopted the metallic element of the more stable and easy conductive of character, so this scolder has good non-oxidizability and electric conductivity.

The present invention is further detailed explanation below in conjunction with specific embodiment.

The specific embodiment

Embodiment	The each component ratio of weight and number
						Cu	Ag	P	Au	Ni
	Embodiment 1	84.5	10	5.5

Embodiment	Each composition weight umber ratio
						Cu	Ag	P	Au	Ni
	Embodiment 2	80	15	5
Embodiment 3						76	20	4
	Embodiment 4	86	10	4.3	0.1
Embodiment 5						79	16	5.1	1
	Embodiment 6	72	20	5	0.5
Embodiment 7						82	12	6		0.1
	Embodiment 8	83	13	4.5							0.3
Embodiment 9						75	19	4.1		0.5

Claims (7)

1, a kind of lead-free solder is characterized in that: it contains following component, and the ratio of weight and number of each component is the Ag of 10-20 part, the P of 4-6 part, the Cu of 72-86 part.

2, lead-free solder according to claim 1 is characterized in that: the ratio of weight and number of this scolder each component is the Ag of 12-18 part, the P of 4.5-5.5 part, the Cu of 75-83 part.

3, lead-free solder according to claim 2 is characterized in that: the ratio of weight and number of each component is 15 parts Ag, 5 parts P, 80 parts Cu.

4, lead-free solder according to claim 1 is characterized in that: this scolder contains the Au of 0.1-1 parts by weight.

5, lead-free solder according to claim 4 is characterized in that: the Au that wherein contains 0.5 parts by weight.

6, lead-free solder according to claim 1 is characterized in that: this scolder contains the Ni of 0.1-0.5 parts by weight.

7, lead-free solder according to claim 6 is characterized in that: the Ni that wherein contains 0.3 parts by weight.