TW200817126A - Electronic connecting materials for the Sn-Zn-Ag system lead-free solder alloys - Google Patents

Abstract

This patent deals with a lead-free solder alloys for four elements and five elements including as follows:1. 7-10 wt% Zn, 0-1.0 wt% Ag, 5-9.8 wt% Bi and the balance of alloys being substantially Sn.2. 7-10 wt% Zn, 0-1.0 wt% Ag, 0.5-8.0 wt% In and the balance of alloys being substantially Sn.3. 7-10 wt% Zn, 0-1.0 wt% Ag, 0-0.3 wt% Al, 5-22 wt% Bi and the balance of alloys being substantially Sn.4. 7-10 wt% Zn, 0-1.0 wt% Ag, 0-0.3 wt% Al, 0.5-8 wt% In and the balance of alloys being substantially Sn. The present invention has made it possible to provide a lead-free solder alloy has a melting point lower than 200 DEG C, which is close to 183.5 DEG C of the eutectic Sn-Pb alloy.

Description

200817126 IX. Description of the invention: [Technical field to which the invention pertains] The invention relates to an electronic connection material which is a non-error solder alloy, a S-Zn, a quaternary and a five-element error-free solder alloy. Its melting point is lower than 200X, and is close to the melting point of lead-tin eutectic alloy 183. ^ [Prior Art] The main component of typical solder alloy materials is lead-tin alloy. Lead is harmful to the human body and can cause environmental pollution. Therefore, it is urgent to develop lead-free solder materials. The tensile strength of tin-silver eutectic alloy is higher than that of traditional 钖σ gold, but its melting point is too south, about 22i °c, and the melting point of the wrong-tin eutectic alloy (at 35 °C) is higher. Many, it is easy to cause the equipment to be replaced and the related process cost is increased, and the electronic components will be damaged due to high temperature during the welding work. Although many patent documents attempt to use tin-silver eutectic alloys as the main ternary, ternary and pentad alloy systems, a small amount of other alloying constituents such as Cu, Zn, Bi, and yttrium are added to reduce tin-silver eutectic. The melting point of the alloy, but some of its melting point is still at 200 ° C. Although the addition of a large number of twists and ins can lower the melting point of the alloy, the cost is greatly increased, for example, Sn-Ag-Cu, USP 5,527,629 (1996); Sn-Ag-Zn-Bi, USP 5,993,736 (1999);

Sn-Ag-Bi-In, USP 5,958,333 (1999), USP 5,843,371 (1998), USP 5,658,528 (1997);

Sn-Ag-Bi-Cu-In, USP 5,918,795 (1999); Sn-Ag-In-Bi-Sb, USP 5,733,501 (1998); _Sn-AgHBi'USP5;?62,866^8). Therefore, the present invention will be based on tin-zinc-silver-based alloys, adding elements such as ing, yttrium or indium, taking the primary wetting properties and cost of welding as considerations, and obtaining the Sn-Zn of the present invention at an appropriate weight percentage. a quaternary lead-free solder alloy of Ag-Bi and S~Zn-Ag-In and a five-element lead-free solder alloy of Sn-Zn-Ag4Bi and Sn-Zn-Ag-A14n. SUMMARY OF THE INVENTION An object of the present invention is to provide a lead-free bismuth-zinc-based solder alloy which has the advantages of replacing the conventional lead-tin eutectic alloy and having better wetting properties, such as time and difficulty; Low; and lower than the melting point of fine T, even lower than the melting point of lead-tin eutectic alloy (183 5 〇, without causing damage to redundant components. Another object of the present invention is to provide a lead-free Tin-zinc-based solder alloy having high wetting ability. For the purpose of the present invention as set forth in 200817126, the present invention provides a lead-free solder alloy comprising the following composition - 740 wt% Zn (zinc)' ( M.〇w%Ag (silver), 8 wt% Bi (8), the rest fine (tin). 2, 7-10 wt% Zii (zinc), (iv) wt% Ag (silver), 〇·5·_%Ιη ( Indium), the rest is as (tin). Third, 740wt% Zn (zinc), (M wt% Ag (silver), 0-0.3 wt% A1 (Ming), 5_22 Bi (Sui), the rest of the composition is Sn (tin) 4, 7-10 wt% 锌 (zinc), (MO wt% Ag (silver), 0-0.3 wt% A1 (inscription), 〇-8 in % In (copper), the rest in Sn (tin). - we discover The addition of Bi and 1 elements not only reduces the melting point of Sn-Zn-Ag and Sn-Zn-Ag-Al alloys, but also improves the wetting properties of the alloy. The solid solubility of Sn in the Sn is 4_5wt% (5(TC), exceeding Bi other than the solid solubility limit, mainly precipitates - forms a chest ch in the base, and forms an InSn compound, Ag and a compound forming AgZn3AAg5Zns in the _Sn base. The present invention provides a lead-free tin-zinc-silver-based solder alloy. In terms of melting point temperature, compared with alloys such as tin-zinc eutectic and tin-zinc eutectic, it is closer to lead-bismuth eutectic alloy (183 5T), as shown in Table 丨 and Table 2. Among them, 8~8 % M% Zn-0.5 wei Ag-xAM0wt% Bi (x = 0, 〇. 〇 _ and aiwt%), which is closest to the melting point of the stigmatized eutectic alloy. As the content of bismuth (Bi) increases, the melting temperature of the alloy is lower. On the contrary, the higher the melting point temperature of the alloy. In addition, 'Sn-8.55 wt% Zn-0.5 wt% Ag-xAI-7.5 wt% In (X = 〇, 〇. (Η, 〇·〇5 and 〇.1 swim 0), closest to the melting point of the staggered eutectic alloy, as the content of indium (In) decreases, the melting point temperature of the alloy is higher. In terms of wetting force and wetting time, the present invention uses the wetting balance gamma results as 1 to FIG. 4 .Sn-8.55 Li ring shown Zn-0.5 billion Ag-7.5wt% Bi, Sn-8.55wt% Ζη-0 · 5 Ag-OJ de pain de A1

Sn-8.55wt% Zn-0.5鸠Ag catches -7·5 sides In (X = 〇, 〇·〇卜〇·〇5 and 〇lwt riding quality - 濶 wet time and wetting force can be eutectic with lead tin The turbidity and wettability of the alloy is comparable. The invention _ zinc-silver-based alloy does not contain the recorded lead, does not cause environmental gambling, and its melting point is lower than 200 C ' even lower than the melting point of the staggered tin eutectic alloy, It can solve the problem of excessive temperature of tin-silver eutectic, tin-copper eutectic and tin-silver-copper lead-free solder alloy, and will not damage κ electronic components during electronic assembly. At the same time, it can also solve yttrium indium eutectic. The temperature of the tin-free eutectic lead-free solder alloy is too low, and the electronic product is not suitable for the work of the cabinet. In terms of cost, the present invention reduces the content of the (four) and indium (10) in the US C coffee. The conditions recommended by Sciences), the content of bismuth (four) should be lower than that of view, the content of indium (10) 6 200817126 should be lower than l·5% 'far less than the inclusion of tin indium eutectic and tin-bismuth eutectic alloy 58 The inclusion of % and indium (10) to 52% is mainly to reduce the soldering characteristics of the electronic package of the alloy. the amount. In the tin-zinc-silver-based solder 钖 alloy of the present invention, silver (Bi) and indium are added (Kun element, melting point temperature (the melting point of Bi is 271.3T and the melting point of to is 156|6. 〇, further improvement 200817126 Table 1·

Alloy composition (wt%) Sn Zn Ag A1 Bi Solidus temperature (°C) Liquidus temperature (.〇Bal. 8.55 0.5 One 198.3 199.8 BaL 8.55 0.5 0.01 ---- 198.51 199.37 Bal 8.55 0.5 0.05 -- -- 198.49 199.39 Bal 8.55 0.5 0.1 one 198.51 201.97 Bal 8.55 0.5 - one 7.5 184.46 190.76 Bal 8.55 0.5 — 10 181.4 188.3 Bal. 8.55 0.5 One 15 176 184.6 Bal. 8.55 0.5 — 20 165.5 178.5 Bal. 8.55 0.5 0.01 7.5 187.3 191.9 Bal. 8.55 ;0.5 0.01 10 181.8 189.1 Bal. 8.55 0.5 0.01 15 173.7 184.5 Bal. 8.55 0.5 0.01 20 165.7 178.2 Bal. 8.55 0.5 0.05 7.5 186.5 191.6 Bal 8.55 0.5 005 10 181.9 189 Bal. 8.55 0.5 0.05 15 173.8 184.3 BaL 8.55 0.5 0.05 20 165.6 178.4 Bal. 8.55 0.5 0.1 7.5 186.6 191.2 Bal 8.55 0:5 0.1 10 182 188.8 Bal 8.55 0,5 0.1 15 173.8 183.7 Bal. 8.55 0.5 0.1 20 165.4 178.2 Bal. 9 One--- •~ _ 198.4 200.8 63Sn_37Pb 183.50 185.42 200817126 Table 2·

Alloy composition (wt%) Sn Zn Ag A1 In Solidus temperature (°C) Liquidus temperature (.〇Bal. 8.55 0.5 — 198.3 199.8 Bal. 8.55 0.5 0.01 —- 198.51 199.37 Bal. 8.55 0.5 0.05 --- - 198.49 19939 Bal. 8.55 0.5 0.1 ~- a 198.51 201.97 Bal. 8.55 0.5 —— 1 191.9 200.1 Bal· 8.55 0.5 3 192.3 197.1 Bal. 8.55 0.5 One to five 187.3 191.4 BaL 8.55 0.5 One 7.5 182.3 188.3 Bal. 8.55 0.5 0.01 1 191.9 197.1 BaL 8.55 0.5 0.01 3 192.3 194.4 Bal. 8.55 0.5 0.01 5 190 191.6 Bal. 8.55 0.5 0.01 7.5 185.5 188.5 Bal. 8.55 0.5 0.05 1 195.2 197.4 Bal. 8.55 0.5 0.05 3 192.2 194.3 Bal. 8.55 0.5 0.05 5 189.5 191.6 Bal. 8.55 0.5 0.05 7.5 185.5 188.6 Bal. 8.55 0.5 0.1 1 195.1 1973 Bal 8.55 0.5 0.1 3 191.4 194 Bal. 8.55 0.5 0.1 5 189.2 191.6 Bal· 8.55 0.5 0.1 7.5 184.7 188.3 BaL 9 I— ---- I. 198.4 200.8 63Sn-37Pb 183.50 185.42 9 200817126 [Embodiment] Comparative example

The Sn-Zn eutectic alloy is prepared by mixing a pure metal material of Sn and Zn with a purity of 99.99%, mixing in a weight percentage of bismuth zinc eutectic, placing it in a high temperature heating furnace, heating to 700 ° C, and holding the temperature for 3 hours. The material composition is homogenized, and the Sn-9 wt% Zn eutectic alloy is synthesized. Then take Sn-9wt% Zn eutectic alloy, the weight is i〇mg, using thermal difference

Differential Scanning Calorimeter (DSC) was used to measure the solid phase of the Sn-Zn eutectic alloy at 1984 °C and the liquidus point at 200.8 °C. The copper wire with a diameter of 1mm was used as the substrate, and the purity was 99.9%. It was immersed in 7〇〇c^5wt% sodium oxynitride (NaOH) lye before the wetting experiment, and after removing the grease for five minutes, it went Ion water cleaning. Then, it was placed in a nitric acid (HN〇3) solution of 1 〇City 0/〇, and after removing the oxide for 5 seconds, it was washed with deionized water. Finally, it was washed with 98% pure alcohol for five seconds and then dried. After the above pretreatment, the steel wire substrate is placed in the flux for 30 seconds, and then dried at 60T for 20 seconds, and then wet balance test, immersion plating on 25 (rc Sn_Zn eutectic alloy) Solution: The wetting property between the Sn-Zn eutectic alloy and the copper wire substrate was found, the maximum wetting force was 〇41 mN and the wetting time was 1.33 seconds.

The preparation and test methods of the Sn-8.55% Zn-0.5% Ag-7.5% Bi alloy were the same as those of the comparative example. From the wetting balance results, the average maximum wetting force was 〇94 mN. The average wetting time was 〇64 seconds. Compared with the Sn_9Zn eutectic solder, the wetting force (~0·41ιηΝ) of the tin alloy is about twice, and the wetting time (~1.32 seconds) is superior. It is closer to the wetting force (U66Nm) of 63Sn_37Pb and the wetting time (0.47 seconds). Example 2

The preparation and test methods of Sn_8i55%Zn-0, 5%Ag-0.1%AM0%Bi alloy were the same as those of the comparative example. According to the wetting balance, the average maximum wetting force is 14 and closer to 63Sn-37Pb (1.166 Nm). The average wetting time is 0.59 seconds, which is closer to 63Sn-37Pb (0.47 seconds). The average maximum wetting force and average wetting time are superior to those of the Sn-9Zti eutectic solder alloy. The melting point of Sn_8.55%Zn-0.5%Ag-0.1%Al-10%Bi alloy (solid phase line is 182 °C 'liquidus line is 188.8 °C), close to the melting point of 63 Sn-37 Pb alloy The solidus line is i83.5 ° C, the liquidus is 185·4 ° 〇. At the same time, it is lower than the melting point of Sn-9Zn eutectic solder alloy (solid phase line is 198.4 ° C, liquidus is 200.8 °) C). 200817126 Example 3

The preparation and test methods of the Sn-8.55% Zn-0.5% Ag-7.5% In alloy were the same as those of the comparative example. From the results of the wetting balance, the average maximum wetting force was 0.94 mN, and the average wetting time was 〇·54 seconds. It is close to 63Sn-37Pb maximum wettability (U66Nm) and wetting time (0.47 seconds). The melting point of the alloy (solid phase line is 18Z3 ° C, liquidus is 188.3 〇C), close to the melting point of 63 Sn-37Pb alloy (solid phase line is 183.5 〇C, liquidus is 185.40 C) 实施 Example 4

The preparation and test methods of Sn-&55%Zn-0.5%Ag-0.01%Al-7.5%In alloy were the same as those of the comparative example. From the results of the wetting equilibrium, the average maximum wetting force was 1 17 mN and the average wetting time was 0.55 seconds. Close to 63Sn-37Pb maximum wetting force and wetting time. The melting point of the alloy (solid phase line is 185, liquidus is 188.5. 〇, close to the solidus and liquidus of the 63 Sn-37Pb alloy. Example 5

The preparation and test methods of Sn_8j5%Zn_a5%Ag-0.05%Al-T5%In alloy were the same as those of the comparative example. From the wetting equilibrium results, the average maximum wetting force was 1.345 mN and the average wetting time was 〇.55 seconds. Close to 63Sn-37Pb maximum wetting force and wetting time. The melting point of the alloy (solid phase line is 185 5 €, liquidus line is 188 6 ° C), which is close to the solidus and liquidus of the 63 Sn-37Pb alloy. Example 6. The preparation and test methods of 8'55/°Zn 〇 5/eAg-01%AiJ7 '5%In alloy were the same as those of the comparative example. By wetting φ balance... it is known that its average maximum wetting force is U6mN and the average wetting time is 0,58 seconds. Close to 6 Shi-3 punishment Maximum wetting force and dampness time. The melting point of the alloy _ line is 184r>c, and the liquidus is expanded. c), close to the solidus and liquidus of the 63 Sn-37Pb alloy. 11 200817126 BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a graph showing the wetting force relationship of a Sn{55ZiM).5Ag-xAl-yBi solder alloy and a 63Sn-37Pb solder alloy of the present invention. Wherein square () is 〇 weight %..., circle (*) is 0. 01% by weight A1, diamond (♦) is 〇〇5 weight 4% A1 ' and triangle (▲) is 0.1% by weight A1. Fig. 2 is a graph showing the wetting time of the sn-8.55Zn-0.5Ag-xAl-yBi solder alloy and the 63Sn-37Pb solder alloy of the present invention. Wherein square () is 〇% by weight, round (repair) is 0.01% by weight of A1, diamond is 〇() 5% by weight of A1, and triangle (?) is 0.1% by weight of A1.

Fig. 3 is a graph showing the wetting force relationship of the 8η-8·55Ζη·0·5Α§-χΑΐ5ΐη solder alloy and the 63Sn-37Pb solder alloy of the present invention. Wherein square () is 〇 weight %^1, circle (♦) is 0.01% by weight of A1, diamond (♦) is 〇05 by weight% A1, and triangle (▲) is 0.1% by weight of A1. Fig. 4 is a graph showing the wetting force of the Sn-g.55Zn-0.5Ag-xAl-yIn soldered aluminum alloy and the 63Sn-37Pb soldered aluminum alloy according to the present invention. Wherein square () is 0% by weight of A1, round (_) is 0.01% by weight, A diamond is 〇〇5 weight, i% Al, and triangle (▲) is 〇·1% by weight A1. 12

Claims (1)

200817126 X. Patent application scope: 1. A lead-free solder, which is composed of 7.0-10.0% by weight of zinc (Zn), 04.0% by weight of silver (Ag), 5,0-9.8% by weight of bismuth (Bi) and the rest Tin (Sn) composition. 2. The soldering iron of claim 1, further comprising 7.5-9.0% by weight of bismuth (Bi). 3. A lead-free solder comprising 7.0-10.0% by weight of zinc (Zn), 04.0% by weight of silver (Ag), 0-0.3% by weight of aluminum ("), 5.0-22.0% by weight of bismuth (Bi) and The remainder is composed of tin (Sn). 4. The solder of claim 3, further comprising 7.5-10.0% by weight of bismuth (Bi). 5. The solder of claim 3, further comprising Ο.οι-αι% by weight of aluminum (A1). 6. A modified lead-free solder comprising 7.040.0% by weight of zinc (Mn), 04.0% by weight of silver (Ag), and the balance being tin (Sn), characterized in that the solder further comprises 0-8.0 by weight % indium (In). 7. The solder of claim 6, which comprises 1.0 to 7.5% by weight of indium (In). 8. A modified lead-free solder comprising 7.040.0% by weight of zinc (Ζιι), 0-1.0% by weight of silver (Ag), 0-0.3% by weight of aluminum ("), 0-8.0% by weight of indium (In) and the remainder being composed of 钖 (Sn) 9. The solder of claim 8 contains 1.0-7.5 wt% of indium (In). 10. As claimed in claim 8 of the solder, It contains 0.01 to 0.1% by weight of aluminum (A1). 13