【摘要】：隨著電子行業(yè)無鉛化進(jìn)程的推進(jìn),Sn-Ag-Cu系無鉛釬料以其良好的潤濕性、力學(xué)性能和可靠性成為Sn-Pb釬料最具潛力的替代合金。與此同時(shí),Sn-Ag-Cu系無鉛釬料熔點(diǎn)較高,等溫時(shí)效時(shí)釬料中Cu6Sn5粗化等問題亟待解決。另外,金屬Ag價(jià)格高,也是制約Sn-Ag-Cu釬料普及的主要原因之一。因此,對于低銀Sn-Ag-Cu釬料及其微合金化對其組織和性能的研究具有重要意義。本文首先對不同Ag含量的Sn-Ag-Cu合金(Sn-3.0Ag-0.5Cu、Sn-1.0Ag-0.5Cu、Sn-0.3Ag-0.7Cu和Sn-0.7Cu)的力學(xué)性能性能與顯微組織進(jìn)行系統(tǒng)的比較,討論采用低銀Sn-1.0Ag-0.5Cu釬料替代高銀釬料的可行性。其次,在低銀Sn-1.0Ag-0.5Cu無鉛釬料的基礎(chǔ)上添加少量金屬元素In(1.0%-4.0%),研究其對釬料合金顯微組織、熔化溫度、潤濕性能、界面金屬間化合物(IMC)的生長以及焊點(diǎn)可靠性的影響,重點(diǎn)討論了焊點(diǎn)在等溫時(shí)效過程中抗拉強(qiáng)度和抗剪強(qiáng)度的變化。研究結(jié)果表明,隨著Sn-Ag-Cu釬料中Ag含量的增加,Sn-Ag-Cu合金的潤濕性能得到提升,基體中網(wǎng)狀共晶相增加,Sn-AgCu/Cu界面IMC的尺寸逐漸減小,但Sn-1.0Ag-0.5Cu釬料與高銀Sn-3.0Ag-0.5Cu釬料的現(xiàn)象相差不大。等溫時(shí)效的過程中,BGA焊點(diǎn)的剪切強(qiáng)度先下降后趨于穩(wěn)定,150℃時(shí)效960h后,Sn-1.0Ag-0.5Cu和Sn-3.0Ag-0.5Cu的剪切強(qiáng)度相差3MPa左右。以上結(jié)果可以說明,在高溫服役足夠長的時(shí)間后,Sn-1.0Ag-0.5Cu合金完全可以取代高銀SnAg-Cu合金的使用。添加In元素后,Sn-1.0Ag-0.5Cu-x In合金的熔點(diǎn)隨著In含量的增加而逐漸降低。當(dāng)In的添加量為4.0%時(shí),其合金的鋪展面積最大,但釬料的抗氧化性能逐漸下降。In的添加,細(xì)化了Sn-1.0Ag-0.5Cu釬料合金的組織。當(dāng)In的添加量超過2.0%時(shí),Sn-1.0Ag-0.5Cu-x In合金在高溫時(shí)效后基體中出現(xiàn)大量的塊狀I(lǐng)MC�；亓骱蟮腂GA焊點(diǎn)中Sn-1.0Ag-0.5Cu-x In/Cu界面IMC的形貌與厚度變化不大,In參與了界面金屬間化合物的形成,IMC成分為Cu6(Sn,In)5。在等溫時(shí)效的過程中,IMC的厚度逐漸增加,In的添加抑制了界面IMC的生長,阻礙了Cu6(Sn,In)5向Cu3(Sn,In)轉(zhuǎn)變。其中,當(dāng)In的添加量為2.0%時(shí),對界面IMC生長的抑制作用最為明顯。力學(xué)性能方面,隨著In含量的增加,Sn-1.0Ag-0.5Cu-xIn合金的抗拉強(qiáng)度和剪切強(qiáng)度逐漸升高。時(shí)效過程中,合金的力學(xué)性能逐漸下降并最終趨于穩(wěn)定。時(shí)效960h后,Sn-1.0Ag-0.5Cu-2.0In的抗拉強(qiáng)度和剪切強(qiáng)度最高。結(jié)合成本原因,綜合考慮得出In的添加量不宜超過2.0%。
[Abstract]:With the development of lead-free process in electronic industry, Sn-Ag-Cu system lead-free solders have become the most promising substitute alloys for Sn-Pb solders because of their good wettability, mechanical properties and reliability. At the same time, the melting point of Sn-Ag-Cu lead-free solder is high, and the Cu6Sn5 coarsening in the solder during isothermal aging is urgent to be solved. In addition, the high price of metal Ag is also one of the main factors restricting the popularity of Sn-Ag-Cu solders. Therefore, it is of great significance to study the microstructure and properties of low silver Sn-Ag-Cu solders and their microalloying. In this paper, the mechanical properties and microstructure of Sn-Ag-Cu alloys with different Ag content (Sn-3.0 Ag-0.5CuN Sn-1.0 Ag-0.5CuSn-0.3Ag-0.7Cu and Sn-0.7Cu) were systematically compared. The feasibility of using low-silver Sn-1.0Ag-0.5Cu filler metal to replace high-silver filler metal was discussed. Secondly, on the basis of low silver Sn-1.0Ag-0.5Cu lead-free solder, a small amount of metal element in (1.0-4.0%) was added to study the effect of the filler metal on microstructure, melting temperature, wettability, growth of intermetallic compound (IMC) and reliability of solder joint. The variation of tensile strength and shear strength of solder joints during isothermal aging was discussed. The results show that with the increase of Ag content in Sn-Ag-Cu solder, the wettability of Sn-Ag-Cu alloy is improved, and the size of IMC at the interface of Sn-AgCu / Cu decreases with the increase of netlike eutectic phase in the matrix, but the phenomenon of Sn-1.0Ag-0.5Cu solder is not different from that of high silver Sn-3.0Ag-0.5Cu solder. During isothermal aging, the shear strength of Sn-1.0Ag-0.5Cu and Sn-3.0Ag-0.5Cu decreases first and then tends to stabilize at 150 鈩，

本文編號：2142580