High-Lead Solder Ball Characteristics in BGA Package

Author(s):  
Nicholas Kao ◽  
Y. P. Wang ◽  
C. S. Hsiao

For high performance packages in mainframe systems such as networking switch, telecommunication equipments, higher reliability is always required. Using high-lead solder ball is an effective way to enhance the solder joint performance in board level. The elongation property of high-lead alloy Sn10/Pb90 is 10 times greater than eutectic Sn/Pb alloy. The high-lead ball has higher melting temperature, it can maintain the stand off (gap) between the package and PCB when eutectic solder paste melted at 220°C. In this study, the performances of high-lead solder Sn10/Pb90 and eutectic Sn63/Pb37 are compared. A series of experiments are performed to characterize the high-lead solder ball solder joint performance. The ball shear test parameters also affect high-lead solder ball strength, such as ram height and shear speed. Lower ram height and higher speed increases the ball shear strength value. Effect of different ball pad openings, solder paste volume and reflow profile for ball placement, is also discussed in this paper. the ratio of ball pad opening diameter to solder ball diameter is related to ball shear force. When the ratio is 0.83, the ball shear is better than other value. The most important factor to ball shear strength is the solder paste amount. However, the reflow condition (the time period over 183°C) isn’t the significant factor to affect the ball shear strength.

2015 ◽  
Vol 789-790 ◽  
pp. 61-65
Author(s):  
Boon Kar Yap ◽  
Cai Hui Tan ◽  
Chou Yong Tan

Environment and the health concerns due to the hazardous effects of lead resulted in significant activities to find a replacement for lead-contained solders for electronics industrial. Majority of the semiconductor industrial are now replacing lead solders with Tin-Silver-Copper (SAC 387) solder balls. However, dropped balls in SAC 387 for Ball Grid Array (BGA) products due to poor solder joint strength caused by high thermal stress are a major concern in the semiconductor industries. Polymer core inside the solder ball (polymer core/Cu/Sn) is thus integrated to improve the solder ball joint strength. The function of polymer core inside the solder ball is to absorb and released the stress better as compared to the SAC 387 solder ball. Since the diffusion rate of Cu is faster than the diffusion rate of Sn, hence, this could caused the Kirkendall voids tends to form in between the Cu and Sn IMC layer. This would affect the solder ball joint strength and causing drop balls issue. By implement with an extra of Ni layer to the polymer core solder ball (core/Cu/Ni/Sn), could reduce the diffusion from Cu to Sn, thus to overcome the Kirkendall voids and to further improve the solder ball joint strength. This research work studies the performance of the solder ball shear strength of the two types of solder balls applied to MAPBGA device. In this research, both SAC 387 and polymer solder balls were went through under AC (Autoclave) and TC (Temperature Cycle) reliability test up to 144 hours and 1000 cycles, respectively. Solder ball shear strength test was conducted via Dage 4000 series bond tester. From the research work results of the two types of solder balls, the ball shear strength were decreased with an increased of aging and cycles. Overall, it can be concluded that the polymer core solder ball with an additional of Ni layer showed better performance than the polymer core without Ni layer and SAC 387 solder balls, after subjected to the AC and TC reliability test.


2008 ◽  
Vol 1 (1) ◽  
pp. 9-14 ◽  
Author(s):  
Ikuo Shohji ◽  
Satoshi Shimoyama ◽  
Hisao Ishikawa ◽  
Masao Kojima

Author(s):  
S. W. Ricky Lee ◽  
Yat-Kit Tsui ◽  
Xingjia Hunag ◽  
Eric C. C. Yan

This paper presents an experimental investigation on the solder ball shear strength of plastic ball grid array (PBGA) packages. The emphasis is placed on showing the effect of room temperature aging on the degradation of solder ball shear strength. The specimens under investigation are standard commercial PBGA packages with 63Sn-37Pb eutectic solder balls. The specimens are subject to various lengths (up to 72 hours) of room temperature aging after the reflow. Afterwards, ball shear tests are performed to evaluate the solder ball shear strength. The experimental results show that the solder ball shear strength may drop up to 10% within 3 days of room temperature aging. The outcome of the present study may give a general guideline for the meaningful comparison of solder ball shear strength.


Metals ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 1295
Author(s):  
Sri Harini Rajendran ◽  
Seung Jun Hwang ◽  
Jae Pil Jung

This study investigates the shear strength and aging characteristics of Sn-3.0Ag-0.5Cu (SAC 305)/Cu joints by the addition of ZrO2 nanoparticles (NPs) having two different particle size: 5–15 nm (ZrO2A) and 70–90 nm (ZrO2B). Nanocomposite pastes were fabricated by mechanically mixing ZrO2 NPs and the solder paste. ZrO2 NPs decreased the β-Sn grain size and Ag3Sn intermetallic compound (IMC) in the matrix and reduced the Cu6Sn5 IMC thickness at the interface of lap shear SAC 305/Cu joints. The effect is pronounced for ZrO2A NPs added solder joint. The solder joints were isothermally aged at 175 °C for 24, 48, 144 and 256 h. NPs decreased the diffusion coefficient from 1.74 × 10–16 m/s to 3.83 × 10–17 m/s and 4.99 × 10–17 m/s for ZrO2A and ZrO2B NPs added SAC 305/Cu joints respectively. The shear strength of the solder joints decreased with the aging time due to an increase in the thickness of interfacial IMC and coarsening of Ag3Sn in the solder. However, higher shear strength exhibited by SAC 305-ZrO2A/Cu joints was attributed to the fine Ag3Sn IMC’s dispersed in the solder matrix. Fracture analysis of SAC 305-ZrO2A/Cu joints displayed mixed solder/IMC mode upon 256 h of aging.


2005 ◽  
Vol 486-487 ◽  
pp. 269-272 ◽  
Author(s):  
Jong Woong Kim ◽  
Sun Kyu Park ◽  
Seung Boo Jung

Ball shear test was investigated in terms of the effects of important test parameter, i.e., shear height, with an experimental and non-linear finite element analysis for evaluating the solder joint integrity of area array packages. The substrate was a common SMD type with solder bond pad openings of 460 ㎛ in diameter. It was observed that increasing the shear height, at a fixed shear speed, has the effect of decreasing the shear force. The high shear height could cause some bad effects on the test results such as unexpected high standard deviation values or shear tip sliding from the solder ball surface. The low shear height conditions were favorable for screening the type of brittle interfacial fractures or the degraded layers in the interfaces.


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