Technical Library | 2023-01-17 17:27:13.0
Reflow profile has significant impact on solder joint performance because it influences wetting and microstructure of the solder joint. The degree of wetting, the microstructure (in particular the intermetallic layer), and the inherent strength of the solder all factor into the reliability of the solder joint. This paper presents experimental results on the effect of reflow profile on both 63%Sn 37%Pb (SnPb) and 96.5%Sn 3.0%Ag 0.5%Cu (SAC 305) solder joint shear force. Specifically, the effect of the reflow peak temperature and time above solder liquidus temperature are studied. Nine reflow profiles for SAC 305 and nine reflow profiles for SnPb have been developed with three levels of peak temperature (230 o C, 240 o C, and 250 o C for SAC 305; and 195 o C, 205 o C, and 215 o C for SnPb) and three levels of time above solder liquidus temperature (30 sec., 60 sec., and 90 sec.). The shear force data of four different sizes of chip resistors (1206, 0805, 0603, and 0402) are compared across the different profiles. The shear force of the resistors is measured at time 0 (right after assembly). The fracture surfaces have been studied using a scanning electron microscopy (SEM) with energy dispersive spectroscopy (EDS)
Technical Library | 2023-09-07 14:38:31.0
A repeat customer specializing in high-technology interconnect, sensor, and antenna solutions, partnered with us to dispense small volumes of solder paste (Indium 10.1 SAC305 T6SG 78%m) onto backplane connectors – gold pads 0.175mm x 0.225mm. We performed a test requiring 0.200mm diameter or smaller dots to demonstrate the dispensing capability required.
Technical Library | 2010-07-08 19:56:15.0
As technology becomes increasingly reliant on electronics, understanding the reliability of lead-free solder also becomes increasingly important. This research project focused on phase transformation kinetics with the lead-free solder SAC 305. Today in the electronics industry, SAC 305 is the most widely used solder, making it a high priority to understand its long-term stability and performance in a variety of service conditions. Recent evidence has shifted the focus from thermal aging to reflow temperature and time above liquidus values during initial solder melting.
Technical Library | 2021-09-08 14:23:27.0
Although the electronics industry has largely settled on the use of SAC alloys for the assembly of the majority of lead free products, debate continues to exist over which SAC alloy – SAC305 (Sn3.0Ag0.5Cu) or SAC405 (Sn3.8Ag0.8Cu) – to use. The North American industry generally favours SAC405, while the Asian industry favours SAC305. SAC305 has the significant benefit of being less expensive than SAC405 owing to its lower silver content. However, there are lingering questions about whether the reliability of SAC305 is comparable to that of SAC405. Recent studies have concluded that no significant difference exists, but many potential applications were not studied. This paper compares the results of reliability testing of SAC305 and SAC405 in three different cases on a test vehicle representative of a mid-complexity server-type product which included a range of component types from CBGAs to discrete resistors.
Technical Library | 2010-04-29 21:40:37.0
The purpose of this paper is to investigate the effects of reflow time, reflow peak temperature, thermal shock and thermal aging on the intermetallic compound (IMC) thickness for Sn3.0Ag0.5Cu (SAC305) soldered joints.
Technical Library | 2011-08-25 17:47:23.0
While SnAgCu (SAC) alloys still dominate Pb-free selection in North America, especially Sn3.0Ag0.5Cu (SAC305), there are alternative material systems available. Any OEM that is concerned about the high reflow temperatures of SAC or relies on ODM, it is im
Technical Library | 2009-01-15 00:42:58.0
Tin-silver-copper has received much publicity in recent years as the lead-free solder of choice. SAC305 was endorsed by the IPC Solder Value Product Council in the United States as the preferred option for SMT assembly; most assemblers have transitioned to this alloy for their solder paste requirements. The SAC305 alloy due to its 3.0% content of silver is expensive when compared to traditional 63/37 for this reason many wave assemblers are opting for less costly options such as tin-copper based solders for their wave, selective and dip tinning operations.
Technical Library | 2014-08-07 15:13:44.0
Gold embrittlement in SnPb solder is a well-known failure mechanism in electronic assembly. To avoid this issue, prior studies have indicated a maximum gold content of three weight percent. This study attempts to provide similar guidance for Pb-free (SAC305) solder. Standard surface mount devices were assembled with SnPb and SAC305 solder onto printed boards with various thicknesses of gold plating. The gold plating included electroless nickel immersion gold (ENIG) and electrolytic gold of 15, 25, 35, and 50 microinches over nickel. These gold thicknesses resulted in weight percentages between 0.4 to 7.0 weight percent.
Technical Library | 2016-09-01 16:21:11.0
Sn3.0Ag0.5Cu (SAC305) is currently the most popular near eutectic lead-free alloy used in the manufacturing processes. Over the last several years, the price of silver has dramatically increased driving a desire for lower silver alloy alternatives. As a result, there is a significant increase in the number of alternative low/no silver lead-free solder alloys available in the industry recently. Our previous study showed that many alternative low silver solder paste materials had good printing and wetting performance as compared to SAC305 solder pastes. However, there is lack of information on the reliability of alternative alloy solder joints assembled using alternative low silver alloy solder pastes.In this paper, we will present the reliability study of lead-free solder joints reflowed using various lead-free alloy solder pastes after thermal cycling test (3000 cycles, 0°C to 100°C). Six different lead-free pastes were investigated. SAC305 solder joints were used as the control. Low and no silver solder pastes and a low temperature SnBiAg solder pastes were also included.
Technical Library | 2020-09-23 21:29:25.0
The electronics industry could benefit greatly from using a reliable, manufacturable, reduced temperature, SMT solder material (alloy-composition) which is cost competitive with traditional Sn3Ag0.5Cu (SAC305) solder. The many possible advantages and some disadvantages / challenges are discussed. Until recently, the use of Sn/Bi based materials has been investigated with negative consequences for high strain rate (drop-shock) applications and thus, these alloys have been avoided. Recent advances in alloy "doping" have opened the door to revisit Sn/Bi alloys as a possible alternative to SAC-305 for many applications. We tested the manufacturability and reliability of three low-temperature and one SAC-305 (used as a control) solder paste materials. Two of these materials are doped Sn/Bi/Ag and one is just Sn/Bi/Ag1%. We will discuss the tests and related results. And lastly, we will discuss the prospects, applications and possible implications (based on this evaluation) of these materials together with future actions.
