Technical Library | 2021-08-25 16:34:37.0
As the traditional eutectic SnPb solder alloy has been outlawed, the electronic industry has almost completely transitioned to the lead-free solder alloys. The conventional SAC305 solder alloy used in lead-free electronic assembly has a high melting and processing temperature with a typical peak reflow temperature of 245ºC which is almost 30ºC higher than traditional eutectic SnPb reflow profile. Some of the drawbacks of this high melting and processing temperatures are yield loss due to component warpage which has an impact on solder joint formation like bridging, open defects, head on pillow.
Technical Library | 2007-12-06 11:37:15.0
Over the past 30 years we have learned that lead has negative affects on the health of humans and seen strong legislation remove it from gasoline and paints. More recently, governments in Europe and Asia have set deadlines to remove lead from consumer electronic devices that use printed circuit boards. Currently, the ban is not being applied to high reliability applications such as military or medical devices, but we all know that will come someday soon. Likewise many believe that lead free solder is coming to wafer bump reflow and are beginning to make the transition.
Technical Library | 2013-12-19 16:57:50.0
With the adoption of RoHS and implementation of Lead Free solders a major concern is how this will impact reliability. Both commercial and military hardware are impacted by this change even though military hardware is considered exempt from the requirements of RoHS. As the supply chain has moved to the new lead free alloys both markets are being forced to understand these impacts and form risk mitigation strategies to deal with the change. This paper documents the effect of mixing Leaded and Lead Free alloys on BGA devices and how this impacts reliability. Three of the most common pitch BGA packages are included in the study to determine if the risk is the same as pitches decrease
Technical Library | 2003-04-18 12:05:57.0
The popular tin (Sn) rich lead free solders are causing severe corrosion to many of the materials used in today's Wave Solder systems. Users are experiencing higher maintenance frequency and reduced life of wave solder machine components. This paper describes the effects of Sn rich solders in contact with various materials and discusses alternate methods to alleviate this problem.
Technical Library | 2023-11-27 18:19:40.0
This page introduces major causes and countermeasures of solder crack in MLCCs (Multilayer Ceramic Chip Capacitors). Major causes of solder cracks Solder cracks on MLCCs developed from severe usage conditions after going on the market and during manufacturing processes such as soldering. Applications and boards that specially require solder crack countermeasures Solder cracks occur mainly because of thermal fatigue due to thermal shock or temperature cycles or the use of lead-free solder, which is hard and fragile.
Technical Library | 2023-09-26 19:14:44.0
The transition from tin-lead to lead free soldering in the electronics manufacturing industry has been in progress for the past 10 years. In the interim period before lead free assemblies are uniformly accepted, mixed formulation solder joints are becoming commonplace in electronic assemblies. For example, area array components (BGA/CSP) are frequently available only with lead free Sn-Ag-Cu (SAC) solder balls. Such parts are often assembled to printed circuit boards using traditional 63Sn-37Pb solder paste. The resulting solder joints contain unusual quaternary alloys of Sn, Ag, Cu, and Pb. In addition, the alloy composition can vary across the solder joint based on the paste to ball solder volumes and the reflow profile utilized. The mechanical and physical properties of such Sn-Ag-Cu-Pb alloys have not been explored extensively in the literature. In addition, the reliability of mixed formulation solder joints is poorly understood.
Technical Library | 2007-11-15 15:54:44.0
At the contractor level once a product is required to be soldered with lead-free solders all the processes must be assessed as to insure the same quality a customer has been accustomed to with a Sn63Pb37 process is achieved. The reflow, wave soldering and hand assembly processes must all be optimized carefully to insure good joint formation as per the appropriate class of electronics with new solder alloys and often new fluxes.
Technical Library | 2007-07-12 14:29:37.0
Over the last ten years, there have been a large number of publications describing work into lead free electronics soldering. They have come from all regions of the world and from academic organisations, individual companies and consortia. Although a number of these studies have culminated in "production trials", these have invariably been on a limited scale and they were essentially a demonstration, rather than the first step to implementation.
Technical Library | 2014-06-23 14:50:52.0
It was unusual to see chip terminations change colors when tin lead solders were used but with the introduction of lead free reflow soldering and the corresponding increases in reflow temperatures terminations are now changing colors. Two conditions are present when reflow temperatures are increased for lead free solder alloys that leads to discoloration. Reflow temperatures are above the melting point of tin (Sn MP is 232oC). Air temperatures commonly used in forced convection reflow systems are high enough to both melt the tin plating on the termination allowing it to be pulled into the solder joint due to solder joint liquid solder surface tension leaving behind the exposed nickel barrier. Now those metal oxide colors will be visible due to high air temperatures during reflow.
Technical Library | 2014-03-27 14:50:01.0
Because of the phase out of CFC's and HCFC's, standard solder pastes and fluxes evolved from RA and RMA fluxes, to No-Clean, to low residue No-Clean, to very low residue No-Clean. Many companies came out with their cleaning solutions, aqueous and semi-aqueous, with each product release being more innovative than the previous one. Unfortunately for most of the suppliers of cleaners, two other trends appeared; lead-free soldering and the progressive miniaturization of electronic devices.
