Technical Library | 2014-10-02 20:10:07.0
Sn3.0Ag0.5Cu (SAC305) is 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 the results, there is a significant increase in the number of alternative low/no silver lead-free solder alloys available in the industry recently.In this paper, we'll present the performance and process capability of various low/no silver alloy solder pastes. Data from printability, wetting test, slump test, solder ball test, voiding, etc… will be discussed and compared with the control SAC305 solder paste. Benefits and concerns of using low/no silver alloy solder paste materials will also be addressed.
Technical Library | 2015-02-19 16:54:34.0
Pad cratering is an important failure mode besides crack of solder joint as it’ll pass the regular test but have impact on the long term reliability of the product. A new pin pull test method with solder ball attached and positioning the test board at an angle of 30º is employed to study the strength of pad cratering. This new method clearly reveals the failure mechanism. And a proper way to interpret the finite element analysis (FEA) result is discussed. Impact of pad dimension, width and angle of copper trace on the strength is included. Some findings not included in previous research could help to guide the design for better performance
Technical Library | 2015-02-27 16:46:30.0
During the last period of newly assembled electrical devices (pcbs), new component types like LGA and QFN were also qualified as well as smaller passive components with reliability requirements based on the automotive and industrial industry. In the narrow gaps under components, residues can accumulate more by the capillary forces. This is not that much a surface resistance than an interface issue. Also that the flux residues under such types of components creates interaction with the solder resists from the pcb, as well as the component body was not completely described in the standard SIR measurement. On the other hand also, electrical influence with higher voltage creates new terms and conditions, in particular the combination of power and logic in such devices. The standard SIR measurement cannot analyze those combinations.The paper will discuss the requirements for a measurement process, and will give results. The influences of the pcb and component quality will also be discussed. Furthermore it will describe requirements for nc solder paste to increase the chemical/thermical/electrical reliability for whole devices
Technical Library | 2021-04-21 15:10:16.0
Voids affect the thermal characteristics and mechanical properties of a solder joint, thereby affecting the reliability of the solder interconnect. The automotive sector in particular is requiring the mitigation of solder voids in various electronic control modules to the minimum possible level. Earlier research efforts performed to decrease voids involved varying the reflow profile, paste deposit, paste alloy composition, stencil aperture, and thickness. Due to the various advantages they offer, the use of Ball Grid Array packages is common across all industry sectors. They are also prone to process voiding issues. This study was performed to determine if vacuum assisted reflow process can help alleviate the voids in area array solder joints. Test parameters in this study largely focused on vacuum pressure level and vacuum dwell time.
Technical Library | 2022-10-31 18:35:40.0
Voids affect the thermal characteristics and mechanical properties of a solder joint, thereby affecting the reliability of the solder interconnect. The automotive sector in particular is requiring the mitigation of solder voids in various electronic control modules to the minimum possible level. Earlier research efforts performed to decrease voids involved varying the reflow profile, paste deposit, paste alloy composition, stencil aperture, and thickness. Due to the various advantages they offer, the use of Ball Grid Array packages is common across all industry sectors. They are also prone to process voiding issues. This study was performed to determine if vacuum assisted reflow process can help alleviate the voids in area array solder joints. Test parameters in this study largely focused on vacuum pressure level and vacuum dwell time.
Technical Library | 2013-06-13 15:31:24.0
Electromigration (EM) is a mass transportation mechanism driven by electron wind force, thermal gradient, chemical potential and stress gradient. According to Moore’s law, number of transistors on integrated circuits (ICs) doubles approximately every 2 years. Moore’s law holds true since its introduction in 1970s. This insatiable demand for smaller ICs size, larger integration and higher Input/Output (IO) count of microelectronics has made ball grid array (BGA) the most promising connection type in electronic packaging industry. This trend, however, renders EM reliability of solders joints a major bottleneck to hinder further development of electronics industry...
Electronic Packaging Laboratory, State University of New York
Technical Library | 2016-01-21 16:52:27.0
Solder paste has long been viewed as "black magic". This "black magic" can easily be dispelled through a solder paste evaluation. Unfortunately, solder paste evaluation can be a challenge for electronic assemblers. Interrupting the production schedule to perform an evaluation is usually the first hurdle. Choosing the solder paste properties to test is simple, but testing for these properties can be difficult. Special equipment or materials may be required depending upon the tests that are chosen. Once the testing is complete, how does one make the decision to choose a solder paste? Is the decision based on gut feel or hard data?This paper presents a process for evaluating solder pastes using a variety of methods. These methods are quick to run and are challenging, revealing the strengths and weaknesses of solder pastes. Methods detailed in this paper include: print volume, stencil life, response to pause, open time, tack force over time, wetting, solder balling, graping, voiding, accelerated aging, and others.
Technical Library | 2021-12-16 01:33:11.0
Ball Grid Array devices, BGAs, are widely used in a vast range of products including consumer, telecommunications and office based systems. As an area array device of solder joints, it provides high packing density with a relatively easy introduction cycle. However, over the last couple of years engineers have started to experiment, and in some cases implement, stacked packages, of the type often called Package on Package, or POP. In simple terms, POP devices are the stacking of components, one on top of the other, either during the original component manufacture or during printed board assembly.
Technical Library | 2021-09-08 14:10:12.0
The Pb-Free Alloy Characterization Program sponsored by International Electronics Manufacturing Initiative (iNEMI) is conducting an extensive investigation using accelerated temperature cycling (ATC) to evaluate ball grid array (BGA) thermal fatigue performance of 12 commercial or developmental Sn based Pb-free solder alloys. This paper presents the initial findings from a specific subset of the temperature cycling test matrix. The focus is on comparing alloy performance for two of the most commonly specified temperature cycles, 0 to 100 °C and -40 to 125 °C.
Technical Library | 2015-01-05 17:38:26.0
The impact of voiding on the solder joint integrity of ball grid arrays (BGAs)/chip scale packages (CSPs) can be a topic of lengthy and energetic discussion. Detailed industry investigations have shown that voids have little effect on solder joint integrity unless they fall into specific location/geometry configurations. These investigations have focused on thermal cycle testing at 0°C-100°C, which is typically used to evaluate commercial electronic products. This paper documents an investigation to determine the impact of voids in BGA and CSP components using thermal cycle testing (-55°C to +125°C) in accordance with the IPC-9701 specification for tin/lead solder alloys. This temperature range is more typical of military and other high performance product use environments. A proposed BGA void requirement revision for the IPC-JSTD-001 specification will be extracted from the results analysis.
