Knocking Down the Bone Pile: Revamp Your Components with BGA Reballing
Global Sourcing Spotlight: Balancing Speed and Flexibility Without Sacrificing Control
SMT Perspectives & Prospects: Artificial Intelligence Part 6: Data Module 1
Book Excerpt: The Printed Circuit Assembler’s Guide to... Low-Temperature Soldering, Vol. 2
June 18, 2024 | I-Connect007 Editorial TeamEstimated reading time: 1 minute
The Printed Circuit Assembler’s Guide to... Low-Temperature Soldering, Vol. 2, by Morgana Ribas, et al, MacDermid Alpha Electronics Solutions
Chapter 1: Introduction to Low-temperature Soldering
Low-temperature solders (LTS) continue to attract serious interest from the electronics industry. These solder alloys enable the use of lower glass transition temperature (Tg) substrates and components due to the lower processing temperature, promote long-term reliability by reducing exposure to thermal excursion, and enable organizations to meet sustainability targets. Perhaps more significantly, low-temperature soldering is an enabling technology that mitigates warpage-induced defects of the ultra-thin, high IO chip-scale packages used in complex electronic devices. Use of higher reflow temperature Sn-Ag-Cu (SAC) solders in package-on-package (PoP) bottom and PoP memory technology can potentially result in soldering defects such as non-wet opens, solder bridging, and head-in-pillow.
The eutectic 42Sn-58Bi alloy melts at 138°C and has been considered for SMT soldering since the transition from tin-lead to lead-free solders. This alloy is quite interesting as a solder, as bismuth is one of the few elements forming a solid solution in tin. Its binary composition, lamellar microstructure, and eutectic melting point resemble that of eutectic tin-lead. However, this first-generation LTS alloy lagged behind traditional lead-free alloys in solder joint thermomechanical and drop shock reliability and limited thermal cycling performance.
The transition to lead-free solders was motivated by regulatory compliance, and SAC305 (96.5% tin, 3% silver, 0.5% copper) was chosen as the best cost-benefit alternative. As the electronics industry evolved, so did solder joint reliability requirements. Several new solders were introduced to meet specific reliability requirements.
Share on:
Testimonial
"In a year when every marketing dollar mattered, I chose to keep I-Connect007 in our 2025 plan. Their commitment to high-quality, insightful content aligns with Koh Young’s values and helps readers navigate a changing industry. "
Brent Fischthal - Koh YoungSuggested Items
Indium Experts to Deliver Technical Presentations at SMTA International
10/14/2025 | Indium CorporationAs one of the leading materials providers to the power electronics assembly industry, Indium Corporation experts will share their technical insight on a wide range of innovative solder solutions at SMTA International (SMTAI), to be held October 19-23 in Rosemont, Illinois.
Meet the Author Podcast Features Dr. Pritha Choudhury
09/24/2025 | I-Connect007I-Connect007 announces the latest episode of its Meet the Author podcast series, spotlighting Dr. Pritha Choudhury, a co-author of The Printed Circuit Assembler’s Guide to Low-temperature Soldering, Volume 2. In this conversation with SMT007 Managing Editor Nolan Johnson, Dr. Choudhury explains why a second volume was essential and explores the real-world factors accelerating the adoption of low-temperature soldering across the electronics manufacturing industry.
ROHM Develops Ultra-Compact CMOS Op Amp: Delivering Industry-Leading Ultra-Low Circuit Current
09/11/2025 | ROHMROHM’s ultra-compact CMOS Operational Amplifier (op amp) TLR1901GXZ achieves the industry’s lowest operating circuit current.
Indium Corporation to Highlight High-Reliability Solder Solutions at SMTA Guadalajara Expo
09/04/2025 | Indium CorporationIndium Corporation, a leading materials refiner, smelter, manufacturer, and supplier to the global electronics, semiconductor, thin-film, and thermal management markets, will feature a range of innovative, high-reliability solder products for printed circuit board assembly (PCBA) at the SMTA Guadalajara Expo and Tech Forum, to be held September 17-18 in Guadalajara, Mexico.
INEMI Interim Report: Interconnection Modeling and Simulation Results for Low-Temp Materials in First-Level Interconnect
05/30/2025 | iNEMIOne of the greatest challenges of integrating different types of silicon, memory, and other extended processing units (XPUs) in a single package is in attaching these various types of chips in a reliable way.