Year: 2025
Type: article
Abstract: In this study, the laser soldering process was compared with the conventional reflow soldering process using a Sn- 3.0Ag-0.5Cu solder and an ENEPIG (Electroless Nickel-Electroless Palladium-Immersion Gold) surface-finished substrate. Laser soldering enables localized heating and shorter bonding time compared to reflow soldering, which reduces thermal damage to both the chip and the substrate. To evaluate the long-term thermal reliability, aging tests were conducted at 150 °C for up to 2000 h. Immediately after reflow soldering, (Cu, Ni)6Sn5 and (Ni, Cu)3Sn intermetallic compounds (IMCs) were formed at the joint interface, and the IMC layer thickness increased with aging time. In the case of laser-soldered joints, a very thin (Cu, Ni)6Sn5 layer was observed at the interface, and although its thickness increased with aging, (Ni, Cu)3Sn was not detected even after 2000 h of aging. After 2000 h, IMC spalling was observed at the interface. For both soldering processes, the shear strength decreased with increasing aging time, while the laser-soldered joints consistently showed higher values than those obtained by reflow soldering. All samples exhibited ductile fracture behavior.
Source: Journal of Welding and Joining
Authors: Hyo-Won Lee, Se-Hyeong Lee, Jeong-Won Yoon
Institutions: Chungbuk National University, Yonsei University
Language: English
Subfield: Electrical and Electronic Engineering
Field: Engineering
Domain: Physical Sciences
Open Access status: diamond
Awards: G5128263949, G5211539641, G6040491601
OpenAlex ID: W7117546599