Ultrafast Photonic Soldering with Sn–58Bi Using Intense Pulsed Light Energy

Abstract

Solders, which are the most commonly used materials in electronic packaging, have been widely used for electrical interconnections. When producing a solder joint, a layer is formed on the contact pad, followed by a reflow process conducted using infrared or thermal energy. This process requires a high‐temperature environment and long heating time. Herein, an advanced approach involving photonic soldering using intense pulsed light (IPL) energy is examined thoroughly. In particular, the relation between the bonding characteristics and pulse conditions, such as the energy, frequency, and number, for the development of ultrafast, low‐damage, and large‐area bonding technology is studied. Compared with the conventional reflow, IPL soldering requires a process time of only ≈2.5% and can improve the strength by 40%. Fracture micrographs after the die shear test indicate an interfacial fracture after conventional reflow and a mixed fracture after IPL soldering; this results in the consumption of the Cu layer after the time‐consuming reaction in the reflow and the formation of an extremely refined region in the solder joint after irradiation with IPL energy. Because of its improvement with respect to the process and bonding characteristics, IPL soldering can be a candidate for innovative interconnections in microelectronics.

Effects of Cu/SnAgCu Powder Fraction and Sintering Time on Microstructure and Mechanical Properties of Transient Liquid Phase Sintered Joints

“…TLPS thus is accompanied with a long bonding time [18][19][20]. Many approaches have been employed to accelerate the sintering time such as high-temperature/pressure bonding [19,21,22], incorporation of reactive additives [23][24][25][26], surface modification [27,28], and electric/laser-assisted bonding [29][30][31][32][33][34]. For instance, Ramli et al employed TiO 2 particles to reduce the thickness of the interfacial IMCs for the enhancement of the shear strength and hardness of the solder joints [24].…”

Microstructural Optimization of Sn-58Bi Low-Temperature Solder Fabricated by Intense Pulsed Light (IPL) Irradiation

“…Only a limited number of documented instances involve the application of IPL soldering to Sn-based solder formulations within operational electronic packages [11][12][13][14][15][16]. Jung et al [11] presented findings detailing the IPL soldering of Sn-58Bi, illustrating a mere 2.5% duration requirement relative to conventional reflow techniques, alongside a 40% enhancement in mechanical strength.…”

“…Only a limited number of documented instances involve the application of IPL soldering to Sn-based solder formulations within operational electronic packages [11][12][13][14][15][16]. Jung et al [11] presented findings detailing the IPL soldering of Sn-58Bi, illustrating a mere 2.5% duration requirement relative to conventional reflow techniques, alongside a 40% enhancement in mechanical strength. Ha et al [12] conducted an evaluation of the reliability impact on Sn-3.0Ag-0.5Cu ball grid array (BGA) packages with Electroless Nickel Electroless Palladium Immersion Gold (ENEPIG) surface treatment, employing the IPL soldering methodology.…”

Intense Pulsed Light Soldering of Sn–3.0Ag–0.5Cu Ball Grid Array Component on Au/Pd(P)/Ni(P) Surface‐Finished Printed Circuit Board and Its Drop Impact Reliability

“…Previously, most studies have mainly focused on printed electronics, [ 13–16 ] whereas only a few studies on IPL soldering and the reliability of the resulting solder joints have been reported. [ 17–19 ] Herein, we investigated IPL soldering as an alternative technology to reflow soldering. We formed solder joints using Sn–3.0Ag–0.5Cu lead‐free solder (SAC305) and a PCB with an electroless‐nickel/electroless‐palladium/immersion‐gold (ENEPIG) surface finish through IPL soldering.…”