Laser-Assisted Bonding (LAB), Its Bonding Materials, and Their Applications

Abstract

Laser-Assisted Bonding (LAB) and its bonding materials help to find solutions to productivity, reduced warpage during fabricating modules, and fine-pitch bonding. Fluxing and hybrid underfill materials are developed to simplify the bonding process by eliminating the conventional underfill and cleaning process. We introduce two applications exhibiting the advantages of the LAB with two materials. Fluxing underfill was applied to bond a daisy chain chip with the minimum interconnection pitch of 30㎛ within 2 seconds. Hybrid underfill was used to fabricate a silicon back-contact solar module with reduced warpage, compared with the module fabricated through the conventional reflow process.

Low Melting Temperature Sn-Bi Solder: Effect of Alloying and Nanoparticle Addition on the Microstructural, Thermal, Interfacial Bonding, and Mechanical Characteristics

“…After aging at 100 • C for 400 h, the average eutectic size decreased from 4.59 µm to 2.37 µm, as much as 48.4% by adding SiC nanoparticles. Such refinement of a eutectic microstructure might have been due to the increased heterogeneous nucleation sites and impeded the phase or grain boundary movement by SiC nanoparticles [114][115][116]. Nanoparticles of oxides like ZrO 2 , CeO 2 , and Al 2 O 3 also reported to refine the solder microstructure [85][86][87][88].…”

“…That is, Sn-40%Bi-2%Zn-0.1%Cu solder had the highest UTS of 89.31 MPa, Sn-40%Bi-0.1%Cu of 82.45 MPa, and Sn-58%Bi of 73.24 MPa. The reason of increased strength can be that addition of Zn the solder produced uniform spheroidal shape of CuZn 2 particles that capture the moving dislocation and for dislocations piling up and fine needle-shape Zn [113,114]. Figure 8a shows the tensile strength of Sn58Bi solder upon the addition of various alloying elements.…”

91‐2: Transfer, Bonding, and Repair of LEDs for µLED Display Fabrication via Simultaneous Transfer and Bonding (SITRAB) Technology

“…Laser-assisted bonding (LAB) has been highlighted as a powerful solution for the heterogeneous integration of electronic and photonic devices due to its outstanding capability to perform finepitch interconnection within a few seconds [5]. A spatiotemporally controlled infrared (IR) laser induces the transient melting and cooling of solders, forming electrically/thermally conductive metallic bonding between devices and substrates [6].…”