Facilitating intermetallic formation in wire bonding by applying a pre-ultrasonic energy

Diffusion Bonding of Al7075 to Ti-6Al-4V by Spark Plasma Sintering and Using a Copper Interlayer

“…This is due in part to the fact that the formation of IMCs is a result of atomic diffusion, which is the essential bonding process. In addition, and very special to our case here, the formation of IMCs is associated with the fragmentation of the Al 2 O 3 oxide layer that usually forms on the Al7075 surface and would rather act as a barrier to diffusion [19,20], which is an advantage of using the SPS technique, as discussed above. These possible enhancements are, however, conditional on a good distribution of the IMCs at the interface (both laterally and across the interface), and on the "degree of absence" of voids and microcracks in the diffusion layer.…”

Microstructural evaluation and failure analysis of Ag wire bonded to Al pads

“…11. Xu et al [34][35][36][37][38] have reported on the effects of the bonding parameters on the microstructural evolution to solve the problems associated with the alumina layer in Au-and Cu-Al bonds, and some of these inter- pretations were adopted in this study to understand similar problems in Ag-Al bonding. For example, ultrasonic power can sweep away the alumina layer and facilitate a direct contact between the Ag and Al [35,36].…”

“…A prolonged bonding time and high temperature can break the alumina layer while at the same time, promote the formation of continuous AgAl IMCs [37]. The pre-ultrasonic treatment can initiate the formation of Ag-Al IMCs in both the peripheral and central regions of the Ag-Al bond [38]. Further studies are still required to establish the optimum conditions for the Ag-Al bond.…”

Cu/Cu direct bonding by metal salt generation bonding technique with organic acid and persistence of reformed layer

“…The problem is that an actual bonding surface consists of an oxide film and a machined layer; [3][4][5][6][7] therefore, adhesion between surfaces at the bond interface and removal of the oxide film represent necessary requirements to obtain high bond strength. Recently, ultrasonic vibration, [8][9][10][11][12][13] plasma processing, [14][15][16][17][18][19] and organic acid pretreatment [20][21][22][23] have been investigated as methods for breaking and cleaning a superficial oxide film. Indeed, in a previous study, we showed that modification of an oxide film with formic acid greatly improves the strength of bonding between tin surfaces 22) and between tin and copper.…”