Effect of Co content on the microstructure, spreadability, conductivity and corrosion resistance of Sn-0.7Cu alloy

Microstructural and Mechanical Characterization of Cu/Sn Slid Bonding Utilizing Co as Contact Metallization Layer

“…Taking into account the specifically required considerations for some MEMS devices, such as CMOS compatibility, avoiding the chemical deposition on the device wafers, and chemical compatibility with the Cu-Sn SLID bonding, Co contact metallization is one of the plausible candidates [46]. In addition, it has been reported that Co can stabilize the HT-hexagonal Cu 6 Sn 5 , suppress Cu 3 Sn formation, and speed up IMC formation in the Cu-Sn SLID bonding system, which can reduce the SLID processing time and cost [46,55,56]. The microstructural evolution of the Co metal in contact with Cu-Sn has been previously investigated; depending on the bonding condition, various IMCs (such as (Cu,Co) 6 Sn 5 , Cu 3 Sn, (Co,Cu) Sn and (Co,Cu)Sn 3 ) can be evolved in the joint area [46,[56][57][58].…”

“…In addition, it has been reported that Co can stabilize the HT-hexagonal Cu 6 Sn 5 , suppress Cu 3 Sn formation, and speed up IMC formation in the Cu-Sn SLID bonding system, which can reduce the SLID processing time and cost [46,55,56]. The microstructural evolution of the Co metal in contact with Cu-Sn has been previously investigated; depending on the bonding condition, various IMCs (such as (Cu,Co) 6 Sn 5 , Cu 3 Sn, (Co,Cu) Sn and (Co,Cu)Sn 3 ) can be evolved in the joint area [46,[56][57][58]. Our previous study on the microstructural evolution of the Co bulk in contact with Cu-Sn electroplated silicon chips has shown that a fully IMC-bonded joint can be successfully achieved only if a thin layer of Co (Co thickness/ Sn thickness ≤ 4%) is in contact with the Cu-Sn SLID system.…”

“…Previous research [46,[55][56][57][59][60][61] nonetheless contains gaps regarding utilizing Co as a single contact metallization layer or part of a metallization stack for the Cu-Sn SLID bonding system. For example, amongst the available literature, the Young's modulus and hardness values of (Cu,Co) 6 Sn 5 (which is the targeted IMC to grow in the Co-Sn-Cu system based on our previous finding s), and tensile fracture mode of the joint are lacking.…”

Effect of Multiple Reflows on the Interfacial Reactions and Mechanical Properties of an Sn-0.5Cu-Al(Si) Solder and a Cu Substrate

“…Therefore, research on the formation and growth of IMC layers in multiple reflows or thermal aging environments is essential [ 16 , 17 ]. In this regard, studies have been conducted to improve microstructures and mechanical properties by adding small amounts of trace elements to Sn-Cu solder with relatively high melting points [ 18 , 19 , 20 , 21 , 22 ]. The addition of trace elements can reduce the diffusion velocity of IMCs by lowering the activity of Cu and Su elements or by blocking the diffusion path of atoms in liquid–solid reaction conditions [ 23 , 24 ].…”

Revealing the Effect of Phase Composition and Transformation on the Mechanical Properties of a Cu–6Ni–6Sn–0.6Si Alloy

“…It is well known that the mechanical properties depend on the microstructures; thus, the microstructure evolution and influencing factors should be researched systematically. Alloying elements added into the copper-nickel-tin alloys can affect the microstructures of the alloys, causing the mechanical properties of the alloys to vary [13][14][15][16][17][18][19][20][21]. A lot of research shows that the segregation suppression of Sn during the solidification process and the inhibition of the discontinuous precipitation of the γ phase during the heat treatment process are two difficulties which can directly influence their comprehensive performance and application in copper-nickel-tin alloys with high Ni and Sn contents [22][23][24][25][26].…”