Perfect 40micron pitch solder bump reflowed by LSR
Laser Process Recipe : Bonding Quality
LSR needs shorter TAL(time above liquidous) compared to Mass Reflow
Cooling speed is directly related to formation of multi grain and uniform & thin formation of Intermetallic compounds
Multi-Grain and uniform and thin IMC(Intermetallic Compound) layer provides strong Shear Strength and highly stable Shear Fatigue.
IMC Layer : LSR vs MR/TCB
A : 1sec
B : 5sec
MR : 65sec
Thickness of Intermetallic Compound(IMC) of LSR is ¼ thinner.
Material characteristic of IMC is normally Brittle.