In reflow soldering process of SMT process, SMT components produce by up and take off the welding defects, people image is called "erection" phenomenon (i.e., Manhattan phenomenon).
"Erection" phenomenon occurred in the CHIP components, such as SMD capacitor and SMD resistor reflow soldering process, the smaller element size likely to happen. The reason is that components on both ends of the solder paste on the bonding pad in reflux melts, two welding on the surface tension of element is not balanced. Concrete analysis has the following 7 kinds of main reason:
1) the uneven heating Backflow of uneven distribution of temperature in the furnace temperature distribution is not uniform
2) element to the problem of welding welding on the shape and size differences weldability difference big components are too lightweight
3) substrate material and the thickness