Solder ball production

Keywords Discrete polydisperse spray Electric droplet charging Extension nozzle Ink-jet printing Monodisperse droplet stream Monodisperse spray Multihole orifice Modulated jet excitation Nozzle hole shapes Rapid prototyping Rayleigh-type jet break-up Solder ball production... 

Solder Balls. Some assembly processes are more prone to generate solder balls than others. Prequahfication of the solder mask with the assembly chemistries and processes is essential to predict production performance. If solder balk occur during assembly, in some cases they can be reduced by using a mask with a different surface finish. Satin or matte products sometimes have less of a tendency to have solder balls. Modifying the solder mask cure can have an effect on the level of solder balls also—consult with the solder mask supplier before deviating from its recommended cure process. 

Visual inspection often occurs at the end of the assembly process or even after all of the electrical tests on the assembly have been completed. It is not possible, however, for invisible or hidden joints. The visual inspector looks for scratches, partial delaminations, solder splashes or solder balls away from solder joints, and any other condition that does not affect assembly performance but does make the assembly look as though it might not be a high-quality product. 

The production of manufactured lead components is responsible for an important part of total lead consumption. Lead surfaces oxidize readily, leaving the surface resistant to corrosion. Lead is used in construction when corrosion resistance is desired. Roofing, flashing, wall cladding, and sound insulation are all instances where lead is used. Alloys of lead are used in solder, ball bearings, brasses, typesetting metal, collapsible tubes, and radiation shielding. The manufacture of ammunition is also a major consumer of lead. There are many additional uses of lead components, but these account for a small portion of total lead consumption [77]. 

The lead industry is undergoing dramatic change. Many products once made with lead no longer use the element. The purpose of this change is to reduce the amount of lead that gets into the environment. Examples of such products include ammunition, such as shot and bullets sheet lead used in building constmction solder water and sewer pipes ball... 

There are a number of methods available to avoid the tin pest reaction, although some are not practical. Clearly, the tin pest reaction will not occur if the temperature is not reduced below the transformation temperature. Unfortunately, the transformation temperature is not so low that it can be avoided either during product use or shipping therefore temperature control is not an acceptable solution. The imposition of a compressive stress is known to inhibit the transformation. This may be useful in some applications, for example, the underfill used in conjunction with flip chip solder joints (C4) exerts a compressive stress on the joints as the volume increases during the tin pest reaction. The effect of the compressive stress may be sufficient to eliminate or retard the tin pest transformation. Unfortunately, this mechanism would not apply to solder joints not utilizing an underfill material such as ball grid array (BGA) and other surface-mounted components [65]. 

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