The development of new SMT printing techniques for mixed technology (heterogeneous) assembly

As electronics assemblies continue to shrink in form factor with decreasing component sizes, and an ever increasing mix and density of components, the Surface Mount assembly process is becoming increasingly challenged. A new printing technique has been developed which will allow next generation ultra fine pitch components (such as 0.3mm pitch CSP's, 01005's) to be printed alongside standard SMT components using a single thickness stencil and a traditional stencil printing approach. Results indicate that today's accepted stencil area ratio rules which govern solder paste transfer efficiency can be significantly pushed out to extend stencil printing process capabilities to stencil apertures having area ratios as low as 0.4. Such a breakthrough will allow heterogeneous assembly to satisfy up and coming mixed technology demands.