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October 2015 • SMT Magazine 39 lar process or project of yours or your customer? what were the main challenges here? Weigel: When using the chip on board tech- nique, the chip is directly bonded on the PCB and then wire-bonded to apply electrical con- tact. The chip then gets encapsulated to protect tiny wires from damage. If a manufacturer uses the dam and fill method instead of a glob top to reach a low- er height, more process steps will be required. First, a high-viscous dam needs to be dispensed around the chip. Afterwards, the space is filled with a low-viscous system. While some prod- ucts on the market require intermediate curing steps, manufacturers with our adhesives can dispense what we call "wet in wet." This means that neither the single dams nor the entire wall must be cured intermediately, and even the fill can be dispensed before any curing takes place. Curing the complete encapsulation in one step results in reduced cycle times and thus a great increase in productivity. Las Marias: Please talk about best practices that will help assemblers and manufacturers reduce cy- cle times in their processes. Weigel: The most important thing is to take a holistic approach. We always recommend that our customers consider adhesives in the early design phases. It's only then that you can lever- age all benefits of bonding. Assigning the tasks of the assembly group, creating a specifications sheet for the adhesive, defining test meth- ods and parameters and working out different bonding processes should all be done early on. Las Marias: what does this mean in practice? Weigel: In terms of design, you should make sure that it is adhesive-friendly. When looking at a component level, its material, its prepara- tion and a potentially necessary pretreatment are all important. Considering the adhesive, you should also take its transport into account as well as its storage and handling. I would also think about the strain on the component and how to simulate this in the R&D phase. Lastly, I would take a look at the site of assembly, pro- duction facilities, suppliers, assembly parame- ters and the know-how of the employees. Las Marias: Can you give some examples as to how manufacturers can address this issue? Weigel: With light-curing, dual-curing and quicker heat-curing, we have already discussed different technologies to accelerate cycle times from an adhesive and a curing equipment per- spective. Other process components that can speed up production are using plasma if pre- treatment is beneficial and jet valves or eccen- tric screw pumps for dispensing. Las Marias: some assemblers say smt equipment such as pick-and-place machines are among the key issues when it comes to cycle time reduction. Please give your comments on this. Weigel: Understanding high-volume produc- tion processes is essential for an adhesive man- ufacturer. We have a department that special- izes in very specific applications. For example, one of our engineers may be well versed in all the fine details of chip encapsulation, while an- other may focus primarily on MEMS packaging processes. Delo has very specific equipment and ma- chines in its labs. For example, with our fully- automated die placer, we can re-produce cus- tomer processes under realistic circumstances reducInG cycLe tIMeS WIth InnoVAtIVe bondInG SoLutIonS chip encapsulation for automotive and industrial electronic products requires encapsulants with extremely good thermal and chemical resistance. FeATure inTerview