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56 SMT Magazine • March 2015 artICle hIGh-rELIaBILITY ThankS TO aDhESIvES continues As various dispensing patterns can be set and reliably applied, dam and fill are the most accurate and suitable for these types of applica- tions. Yet, there may be instances where partial encapsulation with glob top products is possi- ble—and completely sufficient—as the flow of these materials is optimized. The special "dam stacking" procedure in- volves the stacking of several adhesive beads, creating a wall. The single "levels" must be cured individually. False. Some products on the market actu- ally require intermediate curing steps. However, certain systems can also be processed complete- ly "wet in wet." Neither the single dams nor the entire wall must be intermediately cured, and the fill can even be dispensed before any cur- ing takes place. Of course, this system has limits in regard to geometry, but curing the complete encapsulation in one step, results in a great in- crease in productivity. Functioning under extreme conditions, the reliable encapsulation of microelectronics pres- ents great challenges. Specially developed en- capsulants combine outstanding material prop- erties such as chemical resistance, mechanical properties, excellent adhesion, optimized dis- pensing and flowing properties and variable curing parameters. With their help, production processes can be designed more flexible and efficient, cutting down production costs and boosting output while receiving the highest product quality. SmT Kevin Balben is product specialist at delo. figure 3: Glob top partial encapsulation: Although limited in terms of geometry, glob top products may even be suitable for partial encapsulation due to an optimized flow. figure 5: dam stacking: Certain systems even allow a stacking of the dams without intermediate curing. figure 4: dam and fill partial encapsulation. dam and fill enables more complex and defined encapsulation designs.