With the advances and improvements in technology of the electronics industry, the scale of components used has consistently grown smaller. This has allowed for more efficient use of resources (a silicon chip that once held hundreds of transistors now holds millions) and more convenient and consumer friendly products (palm sized computers compared to warehouse sized computers forty years ago). However, as advances lead to decreases in the scale of components, similar advances must be made in the production process in order to assemble these components. One method used in current printed circuit board assembly is attaching components to the board with a surface mount adhesive (SMA). When applying the SMA, it is vital that the adhesives not cover any part of the leads, as this may decrease the quality of the solder connection. As components decrease in size, so does the gap between the leads. It is therefore necessary for the size of the adhesive dot to decrease to the same degree as the components decrease. Current technology can product dots of surface mount adhesive of approximately 20 mil diameter and roughly 0.03-0.04 ml volume. Anticipating the continuing trend in component scale reduction, however, predicts that dots in the 6-10 mil diameter range will be required. Various dispensing methods are proposed here, including SAM jetting of "small dots". The underfilling of 3D-packages with small gaps, yet large geometries, that are required to accomplish thin packages, as well as the underfilling of small die present yet another challenge to the consistency and accuracy of dispensing processes. "Assisted Capillary Underfilling" for large die/components with small gaps (LDSG_ is proposed as a fast and reliable encapsulation process. The challenge of jetting abrasive materials is addressed here by monitoring wearout evolution on the jet itself and corresponding effects on the jetted fluid characteristics. This paper proposes a solution to this dispense challenge by way of the con-contact "Jetting Underfill" for both, traditional capillary flow and "Forced flow Underfilling", commonly known as "No-flow Underfilling".
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