Encapsulating material must be used for the mechanical and electrical protection of bare, wine bonded components mounted on the panel. These materials are high-purity one-component epoxy adhesives, which can be classified into two types:
With Glob Top technology, the rheology of the material is very important, so that the casing material flows between the bonding wires, but does not flow through the panel during curing.
For thinner wires, a dam is first formed from a high-viscosity thixotropic adhesive, and then the component is covered with a low-viscosity material. This is Dam & Fill technology. The two materials are cured in one step. According to curing, it can be a material that hardens to UV light or to heat treatment. These materials are used not only for the encapsulation of bare chips, but also for encryption.


Underfill materials

BGA, flip-chip, CSP alkatrészek megbízhatóságának növelésére kifejlesztett ragasztók. Az alkatrészeket a panelhez rögzítik, így csökkentik a forraszkötések mechanikai terhelését.

Adhesives developed to increase the reliability of BGA, flip-chip, CSP components. The components are attached to the panel, thus reducing the mechanical stress on the solder joints.
Among the underfill materials, we distinguish panel-level (for encapsulated BGA components) and component-level (for unencapsulated Flip Chip components) underfill materials.
The most common are the capillary-flow materials, which after soldering are dispensed in an L-shape next to the component, and from there the capillary effect forces the adhesive to flow under the part, filling the space between the soldering balls. In addition, the so-called “Fluxing Underfill” materials are also available. When using this type of material, we do not apply solder paste under the BGA components, but instead add the underfiller material combined with the flux to the panel. Place the component in this. During soldering, it acts as a flux, promotes the fusion of the molten solder balls and the soldering surface, and then hardens after reflow. 
Newer capillary flow materials do not require preheating of the panel, so the process can be simpler and safer.
For high-reliability electronics, materials with a high Tg (glass transition temperature) and low coefficient of thermal expansion provide the best solution.
For portable equipment, repairability may arise as a requirement. This can also be solved with underfill materials that allow rework.

Corner Bond adhesives

Instead of underfills, we can also use Corner Bond adhesives for certain applications. Uploading them can be easier than underfilling. The mechanical load is taken over in the same way as underfills, but they do not fill the air space under the part.

Alátöltések helyett bizonyos alkalmazásokhoz használhatjuk az alkatrészeket a sarkain rögzítő (Corner Bond) ragasztóanyagokat is.

Talk to our expert

Császár Csaba
salesperson, technical consultant, certified IPC-A-610 and IPC/WHMA-A-620 master trainer, IPC-A-600 and IPC-6012 trainer
+36 20 501 9909