| Name | Bottom filling adhesive |
| Synonyms | Bottom filling adhesive, dysprosium material bottom filling adhesive circuit board BGA bottom filling adhesive one-component low-temperature curing chip adhesive |
| Use | Underfill is a one-component epoxy resin potting material with high fluidity and high purity. It can fill the bottom of CSP and BGA chips through innovative capillary action, form a firm filling layer after heating and curing, reduce the stress impact caused by the difference of thermal expansion coefficient between the chip and the substrate, improve the structural strength and reliability of the components, and enhance the anti-drop performance between the chip and PCBA in BGA mounting mode. |
The application principle of the bottom fill glue is to use capillary action to make the glue flow quickly through the bottom of the BGA chip, and the minimum space for capillary flow is 10um. This also meets the minimum electrical characteristics requirements between the solder pad and the solder ball in the welding process, because the glue will not flow through the gap below 4um, so the electrical safety characteristics of the welding process are guaranteed.
With mobile phones, computers and other portable electronic products, increasingly thin, miniaturization, high performance, IC packaging is also increasingly miniaturized, high aggregation, CSP/BGA rapid popularization and application, CSP/BGA packaging process operation requirements are also getting higher and higher. The role of underfill is also increasingly valued.
BGA and CSP are fixed on the circuit board through fine solder balls. If they are affected by external forces such as impact and bending, the welding parts are prone to fracture. The bottom filling adhesive is characterized by rapid movement and rapid curing, which can quickly penetrate into the bottom of BGA and CSP and has excellent filling performance. After curing, it can relieve temperature shock and absorb internal stress, strengthen the connection between BGA and substrate, and thus greatly enhance the reliability of the connection.
For example, the mobile phone we use every day can still operate normally when it is turned on from a height of 2 meters. It has no effect on the performance of the mobile phone, but the shell is scratched a little. It's amazing, isn't it? This is because the BGA underfill is applied to fill the BGA/CSP to make it more firmly bonded to the PBC board.