Underfill is a type of epoxy material used to fill the gap between Ball Grid Array (BGA) components and Printed Circuit Boards (PCBs). BGA components are commonly used in electronic devices, and they have a large number of solder balls on the bottom surface that make contact with PCB pads. Under-fill material is dispensed onto the PCB, and it flows into the gaps between the BGA component and the PCB during the curing process.
The purpose of Under-fill is to improve the reliability and durability of electronic devices by strengthening the mechanical bond between the BGA component and the PCB. Under-fill also helps to prevent any damage to the solder balls due to mechanical stress or environmental factors like temperature changes.
There are different types of Under-fill materials available, each with their unique properties and characteristics. Some Under-fill materials are designed to be cured using heat, while others can be cured through UV light exposure. The choice of Under-fill material depends on several factors such as the operating environment of the electronic device, required thermal performance, and cost considerations.

Kingsheng Under-fill Methods

Underfill methods are the techniques used to apply Underfill material to Ball Grid Array (BGA) components on Printed Circuit Boards (PCBs). Here are some common Underfill methods:

Dispensing Method
Capillary Flow Method
Film Method
No-Flow Method

Kingsheng Under-fill Process

Under-fill is an essential process for improving the quality and longevity of electronic devices, especially those that are exposed to harsh environments or high temperatures.


The area around the BGA component is cleaned thoroughly to remove any contaminants that could interfere with bonding.

Capillary Flow

The Under-fill material is then heated to initiate capillary flow, which helps the material to fill all the gaps between the BGA component and the PCB.


The Under-fill material is cured either by heating at a specific temperature or through Ultraviolet (UV) light exposure, which hardens the material and improves its adhesion to the BGA component and the PCB.


After curing, the Under-filled BGA component undergoes inspection to ensure that the Under-fill has been applied uniformly and without any defects.

Kingsheng Under-fill process offers several benefits, such as improved reliability, durability, and thermal performance of electronic devices.

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