The Underfill Encapsulation analysis is used to analyze the flow of the encapsulant material in the cavity, between the chip and the substrate during the underfill encapsulation process.
A weakness in the flip chip process is the solders that typically connect the chip to the board. During service, the solders can be damaged, mainly from the stresses associated with the temperature change of the package.
In most cases, underfill encapsulation is done by dispensing the encapsulant material along the periphery of the chip. Capillary force drives the encapsulant through the space between the chip and the board.
During Underfill Encapsulation, each injection location is open at a different time because of the time delay when the dispensing head moves around the edge of the chip for the dispensing. It is often common to find that dispensing is done over several passes to avoid excessive spreading of encapsulant in the dispensing area when a large amount of encapsulant is dispensed all at once. This is known as dynamic dispensing. The Dynamic Dispensing analysis option in the Process Settings Wizard enables you to simulate this situation.
The following table shows the available analysis technologies for an Underfill Encapsulation analysis.
There are modeling guidelines for an Underfill Encapsulation analysis.
In order to take advantage of dynamic dispensing for underfill encapsulation, there are several requirements that need to be considered.
The dispensing location is the point where the encapsulant is dispensed for the underfill encapsulation process.
There are different shape factor methods that you can use for an Underfill Encapsulation analysis, depending on whether the region is modeled away from the solders or near the solders in the model.
Underfill encapsulant materials have certain properties.