PCB Strip Scale Numerical Study on Vacuum Molded Underfill Void Entrapment in FC-POP Devices

Lee, Moon Soo; Baick, In Hak; Lee, Minwoo; Kim, Byungwook; Lee, Miji; Kang, Hyung Seok; Kim, Jinseok; Rhee, Hyug-Gyo; Pae, Sangwoo

doi:10.1109/iirw47491.2019.8989917

Cited by 2 publications

(1 citation statement)

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“…The incomplete filling or voiding is the main problem in the underfill process [10]. The void in the package could induce unintended problems such as the pop-corn phenomenon and solder extrusion [11] during the reflow soldering process. Many attempts have been made to minimize and eliminate the void defects.…”

Section: Introductionmentioning

confidence: 99%

Package-on-Package (Pop) Underfill Process Using a Material Dam Method

Ali

Khor²,

Azmi³

et al. 2022

AEJ

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Recent developments in the electronics industry have introduced a multi-stack ball grid array (BGA) to meet the growing consumer demand for both high-performance and smaller-sized chip packages. This study focused on the preliminary study of the Package-on-Package (PoP) underfill process using a material dam method. High viscosity type of underfill material is considered for the underfill process. In the current experimental work, L path-dispensing method was chosen due to its advantages, as reported in the previous work. The material dam method was used to prevent underfill from moving backwards and flowing out from the dispensing region. The material dam was built surrounding the PoP package. The effectiveness of the underfill process was analyzed based on the cycle time and lateral lapping, which are significant factors in material selection. The experimental results revealed that slow underfill flow may cause the quickly harden of material while the dispensing process is still running. This situation restricts the underfill flow and creates voids in the PoP package. The material dam method successfully enhanced the underfilling process for layers 3 and 4 stacked-package. This study is expected to provide the preliminary underfill process of stacking the PoP package and is useful as a reference for the engineer in the microelectronics industry.

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Section: Introductionmentioning

confidence: 99%