1. Core Causes of Lead Frame Discoloration Lead frames in semiconductor packaging serve as key components for connection and support. Their surface condition significantly affects device performance and reliability. During the actual production process, lead frames often undergo discoloration due to various factors, which not only affect their appearance but may also damage electrical connections….

Via-in-Pad Technology in Chip Packaging: Definition, Applications, Advantages, and Limitations 1. Definition and Classification of “Via in Pad” “Via in Pad” refers to drilling vias directly on the surface-mount component pads in order to connect to internal PCB traces. The core purpose is to replace traditional fan-out routing or peripheral wiring by creating a direct…

Why QFN Packaging is Widely Preferred in the Chip Industry The semiconductor industry value chain can typically be divided into three core areas: chip packaging and testing, circuit design, and wafer manufacturing, with chip packaging and testing falling into the backend of the industry chain. Among various types of surface mount packaging, QFN (Quad Flat…

QFN Traditional Separation Technology Currently, there are two main methods for separating individual QFN (Quad Flat No-Lead) packages. The first method is milling machine separation, which was widely used in the early stage. However, due to its poor processing quality and low yield rate, this technique has been gradually eliminated. The second method is punch-type…

QFN (Quad Flat No-Lead) Package OverviewQFN is a leadless, surface-mount package available in square or rectangular shapes. It features: DFN (Dual Flat No-Lead) Package CharacteristicsDFN differs from QFN primarily in: Core Differences Between DFN and QFN SEO-Optimized Meta Description:“Learn the key differences between DFN and QFN packages. Compare pad distribution, thermal performance, and applications for…

QFN Package Characteristics QFN (Quad Flat No-Lead) devices adopt a Micro Lead Frame (MLF) copper substrate packaging structure. The lead frame is directly exposed at the package bottom to serve as solder terminals, making QFN a leadless package type. The device outline is usually square or rectangular, with a large exposed thermal pad at the…

1. Impact of Package Size on Solder Joint Reliability NASA simulated deep space environments to study the effect of QFN package size on solder joint reliability under thermal shock conditions. Using Weibull distribution analysis (Figure 7), QFN68 packages and QFN16–44 packages were tested. Results show that larger QFN packages have significantly shorter solder joint lifetimes…

Because the side pads of QFN devices are exposed copper, they are highly prone to oxidation during the singulation process and subsequent storage. This oxidation reduces solderability and often leads to poor solder wicking on the side pads during assembly. Although current electronic assembly standards (such as IPC-A-610 and IPC-7093) do not specify solder wicking…

Typical QFN Package Structures Plastic-molded QFN (Quad Flat No-lead) devices are mainly composed of a copper lead frame carrier, conductive adhesive, bare die, bonding wires, and the molded body. The solder terminals are generally located at the bottom of the package. The terminal surface finish is typically either Sn-plated or NiPdAu-plated, forming the standard structure…

Semiconductor Packaging Terminology Explained 1. Die Attach 2. Wire Bonding 3. Flip Chip Technology 4. Molding 5. Lead Frame 6. Substrate 7. Underfill 8. Die Saw / Dicing 9. Solder Ball 10. Reflow Soldering Material-Related Terminology 11. EMC (Epoxy Molding Compound) 12. Die Attach Adhesive 13. Solder Mask 14. TIM (Thermal Interface Material) 15. Cu…