Surface mount component package category

The package structure of SMD components is the basis of process design. According to the structure of pins or solder joints, it can be divided into: Chip type J-shaped pin type, L-shaped pin type, BGA type, BTC type, castle type. The electrodes of the surface-assembled components are soldered ends, and some are pins, which can be collectively referred to as electrodes.

1.Chip package

A. Chip resistor

The chip resistance welding end plating layer is generally three layers, that is, the bottom layer of Ag or Ag-Cr/Ni/sn.

B. Chip capacitor

The chip capacitor solder end plating is generally three layers, that is, the bottom layer Ag or Cu/Ni/Sn. The bottom layer plating depends on the internal electrode plating. If the internal electrode is Pa or Pd-Ag, the bottom plating layer select Ag: if the internal electrode coating is Ni or Cu, and the bottom coating is Cu.

2.SOP, QFP package

The SOPOFP package is a leaded package. The lead frame is mostly made of copper alloy or iron-nickel alloy. The lead plating is usually a three-layer structure.

3.BGA package

BGA-type solder balls use alloys that are consistent with common solders. Currently, they are mainly SAC alloys such as SAC305 and SAC405.

4.QFN package

The QFN package lead frame material is generally copper, and there are various kinds of soldering end plating, mainly based on the process of the internal electrode. 0.4mm pitch and below, the coating is NiPdAu; the spacing is larger than 0.4mm. Using Sn or Sn-Ag.

5. Plug-in package

Plug-in package leads mainly use Sn, Sn-Bi, Sn-Ag-Cu and Ni-Sn.

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