Shenzhen VIASION Electronic Technology Co., Ltd. has its own SMT chip factory, which can provide SMT chip processing services for 0201 components in the smallest package, and supports various processing forms such as processing with materials and OEM materials. The incoming inspection of SMT chip processing is a very important process, which is directly related to the quality of the PCBA board. Next, I will introduce to you what are the main inspections of the incoming inspection of SMT chip processing.
1. What is incoming inspection for SMT patch processing?
Incoming material inspection before SMT chip processing is the primary condition to ensure the quality of the chip. The quality of components, PCB boards, and SMT chip processing materials directly affect the quality of the PCB board. Therefore, for the electrical performance parameters of the components and the solderability of the soldering tips and pins, the productivity design of the PCB and the solderability of the pads, solder paste, patch glue, stick solder, flux, cleaning agent, etc. The quality of SMT patch processing materials must have a strict incoming inspection and management system. The quality problems of components, PCB boards, and SMT patch processing materials are difficult or even impossible to solve in the subsequent process.
2. Incoming inspection of SMT chip processing components
The main inspection items of components include: solderability, pin coplanarity and usability, which should be sampled and inspected by the incoming inspection department. To test the solderability of components, stainless steel tweezers can hold the component body and immerse it in a tin pot at 235±5℃ or 230±5℃, and take it out at 2±0.2s or 3±0.5s. Check the soldering condition of the soldering end under a 20 times microscope, and it is required that more than 90% of the soldering end of the component is soldered.
The patch processing workshop can do the following visual inspections:
（1） Visually or with a magnifying glass, check the solder ends or pin surfaces of the components for oxidation or contamination.
（2） The nominal value, specification, model, accuracy, and external dimensions of the components should be consistent with the product process requirements.
（3） The pins of SOT and SOIC cannot be deformed. For multi-lead QFP devices with a lead pitch of less than 0.65mm, the pin coplanarity should be less than 0.1mm (optical inspection by the placement machine).
（4） For products that require cleaning, the mark of the components will not fall off after cleaning, and will not affect the performance and reliability of the components (visual inspection after cleaning).
3. PCB board (PCB) incoming inspection
（1） The PCB land pattern and size, solder mask, screen, and via hole settings should meet the SMT PCB board design requirements. (Example: Check whether the pad spacing is reasonable, whether the screen is printed on the pad, whether the via is made on the pad, etc.).
（2） The external dimensions of the PCB should be consistent, and the external dimensions, positioning holes, and reference marks of the PCB should meet the requirements of the production line equipment.
（3） PCB allowable warpage size:
a. Upward/convex surface: maximum 0.2mm/5Omm length and maximum 0.5mm/the length of the whole PCB.
b. Downward/concave surface: maximum 0.2mm/5Omm length and maximum 1.5mm/the length of the whole PCB.
（4） Check whether the PCB is contaminated or damp.