The usual electronic assembly design tends to be miniaturized, smaller devices, smaller spacing, pins and pads are getting closer and closer, and the existing gaps are getting smaller and smaller, and contaminants may get stuck in the gaps. This means that relatively small particles are assumed to remain between the two pads, potentially causing a short circuit. In the past two years, the demand for cleaning in the electronic assembly industry has become higher and higher, not only for products, but also for environmental protection and human well-being, which has spawned many cleaning equipment suppliers. With solution suppliers, cleaning has also become one of the main contents of technical exchanges and discussions in the electronic assembly industry. PCBA proofing and cleaning can improve the quality of the circuit board, otherwise it will affect the stability of the product. Lingzhuo patch proofing sharing introduces the role of PCBA proofing cleaning:

1. Requirements for conformal paint coatings: Before the surface coating of pcba proofing, the resin residue that has not been removed will cause the delamination or unity of the protective layer; the active agent residue may cause electrochemical migration under the coating, thereby causing the coating Crack prevention maintenance failure. Studies have shown that cleaning can improve the adhesion of the coating by 50%.

2. No-cleaning also requires cleaning: According to the current standard, the term no-cleaning means that from a chemical point of view, the residue on the circuit board is safe. It will not have any effect on the circuit board production line, and can be left in on the circuit board. Corrosion, SIR, electromigration and other special detection methods are mainly used to determine the halogen/halide content and then the safety of the no-clean assembly after assembly.

3. Requirements for appearance and electrical performance: The intuitive impact of pcba proofing pollution is appearance. If it is placed in a high temperature and high humidity environment or used, the residue may absorb moisture and turn white. Due to the widespread use of lead-free chips, micro BGA, chip scale packaging (CSP) and 01005 in components, the distance between components and the circuit board is reduced, the size is reduced, and the assembly density is improved. Given that halides are hiding underneath components that cannot be cleaned, spot cleaning can have disastrous results due to the release of halides.

The intuitive impact of contaminants on pcba proofing is the appearance of pcba proofing. If it is placed or used in a high temperature and humid environment, there may be a phenomenon of moisture absorption and whitening of residues. Due to the extensive use of leadless chips, micro BGAs, chip scale packages (CSPs) and 0201 components in components, the distance between components and circuit boards has been reduced from time to time, board sizes have become smaller, and assembly densities have increased. In fact, suspending localized cleaning may constitute catastrophic results due to halide release, given that the halide is hidden under the component or in the middle of the component that cannot be cleaned at all. This also causes dendrite growth, which can result in short circuits.

Using a no-clean flux with a low solids content will still leave more or less residue. For products with high reliability requirements, no residue or contamination is allowed on the circuit board. With regard to military applications, there is a need to clean electronic assemblies. The assembly of ordinary electronic product pcba proofing must go through the SMT+THT process, during which it must go through wave soldering, reflow soldering, manual soldering and other welding processes. source of assembly contamination. Cleaning is a process of dissolving welding residues. The purpose of cleaning is to extend product life in essence by ensuring good surface resistance and avoiding leakage.