Why can't I touch the multilayer circuit board directly with my fingers? What are the serious consequences if you touch the circuit board directly with your hands? In fact, this will lead to the scrapping of multi-layer circuit boards and reduce the reliability of the end user. However, it is inevitable to directly touch the multilayer circuit board by hand during work. Therefore, it is necessary to develop the habit of wearing gloves, which can reduce direct contact with the multilayer circuit board. The hazard of the circuit board. The following editor will lead everyone to understand the reasons, hazards and how to avoid fingerprints that may cause damage to the multilayer circuit board.

  1. Fingerprints: Fingerprints are sweat stains on hands. Its main ingredients are water, inorganic salts, fatty oils and various pollutants, such as cosmetics and skin care products.

  2. The hazards of fingerprints in the manufacturing process of multilayer circuit boards:

  3. Touching the circuit board with bare hands before the solder resist will cause the solder resist to fall, resulting in poor adhesion of the oil, and blistering and falling during the hot air leveling process;

  4. During the process from solder mask to packaging, touching the surface of the multilayer circuit board with bare hands will cause the surface of the circuit board to be dirty and lead to poor solderability or adhesion;

  5. Bare objects touch the circuit board in a short time, which causes a chemical reaction of copper on the surface of the board, which leads to oxidation of the copper surface. After a long time, obvious fingerprints will appear after electroplating, and uneven coating will cause serious defects in the appearance of the product;

  6. The wet film or silk-screen circuit before printing and the surface of the circuit board before lamination have fingerprint grease, which can easily cause the adhesion of the dry/wet film to decrease, and lead to the penetration and separation of the plating during the electroplating process, so gold plating is easy to cause After the solder mask on the surface of the circuit board is completed, the pattern will oxidize the surface of the circuit board and show negative and positive colors.

  If the above phenomenon is not eliminated, it will damage the qualification rate and one-time qualification rate of the multilayer circuit board, resulting in a longer production and processing cycle, a higher rework rate and a lower on-time delivery rate.