2. The surface treatment of the terminals and the solder mask (including ink and covering film) requires improved peel strength and enhanced bonding with the base copper.
3. To meet these requirements, we need a more advanced pre-processing PCB process.
4. Enhancing our technology to boost product yield can provide growth opportunities for profit.
5. High-quality pre-treatment solutions can undoubtedly assist us in achieving this at a lower cost.
Common problems and countermeasures in the production process of PCB hard board and FPB soft board:
1. After dry film or wet film treatment, side corrosion and etching shrinkage often occur in the circuit etching, resulting in insufficient or uneven circuit width. This is usually due to improper selection of dry and wet film materials, inappropriate exposure parameters, and poor performance of the exposure machine. Improper nozzle adjustments during development and etching, unreasonable parameter settings, inappropriate concentration range of chemical solutions, and improper transmission speed may also lead to these issues. However, we often find that after checking the above parameters and related equipment performance, no abnormalities are found. However, in the actual board making process, there may still be issues such as excessive corrosion and circuit board dents. So, what is the fundamental reason behind this?
2. When performing PCB pattern electroplating, PCB, FPC terminal surface treatment (such as immersion gold, electroplating gold, electroplating tin, tin, and other process treatments), we often find that the boards produced have penetration phenomena at the edges of dry or wet films, or at the edges of solder mask. Whether it’s the entire board or certain areas where this phenomenon occurs, it will bring unnecessary waste or defective products, and cause trouble for subsequent processing, even eventually becoming scrap, which is very headache inducing! When investigating the reasons, people usually think of issues with dry film and wet film parameters, as well as material properties; Or there may be problems with the ink used for the hard board, the film used for the solder mask, or problems during printing, pressing, curing, and other stages. Indeed, these places can all cause problems. However, we may also be confused to find that even after checking these steps and resolving the issue, the infiltration phenomenon still exists. Is there a reason for this that we have not yet discovered?
3. The circuit board will undergo tin testing before shipment, and customers will also perform tin soldering during use. Regardless of the stage, there may be phenomena such as tin immersion or soldering bubbles, and even when testing the peel strength of ink with tape, there may be obvious peeling or insufficient peeling strength of the soft board cover film, and uneven peeling strength. This is absolutely unacceptable for customers, especially precision SMT surface mount customers. Once the solder mask shines and peels off during the welding process, it will cause the original components to be unable to be installed accurately, resulting in a large amount of component loss and causing huge work losses to customers. Circuit board manufacturers will also face huge losses, such as deductions, material replenishment, and even losing customers. What aspects do we usually focus on when encountering these problems? We usually analyze whether there are problems with the solder mask (ink, film) materials; Are there any issues during the screen printing, lamination, and curing stages; Is there any problem with the electroplating solution. Therefore, we usually have engineers identify the reasons from these aspects and make improvements. Do we also consider weather factors? Recently, the humidity has been high. Is the board absorbing moisture? After some efforts, both the substrate and barrier layer are prone to moisture absorption, and the problem has been partially solved on the surface. But when this kind of problem happens again unintentionally, what is the reason? The work processes that may have problems have been checked and improved, what else have we not noticed?
In response to the common confusion and problems in the PCB and FPC industries mentioned above, we conducted extensive experiments and research, and ultimately found that the important reasons for issues such as poor wiring, penetration, interlayer peeling, blistering, and insufficient peeling strength are due to the pre-treatment part. This includes dry and wet film pretreatment, solder mask treatment, electroplating pretreatment, and other multi-stage pretreatment parts. Speaking of which, perhaps many people in the industry cannot help but smile. The pre-treatment seems simple, including acid washing, degreasing, and micro etching. Many industry technicians are familiar with the performance, parameters, and even formulas of pre-treatment solutions.
