PCB Copper Clad Laminate Problems and Countermeasures (1)

1. To be able to search and find

It is impossible to manufacture any number of PCBs without encountering some problems, mainly due to the material of the PCB copper clad laminate. When quality problems arise during the actual manufacturing process, it also appears that the PCB substrate material is often the cause of the problem. Even a carefully written and well-executed PCB laminate specification does not specify the tests that must be performed to determine if a PCB laminate is the cause of a production process problem. Listed here are some of the most commonly encountered PCB laminate problems and how to identify them.

Once you encounter a PCB laminate problem, you should consider adding it to the PCB laminate specification. Often, without this specification enrichment work, there will be constant quality changes and consequent product obsolescence.

Usually, material problems due to variations in the quality of PCB laminates occur in products manufactured by manufacturers using different batches of raw materials or using different pressing loads. Few users hold large enough records to be able to distinguish a particular pressing load or batch of material at the processing facility. So it often happens that PCBs are constantly being produced and loaded with components, and warping is continuously created in the solder baths, wasting a lot of labor and expensive components.

If the batch number of the loading can be checked immediately, the PCB laminate manufacturer can check the batch number of the resin, the batch number of the copper foil, the curing cycle, etc. That is, if the user fails to provide continuity with the PCB laminate manufacturer’s quality control system, the user suffers long-term losses. The following describes general issues related to substrate materials in the PCB manufacturing process.

2. Surface Problems

Signs:
Poor adhesion of printing material, poor adhesion of coating, some parts cannot be etched away, and some parts cannot be soldered.

Applicable Inspection Methods:
Visual inspection is usually performed by forming visible water marks on the surface of the board.

Possible Reasons:
Because of the very dense and smooth surface caused by the release film, the uncoated surface is too bright. Typically on the uncopper side of the laminate, the laminate manufacturer does not remove the release agent. Pinholes in the copper foil, causing the resin to flow out and accumulate on the surface of the copper foil, which usually occurs on copper foils thinner than the 3/4 ounce weight gauge. Copper foil manufacturers apply excess antioxidants to the surface of the copper foil. Laminate manufacturers have changed resin systems, release sheets, or brushing methods.

There are many fingerprints or grease stains due to improper operation. Get oil on during punching, blanking or drilling operations.

Possible Solutions:
Laminate manufacturers are advised to use fabric-like films or other release materials. Contact the laminate manufacturer to use mechanical or chemical removal methods. Contact the laminate manufacturer to inspect each batch of copper foil that fails; ask for a recommended solution for resin removal. Ask the laminate manufacturer for removal methods. Hydrochloric acid is usually recommended, followed by mechanical scrubbing. Work with the laminate manufacturer and specify user test items before making any changes to the laminate manufacturing.

Educate personnel in all processes to wear gloves to handle copper clad laminates. Make sure that the laminate is shipped with the proper liner or bagged, the liner is low in sulphur, the bag is free of dirt, and care is taken to ensure that no one is touching it while using a silicone-containing detergent copper foil, degreased all laminates prior to plating or graphic transfer process.