What is the Process of Multilayer PCB Manufacturing

Multilayer PCB
What is the Process of Multilayer PCB Manufacturing

The printed circuit boards (PCBs) are one of the most important parts of electronic circuits and contribute to their performance. Certainly, along with the operations of PCBs, it becomes important to understand their manufacturing process as well. Since 60% of PCBs used in the industrial electronic circuits are multilayered, the manufacturing process of multilayer PCB becomes a topic of interest. The demand for smaller, powerful, and faster devices has driven the demand for multilayer PCBs. Copper is used as a conductor in these PCBs, which contributes to their current carrying capacity. This post discusses the manufacturing process of multilayer PCBs and also gives insights on the selection of copper multilayer PCB manufacturers.

A Brief Outlook on Multilayer PCB Manufacturing

The manufacturing process followed by copper multilayer PCB manufacturers is quite straightforward in nature. The process of manufacturing proceeds in the following ways:

  • The materials are selected for inner layer core, prepreg sheets, and copper (Cu) foils.
  • The prepreg sheets are made of glass cloth with epoxy resin.
  • The core sheet laminates are further covered with the copper (Cu) foils of specific weight and thickness.
  • These laminates are then covered by photosensitive dry films, which allow the UV light to get in contact with the resist. By utilizing the UV rays, the electronic data of inner circuitry is transferred to the resist.

This is the process of one core laminate preparation but multilayer PCBs are manufactured by multilayer lamination. Let’s discuss the multilayer lamination process, in order to thoroughly understand the multilayer PCB manufacturing process.

Understanding the Multi-Layer Lamination Process

The multilayer lamination of PCB is a sequential process. This means the layering base will be a Cu foil sheet topped up by the layers of prepreg. The number of prepreg layers varies depending on the operational requirements. Further, the inner core is settled on the prepreg layer and then it is further topped up with layers of prepreg covered with Cu foil. This makes one laminate of this multilayer PCB stack. The same laminates are stacked up, one over another. When the final foil is added, it creates the final lamination stack which is referred as a “Book” and each laminate is referred to as “Chapter”.

Once the book is complete, it is then transferred to a hydraulic press. The hydraulic press is heated and exerts a significant amount of pressure and vacuum on the book. The process is called curing as it suppresses the laminates against each other and allows the resin prom prepreg to amalgamate with core and foil. Then the assembly is taken out and cooled at room temperature which allows the resin to settle, and this finalizes the manufacturing of copper multilayer PCB manufacturing.

Although most copper multilayer PCB manufacturers follow the same process, the output is not limited to the process itself. It requires meticulous attention to detail. Therefore, it is essential to partner with the right copper multilayer PCB manufacturer.

How to Choose a Right Multilayer PCB Manufacturer?

There are several factors to consider when choosing the multilayer PC manufacturer for your application. The following points will help you understand it better.

  • Technical Capabilities: This process requires extensive operator training and specific equipment and techniques, which can only be offered by a prominent copper multilayer PCB manufacturer.
  • Experience: It is important to check the experience of the manufacturer before making a decision. This can be easily understood from their online profile or you can confirm them during a discussion phase. You can specifically check the manufacturer’s experience in your industry and the types of projects he has undertaken.
  • Customization Options: Although several electronic devices use PCBs in standard dimensions, many devices also require customized PCBs. So, you need to check if the chosen manufacturer is capable of delivering PCBs in customized specifications.
  • Industry-specific Certifications: This becomes the most important factor if you belong to any critical service industries like medical, military and defense, aerospace and aeronautical, and so on.
Knowing the importance of copper multilayer PCBs, it is necessary that you source them from a trusted manufacturer like Twisted Traces. They have been working with clients across aerospace and satellite, LED, medical, military, electronics, automotive, and telecommunication industries. The company provides copper multilayer PCBs in custom specifications.


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