Understanding The Multilayer PCB Fabrication Process

A huge question for people interested in PCB's (Printed Circuit Boards) are first, what are PCBs made of? The basis of most quality printed circuit boards use FR4, which is a rigid type of fiberglass laminate. Depending on the requirements by a PCB designer, various other materials may be used. This would all have to fit the properties necessary to achieve the end result of course so only rely trusted manufacturers such as JY Electronic Technology Co., Ltd. to handle this for you. There are single layered, double layered and multi-layered PCB's, with each serving specific purposes. We have discussed more about single layer PCB's in another article so what we are specifically talking about here will be PCB multilayer fabrication, as there are issues that if not handled properly, will result in a less than desirable end product.

Single layered boards will reveal the copper layer on one side. With double sided boards, the copper is not exposed. Multilayer PCBs are basically what one would imagine. Layers of boards pressed together.

Proper PCB Multilayer Fabrication

PCB Multilayer Fabrication Process

Since a large part of printed circuit board manufacturing involves multilayered circuit boards, dealing with a factory with the right experience will give the best outcome. Manufacturing these are honestly a straightforward process however the attention to minute details is absolutely necessary to achieve a wonderful product.

Each layer involved needs to align carefully to the drill holes and one must account for the expected pressure which will deform under the extreme heat necessary to press the boards securely. A PCB is loaded up to form a book, with each layer being referred to as a chapter in that book. The unpressed book is then put into a PCB multilayer press, stacked up together and then heated to about 350 degrees, with a constant pressure being applied for about an hour. Skilled operators will know the proper clearance around holes, edges, etc., to account for all of this and lay prepreg accordingly.

PCB Multilayer Design

As mentioned, a lot of the intricacies are determined by the design of the printed circuit board. A bad PCB multi-layer design will cause issues such as an imbalance in the load when pressing multi-layer boards. Twisting or "bow" as it's referred to in the PCB industry are the results of either asymmetrical designs or those that involve layers of varying thickness. Standard builds do not usually have these problems but when a design requires it, be sure the factory you are dealing with understands the nuances required to properly build those. See design mistakes that will impact you here.

While what you have read so far is pretty basic, those who dig even deeper end up wanting to understand the whole manufacturing process. Since this is a technical topic, it's usually best to explain with a video which you can watch here:

While students and hobbyists might be more inclined to know even more details, most people who require a PCB would rather let experts deal with the details. All of are clients are welcome to visit our manufacturing plant to see the real specifics about how this is done. Peruse the rest of our site to learn even more about printed circuit boards.