PCBs or printed circuit boards are an integral part of most electronic and electromechanical devices. They are really the backbone of the part or product in which they are embedded, as the overall functionality of these products depends on the operation, accuracy, and design of these PCBs. Decades ago what started using a single layer PCB has now evolved to multiple layers. This is mainly because of the complex designs and requirements of electronic devices. Also, the shrinking sizes of these devices have made the PCB design and layering very complex with several components mounted on the board. All these layers on the PCB need to be rightly arranged, and this method is called stack-up or stacking of layers on the board.
Why a Proper Stack-up is Required?
PCBs are made of various materials such as metal, glass, fiber, and so on. However, all of them have a copper coating or layer and an insulating layer even if the PCB is single or double layered. Nowadays, most PCBS have multiple layers, and this needs to be embedded in a single part or device. Also, while layering, we do not want to damage any coatings or mounted components. So, stacking of layers needs to be organized. While the bottom most layer is insulated, all the other layers are interconnected. Here are a few reasons why layer stacking is important:
- It enhances the overall device functionality and increases the speed of processing.
- Proper layering works like a protective layer and eliminates external noise, crosstalk, radiation, or other interferences within the layers.
- A properly stacked up board reduces the overall product cost as it helps make the board compact by placing a good amount of components and circuits on just one board.
- It also easier for a well-stacked board to be fitted into the device and packaged well to be shipped out. So, it also helps reduce the packaging costs.
What Capabilities Should You Look for in Your PCB Services Provider?
When partnering with a PCB services provider, look for someone who offers end-to-end solutions. Also they must be able to understand your application requirements and advise accordingly in terms of PCB material selection, number of layers, design, assembly, and so on. Here are a few pointers which may help especially when you need a multilayered stack-up.
- The manufacturer must stick to the same PCB materials for core and prepreg layers.
- Check if the manufacturer uses rivet-and-dowel or any other effective method for stacking. This helps prevent offsetting the layers.
- The manufacturer may use an epoxy plate as a padding material when stacking the boards together as this prevents measling by balancing the pressure.
- Sit with the manufacturer and decide upon the number of layers you need depending upon your circuit and board size.
- The manufacturer must check for any leaks and emissions in the design stage.
- The layers may range from 2 to 10 or even more depending upon the device requirements and accordingly the design complexity.
- PCBs with two or more layers have interconnects on each side. For each board there are three layers- copper coating on the top layer, copper coating on the bottom layer, and a laminate core in between to separate the top and bottom layers. This is the base you must know when working with a PCB services provider.
- As the number of stacks go on increasing to 4, 6, 8, 10, or more, so do the number of layers although top and bottom layers and the laminate core remain the same. For instance, for a 4-layer board, aside from these three layers, there are two prepreg and two inner layers on each side of the laminate core.
- In a 6-layer board, aside from the above layers, ground layer on the top side and power layer on the bottom side are added. Also there are route layers on each side and two core layers.
- The manufacturer or service provider would guide you as to how many layers you would require and the materials you must use among other factors.
If you are looking to incorporating PCBs in your products, it is best to partner with a reliable PCB manufacturer and assembly service provider. Look for players such as Rigiflex who offer customized and end-to-end PCB solutions. Also, they have advanced PCB stack-up capabilities and have been in the market for more than two decades.