Can a Circuit Board Stiffener Help Prevent the Delamination of PCB Layers?
Circuit Board Stiffener Help Prevent the Delamination of PCB Layers
A printed circuit board (PCB) carries all of the electrical and mechanical components that make up an electronic device. It is composed of multiple layers of insulating and conducting materials, each bonded together with heat and pressure. A conductive copper layer is then etched onto the insulating layers, forming the necessary pattern of conductors. When handled roughly, a PCB can suffer from delamination, which is the breaking apart of the copper-epoxy composite conductor layers. This can be very costly to fix. A circuit board stiffener can help prevent the delamination of PCB layers, but it is essential to use proper handling techniques and understand how to spot the signs of damage before they become a serious problem.
A stiffener is an additional component attached to a flexible circuit board to provide support and rigidity. The flex PCB stiffener is usually made from polyimide or glass-filled epoxy material, and is coated with a non-conductive material to prevent shorting between the conductive traces on the flex circuit board and any metal component on its surface. The circuit board stiffener is typically attached to the flex PCB using thermal bonding or pressure sensitive adhesive, making it easier to remove and replace should any issues arise.
During fabrication, a flex PCB is subjected to extreme thermal, electromagnetic and vibratory stress, which can damage the conductive copper layers. This damage is often caused by a mismatch between the coefficients of expansion of the constitutive layers of the multilayer PCB and the underlying laminate. Stiffeners can help to mitigate these problems by restricting flexibility in specific areas of the flex circuit that are earmarked for soldering connections.
Can a Circuit Board Stiffener Help Prevent the Delamination of PCB Layers?
In addition to preventing delamination, the stiffener also helps to dampen vibrations and resonance, enhancing signal integrity and decreasing interference. This is especially important for flex circuit boards that are used in harsh environments.
The most common type of flex PCB stiffener is FR-4, which is a high-temperature-tolerant polyimide film that is glued to the flex circuit board using a thermally-curing epoxy. Alternatively, aluminum and stainless steel stiffeners can be used for projects that require extra stiffness and heat sinking properties.
PCB stiffeners can be added to any flex circuit board, but they are particularly useful for projects that involve plated through hole components and/or surface mount components. In these situations, the stiffeners are needed to keep the plated holes and components from bending too far during assembly, which could cause the metal to break away from the PCB and leave it unusable. Stiffeners can also be used to keep the plated holes and other surface-mount components from contacting one another if the flex circuit board is bent or suspended, which would create large sag areas.
It is important to consider the size and weight of your flex PCB when selecting a stiffener, as the more bulky stiffeners will add more thickness and weight to the flex circuit board. This can make it more difficult to handle and may affect the flex PCB’s performance.