Multilayer PCB Circuit

1-2 days. We have our own warehouse and stock in large quantities.

Yes. Outer layers(L1/L4) copper weight and inner layer copper can be different, but it requires careful design to avoid compromising structural integrity. What needs to be highlighted is that the asymmetrical distribution can lead to warping caused by uneven thermal expansion. To avoid such a situation, we will add balanced copper or adjust prepreg and core thicknesses to compensate. Common mixing copper can be: thicker copper(2oz or more), for power and ground layers, and thinner copper(5 oz- 1 oz) for signal layers.

Typical smartphone PCBs can use 6-12 layers depending on complexity. Compact smartphones include CPISs, wireless charging, and multiple cameras in a tiny space, which requires high-density interconnects for more connections. More layers enable denser components, better signal integrity, and greater heat dissipation, while keeping the phone thin.

Key challenges in multilayer PCB manufacturing include 1. precise layer alignment. The multiple layers increase the alignment difficulty; 2. Internal circuit production. A multilayer of lines may cause leakage of the inner layer and influence etching and curling; 3. high-quality via formation. Thick laminate increases the difficulty of roughness and decontamination and may cause drill breakage during drilling. 4. Thermal management. High layer counts are more likely to have resin starvation or Z-axis expansion issues.

We don’t recommend the odd-layer PCB because they are easier to warping during manufacturing due to uneven copper distribution. On the contrary, the copper of even stack-up PCBs is systematically distributed, which prevents thermal stress and mechanical bending. If you want to customize 3 or other odd PCBs, they need to add extra prepreg or adhesive layer to balance the stack, which makes the circuit more complex and results in a higher cost.

Yes. It saves time, but we still need to confirm the material inconsistencies, your design requirements, and manufacturing limitations to ensure the best performance.

Copper roughness impacts signal loss and impedance variations. Rough copper increases resistance and insertion loss, causing skin effect. Rougher copper can also alter effective Dk, leading to impedance deviations.

Moisture absorption and thermal stress are two major reasons. For prevention, workers may preback before assembly, use high-Tg materials, and optimize lamination pressure, control lamination processes.