The embedded resistor and capacitor process is a process for embedding resistors and capacitors within a PCB. Typically, resistors and capacitors on PCBs are soldered directly to the board surface using surface mount technology. However, the embedded resistor and capacitor process embeds the resistors and capacitors within the internal layers of the PCB. This printed circuit board (PCB) consists, from bottom to top, of a first dielectric layer, a buried resistor, a circuit layer, and a second dielectric layer. The portion of the buried resistor not covered by the circuit layer is covered with a polymer isolation layer. This polymer isolation layer has a roughened surface, with a surface roughness Rz greater than 0.01μm, and a thickness of at least 0.1μm at the corners.

This new printed circuit board (PCB) features a polymer isolation layer covering the surface of the buried resistor, protecting it from chemical corrosion during subsequent wet processes such as browning and super-roughening. This improves the manufacturing process for buried resistors and further promotes their application in inner layers.

The advantages of embedded resistor and capacitor technology include:

1. Space Saving:

Because resistors and capacitors are embedded directly into the internal layers of the board, PCB space can be saved, making the entire circuit board more compact.

2. Reduced Circuit Noise:

Burying resistors and capacitors into the internal layers of the board reduces electromagnetic interference and noise, improving circuit stability and anti-interference capabilities.

3. Improved Signal Integrity:

The embedded resistor and capacitor technology can reduce signal transmission delay and reflection loss, improving signal transmission integrity and reliability.

4. Reduced PCB Thickness:

Because resistors and capacitors are embedded into the internal layers of the board, the thickness of the PCB can be reduced, making the entire circuit board thinner and lighter.

However, the embedded resistor and capacitor technology is relatively complex in manufacturing and maintenance, as the resistors and capacitors cannot be directly inspected or replaced. Furthermore, the embedded resistor and capacitor technology is typically used in high-end electronic products and is relatively expensive.

When it comes to high-density circuit designs, the embedded resistor and capacitor technology becomes a very useful technology. In traditional PCB layouts, resistors and capacitors are typically soldered onto the PCB surface as surface mount components. However, this layout method results in a larger PCB footprint and can potentially introduce noise and interference.

The embedded resistor and capacitor process addresses these issues by embedding resistors and capacitors directly into the internal layers of the PCB.

The following are the detailed steps for this process:

1. Fabricating Internal Layers:

During PCB fabrication, in addition to the conventional layers (such as outer and inner layers), separate internal layers are created specifically for embedding resistors and capacitors. These internal layers contain areas for embedding resistors and capacitors. These layers are typically fabricated using the same techniques used in conventional PCB manufacturing, such as plating and etching.

2. Resistor/Capacitor Encapsulation:

In the embedded resistor and capacitor process, resistors and capacitors are encapsulated in specialized packages to facilitate embedding into the internal layers of the PCB. These packages are typically thin to accommodate the thickness of the PCB and provide good thermal conductivity.

3. Embedded Resistors/Capacitors:

During the internal layer fabrication process, embedded resistors and capacitors are embedded within the PCB's internal layers. This can be achieved through various methods, such as using specialized pressing techniques to embed the resistors and capacitors between the internal layer materials, or using laser technology to etch cavities in the internal layer materials and then fill them with the resistors and capacitors.

4. Connecting Layers:

After the internal layers containing embedded resistors and capacitors are completed, they are connected to other conventional layers (such as the outer layers). This can be achieved through standard PCB manufacturing techniques (such as lamination and drilling).

Overall, embedded resistors and capacitors are a highly integrated technology that embeds resistors and capacitors within the internal layers of a PCB. It saves space, reduces noise, improves signal integrity, and enables thinner and lighter PCBs. However, due to the complexity and increased cost of manufacturing and maintenance, embedded resistors and capacitors are typically used in high-end electronic products with high performance requirements.