In typical scenarios, resistors and capacitors are directly soldered onto the surface of a PCB. However, the embedded resistor and capacitor process involves embedding these components within the internal layers of the PCB. A PCB using this technology consists of layers from bottom to top: the first dielectric layer, embedded resistors, signal trace layer, and the second dielectric layer. The section of the embedded resistors without a signal trace layer is covered by a polymer isolation layer, which is intentionally roughened to a surface roughness (Rz) greater than 0.01 μm. The polymer isolation layer at the corners has a minimum thickness of 0.1 μm.

The benefits of the embedded resistor and capacitor process include:

Space-saving:

By embedding resistors and capacitors directly into the internal layers of the PCB, it is possible to save valuable surface space, resulting in a more compact overall design.

Reduced circuit noise:

Embedding resistors and capacitors within the internal layers can help minimize electromagnetic interference and noise, leading to improved circuit stability and enhanced resistance to external interference.

Improved signal integrity:

This process helps reduce signal transmission delays and reflection losses, which in turn improves the integrity and reliability of signal transmission.

Thinner PCB:

With resistors and capacitors integrated into the internal layers, the PCB can be made thinner and lighter, offering a more streamlined design.

 

However, the embedded resistor and capacitor process can be relatively complex to manufacture and maintain, as these components cannot be easily accessed or replaced. Additionally, this method is typically used in high-end electronic products, which results in higher production costs.

In high-density circuit designs, embedded resistor and capacitor technology is particularly advantageous. In conventional PCB layouts, surface-mounted resistors and capacitors can increase the PCB footprint and introduce potential issues with surface-related noise and interference.

The embedded resistor and capacitor process effectively addresses these challenges by embedding the components within the internal layers of the PCB.

 

Here are the detailed steps involved in the PCB embedded resistor and capacitor process:

Internal Layer Fabrication:

During PCB production, specialized internal layers are created specifically for the embedded resistor and capacitor components, in addition to the conventional outer and inner layers. These internal layers are designed to accommodate the areas where the resistors and capacitors will be embedded. The fabrication process for these layers typically involves techniques such as plating and etching, similar to standard PCB manufacturing.

Resistor/Capacitor Package:

In the embedded process, resistors and capacitors are packaged in specialized forms that are designed for integration within the PCB’s internal layers. These packages are typically thin to match the PCB’s thickness and are engineered to provide good thermal conductivity.

Embedding Resistors/Capacitors:

During internal layer fabrication, the resistors and capacitors are embedded into the PCB’s internal layers. This can be achieved using techniques such as specialized compression methods to position them between layer materials, or laser technology to etch voids in the internal layer material, followed by filling these voids with the resistors and capacitors.

Connection Layers:

Once the embedded resistors and capacitors are integrated into the internal layers, these layers are connected to other standard layers (such as outer layers). This connection is typically accomplished using conventional PCB manufacturing methods like lamination and drilling.

 

In summary, the embedded resistor and capacitor process is an advanced integration technology that embeds resistors and capacitors within a PCB’s internal layers. This approach offers space savings, reduces noise, improves signal integrity, and results in a thinner, more lightweight PCB. However, due to the complexity of manufacturing and maintenance, as well as the increased cost, this process is generally used in high-end electronic products that demand superior performance.

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