Everyone knows that multi-layer circuit boards rely on vias for conductive connections, but how do the vias conduct
1、 Sinking copper

2、 Copper deposition, also known as chemical copper deposition, is mainly based on the displacement reaction in chemistry to deposit a layer of copper on the hole wall as a conductive lead for subsequent copper electroplating. If it is a conventional thin copper, its thickness is generally around 0.5 μ m. As the most traditional pre electroplating copper preparation process, it has the following advantages and disadvantages:

3、 Advantages:

(1) Copper metal has excellent conductivity (copper wire is commonly used as the conductor in wires);

(2) The thickness can be adjusted within a wide range and has a wide adaptability (currently the lowest in the industry is around 0.3 μ m, and the highest can reach 30 μ m, directly replacing the subsequent electroplating copper process);

(3) The process is mature and stable, and can be applied to all types of circuit board products (PCB/FPC/RFPCB/carrier board/metal substrate/ceramic substrate, etc.).

Disadvantages:

(1) Containing formaldehyde, which is harmful to the health of operators;

(2) Large equipment investment, high production costs, and significant environmental pollution;

(3) The time control is short, with a general effective time of 3-6 hours.

2、 Black hole

Black hole is a type of direct electroplating technology, which mainly uses physical principles to adsorb carbon powder on the surface of the hole wall, forming a conductive layer as a conductive lead for subsequent copper electroplating. Normally, its thickness is 0.5-1 μ m. As one of the mainstream pre electroplating copper preparation processes, it has the following advantages and disadvantages:

advantage:

(1) Free of formaldehyde, with minimal impact on the health of workers and minimal pollution to the environment;

(2) The equipment investment is not large, the waste treatment is simpler, and the process cost is lower than that of copper deposition;

(3) The medication and process are relatively reduced, and the timeliness can reach 48 hours, making it easier to maintain and manage.

Disadvantages: (1) In terms of conductivity, conductive carbon powder is weaker than deposited copper layers;

(2) Its applicability is not as wide as that of copper deposition. Therefore, although it has been widely used, it is currently mainly used in the industry for double-sided panels, and high-end products such as HDI are almost not adopted