The process difficulties in manufacturing micro via hole PCBS mainly lie in the following aspects:
Drilling accuracy and drill bit durability:
Micro via holes usually have extremely small diameters (such as 0.1mm or even smaller), which poses extremely high requirements for drilling accuracy. Traditional mechanical drilling technology relies on high-speed rotating drill bits. When the hole diameter approaches or is less than 0.1mm, the rigidity, stability and durability of the drill bit become huge challenges. Tiny drill bits are highly prone to bending or breaking, which affects the accuracy and efficiency of drilling.
Difficulty of material processing
The substrate materials of PCBS are mostly composite materials such as glass fiber reinforced resin (FR-4), which are prone to problems such as delamination and burrs when processed by extremely fine drill bits. Especially for ultra-thin plates or materials with a high TG (glass transition temperature), the processing difficulty is greater and more precise process control is required.
Hole wall quality and uniformity of copper plating:
The quality of the hole walls of micro-VIA holes directly affects the subsequent electroplating and welding processes. The hole walls need to be smooth and free of burrs, and the copper plating layer should be uniform and free of voids to ensure good electrical conductivity and mechanical strength. However, due to the small pore size and large depth of micro-VIA holes, problems such as uneven coating and voids are prone to occur during the copper plating process.
Hole plugging and solder mask process
Micro-via holes need to be filled during the manufacturing process to prevent tin penetration or flux residue during wave soldering. However, due to the extremely small hole diameter, the hole-filling process is rather difficult, and problems such as incomplete hole-filling and ink climbing to the surface of the pad are prone to occur, which affects the welding quality and reliability.
Cost and Production Efficiency
Achieving high-precision manufacturing of micro-VIA holes requires high-end equipment, precise tools and strict quality control processes, which undoubtedly will significantly increase production costs. Meanwhile, due to the complex process and low yield rate, the production efficiency has also been affected to a certain extent.
