Differences Between Via-In-PAD and Resin Plugging in PCB Manufacturing

1. Via - In - PAD Via - In - PAD is a key process in PCB manufacturing. It involves creating micro - vias within the pad area on the PCB substrate. By fabricating these micro - structures, the plating solution can penetrate and deposit evenly during subsequent electroplating, ensuring a consistent plating layer formation that enhances critical surface properties like corrosion resistance and wear resistance, which are essential for reliable PCB performance.

2. Resin Plugging Resin Plugging is a defect - remediation process for PCB. It dispenses and cures resin into via holes or surface indentations on the PCB’s metal - clad layers. After resin filling and proper treatment, electroplating is performed to form a plating layer that integrates with the metal surface, mainly used to remedy surface imperfections and ensure the integrity and electrical performance of the PCB part.

3. Differences

3.1 Purpose For Via - In - PAD, the purpose is to enable reliable plating distribution within the pad - via structure, facilitating robust interlayer electrical connections while ensuring uniform plating coverage for subsequent surface finishing. Resin Plugging serves to seal and planarize defective vias or surface flaws, preventing plating solution leakage during electroplating, avoiding short - circuits or plating discontinuities, and ensuring the PCB surface meets flatness requirements for downstream assembly like solder mask application and component mounting.

3.2 Application Scope Via - In - PAD is predominantly applied to PCBs featuring pads with integrated vias, commonly used in high - density interconnect (HDI) boards where miniaturized, pad - centered vias enable dense component routing. Resin Plugging is deployed for non - functional vias (NFVs) or defective via structures that could disrupt the plating and assembly processes. It’s critical for blind vias, buried vias, or vias prone to resin wicking issues, ensuring these problematic areas are rendered electroplating - compatible and surface - mount - ready.

3.3 Processing Method Via - In - PAD process entails precise via drilling within the pad, followed by desmear, activation, and then electroplating, where the plating solution infiltrates the via - pad cavity, with metal ions depositing to build up copper (or other plating metals) and form a continuous conductive path through the via while plating the pad surface simultaneously. Resin Plugging process starts with via cleaning and drying, then dispenses thermosetting or UV - curable resin into the target vias using precision dispensing equipment. After resin curing (through thermal or UV exposure), the PCB undergoes desmear to remove excess resin from the surface, followed by activation and electroplating, where the plated metal adheres to the exposed copper around the resin - plugged vias, forming a seamless plating layer across the board surface. In conclusion, Via - In - PAD and Resin Plugging are two distinct and crucial processes in PCB fabrication. Via - In - PAD focuses on establishing reliable interlayer connections through optimized via - pad plating, while Resin Plugging addresses defect remediation and process compatibility. They are applied in different scenarios based on PCB design requirements, surface conditions, and overall manufacturing process needs, jointly ensuring the quality and functionality of the final PCB product.