Wrap Plating Capabilities for Printed Circuit Boards
Defined by IPC Standard IPC-6012B Amendment 1

NetVia Group is at the forefront of technological advancements in the printed circuit board (PCB) industry, offering state-of-the-art wrap plating capabilities that adhere to the stringent requirements of the IPC-6012B standard. Our commitment to excellence and innovation ensures that our customers receive superior products that meet the highest industry standards.

Understanding Wrap Plating

Wrap plating is a crucial process in the manufacturing of rigid printed circuit boards, particularly in high-reliability applications such as electronics manufacturing. It involves plating copper on through-hole walls that extend over the top and bottom edges of the board, creating robust electrical connections between layers. The IPC-6012B specification outlines the requirements and performance criteria for rigid printed boards, including detailed guidelines for wrap plating. This guide provides an overview of wrap plating specifications, required testing, specialized equipment, and key parameters that customers need to define when specifying wrap plating for their PCBs.

IPC-6012B Amendment 1

The IPC-6012B Amendment 1 standard outlines the performance and quality requirements for rigid PCBs. This amendment includes specific guidelines for wrap plating, ensuring consistency and reliability across the industry. By adhering to this standard, The Nevia Group guarantees that our wrap plating processes meet or exceed the stringent criteria set by the IPC.

IPC-6012B specifies the following requirements for wrap plating:

• Plating Thickness: A minimum copper thickness of typically 0.0008 inches (20 microns) is required to ensure adequate conductivity and mechanical strength.
• Coverage: Complete coverage of the edge of the through-holes and extension onto the outer layers is necessary to provide a continuous conductive path.
• Adhesion: Copper must adhere well to the substrate without peeling or delamination.
• Uniformity: The wrap plating should be uniform in thickness around the circumference of the plated hole to avoid weak spots.
• Defect Criteria: Acceptable and unacceptable defects, such as voids, cracks, or inclusions, are defined in the specification.
• Testing: Boards should undergo specific tests for plating adhesion, continuity, and overall quality to confirm they meet the required standards.

Our Wrap Plating Capabilities

At Nevia Group, we leverage cutting-edge technology and advanced techniques to deliver exceptional wrap-plating services. Our capabilities include:

Copper Wrap Plating Structures

Filled via-in-pad structures are essential for routing signals between layers in a multilayer PCB, requiring the via holes to be copper-plated. This plating connects to other pads within the via-in-pad structures and directly to a trace via a small annular ring. While these structures are crucial, they can experience reliability issues under repeated thermal cycling.

The IPC 6012E standard has recently introduced a copper wrap plating requirement for via-in-pad structures. This specification mandates that the filled copper plating should wrap around the edge of the via hole and extend onto the annular ring surrounding the via pad. This enhancement improves the reliability of the via plating and helps reduce failures caused by cracks or separation between surface features and the plated via hole.

High-Precision Plating

We utilize state-of-the-art equipment to achieve high-precision wrap plating. Our technology ensures uniform thickness and coverage, minimizing the risk of defects and ensuring optimal electrical performance. This precision is crucial for high-density interconnect (HDI) boards and other advanced applications.

Processing Steps

The most common process for copper wrap plating involves panel plating the hole walls and surface simultaneously. During this step, the surface copper must exceed the minimum required thickness for wrap plating to accommodate the subsequent planarization process. A selective barrel plating technique is then used to further plate the hole walls to meet the customer’s specifications. After selective barrel plating, the vias are filled and planarized to remove excess via fill material and any raised areas around the filled holes, achieving a flat copper surface.

This process is carefully controlled to ensure that enough copper remains on the panel surface to meet the minimum wrap plating thickness specified in IPC-6012B, Table 3.2. Destructive cross-section analysis is required to verify that the wrap thickness meets these standards. Additional wrap plating cycles will increase the overall surface copper thickness using this method.

Common Problems You See with PCBs Using Wrap-Plating Method

• Inadequate Copper Thickness: Copper plating may not meet the required thickness specifications, leading to insufficient conductivity and mechanical strength.
• Non-Uniform Plating: Uneven copper wrap plating around the via holes can result in inconsistent electrical and mechanical properties.
• Voids and Air Bubbles: Voids or air bubbles within the wrap plating can create weak spots or lead to failure.
• Plating Cracks and Delamination: Cracks or separation between the copper plating and the substrate can occur due to thermal stress or poor adhesion.
• Inadequate Adhesion: Poor adhesion of the wrap plating to the via walls or surface can result in peeling or delamination.
• Excessive Plated Bumps: Excess copper around filled vias can create raised areas that interfere with subsequent processes or components.
• Insufficient Planarization: Inadequate planarization after via filling can leave bumps or uneven surfaces that affect the circuit boards flatness.

Applications of Our Wrap Plated PCBs

Our wrap-plated PCBs are used in a wide range of applications, including:

Aerospace and Defense

In aerospace and defense applications, reliability and performance are critical. Our wrap-plated PCBs provide the robust electrical connections and mechanical strength needed to withstand the demanding conditions of these industries.

Medical Devices

Medical devices require precise and reliable PCBs. Our wrap plating capabilities ensure that our PCBs meet the stringent requirements of the medical industry, providing reliable performance in life-saving applications.

Telecommunications

The telecommunications industry relies on high-performance PCBs for signal integrity and reliability. Our wrap-plated PCBs deliver the electrical performance needed for advanced telecommunications equipment.