RO5880 Thick Gold PCB

In PCB (Printed Circuit Board) manufacturing, thick gold process refers to the deposition of a certain thickness of gold layer on the pads or other specific areas of the PCB to improve soldering performance and protect the copper layer from oxidation. Different thicknesses of the thick gold process has a significant impact on the performance and reliability of the PCB:

Solderability: 

The thickness of the gold layer affects the wettability of the solder on the pads. According to the search results, the thicker the gold layer, the better the ductility of the solder, which helps the solder to better wet the pad, thus improving the quality of the solder. However, too thick a gold layer may result in brittle solder joints, which affects the strength of the solder.

Cost: 

The thickness of the gold layer is directly related to the material cost. A thicker gold layer means a higher amount of gold used, which increases the cost. According to the search result, if the gold layer is too thick when plating gold fingers, it not only costs more, but also may lead to brittle solder joints.

Reliability: 

The thickness of the gold layer also affects the long-term reliability of the PCB. Search results indicate that when the gold content in the solder is higher than 3%, the solder joints may become brittle, which in turn affects the mechanical strength and reliability of the solder joints.

Process Control: 

According to the search results, the control parameters of the thick gold process have a significant impact on the quality of the COB (Chip On Board) board beating line. Proper gold thickness ensures stability and consistency of the wire bonding process.

Service Life and Maintenance: 

The search results mention that the thickness of the cover layer (including the gold layer) should be between 1.5-3um to ensure the stability of the PCB for long-term use and ease of maintenance.

Compatibility Issues: 

With the development of lead-free soldering technology, the immersion gold process needs to adapt to higher peak soldering temperatures, which may bring about compatibility issues such as pad non-wetting problems. The search results discuss methods for analyzing immersion gold PCB pad non-wetting issues.

Nickel Layer Influence: 

The nickel layer under the gold layer also has an important influence on soldering results. The thickness and phosphorus content of the nickel layer affects solderability by influencing the formation of intermetallic compounds (IMC). The search results emphasize the influence of the phosphorus content of the nickel layer on wetting performance and reliability.

Nickel Corrosion: 

The corrosion of the nickel layer also affects the wettability of the pad. Severe nickel corrosion can lead to broken solder joints, as described in the search results.

Environmental Adaptability: 

A thick gold layer can improve the PCB's environmental adaptability, especially in harsh environments, where the gold layer protects the copper layer from corrosion and extends the life of the PCB.

Signal Transmission: 

The thickness of the gold layer has less impact on signal transmission because the signal is mainly transmitted in the copper layer. However, an excessively thick gold layer may have a small negative impact on signal transmission.

Repair and Rework: 

Thick gold layers may make repair and rework more difficult because it is more difficult to remove the gold layer than other metal layers.

Aesthetics: 

A gold layer can provide a good appearance, making the PCB look more high-end and professional, which is important for certain applications.

Thermal Cycling Performance: 

Thick gold layers may affect the PCB's performance in thermal cycling tests as the coefficient of thermal expansion of the gold layer is different from that of the copper layer, which may lead to fatigue of the solder joints.

Environmental Regulations: 

As environmental regulations become more stringent, the use of gold as a surface treatment material may be limited because gold is a rare metal that is more expensive to recycle and reuse.

Process Maturity: 

Different thicknesses of gold layers require different levels of maturity in the production process. Thicker gold layers may require finer process control to ensure quality and consistency.

Market Positioning: 

The use of the thick gold process also depends on the market positioning of the product. For high-end products, the use of thick gold process can improve the added value and competitiveness of the product.

The thick gold process for PCBs is a multi-factor decision-making process that requires comprehensive consideration based on specific application needs, cost budgets, process capabilities, environmental requirements, and other factors to achieve the best performance and economic benefits.

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