MD&M West Trade show Feb. 7-9, 2023

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Engineered Plating for Semiconductors

Engineered plating for Semiconductors is a plating solution to improve conductivity and wear resistance. The primary use of a semiconductor is for electronic applications. Most electronics contain one form of semiconductor; capacitors, diodes, resistors, and transistors are all forms of Semiconductors. These Semiconductors have many components, including lead connections, lead wires, body, and chips.

A semiconductor is usually made of multiple materials. By and large, most are made of silicon. Other rare materials used in semiconductors are Germanium and Gallium Arsenide. The lead wires and body are often made of a common metal like Copper or steel. If the semiconductor leads and body were entirely composed of Gold or Silver, plating would not be needed. Generally, making the part entirely of precious metal is not cost-effective. For this reason, engineered plating for semiconductors with precious metal is a great option that offers equal benefits in maximizing the conductor’s effectiveness.

Engineered plating image for semiconductors on a flat surface

Conductivity and Specifications of Plated Finishes

Plating finishElectric conductivity (10.E6 Siemens/m)Electric resistivity (10.E-8 Ohms.m)Specifications
Silver 62,11,6MIL-QQ-S-365
Copper 58,71,7MIL-C14550
Gold44,22,3MIL-G-45204
Palladium9,510,5MIL-P-45209B
Rhodium21,14,6MIL-R-46085
Platinum9,410,5GE-F70J-WB2

Precious Metal Plating for Semiconductors

The choice for precious metal plating on a semiconductor depends on the highest conductivity and if there is a need for corrosion resistance. Silver has a very high conductivity but does not offer the highest corrosion resistance. At ProPlate®, we use Silver as a final finish for many semiconductors, specifically for conductivity. Gold is an excellent choice for conductivity as well as corrosion resistance. Unlike Silver and Copper, Gold does not react with oxygen, so it is virtually immune to rust and corrosion.

The thickness of the Gold, as well as the substrate it is plated on, all play factors in the duration of the corrosion resistance as well as the conductivity of the part. Rust is a major concern if the part is a low-quality steel substrate. The thickness of the Gold final layer should be higher so the rust cannot bleed through. Copper is also a common base material used on semiconductors’ leads, heads, and circuit boards.

The copper base material provides a very high conductivity and does not rust. However, copper is known to corrode or form a patina that can be detrimental to the conductor. This is when a precious metal finish will not only highly improve and sustain conductivity but also increase the part’s longevity. The engineer might also suggest a nickel underplate to create a diffusion barrier between the steel and gold layer. This helps prevent corrosion and helps prevent rust or copper that might bleed into the final gold finish. Precious metal is always the best choice for a final layer on the semiconductor’s most critical components.

Plating Techniques for Semiconductors and Circuit Boards

The plating techniques used for semiconductors can range from industry-standard processes like barrel or rack plating to more complex methods like selective plating. The techniques used vary and are dependent on many factors. Some of these factors may include the size of the part, the shape of the part, and the areas of the part the customer wants plated.

ProPlate® has perfected the process of plating parts, specifically with long leads used in military applications. We have a team of engineers and a lot of experience plating on semiconductors. The processes we have developed are now standard and repeatable with complete success. In more complex semiconductors with intricate circuit boards, we are able to work with new part process development engineers to develop an engineered plating rack specifically for our customer’s requests. Particularly, some of these techniques might include attaching specific leads to the points desired to be plated. This technique is called selective plating. With this in mind, ProPlate’s experience with complex plating projects helps us work with the customers to take on the most challenging jobs and have repeated success.

Close up image of engineered plating for semiconductors

Rhodium Plating on Semiconductors

Rhodium plating is well suited for such applications as semiconductors that require protection from the environment it is placed in.  Also, because of its’ high-temperature tolerance to oxidation, Rhodium is an excellent choice for high voltage/high amperage electrical contacts where contact arcing would otherwise cause the formation of highly electrically resistive oxide formations on the contact surface. As has been noted, Rhodium is excellent in very high-temperature applications. Rhodium will provide a longer life cycle than, for example, Gold. The Rhodium plating also has a high melting point. Furthermore, Rhodium will reliably operate beyond 1000F.

Final Quality Testing

In conclusion, the final inspection of the semiconductors is very thorough. Specifically, they go through a rigorous adhesion, visual, and thickness inspection to ensure a quality product that meets all the industry requirements. A final steam-age test is often used on our plated semiconductors. This test aligns with military specification MIL-STD-202. The test is to ensure the part’s longevity and that it has a sufficient amount of plating and coverage. This test also places the part in a corrosive environment to determine the final plated conductor’s longevity. To sum up, ProPlate® uses MIL-STD-202 to comply with specific electronic industry standards for electroplated parts.

To discuss more plating options, please call our team at 763-427-0112.

To request a quote, please visit us at https://proplate.com/request-a-quote/.

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