Protective coating for micro electronic components

How can you specifically protect electronic components in medical implants or devices? How can their lifespan be extended? Dr. Andreas Hogg of Coat-X looks into these issues and has developed an innovative coating that can be used in a myriad of ways. At COMPAMED 2022 he will present the process in the COMPAMED Suppliers Forum.

Dr. Hogg, at the COMPAMED Suppliers Forum by Device Med you will give a presentation titled "Ultra-tight packaging technology for wearable or implantable electronic components and PCBAs". Can you give us a sneak peek and brief insight into this exciting topic?

Andreas Hogg: I would love to. As you may know, the electronics in medical devices such as pacemakers must be encapsulated to prevent any disruptions caused by liquids. To protect the electrical components from the environment, they are often encapsulated using a titanium or steel casing. However, ensuring hermetic sealing in this setting is very expensive and presents certain issues. Chips and sensors for medical devices are also becoming smaller and smaller, while the packaging for these electronics remains large and restricts further miniaturization. You have an empty space that is unusable. Yet with nearly all implants, a smaller size is better for the patient. This prompted our development and idea of ​​developing a coating that is thinner than a single strand of human hair and can be applied on electronic components to fully seal them. This provides device protection for up to ten years! We developed a special coating process that enables us to coat any three-dimensional component in a vacuum chamber. To do this, we introduce special gases that deposit the coating around the component. This gas has one big advantage: The gas molecules are tiny and volatile like air. That means the tiny gas molecules can penetrate even the smallest of cracks and gaps and make their way under an electronic component, for example. This is a completely three-dimensional coating technology. The deposited layer is as thin as food wrap and measures in the range of a few micrometers. We achieved high liquid impermeability by incorporating ultra-thin glass barrier layers in the plastic. Their thickness is in the range of several 100 nanometers, and they are made of glass. We can separate this glass in the gas phase. That means we use this composite material for implants with high-density requirements: First, we separate the parylene polymer base material, then comes a glass layer, followed by plastic and so on. The more often we repeat this process and the more glass barrier layers we incorporate, the denser the coating becomes and the longer the implant lasts inside the body.

Does this mean you can vary the coating thickness and density depending on the component?

Hogg: Yes, we can vary the coating according to requirements. We have already tested the process on neural implants. We encapsulated implants with our coating, placed them in a physiological solution and heated them to 80 degrees Celsius. This enabled us to simulate an implant lifespan of around 14 years at a body temperature of 37 degrees Celsius. That means, this particular implant would work inside the human body for up to 14 years.

We also coated microvalves that are implanted in the eye to control intraocular pressure. They contain a neodymium iron boron magnet (also known as NdFeB magnet) that is very prone to corrosion, which is why it needs a special protective layer that facilitates hermetic sealing.

Wearables are another interesting application for us. The electronic components in wearables are especially prone to corrosion due to sweat or water. Our innovative encapsulation technology extends their lifespan significantly.

Does this mean your process isn’t just used in medical technology, but is also suitable for other types of products?

Hogg: Yes, it is applicable in many different areas of electronics.