Template-based 3D microfabrication technology that adds functionality to plastic micro-AM parts

There is no doubt that the market for MEMS devices is growing rapidly, due to the many advantages that these devices offer, such as their small size, low power consumption, and high reliability. One of the main reasons for the growth of the MEMS market is the increasing demand for miniaturisation. As electronic devices continue to shrink in size, MEMS devices are becoming more and more attractive due to their small dimensions, and with the ongoing trend towards wearable electronics, there is a growing need for even smaller and more versatile MEMS devices.

Andreas Frölich, CEO at Horizon, says: “MEMS devices are also benefiting from the increasing demands for reliability and safety in electronic systems. With the ever-growing range of applications that MEMS are considered for, there is also a growing need for components that can withstand harsh environments or extreme conditions, fit a small form factor and operate reliably. MEMS devices need housings for a variety of reasons, and these housing are an essential part of the system since they constitute the interface of the actual MEMS to the rest of the device and the rest of the world.”

One one hand, housing protects delicate MEMS devices from physical damage, and also helps to keep dust and other contaminants away from the device, which could otherwise interfere with its operation. 

On the other hand, the housing has to admit all things the MEMS needs to fulfil its function. At a minimum this is electrical power, but additionally light, radio signals or media that the MEMS device might be supposed to measure. The housing also provides a way to attach the device in a defined way to a larger system, such as a printed circuit board or a chip, and in some cases the housing may also need to dissipate heat generated by the device, or to provide electromagnetic shielding to protect the device from interference. 

Horizon has identified that the use of AM to develop MEMS housings creates a number of opportunities for manufacturers. For example, AM offers a high degree of freedom in terms of design, which allows for the creation of complex shapes that would be difficult to produce using traditional machining methods. In addition, micro-AM can be used to create features with precision on the micrometre scale, which is important for MEMS and optics applications.

Horizon offers an in-house post-build coating technology that augments the opportunities afforded through the use of micro-AM-produced MEMS packaging by adding functionality, specifically conductivity and environmental resistance. To introduce conductivity, once the part is produced on a polymer-AM platform, it is either wholly or selectively coated with a conductive layer. Horizon can even coat difficult areas homogeneously such as long narrow channel and undercuts. In addition, microfabricated 3D templates can also be coated with metal oxides to make parts compatible with aggressive chemical environments and in some cases can notably increase the resistance to high temperatures and mechanical stresses.

Frölich continues: “While additive manufacturing is not typically considered a mass-production technology, the reduction in the size of electronics and optics — and the accompanying shrinkage of packaging — has made micro-AM a viable production alternative for MEMS housings for small to medium batch sizes. In addition to the precision offered by micro-AM, and the ability to build geometrically complex housings, an intelligent use of our post-processes can increase the functionality of the packaging, for example by reducing stray light in the infrared, having integrated electrical conductors, or making an off-the-shelf MEMS system usable in a harsh environment by adapting the right packaging.”