Three-dimensional molded interconnect devices (MIDs) are regarded as an intelligent alternative to conventional circuit boards whenever the latter reach their limitations because of their two-dimensional structure. The advantage of these three-dimensional layouts is that they can be miniaturized with their complex electrical and electronics assemblies and can be made more compact through the integration of various functions. Conductive tracks and electronic components can be applied directly, making the use of conductive cables and pc boards unnecessary. Mechatronic systems can also be integrated.

MID technology – excellent future prospects

For the production of three-dimensional molded interconnect devices (MIDs), the innovative process of laser direct structuring (LDS) is used. It was developed by LPKF Laser & Electronics AG in Garbsen, Germany. Existing series applications as well as many ongoing development projects indicate that the market for LDS components will grow strongly in the coming years.

Laser direct structuring – environmentally friendly, flexible, maximum design freedom

The process is based on thermoplastics doped with a catalyst containing metal oxide. First of all, the three-dimensional MID is produced by injection molding. After that, a laser burns a high-resolution wiring diagram onto the surface of the molded part. The uppermost polymer layer is stripped off, exposing and activating the metallizing nuclei of the additive. The activated areas are then provided with copper, nickel and/or gold conductive tracks in metalizing baths without using a current.

Tailor-made polyester with a wide processing window

LANXESS has a number of tailor-made types of Pocan® in its portfolio for the laser direct structuring process, all of which fulfill the respective requirements. The materials open up a wide processing window for the manufacturer in all stages of the LDS process – from material preparation and injection molding to metallization and, where necessary, subsequent soldering.

Pocan® DP T 7140 LDS, which is used, for example, for RFID transponders, is especially suitable for components subjected to high thermal stresses because of its high heat distortion temperature of 250 °C. Practical trials have confirmed that the material can also withstand the temperatures prevailing in reflow soldering processes (convection soldering, vapor phase soldering). Here, furnace temperatures can reach up to 280 °C for short periods. Lead-free soldering processes of this kind are needed in many applications for manufacturing MIDs.

A variety of Pocan® grades suitable for LDS basically have good prospects of success in areas in which pc boards are used. In the automotive industry, for instance, items such as rotary transducers, sensor housings, actuators and electrical components of locking systems are manufactured from these plastics using MID technology. Potential applications in the E&E industry include connectors and connector boards, ISDN connector bases, sensors and cell phone antennas. Other promising applications can be found in the IT and household appliance industries, medical technology, mechanical engineering and consumer electronics.