Molded Interconnect Devices (MID) enable the production of miniaturized medical devices which deliver higher functionality while offering lower costs. HARTING is one of most experienced and competent providers of precision 3D-MID components. This technology enables our customers to advance the miniaturization of their components and systems.

Cost cutting pressure in the health care sector is generating a rising demand for devices and equipment that permit remote and decentralized patient diagnostics. Mobile medical devices for blood sugar measuring, blood pressure monitoring, and oxygen measuring can be equipped with communication features which provide physicians and health care personnel with a continuous flow of information. In addition, compact hand-held devices contribute to improving diagnostic routines for general practitioners. Improving patients’ quality of life is a priority of the development engineers in the health care market.

Miniaturization Technologies
There are many miniaturization technologies currently available. They include integrated circuits (IC), sensor chips, data recording SOCs (Systems on a Chip), and microcontrollers. But it is only with the advent of new production techniques, such as the injection molding of circuit carriers (MID – Molded Interconnect Devices) that enable the miniaturization of the devices and the implementation of new functionality into the devices.

MID’s are injection molded plastic parts with integrated electrical circuits. These circuits can be arranged on the 3D surface as required by the design engineer. The 3D-MID production processes enable the integration of IC chips and small flat components (SMDs) onto the injection molded housings. Moreover, this method allows the creation of gaps and recesses, channels and apertures for sensors, contact elements, and other devices. This provides developers with improved flexibility in designing specific components, while realizing cost-efficient production processes at the same time.

Advantages of 3D Component Manufacturing
MID technology allows the production of integrated components with very compact size, and can be developed to precise dimensions. In addition, the latest thermoplastic materials can be utilized and are capable of withstanding thermal stress. Moreover, construction modifications are easy to implement by way of laser direct structuring. HARTING Mitronics utilizes two 3D-MID production techniques:

  • Two-Step Injection Molding (2K) – This involves the use of two plastic materials, low tooling costs and flexibility for design and construction of the MID. The assembly of IC chips and SMDs is usually performed by a soldering of which one can be metalized in order to create the circuit paths, while the second material remains passive. In most instances the minimum widths and gaps between the circuit paths are around 400 µm. The two-step (2K) technique enables the production of large unit volumes at low costs.
  • Laser Direct Structuring (LDS) – The LDS technique utilizes a laser beam which activates the metal additives of a special polymer, which subsequently enables the plating of the circuit paths. This technique creates circuit paths and gaps of 150 µm. This LDS technique is characterized by low tooling costs and flexibility for design and construction of the MID.

3D-MID components are manufactured in a series of stages that add both circuitry and components to a molded plastic substrate that can be shaped to the device designer’s requirements.

The assembly of IC chips and SMDs is usually performed by a soldering technique. Flip-chip assembly as well as the use of a conductive adhesive are also options. Wire bonding permits the placement of the components in a multitude of arrays. Flip-chip methods are used to achieve extremely compact component sizes. In the case of SMDs the assembly and/or the connection between the electrical contact surfaces and the housing is done by electro conductive adhesive, reflow soldering, or vapor phase solder techniques.

The mounting of a completed 3D-MID component can be achieved by one of the techniques described above. 3D-MID components can be added to PCBs just like any other SMD part, allowing for improved manufacturing flexibility and cost savings.