Interconnection MID in pole position


Three-dimensional moulded interconnect devices are a welcome addition to conventional printed circuit boards and are particularly well suited to Industry 4.0


applications. The example of a smoke detector illustrates how design and functional integration are simplified with this technology.


W


hether rigid or flexible, printed circuit boards are a virtually indispensable part of electronic


devices as interconnect devices. Plastic moulded interconnect devices (MIDs) offer many advantages with regard to connection technology, including the combination of electrical and mechanical functions in a single component. This makes it possible to use the housing and other moulded inner structures as an interconnect device, sometimes eliminating the need for a PCB.


Three-dimensional functional integration


The MID is a multifunctional component with sensors arranged and aligned with a high precision combined with an RFID antenna for sending and receiving signals. This concentration of functions on a single carrier material enables development engineers to create three-dimensional microelectromechanical systems (MEMS). MIDs are ideally suited for this purpose, particularly when manufacturing large and very large volumes.


MID technology in detail Three-dimensional MIDs are manufactured using the LDS (laser direct structuring) method: the shape of the interconnect device desired by the customer is created in a single-component injection moulding process, which offers virtually unlimited freedom for three-dimensional design.


Smoke detector concept based on 3D MID. The battery holder is integrated directly in the moulded part While conventional printed circuit


boards use FR4 fiberglass fabric or similar base material, moulded interconnect devices are built from thermoplastics. The thermoplastic base material is first compounded with a (nonconductive) laser- activated metal-organic additive. The LDS laser beam structures the


circuit pattern onto the device by cleaving the metal-organic additives while roughening and ablating the plastic precisely where the beam strikes the surface. Copper seeds split out from the additive, attracting free copper in the subsequent metallisation step. In the following electroless metallisation


process within a copper bath the copper seeds created in the lasering step now attract solid copper out of solution. After copper plating, electroless nickel and immersion gold (ENIG) layers may be added to the copper layer. When an MID is not soldered or bonded, nickel alone over copper is sufficient. ENIG metallisation ensures good surface properties for designs where SMT soldering or Wire-Bonded component placement is desired.


Potential of the technology In modern connection technology, engineers use flex or rigid-flex printed circuit boards or wires if an electrical connection is to be established between several printed circuit boards in various positions and alignments. Here the core benefits of the MIDs allows a reduced number of parts, resulting in process,


material, and logistics savings while at the same time raising quality with the reduction of assembly steps and expenses. MID technology holds enormous potential for functionally oriented product development with optimised manufacturing processes. Flexible printed circuit boards are often a suitable solution for bypassing physical distances at changing angles but for the precise positioning and fixing of sensors such as Hall-effect sensors or LED lighting on Flex, this incurs extra costs. The MID component enables possibilities in the microscale and is unbeatable here, with the precise positioning of components and defined angles in arrangements being easy to realise. To achieve a fully realised MID product, antennas or shields can be attached to the carrier and connected to the circuit. Circuit density has been achieved in large series production with an 80 m circuit trace / 80 m space and contributes to greater opportunity for miniaturisation.


Example: smoke detectors Today's smoke detectors are ideally suited for upgrading to MID technology. The carrier material for smoke detectors today is made up of plastic components and provides a moulded part to which the components may be fixed.


Plastic substrate with integrated circuit paths: wires and connecting plugs no longer required


Three-dimensional moulded interconnect devices www.cieonline.co.uk


MID technology enables significant simplification of the design and the functional integration associated with the smoke detector. The battery holder is integrated directly in the MID part, thus forming all the metal contacts. The two connecting cables and the elaborate soldering process for bonding are now redundant. Standard SMDs can be soldered directly to the plastic, thereby saving costs while also allowing placement to be performed using pick-and-place machines, reducing personnel expenses for the assembly process to a minimum. The number of components is also reduced to a minimum – the printed circuit board is


no longer required and circuit paths inscribed directly on the plastic replace the wires, which means that connecting plugs are also not needed. Moreover, it is easy to integrate antennas in order to network the smoke detectors. By adapting the laser programming, any antenna structure can be applied directly to the same carrier material. Last but not least, because the MID technology eliminates the need for mechanical switches, it is simple to metallise a capacitive surface and use it as a capacitive switch.


Proven in industry Three-dimensional MID technology has long been tried and tested in industry. It was first employed for the challenges of spatial antenna construction, as well as for expanding frequency ranges, integration densities and available installation spaces for high-frequency applications. Moulded interconnect devices are suitable for 3D antennas in frequency ranges exceeding 6 GHz, reliable for Bluetooth, LTE or Wi-Fi applications. Antennas manufactured using this procedure can be found in billions of smartphones, tablets and other portable devices.


Millions of mobile payment terminals also contain MID solutions. All known areas of industry in which currents flow or shielding is necessary harbour countless possible applications for moulded interconnect devices. Furthermore, the mechatronic advantages of the technology enable holders to be designed for energy sources such as button batteries, making the interconnect device an elegant solution.


www.multipledim.com


Components in Electronics


June 2017 17


Page 1  |  Page 2  |  Page 3  |  Page 4  |  Page 5  |  Page 6  |  Page 7  |  Page 8  |  Page 9  |  Page 10  |  Page 11  |  Page 12  |  Page 13  |  Page 14  |  Page 15  |  Page 16  |  Page 17  |  Page 18  |  Page 19  |  Page 20  |  Page 21  |  Page 22  |  Page 23  |  Page 24  |  Page 25  |  Page 26  |  Page 27  |  Page 28  |  Page 29  |  Page 30  |  Page 31  |  Page 32  |  Page 33  |  Page 34  |  Page 35  |  Page 36  |  Page 37  |  Page 38  |  Page 39  |  Page 40  |  Page 41  |  Page 42  |  Page 43  |  Page 44  |  Page 45  |  Page 46  |  Page 47  |  Page 48  |  Page 49  |  Page 50  |  Page 51  |  Page 52