Molded Interconnect Device
Encyclopedia
A Molded Interconnect Device is an injection molded
thermoplastic
part with integrated electronic circuit
traces. The use of high temperature thermoplastics and their structured metallization opens a new dimension of circuit carrier design to the electronics industry
.. This technology combines plastic substrate
/housing with circuitry into a single part through selective metallization.
Laser Direct Structuring (LDS)
The LDS process uses a thermoplastic material, doped with a metal-plastic additive activated by means of laser. The basic component is single-component injection molded, with practically no restrictions in terms of 3D design freedom. A laser then writes the course of the later circuit trace on the plastic. Where the laser beam hits the plastic the metall additive forms a micro-rough track. The metal particles of this track form the nuclei for the subsequent metallization. In an electroless copper bath the conductor path layers arise precisely on these tracks. Successively layers of copper, nickel and gold finish can be raised in this way.
The LDS process is characterized by
The LDS process is patented by LPKF Laser & Electronics AG
Two Shot Molding
Two shot molding is an injection molding process using two different resins and only one of the two resins is platable. Typically the platable substrate is ABS and the non-platable substrate is polycarbonate
. In a two shot component, these are then submitted to an electroless plating process where the butadiene is used to chemically roughen the surface and allow adhesion of a copper primary layer. The plating chemistry can be controlled to prevent the roughening of the polycarbonate portions of the component. While not commonly found out side of cellphone antenna production, this technology is public and widely available.
Injection molding
Injection molding is a manufacturing process for producing parts from both thermoplastic and thermosetting plastic materials. Material is fed into a heated barrel, mixed, and forced into a mold cavity where it cools and hardens to the configuration of the cavity...
thermoplastic
Thermoplastic
Thermoplastic, also known as a thermosoftening plastic, is a polymer that turns to a liquid when heated and freezes to a very glassy state when cooled sufficiently...
part with integrated electronic circuit
Electronic circuit
An electronic circuit is composed of individual electronic components, such as resistors, transistors, capacitors, inductors and diodes, connected by conductive wires or traces through which electric current can flow...
traces. The use of high temperature thermoplastics and their structured metallization opens a new dimension of circuit carrier design to the electronics industry
Electronics
Electronics is the branch of science, engineering and technology that deals with electrical circuits involving active electrical components such as vacuum tubes, transistors, diodes and integrated circuits, and associated passive interconnection technologies...
.. This technology combines plastic substrate
Substrate
Substrate may mean:*Substrate , Natural stone, masonry surface, ceramic and porcelain tiles*Substrate , the material used in the bottom of an aquarium*Substrate , the material used in the bottom of a vivarium or terrarium...
/housing with circuitry into a single part through selective metallization.
Applications
Key markets for the MID technology are consumer electronic, telecommunication, automotive and medical. A very common application for MIDs are integrated antennas in cellphones and other mobile devices including laptops and netbooks.Manufacturing methods
Molded Interconnect Devices are typically manufactured in these technologies:Laser Direct Structuring (LDS)
The LDS process uses a thermoplastic material, doped with a metal-plastic additive activated by means of laser. The basic component is single-component injection molded, with practically no restrictions in terms of 3D design freedom. A laser then writes the course of the later circuit trace on the plastic. Where the laser beam hits the plastic the metall additive forms a micro-rough track. The metal particles of this track form the nuclei for the subsequent metallization. In an electroless copper bath the conductor path layers arise precisely on these tracks. Successively layers of copper, nickel and gold finish can be raised in this way.
The LDS process is characterized by
- single-component injection molding
- a wide range of materials is available
- full three-dimensionality in a sphere
- flexibility: for a changed routing of traces, only new control data have to be transmitted to the laser unit. Thus different functional components can be produced from one basic unit
- precision: finest conductor pathes with a diameter of < 80 micrometres are possible
The LDS process is patented by LPKF Laser & Electronics AG
Two Shot Molding
Two shot molding is an injection molding process using two different resins and only one of the two resins is platable. Typically the platable substrate is ABS and the non-platable substrate is polycarbonate
Polycarbonate
PolycarbonatePhysical PropertiesDensity 1.20–1.22 g/cm3Abbe number 34.0Refractive index 1.584–1.586FlammabilityV0-V2Limiting oxygen index25–27%Water absorption – Equilibrium0.16–0.35%Water absorption – over 24 hours0.1%...
. In a two shot component, these are then submitted to an electroless plating process where the butadiene is used to chemically roughen the surface and allow adhesion of a copper primary layer. The plating chemistry can be controlled to prevent the roughening of the polycarbonate portions of the component. While not commonly found out side of cellphone antenna production, this technology is public and widely available.
External links
- TNO.nl/mid Independent research organisation which supports and develops MID production processes for external parties.
- LPKFUSA.com/MID Further information about the LDS process
- 3D-MID.de
- TycoElectronics.com/MID
- ArlingtonPlating.com
- devicelink.com/mpmn/archive/10/04/014.html
- phillipsplastics.com/case_studies/case-studies/multi-shot-holds-it-all-together