University: Heriot Watt University
Sector(s): Electronics, Sensors & Photonics, Electronics, Sensors & Photonics, Engineering & Manufacturing, Information & Communications Technologies, Materials, Other
Problem this technology solves:
Provides an alternative to subtractive de-metallisation processes (e.g. etching/stripping) using an additive process support by a novel bio-degradable photo-initiator package.
Flexible circuits comprising plastics or polymers are increasingly common within mobile phones, laptops and PDA’s due to their flexibility, durability, chemical resistance and light weight. Many flex circuits are based on polyester, Liquid Crystalline Polymers (LCP) or more commonly, Polyimide. A key challenge in making such circuits is the metallisation step where a metal film such as copper is laminated to the polymer using adhesive or deposited under vacuum or another chemical process. The circuit is then developed using a suitable chemical etching process creating large volumes of waste solution for disposal.
Polyimide offers a balance of properties suitable for flex circuits; Polyimide polymers contain an imide ring that when treated with a caustic solution (e.g. Potassium Hydroxide, KOH) can be opened and then “ion-exchanged” with a suitable reagent (e.g Silver Nitrate, AgNO3) to form a metal ion containing active site suitable for further chemical or Photo-deposition reactions to form conductive tracks.
Building on previous work by Hoyd-Gigg Ng et al. [1,2], Heriot-Watt has developed an additive film metallisation process using a novel light activated photo-catalysis process to directly create conductive metal tracks on polymer films. Using short wave UV or visible light to initiate a reaction, the tracks show high adhesion to Polyimide and are suitable for electro/ electroless plating using existing bath technologies (Gold/ Copper/ Silver etc.).
- Direct writing of metallic tracks on films
- Additive metallisation process – reduces waste/ reagent disposal costs
- Reel to Reel processing possible using suitable line
- Compatible with existing electroless/ electroplating bath solutions
- Flex & Flex-Rigid PCB’s / Micro-electronics circuits on Polyimide film
- RF Shielding, Antenna & PCB prototyping
- Applicable to planar surfaces – films, boards etc…
Technology and “Proof of Concept” has been demonstrated on a lab bench using PCB grade Polyimide film (DuPont), exposure and HWU proprietary catalyst/ coating producing conductive tracks of <10 micron line width.
Technology is available for license in all fields of use on exclusive/ non-exclusive basis. Design, Performance & Experimental Data is available under confidentiality agreement only.
Heriot-Watt now seeks microelectronic system developers and integrators with experience of Flex/ Flex-Rigid PCB manufacture who see utility in the applications of this technology.
Partners should have an interest in either obtaining a licence to develop this technology or to act as industrial sponsors to collaborate and provide financial (or “in-kind”) support for technological developments in specific defined areas.
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