National Physical Laboratory

Printed Electronics

Printed electronics

The Electronics Interconnection Group of the National Physical Laboratory (NPL) has been involved with characterising printed electronics systems for more than a decade. The Group is developing a suite of metrology methods to enable improved manufacturability and lifetime prediction of plastic electronics systems. Key process variables in a range of PE systems are being characterised and combinatorial metrology tools for assessing fitness for purpose are being developed. Methods in identifying degradation in material and electrical properties are being developed.

Disassembly of circuit using printed inks and interconnect
Disassembly of circuit using
printed inks and interconnect




Recycling focus

Together with partners GEM and In2Tec, we have developed a highly recyclable printed circuit assembly system (ReUSE) based on printed conductor tracks, dielectrics and conductive component attachment. This structure can easily dissembled at end of life in warm water where the adhesive layer softens allowing easy removal of parts and layers. However, extensive testing has shown that an assembly can withstand a wide range of operating conditions.

This technology is the focus of a current collaborative research programme to develop more complex assembly architectures for a wider range of electronics applications.

Defects in printed electronics
Defects in printed
electronics


Detecting cure and defects in printed inks

Metrology in performance and lifetime testing of carbon, silver and graphene printed inks on flexible substrates such as PET and PEN have been developed. We have been investigating methods for interrogating wet inks to determine their fully cured electrical performance and also looking at printed electronics defect characterisation and detection. Our current projects include characterisation of electrochemical inks and investigating methods of defect detection for high speed printed electronics manufacture.

This work over the last decade has resulted in the Electronics Interconnection Group developing expertise in a suite of measurement techniques for characterising printed electronics systems.

 

 

 

Details of the services available are as follows:

Conductivity test pattern
Conductivity test pattern



Conductivity

  • Four point conductivity measurements in conjunction with thickness measurements to determine normalised W/sq
  • Standard test pattern (NPL TB108)
    • Parallel and perpendicular to print direction
    • Three feature sizes (0.5, 0.75 and 1.0 mm track/gap)
    • 1105 squares for each pattern


Thermal coefficient of resistivity

Thermal coefficient of resistance measurement
Thermal coefficient of resistance
measurement
  • Test fixture designed to operate -40 to +150 ºC


Adhesion

  • Conductive and dielectric ink adhesion testing


Print thickness/definition

  • Contact and non-contact techniques


Surface insulation resistance

Adhesion testing of printed inks
Adhesion testing of printed inks


Ageing and performance degradation of inks and conductive adhesives

  • Thermal
  • Damp heat
  • Thermal cycling (-55 to 150 ºC)
  • Thermal shock testing (-55 to 300 ºC)
  • Combinational testing (thermal cycling and damp heat)
  • Continuous and periodic monitoring
Failure in conductive adhesive interconnect
Failure in conductive adhesive interconnect
Surface insulation resistance testing of printed inks
Surface insulation resistance testing of printed inks
Track profiling for printed electronics
Track profiling for printed electronics


Measuring the Effect of Substrate and Component Finishes on the Reliability of Isotropic Electrically Conductive Adhesive Joints

Last Updated: 14 Sep 2016
Created: 5 Jan 2015

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