Permanent Epoxy Photoresist for Dielectrics in Organic TFT Back-Planes

Organic field-effect transistor (OFET) is a transistor that uses an organic semiconductor in its channel. These devices are being developed with low-cost, low temperature and large-area electronics in mind. Organic electronics can also be manufactured on polymeric substrates such as PET or PEN. This allows for large-scale roll-to-roll manufacture that could be used to produce large area, low-cost active matrix TFT’s for display applications.

Both top and bottom-gate configurations can use organic polymers such as SU-8 for the interlayer dielectric separating the active TFT from the pixel electrode.

SU-8: Benefits/Attributes

  • Highly crosslinked system with high structural strength
  • Highly transparent in the visible range
  • Options for low temperature bakes
  • Photo imageable
  • Fast photospeeds for high volume manufacture
  • Low dielectric constants with high breakdown voltages

SU-8 2000 Material Properties

Dielectric Constant
3.0 @ 1kHz to 10kHz, 4.1 @ 1GHz
Volume Resistance
2.8×1016 Ω/cm
Surface Resistance
Breakdown Voltage
112 V/μm
Dissipation Factor
0.015 @ 1GHz