Microscopic four-point probe (u4PP) based on SU-8 cantilevers

Four-point probes (4PPs) are used for the resistivity measurement of thin metal or semiconductor films. There is an interest in miniaturization of 4PPs to obtain higher surface sensitivity, increased spatial resolution and less damage to the sample. Several attempts have been made to reduce the probe spacing, e.g. a four-tip scanning tunneling microscope (STM) was reported and a 4PP based on silicon cantilevers was designed. This paper shows design, fabrication and characterisation of a micrometer scale 4PP (micro4PP) device based on SU-8-cantilevers. The photoresist SU-8 has appropriate mechanical properties that make it an excellent candidate material for active parts in selecterd micro-mechanical applications such as cantilevers for scanning probe methods.