For special applications in which metal layers with a thickness of a few hundred nanometres are to be generated by lift-off techniques, accordingly higher layers are needed. With AR-P 6200.13, 800 nm thick layers are obtained at a spin speed of 1000 rpm, and with AR-P 6200.18 even 1.5 µm thick films are realised.
The degree of the generated undercut could be specifically adjusted by increasing the exposure dose (F Fig. 1-3). With this system, each user is able to choose the most favourable profile for the desired lift-off process. For the manufacture of nano-conducting paths with a metal height of a few 10 nm, still thin 100-200 nm resist layers should be used. In contrast allow „thick“ lift-off structures even the manufacture of columns with a height of a few 100 nm and an Ø <100 nm (e.g. nanowires).
Fig. 1 AR-P 6200.13, 823 nm film, dose: 1200 pC/cm
Fig. 2 AR-P 6200.13, 823 nm film, dose: 1440 pC/cm
Fig. 3 AR-P 6200.13, 823 nm film, dose: 1728 pC/cm
Since generally a considerable amount of polymer is dissolved in the developer during the development of thick layers, a brief rinsing with fresh developer and / or MIBK is highly recommended. The deposition of polymer residues or particles from the developer solution on the substrate can thus be effectively avoided. The subsequent stopping is carried out in AR 600-60.