Conductive polymers like polyaniline and polythiophene are in high demand for use in optoelectronics and organic electronics. For example, these materials are used to make organic thin-film transistors or light-emitting devices.
There is a new application of conductive thin films made from conductive polymer thin film as charge dissipation layer for state of the art patterning methods such as Electron beam lithography charge dissipation (EBL) focused-ion beam (FIB) etching on challenging substrates.
Thin layers of polythiophene can dissipate accumulated charges in electron-beam photography of wide bandgap semiconductors (e.g., gallium nitride and zinc oxide, as well as focused ion beam patterning glass.
EBL is a technique that creates dense periodic nanopatterns of hydrogen silsesquioxane negative-type e beam resist. This allows passive photonic devices to be made in semiconductors by a dry etch process. The electron beam lithography charge dissipation process is a type of X-Ray imaging that uses beams to transfer patterns into materials. It has been around since the late 1970s. Still, it only became popular for manufacturing purposes about 20 years ago because improvements in charge dissipation were needed before this technique could become widespread across all industries.
H-SiOx (HSQ), a silsesquioxane-based semiconductor grade polymer, is a high-purity semiconductor grade material that can be used as a negative tone resist in electron beam patterns, EUV, and Nano imprint lithography, and Step and Flash Item Lithography (SFIL). It can be easily dissolved in non-polar organic solvents such as methyl isobutylketone, methyl siloxane, and toluene.
A dense pattern can be made with a sub-10 nm half-pitch depending on the thickness of the film. In addition, HSQ Resist Supplier can be prepared using a percentage by weight of silica resin in semiconductor quality MIBK at concentrations ranging between 1 – 20 % / wt. Therefore, you can purchase prepared solutions in volumes of 20 to 100 ml.
- H-SiQ can be applied using spin coating at 1000-6000 rpm.
- H-SiQ comes prefiltered to 0.22 um for 10% and 0.45 um for 10%. Additional filtration is not usually required. Additional filtration may be required, but it is best to filter the HSiQ when an application with PTFE or nylon filters media. Filtering with a syringe using a Luer lock filter disc is not recommended. Use only HDPE and PP nonpyrogenic materials with the PTFE filter media. Avoid using syringes and filters that contain silicon, silicon oils or rubber, or glass prefilters.
- For high contrast and sensitivity, bake after coating at 120°C for 2 minutes.
- H-SiQ can be developed using your favorite HSQ developer (TMAH, NaOH/NaCl) after EBL.
- The H-SiQ film cures with etching resistance comparable to traditional HHSQ: 30 SCCM CF4 30 MTOR 100 W 33 nm/min.
The use of conductive polymers for electron beam lithography charge dissipation is an emerging subject that will see more research in the future. Conducting polymers are already being used for other purposes, so it’s not a stretch to imagine them being adapted for this purpose as well.