Before the coating of the SU-8, you must use the omnicoat, which provide the better adhesion for SU-8.
Hi,
I think following links are useful for you. You can use photo lithography or electron beam lithography.
Article High-resolution pattern generation using the epoxy novolak S...
Hi,
I understand you want to pattern SU-8 which you want to use as mask. Right?
SU-8 is negative photo resist and and can be patterned by using photo-lithography techniques. The type of SU-8 is also important for what you want to do with it later, as mask.
Hi Abhishek,
SU-8 is a thick negative photoresist and as the above cmention can be patterned by ebeam or photolithography. We typically spin coat 100um layers of SU-8 using Su-8 2075 in our laboratory.
Because SU-8 is a negative photoresist, areas on your sample which are exposed to UV ,i.e. those which are clear on your photomask, become crosslinked. The crosslinked polymers then become less soluble in the resist developer (solvent) whilst the regions which were protected by the photomask (the opaque/dark/chrome regions) remain soluble and are removed, leaving behind your pattern. However, the crosslinked polymers will eventually dissolve in the developer resulting poor resolution/definition of your design, i. e. Over developing resulting in undercutting. For this reason well defined development times are a cyticall partof photolithography.
One great aspect of SU-8 to note when developing is that polymers which have not been crosslinked turn a white / milky colour when sprayed with isopropanol. This can give an indication of whether the development time has been sufficient and the development is complete.
Feel free to contact me with any other questions.
Adam
The procedure depends on your application but generally:
Prepare/clean substrate
Spin coat SU8 to desired thickness, you will need to research the spin profiles for your chosen SU8 to see the rpm required for the thickness needed.
Soft bake - @ 90C but time will depend on thickness
Expose substrate to UV with photomask inserted - mj/cm^2 will depend on thickness
Post bake-@ 90c but time will depend on thickness
Develop - SU8 developer/EC solvent - development time will depend on thickness
Optional hard bake/process complete.
In your case, You can use both UV- lithography as well e-beam lithography.
SU-8 is a neagtive tone resist, which is highly dependent on the atmospheric condition during the lithography. So you have to make sure about the complete process during the lithography. You can use SU-8 2025 as well depending upon the thickness you desire.
The complete process,you can also found from the microchem site as attached pdf.
Before the coating of the SU-8, you must use the omnicoat, which provide the better adhesion for SU-8.
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