Specific Process Knowledge/Lithography/UVLithography: Difference between revisions
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Before you start your UV processing and request for training on any equipment in UV lithography, go through the following steps: | Before you start your UV processing and request for training on any equipment in UV lithography, go through the following steps: | ||
# '''Resist Type''': Choose the type of resist you wish to use: | |||
** Positive tone resist: Resist exposed to UV light will be dissolved in the developer. The mask is an exact copy of the pattern which is to remain on the wafer. | ** Positive tone resist: Resist exposed to UV light will be dissolved in the developer. The mask is an exact copy of the pattern which is to remain on the wafer. | ||
** Negative tone resist: Resist exposed to UV light will become polymerized and difficult to dissolve. The mask is an inverse copy of the pattern which is to remain on the wafer. | ** Negative tone resist: Resist exposed to UV light will become polymerized and difficult to dissolve. The mask is an inverse copy of the pattern which is to remain on the wafer. | ||
A list of UV lithography resist types available at DTU Danchip can be found [[Specific_Process_Knowledge/Lithography/UVLithography#Resist_Overview|here]]. | A list of UV lithography resist types available at DTU Danchip can be found [[Specific_Process_Knowledge/Lithography/UVLithography#Resist_Overview|here]]. | ||
# '''Thickness of resist''': In general, it is recommended to work with an aspect ratio of ~1, i.e. where the widths of the pattern is in the same order of magnitude than the thickness of the resist. Furthermore, when you decide for the resist thickness, consider which transfer you need: | |||
** For lift-off processes, we recommend resist thicknnesses ~5 times larger than the thickness of the metal to be lifted. | ** For lift-off processes, we recommend resist thicknnesses ~5 times larger than the thickness of the metal to be lifted. | ||
** For dry or wet etch processes, investiagte the etch rates in resist as this might limit the minimum thickness of your resist. | ** For dry or wet etch processes, investiagte the etch rates in resist as this might limit the minimum thickness of your resist. | ||
# '''Mask''': Design and order a photomask for your UV process. A detailed instruction on how to design and order a photomask can be found [[Specific_Process_Knowledge/Lithography/Pattern_Design_and_Mask_Fabrication#Mask_Fabrication|here]]. | |||
# '''Substrate pretreatment''': In many processes it is recommended to pretreat your wafer before spin-coating. In some spin-coaters, these pretreatment processes are included in the spin coating of resist. If you use either the '''RCD8, SSE or a manual spin coater''', you should book equipment for pretreatment prior to spin coating. | |||
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