Specific Process Knowledge/Lithography/UVLithography: Difference between revisions

* '''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.

** 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|on this page]].

* '''Thickness of resist''': In general, it is recommended to work with an aspect ratio of ~1, i.e. where the width of the pattern is of same size than the thickness of the resist. Furthermore, when you decide for the resist thickness, consider which transfer you need:

** For [[Specific_Process_Knowledge/Lithography/LiftOff|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, investigate the resist etch rate of your process as this might limit the minimum thickness of your resist.

 

* '''Substrate pretreatment''': In many processes it is recommended to [[Specific_Process_Knowledge/Lithography/Pretreatment|pretreat or prime]] your wafer before spin-coating. In some [[Specific_Process_Knowledge/Lithography/Coaters 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 add a pretreatment step prior to spin coating in your process flow.

 

 

* '''Prepare a process flow''' which describes all steps in your UV lithography process. You can find templates [[Specific_Process_Knowledge/Lithography/UVLithography#Resist_Overview|in this table]].