Specific Process Knowledge/Lithography/SU-8: Difference between revisions
No edit summary |
|||
| Line 55: | Line 55: | ||
==Exposure== | ==Exposure== | ||
The exposure step is usually done in near UV-radiation at aligners system which blocks the wavelengths below the i-line (365nm wavelength). [[Specific Process Knowledge/Lithography/UVExposure#KS Aligner|KS Aligner]] and [[Specific_Process_Knowledge/Lithography/UVExposure#Aligner:_MA6_-_2|Aligner: MA6-2]] both have i-line filters. | The exposure step is usually done in near UV-radiation at aligners system which blocks the wavelengths below the i-line (365nm wavelength). [[Specific Process Knowledge/Lithography/UVExposure#KS Aligner|KS Aligner]] and [[Specific_Process_Knowledge/Lithography/UVExposure#Aligner:_MA6_-_2|Aligner: MA6-2]] both have i-line filters. [[Specific_Process_Knowledge/Lithography/UVExposure#Aligner:_Maskless_01|Aligner: Maskless 01 (MLA1)]] has a 365nm source. Exposure on [[Specific_Process_Knowledge/Lithography/UVExposure#Aligner:_Maskless_02|Aligner: Maskless 02 (MLA2)]] using the 375nm source works, but needs a higher dose, and the resist thickness is limited on this tool. | ||
Duration of the UV-exposure depends of resist thickness, but notice that if the UV exposure becomes long then the heating at the interface with the mask can cause formation of hard skin at the surface of SU-8 so called T-topping phenomena. The the main rule is if the dose of the exposure exceeds 250-300 mJ/cm2 it is recommended to do a multiple exposure instead and have a waiting time between the steps to allow the resist cool down. | Duration of the UV-exposure depends of resist thickness, but notice that if the UV exposure becomes long then the heating at the interface with the mask can cause formation of hard skin at the surface of SU-8 so called T-topping phenomena. The the main rule is if the dose of the exposure exceeds 250-300 mJ/cm2 it is recommended to do a multiple exposure instead and have a waiting time between the steps to allow the resist cool down. | ||