With respect to the raw material used, e-beam resists fall into four different categories:
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- PMMA- resists (AR-P 600(0)
- CSAR 62
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- Novolac e-beam resists (AR-N/P 7000)
- Electra 92
The general rule is that with increasing bake- or process temperatures, the solubility of resist films decreases, which consequently results in gradually increasing removal problems. After a bake step above a temperature of 200 °C, resists are inert in the presence of most solvents. Only remover AR 300-70, 300-72 (NMP) and AR 300-73 (TMAH, aqueous-alkaline) still cause film swelling and are in some cases able to remove layers.
PMMA- and styrene acrylate resists:
Easily soluble in: acetone, MEK, PMA (PGMEA), NMP, chlorobenzene, ethylbenzene, anisole, MIBK, ethyl lactate
Not soluble in: water, strong bases, isopropanol, ethanol, nonane, and the like.
CSAR 62
Easily soluble in: chlorobenzene, ethylbenzene, anisole, MEK, hardly soluble in: acetone, MIBK, ethyl lactate
Not soluble in: water, strong alkaline solutions, isopropanol, ethanol, nonane and others.
Novolac resists:
Easily soluble in: acetone, MEK, PMA (PGMEA), NMP, anisole, MIBK, isopropanol, butyl acetate, ethyl lactate, strong acids
Not soluble in: water, ethylbenzene, nonane, and the like.
Electra 92:
Easily soluble in: water
Not soluble in: acetone, MEK, PMA (PGMEA), NMP, anisole, MIBK, isopropanol, butyl-acetate, chlorobenzene, ethylbenzene, nonane, and the like.
Abbreviations of solvents and raw materials used: MEK: methyl ethyl ketone; PMA (= PGMEA): 1-methoxy-2-propyl acetate, NMP: N-methyl-2-pyrrolidone, MIBK: methyl isobutyl ketone, TMAH: tetramethylammonium hydroxide, KOH: caustic potash solution, HF: hydrofluoric acid
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