Selective Criteria for Developers
First of all, it has to be checked whether the developer has to be metal ion free (MIF), or alternatively metal ion containing (MIC) developers can be used. Most MIF developers are ready-to-use solutions, while typical MIC developers are supplied as a concentrate which has to be diluted before use.
AZ 326 MIF is 2.38 % TMAH (TetraMethylAmmoniumHydroxide).
AZ 726 MIF is 2.38 % TMAH with surfactants added for fast and homogeneous substrate wetting.
AZ 826 MIF is 2.38 % TMAH with surfactants added for fast and homogeneous substrate wetting, and further additives for removal of resist residuals occasionally remaining after development. These additives, however, slightly increase the dark erosion.
AZ Developer (MIC) is optimized for minimum Al attack. It is typically applied 1 : 1 diluted in DI-water for high contrast, or undiluted for a high development rate. The dark erosion of AZ Developer is slightly higher as compared to other developers.
AZ 351B (MIC) is based on buffered NaOH and typically used in 1 : 4 dilution.
AZ 400K (MIC) is based on buffered KOH and typically used in 1 : 4 dilution.
AZ 303 (MIC) is based on KOH and NaOH and designed for the resist AZ 111 XFS.
The next selection characteristic is the compatibility of the developer to a certain photoresist or/and a certain substrate material (see table below).