|The storage temperature given on the label/technical data sheet of each AZ® and TI photoresist ensures the accordance with the individual specifications within the shelf life. However, an optimum storage temperature of 5-10░C often makes it possible to apply the resists beyond the given expiry date. When the resist is refrigerated, its temperature has to be adjusted to room temperature in order to prevent condensed water penetrating the resist which might deteriorate its properties.
All AZ® and TI photo resists are shipped in light shielded bottles and are therefore protected against undesired exposure during transport/storage. However, direct exposure to sunlight should generally be avoided.
MicroChemicals® supplies also 250 and 1.000 ml sales volumes of almost all resists. If nevertheless resist is refilled into other containments, we recommend a two-stage cleaning with i) acetone (removal of organic impurities), and ii) isopropanol (residua-free rinsing of contaminated acetone). The very slowly evaporating isopropyl damages photo resists and must been evaporated completely before filling the bottles. The bottles and materials the resists get in contact with, should only be suitable plastics (e.g. uncoloured Teflon, HD-PE without softeners) or low-sodium glass. Between refilling and resist coating, a waiting period of - depending on the viscosity - up to some hours is necessary, in order to outgas air bubbles that may lead to defects in the resist film.
If the resist must be diluted to achieve a lower viscosity, PGMEA (= AZ® EBR Solvent) is strongly recommended, in order to avoid a too rapid particle formation. When diluting the resist, one has to take care that a rapid mixing is guaranteed in order to avoid a highly-diluted interface of photo resist and solvent.|