Metal etchers

The type of resist material used must meet the requirements for projser image transfer demanded by the printer and for stripping chemistry compatibility. From the metal etcher s point of view, the material needs to provide good adhesion and etch-solution resistance be free of pinholes, oil, or resin bleed-out and be readily removable without damage to substrate... 

The major IH emphasis for dry etchers has been on potential exposures to maintenance personnel working on the reaction chambers, pumps, and other associated equipment that may contain reaction product residues. The complexity of plasma metal etchers and the difficulty in characterizing the odors associated with their maintenance has made them the subject of many investigations and a few published papers. 

The reaction products formed in plasma metal etchers are a complex mixture of chlorinated and fluorinated compounds. The maintenance of metal etchers often involves short duration operations that generate strong odors. Hexachloroethane was found to be the major cause of odor in one type of aluminum etcher.h l In another, cyanogen chloride was the main problem exposure levels were 11 times the 0.3 ppm TLV .[20] In still other types of etchers, hydrogen chloride is associated with the odor (maximum exposure measured was 68 ppm odor threshold for HCl is less than 5 ppm). The paper by Mueller and Kunesh is a good source of additional information on the subject.I l... 

The complexity of the chemistries present in metal etcher exhausts has led researchers to develop experimental methods for investigating the toxicity of these mixtures.Application of these methods in inhalation studies where rats were exposed to etcher effluent six hours per day, five days per week, for four weeks, showed no significant indications of organ toxicity or behavioral effect. There were, however, statistically significant increases in chromosomal aberrations and sister chromatid exchanges in bone marrow cells indicating these chemical mixtures are suspected mutagens. ... 

However, flexible metal foil substrates do not easily process with traditional TFT equipments such as stepper, PECVD, and etchers that are compatible with rigid glass substrates. To utilize traditional TFT equipments, a flexible metal foil substrate can bond to a rigid glass plate. In this case, the adhesive used for bonding the metal foil to a rigid glass plate reduces the maximum process temperature from the value that the substrate itself would withstand. 

Fig. 3 Cross-sectional SEM image of a patterned silicon substrate. By means of micromolding in capillaries (MIMIC), Si was decorated with poly(ferrocen)ddimethylsilane) lines, followed by etching with SFe (3 min) in a cryogenic reactive ion etcher. The organo-metallic polymer residue was removed with nitric acid...

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