The illumination of photomasks by DUV radiation (193 nm and 248 nm) is likely to exceed the work function of the chromium absorber. This would lead to photoelectron generation. However, these low-energy photoelectrons cannot go very far in air at atmospheric pressure. Hence they will remain at the absorber surface briefly before returning. However, the presence of contamination on the absorber surface allows the opportunity for haze-forming reactions, which have been known to be the plague since the quarter-micron generation.

Even quartz suffers some DUV absorption (albeit very little and sometimes ignored). This would explain glass backside reactions with contamination as well.

USPatent 4866328 reports the following work functions:

Al2O3 4.7 eV
SiO2 5.0 eV
ZrO2 5.8 eV

However, the wavelength of 193 nm corresponds to 6.4 eV while 248 nm corresponds to 5.0 eV.