With the stringent error budget required for sub-130 nm lithography, the development of a low distortion mask is a key concern. Because the global stress field of a thin film layer can introduce distortions in the mask, it is essential that the characteristics of these stress fields be understood and controlled, in order to achieve the high resolution and positioning accuracy required. In this paper, we describe an alternative stress measurement technique that applies the resonant frequency technique (RFT) to stress mapping. Repeatability and uncertainty of the experimental method are discussed. Also, a theoretical analysis of the sensitivity of the stress measurements due to film stack temperature fluctuations was performed. RFT procedures were used to determine the uniformity of the composite film stress across the mask. Tests on the SCALPEL prototype mask identified a radial-type stress gradient. In addition, RFT measurements were used to assess radiation damage of the SiN/Cr/W membrane stack. Preliminary results indicate that the membrane multilayer is essentially insensitive to radiation effects.