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In order to embody high resolution at 32 nm and below, molybdenum silicide (MoSi) phase shift mask (PSM) is essential material in the ArF lithography process, generally. But some problems reported from for the variation of PSM characteristics like transmittance variation and chemical durability. This change in characteristics is an issue for the yield drop in the semiconductor device manufacturing. So we study the behavior of MoSi PSM thin film in the view point of the ArF laser exposure in this paper. Firstly, the problems of MoSi thin film by the 193 nm exposure are observed. From the result, 0.36 % of the transmittance was changed by 193 nm irradiation with 10 kJ of energy. Accordingly, MoSi thin film characteristics were degraded by the ArF laser irradiation. The reason for the transmittance degradation by irradiation for MoSi thin film was analyzed. Also, we found that the oxygen was activated by the ArF laser and this activated oxygen penetrated to MoSi thin film. Consequently, the transmittance increased by the penetrated oxygen. Then we investigated the improvement scheme for MoSi thin film's irradiation characteristic. First, the transmittance of the thin film was changed by the reactive gas ratio change. Also, the Si ratio in the MoSi thin film was changed. Lastly, densification process was applied. Consequently, the densification process for the MoSi thin film improved the irradiation characteristics.

According to the semiconductor technology roadmap, immersion lithography is emerging for 32 nm and below technology. Therefore, immersion lithography requires new process parameters such as high refractive index fluid, stepper, resist, and birefringence. A lot of research for those items has been done, and the components and materials of thin film used blankmask have become more important. The birefringence of thin film is an especially essential issue for the development of advanced technology. Accordingly, we studied birefringence with thin film characteristics. Having a transmittance of 6% at 193 nm, six different kinds of molybdenum silicon-based thin films were prepared by DC magnetron sputter. The thin films were deposited on 6.3 mm thick quartz using O2, N2, CH4 and CO2 reactive gasses. We studied the effects of thin film composition, substrate, heat treatment, and dopant in this paper. First, we measured the birefringence as thin film composition and substrate by the 250AT Exicor system. We studied the effect of reactive gas flow rate and types on birefringence, and we selected thin film material adaptable to reduce the birefringence from the above results. Next, we doped the transition metal to the selected materials to decrease the birefringence. Then we did heat treatment to the thin films by using rapid thermal process (RTP) to further reduce the birefringence. According to the results, we confirmed that the birefringence was influenced by thin film composition and it was controlled by the tuning of thin film composition, dopants, and heat treatment. Next, we analyzed the intensity of crystal state and density of thin films by using x-ray diffractometer (XRD) and x-ray refractometer (XRR). Finally, we analyzed the thin film characteristics by using various analytic tools.

Positive chemically amplified resist (CAR) is widely used because of its benefit to high resolution in the semiconductor industry. Recent numerous studies have reported that resist pattern error such as resist scum and adhesion fail at the interface between substrate and positive CAR is caused by substrate dependency. Hence resist pattern error must be minimized. In this study we have observed the phenomena at the positive CAR coated mask blanks. And then we applied various surface treatments to the Cr film to minimize resist pattern error. Firstly, resist pattern error was occurred by the substrate dependency in the positive CAR coated mask blanks. We have investigated the root causes of this pattern error, we found that nitrogen radical and OH radical in the Cr film could combine with proton in the positive CAR easily. So various surface treatments were applied to minimize detrimental effects of substrate dependency to the positive CAR. And the behavior of substrate dependency was observed by various analyses to verify the effect of surface treatment method. The results showed that substrate dependency could be controlled by surface treatment in the positive CAR coated mask blanks.

The importance of advanced e-beam writing system and chemically amplified resist (CAR) coated blank is increasing gradually in high-end grade photomask manufacture according to CD embodiment of 90 nm and beyond technology node requiring because of the shrinkage of design rule in the semiconductor industry. However, many studies have been reported that CAR has several troubles and especially, CAR sensitivity change is occurred by airborne molecular contamination (AMC). So, the storage life of CAR coated blank is shortened. This problem may cause the difficulty of high-end grade photomask manufacture because it is hard to secure stable mean to target (MTT) and CD uniformity by sensitivity change, T-top profile and footing profile. Therefore, the purpose of this paper is to investigate the storage life extension for high performance CAR coated blank through improvement of the packing materials. Firstly, a variety of packing materials were collected and the selected packing materials were analyzed by Automatic Thermal Desorption Gas Chromatograph/Mass Spectrometer (ATD GC/MS) and Ion Chromatograph (IC) to examine AMC generated from the packing materials. As a result, molecular condensables such as alcohols, hydrocarbons and fatty acids were detected and molecular acids and molecular bases those are NH 4 +, Cl - , NO x - and SO x - were also detected from the packing materials, respectively. From the above results, we selected the best packing materials which generated the least AMC and the worst packing materials which generated the most AMC. Additionally, we verified photomask process with CAR coated blanks which were packed with those packing materials with post coating delay (PCD) by 50 kV e-beam writing system. In consequence, dose to clear (DTC) showed 4.6 μ C/cm 2 at 0 day PCD for both of the best and the worst packing materials of CAR coated blank. After 90 days PCD, DTC variation was only 0.4 μ C/cm 2 for the best packing materials, but DTC variation of 4.0 μ C/cm 2 showed in the worst packing materials. There was 10 times difference in DTC variation between the best and the worst packing materials. As well as, the CD variation at 0.5 μ m dense line presented less than 5 nm movement for 90 days PCD.

As minimum feature size of device shrink down below 100 nm, the process margin for the mask fabrication reduced dramatically. Mask makers are enlisting equipment and material suppliers in their efforts to achieve wide process margin from existing processes. One of the most promising methods is thinning Cr thickness as low as possible. However, bringing the thin Cr blank into mass production line could cause some problem for advance photomask fabrication using 50 kV electron beam writing tools. In this paper, we verified the feasibility of Cr film ranged from 400 A to 1000 A. The results categorized into two sections. At first, we verified the writing property change with thinning Cr thickness and then investigated the etching characteristics. As a result, we found that Cr thickness don't affect writing properties regardless of Cr thickness. However, the thinner Cr blank represented superior etching characteristics to a conventional one. It showed low etching bias and loading effects. From these results, we concluded the thinner Cr blank could not only make the process wider but also improve the mask quality.