3 April 2008 Particle-free mask handling techniques and a dual-pod carrier
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In EUV lithography, particle-free handling is one of the critical issues because a pellicle is impractical due to its high absorption. To investigate this subject, we have developed a mask protection engineering tool that allows various types of tests to be carried out during the transfer of a mask or blank in air and in vacuum. We measured the number of particle adders during the transfer of a mask blank in a dual-pod carrier and in an RSP200 carrier. We found that the number of particle adders (>=46 nm PSL) to a mask blank in a dual pod is less than 0.01 over the whole process from taking the blank out of the load port in air to putting it in the electrostatic chuck chamber in vacuum. Through various experiments, the number of particle adders during any process using a dual pod was found to be very few and very stable. In contrast, for a naked mask, many particle adders were found in large variations. Below one particle were added in over 80% of experiments on a dual pod and in about 20% of experiments on a naked mask. Based on the test results, we can conclude that the use of dual pod is an excellent particle-free transfer technique.
© (2008) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Mitsuaki Amemiya, Mitsuaki Amemiya, Kazuya Ota, Kazuya Ota, Takao Taguchi, Takao Taguchi, Takashi Kamono, Takashi Kamono, Youichi Usui, Youichi Usui, Tadahiko Takikawa, Tadahiko Takikawa, Osamu Suga, Osamu Suga, } "Particle-free mask handling techniques and a dual-pod carrier", Proc. SPIE 6921, Emerging Lithographic Technologies XII, 69213T (3 April 2008); doi: 10.1117/12.771569; https://doi.org/10.1117/12.771569


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