Phase imaging results of phase defect using micro-coherent extreme ultraviolet scatterometry microscope

Abstract. To evaluate defects on extreme ultraviolet (EUV) masks at the blank state of manufacturing, we developed a micro-coherent EUV scatterometry microscope (micro-CSM). The illumination source is coherent EUV light with a 140 nm focus diameter on the defect using a Fresnel zone plate. This system directly observes the reflection and diffraction signals from a phase defect. The phase and the intensity image of the defect are reconstructed with the diffraction images using ptychography, which is an algorithm of the coherent diffraction imaging. We observed programmed phase defect on a blank EUV mask. Phase distributions of these programmed defects were well reconstructed quantitatively. The micro-CSM is a very powerful tool to review an EUV phase defect.

[1]  Takeo Watanabe,et al.  Study on Critical Dimension of Printable Phase Defects Using an Extreme Ultraviolet Microscope: II. Definition of Printable Threshold Region for Hole-Pit Programmed Defects , 2010 .

[2]  Kenneth A. Goldberg,et al.  Quantitative evaluation of mask phase defects from through-focus EUV aerial images , 2011, Advanced Lithography.

[3]  T. Bret,et al.  Closing the gap for EUV mask repair , 2012, Advanced Lithography.

[4]  Takeo Watanabe,et al.  Mask observation results using a coherent extreme ultraviolet scattering microscope at NewSUBARU , 2009 .

[5]  J. Rodenburg,et al.  Ptychographic electron microscopy using high-angle dark-field scattering for sub-nanometre resolution imaging , 2012, Nature Communications.

[6]  Takeo Watanabe,et al.  The coherent EUV scatterometry microscope for actinic mask inspection and metrology , 2011, Photomask Japan.

[7]  Pei-yang Yan.  EUVL ML mask blank fiducial mark application for ML defect mitigation , 2009, Photomask Technology.

[8]  Thomas Laursen,et al.  Current status of EUV mask blanks and LTEM substrates defectivity and cleaning of blanks exposed in EUV ADT , 2011, Advanced Lithography.

[9]  Takashi Kamo,et al.  Phase defect printability and actinic dark-field mask blank inspection capability analyses , 2011, Advanced Lithography.

[10]  Takeo Watanabe,et al.  Imaging of extreme-ultraviolet mask patterns using coherent extreme-ultraviolet scatterometry microscope based on coherent diffraction imaging , 2011 .

[11]  Kenneth A. Goldberg,et al.  Printability of native blank defects and programmed defects and their stack structures , 2011, Photomask Technology.

[12]  J. Rodenburg,et al.  A phase retrieval algorithm for shifting illumination , 2004 .

[13]  Takeo Watanabe,et al.  Quantitative phase imaging of a small phase structure on an extreme-ultraviolet mask by coherent diffraction imaging , 2015 .

[14]  K. Midorikawa,et al.  Development of Coherent Extreme-Ultraviolet Scatterometry Microscope with High-Order Harmonic Generation Source for Extreme-Ultraviolet Mask Inspection and Metrology , 2012 .

[15]  Tsuneo Terasawa,et al.  High-speed actinic EUV mask blank inspection with dark-field imaging , 2004, Photomask Japan.

[16]  Tina T. Chan,et al.  Compensation methods for buried defects in extreme ultraviolet lithography masksa) , 2011 .

[17]  O. Bunk,et al.  High-Resolution Scanning X-ray Diffraction Microscopy , 2008, Science.

[18]  Takeo Watanabe,et al.  Phase imaging of EUV masks using a lensless EUV microscope , 2013, Photomask and Next Generation Lithography Mask Technology.

[19]  Takeo Watanabe,et al.  Extreme ultraviolet mask observations using a coherent extreme ultraviolet scatterometry microscope with a high-harmonic-generation source , 2015 .

[20]  Katsumi Midorikawa,et al.  Development of coherent EUV scatterometry microscope with high-order harmonic for EUV mask inspection , 2013, Optics & Photonics - Optical Engineering + Applications.

[21]  Takeo Watanabe,et al.  Defect Characterization of an Extreme-Ultraviolet Mask Using a Coherent Extreme-Ultraviolet Scatterometry Microscope , 2012 .

[22]  Minoru Sakamoto,et al.  Improvement of total quality on EUV mask blanks toward volume production , 2010, Advanced Lithography.

[23]  Takeo Watanabe,et al.  Phase defect characterization on an extreme-ultraviolet blank mask using microcoherent extreme-ultraviolet scatterometry microscope , 2013 .