Metrology of DSA process using TEM tomography Tamar Segal-Peretz, a,b Jonathan Winterstein, c Jiaxing Ren, a Mahua Biswas, d J. Alexander Liddle, c Jeffrey W. Elam, d Leonidas E. Ocola, e Ralu N. S. Divan, e Nestor Zaluzec, e and Paul F. Nealey. *a,b a Institute for Molecular Engineering, University of Chicago, 5747 South Ellis Ave, Chicago, 60637, USA b Materials Science Division, Argonne National Laboratory, 9700 S. Cass Avenue, Argonne, Illinois 60439, USA c Center for Nanoscale Science and Technology, National Institute of Standards and Technology, 100 Bureau Drive, Gaithersburg, Maryland, 20899, USA d Energy Systems Division, Argonne National Laboratory, 9700 S. Cass Avenue, Argonne, Illinois 60439, USA e Center of Nanoscale Materials, Argonne National Laboratory, 9700 S. Cass Avenue, Argonne, Illinois 60439, USA *Corresponding author: nealey@uchicago.edu Abstract Directed self-assembly (DSA) of block copolymers (BCPs) is a rising technique for sub-20 nm patterning. To fully harness DSA capabilities for patterning, a detailed understanding of the three dimensional (3D) structure of BCPs is needed. By combining sequential infiltration synthesis (SIS) and scanning transmission electron microscopy (STEM) tomography, we have characterized the 3D structure of self-assembled and DSA BCPs films with high precision and resolution. SIS is an emerging technique for enhancing pattern transfer in BCPs through the selective growth of inorganic material in polar BCP domains. Here, Al 2 O 3 SIS was used to enhance the imaging contrast and enable tomographic characterization of BCPs with high fidelity. Moreover, by utilizing SIS for both 3D characterization and hard mask fabrication, we were able to characterize the BCP morphology as well as the alumina nanostructures that would be used for pattern transfer. Keywords: Block copolymers, self-assembly, DSA, TEM, STEM, tomography, 3D characterization, SIS. 1. Introduction Directed self-assembly (DSA) of block copolymers (BCPs) films has been extensively investigated in the past decade for advanced patterning application, with both semiconductors and hard drive manufacturers demonstrating sub-20 nm patterning.[1, 2] The utilization of DSA for the various structures needed for IC manufacturing, for example, line-space, or cylindrical contact patterns, requires control over the three dimensional (3D) structure of the BCP. However, understanding the 3D structure of BCPs is still is an ongoing challenge, mainly due to the lack of metrology techniques capable of accurate, high-resolution, 3D BCP characterization. Currently, the majority of BCP metrology is performed by top-down scanning electron microscopy (SEM) imaging, which provides mainly surface information. Transmission electron microscopy (TEM) tomography, on the other hand, enables characterization of the full 3D structure including domain morphology and defect morphology.[3-5] In TEM tomography of BCPs, one of the main challenges is the poor contrast between the block of most BCPs. To overcome this challenge, BCPs are typically stained using heavy metals, which can create artifacts.[6] Here we show how combining sequential infiltration synthesis (SIS) with angular dark field (ADF) scanning TEM (STEM) tomography can enable high-resolution 3D characterization of both BCP nanostructures and AlO x nanostructures used for pattern transfer, without the use of conventional staining agents. SIS is an emerging technique for enhancing the etch contrast of BCPs by selectively growing inorganic material in one of the BCP domains.[7-9] Infiltration of the precursors into the polymer film in an atomic layer deposition (ALD) tool results in growth of inorganic material, such as Al 2 O 3 , within the film, while the selective interaction of one of the precursor (for example, trimethyl aluminum) with the BCP’s polar domain enables the selective growth. Subsequently, oxygen etching results in an inorganic nanostructure, templated Metrology, Inspection, and Process Control for Microlithography XXIX, edited by Jason P. Cain, Martha I. Sanchez, Proc. of SPIE Vol. 9424, 94240U · © 2015 SPIE CCC code: 0277-786X/15/$18 · doi: 10.1117/12.2085577 Proc. of SPIE Vol. 9424 94240U-1 Downloaded From: http://proceedings.spiedigitallibrary.org/ on 06/12/2015 Terms of Use: http://spiedl.org/terms