Wavelength influence on the determination of subwavelength grating parameters by using optical scatterometry

Lauryna Siaudinyte*, Silvania F. Pereira

*Corresponding author for this work

Research output: Chapter in Book/Conference proceedings/Edited volumeConference contributionScientificpeer-review

42 Downloads (Pure)

Abstract

As the semiconductor industry rapidly approaches the 3nm lithography node, on product overlay (OPO) requirements have become tighter and as a result, residuals magnitude requirements have become even more challenging. Metrology performance enhancements are required to meet these demands. Color Per Layer (CPL) is a unique imaging overlay metrology approach that enables the measurement of each layer with individually-optimized wavelength and focus position. CPL allows the user to custom-define the most suitable conditions per layer, thereby ensuring optimal performance. Imaging-based overlay (IBO) utilizes CPL in order to overcome inaccuracies due to interactions between bottom and top layers. These layers are fundamentally different in that the top grating is usually the photoresist layer, but the bottom grating can be any process layer. Therefore, optimizing the conditions for each layer will maximize measurement accuracy. KLA's Archer™ 700 metrology tool addresses these metrology challenges by putting CPL to use, where the Wave Tuner (WT) allows the user to select a specific wavelength. This paper presents this novel CPL approach and discusses its reduction in OPO and contrast, and reviews use cases from DRAM and 3D NAND. We will present the results from these case studies, focusing on SK Hynix DRAM production wafers.

Original languageEnglish
Title of host publicationProceedings of SPIE
Subtitle of host publicationMetrology, Inspection, and Process Control for Microlithography XXXIV
EditorsOfer Adan, John C. Robinson
PublisherSPIE
Number of pages8
Volume11325
ISBN (Electronic)9781510634176
DOIs
Publication statusPublished - 2020
EventMetrology, Inspection, and Process Control for Microlithography XXXIV 2020 - San Jose, United States
Duration: 24 Feb 202027 Feb 2020

Publication series

NameMETROLOGY, INSPECTION, AND PROCESS CONTROL FOR MICROLITHOGRAPHY XXXIV
ISSN (Print)0277-786X

Conference

ConferenceMetrology, Inspection, and Process Control for Microlithography XXXIV 2020
Country/TerritoryUnited States
CitySan Jose
Period24/02/2027/02/20

Keywords

  • Coherent Fourier scatterometry
  • Coherent light
  • Far field
  • Grating parameters
  • Near field
  • Optical scatterometry
  • Sensitivity
  • Subwavelength grating

Fingerprint

Dive into the research topics of 'Wavelength influence on the determination of subwavelength grating parameters by using optical scatterometry'. Together they form a unique fingerprint.

Cite this