Measurement and error analysis of Cu film thickness with Ta barrier layer on wafer for CMP application

Accurate thickness measurement of copper (Cu) film on silicon (Si)-based wafers is very important in the chemical mechanical polishing (CMP) process. For thickness measurement of Cu film, the eddy current method is widely adopted due to noncontact, high-efficiency, and high-accuracy characteristics....

Full description

Saved in:
Bibliographic Details
Main Authors: Qu, Zilian, Wang, Wensong, Li, Xueli, Li, Qi, Zheng, Yuanjin
Other Authors: School of Electrical and Electronic Engineering
Format: Article
Language:English
Published: 2022
Subjects:
Online Access:https://hdl.handle.net/10356/159502
Tags: Add Tag
No Tags, Be the first to tag this record!
Institution: Nanyang Technological University
Language: English
id sg-ntu-dr.10356-159502
record_format dspace
spelling sg-ntu-dr.10356-1595022022-06-24T05:28:38Z Measurement and error analysis of Cu film thickness with Ta barrier layer on wafer for CMP application Qu, Zilian Wang, Wensong Li, Xueli Li, Qi Zheng, Yuanjin School of Electrical and Electronic Engineering Engineering::Electrical and electronic engineering Chemical Mechanical Polishing Eddy Current Based Measurement System Accurate thickness measurement of copper (Cu) film on silicon (Si)-based wafers is very important in the chemical mechanical polishing (CMP) process. For thickness measurement of Cu film, the eddy current method is widely adopted due to noncontact, high-efficiency, and high-accuracy characteristics. However, existing thickness measurements of Cu film ignore the effect of tantalum (Ta) barrier layer between Cu film and Si substrate, which makes the measurement result inaccurate. Therefore, it is necessary to investigate the effect of Ta barrier layer on thickness measurement of Cu film. In this article, an improved eddy current sensor system with a nanoscale resolution is proposed. It is based on the inductance-capacitance resonance principle and theoretical analysis is conducted. Several Si-based specimens with pure Cu film, pure Ta film, and Cu-Ta multilayer structure are prepared and measured. Experimental results show that there exists a balance thickness of Ta barrier layer as a threshold in Cu-Ta multilayer structure. When the thickness of Ta barrier layer is larger than the threshold, the measured thickness of Cu film increases with the increase of Ta barrier layer thickness. Conversely, the measured thickness of Cu film decreases when Ta barrier layer is thinner than the threshold. Then, a compensation method is presented, and the error of thickness measurement of Cu film is reduced to less than 6 nm. This work was supported by the Research and Development (R&D) Program of Beijing Municipal Education Commission under Grant KM202010857001. 2022-06-24T05:28:37Z 2022-06-24T05:28:37Z 2020 Journal Article Qu, Z., Wang, W., Li, X., Li, Q. & Zheng, Y. (2020). Measurement and error analysis of Cu film thickness with Ta barrier layer on wafer for CMP application. IEEE Transactions On Instrumentation and Measurement, 70, 8000410-. https://dx.doi.org/10.1109/TIM.2020.3017057 0018-9456 https://hdl.handle.net/10356/159502 10.1109/TIM.2020.3017057 2-s2.0-85097748717 70 8000410 en IEEE Transactions on Instrumentation and Measurement © 2020 IEEE. All rights reserved.
institution Nanyang Technological University
building NTU Library
continent Asia
country Singapore
Singapore
content_provider NTU Library
collection DR-NTU
language English
topic Engineering::Electrical and electronic engineering
Chemical Mechanical Polishing
Eddy Current Based Measurement System
spellingShingle Engineering::Electrical and electronic engineering
Chemical Mechanical Polishing
Eddy Current Based Measurement System
Qu, Zilian
Wang, Wensong
Li, Xueli
Li, Qi
Zheng, Yuanjin
Measurement and error analysis of Cu film thickness with Ta barrier layer on wafer for CMP application
description Accurate thickness measurement of copper (Cu) film on silicon (Si)-based wafers is very important in the chemical mechanical polishing (CMP) process. For thickness measurement of Cu film, the eddy current method is widely adopted due to noncontact, high-efficiency, and high-accuracy characteristics. However, existing thickness measurements of Cu film ignore the effect of tantalum (Ta) barrier layer between Cu film and Si substrate, which makes the measurement result inaccurate. Therefore, it is necessary to investigate the effect of Ta barrier layer on thickness measurement of Cu film. In this article, an improved eddy current sensor system with a nanoscale resolution is proposed. It is based on the inductance-capacitance resonance principle and theoretical analysis is conducted. Several Si-based specimens with pure Cu film, pure Ta film, and Cu-Ta multilayer structure are prepared and measured. Experimental results show that there exists a balance thickness of Ta barrier layer as a threshold in Cu-Ta multilayer structure. When the thickness of Ta barrier layer is larger than the threshold, the measured thickness of Cu film increases with the increase of Ta barrier layer thickness. Conversely, the measured thickness of Cu film decreases when Ta barrier layer is thinner than the threshold. Then, a compensation method is presented, and the error of thickness measurement of Cu film is reduced to less than 6 nm.
author2 School of Electrical and Electronic Engineering
author_facet School of Electrical and Electronic Engineering
Qu, Zilian
Wang, Wensong
Li, Xueli
Li, Qi
Zheng, Yuanjin
format Article
author Qu, Zilian
Wang, Wensong
Li, Xueli
Li, Qi
Zheng, Yuanjin
author_sort Qu, Zilian
title Measurement and error analysis of Cu film thickness with Ta barrier layer on wafer for CMP application
title_short Measurement and error analysis of Cu film thickness with Ta barrier layer on wafer for CMP application
title_full Measurement and error analysis of Cu film thickness with Ta barrier layer on wafer for CMP application
title_fullStr Measurement and error analysis of Cu film thickness with Ta barrier layer on wafer for CMP application
title_full_unstemmed Measurement and error analysis of Cu film thickness with Ta barrier layer on wafer for CMP application
title_sort measurement and error analysis of cu film thickness with ta barrier layer on wafer for cmp application
publishDate 2022
url https://hdl.handle.net/10356/159502
_version_ 1736856416836124672