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Title: A reliable control system for measurement on film thickness in copper chemical mechanical planarization system

Abstract

In recent years, a variety of film thickness measurement techniques for copper chemical mechanical planarization (CMP) are subsequently proposed. In this paper, the eddy-current technique is used. In the control system of the CMP tool developed in the State Key Laboratory of Tribology, there are in situ module and off-line module for measurement subsystem. The in situ module can get the thickness of copper film on wafer surface in real time, and accurately judge when the CMP process should stop. This is called end-point detection. The off-line module is used for multi-points measurement after CMP process, in order to know the thickness of remained copper film. The whole control system is structured with two levels, and the physical connection between the upper and the lower is achieved by the industrial Ethernet. The process flow includes calibration and measurement, and there are different algorithms for two modules. In the process of software development, C++ is chosen as the programming language, in combination with Qt OpenSource to design two modules’ GUI and OPC technology to implement the communication between the two levels. In addition, the drawing function is developed relying on Matlab, enriching the software functions of the off-line module. The resultmore » shows that the control system is running stably after repeated tests and practical operations for a long time.« less

Authors:
; ; ; ; ; ;  [1]
  1. State Key Laboratory of Tribology, Tsinghua University, Beijing 100084 (China)
Publication Date:
OSTI Identifier:
22220228
Resource Type:
Journal Article
Resource Relation:
Journal Name: Review of Scientific Instruments; Journal Volume: 84; Journal Issue: 12; Other Information: (c) 2013 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND TECHNOLOGY; 42 ENGINEERING; ALGORITHMS; CALIBRATION; COMPUTER CODES; CONTROL SYSTEMS; COPPER; EDDY CURRENTS; FILMS; LOCAL AREA NETWORKS; MECHANICAL POLISHING; PROGRAMMING LANGUAGES; THICKNESS

Citation Formats

Li, Hongkai, Qu, Zilian, Zhao, Qian, Tian, Fangxin, Zhao, Dewen, Meng, Yonggang, and Lu, Xinchun. A reliable control system for measurement on film thickness in copper chemical mechanical planarization system. United States: N. p., 2013. Web. doi:10.1063/1.4833396.
Li, Hongkai, Qu, Zilian, Zhao, Qian, Tian, Fangxin, Zhao, Dewen, Meng, Yonggang, & Lu, Xinchun. A reliable control system for measurement on film thickness in copper chemical mechanical planarization system. United States. doi:10.1063/1.4833396.
Li, Hongkai, Qu, Zilian, Zhao, Qian, Tian, Fangxin, Zhao, Dewen, Meng, Yonggang, and Lu, Xinchun. Sun . "A reliable control system for measurement on film thickness in copper chemical mechanical planarization system". United States. doi:10.1063/1.4833396.
@article{osti_22220228,
title = {A reliable control system for measurement on film thickness in copper chemical mechanical planarization system},
author = {Li, Hongkai and Qu, Zilian and Zhao, Qian and Tian, Fangxin and Zhao, Dewen and Meng, Yonggang and Lu, Xinchun},
abstractNote = {In recent years, a variety of film thickness measurement techniques for copper chemical mechanical planarization (CMP) are subsequently proposed. In this paper, the eddy-current technique is used. In the control system of the CMP tool developed in the State Key Laboratory of Tribology, there are in situ module and off-line module for measurement subsystem. The in situ module can get the thickness of copper film on wafer surface in real time, and accurately judge when the CMP process should stop. This is called end-point detection. The off-line module is used for multi-points measurement after CMP process, in order to know the thickness of remained copper film. The whole control system is structured with two levels, and the physical connection between the upper and the lower is achieved by the industrial Ethernet. The process flow includes calibration and measurement, and there are different algorithms for two modules. In the process of software development, C++ is chosen as the programming language, in combination with Qt OpenSource to design two modules’ GUI and OPC technology to implement the communication between the two levels. In addition, the drawing function is developed relying on Matlab, enriching the software functions of the off-line module. The result shows that the control system is running stably after repeated tests and practical operations for a long time.},
doi = {10.1063/1.4833396},
journal = {Review of Scientific Instruments},
number = 12,
volume = 84,
place = {United States},
year = {Sun Dec 15 00:00:00 EST 2013},
month = {Sun Dec 15 00:00:00 EST 2013}
}
  • Chemical mechanical planarization (CMP) is the most widely used planarization technique in semiconductor manufacturing presently. With the aid of in situ measurement technology, CMP tools can achieve good performance and stable productivity. However, the in situ measurement has remained unexplored from a kinematic standpoint. The available related resources for the kinematic analysis are very limited due to the complexity and technical secret. In this paper, a comprehensive kinematic analysis of in situ measurement is provided, including the analysis model, the measurement trajectory, and the measurement time of each zone of wafer surface during the practical CMP process. In addition, amore » lot of numerical calculations are performed to study the influences of main parameters on the measurement trajectory and the measurement velocity variation of the probe during the measurement process. All the efforts are expected to improve the in situ measurement system and promote the advancement in CMP control system.« less
  • A wide range of nano-crystalline, single and multi-component oxide/hydroxide particulates, which may be potentially useful as abrasives for chemical-mechanical planarization (CMP) processes, have been produced using a novel, flow-through hydrothermal technology previously developed at the Pacific Northwest National Laboratory. The process, termed rapid thermal decomposition of precursors in solution (RTDS), converts aqueous feed stock solutions containing metal salts and other thermally activated reactants into suspensions or slurries of nano-crystals (with diameters of generally less than 30 nm) by continuous flow through a heated, high pressure reaction pipe (typically, 200--400 C, 6000--8000 psi). Flow at pressure is maintained using a nozzlemore » at the down-stream end of the reaction tube. Crystallite formation occurs during the solution`s brief residence time (<30 s) in the reaction pipe. Control over crystalline phase and, in some cases, particle morphology can be tailored by selecting the appropriate feed chemistry and processing conditions. Using bench-scale equipment, RTDS is capable of producing nano-crystalline particulate material at rates of up to {approx}500 gm of solids per hour. The RTDS processing and characterization of nano-crystalline zirconium-, titanium-, and iron-based oxide and oxyhydroxide particulates are reviewed.« less
  • Chemical mechanical planarization (CMP) of copper involves removal of surface asperities with abrasive particles and polishing processes. This leads to copper-containing nanoparticles extruded into the solution. We model the diffusion-limited agglomeration (DLA) of such nanoparticles which can rapidly grow to large sizes. These large particles are detrimental because they can participate in polishing, causing scratches and surface defects during CMP. The agglomeration is much slower in the reaction-limited agglomeration process. Under realistic conditions the defect generation probability can increase significantly over time scales of {approx}10 to 20 min from DLA, unless prevented by slurry rejuvenation or process modification measures.
  • In-plane geometrical defects on wafer surfaces following Chemical Mechanical Planarization (CMP) processing in the lateral millimeter range and in vertical dimensions in the nanometer range are of increasing importance. They will become a severe yield limiting factor in the 32 nm generations and below. At the wafer edge these defects are known as edge roll off (ERO). The feasibility of measuring flatness and geometry of bare silicon wafers and patterned wafers from different process steps as e.g. shallow trench isolation (STI) and interconnect metallization was successfully demonstrated using wave front sensing. The used wave front sensing methods were according tomore » Makyoh and Shack Hartmann. The specifications achieved were for the Makyoh method a lateral resolution of 2.4 mm and for Shack Hartmann method 1.1 mm. The vertical resolution was 100 nm for the Makyoh method and 50 nm for the Shack Hartmann method.« less
  • In the chemical mechanical planarization (CMP) process, slurry particle size is important because large particles can cause defects. Hence, selection of an appropriate particle measuring system is necessary in the CMP process. In this study, a scanning mobility particle sizer (SMPS) and dynamic light scattering (DLS) were compared for particle size distribution (PSD) measurements. In addition, the actual particle size and shape were confirmed by transmission electron microscope (TEM) results. SMPS classifies the particle size according to the electrical mobility, and measures the particle concentration (single particle measurement). On the other hand, the DLS measures the particle size distribution bymore » analyzing scattered light from multiple particles (multiple particle measurement). For the slurry particles selected for evaluation, it is observed that SMPS shows bi-modal particle sizes 30 nm and 80 nm, which closely matches with the TEM measurements, whereas DLS shows only single mode distribution in the range of 90 nm to 100 nm and showing incapability of measuring small particles. Hence, SMPS can be a better choice for the evaluation of CMP slurry particle size and concentration measurements.« less