Semiconductor device manufacturing: process – With measuring or testing – Electrical characteristic sensed
Reexamination Certificate
2000-04-20
2002-03-12
Nelms, David (Department: 2818)
Semiconductor device manufacturing: process
With measuring or testing
Electrical characteristic sensed
C438S014000, C438S016000, C438S017000, C356S237600
Reexamination Certificate
active
06355495
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a method and an analyzer for analyzing a minute foreign substance present on the surface of a planar sample such as e.g., a silicon wafer for semiconductor element or an insulating transparent substrate for liquid crystal display element, as well as a process for semiconductor elements and liquid crystal display elements by use thereof. More specifically, the invention relates to a method and an apparatus, and semiconductor and liquid crystal display elements by use thereof, in which a minute foreign substance is detected by a particle test unit whose coordinate system is predefined, and by linking the identified position of the minute foreign substance with the coordination system of an analytical unit, it is possible to easily analyze, test and evaluate the identified minute foreign substance.
Analyzers referred to as here mean analyzers for investigating the color tone, stereoscopic image, elemental analysis, chemical structure, crystalline structure and the like by irradiating energy such as light, X-ray, electro-magnetic wave, and various corpuscular beams including electron, neutral chemical species (atom, molecule and such others), ion and phonon to the surface of a sample and detecting a secondary corpuscular beam absorbed or radiated due to the interaction with the sample, or treating the surface of a sample, and include units such functions as analysis, test, estimation and treatment, represented by, for example, Metallographical Microscope, Laser Microscope, Probe Microscope, Inter-Atomic Force Microscope (hereinafter, referred to as AFM), Scanning Tunnel Microscope (hereinafter, referred to as STM), Magnetic Force Microscope (hereinafter, referred to as MFM), Scanning Electron Microscope (hereinafter, referred to as SEM), Electron Probe Micro-Analyzer (hereinafter, referred to as EPMA), X-ray Photoelectron Spectrometer (hereinafter, referred to as XPS), Ultraviolet Photoelectron Spectrometer (hereinafter, referred to as UPS), Secondary Ion Mass Spectrometer (hereinafter, referred to as SIMS), Time of Flight-SIMS (hereinafter, referred to as TOF-SIMS), Scanning Auger Electron Spectrometer (hereinafter, referred to as SAM), Auger Electron Spectrometer (hereinafter, referred to as AES), Reflection High Energy Electron Diffraction Spectrometer (hereinafter, referred to as RHEED), High Energy Electron Diffraction Spectrometer (hereinafter, referred to as HEED), Low Energy Electron Diffraction Spectrometer (hereinafter, referred to as LEED), Electron Energy-Loss Spectrometer (hereinafter, referred to as EELS), Focused Ion Beam Instrument (hereinafter, referred to as FIB), Particle Induced X-ray Emission (hereinafter, referred to as PIXE), Microscopic Fourier Transfer Infrared Spectrometer (hereinafter, referred to as Microscopic FT-IR) and Microscopic Raman, as well as observation units, analytical units, test units and estimation units.
The yield in the production of very highly integrated LSI, represented by
4
M bit- and
16
M bit-DRAM is said to depend almost primarily on defects originating in wafer-adhered foreign substances.
That is because, with finer pattern width, foreign substances of minute size adhered to a wafer in the production process of the previous step, though having so far not been out of the question, becomes the source of pollution. Generally, the size of such minute foreign substances to come into question is said to be on the order of several tenth of the minimum wiring width of very highly integrated LSI to be manufactured, and accordingly minute foreign substances of 0.1 &mgr;m level are the object of examination in 16M bit-DRAM (minimum wiring width 0.5 &mgr;m). Such minute foreign substances form contaminants and cause disconnection or short of a circuit pattern, greatly leading to the occurrence of faults and a decrease in quality and reliability. Thus, it is a key point to the promotion of yield to grasp and control the actual condition of adhesion and the like of minute foreign substances by accurate measurement and analysis.
As means for this operation, there have conventionally been employed particle test devices capable of detecting the location of a minute foreign substance on the surface of a planar sample, such as silicon wafer. The conventional particle test devices include IS-2000 and LS-6000 available from Hitachi Denshi Engineering Ltd.; Surfscan 6200 available from Tencor, USA; WIS-9000 available from Estek, USA or the like. Meanwhile, on the measuring principle employed for these particle test devices and device configuration for implementation thereof, detailed description is seen, for example, in a literature entitled “Analysis/Estimation Technique for High-Performance Semiconductor Process”, pp.111-129, edited by Handotai Kiban Kenkyukai (Semiconductor Substrate Research Group), Realize Ltd.
FIG. 8
shows a display screen of CRT displaying the results measured by using a particle test device LS-6000 for minute foreign substances (0.1 &mgr;m or larger) present on an actual 6-inch silicon wafer. That is, this display screen indicates only the approximate position, the number of foreign substances for each size and the distribution of grain sizes. The circle shown in
FIG. 8
represents the outer periphery of a 6-inch silicon wafer and points present in the circle correspond to the respective locations of minute foreign substances. Incidentally, a particle or a foreign substance described here means any different portion such as a concave, convex, adhered particle or defect, which generates a scattering (irregular reflection) of light.
As seen also from
FIG. 8
, however, the information obtained from a conventional particle test device relates only to the size and location of a minute foreign substance present on the surface of such a sample as silicon wafer, and consequently does not permit one to identify an actual state of the relevant minute foreign substance, such as what it is.
As one example,
FIG. 4
shows the basic configuration of a conventional metallographical microscope with an actuator, one example of conventional metallographical microscope with a positioning function employed for the detection of a minute foreign substance as observed in the IC testing microscopic instrument MODER: IM-120 available from Nidec Co. Ltd. In
FIG. 4
, a sample of silicon wafer
2
is placed on an x-y actuator
1
having a coordinate system roughly linked with that of a particle testing device. The foreign substance
7
detected by the particle testing device is so arranged as to be conveyed to the visual field of a metallographical microscope
3
or the vicinity thereof on the basis of the positional information about the foreign substance obtained from the particle testing device. Hereinafter, the testing procedure and tested results for testing a foreign substance
7
present on the surface of a planar silicon wafer by using a conventional metallographical microscope equipped with actuator.
First, with a plurality of slightly stained mirror-surface ground silicon wafers
2
(CZ (plane orientation:
100
) 6-inch diameter silicon wafer, available from Mitsubishi Material Silicon) is put on a particle test device (Surfscan 6200, available from Tencor Ltd., USA), the approximate size and the approximate location of a foreign substance present on the silicon wafer
2
are observed. At random positions on the silicon wafer
2
, there were about 800 foreign substances in 0.1-0.2 &mgr;m level of diameter, about 130 foreign substances in 0.2-0.3 &mgr;m level of diameter, about 30 foreign substances in 0.3-0.4 &mgr;m level of diameter, about 13 foreign substances in 0.4-0.5 &mgr;m level of diameter, and about 15 foreign substances in 0.5 &mgr;m or more level of diameter. The coordinate system in Surfscan 6200 is so defined that, letting the x- and y-axes (or y- and x-axes) be the direction in contact with the orientation flat (hereinafter, referred to as “orifla”) and its vertical direction in the surface of a wafer, respectively, three points or more of the outermost, except fo
Fujino Naohiko
Karino Isamu
Ohmori Masahi
Wakiyama Shigeru
Yasutake Masatoshi
Berry Renee R.
Hogan & Hartson LLP
Mitsubishi Denki & Kabushiki Kaisha
Nelms David
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