Chemical apparatus and process disinfecting – deodorizing – preser – Chemical reactor – With means applying electromagnetic wave energy or...
Reexamination Certificate
1999-07-15
2003-01-21
Warden, Sr., Robert J. (Department: 1744)
Chemical apparatus and process disinfecting, deodorizing, preser
Chemical reactor
With means applying electromagnetic wave energy or...
C422S292000, C422S003000, C422S062000, C422S082050, C422S082090, C422S082110, C134S001000, C134S001200, C134S001300, C134S018000, C356S239700, C356S239800, C356S432000
Reexamination Certificate
active
06508990
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a substrate treating method and apparatus for subjecting a semiconductor substrate to a required treatment, more specifically to a substrate treating method and apparatus which can perform in-situ monitoring of surface states of a semiconductor substrate at a fabrication site and, based on results of the in-situ monitoring, can control treating conditions or detect the end point of the treatment.
Recently, semiconductor devices have elements increasingly micronized, and are made increasingly three dimensional. This makes it difficult for cleaning solutions to intrude into micronized regions or steep steps or to be replaced there. In consideration of future further micronization, dry cleaning, which uses no chemical liquid is noted.
The dry cleaning is art that radiation, e.g., UV radiation for decomposing or dissociating contaminants is applied to a semiconductor substrate, or active species are introduced while the UV radiation is being applied to thereby decompose and remove the contaminants adhered to the semiconductor substrate. For example, to remove organic contaminants staying on silicon substrates reaction with ozone or oxygen excited by UV radiation is effective. Oxygen molecules are dissociated to oxygen atoms by light of a below 242 nm wavelength. The organic contaminants are oxidized by the oxygen atoms and decomposed into H
2
O, O
2
, CO, Co
2
, etc. of high vapor pressures. Organic bonds, such as C—C, C—H, C—O, etc. can be dissociated by the UV radiation. Thus, the contaminants on the semiconductor substrate can be removed.
Thus, knowing surface states of semiconductor substrates is very important also to control parameters for the dry cleaning, such as an optimum irradiation intensity, wavelength, oxygen amount, etc. Accordingly, a dry cleaning method and apparatus which enable in-situ monitoring of surface states of a semiconductor substrate at the fabrication site and control of operation parameters based on results of the in-situ monitoring are required.
On the other hand, plasma etching technique is widely used in patterning steps for forming device structures on semiconductor substrates. Recently, semiconductor devices have elements increasingly micronized, and are made increasingly three dimensional. This makes it difficult for cleaning solutions to intrude into micronized regions or steep steps or to be replaced there. Under these circumstances, dry cleaning using plasma etching is noted as a cleaning method using no chemical solutions.
Here, the plasma etching is dry etching using reactive gas plasmas and removes substances-to-be-treated mainly by actions of neutral active species.
The plasma etching process is determined by dynamic balance in adsorption, reaction and elimination processes between influxes of radical ions, etc. fed in gas phase and outfluxes from semiconductor substrate surfaces. In the plasma etching process, to set optimum plasma etching conditions and to detect the end point of the plasma etching, it is very effective to know adsorption states, chemical bonding states, structures and thicknesses of reaction layers, etc. of surface states of semiconductor substrates. Accordingly, a plasma etching method and apparatus which enable in-situ monitoring of surface states of a semiconductor substrate at the fabrication site and control of operation parameters based on results of the in-situ monitoring are required.
Thus, knowing surface states of semiconductor substrates is required not only in the dry cleaning and the plasma etching but also in other various sites. Various monitoring methods have been conventionally proposed, and some have been practiced.
Means for monitoring a surface state of a semiconductor substrate by internal multiple reflection of infrared radiation is provided by, e.g., FT-IR (Fourier-transform spectroscopy) apparatus or the special use marketed by Perkin-Elmer Co., U.S.A. For wider applications of the means Graseby Specac Limited, for example, markets various accessories.
In the conventional surface state monitoring method using this means, as exemplified in
FIG. 11A
, a substrate-to-be-treated
102
is cut into, e.g., a 40 mm×10 mm strip, and infrared radiation emitted from an infrared radiation source
104
is passed through the substrate-to-be-treated
102
to monitor states of the substrate surfaces. Otherwise, as exemplified in
FIG. 11B
, a substrate-to-be-treated
102
has the end tapered, and infrared radiation is incident on the end surface of the substrate-to-be-treated
102
to undergo multiple reflection inside the substrate, whereby a surface state of the substrate is monitored. Otherwise, as exemplified in
FIG. 1C
, infrared radiation is incident on a substrate-to-be-treated via a prism
106
positioned above the substrate to undergo multiple reflection inside the substrate, whereby a surface state of the substrate is monitored.
However, these monitoring methods needs cutting a substrate-to-be-treated into strips, additionally processing the substrate-to-be-treated, or disposing a prism above a substrate-to-be-treated. These monitoring methods have not been usable in the in-situ monitoring at site of fabricating semiconductor devices.
Methods of monitoring organic contaminants on semiconductor substrates are known, such as thermal desorption GC/MS (Gas Chromatography/Mass Spectroscopy), APIMS (Atmospheric Pressure Ionization Mass Spectroscopy), TDS (Thermal Desorption Spectroscopy), etc. However, these methods are not suitable to be used in-situ monitoring at site of fabricating semiconductor devices for reasons that these methods cannot directly observe large wafers of, e.g., above 300 mm-diameters which are expected to be developed, and need vacuum ambient atmosphere, and have low throughputs, and other reasons.
As described above, the above-described conventional monitoring methods, which are destructive, are not usable in the in-situ monitoring at site of fabricating semiconductor devices or are not suitable for monitoring large semiconductor wafers. These method are unapplicable not only to the in-situ monitoring of surface states of a semiconductor substrate for controlling operation parameters for the dry cleaning, but also to the in-situ monitoring of surface states of a semiconductor substrate for controlling operation parameters for the plasma etching.
The apparatuses for the above-described conventional dry cleaning and plasma etching includes no suitable means for confirming whether or not each substrate has reached prescribed values in actual steps, so that the dry cleaning and plasma etching are completed after set periods of time or whether all substrates have reached prescribed values. Accordingly, the treatments are not sufficient, and residues are generated, or excessive treatments are performed, damaging the substrates. The excessive treatments are not preferable in view of throughputs.
SUMMARY OF THE INVENTION
An object of the present invention is to provide a substrate treating method and apparatus which enable the in-situ monitoring of surfaces states of a semiconductor substrate at the fabrication site and the control operation parameters based on results of the monitoring, and can detect the end point of the treatment.
The above-described object is achieved by a substrate treating apparatus comprising: a substrate treating means for subjecting a substrate-to-be-treated to a required treatment; a surface state monitoring means including an infrared radiation condensing means for condensing infrared radiation or near-infrared radiation emitted by an infrared radiation source onto an outer peripheral part of the substrate-to-be-treated, an infrared radiation detecting means for detecting the infrared radiation or near-infrared radiation which has undergone multiple reflection inside the substrate-to-be-treated and exited from the substrate-to-be-treated, and an infrared radiation analyzing means for analyzing the infrared radiation or near-infrared radiation detected by the infrared radiation detecting means, th
Endo Michiaki
Maeda Yasuhiro
Miyamoto Nobuo
Niwano Michio
Yoshida Haruo
Advantest Corp.
Muramatsu & Associates
Soubra Imad
Warden, Sr. Robert J.
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