Coating apparatus – With indicating – testing – inspecting – or measuring means
Reexamination Certificate
2000-04-17
2001-07-17
Bueker, Richard (Department: 1763)
Coating apparatus
With indicating, testing, inspecting, or measuring means
C118S715000, C118S666000, C156S345420
Reexamination Certificate
active
06261372
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates generally to a vacuum process system equipped with a process vessel for carrying out a vacuum process, such as thin-film deposition or etching, for an object to be processed, such as a semiconductor substrate, using a process gas. More specifically, the invention relates to a vacuum process system designed to carry out optical measurement, such as thermometry using a radiation thermometer, of an object to be processed, from the outside via a transparent window provided in a vacuum process vessel.
2. Description of the Related Art
FIG. 4
schematically shows a typical vacuum process system, to which the present invention is applied. This vacuum process system is used for carrying out a vacuum process, such as thin-film deposition or etching, for a substrate S to be processed, such as a semiconductor substrate, using a process gas. In
FIG. 4
, the vacuum process system is equipped with a process vessel
1
for carrying out the vacuum process for the substrate S housed therein, using a process gas.
To the process vessel
1
, a process gas is supplied from a predetermined gas supply means (not shown). The degree of vacuum in the process vessel
1
is held to be a degree of vacuum necessary for the process, by predetermined exhaust means (not shown).
The top of the process vessel
1
is provided with a transparent window
2
. Outside of the transparent window
2
, there is arranged a radiation thermometer (measuring device)
3
for carrying out the thermometry of the substrate S in the process vessel
1
via the transparent window
2
. The radiation thermometer
3
is a kind of optical measuring system for measuring the temperature of an object on the basis of the quantity of thermal radiation from the object.
In the above described conventional vacuum process system, there is the following problem. That is, when the vacuum process, such as thin-film deposition or etching, for the substrate S in the process vessel
1
using the process gas is carried out, the thin-film deposition due to the action of the process gas proceeds on the internal surface of the transparent window
2
facing the interior of the process vessel
1
.
By such progress of the thin-film deposition, the light transmittance of the transparent window
2
gradually decreases to deteriorate the precision of the optical thermometry for the substrate S using the radial thermometer
3
via the transparent window
2
, so that there is the possibility that it is difficult to carry out the optical thermometry.
In particular, when a pre-coat process or the like for previously supplying a process gas into an empty process vessel
1
before the process to form a uniform thin film in the process vessel
1
is carried out in order to stabilize the state of a predetermined thin-film deposition or the like, the deterioration in the light transmittance of the transparent window
2
due to the thin-film deposition occurs from beginning, so that the above described problem becomes even more serious.
SUMMARY OF THE INVENTION
It is therefore an object of the present invention to eliminate the aforementioned problems and to provide a vacuum process system capable of holding the high precision of optical measurement for an object to be processed, using measuring device via a transparent window provided in a process vessel.
In order to accomplish the aforementioned and other objects, according to the present invention, there is provided a vacuum process system comprising: a process vessel, provided with a transparent window, for carrying out a vacuum process for an object, which is housed therein to be processed, using a process gas; and a measuring device, arranged outside of the transparent window, for carrying out an optical measurement for the object in the process vessel via the transparent window, wherein a plurality of micro holes for inhibiting a thin-film deposition are formed in the internal surface of the transparent window facing the interior of the process vessel.
According to such a vacuum process system, the thin-film deposition due to the action of the process gas can be inhibited in a portion, in which the micro holes are formed on the internal surface of the transparent window, so that the deterioration in the light transmittance of the transparent window due to the thin-film deposition can be inhibited. Therefore, the precision of the optical measurement for the object to be processed using the measuring device via the transparent window can be held to be high.
In the above described vacuum process system, each of the micro holes preferably has a dimension so as to cause a microloading effect. By such a microloading effect of the micro holes, the thin-film deposition on the bottoms of the micro holes can be effectively inhibited.
In this case, for example, if each of the micro holes has a diameter of 0.5 &mgr;m or less and if a ratio of a depth to the diameter of each of the micro holes is 5 or more, it is possible to obtain the microloading effect.
The measuring device may be a radiation thermometer for measuring the temperature of the object.
In this case, the process vessel may house therein a reflector having a predetermined reflectance in place of the object during a non-measurement using the radiation thermometer, and the radiation thermometer may comprise: a light emitting device for emitting irradiation light for the reflector during the non-measurement; a detector for detecting the intensity of light reflected from the reflector for the irradiation light emitted from the light emitting device during the non-measurement, and for detecting the quantity of thermal radiation from the object during a measurement; a transmittance calculator for calculating a light transmittance of the transparent window on the basis of the intensity of the irradiation light emitted from the light emitting device, the reflectance of the reflector, and the intensity of the reflected light detected by the detector; a detected value correcting system for correcting the quantity of thermal radiation detected by the detector, using the light transmittance calculated by the transmittance calculator; and a temperature calculator for calculating the temperature of the object on the basis of the quantity of thermal radiation corrected by the detected value correcting system.
In such a vacuum process system, during the non-measurement using the radiation thermometer, the reflector having the predetermined reflectance is housed in the process vessel in place of the object, to be radiated with light emitted from the light emitting device via the transparent window, and the detector detects the intensity of the reflected light from the reflector. Then, the transmittance calculator calculates the light transmittance of the transparent window on the basis of the intensity of the irradiation light emitted from the light emitting device, the reflectance of the reflector, and the intensity of the reflected light detected by the detector.
In addition, during the measurement using the radiation thermometer, the detector detects the quantity of thermal radiation from the object, and the detected value correcting system corrects the quantity of thermal radiation detected by the detector, using the light transmittance calculated by the transmittance calculator. Then, the temperature calculator calculates the temperature of the object on the basis of the quantity of thermal radiation corrected by the detected value correcting system.
That is, even if the above-described transparent window formed with the micro holes is used, it is difficult to completely prevent the deterioration in the light transmittance of the transparent window due to the thin-film deposition. However, if the thermometry is carried out by the above described detected value correcting system and the others in view of the deterioration in the light transmittance of the transparent window, the precision of the thermometry of the object can be held to be higher.
REFERENCES:
patent: 4887548 (1989-12-01),
Bueker Richard
Finnegan Henderson Farabow Garrett & Dunner L.L.P.
Tokyo Electron Limited
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