X-ray or gamma ray systems or devices – Source – Electron tube
Reexamination Certificate
1999-03-04
2001-05-29
Kim, Robert H. (Department: 2882)
X-ray or gamma ray systems or devices
Source
Electron tube
C378S119000, C378S121000
Reexamination Certificate
active
06240163
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to electromagnetic radiation generators and in particular to X-ray (pulse) generators. Electromagnetic radiation generators find applications in scientific, industrial and medical fields or areas, such as for example, in lithography, in crystallography, in radiography, etc.
BACKGROUND OF THE INVENTION
Known types of electromagnetic radiation generators can be relatively large and relatively costly not only to build but also to maintain and operate; this is especially so if commercial applications are contemplated for a radiation generator.
In the following specific reference will be made by way of example only to X-ray generators however the present invention is not limited thereto; the present invention may, for example, be applied to form an ultra violet light generator, i.e. by providing an ultra-violet light window in place of an X-ray window as described herein.
With respect to X-ray generators, synchrotrons, for example, are relatively large scale known devices which are known for use as X-ray generator devices in commercial environments. Synchrotrons have been described as possible multi-beam X-ray sources for lithography.
Discharge plasma sources have been suggested as possible candidates for a single beam point source for X-rays of relative small size and relatively low cost as compared to the multi-beam approach. Although plasma-based x-ray sources are known which are relatively small in size these have not as yet reached a level of development for commercial purposes in areas such as for example lithography. X-ray sources of this type are, for example, known which comprise an evacuatable discharge chamber an anode, a cathode, a radiation exit port and means for applying a potential as desired between the anode and cathode; see for example European patent specification publication number 0037917. Relatively, small size X-ray generators of this type are also known which exploit a hollow cathode in which the tip of an anode is axially aligned with the passage in the cathode; the presence of the hollow cathode produces beams which are more or less focused; see for example, “X-ray spots emitted in a hollow cathode ns-discharge”, Plasma Sources Sci. Technol. 5 (1996) 70-77 IOP Publishing limited, printed in the UK.
It would be advantageous to have a radiation generator such as an X-ray generator which may be used in sub-micron-lithography.
It would in particular be advantageous to have a radiation source which is simple but which is able to generate short bursts of radiation having maximum intensity for nanometre wavelengths.
SUMMARY OF THE INVENTION
The present invention provides in one aspect in an electrode combination for a radiation head for the generation of electromagnetic radiation comprising
an anode means having a tip end component and
a cathode means,
said tip end component comprising a material able to facilitate, in response to a predetermined pulse voltage applied between said anode means and cathode means, the generation of electromagnetic radiation, the improvement wherein said electrode combination comprises a trigger electrode, said tip end component, said cathode means and said trigger electrode being spaced apart from each other by a respective predetermined distance (i.e. gap).
In accordance with another aspect the present invention provides in a radiation head for the generation of predetermined electromagnetic radiation comprising
a radiation generation chamber,
an anode means having a tip end component, and
a cathode means,
said chamber having a radiation transmitting window of a material preferentially transparent to a predetermined radiation generated in said chamber and through which the predetermined radiation may be emitted from said radiation head, said anode means and cathode means being disposed in said chamber, said tip end component comprising a material able to facilitate, in response to a pulse voltage applied between said anode and cathode, the generation of electromagnetic radiation, the improvement wherein said radiation head comprises a trigger electrode, said tip end component, said cathode means and said trigger electrode being spaced apart from each other by a respective predetermined distance (e.g. gap).
In accordance with yet another aspect of the present invention, there is provided a radiation head for the generation of predetermined electromagnetic radiation including a radiation generation chamber, an anode means having a tip end component, a cathode means, and a trigger electrode. The radiation generation chamber has a radiation-transmitting window of a material preferentially transparent to a predetermined radiation generated in the chamber and through which the predetermined radiation may be emitted from the radiation head. The anode means and the cathode means are disposed in the radiation chamber, while the tip end component of the anode means includes a material able to facilitate, in response to a pulse voltage applied between the anode and the cathode, the generation of electromagnetic radiation.
The tip end component, the cathode means and the trigger electrode are spaced apart from each other by a respective predetermined distance. The improvement characterized in that the radiation head includes capacitor means, for storing electric energy supplied by a high voltage source. The capacitor means includes a terminal electrode for connection to the anode means, and wherein the anode means is directly electrically connected to the terminal electrode of the capacitor means so as to be integral with the capacitor means.
Another feature of the present invention is that the terminal electrode may be disposed in the radiation generation chamber. In another aspect of the present invention, the capacitor means may be disposed within the radiation generation chamber.
The predetermined gap(s) between the anode, cathode and trigger electrode, as well as the relative voltages between the anode, cathode and trigger electrode, may be selected by appropriate experimentation in light of the radiation it is desired to obtain. In any event the closer the trigger electrode is to the cathode the lower the voltage requirements are between the trigger electrode and the cathode, i.e. the closer the trigger electrode is to the cathode the easier for the trigger electrode to facilitate discharge between the anode and cathode. It has been observed for example that the closer the trigger electrode is to the cathode the more reliable and consistent the effect of the trigger is with respect to discharge for a given voltage differential between the cathode and anode.
Thus for example, the trigger electrode may be disposed from 5 &mgr;m to up to 1 mm from the cathode e.g. from the cathode passageway; and the voltage difference between the trigger electrode and cathode may be in the range of voltage from 1 kV to 12 kV, e.g. from 7.5 kV to 10 kV.
The anode tip end component may comprise one or more stem or finger member(s). A stem or finger member may be provided with at least one tip end element. The nature of the material constituting the anode determines for example the spectrum of the X-radiation emitted by the anode. For the purposes of obtaining X-rays the anode tip end element may for example be made of a material able to produce the desired X-ray lines (e.g. for 1.2 nanometers or lower; e.g. for 0.8 to 1.4 nanometers); the anode tip end element material may for example be of tungsten, aluminum, copper, tantalum, molybdenum, or the like including their alloys. Moreover, the anode may as desired or necessary be provided with cooling means using the circulation of an appropriate fluid; please see U.S. Pat. No. 5,651,045.
The material may be chosen for the cathode on the basis of the ease with which it to supply electrons, such as, for example, copper, brass, copper/tungsten or the like,.
If the cathode means comprises a cathode passageway such as for example described herein, the at least one tip end element may be aligned with the cathode passageway. The cathode passageway if present may ha
Drew Stephen
Eich Jacob
Panarella Emilio
Philippe Albert
Zhang Liyan
Advanced Laser & Fusion Technology
Bourque & Associates P.A.
Ho Allen C.
Kim Robert H.
LandOfFree
Radiation E.G. X-ray pulse generator mechanisms does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Radiation E.G. X-ray pulse generator mechanisms, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Radiation E.G. X-ray pulse generator mechanisms will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2500174