Gas discharge laser

FIELD: electricity.

SUBSTANCE: gas discharge laser comprises: a laser chamber filled with a gas mixture, consisting of ceramic material and comprising the first and second electrodes distant from each other and defining the area of discharge between them, a lengthy pre-ionisation unit and a gas circulation system. The first electrode is located near the inner surface of the laser chamber. The set of capacitors, to which a power supply source is connected, is located outside the laser chamber and is connected with the first and second electrodes via electric inputs of the laser chamber and gas permeable return current leads arranged in the laser chamber at both sides of the electrodes. At the same time the laser chamber comprises a ceramic pipe with two end flanges, which are rigidly connected to each other by means of a lengthy fastening system, and the ceramic pipe of the laser chamber has a lengthy niche at the inner side, where at least the first electrode is installed. Parts of the inner surface of the pipe adjoining the niche form guides of gas flow or spoilers arranged upwards and downwards along the flow from the first electrode.

EFFECT: making it possible to increase capacity of radiation and to reduce losses for production of generation energy.

11 cl, 4 dwg

The technical field

The invention relates to a high intensity discharge device, in particular an excimer laser.

The level of technology

Excimer lasers are the most powerful sources of directional radiation in the ultraviolet (UV) range of the spectrum. Depending on the composition of the gas excimer lasers emit at the junctions of different molecules: ArF (193 nm), KrCl (222 nm), KrF (248 nm), XeBr (282 nm), XeCl (308 nm), XeF (351 nm). Lasers at the molecular fluorine (F₂(157 nm) is close to excimer lasers are gas composition and method of pumping. The most efficient, with an efficiency of about 3%, high-energy, up to ~1 j/pulse, and a powerful, up to 600 watts, are KrF and XeCl lasers, found greatest application in various technologies. These include the production of flat LCD and OLED displays, 3D microprocessing of materials, production of high-temperature superconductors by laser ablation, powerful UV lidar. ArF lasers due to the shortest wavelength that allows you to use a reliable quartz optics are widely used in large-scale lithographic production of integrated circuits with a characteristic size of the elements in only several tens of nm.

In accordance with the needs of modern high-performance technology using excimer lasers and their power is constantly increasing. However, increasing energy the radiation power gas discharge excimer lasers has fundamental physical limitations, which if exceeded, the optimal values of energy generation and pulse repetition rate cause a decrease in the efficiency of the laser, reducing the reliability and stability of its work and, ultimately, increase the cost of operation of the laser.

All this determines the urgency of finding solutions to optimize the design and method of operation of an excimer laser, to increase their capacity and reduce the cost of energy generation at various combinations of energy generation and pulse repetition rate.

Known pulse-periodic discharge laser with a low-voltage pre-ionization by corona discharge, United States Patent 6782030, in order to reduce the inductance of the discharge circuit, which ensures high efficiency of the laser, the capacitors connected to the electrodes placed near the high voltage electrode placed on the side wall of the laser chamber. For compatibility with aggressive media laser is proposed to use capacitors with a coating of inert material.

The disadvantage of this technical solution is that the composition of the ceramic capacitors are components, such as solder, which in case of violation of the protective layer when exposed to F₂or HCl will lead to the exit of the condenser and then laser failure. In addition,in the gas laser parasitic breakdown on the surface of the existing ceramic capacitors, designed to operate in electrically rugged environment, does not allow you to charge them up to rated voltage. This dramatically reduces the power stock capacitors when they are placed in the gas medium of the laser, not allowing to achieve high levels of energy generation and laser power.

This lack of stripped gas discharge excimer laser with x-ray pre-ionization kilowatt average power of radiation, in which the high-voltage electrode placed on the long ceramic flange metal laser camera is connected to the additional chamber with electrically durable gas. Laser Focus World, 25, 10, 23, 1989. The laser device and method of generating laser radiation can increase the aperture of the discharge and, accordingly, energy generation and average power of laser radiation. Low inductance discharge circuit required for high efficiency of the laser is achieved by minimizing the thickness of the dielectric flange by reducing the mechanical load on it when the alignment of internal and external pressures.

The disadvantage of this device and method of generating laser radiation is the complexity of its operation and large dimensions, since the presence of x-ray block of preionization mode causes the application is too complex laser camera, the Pope is acnee section which has a track configuration. In addition, the deformation of the laser chamber complex form while filling the high pressure gas can lead to the destruction rigidly mounted on the ceramic flange.

Known one of the most powerful gas discharge excimer laser systems for industrial applications - dual beam laser VYPER, Coherent Inc. ExcimerProductGuide 2011, including hosted on a shared chassis with two identical compact laser, similar to that described in United States Patent 6757315, each of which includes a housing in the form of a metal tube, which is mounted compact ceramic discharge chamber with a long metal flange. On the high-voltage metal ceramic flange cameras installed high-voltage electrode and a block of preionization mode. The method of generating laser radiation provides simultaneous, synchronized pumping of two identical lasers and the combination of two parallel laser beams outside of the laser.

Data device and method provide the laser radiation parameters that fit a range of technological applications at the level of the lasing energy of 1 j/pulse and power of the UV laser 600 watts to each laser with the length of the electrodes is about 1 m

However, a further increase in energy generation laser systems is difficult because of the use in each of its lasers Prigioni the promotion of low-voltage corona discharge and the limited size of the ceramic discharge chamber, installed in a metal housing with a gas circulation system. Since the discharge chamber, the gas flow abruptly changes direction, it is not possible to effectively increase the velocity of the gas in the electrode gap, resulting in limiting the further increase of the repetition frequency of the discharge pulses and the average power of laser radiation.

The closest technical solution, which can be selected as a prototype, is a gas discharge, in particular, excimer laser or the laser at the molecular fluorine, comprising: filled with a gas mixture of the laser chamber, consisting at least partially of a ceramic material and having spaced apart extended first and second electrodes defining a discharge region between the first electrode located near or directly on the inner surface of the laser chamber, at least one extended block of preionization mode for the preionization mode of gas between the first and second electrodes; a gas circulation system for update gas in the discharge region between successive discharge pulses; a set of capacitors that are located outside of the laser chamber and connected to the first and second electrodes through the electrical inputs of the laser chamber and the gas-permeable reverse distributors located in the laser chamber is on both sides of the electrodes; a power source connected to the capacitors for their pulse charge to the breakdown voltage, providing a gas discharge between the first and second electrodes for excitation of the laser gas mixture and a resonator for generating a laser beam. Patent EP 1525646 B1. The method of generating laser radiation includes the implementation of the preionization mode of gas between the first and second electrodes, the pulse charging of the capacitors, the implementation of discharge between the first and second electrodes and generating a laser beam.

In the laser implemented the possibility of increasing the volume of active gas environment to ensure a high uniform level of preionization mode and high speed gas flow between the electrodes. The result is the possibility of increasing energy generation and power repetitively pulsed excimer laser. Extended camera laser includes a cylindrical tube made of ceramics. For the formation of high-speed gas flow in the discharge zone, on both sides of the first electrode located on the inner wall of the cylindrical tube camera, flush with it posted by long ceramic guides the gas stream. Performing laser camera mainly ceramic determines the possibility of achieving high lifetime of the gas mixture is excimer laser, containing such extremely chemically active components as F₂or HCl.

However, to date, failed to realize the manufacture of one-piece high-quality pipes of large dimensions (for example, a diameter of 0.45 m and 1.4 m long) made of ceramics Al₂O₃high (>95%) purity with high physical-chemical properties and the required processing accuracy required for cameras excimer laser. The implementation of the technology of their manufacture requires too much investment. In the prototype there are various options for reduction caused by the gas pressure of the radial component of the mechanical load on the ceramic tube camera, however, the possibility of reducing the longitudinal component of the load is not suggested.

Disclosure of inventions

The objective of the invention is the creation of more powerful compared to the existing discharge, in particular, excimer lasers with different combination of wavelength, energy generation and pulse repetition rate; providing on this basis, the possibility of increasing the pulse repetition rate, energy generation, average output power with a high efficiency of the laser and, in General, reducing the cost of obtaining energy generation.

To solve this problem is proposed discharge, in particular, excimer laser or laser to Molek is popular fluorine, includes: filled with a gas mixture of the laser chamber, consisting at least partially of a ceramic material and having spaced apart extended first and second electrodes defining a discharge region between the first electrode located near or directly on the inner surface of the laser chamber, at least one extended block of preionization mode; a gas circulation system; a set of capacitors that are located outside of the laser chamber and connected to the first and second electrodes through the electrical inputs of the laser chamber and the gas-permeable reverse distributors located in the laser chamber on both sides of the electrodes; a power source connected to the capacitors, in which the laser camera includes a ceramic tube with two end flanges which are rigidly connected to each other through the long, fastening systems, and ceramic tube laser camera is on the inner side extended a niche that has at least the first electrode.

Preferably, on both sides of the first electrode from the outside of the ceramic tube in the wall made distributed along the length of the ceramic tube, with the exception of its end parts, or niches, or cells in which at least partially immersed condenser base is s.

The first electrode may be adjacent their side edges to the inner faces of the niche or is in close proximity to them.

It is preferable that the recess on the inner surface of ceramic tubes along with the first electrode has at least one block of preionization mode.

In some embodiments, the block of preionization mode contains the system of the extended homogeneous sliding discharge on a dielectric surface.

In some embodiments, the block of preionization mode contains a system of formation of corona discharge.

In some embodiments, the first electrode and the second electrode is made of solid and at least one block of preionization mode is installed on the side of one of the two electrodes.

In some embodiments, either the first electrode or the second electrode is made partially transparent, and block the preionization mode is installed on the reverse side of the partially transparent electrode.

It is preferable that the laser contains electrically connected with the block of preionization mode and one of the electrodes of the auxiliary capacitors, the capacitance of which is many times less than the capacitance of the capacitors.

The above-mentioned objects, features and advantages of the invention will become more apparent from the following description and claims.

Brief description of drawings

The invention is aasnaes the accompanying drawings, presented in a form sufficient for understanding the principles of the invention, and in no way limit the scope of the present invention.

In the drawings, the matching elements of the device have the same item numbers.

Figure 1 - cross section of a laser, in which the first electrode is installed in a recess on the inner surface of the ceramic tube laser camera according to the embodiment of the present invention.

Figure 2 is a cross section of the laser, which blocks the preionization mode based on the corona discharge are located on the side of the first electrode in accordance with the embodiment of the present invention.

Figure 3 is a cross section of the laser, in which the preionization mode placed on the reverse side partially transparent first electrode that is installed in a recess, and the capacitors are partially submerged in the long niches on the outer surface of the ceramic tube of the camera in accordance with the invention.

4 is a cross-section of the laser, in which the area of the discharge is located in a recess on the inner surface of the ceramic tube laser camera in accordance with the invention.

Embodiments of the invention.

In accordance with the invention, a gas discharge laser, in particular an excimer laser or the laser at the molecular fluorine, the cross section of which schemati is but shown in figure 1, contains a laser chamber filled with a gas mixture. For excimer laser gas filling the laser chamber at a characteristic pressure range from 2.5 to 5 ATM, is a mixture of inert gases with Halogens, usually F₂or HCl. Laser camera includes a ceramic tube 1, which is placed apart from each other long the first electrode 2 and second electrode 3, which define the discharge region 4 between them. The first electrode 2 is located near or directly on the inner surface of the ceramic tube 1 laser camera. In the laser chamber is also posted at least one extended block of preionization mode 5 for gas preionization mode between the first and second electrodes 2, 3. In a variant of realization of the laser shown in figure 1, one unit of preionization mode 5 located on the side of the second electrode 3 made in the form of a system of forming a sliding discharge on the surface of the dielectric (sapphire) plate 6 covering the initiating electrode 7, with the control electrode 8 located on the surface of the dielectric plate 6. To update the gas in the discharge region between successive discharge pulses in a ceramic tube 1 laser camera also contains a gas circulation system containing diametrically fan 9, water-cooled tube heat exchanger 10, napravlyayus the blades 11 for forming a gas stream.

Ceramic pipe 1 laser camera is on the inner side of the extended niche 12, in which the first electrode 2. Part 13 of the inner surface of the ceramic tube 1 adjacent to the recess 12, in which the first electrode 2, to form spaced upper and downstream from the discharge region 4 guides the gas stream. It is preferable that the first electrode 2 adjacent its side edges to the inner faces 12 niches or is in close proximity to them. The first electrode 2 may be located in a recess 12 is flush with the portions 13 of the inner surface of ceramic tubes adjacent to the recess 12.

Outside of the laser chamber is set distributed along the ceramic tube 1 capacitors 14 connected with the first and second electrodes 2, 3 through a current-conducting buses 15, 16, electrical inlets 17, 18 ceramic tube 1 laser chamber and a gas-permeable reverse the conductors 19, located in the laser chamber on both sides of the electrodes 2, 3. The capacitors 14 connected switching power supply 20 that is intended for their pulse charge to the breakdown voltage, providing a gas discharge between the first and second electrodes to excite the gas mixture of the laser.

In accordance with the invention, laser camera, along with a ceramic tube 1 includes Tarceva the flanges 21, each of which is sealed with a ceramic tube 1. Two of the front flange 21 rigidly connected to each other through the long mounting system 22, made for example in the form of tie beams 22.

Gas discharge laser operates in the following manner. Includes the source of pulse power supply 20 connected to the capacitors 14 located outside the long gas-filled laser camera, which includes a ceramic tube 1, the ends of which are tightly installed flanges 21 fastened together by long fastening systems, such as tie beams 22. Between the control electrode 8 and the triggering electrode 7 systems forming unit preionization mode 5 lit completed sliding discharge on the surface of the extended sapphire plate 6, figure 1. UV radiation auxiliary discharge unit preionization mode 5 pre-ionization of the gas mixture in the discharge region 4 between the first and second electrodes of the laser 2, 3. At the same time by pulse charging of the capacitor 14 to the breakdown voltage, providing a gas discharge in region 4 between the first and second electrodes 2, 3. The energy stored in the capacitor 14, is embedded in the category of low-inductance discharge circuit includes a set of capacitors 14, conductor ø the us 15, 16, the electrical inputs 17, 18 ceramic tube 1 laser chamber and the return conductors 19, located on both sides of the electrodes 2, 3. The discharge provides the excitation of the gas mixture in the discharge region 4, allowing for the generation of the laser beam. When cooled tubes of the heat exchanger 10 high-speed gas flow is provided diametrically fan 9 and guides the gas stream, which includes a rotary blade 11, and the spoilers, formed by the parts 13 and the inner surface of the ceramic tube 1 adjacent to the recess 12 in which is mounted a first electrode, replace the gas in the discharge region 4, the cycle of operation of the laser is repeated. To provide gas flow in the discharge region 4 reverse ducts 19 is made gas-permeable.

Extended along the ceramic tube laser camera mounting system 22 provides a mounting end flanges 21, each of which is loaded tonnage (in the typical range of 4 to 8 tons) force pressure of the gas contained in the laser chamber. The use of the fastening system 24 of the end flanges 21 removes ceramic tube 1 longitudinal component of the mechanical load caused by the pressure of gas on the end flanges. This provides higher reliability of ceramic-laser camera.

Application for the UV preionization mode-sluttishness discharge (figure 1, 3) in the form of extended plasma sheet on the surface of the dielectric (sapphire) 6 allows you to implement a uniform in the discharge region 4 optimally high level of preionization mode due to the possibility of adjusting the energy input in the auxiliary sliding discharge. This ensures a high efficiency of the laser, as the laser beam and the stability of the laser in a long-term mode, which is an advantage of the preionization mode of the given type.

The proposed design of the laser makes it possible to effectively form a high-speed gas flow in the discharge zone. This provides the possibility of increasing the pulse repetition rate and average power of laser radiation. In addition, unlike the prototype, eliminating the need to produce long ceramic guides, as in the prototype, which simplifies the design of the laser.

In embodiments of the laser (figure 2, 3) in the recess 12 on the inner surface of the ceramic tube 1 along with the first electrode 2 has at least one block of preionization mode 5. In embodiments, laser unit/units preionization mode can be located on the side of the first electrode (2) or on the reverse side of the first electrode, the working surface of which is partially transparent (figure 3).

In a variant of the laser 2, a recess 12 on the inner surface of the ceramic TRU is s 1 along with the first electrode 2 on the sides of the first electrode 2 has two identical blocks of preionization mode 5, each of which includes a system of the extended corona discharge. Each system of the formation of corona discharge is made in the form of a dielectric tube 23 made of ceramics Al₂O₃or sapphire, the internal surface of which is combined with a surface placed in the dielectric tube inner electrode 24. The inner electrode 24 from the end of the tube 23 is electrically connected to the opposite electrode 3 laser (connection for simplicity not shown).

In a variant of the laser, shown in figure 2, when a voltage is applied between the first and second electrodes 2, 3 laser automatically corona discharge between the first electrode 2 and the internal electrode 40 block of preionization mode 5 through a dielectric barrier 23. UV radiation of corona discharges on the sides of the first electrode 2 laser performs the pre-ionization of the discharge region 4. Otherwise, the laser operation is carried out as described above.

Use a block of preionization mode, made in the form located on the sides of the first electrode 2 two identical systems of the extended corona discharge (figure 2), allows in some cases to simplify a bit the laser system and to reduce the inductance of the discharge circuit.

In a variant of the device shown in figure 3, the first electrode 2 is made partially transparent due to scale the output window 25 on its surface, perpendicular to the longitudinal axis of the electrode, and a block of preionization mode 5 is installed on the reverse side of the electrode.

This variant of the invention allows to realize a large aperture homogeneous volumetric discharge in a compact low-inductance discharge laser system and high efficiency change of the gas in the discharge region 4.

When installing the unit preionization mode 5 along with the first electrode 2 in a recess 12 on the inner surface of the ceramic tube 1 camera (2, 3) pre-ionization is performed by the first electrode, which usually allows us to simplify the current leads to the block of preionization mode.

In figure 4 each of the two identical systems forming the sliding discharge unit preionization mode 5 is similar to the one shown in figure 1. The use of high-efficiency pre-ionizer in the form of a symmetric system of forming a sliding discharge, located on the sides of the first electrode 2 in the recess 12 of the ceramic tube 1 laser (figure 4), allows for close-uniform volumetric discharge when using a simple solid electrode.

The first electrode 2 in the recess 12 implies the presence of a thickening of the wall of the ceramic tube 1 laser cameras on the sides of the niche 12. This allows reduction of mechanical strength of the ceramic tube to implement variants of the invention, in which on both sides of the PE the first electrode 2 with the outer side of the ceramic tube 1 in its wall made distributed along the length of the ceramic tube laser chambers or niches, or cells 26, figure 3. The capacitor 14 is immersed at least partially in niches/cell 26. Niches 26 differ from cell 26 so that each recess 26 is located at a few capacitors, and in each cell 26 one capacitor 14, so that they differ only in the length and form. By placing in the niches/cell capacitors 26 14 close to the discharge region 4. This reduces the inductance of the discharge circuit and allows to increase the energy of the laser generation without compromising the efficiency of the laser.

In embodiments of the invention illustrated in figure 4, in order to reduce the inductance of the discharge circuit may be even greater approximation of the capacitor 14 to the discharge region 4. In these embodiments, the ceramic tube 1 laser camera is on the inner side of the extended niche 27 such a large volume that it housed not only the first electrode 2, and at least part of the discharge region 4. The inner faces 28, 29 27 niches located on both sides of the discharge region 4, form located up and downstream from the discharge region 4 guides the gas flow, significantly altering the direction of the gas flow when passing through the discharge region. On both sides of the niches 27 from the outside of the ceramic tube 1 in its wall made distributed along the length of the ceramic tube laser niche camera/cell 26, which, at measures which, partially submerged capacitors 14.

Ceramic pipe 1 laser camera can be performed in accordance with different variants of the invention either one-piece or composed of several ceramic modules.

The simplification of the operation of the laser is achieved in embodiments of the invention with automatic pre-ionization. In these embodiments, illustrated in figure 4, the laser contains electrically connected with the block of preionization mode 5 and one of the electrodes of the auxiliary capacitors 30, the capacity of which is many times less than the capacitance of the capacitor 14. 4 blocks of preionization mode 5 are located near the first electrode 2 and the auxiliary capacitor 30 is electrically connected with the first electrode 2 through the auxiliary electrical inputs 31 installed in the wall of the ceramic tube 1 camera along it.

In these embodiments of the laser pre-ionization of the discharge region 4 is performed automatically when the power source 20 through the charging of the auxiliary capacitor 30 through the auxiliary bit interval/intervals unit/units the preionization mode 5. In the process of automatic preionization mode current auxiliary discharge preionization mode 5 flows through a low-inductance discharge circuit that includes the first electrode 2, the auxiliary electrical inputs 31 and auxiliary condensate is ry 30. The small size of the auxiliary capacitor 30 determines optimally small energy input in the auxiliary discharge in the pre-ionizer. This ensures high efficiency of the laser is a great time of life of pre-ionizer, the gas mixture of the laser as a whole. Otherwise, the laser operation is carried out similarly as described above.

Performing laser in specified increases its efficiency.

Thus, the execution of the gas discharge, in particular, an excimer laser in accordance with the invention allows to increase the energy generation, the average radiation power at high efficiency laser and, in General, to reduce the cost of energy generation.

The list of designations

1 - ceramic tube

2 - the first electrode

3 - the second electrode

4 - the area of the discharge

5 is a block preionization mode

6 - dielectric (sapphire) plate

7 - initiating electrode

8 - firing electrode

9 is diametrically fan

10 - tube heat exchanger

11 - directing blades

12 - NIS

13 - part inner surface of the ceramic tube, adjacent to the niche

14 - capacitors

15 - current-carrying bus

16 - electrical inputs

17 - electrical inputs

18 - electrical inputs

19 - reverse distributors

20 is a switching power supply

21 - the endcap

23 - dielectric tube system the formation of corona discharge

24 - the inner electrode of the formation of corona discharge

25 - slit window on the working electrode surface

26 is positioned along the laser camera niche or cells, which are partially immersed capacitors

27 extended niche large amount of

28 is part of the inner surface of the ceramic tube, adjacent to the niche

29 - part of the inner surface of the ceramic tube, adjacent to the niche

30 auxiliary capacitors

31 - auxiliary electrical inputs.

1. Discharge, in particular, excimer laser or the laser at the molecular fluorine, comprising: filled with a gas mixture of the laser chamber, consisting at least partially of a ceramic material and having spaced apart extended first and second electrodes defining a discharge region between the first electrode located near or directly on the inner surface of the laser chamber, at least one extended block of preionization mode; a gas circulation system; a set of capacitors that are located outside of the laser chamber and connected to the first and second electrodes through the electrical inputs of the laser chamber and the gas-permeable reverse the conductors located in the manhole the nuclear biological chemical (NBC camera on both sides of the electrodes; a power source connected to the capacitor, in which the laser camera includes a ceramic tube with two end flanges which are rigidly connected to each other through the long fastening systems, ceramic tube laser camera is on the inner side extended a niche that has at least the first electrode, and a portion of the inner surface of the ceramic tube adjacent to the recess, form located up and down stream from the first electrode guides the gas stream or spoilers.

2. The laser according to claim 1, in which part of the inner surface of the ceramic tube adjacent to the recess, in which the first electrode are flush with the first electrode.

3. The laser according to claim 1, in which the ceramic tube laser camera is on the inner side of the extended niche, which, along with a first electrode placed at least part of the discharge region, and an inner edge niches located on both sides of the discharge region, form located up and downstream from the discharge region guides the gas flow/spoilers, significantly altering the direction of the gas flow when passing through the discharge region.

4. The laser according to any one of claims 1 to 3, in which on both sides of the first electrode from the outside of the ceramic tube in the wall of the implementation of the s distributed along the length of the ceramic tube, with the exception of its end parts, or niches, or cells in which at least partially embedded capacitors.

5. The laser according to any one of paragraphs. 1-3, in which the first electrode is adjacent its side edges to the inner faces of the niche or is in close proximity to them.

6. The laser according to any one of claims 1 to 3, in which in a recess on the inner surface of ceramic tubes along with the first electrode has at least one block of preionization mode.

7. The laser according to any one of items 1-3, in which the preionization mode contains the system of the extended homogeneous sliding discharge on a dielectric surface.

8. The laser according to any one of claims 1 to 3, in which the preionization mode contains a system of formation of corona discharge.

9. The laser according to any one of items 1-3, in which either the first electrode or the second electrode is made partially transparent and block the preionization mode is installed on the reverse side of the partially transparent electrode.

10. The laser according to any one of claims 1 to 3, in which the first electrode and the second electrode is made of solid and at least one block of preionization mode is installed on the side of one of the two electrodes.

11. The laser according to any one of claims 1 to 3, containing electrically connected with the block of preionization mode and one of the electrodes of the auxiliary capacitors, the capacitance of which manifold m is niche of the capacitors.