KR20130016802A

KR20130016802A - Apparatus and method for suppling target material

Info

Publication number: KR20130016802A
Application number: KR1020110078926A
Authority: KR
Inventors: 이창윤; 임순규; 박주온; 전진호; 이충재
Original assignee: 삼성전자주식회사
Priority date: 2011-08-09
Filing date: 2011-08-09
Publication date: 2013-02-19

Abstract

A target material supply apparatus according to an embodiment of the present invention is a storage tank for storing a target material, an injection unit for injecting the stored target material into the vacuum chamber, the stored target material to the storage tank to be injected from the injection unit A gas supply unit for supplying a high-pressure gas, a housing having the at least one opening for receiving the injection portion and the discharged target material is discharged, positioned around the injection portion inside the housing, the target having a conductive wiring A sensing unit for detecting leakage of the target material based on a change in current generated by leakage of the material from the injection unit to the conductive wire, and when the leakage detection signal is received from the sensing unit, the gas supply unit is connected to the storage tank. And a control unit for controlling the supply of the high pressure gas.

Description

Target material supply device and method {APPARATUS AND METHOD FOR SUPPLING TARGET MATERIAL}

The present invention relates to a laser producing plasma (LPP) type target material supply device and method, and to a target material supply device and method for supplying a target material to a vacuum chamber in which ultra-ultraviolet light is generated. will be.

In general, the laser output plasma method refers to a method of generating extreme ultraviolet light through a plasma generated by irradiating a drive laser to a target material. The ultra-ultraviolet light source device of this type is composed of a target material supply device, a laser oscillation unit, a collector mirror, a vacuum chamber, and the like. The lasers used here include a CO2 laser, an Nd-Yag laser, Excimer lasers.

On the other hand, the collector mirror collects and reflects ultra-ultraviolet light generated in the vacuum chamber. When the target material leaks from the target material supply device, the collector mirror contaminates the collector mirror, thereby reducing the reflection efficiency and the service life of the collector mirror. Can be dropped.

Conventionally, as a method for preventing this, a method of indirectly checking the leakage of the target material by measuring the pressure in the vacuum chamber, a method of monitoring the movement of the target material through a camera, and the like have been tried.

One aspect of the present invention provides a target material supply device and method for detecting the leakage of the target material directly from the lower side of the injection portion, and when the leakage of the target material is detected to block the supply of the target material.

A target material supply apparatus according to an embodiment of the present invention for this purpose is a storage tank for storing a target material, an injection unit for injecting the stored target material into the vacuum chamber, the storage so that the stored target material is injected from the injection unit A gas supply unit for supplying a high pressure gas to the tank, a housing having the at least one opening for receiving the injection portion and the discharged target material is discharged, located around the injection portion inside the housing, and provided with a conductive wiring A detector for detecting leakage of the target material based on a change in current generated by leakage of the target material from the injection unit to the conductive wire, and the gas supply unit is configured to receive the leakage detection signal from the detection unit. The control unit for controlling to block the supply of the high-pressure gas to It should.

The target material is formed of tin or tin compound.

The target material is formed of lithium or a lithium compound.

The injection unit includes a nozzle, a piezo driver, and a filter.

The storage tank includes a heater for heating or warming the stored target material.

The high pressure gas is formed of at least one material of argon, nitrogen, or helium.

The housing is formed of at least one metal of aluminum, stainless steel, and copper.

The sensing unit includes a substrate formed of at least one material of ceramic, epoxy, polyimide, and glass, and the conductive wire is provided on the substrate.

The storage tank has a discharge port for discharging the high pressure gas, and the control unit controls to discharge the high pressure gas from the discharge port of the storage tank when a leak detection signal is received from the detection unit.

On the other hand, the target material supply method according to an embodiment of the present invention accommodates the injection portion of the target material supply apparatus in a housing having at least one opening for discharging the target material, by placing a conductive wire around the injection portion The leakage of the target material is sensed based on a change in current generated by the target material leaking from the injection unit to the conductive wire, and when the leakage of the target material is detected, supply of the high pressure gas to the storage tank is blocked.

When leakage of the target material is detected, the high pressure gas is discharged from the storage tank.

According to one aspect of the present invention described above, since the housing containing the injection portion prevents leakage of the target material into the vacuum chamber, contamination of the components of the ultra-violet light source device can be prevented. In addition, since the leakage of the target material is detected under the injection unit, the leakage of the target material can be detected more directly and accurately. In addition, if leakage of the target material is detected, the supply of the target material is quickly cut off, thereby preventing the spread of contamination of the components of the ultra-violet light source device.

1 is a view schematically showing a method for generating extreme ultraviolet light by a laser-produced plasma method
2 is a cross-sectional view schematically showing a target material supply device of an extreme ultraviolet light source device;
3 is a cross-sectional view schematically showing a target material supply apparatus according to an embodiment of the present invention
4 is a side view schematically showing a target material leaking from an injection part;
5 is a plan view schematically showing the conductive wiring of the sensing unit according to an embodiment of the present invention;
6 is a plan view schematically showing a conductive line of a sensing unit according to another embodiment of the present invention;
FIG. 7 is a side view schematically illustrating a target material leaking from an injection portion into a conductive wire and solidifying in a pillar shape; FIG.
8 is a block diagram schematically illustrating a method for blocking supply of a target material according to an embodiment of the present invention.
9 is a flowchart schematically showing a target material supply method according to an embodiment of the present invention.

Hereinafter, with reference to the accompanying drawings will be described in detail the present invention.

1 is a view schematically showing a method for generating extreme ultraviolet light by a laser-produced plasma method.

Referring to FIG. 1, the ultra-violet light source device of the laser generation plasma method includes a target material supply device 100, a laser oscillator 200, a collector mirror 300, and a vacuum chamber 400.

The target material supply device 100 supplies a target material 141 used as a source for generating ultra-ultraviolet light. The target material supply device 100 supplies the target material 141 at regular intervals in the vacuum chamber 400, and the target material 141 is generally injected at a high speed of about 50 m / s to 100 m / s. On the other hand, the sprayed target material 141 generally has a state of fine droplets or solid particles contained in the droplets having a diameter of about 10 μm to 50 μm.

The laser oscillator 200 irradiates the laser light 210 to the target material 141 supplied into the vacuum chamber 400. The laser light 210 irradiated from the laser oscillator 200 is irradiated by aiming the target material 141 with a carbon dioxide laser, an end-yag laser, an excimer laser, or the like.

When the irradiated laser light 210 reacts with the target material 141, plasma is generated. Ultraviolet light 410 having a wavelength of about 13.5 nm is generated from the thus-induced plasma. At this time, since the generated ultra-violet light 410 is emitted in all directions, the ultra-violet light 410 is collected and reflected by using the collector mirror 300 located at a distance of about 10 cm to 50 cm from the plasma to expose the exposed portion (not shown). Will be sent to

2 is a cross-sectional view schematically showing a target material supply device of the extreme ultraviolet light source device.

Referring to FIG. 2, the target material supply device 100 includes an injection unit 110 and a storage tank 120.

The injection unit 110 may include, but is not limited to, a nozzle 111, a piezo driver 112, and a filter 113.

The nozzle 111 has an end for receiving the target material 140 from the filter 113 in the form of a micro capillary tube and an end for spraying the target material 140. The inner diameter of the nozzle 111 may vary depending on the diameter of the target material 140, and may be, for example, 10 μm to 50 μm to spray the target material 141 in a fine droplet state. On the other hand, the nozzle 111 may be formed of a silica material having a polyimide coating on the outside so as not to be easily broken.

The piezo actuator 112 is located around the nozzle 111 in a ring or tube shape. The piezo driver 112 forms the target material 140 into a stream of droplets of uniform size while vibrating the nozzle 111 at a constant frequency. In general, the frequency of vibrating the nozzle 111 is several times to several tens of the frequency at which the laser light 210 is irradiated. For example, when the operating frequency of the laser oscillator 200 is 100 kHZ, and the target material supply device 100 forms the target material droplet 141 having a diameter of about 20 μm, the vibration frequency of the piezo driver 112 is About 1 to 2 MHZ.

The filter 113 includes a micro filter and a water filter, and removes impurities and moisture from the target material 140 supplied from the storage tank 120 to supply the nozzle 111.

Although not shown, between the nozzle 111 and the filter 113, the filter 113 and the storage tank 120 may be coupled by fasteners, respectively.

The storage tank 120 stores the target material 140 therein and has a heater 120 on an inner wall thereof. The storage tank 120 may have a cylindrical shape having an inner space to store the target material 140 therein, but is not limited thereto.

The target material 140 is formed of tin, lithium, or a compound thereof having good luminous efficiency, but is not limited thereto. For example, it may be formed of a tin compound such as SnBr4, SnBr2, SnH4 or a tin alloy such as tin-gallium alloy or tin-indium alloy. On the other hand, depending on the characteristics of the target material 140 used is supplied to the vacuum chamber 400 at a temperature of room temperature, above room temperature or below room temperature.

The heater 121 is a heating means for heating or warming the target material 140 stored in the storage tank 120 and located on the inner wall of the storage tank 120. The target material in the storage tank 120 which is solid at room temperature. Melt 140. For example, the heater 121 maintains the temperature in the storage tank 120 at 232 ° C or more, which is the melting point of tin when the target material is tin, or at 186 ° C or more, which is the melting point of lithium when the target material is lithium. At such a temperature, the target material 140 formed of tin, lithium, or a compound thereof is formed of a stable molten metal. The heater 121 may be configured as an electrothermal heater that converts electrical energy into thermal energy, but is not limited thereto.

On the other hand, if the target material 140 formed of solid tin, lithium, or a compound thereof stored in the storage tank 120 reaches the nozzle 111 without being completely melted, it may cause the micro nozzle 111 to be blocked. . Therefore, the solid target material 140 stored in the storage tank 120 needs to have a size and shape that can be completely melted. For example, a spherical target material 140 having a diameter of 2 mm or less may be used.

The target material 140 stored in the storage tank 120 is supplied to the injection unit 110 by the high pressure gas 151 supplied to the storage tank 120, impurities and water are removed from the filter 113, and the nozzle 141 and the piezo driver 112 are formed into droplets 141 and are supplied into the vacuum chamber 400. On the other hand, the injection speed of the target material droplet 141 is controlled by the pressure in the storage tank 120.

Specifically, the high pressure gas 151 is mixed with the target material 140 in the storage tank 120, and the high pressure gas 151 containing the target material 140 is supplied to the injection unit 110. The high-pressure gas 151 is used, for example, inert gas such as argon, nitrogen, helium.

Although not shown, the target material supply device 100 includes a gas supply unit 150 for supplying a high pressure gas 151. The gas supply unit 150 is connected to one side and the other side connected to the injection unit 110 of the storage tank 120 so that the target material 140 is injected from the injection unit 110 so that the high pressure gas ( 151).

3 is a cross-sectional view schematically showing a target material supply apparatus according to an embodiment of the present invention.

Referring to FIG. 3, the target material supply device includes a housing 160 accommodating the injection unit 110 and a detector 170 detecting a leak of the target material 140. Description of the same reference numerals as the target substance supply device of FIG. 2 is omitted.

The housing 160 has an inner space to accommodate the injection unit 110 to which the target material 140 is injected, and the injection unit 110 includes the nozzle 111, the piezo driver 112, and the filter (as described above). 113, but is not limited to such.

The housing 160 may have an inner space through the upper side, the lower side, and the sidewalls, and may be cylindrical, rectangular, or the like, but is not limited thereto. On the other hand, the housing 160 has at least one opening for discharging the target material 141, the injection portion 110 is shielded in all directions except the opening direction by the housing 160. At this time, the opening is formed in the same direction as the injection unit 110, the target material 141 is injected as shown in the figure.

For ease of installation of the housing 160 for the general target material supply device, the housing 160 may be divided into at least two members, and may be installed in the target material supply device through assembly thereof. That is, the housing 160 may be integrally formed with the target material supply device or may be separately assembled and installed at one side of the injection unit 110 of the target material supply device. Meanwhile, an additional inner space for accommodating other components other than the sensing unit 170 may be formed in the inner space of the housing 160.

The housing 160 may have a predetermined thickness to prevent the leaked target materials 142 and 143 from leaking into the vacuum chamber 400, and may have a predetermined size to accommodate the injection unit 110. That is, the size of the housing 160 may vary depending on the outer diameter of the injection unit 110.

On the other hand, the housing 160 may be formed of at least one metal of aluminum, stainless steel, copper in order to accommodate the high-temperature target material (142,143) leaked from the injection unit 110. For example, when the target material 140 is tin, the housing 160 is leaked at a high temperature of 232 ° C or more, which is the melting point of tin. Silver is formed of a metal with high thermal conductivity.

Since the housing 160 accommodates the injection unit 110, the target material 142 and 143 leaks mainly at the coupling site between the nozzle 111 and the filter 113 and between the filter 113 and the storage tank 120. By shielding, the leaked target material 142, 143 may be prevented from leaking into the vacuum chamber 400. That is, the housing 160 can prevent the leaked target material 142, 143 from leaking into the vacuum chamber 400 so as not to contaminate important components inside the vacuum chamber 400.

The sensing unit 170 is accommodated in the inner space of the housing 160 and is positioned around, for example, the lower side of the injection unit 110. The sensing unit 170 is located at least one at a coupling site between the nozzle 111 and the filter 113 in which the target material 140 mainly leaks, and the filter 113 and the storage tank 120.

4 is a side view schematically showing a target material leaking from the injection unit, and FIG. 5 is a plan view schematically showing a conductive line of a sensing unit according to an embodiment of the present invention.

Referring to FIG. 4, the sensing unit 170 includes a conductive line 172 such that the target material 142 is sprayed on the injection unit 110, for example, the nozzle 111 and the filter 113, as shown in FIG. 4. The leakage of the target material 142 is detected on the basis of a change in current generated by leakage into the conductive line 172 of the sensing unit 170 at the coupling portion between the two sides.

The sensing unit 170 includes a substrate 171 for providing conductive wiring, and the substrate 171 has a heat resistance characteristic because the target materials 142 and 143 of high temperature leak onto the substrate 171. Since insulation of the conductive wires and the housing 160 formed of metal must be electrically separated, insulation properties are required. Therefore, the substrate 171 may be formed of a material such as ceramic, epoxy, polyimide, glass, etc. in order to satisfy the above heat resistance and insulation properties, but is not limited thereto.

As described above, the sensing unit 170 detects leakage of the target materials 142 and 143 based on a change in current of the conductive line. As shown in FIG. 5, the conductive line 172 of the sensing unit 170 according to an embodiment is formed of an open circuit through which no current flows.

Referring to FIG. 5, the conductive wires 172 are arranged in the form of a plurality of spaced apart grids to form an open circuit, but the conductive wires 172 arrangement method for forming the open circuit is not limited thereto. On the other hand, although no current flows through the conductive wiring 172 formed as an open circuit, both ends of the conductive wiring 172 spaced apart from each other are connected to a power supply (not shown) for supplying current.

When the target material 142 formed of tin, lithium, or a metal compound thereof leaks from the injection unit 110 to the conductive wire 172 and contacts the conductive wire 172 provided on the substrate 171, the target material 142 of FIG. As shown, the conductive wires 172 spaced apart from each other are electrically connected through the leaked target material 142 to form a closed circuit through which the current 174 flows.

FIG. 6 is a plan view schematically illustrating conductive wires of a sensing unit according to another embodiment of the present invention, and FIG. 7 is a side view schematically illustrating a target material leaking from the spray unit to the conductive wires and solidifying in a pillar shape.

Referring to FIG. 6, the conductive wire 173 provided on the substrate 171 is formed of a closed circuit through which a constant current flows. As shown in FIG. 6, the closed circuit is formed by arranging conductive wires 173 through which a constant current flows under the coupling site where the target material 143 leaks, or by arranging conductive wires 173 to form a closed circuit. The method is not limited thereto and may be arranged in various forms.

Meanwhile, both ends of the conductive wire 173 are connected to a power supply (not shown) that supplies a current so that a constant current flows.

Referring to FIG. 7, the target material 143 formed of tin, lithium, or a metal compound thereof leaks into the conductive wire 173 at the coupling portion between the nozzle 111 and the filter 113, and solidifies in a pillar shape. Can be. For example, when the leaked target material 173 is tin, it leaks from the spraying unit 110 and is exposed to a room temperature of 232 ° C or lower of the melting point of tin, thereby solidifying on the conductive wire 173 or leaking into the conductive wire 173. During the process of solidification to form a solidified pillar form from the leaked coupling site to the conductive wiring 173.

When the leaked target material 143 is solidified in the form of a pillar, a short circuit in which a short circuit current 175 flows by electrically connecting the conductive wire 173 and the coupling portion formed of the metal through the target material 143. Is formed. Meanwhile, one side of the nozzle 111, the filter 113, and the storage tank 120 of the injection unit 110 may be electrically grounded to allow the short circuit current 175 to flow.

8 is a block diagram schematically illustrating a method for blocking supply of a target material according to an embodiment of the present invention.

Referring to FIG. 8, when the leak of the target material 140 is detected, the controller 180 receives a leak detection signal from the detector 170. The controller 180 controls to cut off the supply of the target material 140 of the target material supply device in response to receiving the leak detection signal.

The controller 180 may block the supply of the target material 140 by controlling the gas supply unit 150 to block the supply of the high pressure gas 151 to the storage tank 120. When the supply of the high pressure gas 151 to the storage tank 120 is cut off, the supply of the additional target material 140 is limited because the pressure inside the storage tank 120 does not increase.

On the other hand, the supply of the target material 140 may be cut off through a method of discharging the high pressure gas 151 supplied in the storage tank 120. For this purpose, the storage tank 120 may be provided with an outlet for discharging the high pressure gas 151 although not shown.

The controller 180 controls the high pressure gas 151 to be discharged from the outlet of the storage tank 120 when the target material 140 leakage detection signal is received. If the high pressure gas 151 of the storage tank 120 is not discharged, the supply of the target material 140 may continue until the pressure inside the storage tank 120 is reduced. Therefore, the controller 180 controls an outlet for discharging the high pressure gas 151 to reduce the pressure in the storage tank 120.

The target material supply device may further include a separate storage tank for storing the high pressure gas 151 discharged from the storage tank 120. When the high pressure gas 151 inside the storage tank 120 is discharged into the vacuum chamber 400, important components inside the vacuum chamber 400 may be damaged.

In addition, although not shown, the controller 180 is connected to the coupling portion of the injection unit 110 to detect the short-circuit current 175 flowing through the target material 143 leaked to the conductive wire 173 to leak the target material. Can be detected directly.

9 is a flowchart schematically showing a target material supply method according to an embodiment of the present invention.

Referring to FIG. 9, the injection unit 110 of the target material supply device 100 is accommodated in a housing 160 having at least one opening through which the target material 140 is discharged, and The conductive lines 172 and 173 are positioned below.

The high pressure gas 151 is supplied to the storage tank 120 in which the target material 140 is stored (S10). The target material 140 melted by the heater 121 is mixed with the high pressure gas 151 and supplied to the injection unit 110. Impurities and moisture of the target material 140 are removed from the filter 113, and the target material droplet 141 is formed by the nozzle 141 and the piezo driver 112 and injected into the vacuum chamber 400 (S20). .

The leakage of the target material 140 is sensed based on the change in the current of the conductive wires 172 and 173 positioned below the injection unit 110 (S30). Leakage of the target material 140 forms the conductive wire 172 as an open circuit through which no current flows, and the conductive material 142 leaks from the injection unit 110 to the conductive wire 172. The leaked target material 142 may be detected based on a change in current that is electrically connected and flowed through.

In addition, the leakage of the target material 140 forms the conductive wire 173 as a closed circuit in which a constant current flows, and when the leaked target material 143 solidifies in a pillar shape, the conductive wire 173 is formed of the metal and the conductive wire 173. The coupling portion of the dead part 110 may be detected based on a short circuit current 175 flowing by being electrically connected through the target material 143.

If leakage of the target material 140 is not detected, the target material 140 is continuously sprayed, and if the leakage of the target material 140 is detected, the supply of the target material 140 is blocked (S40).

In order to block the supply of the target material 140, the supply of the high pressure gas 151 to the storage tank 120 is blocked (S50). When the supply of the high pressure gas 151 to the storage tank 120 is cut off, the supply of the additional target material 140 is limited because the pressure inside the storage tank 120 does not increase.

Then, the high pressure gas 151 supplied into the storage tank 120 is discharged (S60). If the high pressure gas 151 inside the storage tank 120 is not discharged, the supply of the target material 140 may continue until the pressure inside the storage tank 120 is reduced, so that the pressure inside the storage tank 120 may be maintained. In order to reduce the high pressure gas 151 is discharged.

100: target material supply device 110: injection unit
111: nozzle 112: piezo actuator
113: filter 120: storage tank
140, 141: target material 142, 143: leaked target material
150: gas supply unit 151: high pressure gas
160: housing 170: sensing unit
171: substrate 172, 173: conductive wiring
180:

Claims

A storage tank for storing the target material;
An injection unit for injecting the stored target material into the vacuum chamber;
A gas supply unit supplying a high pressure gas to the storage tank such that the stored target material is injected from the injection unit;
A housing having at least one opening for receiving the spray and for ejecting the sprayed target material;
A sensing unit positioned around the injection unit inside the housing and having conductive wires to detect leakage of the target material based on a change in current caused by leakage of the target material from the injection unit to the conductive wires; And
And a control unit which controls the gas supply unit to block the supply of the high pressure gas to the storage tank when the leakage detection signal is received from the detection unit.

The method of claim 1,
And the target material is formed of tin or a tin compound.

The method of claim 1,
And the target material is formed of lithium or a lithium compound.

The method of claim 1,
The injection unit target material supply apparatus comprising a nozzle, a piezo driver, a filter.

The method of claim 1,
And said storage tank comprises a heater for heating or warming said stored target material.

The method of claim 1,
And the high pressure gas is formed of at least one material of argon, nitrogen, or helium.

The method of claim 1,
And the housing is formed of at least one metal of aluminum, stainless steel, and copper.

The method of claim 1,
The sensing unit includes a substrate formed of at least one material of ceramic, epoxy, polyimide, and glass, and the conductive wire is provided on the substrate.

The method of claim 1,
The storage tank has an outlet for discharging the high pressure gas,
The control unit is a target material supply device for controlling the high-pressure gas is discharged from the outlet of the storage tank when the leak detection signal is received from the detection unit.

A housing having at least one opening for discharging the target material to receive the injection portion of the target material supply device,
Positioning conductive wires around the sprayer to detect leakage of the target material based on a change in current caused by leakage of the target material from the sprayer to the conductive wires,
And detecting supply of the high pressure gas to the storage tank when leakage of the target material is detected.

The method of claim 10,
Supplying the high pressure gas from the storage tank when leakage of the target material is detected.