CN203645903U - A debris collection device and an EUV light source system comprising the collection device - Google Patents

Abstract

The utility model discloses a debris collection device using an electric field and a corresponding EUV light source system. In the utility model, an electrifying device capable of actively charging uncharged debris and a deflection electric field are sequentially arranged on the transmission path of the debris, and the deflection electric field can deflect the moving direction of the charged debris before being collected. The EUV light source system in the embodiment of the present invention includes an EUV radiation generating device, a light collection system and a debris collection device, the EUV radiation device is used to generate EUV light and generate debris at the same time; the debris generating device is placed Between the EUV radiation generating device and the light collection system. The utility model can effectively reduce the pollution of debris to the vacuum system and components, and does not affect the continuous propagation of EUV light.

Description

A debris collection device and an EUV light source system comprising the collection device

technical field

The utility model relates to a debris collection device and an EUV light source system comprising the collection device.

Background technique

Debris such as charged particles will cause great pollution and harm to vacuum chambers and components. Taking the EUV light source system as an example, whether it is a discharge-generated plasma (DPP) light source or a laser-generated plasma (LPP) light source, when the EUV radiation source radiates extreme ultraviolet light, it will entrain a large number of charged particles and electrically neutral particles. and other debris, most of which are charged particle debris pollutants. For example, the current LPP light source with relatively high energy conversion efficiency uses Sn material as the target material. The 1064nm Nd:YAG laser hits the Sn target. If these debris particles travel to the subsequent optical system (such as the EUV light collection mirror) along with the EUV light, they will cause serious pollution and damage to the collection mirror, resulting in a decrease in the reflectivity of the collection mirror. Therefore, effective methods and devices for reducing debris must be used between the EUV light source and the collector mirror to prevent debris from entering the optical system.

For example, the international patent application publication with the publication number WO2009/144609A1 and the name "Debris Mitigation Device" introduces a method of using radial leaf-shaped foils with flowing gas to reduce debris. The debris reduction in this patent document is divided into two parts. Firstly, the air flow opposite to the movement direction of the debris is used to cool the debris, and the debris with smaller volume and lower speed is blocked. The debris passing through the gas barrier is blocked by the radial leaf-shaped metal foil, and part of the debris falls down at zero speed, while the other part adheres to the metal foil. Although this method can effectively block debris, when the number of radial metal foils is small, the debris blocking effect is poor; Facilitates EUV light collection.

In order to solve the problem of large EUV light loss, the leaf-shaped metal foil is removed from the debris blocking device in the international patent application publication with the publication number WO2011/110383A1 and the name "Radiation Source, Lithographic Apparatus and Device Manufacturing Method". , and the buffer gas that blocks debris is changed to hydrogen gas that absorbs less EUV light. In this patent document, the debris collector is designed as a conical shape with a gradually shrinking caliber to limit the amount of debris with the physical shape of the debris collector, and at the same time, the buffer gas hydrogen is used to block the debris through a reasonable gas flow field design. This method can effectively improve the light transmittance, but the debris blocking efficiency is low.

Utility model content

(1) Technical problems to be solved

The utility model proposes a debris collection device capable of charging uncharged debris and changing the movement direction of the debris through a deflection electric field and an EUV light source system containing it, which mainly solves the following problems: one is to effectively reduce the impact of debris on Pollution of vacuum chambers and components, especially for debris with a relatively high content of charged particles; second, it does not affect the propagation of light waves such as EUV light, ensuring a high transmittance for light.

(2) Technical solutions

In order to solve the above technical problems, the utility model proposes a debris collection device, which is used to collect debris propagating in a specific direction. The electric field generating device is used to generate an electric field that deflects the moving direction of the charged debris and collect the deflected debris, wherein the power supply device and the deflecting electric field generating device are sequentially arranged on the debris on the transmission path.

According to a specific embodiment of the present invention, the power supply device includes a high-voltage power supply, an electrode plate pair and a needle point electrode, and the electrode plate pair is composed of two oppositely placed electrode plates, and the two electrode plates are connected by gas source; the high-voltage power supply is used to apply a high voltage between the electrode plate pair and the needle tip electrode, wherein the high voltage is applied to the electrode plate pair and the needle tip electrode and is in the middle of the electrode plate pair When the neutral gas source is passed, the neutral gas source is ionized into charged ions which collide with the uncharged debris, thereby charging the uncharged debris.

According to a specific embodiment of the present invention, the deflection electric field generator includes a positive electrode plate and a negative electrode plate. A voltage is applied to form an electric field.

According to a specific embodiment of the present invention, the length L of the electric field region, the potential difference V applied between the positive and negative electrode plates, the energy Q of the debris particles, the charged amount q of the debris particles and the electric field width satisfy the following formula:

$\mathrm{<span\; class="notranslate">\; L</span>}<span\; class="notranslate">\; ></span>\mathrm{<span\; class="notranslate">\; 2</span>}\mathrm{<span\; class="notranslate">\; D.</span>}<span\; class="notranslate">\; \&times;</span>\sqrt{\mathrm{<span\; class="notranslate">\; Q</span>}<span\; class="notranslate">\; /</span>\mathrm{<span\; class="notranslate">\; wxya</span>}}<span\; class="notranslate">\; .</span>$

According to a specific embodiment of the present invention, the deflection electric field generating device includes a positive electrode plate and a negative electrode plate, the positive electrode plate is in the shape of a circle, the negative electrode plate is in the shape of a ring, and the ring-shaped negative electrode The plate is concentric with the circular positive electrode plate, thereby generating a radial electric field from the center to the circumference.

According to a specific implementation manner of the present invention, the inner diameter of the negative electrode plate is larger than the radius of the incident region of the EUV light.

The utility model also proposes an EUV light source system, including the aforementioned debris collection device.

According to a specific embodiment of the present invention, the EUV light source system further includes an EUV radiation generating device and a light collection system, the EUV radiation device is used to generate EUV light and generate debris at the same time; the debris generating device is placed in the between the EUV radiation generating device and the light collection system; the light collection system is used to collect and converge the EUV light emitted by the EUV radiation source.

According to a specific embodiment of the present invention, the deflection electric field generator includes a positive electrode plate and a negative electrode plate. A voltage is applied to form an electric field, and the length L of the electric field region and the potential difference V applied between the positive and negative electrode plates, the energy Q of the debris particles, the charged amount q of the debris particles and the width of the electric field satisfy the following formula:

$\mathrm{<span\; class="notranslate">\; L</span>}<span\; class="notranslate">\; ></span>\mathrm{<span\; class="notranslate">\; 2</span>}\mathrm{<span\; class="notranslate">\; D.</span>}<span\; class="notranslate">\; \&times;</span>\sqrt{\mathrm{<span\; class="notranslate">\; Q</span>}<span\; class="notranslate">\; /</span>\mathrm{<span\; class="notranslate">\; wxya</span>}}<span\; class="notranslate">\; .</span>$

According to a specific embodiment of the present invention, the deflection electric field generating device includes a positive electrode plate and a negative electrode plate, the positive electrode plate is in a circle shape, the negative electrode plate is in a ring shape, and the ring-shaped negative electrode plate is connected to the The circular positive electrode plates are concentric, so as to generate a radial electric field from the center to the circumference, and the inner diameter of the negative electrode plate is larger than the radius of the incident region of the EUV light.

(3) Beneficial effects

Compared with the previous technology, the debris collection device proposed by the utility model and the EUV light source system including it have the following advantages: First, it can effectively reduce the pollution of debris to the vacuum system and components, especially for charged particles In the debris removal system with relatively high content, the parameters of the collection device can be reasonably set according to the needs, and the debris removal efficiency can reach more than 95%. Second, the debris device does not affect the continued transmission of EUV light, and the EUV light transmittance It almost reaches 100%; thirdly, only the electric field provided by the electrodes can constitute the debris collection device, which has a simple structure, is easy to implement, and is applicable to a wide range of occasions.

Description of drawings

1 is a schematic structural view of an EUV light source system with a debris collection device according to the first embodiment of the present invention;

Fig. 2 is the schematic diagram of the debris collection device of the first embodiment of the utility model;

3A and 3B are respectively a side view and a front view of the deflecting electric field device in the debris collection device of the first embodiment;

Fig. 4 is a schematic diagram of the principle of the debris collection device blocking debris in the first embodiment;

Fig. 5A is a schematic structural view of the deflecting electric field device in the debris collection device of the second embodiment of the present invention;

Fig. 5B is a schematic structural view of the deflecting electric field device in the debris collection device of the third embodiment of the present invention.

Detailed ways

In general, the present invention proposes a debris collection device using an electric field to reduce debris and a corresponding EUV light source system for collecting debris propagating in a specific direction. In the utility model, a charging device capable of actively charging the uncharged debris and a deflection electric field are sequentially arranged on the propagation path of the debris, and the deflection electric field can deflect the movement direction of the charged debris before being collected. The device for reducing debris of the utility model includes the power supply device and a device for generating a deflection electric field and collecting debris. The debris collecting device of the utility model is suitable for both charged and non-charged conditions of debris. Moreover, since the electric field will not block the propagation of light, the present invention is applicable to optical systems, and the device can be arranged in the propagation path of light, such as an EUV light source system.

In order to make the purpose, technical solutions and advantages of the utility model clearer, the utility model will be further described in detail below in combination with specific embodiments and with reference to the accompanying drawings.

FIG. 1 is a schematic structural view of an EUV light source system with a debris collection device according to an embodiment of the present invention. In the EUV light source system, in order to maintain the cleanliness of the subsequent optical system chamber and reduce the damage to the surface of the optical system caused by the debris generated by the EUV radiation source, three problems must be solved: First, when the debris spreads to the optical system It can be effectively removed before; the second is that EUV light can be effectively transmitted while reducing debris, that is, the energy loss of EUV light is small when passing through the debris collection device; Debris, reduce its energy, and reduce the damage to the optical system caused by the heat dissipation of debris.

As shown in FIG. 1 , the EUV light source system 1 of this embodiment mainly includes an EUV radiation generating device 2 , a debris collecting device 4 and a light collecting system 5 . The debris collection device 4 is placed between the EUV radiation generating device 2 and the light collection system 5 . When the EUV radiation generating device 2 is working, the radiation source 3 will emit EUV light 6 and generate debris 7 at the same time. The debris 7 includes electric particles, electrically neutral particles, etc., and most of the charged particles are positively charged particles. electric particles. The debris 7 will propagate towards the light collecting system 5 side, but, due to the existence of the debris collecting device 4, most of these debris will be collected, thus the debris in the direction of debris propagation will be collected effectively removes. In contrast, EUV light 6 passes through the debris collector 4 almost unaffected. The optical collection system 5 is used for collecting and focusing the EUV light emitted by the EUV radiation source 3 . After passing through the optical collection system 5, it is collected and converged at the intermediate focus (Intermediate focus, IF) 9 on the optical axis 8.

In this embodiment, the distance between the EUV radiation source 3 and the debris collection device 4 is d, and d is usually several hundred millimeters, and the collection angle of the EUV light 6 by the optical collection system 5 is θ.

The debris collection device 4 used in this embodiment is shown in FIG. 2 and mainly includes two parts, a power supply device for actively charging uncharged debris and a deflection electric field generating device. Since the debris in the EUV light source includes charged particles and uncharged neutral particles, in order to improve the collection efficiency, the charging device charges the neutral particles in the debris before entering the deflection electric field device. In this embodiment, the gas source passing through the device is mainly ionized into charged ions by the principle of needle discharge. The electrode plate pair 11 includes two opposite electrode plates, and a gas source can be passed between the electrode plates. The high-voltage power supply 10 applies a high voltage V ₀ (V ₀ usually takes 1kV to 10kV) between the needle tip electrode 14 and the electrode plate pair 11, and feeds a neutral gas source into the middle of the electrode plate pair. When the gas passes through a strong electric field, it is ionized into Charged ions12. Continue to move along the direction 13 into the EUV light propagation channel and collide with the debris 7 to charge the neutral debris. Considering that most of the charged particles in the debris are positively charged, a positively charged ion source is used to make the neutral particles in the debris positively charged. In this embodiment, only a kind of device for actively charging neutral debris particles by needle point discharge is listed, and any other devices that can provide ion sources, such as hydrogen ion source generators, etc., can be used as charging neutral particles. Active power-up device.

The deflection electric field generating device of the debris collection device 4 includes a positive electrode plate 15 and a negative electrode plate 17, the positive and negative electrode plates are placed parallel and facing each other at a certain distance, and a voltage is applied between the positive and negative electrode plates at the same time, and the voltage difference V, thus forming an electric field 16 perpendicular to the optical axis 8, debris 7 will be blocked and collected by the force of the electric field after entering the electric field area.

As shown in FIG. 3B , the electric field region 16 of this embodiment is designed as a rectangle. The length L and width D of the electric field region can be determined according to actual needs. The width D is related to the distance d between the debris collection device 4 and the light source and the collection angle θ of the EUV light 6 by the optical collection system 5 . Specifically, in order to ensure that the electric field 16 covers the entire incident region 18 of EUV light, it is required to meet:

D>2d×tan(θ/2).

For example, when the collection angle is 30° and the distance between the debris collection device 4 and the light source is 250 mm, the width D of the electric field area is about 140 mm.

The length L of the electric field region is related to the potential difference V applied between the positive and negative electrode plates 15, 17, the energy Q of the debris particles, the charged amount q of the debris particles and the width D of the electric field. Specifically, in order to ensure that the debris 7 can be collected to the electrode end 17 before moving out of the electric field 16, it is required to meet:

$\mathrm{<span\; class="notranslate">\; L</span>}<span\; class="notranslate">\; ></span>\mathrm{<span\; class="notranslate">\; 2</span>}\mathrm{<span\; class="notranslate">\; D.</span>}<span\; class="notranslate">\; \&times;</span>\sqrt{\mathrm{<span\; class="notranslate">\; Q</span>}<span\; class="notranslate">\; /</span>\mathrm{<span\; class="notranslate">\; wxya</span>}}<span\; class="notranslate">\; .</span>$

For example, for Sn charged particles in the EUV light source system, the carried energy generally reaches the order of keV. If the energy of high-energy ions is 1keV and the potential difference between the positive and negative electrodes is 100kV, the width of the electric field area is about 30mm; if the applied potential difference is 25kV, the width of the electric field area is about 60mm. The applied potential difference V can be reasonably selected according to the actual situation, so that the length L of the electric field region meets the application requirements.

The working process of the debris collection device 4 formed by the electric field is shown in FIG. 4 . The debris 7 emitted by the EUV radiation source 3 includes charged particles, electrically neutral particles, etc., and most of the charged particles are positively charged particles. After these particles enter the debris collection device 4, they first pass through the area formed by the active ion source. Due to the collision, the electrically neutral particles in the debris will be charged with the same nature as the ion source. Most of the debris particles 7 are positively charged when leaving the region where the ion source is formed. The charged particles enter the subsequent deflection electric field and are affected by the electric field 16 . In the embodiment shown in FIG. 4, most of the EUV light source system is positively charged ions, so they will move along the direction 20, and reach the negative electrode plate 17 before the electric field, thereby being collected, and the debris When the particles pass through the electric field area, they will collide with the particle flow moving in the direction of 20 and will be decelerated. After multiple collisions, the speed in the direction of the optical axis 8 will become zero, so they will be collected together with the charged particle flow Negative electrode terminal 17 below. A small number of electrically neutral particles and particles 19 with relatively high speed pass through the deflection electric field area, but because they have been decelerated when passing through the electric field debris collection device, the pollution and damage to the subsequent collection mirror are reduced.

It can also be seen from the above that in the EUV light source system, most of the debris emitted is charged particles, so the electric field debris collection device composed of the active particle charging device and the deflection electric field device proposed by the utility model can effectively prevent the debris from , for debris with a large content of charged particles, the collection efficiency can reach more than 95%. Another advantage of the debris collection device 3 is that the electric field does not affect light, so the transmittance of EUV light is close to 100%.

The debris collection device of the present invention is not limited to the structure shown in Embodiment 1. The debris collection device of the present invention can be a device that can actively charge particles and a device that generates any form of electric field. FIG. 5A and FIG. 5B are schematic structural views of the second and third embodiments of the deflection electric field in the debris collection device of the present invention, respectively, of the debris collection device applied in the EUV light source system.

The deflecting field arrangement of the debris collection device shown in Figure 5A comprises a positive electrode plate 15 and two negative electrode plates 17, 17'. The electrode plates are placed in parallel and the positive electrode plate 15 is arranged between the two negative electrode plates 17, 17', thereby generating an electric field 16 pointing from the middle line to the two sides. It should be noted that the polarities of the positive and negative electrode plates of this embodiment can be interchanged depending on the chargeability of the debris. Compared with the first embodiment, the debris collection device in this embodiment has the advantages of shortening the movement path of debris in the deflecting electric field and increasing the collection probability.

The deflection electric field generator in the debris collection device shown in FIG. 5B can generate a radial electric field. As shown in Figure 5B, the positive electrode plate 15 is in a circle, the negative electrode plate 17 is in a ring shape, and the ring-shaped negative electrode plate 17 is concentric with the circular positive electrode plate 15, thereby producing a circle directed from the center of the circle to the circumference. radiating electric field. The inner diameter of the annular negative electrode plate of the debris collection device is larger than the radius of the incident region 18 of the EUV light. Compared with the parallel electric field of the first and second embodiments, the radial electric field generated by this deflecting electric field device shortens the movement path of the debris in the deflecting electric field as a whole when collecting debris particles randomly distributed in the moving direction. Thereby better collection efficiency. The specific embodiments described above have further described the purpose, technical solutions and beneficial effects of the utility model in detail. It should be understood that the above descriptions are only specific embodiments of the utility model and are not intended to limit the utility model. For new models, any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present utility model shall be included within the protection scope of the present utility model.

Claims (10)

1. a debris collection device, for collecting the chip of propagating towards specific direction, is characterized in that, this debris collection device comprises:

Power-up device, for making uncharged chip charged;

Deflecting electric field generation device, for generation of the electric field that the direction of motion of charged chip is deflected and collect the chip that the described direction of motion deflects, wherein,

This power-up device and deflecting electric field generation device are successively set on the propagation path of described chip.

2. debris collection device as claimed in claim 1, is characterized in that, described power-up device comprise high voltage source, battery lead plate to and needlepoint electrode,

Described battery lead plate, to being made up of two battery lead plates staggered relatively, passes into gas source between these two battery lead plates;

Described high voltage source for described battery lead plate to and needlepoint electrode between apply high voltage, wherein,

Giving described battery lead plate when applying described high voltage and pass into neutral gas source in the right centre of described battery lead plate with needlepoint electrode, this neutral gas source is ionized to charged ion, this charged ion and uncharged chip bump, thereby make described uncharged chip charged.

3. debris collection device as claimed in claim 2, it is characterized in that, described deflecting electric field generation device comprises positive electrode plate and negative electrode plate, the parallel and placement just over the ground separated by a distance of positive and negative electrode plate, making alive between positive and negative electrode plate simultaneously, thus electric field formed.

4. debris collection device as claimed in claim 3, is characterized in that, the electrical potential difference V applying between the length L of described electric field region and positive and negative electrode plate, the energy Q of chip particle, chip particle carried charge q and electric field width meet following formula:

$L>2D\&times;\sqrt{Q/\mathrm{Vq}}.$

5. debris collection device as claimed in claim 2, it is characterized in that, described deflecting electric field generation device comprises positive electrode plate and negative electrode plate, positive electrode plate is a circle, negative electrode plate is an annular, and circular negative electrode plate is concentric with circular positive electrode plate, thereby produce the radial electric field that is pointed to circumference by the center of circle.

6. debris collection device as claimed in claim 5, is characterized in that, the internal diameter of described negative electrode plate is greater than the radius of the incident area of described EUV light.

7. an EUV light-source system, is characterized in that, comprises debris collection device as claimed in claim 1.

8. EUV light-source system as claimed in claim 7, is characterized in that, this EUV light-source system also comprises EUV irradiation generation device and light collecting system,

These EUV irradiation devices, for generation of EUV light, produce chip simultaneously;

This chip generation device is placed between described EUV irradiation generation device and light collecting system;

This light collecting system is collected and converges for the EUV light that described EUV irradiation bomb is sent.

9. EUV light-source system as claimed in claim 8, is characterized in that, described deflecting electric field generation device comprises positive electrode plate and negative electrode plate, parallel and the placement just over the ground separated by a distance of positive and negative electrode plate, making alive between positive and negative electrode plate simultaneously, thus form electric field, and

The electrical potential difference V applying between the length L of described electric field region and positive and negative electrode plate, the energy Q of chip particle, chip particle carried charge q and electric field width meet following formula:

$L>2D\&times;\sqrt{Q/\mathrm{Vq}}.$

10. EUV light-source system as claimed in claim 8, it is characterized in that, deflecting electric field generation device comprises positive electrode plate and negative electrode plate, positive electrode plate is a circle, negative electrode plate is an annular, and circular negative electrode plate is concentric with circular positive electrode plate, thereby produces the radial electric field that is pointed to circumference by the center of circle, and

The internal diameter of described negative electrode plate is greater than the radius of the incident area of described EUV light.

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