TW201914370A - Extreme ultraviolet lithography apparatus, target material supply system and method - Google Patents

Abstract

A target material supply system is provided, including a target droplet generator, a target droplet catcher, and a target material handling device. The target droplet generator is configured to generate a plurality of target droplets which may be used in an extreme ultraviolet lithography apparatus to generate an extreme ultraviolet. The target droplet catcher is configured to collect unused portions of the target droplets. The target material handling device is configured to supply a target material in a molten state to the target droplet generator, and is configured to re-supply the unused portions of the target droplets recovered from the target droplet catcher to the target droplet generator.

Description

 Extreme ultraviolet lithography equipment, target material supply system and method  

Embodiments of the present invention relate to a semiconductor technology, and more particularly to an extreme ultraviolet (EUV) lithography apparatus and a target material supply system and method thereof.

In recent years, semiconductor integrated circuits have experienced exponential growth. In the advancement of integrated circuit materials and design techniques, multiple generations of integrated circuits have been produced, each of which has smaller and more complex circuits than the previous generation. In the development of an integrated circuit, when the geometric size (that is, the smallest component or line that can be produced in the process) is reduced, the functional density (that is, the number of interconnects per wafer area) is usually increase. In general, such a reduced size process provides the benefit of increased production efficiency and reduced manufacturing costs. However, such a reduced size process also increases the complexity of manufacturing and manufacturing integrated circuits.

For example, the need to use higher resolution lithography processes has grown. One lithography technique is called extreme ultraviolet lithography (EUVL), which utilizes an extreme ultraviolet (EUV) scanner that uses a wavelength range of about 1-100 nm. Since extreme ultraviolet light is easily absorbed by various substances, it is impossible to use a refractive optical system such as a known photolithography technique using visible light or ultraviolet light, so that reflection is adopted in an extreme ultraviolet lithography apparatus. Optical system, that is, reflective reticle and mirror. An extreme ultraviolet light source uses a laser-produced plasma (LPP) technique that focuses a high-power laser beam onto a tiny tin-doped droplet target to form a highly ionized The plasma, in turn, emits extreme ultraviolet light having a wavelength of about 13.5 nm from a highly ionized plasma.

Although the existing extreme ultraviolet lithography technology and equipment are sufficient to meet their needs, they are still not fully met. Therefore, there is a need to provide a solution for improving the extreme ultraviolet photolithography process.

The present disclosure provides a target material supply system including a target droplet generator, a target droplet collector, and a target material processing device. The target droplet generator is configured to generate a plurality of target droplets for use by an extreme ultraviolet lithography apparatus to generate extreme ultraviolet light. The target droplet collector is configured to collect unused portions of the target droplets described above. The target material processing apparatus is configured to supply one of the target materials in a molten state to the target droplet generator, and configured to resupply the unused portion of the target droplet recovered from the target droplet collector To the target droplet generator.

Some embodiments provide an extreme ultraviolet lithography apparatus including a light source chamber, a target droplet generator, a laser light source, a concentrating mirror, a target droplet collector, and a target material. Processing device. The target droplet generator is configured to generate a plurality of target droplets in the source chamber. The laser source is configured to produce a laser beam that is used to excite the target droplets to produce extreme ultraviolet light. A concentrating mirror is disposed in the light source chamber for collecting extreme ultraviolet light. The target droplet collector is configured to collect the unused portion of the target droplets described above. The target material processing device is disposed outside the light source chamber, configured to supply one of the target materials in a molten state to the target droplet generator, and configured to recover the target droplets to be recovered from the target droplet collector The unused portion is re-supplied to the target droplet generator.

The present disclosure provides a method of supplying a target material, comprising supplying a target material in a molten state to a target droplet generator by a target material processing device. The above method for supplying a target material further comprises generating a plurality of target droplets by a target droplet generator, and the target droplets are used by an extreme ultraviolet lithography apparatus to generate extreme ultraviolet light. The above method of supplying a target material also includes collecting an unused portion of the target droplet by a target droplet collector. Further, the above target material supply method includes re-supplying the unused portion of the target droplet recovered from the target droplet collector to the target droplet generator by the target material processing device.

10‧‧‧ lithography equipment

12‧‧‧Light source

14‧‧‧Lighting optical system

16‧‧‧mask table

18‧‧‧Photomask

20‧‧‧Projection optical system

22‧‧‧Semiconductor substrate

24‧‧‧ substrate table

26‧‧‧ gas supply module

30, 30'‧‧‧ Target material supply system

60‧‧‧Target material supply method

61-64‧‧‧ operation

121‧‧‧Target Droplet Generator

121A‧‧‧ Target Droplets

121B‧‧‧Unused part of the target droplet / recovered target droplet

1210‧‧‧Drop storage tank

1211‧‧‧ nozzle

1212‧‧‧heater

1213‧‧‧ Pressure controller

1214‧‧‧Level sensor

1215‧‧‧Level sensor

122‧‧‧Laser light source

123‧‧‧Photoscope

123A‧‧‧Window

124‧‧‧Target Drop Collector

1240‧‧‧ collection trough

1241‧‧‧Connecting pipe/second connecting pipe

1242‧‧‧Valve

1243‧‧‧heater/second heater

1244‧‧‧ Pressure controller / second pressure controller

1245‧‧‧Level sensor

1246‧‧‧Filter/second filter

125‧‧‧Light source chamber

301‧‧‧Target material processing device

3010‧‧‧ storage tank

3011‧‧‧Connecting pipe/first connecting pipe

3012‧‧‧Valve

3013‧‧‧heater/first heater

3014‧‧‧ Pressure controller / first pressure controller

3015‧‧‧Level sensor

3016‧‧‧Filter/first filter

L‧‧‧Laser beam

M1‧‧‧ solid target material

M2‧‧‧ Target material / target material in molten state

P1‧‧‧Excitation zone

P2‧‧‧ second focus

R‧‧‧ Extreme ultraviolet light

Figure 1 is a schematic illustration of a lithography apparatus having an extreme ultraviolet light source in accordance with some embodiments.

Figure 2 is a schematic illustration of the extreme ultraviolet light source of the lithography apparatus of Figure 1.

Figure 3 is a schematic illustration of a target material supply system in accordance with some embodiments.

Fig. 4A is a cross-sectional view taken along line A-A of Fig. 3.

Fig. 4B is a cross-sectional view taken along line B-B of Fig. 3.

Figure 5 is a schematic illustration of a target material supply system in accordance with some embodiments.

Figure 6 is a flow diagram of a method of supplying a target material in accordance with some embodiments.

The following disclosure provides many different embodiments or examples to implement various features of the present invention. The following disclosure sets forth specific examples of various components and their arrangement to simplify the description. Of course, these specific examples are not intended to be limiting. For example, if a first feature is formed on or above a second feature, it may mean that the first feature is directly in contact with the second feature, and may include additional features. Formed between the first feature and the second feature described above such that the first feature and the second feature are not in direct contact with each other.

Spatially related terms used in the following, such as "below," "below," "lower," "above," "higher," and the like, are used to facilitate the description. The relationship between one element or feature and another element or feature(s). In addition to the orientation depicted in the drawings, these spatially related terms are also intended to encompass different orientations of the device in use or operation. The device may be turned to a different orientation (rotated 90 degrees to other orientations), and the spatially related terms used herein may also be interpreted the same.

In addition, the same component numbers and/or characters may be repeated in the following various embodiments, which are not intended to limit the specific embodiments and/or structures discussed. In the drawings, the shape or thickness of the structure may be enlarged to simplify or facilitate the marking. It is to be understood that elements not specifically described or illustrated may be in various forms well known to those skilled in the art.

1 is a schematic diagram of a lithography apparatus 10 in accordance with some embodiments. The lithography apparatus 10 is one of the scanners that can perform a lithography exposure process. According to some embodiments, the lithography apparatus 10 is an extreme ultraviolet lithography apparatus that exposes a photoresist layer (not shown) under extreme ultraviolet light (EUV). The photoresist layer has a material sensitizable to extreme ultraviolet light and is coated on a semiconductor substrate 22. The semiconductor substrate 22 is a semiconductor wafer such as a wafer or other wafer to be patterned. The lithography apparatus 10 uses a light source 12 (also known as an extreme ultraviolet light source) to produce extreme ultraviolet light having a wavelength range between about 1 nanometer and 100 nanometers. In some particular embodiments, source 12 can produce extreme ultraviolet light having a center wavelength of about 13.5 nanometers. The mechanism for generating extreme ultraviolet light from source 12 will be further described in later paragraphs.

The lithography apparatus 10 also includes an illumination system 14 that is a lens system including a plurality of reflective optical elements that can be used to guide the extreme ultraviolet light generated by the light source 12 to a mask stage. ) 16 on one of the reticle 18. According to some embodiments, the reticle stage 16 is capable of stabilizing one of the reticle 18 electrostatic chucks or otherwise securing a reticle stage of the reticle 18. According to some embodiments, the reticle 18 is a reflective reticle comprising reflective multilayers deposited on a substrate. The reflective multilayer comprises a plurality of film pairs, such as a molybdenum-ruthenium film pair, a molybdenum-ruthenium film pair, or other suitable material that is highly reflective of extreme ultraviolet light. The mask 18 further includes a reflective layer deposited on the reflective multilayer and patterned to define a circuit layer of an integrated circuit.

The lithography apparatus 10 further includes a projection optical system 20 for transferring (reflecting) the circuit pattern of the reticle 18 to the photoresist layer on the semiconductor substrate 22. According to some embodiments, projection optical system 20 is a lens system that includes a plurality of reflective optical elements. In addition, the semiconductor substrate 22 is fixed to one of the substrate stages 24 of the lithography apparatus 10. The substrate stage 24 is, for example, a stepper that can control the exposure position of the semiconductor substrate 22, but is not limited thereto.

With the above configuration, the lithography apparatus 10 can selectively expose the photoresist layer on the semiconductor substrate 22 according to the pattern defined by the mask 18 (that is, perform a lithography exposure process). According to some embodiments, lithography apparatus 10 also includes other modules. For example, lithography apparatus 10 can include a gas supply module 26 configured to provide hydrogen to light source 12 to help reduce contamination in light source 12.

Figure 2 is a schematic illustration of the light source 12 of the lithography apparatus 10 of Figure 1. According to some embodiments, the light source 12 is a laser-generated plasma (LPP) extreme ultraviolet light source that focuses a high-power laser beam onto a tiny droplet target to excite the droplet target to form a high ion. Plasma, which in turn emits extreme ultraviolet light from highly ionized plasma.

As shown in FIG. 2, the light source 12 includes a target droplet generator 121, a laser source 122, a collector 123, a target droplet collector 124, and a light source for housing the above components. Chamber 125. In general, in the process of generating extreme ultraviolet light, the light source chamber 125 is maintained in a vacuum state to prevent the extreme ultraviolet light from being absorbed by other substances, resulting in a decrease in the output power of the light source 12. According to some embodiments, an opening (not shown) is formed in the wall of the light source chamber 125, and is connected to a vacuum pump for evacuating the light source chamber 125.

The target droplet generator 121 is configured to generate a plurality of target droplets 121A in the light source chamber 125. According to some embodiments, the target droplet 121A based on tin-doped droplet (Sn droplets), in which the target droplet 121A comprises a doped tin pure tin, a tin compound (e.g. SnBr _4, SnBr _2, SnH ₄ Or a tin alloy (such as a tin-gallium alloy, a tin-indium alloy, a tin-indium-gallium alloy, or a combination of the above alloys). However, the target droplet 121A may also include other materials such as water, lithium, cesium or any material having a radiation in the extreme ultraviolet wavelength range when converted to a plasma state.

According to some embodiments, the target drop generator 121 generates a plurality of target drops 121A by means of an actuator such as a piezoelectric actuator, and arranges the target drops 121A in a straight line. An excitation region P1 (shown in FIG. 2) is incident on the light source chamber 125.

The laser source 122 is configured to generate a laser beam L that strikes one of the target droplets 121A. According to some embodiments, the laser source 122 is a carbon dioxide (CO ₂ ) laser source or other alternative type of laser source. In addition, the laser beam L generated by the laser source 122 can be incident on the target droplet 121A located in the excitation region P1 through a beam transmitting system (not shown) and a focusing member (not shown). The position of the excitation region P1 is located at the focus of the above-mentioned focusing element. According to some embodiments, the concentrating mirror 123 is provided with a window 131A that allows the laser beam L to pass and reaches the excitation region P1 (as shown in FIG. 2). When the laser source 122 strikes the target droplet 121A located in the excitation region P1, the laser source 122 can heat the target droplet 121A to a critical temperature, causing the target droplet 121A to shed electrons and generate highly ionized plasma. Further, for example, a highly ionized plasma emits extreme ultraviolet light R having a wavelength of about 13.5 nm.

The concentrating mirror 123 is configured to have a suitable coating and shape for collecting, reflecting, and focusing extreme ultraviolet light. According to some embodiments, the concentrating mirror 123 has an elliptical geometry, and the elliptical concentrating mirror 123 has a first focus in the excitation zone P1. According to some embodiments, the coating material of the collecting mirror 123 is similar to the reflective multilayer of the reticle 18. For example, the coating material of the collecting mirror 123 includes a plurality of layers (for example, a plurality of molybdenum-ruthenium film pairs) and Further included is a cover layer (eg, a layer of tantalum) coated on the plurality of layers to reflect extreme ultraviolet light. For the lithography exposure process, the concentrating mirror 123 can collect and reflect the extreme ultraviolet light R emitted by the plasma, and focus on a second focus P2 (also referred to as an intermediate focus) of the elliptical concentrating mirror 123. The ultraviolet light R is transmitted to, for example, the illumination optical system 14 of the lithography apparatus 10 and the projection optical system 20 (as shown in FIG. 1) for performing the above-described lithography exposure process.

The target droplet collector 124 is configured to collect the unused portion of the target droplet 121A described above. More specifically, the target droplet collector 124 can collect excess target droplets 121A (ie, target droplets 121A that are not excited by the laser beam L) that are not utilized to form the extreme ultraviolet light R. According to some embodiments, in the light source chamber 125, the target droplet collector 124 is disposed opposite the target droplet generator 121 to collect the unused portion of the target droplet 121A.

For the lithography exposure process, when the target material for generating the target droplet 121A in the target droplet generator 121 is about to be exhausted, it is necessary to move the target droplet generator 121 from the light source chamber 125. Removed to supplement the solid target material such as tin rods. As such, during the supplemental tin rod of the target droplet generator 121, the lithography apparatus 10 is in a shutdown state, and after the supplemental target droplet generator 12 is mounted back to the light source chamber 125, Resetting the system of lithography apparatus 10 for a period of time (e.g., re-vacuating light source chamber 125 and reheating the tin rods in target droplet generator 12 to a molten state) results in availability of lithography apparatus 10 ( Availability) and production will decrease. Further, taking the target droplet generator 121 out of the light source chamber 125 may cause the target droplet generator 121 and the target material therein to be easily contaminated by the external environment.

On the other hand, when the target droplet collector 124 collects the target droplet 121A to a certain extent (e.g., to reach the maximum collection capacity of the target droplet collector 124), then the target droplet collector 124 is required. The collected target droplets 121A are derived. This workflow also requires the lithography apparatus 10 to be shut down for a period of time, affecting its availability and throughput. In addition, the unutilized portion of the target droplet 121A directly exits the lithography apparatus 10 from the target droplet collector 124, which also causes waste of the target material.

A target material supply system provided by an embodiment of the present invention can supplement the target material without removing the target droplet generator 121 from the light source chamber 125 to save the system reset time of the lithography apparatus 10. And recovering the unused portion of the target droplet 121A collected by the target droplet collector 124 and re-supplying it to the target droplet generator 121 to generate the target droplet 121A, thereby avoiding waste of the target material. Further, the availability and yield of the lithography apparatus 10 are improved. The component configuration and function of the target material supply system 30 according to one of the embodiments will be described below with reference to FIG.

As shown in FIG. 3, the target material supply system 30 mainly includes a target droplet generator 121, a target droplet collector 124, and a target material processing device 301. The target droplet generator 121 is configured to generate a plurality of target droplets 121A in the light source chamber 125 (Fig. 2) of the lithography apparatus 10, and the target droplets 121A are available to the lithography apparatus 10 to generate poles. Ultraviolet light, while the target droplet collector 124 is configured to collect the unused portion 121B of the target droplet 121A, and the target material processing device 301 is configured to supply a molten state target material M2 to the target liquid. The drop generator 121, and the unused portion 121B of the target droplet 121A configured to recover from the target droplet collector 124 are re-supplied to the target droplet generator 121.

According to some embodiments, the target drop generator 121 includes a drop storage slot 1210 and a nozzle 1211 coupled to the drop storage slot 1210. The droplet storage tank 1210 is configured to receive and store the target material M2 from a molten state of the target material processing device 301. The nozzle 1211 is configured to generate a plurality of target droplets 121A and to direct the target droplets 121A to an excitation region P1 (shown in FIG. 2) in the light source chamber 125, thereby generating extreme ultraviolet light. According to some embodiments, a piezoelectric actuator can be coupled to the nozzle 1211 and direct the target droplets 121A to the excitation region P1 in a straight line arrangement.

Additionally, a heater 1212 can be thermally coupled to the droplet reservoir 1210 and the nozzle 1211 for heating and maintaining the target material M2 in a molten state. According to some embodiments, the heater 1212 includes a heating coil or a heated gas line and surrounds the droplet storage tank 1210 and the outer wall of the nozzle 1211. However, the heater 1212 can also be a heater of other forms (eg, an electric heating tube or a heating wire) and disposed in the droplet storage tank 1210 and/or the nozzle 1211.

According to some embodiments, the target droplet collector 124 includes a collection trough 1240 and a connecting tube 1241. The collection tank 1240 is configured to collect the unused portion 121B of the target droplet 121A produced by the target droplet generator 121 (i.e., the target droplet that is not utilized to form excessive ultraviolet light). The collection tank 1240 has a switchable opening that allows the unused portion 121B of the target droplet 121A to enter the collection tank 1240. The connecting tube 1241 (second connecting tube) is configured to fluidly couple the collecting tank 1240 and the storage tank 3010 of the target material processing device 301, and the connecting tube 1241 can be provided with a valve 1242 (for example, a solenoid valve or a pneumatic valve). To control the communication between the collection tank 1240 and the storage tank 3010. In some embodiments, the collection drop 1240 of the target drop generator 121 and the target drop collector 124 are disposed in the light source chamber 125 (FIG. 2), and the connection tube of the target drop collector 124 The 1241 and target material processing device 301 are disposed outside the light source chamber 125.

In addition, one or more heaters 1243 (second heaters) may be thermally coupled to the collection tank 1240 and the connection tube 1241 for heating and maintaining the unused portion 121B of the target droplets 121A in a molten state. According to some embodiments, the heater 1243 includes a heating coil or a heated gas line and surrounds the collecting trough 1240 and the outer wall of the connecting tube 1241. However, the heater 1243 may also be other types of heaters (eg, electric heating tubes or electric heating wires) and disposed in the collecting tank 1240 and/or the connecting tube 1241.

According to some embodiments, the storage tank 3010 and the collection tank 1240 are individually hermetically sealed chambers and have independent, active pressure controllers 3014, 1244, wherein the pressure controller 3014 (first pressure controller), 1244 (the first) The two pressure controllers respectively inflate or pump the storage tank 3010 and the collection tank 1240 (for example, nitrogen or other inert gas) to control the pressure of the tanks. For example, when the pressure controllers 3014, 1244 control the pressure of the storage tank 3010 to be less than the pressure of the collection tank 1240 (and the valve 1242 is in an open state controlled by a controller (not shown)), it is collected in the collection tank 1240. The unused portion 121B of the target droplet 121A can be transported to the storage tank 3010, thereby achieving the purpose of recovering the unused portion 121B of the target droplet 121A from the target droplet collector 124 (avoiding the target) Waste of materials). The capacity of the storage tank 3010 can be greater than or equal to the capacity of the collection tank 1240.

In addition to the function of storing the unused portion 121B of the target droplet 121A recovered from the target droplet collector 124 (hereinafter referred to simply as the recovered target droplet 121B for convenience of explanation), the target material processing device 301 The storage tank 3010 can also be used to receive one or more solid target materials M1 (eg, tin rods). According to some embodiments, an opening (not shown) is formed in the groove wall of the storage tank 3010 to allow the solid target material M1 to enter the storage tank 3010. The solid target material M1 is heated in the storage tank 3010 by the heater 3013 described below to be converted into the molten target material M2.

According to some embodiments, the target material processing device 301 also includes a connecting tube 3011 (first connecting tube) configured to fluidly couple the storage tank 3010 and the droplet storage tank 1210 of the target droplet generator 121, and the connecting tube 3011 A valve 3012 (eg, a solenoid or pneumatic valve) can be mounted to control communication between the reservoir 3010 and the droplet reservoir 1210.

In addition, one or more heaters 3013 (first heaters) may be thermally coupled to the storage tank 3010 and the connecting tube 3011 for heating and maintaining the target material M2 and/or the recovered target droplets 121B in a molten state. According to some embodiments, the heater 3013 includes a heating coil or a heated gas line and surrounds the storage tank 3010 and the outer wall of the connecting tube 3011. However, the heater 3013 may also be other forms of heaters (eg, electric heating tubes or electric heating wires) and disposed in the storage tank 3010 and/or the connecting tube 3011.

According to some embodiments, the reservoir 3010 and the droplet reservoirs 1210 of the target droplet generator 121 are individually hermetically sealed chambers and have independent, active pressure controllers 3014, 1213, wherein the pressure controller 3014, The storage tank 3010 and the droplet storage tank 1210 can be inflated or pumped (for example, nitrogen or other inert gas) to control the pressure of the chambers. For example, when the pressure controller 3014, 1213 controls the pressure of the storage tank 3010 to be greater than the pressure of the droplet storage tank 1210 (and the valve 3012 is controlled by a controller (not shown)), it is stored in the storage. The molten target material M2 and/or the recovered target droplet 121B in the tank 3010 can be transported to the droplet storage tank 1210, thereby achieving the purpose of supplementing the target droplet generator 121 with the target material. The capacity of the storage tank 3010 can be greater than or equal to the capacity of the droplet storage tank 1210.

In the above embodiment of the target material supply system 30, since the target droplet generator 121 is not required to be taken out from the light source chamber 125, the target material can be supplemented (in the molten state), thereby saving the lithography apparatus. The system reset time of 10, and avoids contamination of the target droplet generator 121 and the target material therein by the external environment. In addition, the target droplets 121B recovered from the target droplet collector 124 can be re-supplied to the target droplet generator 121 without the need to wait for the target droplet collector 124 to be fully loaded. The lithography apparatus 10 is dripped to reduce the downtime of the lithography apparatus 10, which also improves the availability and yield of the lithography apparatus 10.

With continued reference to FIG. 3, the target material supply system 30 according to some embodiments may also include one or more configurations for detecting the target material M2 and/or recycling in the storage tank 3010, the droplet storage tank 1210, and the collection tank 1240. The liquid level sensors 3015, 1214, 1215, and 1245 of the target droplets 121B (as shown in FIG. 3). Output signals of the liquid level sensors 3015, 1214, 1215, 1245 (eg, liquid level sensors of potential type, optical type or other optional form) can be transmitted to a controller (not shown), and the The controller can electrically connect and control the operation of the pressure controllers 3014, 1213, 1244.

For example, the liquid level sensor 3015 is configured to detect whether the liquid level of the target material M2 stored in the storage tank 3010 and/or the recovered target liquid droplet 121B is lower than a predetermined low liquid level. For example, 5% or 10% of the height of the storage tank 3010, and the controller can control the operation of the pressure controllers 3014 and 1244 (and the valve 1242) according to the output signal of the liquid level sensor 3015, and collect the collected in the collecting tank 1240. The unused portion 121B of the target droplet 121A is transported to the storage tank 3010, or the controller can control the pressure controller 3014 to pump the storage tank 3010 according to the output signal of the liquid level sensor 3015 (ie, After the pressure relief is completed, the user can replenish the solid target material M1 through the opening (not shown) on the storage tank 3010, and the solid target material M1 can be converted into a molten state by heating. Target material M2. In this way, the liquid level of the target material M2 stored in the storage tank 3010 and/or the recovered target droplet 121B can be maintained in a normal state, so that the target material can be stably supplied to the target droplet generator 121.

For example, the liquid level sensor 1214 is configured to detect whether the liquid level of the target material M2 stored in the liquid droplet storage tank 1210 is lower than a predetermined low liquid level, for example, the height of the liquid storage tank 1210. 5% or 10%, and the controller can control the operation of the pressure controllers 3014 and 1213 (and the valve 3012) according to the output signal of the liquid level sensor 1214, and cause the target material M2 stored in the storage tank 3010. And/or the recovered target droplets 121B are delivered to the droplet storage tank 1210. The liquid level sensor 1215 is configured to detect whether the liquid level of the target material M2 stored in the liquid droplet storage tank 1210 is higher than a predetermined high liquid level, for example, 90% or 95 of the height of the liquid storage tank 1210. %, and the controller can control the operation of the pressure controllers 3014 and 1213 (and the valve 3012) according to the output signal of the liquid level sensor 1214, so that the target material M2 and/or the recycling target stored in the storage tank 3010 The target droplet 121B is stopped from being delivered to the droplet storage tank 1210.

For example, the liquid level sensor 1245 is configured to detect whether the liquid level of the unused portion 121B of the target liquid droplet 121A collected in the collecting tank 1240 is higher than a predetermined high liquid level, such as a collecting tank. The controller 4040 or 95% of the height of the 1240, and the controller can control the operation of the pressure controllers 3014 and 1244 (and the valve 1242) according to the output signal of the liquid level sensor 1245, and the standard collected in the collecting tank 1240 The unused portion 121B of the target droplet 121A is transported to the storage tank 3010. As a result, it is possible to prevent the unused portion 121B of the target droplet 121A collected in the collecting tank 1240 from exceeding its maximum collection capacity.

According to some embodiments, the storage tank 3010 can also be divided into two hermetically sealed sub-tank chambers (each configured with a separate, active pressure controller), wherein a sub-tank chamber is coupled to the target liquid through the connecting tube 3011. The droplet generator 121 is coupled to the target droplet collector 124 through a connecting tube 1241, and a valve is disposed between the two sub-tank chambers for controlling the communication between the two sub-tank chambers. With this configuration, the target material processing device 301 can simultaneously supply the target material to the target droplet generator 121 and recover the unused portion 121B of the target droplet 121A from the target droplet collector 124, thereby improving the target. The performance of the target material supply system 30.

Continuing to refer to FIG. 3, the target material supply system 30 can also include one or more filters 3016, 1246 disposed in the flow path of the target material M2 and/or the recovered target droplet 121B for filtering. Impurities (eg, particles not used to generate extreme ultraviolet light). According to some embodiments, a filter 1246 (second filter) may be disposed in the collection tank 1240 or the connection tube 1241 of the target droplet collector 124 (as shown in FIG. 3) for filtering to be delivered to the target. The impurity in the target droplet 121B recovered by the target material processing device 301, and another filter 3016 (first filter) may be disposed in the storage tank 3010 or the connecting tube 3011 of the target material processing device 301 (eg, the third In the figure, it is used to filter the impurity to be delivered to the target material M2 of the target droplet generator 121 and/or the recovered target droplet 121B.

The filters 3016, 1246 may be sintered filters, mesh filters or other alternative filters, and are made of titanium, tungsten or glass. According to some embodiments, the filters 3016, 1246 may be of the same or different materials. In addition, the filters 3016, 1246 can be fixed to the chamber or the connecting tube of the target material processing device 301 and the target droplet collector 124 by, for example, adhesive bonding, or the filters 3016, 1246 can be combined with the target material processing device. The chambers or connecting tubes of the 301 and target droplet collectors 124 are fabricated in one piece.

The filters 3016, 1246 also include a plurality of holes or apertures for allowing non-impurity portions of the target material M2 and/or the recovered target droplets 121B to flow therethrough, and the holes are perpendicular to the target material. The M2 and/or recovered target droplets 121B flow uniformly through the plane of the general flow direction of the filters 3016, 1246. The size of the holes depends primarily on the size of the impurities to be filtered. According to some embodiments, the filters 3016, 1246 have a pore size of from about 0.1 [mu]m to about 0.5 [mu]m.

According to some embodiments, the sizes of the holes of the filters 3016, 1246 may also be different. For example, the size of the pores of the filter 3016 can be smaller than the size of the pores of the filter 1246 (as shown in Figures 4A, 4B), such that the pores of the filter 3016 can filter impurities smaller than the pores of the filter 1246. Thereby, impurities are effectively blocked from entering the target droplet generator 121. According to some embodiments, other filters may be disposed in the droplet storage tank 1210 and/or the nozzle 1211 of the target droplet generator 121 to further improve the purity of the generated target droplet 121A and the light source 12 (the first 2) The output power.

Although the target material supply system 30 of the above embodiment is used to supply the target material to the single lithography apparatus 10 (Fig. 1), the invention is not limited thereto. The target material supply system 30' according to some embodiments may also supply the target material to a plurality of lithography apparatus 10 (as shown in Fig. 5). For example, the target material supply system 30' includes a target material processing device 301 that simultaneously connects the target droplet generator 121 and the target droplet collector in each lithography apparatus 10 through a plurality of connecting tubes. 124, and can perform the above operations of supplying and recycling target materials. Although not shown, the target material processing apparatus 301 in this example may include one or more storage slots corresponding to each lithography apparatus 10.

Figure 6 is a flow diagram of a target material supply method 60 in accordance with some embodiments. In operation 61, a target material in a molten state is supplied to a target droplet generator by a target material processing device. In operation 62, a plurality of target droplets are generated by a target droplet generator, and the target droplets are utilized by an extreme ultraviolet lithography apparatus to generate extreme ultraviolet light. In operation 63, the unused portion of the target droplet is collected by a target droplet collector. In operation 64, the unused portion of the target droplets recovered from the target droplet collector is re-supplied to the target droplet generator by the target material processing device.

It is to be understood that additional operations may be provided before, during, and after the methods in the above-described embodiments, and some of the described operations may be replaced or eliminated for the methods in the different embodiments.

In summary, the target material supply system and method of the present disclosure can supply the target material to the extreme ultraviolet photolithography device in an efficient manner, and save the working time of the target droplet generator to supplement the target material. And its subsequent system reset time, as well as the ability to recover and re-supply excess target droplets to the target droplet generator, thereby increasing the availability and yield of lithography equipment.

In accordance with some embodiments, a target material supply system is provided comprising a target droplet generator, a target droplet collector, and a target material processing device. The target droplet generator is configured to generate a plurality of target droplets for use by an extreme ultraviolet lithography apparatus to generate extreme ultraviolet light. The target droplet collector is configured to collect unused portions of the target droplets described above. The target material processing apparatus is configured to supply one of the target materials in a molten state to the target droplet generator, and configured to resupply the unused portion of the target droplet recovered from the target droplet collector To the target droplet generator.

According to some embodiments, the target material processing apparatus includes a storage tank, a first connecting tube, and at least one first heater. The storage tank is configured to store the target material and the unused portion of the target droplet. The first connecting tube fluidly couples the storage tank and the target droplet generator. At least one first heater is thermally coupled to the storage tank and the first connecting tube for heating and maintaining the unused portion of the target material and the target droplet in a molten state.

According to some embodiments, the target material processing apparatus further includes a first pressure controller configured to control the pressure of the storage tank and deliver the target material and the unused portion of the target droplet to the target droplet generator .

According to some embodiments, the target material processing apparatus further includes a first filter disposed in the storage tank or the first connecting tube.

According to some embodiments, the target droplet collector includes a collection trough, a second connection tube, and at least a second heater. The trough configuration is collected to collect the unused portion of the target droplets described above. The second connecting tube fluidly couples the collecting tank and the storage tank of the target material processing device. At least one second heater is thermally coupled to the collection trough and the second connecting tube for heating and maintaining the unused portion of the target droplets in a molten state.

According to some embodiments, the target droplet collector further includes a second pressure controller configured to control the pressure of the collection tank and deliver the unused portion of the target droplet to a storage tank of the target material processing device.

According to some embodiments, the target droplet collector further includes a second filter disposed in the collection trough or the second connecting tube.

According to some embodiments, the holes of the first filter and the second filter are different in size.

According to some embodiments, an extreme ultraviolet lithography apparatus is provided, including a light source chamber, a target droplet generator, a laser light source, a concentrating mirror, a target droplet collector, and a target material. Processing device. The target droplet generator is configured to generate a plurality of target droplets in the source chamber. The laser source is configured to produce a laser beam that is used to excite the target droplets to produce extreme ultraviolet light. A concentrating mirror is disposed in the light source chamber for collecting extreme ultraviolet light. The target droplet collector is configured to collect unused portions of the target droplets described above. The target material processing device is disposed outside the light source chamber and configured to supply one of the target materials in a molten state to the target droplet generator, and configured to recover the target droplets to be recovered from the target droplet collector The unused portion is re-supplied to the target droplet generator.

According to some embodiments, a method of supplying a target material is provided, comprising supplying a target material in a molten state to a target droplet generator by a target material processing device. The above method for supplying a target material further comprises generating a plurality of target droplets by a target droplet generator, and the target droplets are used by an extreme ultraviolet lithography apparatus to generate extreme ultraviolet light. The above method of supplying a target material also includes collecting an unused portion of the target droplet by a target droplet collector. Further, the above target material supply method includes re-supplying the unused portion of the target droplet recovered from the target droplet collector to the target droplet generator by the target material processing device.

The embodiments and their advantages are described in detail above, and it is understood that various changes, substitutions and modifications may be made in the present disclosure without departing from the spirit and scope of the disclosure. Further, the scope of the present application is not intended to be limited to the specific embodiments of the process, the machine, the manufacture, the material composition, the tool, the method and the steps described in the specification. It will be readily apparent to those skilled in the art from this disclosure that, in accordance with the present disclosure, substantially the same functions or implementations as those of the corresponding embodiments described herein may be utilized. The resulting process, machine, manufacturing, material composition, tool, method or procedure. Therefore, the scope of the appended claims is intended to cover such processes, machines, manufacture, compositions of matter, tools, methods or steps. In addition, each patent application scope constitutes a separate embodiment, and combinations of different application patent scopes and embodiments are within the scope of the disclosure.

Claims (10)

 A target material supply system includes: a target droplet generator configured to generate a plurality of target droplets for use by an extreme ultraviolet lithography apparatus to generate an extreme ultraviolet light; a target droplet collector configured to collect an unused portion of the target droplets; and a target material processing device configured to supply a target material in a molten state to the target droplet And configured to re-supplied the unused portions of the target droplets recovered from the target droplet collector to the target droplet generator.    The target material supply system of claim 1, wherein the target material processing device comprises a storage tank, a first connecting tube and at least one first heater, wherein the storage tank is configured to store the standard a target material and the unused portions of the target droplets, the first connecting tube fluidly coupling the storage tank and the target droplet generator, and the at least one first heater is thermally coupled to the storage The slot and the first connecting tube are configured to heat and maintain the target material and the unused portions of the target droplets in the molten state.    The target material supply system of claim 2, wherein the target material processing device further comprises a first pressure controller configured to control the pressure of the storage tank and the target material and the standard The unused portions of the target droplets are delivered to the target droplet generator.    The target material supply system of claim 2, wherein the target material processing device further comprises a first filter disposed in the storage tank or the first connecting tube.    The target material supply system according to any one of claims 2 to 4, wherein the target droplet collector comprises a collecting tank, a second connecting tube and at least a second heater, the collecting The trough is configured to collect the unused portions of the target droplets, the second connecting tube fluidly coupling the collection trough and the storage tank of the target material processing device, and the at least one second heater Thermally coupled to the collection tank and the second connection tube for heating and maintaining the unused portions of the target droplets in the molten state.    The target material supply system of claim 5, wherein the target droplet collector further comprises a second pressure controller configured to control the pressure of the collection tank and to drop the target droplets The unused portions are delivered to the storage tank of the target material processing device.    The target material supply system of claim 5, wherein the target droplet collector further comprises a second filter disposed in the collection tank or the second connection tube.    The target material supply system of claim 7, wherein the first filter and the second filter have different hole sizes.    An extreme ultraviolet lithography apparatus comprising: a light source chamber; a target droplet generator configured to generate a plurality of target droplets in the light source chamber; a laser light source configured to generate a laser a beam of light for exciting the target droplets to generate extreme ultraviolet light; a collecting mirror disposed in the light source chamber for collecting the extreme ultraviolet light; a target droplet collector Configuring to collect unused portions of the target droplets; and a target material processing device disposed outside the light source chamber and configured to supply a target material in a molten state to the target droplets And configured to re-supplied the unused portions of the target droplets recovered from the target droplet collector to the target droplet generator.    A method for supplying a target material, comprising: supplying a target material in a molten state to a target droplet generator by a target material processing device; generating a plurality of targets by the target droplet generator a droplet, wherein the target droplets are used by an extreme ultraviolet lithography apparatus to generate extreme ultraviolet light; and an unutilized portion of the target droplets is collected by a target droplet collector; The target material processing device re-supplied the unused portions of the target droplets recovered from the target droplet collector to the target droplet generator.