Lithographic system and method of cleaning thereof

Abstract

A photolithography system and a cleaning method thereof are provided. The photolithography system includes a light source generator. The light source generator includes a mirror, a droplet generator, and a droplet catcher. The droplet generator and the droplet catcher face each other and are disposed at an area surrounding the mirror. The cleaning method includes: removing the droplet generator out of the light source generator via a load port of the light source generator; inserting a scraper assembly into the light source generator via the same load port; identifying a location of a deposit formed by droplets generated by the droplet generator using a borescope attached to the scraper assembly; removing and collecting the deposit using the scraper assembly; and withdrawing the scraper assembly with the borescope from the light source generator via the load port.

Description

[0001] Cross-references to related applications

[0002] This application claims priority to U.S. Provisional Application No. 62 / 880,046, filed July 29, 2019. The entire contents of the aforementioned patent application are hereby incorporated by reference and form part of this specification. Technical Field

[0003] Embodiments of this disclosure relate to a photolithography system and a cleaning method thereof. Background Technology

[0004] In recent years, the semiconductor industry has experienced rapid development due to the continuous increase in the integration density of various electronic components. In most cases, this increase in integration density comes from the continuous reduction in the minimum feature size of integrated circuits (ICs), which allows more smaller components to be integrated into a given area. As a result, IC manufacturing efficiency has been improved.

[0005] On the other hand, this miniaturization increases the complexity of IC manufacturing processes. For example, the need for higher-resolution lithography processes increases. In optical projection lithography systems, resolution (i.e., minimum feature size) is limited by light diffraction. According to the Rayleigh equation, the minimum feature size is proportional to the wavelength of the light source. Therefore, developing lithography systems with shorter wavelength light sources is crucial for IC miniaturization. Summary of the Invention

[0006] In one embodiment of this disclosure, a method for cleaning a photolithography system is provided. The photolithography system includes a light source generator. The light source generator includes a mirror, a droplet generator, and a droplet collector. The droplet generator and the droplet collector face each other and are disposed in a region surrounding the mirror. The method for cleaning the photolithography system includes: removing the droplet generator from the light source generator via a port; inserting a shovel assembly into the light source generator via the port; using a channel mirror attached to the shovel assembly to identify the location of deposits formed by droplets generated by the droplet generator; using the shovel assembly to remove and collect the deposits; and withdrawing the shovel assembly and the channel mirror together from the light source generator via the port.

[0007] In another embodiment of this disclosure, a photolithography system is provided. The photolithography system includes a light source generator. The light source generator includes a mirror, a droplet generator, a droplet trap, a container, and a cleaning device. The droplet generator is disposed on one side of the mirror and configured to emit droplets across the reflective side of the mirror. The droplet trap is disposed on the other side of the mirror and configured to trap at least a portion of the droplets emitted from the droplet generator. The container covers the reflective side of the mirror. Light reflected by the mirror passes through a central channel of the container. The cleaning device is attached to the mirror-facing surface of the container and adjacent to the droplet trap. The cleaning device is configured to remove deposits formed from a portion of the droplets that were not trapped by the droplet trap.

[0008] In another embodiment of this disclosure, a cleaning method for a photolithography system is provided. The photolithography system includes a light source generator. The light source generator includes a mirror, a droplet generator, a droplet trap, and a cleaning device. The droplet generator and the droplet trap face each other and are disposed in a region surrounding the mirror. The cleaning device is adjacent to the droplet trap. The cleaning method for the photolithography system includes actuating an actuator in the cleaning device to control a deposit remover in the cleaning device to remove deposits around the droplet trap. The deposits are formed from a portion of droplets generated by the droplet generator. Attached Figure Description

[0009] The various aspects of this disclosure are best understood in conjunction with the accompanying drawings and the following detailed description. It should be noted that, in accordance with industry standard practice, the various features are not drawn to scale. In fact, the dimensions of the various features may be arbitrarily increased or decreased for clarity of explanation.

[0010] Figure 1 This is a schematic diagram of a lithography system according to some embodiments of the present disclosure.

[0011] Figure 2 This is an exploded view of a light source generator according to some embodiments of the present disclosure.

[0012] Figure 3A This is a flowchart of a cleaning method for a photolithography system according to some embodiments of the present disclosure.

[0013] Figure 3B In such Figure 3A The diagram shows the insertion of the shovel assembly and pipe mirror into the main frame via one of a plurality of side loading ports during the cleaning process.

[0014] Figure 3C yes Figure 3B Enlarged view of the shovel assembly and pipe mirror shown.

[0015] Figures 4 to 6 This is a schematic diagram of a shovel assembly and a pipe mirror according to some embodiments of the present disclosure.

[0016] Figure 7 This is a schematic cross-sectional view of a built-in cleaning device in a light source generator according to some embodiments of the present disclosure. Detailed Implementation

[0017] The following disclosure provides numerous different embodiments or instances for implementing various features of the provided subject matter. Specific examples of components and arrangements are described below to simplify this disclosure. Of course, these components and arrangements are merely examples and are not intended to be limiting. For example, in the following description, forming a first feature above or on a second feature may include embodiments where the first and second features are formed in direct contact, and may also include embodiments where an additional feature may be formed between the first and second features so that the first and second features are not in direct contact. Furthermore, reference numerals and / or letters may be repeated in various instances in this disclosure. This repetition is for simplicity and clarity and does not, in itself, define a relationship between the various embodiments and / or configurations discussed.

[0018] Furthermore, for ease of description, spatial relative terms such as “below,” “under,” “lower,” “above,” and “upper” may be used herein to describe the relationship between one element or feature and another element(s) shown in the figures. In addition to the orientations depicted in the figures, the spatial relative terms are intended to cover different orientations of the device during use or operation. The device may be oriented in other ways (rotated 90 degrees or in other orientations), and the spatial relative descriptive terms used herein shall be interpreted accordingly.

[0019] It should be understood that the following embodiments of this disclosure provide applicable concepts that can be implemented in various specific contexts. The embodiments are intended to provide further explanation but are not intended to limit the scope of this disclosure.

[0020] The advanced photolithography processes, methods, and materials described in this disclosure can be used in many applications, including the fabrication of fin-type field-effect transistors (FinFETs). For example, the contents of this disclosure can be applied to patterning to form fin patterns with relatively short spacing between features. Additionally, the contents of this disclosure can also be used to form spacers for the fins of FinFETs.

[0021] Figure 1 This is a schematic diagram of a lithography system 10 according to some embodiments of the present disclosure.

[0022] refer to Figure 1In some embodiments, the lithography system 10 is an extreme ultraviolet (EUV) lithography system that uses light in the EUV wavelength range. For example, EUV wavelengths range from about 1 nanometer to about 100 nanometers. In some cases, EUV light has an emission peak at a wavelength of about 13.5 nanometers. In some embodiments, the lithography system 10 includes a light source generator 100, an exposure apparatus 200, and an excitation laser generator 300. EUV light is generated in the light source generator 100 and directed to the exposure apparatus 200. The exposure apparatus 200 (e.g., a scanner) directs the EUV light onto a photomask (not shown) to form a light pattern and projects these light patterns onto a workpiece (e.g., a semiconductor wafer) coated with a photosensitive layer (e.g., photoresist). Thus, the desired pattern is transferred from the photomask to the workpiece. In some embodiments, the light source generator 100 generates EUV light via a laser-produced plasma (LPP) mechanism. In these embodiments, the laser used to generate plasma is provided by an excitation laser generator 300. For example... Figure 1 As shown, in some embodiments, the light source generator 100 and the exposure device 200 are installed on the main floor ML of the cleanroom, while the excitation laser generator 300 is installed on the basement floor BL located below the main floor ML. Additionally, the light source generator 100 and the exposure device 200 can be placed on base plates PP1 and PP2 respectively via dampers DP1 and DP2.

[0023] In some embodiments, the light source generator 100 includes a collector 102, a droplet generator 104, and a droplet catcher 106. The collector 102, droplet generator 104, and droplet catcher 106 may be enclosed in a vacuum chamber 108. In some embodiments, an excitation laser LR generated by the excitation laser generator 300 passes through a window (e.g., an opening) of the collector 102 and impacts a droplet DR generated by the droplet generator 104, ionizing the material of the droplet DR and forming plasma in the excitation region ZE near the intersection of the excitation laser LR and the droplet DR. In some embodiments, the droplet DR is a tin (Sn) droplet. In alternative embodiments, the droplet DR may use other tin-containing materials, such as a eutectic alloy containing tin (Sn) and lithium (Li). Additionally, in some embodiments, the excitation laser LR is provided as a laser pulse (e.g., a CO2 laser pulse), and the excitation laser LR includes a pre-pulse laser and a main pulse laser. A pre-pulsed laser strikes a droplet DR, transforming it into a fine mist. A main-pulsed laser then strikes the mist, ionizing the material of the droplet DR (i.e., the mist material) to form a plasma. The plasma emits EUV light, which is reflected and focused by a mirror 102. In some embodiments, the mirror 102 is an ellipsoidal reflector. In these embodiments, the excitation region ZE may be located relatively close to one focal point of the ellipsoidal reflector, while the EUV light is focused at another focal point relatively far from the ellipsoidal reflector. The focused EUV light can serve as a light source for an exposure device 200 coupled to a light source generator 100. On the other hand, a droplet trap 106 traps excess droplets DR. In some embodiments, the droplet generator 104 and the droplet trap 106 are disposed in a region surrounding the mirror 102 and configured to face each other. Furthermore, the droplet trap 106 can be heated to a temperature above the melting point of the droplet DR material to allow excess droplets DR to be collected in liquid form. For example, the droplet DR is a tin droplet, and the droplet collector 106 can be heated to about 250°C to about 300°C (e.g., 280°C).

[0024] In some embodiments, the reflector 102 is a Bragg reflector and may be formed in an elliptical shape having a concave side (i.e., a reflecting side) and a convex side (i.e., a rear side). In these embodiments, although not shown, the reflector 102 includes a stack of reflective layers coated on a concave surface of a substrate. The stack of reflective layers includes multiple pairs of reflective layers, each having a first reflective layer (e.g., a Mo layer) and a second reflective layer (e.g., a Si layer or a Be layer). The first and second reflective layers are alternately formed over the substrate. For example, the stack of reflective layers may include 50 or more pairs of reflective layers. In some embodiments, the Bragg reflector further includes a top cap layer (not shown), such as a Ru layer, formed over the stack of reflective layers. Additionally, in some embodiments, the reflector 102 further includes a grating structure (not shown). The grating structure (e.g., a silicon nitride grating pattern) is formed over the Bragg reflector. During the process used to generate EUV light, ions or atoms of the droplet DR can be deposited or bombarded onto mirror 102 and other portions of the vacuum chamber 108. This can reduce the reflectivity of mirror 102 and decrease the intensity of the reflected EUV light. One or more mechanisms can be employed to reduce undesirable deposition or bombardment on mirror 102. In some embodiments, a buffer gas is provided to the reflective side of mirror 102 (e.g., the concave side of mirror 102). The buffer gas can react with atoms of the droplet DR to be deposited on mirror 102, forming a gaseous product that can be extracted from the vacuum chamber 108. For example, when the droplet DR is a tin droplet, the buffer gas can contain hydrogen, and the hydrogen-containing buffer gas can react with the tin droplet to form a gaseous product of tin hydride (SnH4). In some embodiments, the buffer gas is provided by gas supply devices 110 and 112. A gas supply device 110 is disposed on the rear side of the reflector 102, and the supplied buffer gas can pass through the reflector 102 to the reflective side of the reflector 102. For example, the buffer gas supplied by the gas supply device 110 and the excitation laser LR can pass through the same window (e.g., opening) located in the central region of the reflector 102. On the other hand, a gas supply device 112 is disposed on the reflective side of the reflector 102 and can supply buffer gas to the vicinity of the excitation region ZE to prevent atoms of the droplet DR from depositing in the vacuum chamber 108 on the reflector 102 and other components located on the reflective side of the reflector 102. In some embodiments, the light source generator 100 further includes at least one magnetic coil (not shown) disposed in a region surrounding the reflector 102. The magnetic coil is configured to generate a magnetic field near the excitation region ZE. The magnetic field can confine ions of the droplet DR emitted from the plasma to prevent these ions from impacting the reflector 102 and other components located on the reflective side of the reflector 102 in the vacuum chamber 108.

[0025] In some embodiments, the light source generator 100 further includes a debris collection mechanism 114. The debris collection mechanism 114 has a central channel extending through the light source generator 100 along its extension direction and includes a plurality of blades (not shown) that operate at an angle around the central channel. Reflected EUV light passes through the central channel of the debris collection mechanism and then exits the light source generator 100. The blades are configured to discharge debris, such as atoms of the droplet DR (e.g., tin atoms), gaseous products of the droplet DR, and buffer gases or combinations thereof, from the central channel. The blades can be heated so that debris adheres firmly to the surface of the blades and melts to form droplets that travel along and between the blades for collection. In some embodiments, the width of the central channel may decrease in a direction away from the reflector 102, and the debris collection mechanism 114 may have a frustoconical shape.

[0026] After exiting the light source generator 100, the reflected and focused EUV light enters the exposure apparatus 200. In some embodiments, although not shown, the exposure apparatus 200 includes multiple reflective optical components, a photomask holding mechanism, and a workpiece holding mechanism. The EUV light from the light source generator 100 is guided by some of the reflective optical components onto a photomask, which is secured to the photomask holding mechanism (e.g., a vacuum chuck or an electrostatic chuck). In some embodiments, the photomask is a reflective photomask, and the EUV light is partially reflected by the reflective photomask to form an EUV light pattern. Subsequently, these EUV light patterns are projected onto a workpiece (e.g., a semiconductor wafer) held by the workpiece holding mechanism (e.g., a vacuum chuck or an electrostatic chuck) via other reflective optical components. The workpiece is coated with a photosensitive material. After being exposed to the projected EUV light pattern and undergoing a development process, the photosensitive material is patterned. The pattern of the photosensitive material can be transferred to the workpiece when performing an etching process by using the photosensitive material as a mask. In some embodiments, the reflective photomask includes a Bragg reflector and an absorption pattern formed above the Bragg reflector. The reflective layer stack may include multiple pairs of reflective layers, each comprising a first reflective layer (e.g., a Mo layer) and a second reflective layer (e.g., a Si layer or a Be layer). The first and second reflective layers are formed alternately above the substrate. For example, the Bragg reflector includes 50 or more pairs of reflective layers. In some embodiments, the Bragg reflector further includes a capping layer (e.g., a Ru layer) covering the reflective layer stack to protect it. Absorption patterns, such as tantalum boron nitride (TaBN) patterns or tantalum nitride (TaN) patterns, define an EUV light pattern projected onto the workpiece. Some portions of the incident EUV light are absorbed by the absorption pattern, while other portions are reflected by the Bragg reflector to form the light pattern. In embodiments where the Bragg reflector includes a capping layer, the absorption pattern is formed above the capping layer.

[0027] In some embodiments, an excitation laser generator 300 configured to generate an excitation laser LR includes a laser generation system 310, a laser guiding optics 320, and a focusing device 330. Laser pulses (including a main pulse laser and a pre-pulse laser) are generated by the laser generation system 310 and delivered and focused via the laser guiding optics 320 and the focusing device 330, respectively. In some embodiments, the laser generation system 310 includes one or more laser source discharge devices and / or lamps (neither shown) for providing laser pulses via direct current (DC) excitation or radio frequency (RF) excitation. For example, the laser source may be carbon dioxide (CO2) or neodymium-doped yttrium aluminum garnet (Nd:YAG), and the wavelength of the generated laser pulses may be in the range of about 9100 nm to about 11000 nm (e.g., about 10600 nm). Additionally, the laser generation system 310 may have one or more power amplifiers for increasing output power. The generated laser pulses are guided, shaped, and focused by laser guiding optics 320 and focusing device 330, forming an excitation laser LR for generating plasma by impacting droplets DR in the light source generator 100.

[0028] Figure 2 This is an exploded view of a light source generator 100 according to some embodiments of the present disclosure.

[0029] refer to Figure 1 and Figure 2 In some embodiments, the reflector 102, the droplet generator 104, and the droplet collector 106 are mounted in the main frame MF. The main frame MF can be considered as... Figure 1 This is a portion of the vacuum chamber 108 shown. Additionally, the vacuum chamber 108 may further include a vessel VS, a lower cone LC, and an upper cone UC. The vessel VS is connected to the main frame MF and surrounds an opening in the main frame MF, located on the reflecting side (e.g., the concave side) of the reflector 102. The vessel VS surrounds... Figure 1 The debris collection mechanism 114 is shown. The lower cone LC and the upper cone UC are collectively referred to as the emission cones, which connect the container VS to the intermediate focus where EUV light reflected by mirror 102 is focused. The EUV light reflected by mirror 102 passes sequentially through the main frame MF, container VS, lower cone LC, and upper cone UC, and is then focused at the intermediate focus outside the upper cone UC. Subsequently, the EUV light enters... Figure 1 The exposure apparatus 200 is shown. In some embodiments, the vacuum chamber 108 further includes an upper measuring frame UF and a bottom cover BC. The measuring frame UF covers the sidewalls of the container VS. Water and / or gas pipes can extend into the vacuum chamber 108 through the measuring frame UF, and pressure gauges and / or temperature sensors can be mounted on the measuring frame UF. The bottom cover BC covers the bottom side of the main frame MF and is located on the rear side (e.g., the convex side) of the reflector 102. Figure 1 The excitation laser LR shown can pass through the window of the bottom cover BC and the window of the reflector 102, and then reach the reflecting side (e.g., the concave side) of the reflector 102.

[0030] refer to Figure 2 In some embodiments, the main frame MF has a main loading port MP and two side loading ports SP. The main loading port MP is located between the side loading ports SP. The reflector 102 can be mounted into or removed from the main frame MF via the main loading port MP. In some embodiments, the vacuum gate VD is configured to seal the main loading port MP. Additionally, the lower measurement frame LF can be fastened to the vacuum gate VD from, for example, outside the main frame MF. One or more detection devices can be mounted on the lower measurement frame LF and can extend into the main frame MF through the vacuum gate VD. For example, the detection device may include a camera (e.g., including a fine droplet steering camera (FDSC), a coarse droplet steering camera (CDSC), a droplet formation camera (DFC), etc., or combinations thereof), a backlight laser module (BLM), a droplet illumination module (DIM), a droplet detection module (DDM), etc., or combinations thereof. On the other hand, the droplet generator 104 and the droplet collector 106 can be inserted into the main frame MF via two side loading ports SP, respectively. During the process used to generate EUV light, some droplets DR (such as...) Figure 1 As shown, droplets (DR) may accidentally deposit on the portion of vacuum chamber 108 surrounding droplet collector 106 after passing through the excitation region ZE, instead of being collected by droplet collector 106. Subsequently emitted droplets (DR) may impact the deposit and bounce off mirror 102. Therefore, the reflectivity of mirror 102 is impaired, and a method for cleaning the deposit is required.

[0031] Figure 3A This is a process flow diagram of a cleaning method for a light source generator 100 according to some embodiments of the present disclosure. Figure 3B In such Figure 3A The diagram shows the insertion of the shovel assembly 400 and the pipe mirror 500 into the main frame MF via one of a plurality of side loading ports SP during the cleaning process. Figure 3C yes Figure 3B An enlarged view of the shovel assembly 400 and the pipe mirror 500 shown. A cleaning method for the light source generator 100 includes the following steps.

[0032] refer to Figure 2 , Figure 3A as well as Figure 3B Step S100 is executed to remove the droplet generator 104 from the main frame MF via one of a plurality of side loading ports SP. The droplet generator 104 can be removed from the main frame MF when the pressure inside the main frame MF is balanced with the pressure outside the main frame MF. After the droplet generator 104 is removed from the main frame MF, the reflector 102 and the droplet trap 106 can remain in the main frame MF. In addition, after the droplet generator 104 is removed from the main frame MF, the cavity in the main frame MF can be connected to the outside via the side loading port SP through which the droplet generator 104 is removed.

[0033] refer to Figure 3A , Figure 3B Step S102 is performed to insert the shovel assembly 400 and the pipe mirror 500 into the main frame MF via the side loading port SP for removing the droplet generator 104. The shovel assembly 400 is configured to knock out and collect sediment. The pipe mirror 500 is attached to the shovel assembly 400 and configured to identify sediment in the main frame MF and / or the container VS (e.g., Figure 2 The location of the sediment (as shown in the diagram) is monitored, and the removal of sediment performed using the shovel assembly 400 is monitored. Generally, the sediment is located in the container VS (as shown in the diagram) connected from above to the main frame MF. Figure 2 The deposits are located around the inlet (shown in the diagram) and adjacent to the droplet trap 106. For example, the deposits may be located on the bottom surface of the container VS adjacent to the droplet trap 106, and / or on the top portion of the main frame MF adjacent to the droplet trap 106. However, deposits at other locations may also be removed using the shovel assembly 400 and the pipe mirror 500; this disclosure is not limited to removing deposits at specific locations. In some embodiments, the shovel assembly 400 and the pipe mirror 500 are manually inserted into the main frame MF. In alternative embodiments, the shovel assembly 400 and the pipe mirror 500 attached to the shovel assembly 400 are manipulated by a robotic arm (not shown). In these alternative embodiments, the shovel assembly 400 and the pipe mirror 500 are inserted into the main frame MF by a robotic arm.

[0034] refer to Figure 3B and Figure 3CIn some embodiments, the shovel assembly 400 includes a control lever 402 and a shovel 404 connected to the control lever 402. The control lever 402 is configured to be operated manually or by a robotic arm. The distal end of the control lever 402 is connected to the shovel 404, while the proximal end of the control lever 402 is held by an operator or the robotic arm. In some embodiments, the control lever 402 is telescopic and can be extended or shortened depending on the location of the deposit, which can be identified by the pipe mirror 500. The shovel 404 is configured to strike the deposit to knock it away and carries a load no longer attached to the main frame MF and / or container VS (e.g., Figure 2 The shovel 404 is a deposit (shown in the diagram). In some embodiments, the shovel 404 is made of a rigid material such as metal (e.g., steel). Additionally, in some embodiments, the shovel 404 is coated with an adhesive layer (not shown). This adhesive layer, such as a colloidal layer, is configured to adhere deposits knocked off from the main frame MF and / or container VS. In these embodiments, the removed deposits are better collected on the shovel 404 after the cleaning process is complete, thus preventing these deposits from remaining in the light source generator 100 and causing contamination. Regarding the dimensions of the shovel assembly 400, the width W of the shovel 404... 404 The width W of the side loading port SP into which the shovel assembly 400 is inserted is smaller than the width of the shovel assembly 400. SP Additionally, the shovel assembly 400 will be long enough to reach the side loading port SP through which the droplet trap 106 is inserted, so that deposits around the droplet trap 106 can be removed by the shovel assembly 400. For example, the width W 404 It can be within the range of 5 cm to 10 cm (e.g., 6 cm), while the total length L of the shovel assembly is 400. 400 It can be in the range of 125 cm to 215 cm.

[0035] The pipe mirror 500 attached to the control lever 402 may include a detection device 502, a display device 504, and a wire 506 connecting the detection device 502 and the display device 504. The detection device 502 and the wire 506 are attached to the shovel assembly 400 (e.g., the control lever 402 of the shovel assembly 400) via, for example, one or more adhesive tapes TP, and move together with the shovel assembly 400. In some embodiments, the detection device 502 is fixed near the distal end of the control lever 402 (i.e., near where the shovel 404 is attached). Alternatively, the display device 504 may remain outside the main frame MF even when the shovel assembly 400, the detection device 502, and a portion of the wire 506 are inserted into the main frame MF. The detection device 502, such as that of a camera, is configured to capture still or video images from inside the main frame MF and / or the container VS, and the wire 506 (e.g., an optical fiber) is configured to transmit the images captured by the detection device 502 to the display device 504. The display device 504, remaining outside the main frame MF, is configured to display these captured images. Based on the image displayed on the display device 504, the location of the deposit can be identified, and the removal of the deposit can be monitored. In some embodiments, the detection device 502 is equipped with an illumination device (not shown) configured to illuminate the target observed by the detection device 502.

[0036] refer to Figure 3A and Figure 3B Execute step S104 to operate the shovel assembly 400 to knock off the main frame MF and / or container VS (e.g. Figure 2 The sediment is shown in the diagram. During sediment removal, the shovel 404 of the shovel assembly 400 is operated to remove sediment from the main frame MF and / or container VS (as shown in the diagram). Figure 2 The shovel assembly 400 is knocked out (as shown in the diagram) and the removed sediment is collected. In some embodiments, the shovel 500 can monitor the removal process, and the operator can adjust the movement of the shovel assembly 400 based on the images provided by the shovel 500.

[0037] Subsequently, step S106 is performed to remove the shovel assembly 400, which carries the removed sediment, from the main frame MF via the same side loading port SP through which it is inserted. Simultaneously, the pipe mirror 500 attached to the shovel assembly 400 is also removed from the main frame MF. The sediment carried by the shovel assembly 400 is then removed from the shovel assembly 400. This completes the process for removing sediment from the main frame MF and / or the container VS (e.g., ...). Figure 2 A single cleaning cycle is performed on the sediment in the sample (as shown in the diagram). The cleaning cycle includes steps S102, S104, and S106. In some embodiments, more than one cleaning cycle may be performed to further clean the main frame MF and / or the container VS. Furthermore, after performing one or more cleaning cycles, the droplet generator 104 (as shown in the diagram) is loaded via the same side loading port SP used for inserting and removing the shovel assembly 400. Figure 2 (As shown in the image) Install it back into the main frame MF.

[0038] Based on the above, a cleaning method for removing undesirable deposits from a light source generator 100 according to some embodiments of this disclosure includes: removing a droplet generator 104 from the main frame MF of the light source generator 100 via one of a plurality of side loading ports SP of the main frame MF; inserting a shovel assembly 400 into the main frame MF via the same side loading port SP; using the shovel assembly 400 to knock off and collect the deposits; and removing the shovel assembly 400 from the main frame MF. In this manner, cleaning can be performed without removing the reflector 102 from the main frame MF via the main loading port MP. Due to the complex components installed around the main loading port MP, removing the reflector 102 from the main frame MF via the main loading port MP and moving the reflector 102 into the main frame MF is extremely time-consuming. For example, removing the reflector 102 from the main frame MF via the main loading port MP and moving the reflector 102 into the main frame MF can take at least three working days. Therefore, since removing the reflector 102 via the main loading port MP is avoided, the time required to perform the cleaning method according to some embodiments of the present disclosure can be significantly reduced. For example, the cleaning method according to some embodiments of the present disclosure can be completed in less than 12 hours. Furthermore, in some embodiments, the cleaning method according to some embodiments of the present disclosure is aided by using a pipe mirror 500 to identify the location of deposits and monitor the deposit removal process.

[0039] Figure 4 This is a schematic diagram of a shovel assembly 400a and a pipe mirror 500 according to some embodiments of the present disclosure. Figure 4 The shovel assembly 400a shown is similar to... Figure 3C The shovel assembly 400 shown is illustrated. The differences between them will be discussed, and identical or similar parts will not be repeated.

[0040] refer to Figure 3C and Figure 4 ,like Figure 4 The shovel assembly 400a shown is similar to... Figure 3C The differences between the shovel assemblies 400 shown are as follows: Figure 4The shovel assembly 400a shown further includes a suction pipe 406 and a pump 408. At least a portion of the suction pipe 406 is attached to a control rod 402 and configured to move together with the control rod 402, the shovel 404, and a portion of the pipe mirror 500. On the other hand, the pump 408 can remain outside the main frame MF even when the suction pipe 406 is inserted into the main frame MF. The proximal end of the suction pipe 406 is connected to the pump 408, while the distal end of the suction pipe 406 reaches the shovel 404. The pump 408 is configured to extract the removed sediment through the suction pipe 406. In this way, the removed sediment can be pumped out of the main frame MF immediately during the cleaning process. Therefore, the possibility of leaving the removed sediment in the main frame MF and / or the container VS can be further reduced.

[0041] Figure 5 This is a schematic diagram of a shovel assembly 400b and a pipe mirror 500 according to some embodiments of the present disclosure. Figure 5 The shovel assembly 400b shown is similar to... Figure 3C The shovel assembly 400 shown is illustrated. The differences between them will be discussed, and identical or similar parts will not be repeated.

[0042] refer to Figure 3C and Figure 5 ,like Figure 5 The shovel assembly 400b shown is as follows Figure 3C The difference between the shovel assemblies 400 shown is that, as Figure 5 The shovel assembly 400b shown further includes a heating device 410, a power supply 412, and a wire 414 connecting the heating device 410 and the power supply 412. At least a portion of the heating device 410 and the wire 414 are attached to a control lever 402 and configured to move together with the control lever 402, the shovel 404, and a portion of the pipe mirror 500. On the other hand, even when a portion of the heating device 410 and the wire 414 are inserted into the main frame MF, the power supply 412 can remain outside the main frame MF. The heating device 410, like a heating gun, is configured to melt or soften deposits, while the power supply 412 is configured to supply power (e.g., electrical power) to the heating device 410 via the wire 414. Because the deposits are melted or softened, they are more easily removed from the main frame MF and / or the container VS (e.g., Figure 2 (As shown in the diagram) Removes deposits. In some embodiments, the heating device 410 is attached to the control rod 402 near the distal end of the control rod 402 to which the shovel 404 is connected. In these embodiments, the heating device 410 can be closer to the heating target (i.e., the deposits) and can improve heating efficiency.

[0043] Figure 6 This is a schematic diagram of a shovel assembly 400c and a pipe mirror 500 according to some embodiments of the present disclosure. Figure 6The shovel assembly 400c shown is similar to... Figure 3C The shovel assembly 400 shown is illustrated. The differences between them will be discussed, and identical or similar parts will not be repeated.

[0044] refer to Figure 3C and Figure 6 ,like Figure 6 The shovel assembly 400c shown is similar to... Figure 3C The differences between the shovel assemblies 400 shown are as follows: Figure 6 The shovel assembly 400c shown further includes a resilient cover layer 416. The resilient cover layer 416 covers the edge portion of the shovel 404 to prevent the shovel 404 from damaging the main frame MF and / or container VS (such as...) during sediment removal. Figure 2 (as shown in the diagram). In some embodiments, the elastic cover 416 may be a lint-free cloth or lint-free tape.

[0045] Figure 7 A light source generator 100 according to some embodiments of this disclosure (e.g.) Figure 2 A schematic cross-sectional view of the built-in cleaning device 600 shown in the diagram. It should be noted that... Figure 7 Only a portion of the light source generator 100 near the entrance of the container VS is schematically depicted, while other components of the light source generator 100 are omitted.

[0046] refer to Figure 2 and Figure 7 In some embodiments, the light source generator 100 further includes a built-in cleaning device 600. The built-in cleaning device 600 is configured to remove undesirable deposits as described above (e.g., [missing information]) without removing any of the reflector 102, droplet generator 104, and droplet trap 106 from the main frame MF. Figure 7The image shows deposits (DP). In other words, the built-in cleaning device 600 can be considered as an in-line type cleaning apparatus that can operate without disrupting the vacuum conditions of the light source generator 100. The built-in cleaning device 600 is located near areas where undesirable deposits (e.g., deposits DP) are likely to occur. In some embodiments, a detection device (not shown) inserted into the main frame MF is configured to monitor the formation of deposits (e.g., deposits DP). In these embodiments, the location of the built-in cleaning device 600 can be determined based on images captured by the detection device. For example, the detection device may include a camera, which can be inserted into the main frame MF through a main loading port MP covered by a vacuum door VD and a lower measurement frame LF. In an alternative embodiment, the location of the built-in cleaning device 600 can be determined by observing the location of deposits (e.g., deposits DP) during maintenance of the light source generator 100. During maintenance of the light source generator 100, the lower measurement frame LF and vacuum door VD can be detached from the main frame MF, and the reflector 102 can be removed from the main frame MF via the main loading port MP. Therefore, the main frame MF and / or the container VS can be observed (e.g., via the main loading port MP), and locations where sediments (e.g., sediment DP) are likely to form can be determined. For example, such as... Figure 7 The illustration exemplifies how deposits (DP) tend to form near the droplet trap 106 on the bottom surface of the container VS. Correspondingly, a built-in cleaning device 600 can be attached to the bottom surface of the container VS and is located adjacent to the droplet trap 106.

[0047] refer to Figure 7 In some embodiments, the built-in cleaning device 600 includes a deposit remover 602 and an actuator 604. The actuator 604 is attached, for example, to the bottom surface of the container VS and is laterally connected to the deposit remover 602. The actuator 604 is configured to control the movement of the deposit remover 602 for knocking out deposits DP. In other words, the deposit remover 602 is connected to, for example, a... Figure 3B The shovel assembly 400 shown has a similar function, except that the sediment remover 602 is fixed inside the main frame MF, while... Figure 3B The shovel assembly 400 shown is only inserted into the main frame MF when a cleaning process is required. Furthermore, the actuator 604 functions similarly to an operator or reference. Figure 3B The described robotic arm is because both the actuator 604 and the operator / robotic arm are provided for pushing another component (i.e., such as...). Figure 3B The shovel assembly 400 shown and as Figure 7 The sediment remover 602 shown uses force to knock away sediment. Regarding the size of the built-in cleaning device 600, the built-in cleaning device 600 may have a larger... Figure 3B The shovel assembly 400 shown is much smaller in size, and the built-in cleaning device 600 is comparable in size to the diameter D of the droplet trap 106. 106 Quite. For example, the total length L of a 600-meter built-in cleaning device. 600 The diameter D of the droplet trap 106 106 The ratio can be in the range of 1 to 2, and the diameter D 106 The range is from 5 cm to 10 cm. In some embodiments, the actuator 604 is a pneumatic actuator and is configured to push forward and pull back the deposit remover 602 so that the deposit DP can be impacted and knocked away by the deposit remover 602. In some embodiments, the deposit remover 602 includes an impact portion 602a, a collection trough 602b, and a connecting portion 602c connecting the impact portion 602a and the collection trough 602b. The impact portion 602a is configured to impact the deposit DP. In some embodiments, the impact portion 602a extends along the push / pull direction of the actuator 604 and may have a rod-like shape. Additionally, the impact portion 602a may have a tip (not shown) facing the deposit DP, which may help knock away the deposit DP. The collection trough 602b is disposed below the impact portion 602a and configured to collect the deposit DP knocked away by the impact portion 602a. In some embodiments, the collected deposits may be removed during maintenance of the light source generator 100. Furthermore, in some embodiments, the connecting portion 602c between the impact portion 602a and the collection groove 602b extends vertically and can indirectly contact the actuator 604.

[0048] although Figure 7 Only a single built-in cleaning device 600 is depicted in this disclosure, but those skilled in the art can place more than one built-in cleaning device 600 depending on the location of the deposits. This disclosure is not limited to a certain number of built-in cleaning devices 600.

[0049] As described above, a cleaning method for a lithography system according to some embodiments of the present disclosure includes removing undesirable deposits in a light source generator without removing a mirror from the light source generator. Since the removal and insertion of the mirror is avoided, the time required to perform the cleaning method can be significantly reduced, and the efficiency of the cleaning method can be greatly improved. In some embodiments, the cleaning method is implemented by inserting a shovel assembly into the main frame of the light source generator via one of a plurality of side loading ports, and removing the deposits using the shovel assembly. In an alternative embodiment, the cleaning method is implemented by driving a built-in cleaning device disposed in the light source generator to remove the deposits.

[0050] In one embodiment of this disclosure, a method for cleaning a photolithography system is provided. The photolithography system includes a light source generator. The light source generator includes a mirror, a droplet generator, and a droplet collector. The droplet generator and the droplet collector face each other and are disposed in a region surrounding the mirror. The method for cleaning the photolithography system includes: removing the droplet generator from the light source generator via a port; inserting a shovel assembly into the light source generator via the port; using a channel mirror attached to the shovel assembly to identify the location of deposits formed by droplets generated by the droplet generator; using the shovel assembly to remove and collect the deposits; and withdrawing the shovel assembly and the channel mirror together from the light source generator via the port.

[0051] In some embodiments, the steps of removing the droplet generator, inserting the shovel assembly, identifying the location of the deposit, removing the deposit, and withdrawing the shovel assembly are performed without removing the reflector from the light source generator.

[0052] In some embodiments, the shovel assembly is operated manually.

[0053] In some embodiments, the shovel assembly is operated by a robotic arm.

[0054] In some embodiments, the shovel assembly includes a control lever and a shovel connected to the control lever, the shovel being configured to contact the deposit.

[0055] In some embodiments, the spatula is coated with an adhesive material.

[0056] In some embodiments, the edge portion of the shovel is covered by an elastic covering layer.

[0057] In some embodiments, the shovel assembly further includes a suction pipe and a pump, the suction pipe being attached to the control lever, and the pump being configured to extract the removed sediment through the suction pipe.

[0058] In some embodiments, the shovel assembly further includes a heating device attached to the control lever and configured to melt or soften the deposit to be removed.

[0059] In some embodiments, the cleaning method for the lithography system further includes: monitoring the removal of the deposits by using the channel mirror; and adjusting the movement of the shovel assembly based on an image presented by the channel mirror during the removal of the deposits.

[0060] In some embodiments, the light source generator also has two additional loading ports through which the reflector and the droplet trap are respectively mounted and removed.

[0061] In another embodiment of this disclosure, a photolithography system is provided. The photolithography system includes a light source generator. The light source generator includes a mirror, a droplet generator, a droplet trap, a container, and a cleaning device. The droplet generator is disposed on one side of the mirror and configured to emit droplets across the reflective side of the mirror. The droplet trap is disposed on the other side of the mirror and configured to trap at least a portion of the droplets emitted from the droplet generator. The container covers the reflective side of the mirror. Light reflected by the mirror passes through a central channel of the container. The cleaning device is attached to the mirror-facing surface of the container and adjacent to the droplet trap. The cleaning device is configured to remove deposits formed from a portion of the droplets that were not trapped by the droplet trap.

[0062] In some embodiments, the cleaning device is configured to remove the deposit without removing any of the reflector, the droplet generator, and the droplet trap from the light source generator.

[0063] In some embodiments, the cleaning device includes a deposit remover and an actuator attached to the surface of the container and configured to control movement of the deposit remover for knocking out the deposits.

[0064] In some embodiments, the sediment remover has an impact portion, a collection tank, and a connection portion connecting the impact portion and the collection tank, the impact portion contacting the actuator and extending in the pushing direction of the actuator, and the collection tank located below the impact portion and configured to collect the removed sediment.

[0065] In some embodiments, the actuator is a pneumatic actuator.

[0066] In some embodiments, the light source generator further includes a main frame in which the reflector, the droplet generator, and the droplet trap are located, and the main frame has openings around which the container is attached.

[0067] In another embodiment of this disclosure, a cleaning method for a photolithography system is provided. The photolithography system includes a light source generator. The light source generator includes a mirror, a droplet generator, a droplet trap, and a cleaning device. The droplet generator and the droplet trap face each other and are disposed in a region surrounding the mirror. The cleaning device is adjacent to the droplet trap. The cleaning method for the photolithography system includes actuating an actuator in the cleaning device to control a deposit remover in the cleaning device to remove deposits around the droplet trap. The deposits are formed from a portion of droplets generated by the droplet generator.

[0068] In some embodiments, the removal of the deposit is performed without removing any of the reflector, the droplet generator, and the droplet trap from the light source generator.

[0069] In some embodiments, the sediment remover has an impact portion, a collection tank, and a connection portion connecting the impact portion and the collection tank, the impact portion contacting the actuator and extending in the pushing direction of the actuator, and the collection tank located below the impact portion and configured to collect the removed sediment.

[0070] The foregoing outlines features of several embodiments to enable those skilled in the art to better understand various aspects of this disclosure. Those skilled in the art will understand that this disclosure can be readily used as a basis for designing or modifying other processes and structures to achieve the same purposes and / or obtain the same advantages of the embodiments introduced herein. Those skilled in the art will also recognize that such equivalent constructions do not depart from the spirit and scope of this disclosure, and that various changes, substitutions, and modifications can be made herein without departing from the spirit and scope of this disclosure.

Claims

1. A cleaning method for a photolithography system, wherein the photolithography system includes a light source generator, the light source generator including a mirror, a droplet generator, and a droplet trap, the droplet generator and the droplet trap facing each other and disposed in a region surrounding the mirror, and the cleaning method for the photolithography system includes: The droplet generator is removed from the light source generator via the loading port of the light source generator; The shovel assembly is inserted into the light source generator via the loading port; The location of deposits formed by droplets generated by the droplet generator is identified using a pipe mirror attached to the shovel assembly, wherein the shovel assembly includes a control lever, a shovel connected to the control lever, and a heating device attached to the control lever; Move the control lever, the shovel, and the heating device to bring the heating device close to the deposit, and melt or soften the deposit to be removed by the heating device; The shovel assembly is used to remove and collect the sediment when it has been melted or softened, and the shovel is configured to contact the sediment. as well as The shovel assembly, together with the pipe mirror, is removed from the light source generator via the loading port.

2. The cleaning method for a photolithography system according to claim 1, wherein the steps of removing the droplet generator, inserting the shovel assembly, identifying the location of the deposit, removing the deposit, and withdrawing the shovel assembly are performed without removing the mirror from the light source generator.

3. The cleaning method for the photolithography system according to claim 1, wherein the shovel assembly is operated manually.

4. The cleaning method for the photolithography system according to claim 1, wherein the shovel assembly is operated by a robotic arm.

5. The cleaning method for the photolithography system according to claim 1, wherein the spatula is coated with an adhesive material.

6. The cleaning method for the photolithography system according to claim 1, wherein the edge portion of the shovel is covered by an elastic coating layer.

7. The cleaning method for a lithography system according to claim 1, wherein the shovel assembly further includes a suction tube and a pump, the suction tube being attached to the control lever, and the pump being configured to extract the removed deposits through the suction tube.

8. The cleaning method for the photolithography system according to claim 1, further comprising: The removal of the deposits is monitored by using the pipe mirror; as well as The movement of the shovel assembly is adjusted based on the image presented by the pipe mirror during the removal of the sediment.

9. The cleaning method for a photolithography system according to claim 1, wherein the light source generator further comprises two additional loading ports, through which the reflector and the droplet trap are respectively mounted and removed.

10. A cleaning method for a photolithography system, comprising: The droplet generator is removed from the light source generator via a side port in the lithography system, such that the droplet trap of the light source generator facing the side port is accessible through the side port. The shovel assembly and the pipe mirror are inserted into the cavity of the light source generator via the side port, wherein the pipe mirror is attached to the shovel assembly, and the shovel assembly includes a heating device, a control lever, and a shovel, wherein the control lever is connected to the shovel, and the heating device is configured to move together with the control lever, the shovel, and a portion of the pipe mirror; The pipe mirror is used to identify the location of droplet deposits generated by the droplet generator and located near the droplet collector, wherein the shovel assembly controls the movement of the pipe mirror; The heating device is moved close to the droplet deposit, and the heating device melts or softens the droplet deposit. The droplet deposits are removed and collected by moving the shovel assembly; as well as The shovel assembly and the pipe mirror are removed from the cavity via the side port.

11. The cleaning method for the photolithography system according to claim 10, wherein the photolithography system is an extreme ultraviolet photolithography system.

12. The cleaning method for the photolithography system according to claim 10, wherein the material of the droplet deposit comprises tin.

13. The cleaning method for a lithography system according to claim 10, wherein the shovel assembly knocks off and carries the droplet deposits.

14. The cleaning method for a photolithography system according to claim 10, wherein the shovel assembly knocks off the droplet deposit and extracts the droplet deposit from the cavity.

15. The cleaning method for a lithography system according to claim 10, wherein the light source generator further comprises an ellipsoidal reflector located between the side port and the droplet trap, and the ellipsoidal reflector remains within the cavity during cleaning of the lithography system.

16. A cleaning method for a photolithography system, comprising: With the main port of the light source generator of the lithography system kept closed, the droplet generator is removed from the light source generator through the side port of the light source generator, wherein the size of the main port is larger than the size of the side port. With the main port still closed, the shovel assembly is inserted into the cavity of the light source generator through the side port, wherein the shovel assembly includes a heating device, a control lever, and a shovel, wherein the control lever is connected to the shovel, and the heating device is configured to move together with the control lever and the shovel; The heating device is moved to bring it close to the droplet deposits located around the droplet trap of the light source generator, and the heating device melts or softens the droplet deposits. as well as The droplet deposits are removed and collected by moving the shovel assembly.

17. The cleaning method for a lithography system according to claim 16, wherein the channel mirror is inserted into the cavity along with the spatula assembly and is configured to acquire an internal image of the cavity.

Images