Chamber cleaning for dry development of metal organic photoresists.

Abstract

Embodiments disclosed herein include a method of cleaning a chamber. In one embodiment, the method includes flowing a first process gas into the chamber, the first process gas reacting with a metal-organic compound in the chamber to form a first volatile compound. In one embodiment, the method further includes flowing a second process gas into the chamber, the second process gas reacting with a pure metal of the metal-organic compound to form a second volatile compound. In one embodiment, the method further includes removing the second volatile compound from the chamber.

Description

[Technical Field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims priority to U.S. Patent Application No. 18 / 404,391, filed January 4, 2024, which claims the benefit of U.S. Provisional Application No. 63 / 548,355, filed November 13, 2023, and U.S. Provisional Application No. 63 / 444,858, filed February 10, 2023, the entire contents of which are incorporated herein by reference.

[0002] FIELD OF THE DISCLOSURE Embodiments of the present disclosure relate to the field of semiconductor processing, and in particular to a cluster tool integrating a dry develop chamber for extreme ultraviolet lithography (EUV) with metrology tools for after develop inspection (ADI) and after etch inspection (AEI). Embodiments also relate to a cleaning process for removing metal-organic particles from processing chambers and load locks. [Background technology]

[0003] Lithography has been used for decades in the semiconductor industry to create 2D and 3D patterns for microelectronic devices. The lithography process involves spin-on deposition of a film (photoresist), irradiating (exposing) the film with a selected pattern using an energy source, and then dissolving (developing) the exposed (positive tone) or unexposed (negative tone) areas of the film in a solvent. A bake is then performed to remove any remaining solvent.

[0004] Photoresist should be a radiation-sensitive material; when irradiated, a chemical change occurs in the exposed portions of the film, allowing for a change in solubility between the exposed and unexposed areas. This change in solubility is used to remove (develop) either the exposed or unexposed areas of the photoresist. This develops the photoresist, allowing the pattern to be transferred by etching into the underlying thin film or substrate. After the pattern is transferred, the remaining photoresist is removed, and this process can be repeated multiple times to create the 2D and 3D structures used in microelectronic devices.

[0005] Several properties are important in lithography processes. These properties include sensitivity, resolution, low line edge roughness (LER), etch resistance, and the ability to form thinner layers. The higher the sensitivity, the less energy is required to change the solubility of the deposited film. This can improve the efficiency of the lithography process. Resolution and LER determine how narrow features can be achieved in the lithography process. Pattern transfer to form deep structures requires materials with higher etch resistance. Materials with higher etch resistance also allow for thinner films. Thinner films improve the efficiency of the lithography process. Summary of the Invention

[0006] Embodiments disclosed herein include a method of cleaning a chamber. In one embodiment, the method includes flowing a first process gas into the chamber, the first process gas reacting with a metal-organic compound in the chamber to form a first volatile compound. In one embodiment, the method further includes flowing a second process gas into the chamber, the second process gas reacting with a pure metal of the metal-organic compound to form a second volatile compound. In one embodiment, the method further includes removing the second volatile compound from the chamber.

[0007]

[0006] Embodiments disclosed herein also include a method for cleaning a chamber having metal organic deposits on one or more interior surfaces. In one embodiment, the method includes flowing a first process gas into the chamber, the first process gas including hydrogen, where the hydrogen reacts with the metal organic deposits to form first volatile species, at least a portion of which decomposes to redeposit pure metal on the interior surfaces of the chamber. In one embodiment, the method further includes flowing a second process gas into the chamber, the second process gas including chlorine, where the chlorine reacts with the pure metal to form second volatile species.

[0008]

[0006] Embodiments disclosed herein also include a load lock. In one embodiment, the load lock comprises a chamber having sidewalls, a top, and a bottom, and a plurality of slot regions for supporting substrates. In one embodiment, the load lock further comprises a remote plasma source (RPS) and a plurality of lines between the RPS and the chamber. In one embodiment, each line couples the RPS to one of the plurality of slot regions. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a schematic diagram of a lithography tool including a track for depositing photoresist, a scanner for exposing the photoresist, and a metrology tool, according to an embodiment. [Figure 2] FIG. 1 is a schematic diagram of a lithography tool including a dry development chamber, an etch chamber, a metrology tool, and a dry deposition chamber, according to an embodiment. [Figure 3A] FIG. 1 illustrates a plan view of a cluster tool with a metrology tool, a development chamber, and an etch chamber on the front end module side, according to an embodiment. [Figure 3B]FIG. 1 illustrates a plan view of a cluster tool with a metrology tool, a development chamber, and an etch chamber at the opposite end from the front end module, according to an embodiment. [Figure 3C] FIG. 1 illustrates a plan view of a cluster tool including a metrology tool, a development chamber, and an etch chamber coupled to a front end module, according to an embodiment. [Figure 3D] FIG. 1 illustrates a plan view of a cluster tool with a shared metrology tool between two rows of development and etch chambers, according to an embodiment. [Figure 3E] FIG. 1 is a plan view of a cluster tool including a remote plasma source coupled to multiple development chambers, according to an embodiment. [Figure 3F] FIG. 1 illustrates a plan view of a cluster tool including a metrology tool, a development chamber, an etch chamber, and a deposition chamber, according to an embodiment. [Figure 4A] 1 is a cross-sectional view of a substrate having an underlayer on a surface of the substrate, according to an embodiment. [Figure 4B] 2 is a cross-sectional view of a substrate after providing a photoresist layer over an underlying layer, according to an embodiment. [Figure 4C] 1 is a cross-sectional view of a substrate during exposure of a photoresist layer, according to an embodiment. [Figure 4D] 1 is a cross-sectional view of a substrate after a photoresist layer has been developed, according to an embodiment. [Figure 4E] 1 is a cross-sectional view of a substrate during post-develop inspection (ADI), according to an embodiment. [Figure 4F] 3 is a cross-sectional view of a substrate after a pattern in a photoresist layer has been transferred to an underlying layer and the substrate, according to an embodiment. [Figure 4G] 1 is a cross-sectional view of a substrate during post-etch inspection (AEI), according to an embodiment. [Figure 5] FIG. 1 illustrates a process flow diagram of a photolithography process that is at least partially performed in a cluster tool that includes a development chamber, an etch chamber, and a metrology tool, according to an embodiment. [Figure 6]FIG. 1 is a flow diagram of a dry process for cleaning a chamber containing metal-organic particulates, according to an embodiment. [Figure 7A] FIG. 1 illustrates a plan view of a cluster tool including a remote plasma source (RPS) coupled to a processing chamber and a load lock, according to an embodiment. [Figure 7B] FIG. 10 is a cross-sectional view of a load lock coupled to an RPS, according to an embodiment. [Figure 8] 1 illustrates a block diagram of an exemplary computer system according to an embodiment of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0010] A cluster tool integrating a dry development chamber for extreme ultraviolet lithography (EUV) and metrology tools for post-development inspection (ADI) and post-etch inspection (AEI) is described. The following description sets forth numerous specific details for developing photoresist (such as thermal vapor processes and material regimes) to provide a comprehensive understanding of embodiments of the present disclosure. It will be apparent to those skilled in the art that embodiments of the present disclosure may be practiced without these specific details. In other instances, well-known aspects, such as integrated circuit fabrication, have not been described in detail so as not to unnecessarily obscure embodiments of the present disclosure. Furthermore, it should be understood that the various embodiments illustrated in the figures are illustrative representations and are not necessarily drawn to scale.

[0011] Specifically, photoresist systems used in extreme ultraviolet (EUV) lithography suffer from inefficiencies. Existing photoresist material systems for EUV lithography require high dosages to provide the solubility switch necessary to render the photoresist material developable. Chemically amplified resists (CARs) contain chemistries that are sensitive to EUV radiation. The chemical amplification concept uses photochemically generated acid as a catalyst. This catalyst initiates a chain reaction of chemical changes within the resist film, providing a gain mechanism to completely convert the exposed regions of the photoresist. The converted regions of the CAR then have etch selectivity over the unexposed regions. In this way, a development process can be used to remove the exposed regions while leaving the unexposed regions intact, or to remove the unexposed regions while leaving the exposed regions intact.

[0012] An additional class of photolithographic resists suitable for EUV lithography includes organic-inorganic hybrid materials (e.g., metal-oxo or metal-organic material systems). Such material systems are advantageous for EUV lithography due to their high sensitivity to EUV radiation. Such material systems typically contain a metal (e.g., Sn, Hf, Zr, etc.), oxygen, and carbon. In metal-oxo or metal-organic photoresist systems, exposure to EUV radiation causes cross-linking and carbon removal. The difference in carbon percentage between exposed and unexposed regions is used as a solubility switch during development. Specifically, in negative-tone development, unexposed regions with a high carbon content are preferentially etched by the developer. However, it should be understood that positive-tone development may also be used in some embodiments.

[0013] In many cases, resist deposition and exposure processes are provided in a single cluster tool, as shown in FIG. 1. For example, tool 100 may be used for resist deposition and exposure. Tool 100 may include track 104. Track 104 may include functionality for depositing a photosensitive resist material onto a substrate. For example, track 104 may dispense a liquid resist material onto the substrate. The substrate is then spun at a high rotations per minute (RPM) to evenly spread the resist material over the substrate. Track 104 may further include heating elements to bake the resist and prepare it for exposure.

[0014] The tool 100 may also include a scanner 102. The scanner 102 may be used to expose the resist to EUV radiation or other suitable radiation (e.g., deep ultraviolet (DUV)). The scanner 102 may be a stepper scanner or any other suitable scanning technology. After exposure, the substrate returns to the track 104, where a post-exposure bake (PEB), or the like, may be performed. In some embodiments, the PEB may be used to promote chemical reactions in the resist.

[0015] After the resist has been exposed, it must be developed. The development process may be carried out in a track 104 containing an etching environment. Typically, development is performed with wet etching chemistries. With small critical dimensions (CDs) and feature sizes, wet etching chemistries can have difficulty developing features due to their surface tension effects.

[0016] After the development process, the resulting structure is sent to a metrology tool for post-develop inspection (ADI). As used herein, ADI can refer to one or more of processes such as critical dimension (CD) metrology, overlay metrology, and defect inspection. In some cases, tool 100 may also include a metrology tool 106 to inspect the resist after exposure, PEB, and development. Metrology tool 106 may include the capability to image or otherwise analyze the resist. For example, metrology tool 106 may include any other relevant metrology system, such as scatterometry or scanning electron microscopy (CD-SEM). If the inspection meets all requirements, the substrate is sent to an etch chamber to transfer the resist pattern to the underlying substrate. The etch chamber may be located in a separate tool. This may require transport in a front-opening unified pod (FOUP), which removes the substrate from vacuum. After etching, the substrate may be sent back to the metrology tool to perform post-etch inspection (AEI). AEI can include both post-etch metrology (CD-SEM, scatterometry, etc.) and defect inspection, which can be performed in a stand-alone tool such as a brightfield inspection tool.

[0017] As can be seen from the process flow described above, to fully pattern a substrate using an EUV lithography process, the substrate must be moved between multiple tools and chambers. Accordingly, embodiments disclosed herein include a cluster tool architecture that achieves resist development, pattern transfer, and metrology all within a single tool architecture. More specifically, the development process can be performed using a dry development process, which enables smaller CDs and feature sizes. An all-in-one cluster tool can enable both ADI and AEI without leaving the vacuum environment, which allows for faster processing, improved results, and other efficiencies.

[0018] Additionally, embodiments disclosed herein utilize a dry cleaning process that can be used to periodically clean chambers, load locks, and the like. During processing of photoresist systems, particulates can accumulate on chamber surfaces. Without cleaning, the particulates can redeposit on subsequently processed substrates, causing defects and other damage. In the case of metal-organic photoresist systems, the particulates will generally include metal-organic compounds. Existing cleaning processes (e.g., using NF3) do not provide volatile compounds that can be removed from the chamber, especially when the metal component includes tin. Therefore, a new cleaning process flow is disclosed herein.

[0019] Generally, a first process gas (with or without plasma) is flowed into the chamber. The first process gas can volatilize the metal-organic particulates and be exhausted from the chamber. However, some amount of pure metal may be redeposited on the chamber surfaces. Therefore, a second process gas (with or without plasma) is flowed into the chamber and reacts with the pure metal to form volatile compounds that can be removed from the chamber. In some embodiments, the first process gas and the second process gas can include one or more of hydrogen, chlorine, and bromine. Also, in some embodiments, oxygen and an inert gas (e.g., argon, helium, nitrogen, etc.) can be added to the process gas.

[0020] Referring now to FIG. 2 , a plan view of a cluster tool 200 is shown, according to an embodiment. In one embodiment, the cluster tool 200 may include a development chamber 210. More specifically, the development chamber 210 may be a dry development chamber 210. In this manner, the exposed resist layer can be developed with a dry etch process that improves LER, LWR, CD, and overall feature size. The development chamber 210 may be any chamber suitable for a dry development process. For example, the dry development chamber 210 may be a plasma chamber. When a plasma is generated, the plasma reacts with and removes exposed or unexposed regions of the resist, depending on whether the resist is a positive or negative resist.

[0021] In one embodiment, the cluster tool 200 may further include an etch chamber 212. The etch chamber 212 may also be a plasma etcher. The etch chamber 212 performs a dry etching process to transfer the pattern of the resist layer to an underlying layer of the substrate (e.g., a silicon layer, an oxide layer, a nitride layer, a metal layer, or any other layer suitable for semiconductor processing). In more particular embodiments, the underlying layer may include any number of layers. For example, the underlying layer may include a hard mask (e.g., tin-based), a hard mask (e.g., silicon carbide), and a device stack that requires patterning.

[0022] In one embodiment, the cluster tool 200 may further include a metrology tool 206. The metrology tool 206 may be used to detect overlay error, LER, LWR, CD, or any other parameter of the resist or patterned substrate. In a particular embodiment, the cluster tool 200 may include a scatterometry tool. The metrology tool 206 may be used to provide ADI or AEI. The metrology tool 206 is integrated with the etch chamber 212 and the develop chamber 210 in the cluster tool 200, so the substrate does not need to leave the vacuum environment during processing.

[0023] As one general example of a potential process flow through a cluster tool, the process may begin with a pattern being formed in resist in a dry develop chamber 210. ADI may then be performed by the metrology tool 206. Etching of the substrate then proceeds in the etch chamber 212. In some embodiments, the etch chamber 212 may etch an underlayer and a hard mask in the same chamber. After etching the underlayer and hard mask, AEI is performed by the metrology tool 206 to confirm that the etch pattern is properly formed. Once confirmed, the substrate may be returned to the etch chamber 212 for additional etching to etch the device stack.

[0024] In one embodiment, the cluster tool 200 may further include a dry deposition tool 215. The dry deposition tool 215 may be used to coat a resist on a substrate using a deposition process such as chemical vapor deposition (CVD), atomic layer deposition (ALD), or the like.

[0025] In one embodiment, the cluster tool 200 is generally depicted as a simple box, with no connections between the metrology tool 206, the develop chamber 210, and the etch chamber 212. However, there are transfer chambers and the like between these components, as will be described in more detail below. For example, load locks, robotic transfer chambers, and the like may be provided between chambers and tools within the cluster tool 200. There may also be an equipment front end module (EFEM) for receiving a FOUP or the like. Additionally, while FIG. 2 includes multiple chamber types, it should be understood that an embodiment may include only the metrology tool 206 and the dry develop chamber 210.

[0026] 3A-3F, a series of plan views illustrating the layout of various cluster tools 300 are shown, according to embodiments. As will be appreciated from the following description, the individual components (e.g., metrology tools, develop chambers, etch chambers, etc.) can be arranged in many different configurations while still maintaining the benefits of being part of a single cluster tool architecture. The cluster tools 300 below are shown generally in boxes. Those skilled in the art will recognize that complex features (e.g., slit valves, exhaust solutions, robotic handling equipment, plasma sources, etc.) have been omitted to more clearly depict the general layout of the cluster tool 300.

[0027] 3A, a plan view of a cluster tool 300 is shown, according to an embodiment. In one embodiment, the cluster tool 300 may include an EFEM 321. The EFEM 321 may receive a FOUP, cassette, or the like as an entry point for substrates into the cluster tool 300. Substrates processed in the cluster tool 300 may include wafers (e.g., silicon wafers or other semiconductor wafers) of any standard form factor (e.g., 200 mm, 300 mm, 450 mm, etc.). In one embodiment, the EFEM 321 may be coupled to the rest of the cluster tool 300 through a load lock 322. The load lock 322 may isolate atmospheric conditions within the EFEM from vacuum conditions in the rest of the cluster tool 300. However, in some embodiments, the EFEM may also be under vacuum pressure (e.g., a higher pressure than the other side of the load lock 322).

[0028] In one embodiment, a metrology tool 325 may be provided after the load lock 322. The metrology tool 325 may be a scatterometry tool or any other metrology tool useful for ADI or AEI applications. In one embodiment, the metrology tool 325 may be communicatively coupled to a transfer chamber 327. The transfer chamber 327 may include a robotic arm, a track, or any suitable architecture for transporting substrates between the metrology tool 325 and the rest of the cluster tool 300.

[0029] In one embodiment, the transfer chamber 327 may be coupled to one or more developer chambers 310 and one or more etch chambers 312. For example, the cluster tool 300 may be equipped with six developer chambers 310 and four etch chambers 312. The chambers 310 and 312 may be located on two sides of the transfer chamber 327 to optimize space savings. In one embodiment, the developer chamber 310 may be a dry developer chamber. A plasma source may be used in combination with the developer chamber 310 to develop the resist layer without the use of wet chemistries. However, it will be understood that a dry developer process does not require a plasma source. That is, a dry developer process may or may not use a plasma source. If a plasma source is not used, the dry developer process may be a thermal dry developer process in some embodiments. A plasma source may also be used to clean the developer chamber 310 and reduce tin contamination. For example, in some embodiments, a plasma etch chemistry including one or more of F2, NF3, Cl2, O2, and HBr may be used to clean the development chamber 310. Furthermore, while tin contamination is provided as an example of a material to be cleaned from the chamber, it should be understood that other metals may also pose a contamination risk. Thus, depending on the type of photoresist material being used, a plasma source may also be used to clean other metals. Furthermore, the etch chamber 312 may be a dry etch chamber 312 that uses a plasma to etch the substrate through the resist layer.

[0030] In one embodiment, a substrate enters the EFEM, passes through load lock 322 and metrology tool 325, and is sent to one of the development chambers 310. After development, the substrate is sent to metrology tool 325 for ADI. After ADI, the substrate may be sent through transfer chamber 327 to one of the etching chambers 312, where the substrate may be etched through the developed resist layer. The substrate may then be returned to metrology tool 325 for AEI. Thus, the resist development, ADI, substrate etch, and AEI steps may be performed within a single cluster tool 300 without having to leave the vacuum environment.

[0031] 3B, a plan view of a cluster tool 300 according to an additional embodiment is shown. The cluster tool 300 may be similar to the cluster tool 300 described in more detail above, except for the metrology tool 325. The metrology tool 325 is at the end of the cluster tool 300 opposite the EFEM 321, rather than between the load lock 322 and the transfer chamber 327. That is, the load lock 322 may be directly coupled to the transfer chamber 327. In such an embodiment, substrates may be inserted and removed from the cluster tool 300 without passing through the metrology tool 325. While the metrology tool 325 is shown at the end of the transfer chamber 327, it will be understood that the metrology tool 325 may be coupled to the transfer chamber 327 anywhere along the transfer chamber 327.

[0032] Referring now to FIG. 3C , a cross-sectional view of a cluster tool 300 is shown in accordance with an additional embodiment. In one embodiment, the cluster tool 300 of FIG. 3C may be similar to the cluster tool 300 of FIG. 3A , except for the positioning of the metrology tool 325. In one embodiment, the metrology tool 325 may be directly coupled to the EFEM 321. For example, the metrology tool 325 may be located along an edge of the EFEM 321. This allows substrates to be transported directly from a FOUP, through the EFEM 321, to the metrology tool 325 without having to pass through the load lock 322. In one embodiment, the develop chamber 310 and the etch chamber 312 may be on opposite sides of the load lock 322 from the metrology tool 325. In some embodiments, both the resist may be developed and the substrate may be etched before the substrate passes through the load lock 322 and returns to the metrology tool 325.

[0033] Referring now to FIG. 3D , a plan view of a cluster tool 300 according to an additional embodiment is shown. In the embodiment shown in FIG. 3D , a metrology tool 325 is shared between a first processing line and a second processing line. The first processing line may include a first EFEM 321A, a first load lock 322A, and a first transfer chamber 327A. The development chamber 310 and the etch chamber 312 may be coupled to the first transfer chamber 327A. The second processing line may include a second EFEM 321B, a second load lock 322B, and a second transfer chamber 327B. The development chamber 310 and the etch chamber 312 may be coupled to the second transfer chamber 327B. As shown, the metrology tool 325 is coupled to both the first EFEM 321A and the second EFEM 321B. The overall structure of the cluster tool 300 may be U-shaped. The first processing line forms a first arm, the second processing line forms a second arm, and the metrology tool 325 forms a junction between the first and second arms.

[0034] Referring now to FIG. 3E, a plan view of a cluster tool 300 according to an additional embodiment is shown. The cluster tool 300 of FIG. 3E may be similar to the cluster tool 300 of FIG. 3C, but with the addition of a remote plasma source (RPS) 313. As shown, a pair of RPSs 313 may be coupled to the cluster tool 300. For example, each of the RPSs 313 may be fluidly coupled to multiple developer chambers 310. By moving the plasma source from the developer chambers to the RPSs 313, the developer chambers 310 may be simplified, and a single RPS 313 may be used for multiple developer chambers 310, further simplifying the design and maintenance of the cluster tool 300. While not shown as including an RPS 313, it should be understood that an RPS 313 solution may also be used to supply plasma to one or more etch chambers 312. The RPS 313 may be used to assist the developer process in the developer chamber 310. However, in other embodiments, the developer process is a dry process without plasma, such as a thermal dry developer process. In such cases, the RPS 313 may be used to clean the developer chamber 310. For example, in some embodiments, plasma chemistries including one or more of F, NF, Cl, O, and HBr may be used to clean the developer chamber 310.

[0035] Referring now to FIG. 3F, a plan view of a cluster tool 300 according to an additional embodiment is shown. The cluster tool 300 of FIG. 3F may be substantially similar to the cluster tool 300 of FIG. 3C, but with the addition of one or more deposition chambers 315. In one embodiment, the deposition chamber 315 may be used to deposit a photolithography resist layer on a substrate. To minimize waste, improve resist uniformity, and / or provide a composition gradient through the thickness of the resist layer, the deposition chamber 315 may be a dry deposition chamber. For example, an atomic layer deposition (ALD) process or a chemical vapor deposition (CVD) process may be used to deposit the resist layer. In one embodiment, one or more metal-containing precursors (and optionally an oxidizer) may be reacted in the deposition chamber 315 to deposit a resist layer on the substrate. The resist layer may be a chemically amplified resist (CAR) system or a metal-oxo resist system.

[0036] 4A-4G, a process for forming a pattern on a substrate using a cluster tool is shown, according to an embodiment. In one embodiment, a pattern can be transferred to the substrate using an exposed and developed photoresist layer. The photoresist layer can be CAR or metal oxo resist in some embodiments. In certain embodiments, the treatment can include EUV exposure, DUV exposure, or any other suitable electromagnetic radiation.

[0037] Referring now to FIG. 4A , a cross-sectional view of a substrate 450 is shown, according to an embodiment. In one embodiment, the substrate 450 may be a semiconductor substrate such as a silicon wafer. The illustrated substrate 450 may also be any layer used in a semiconductor manufacturing environment. For example, the substrate 450 may comprise an oxide, nitride, metal, or any other material composition that needs to be patterned in a lithography process. In one embodiment, an underlayer 451 may be provided on the top surface of the substrate 450. The underlayer 451 may be a material that facilitates etching of the substrate 450. In some embodiments, the underlayer 451 may be a hard mask layer, or the like.

[0038] 4B, a cross-sectional view of substrate 450 is shown after providing resist layer 460 on underlayer 451, according to an embodiment. In one embodiment, resist layer 460 can be a CAR system or a metal-oxo system. Resist layer 460 can be deposited with a wet coating process (e.g., spin coating) or a dry coating process (e.g., ALD or CVD). In one embodiment, the coating process can be performed in a cluster tool or as part of a track coupled to a lithography tool.

[0039] 4C, a cross-sectional view of substrate 450 during exposure is shown, according to an embodiment. In one embodiment, the exposure is through a mask 466. The exposure may be EUV, DUV, or the like. The exposed portions (indicated by arrows) that pass through mask 466 react with resist 460 to form exposed regions 465. The exposed regions may be fully converted and have etch selectivity relative to the remainder of resist 460. In some embodiments, a post-exposure bake (PEB) may be used to fully convert exposed regions 465.

[0040] 4D, a cross-sectional view of substrate 450 is shown after resist 460 has been developed, according to an embodiment. In one embodiment, the development process may be performed in a cluster tool, such as cluster tool 300, described in more detail above. The development process may be a dry development process, which may or may not include the use of plasma. The dry development process may remove unexposed portions. However, exposed regions 465 may optionally be removed in an opposite-tone resist instead of the unexposed regions of resist 460.

[0041] 4E, a cross-sectional view of a substrate 450 is shown when the substrate is placed in a metrology tool 425, according to an embodiment. The metrology tool 425 may be part of a cluster tool that includes a development chamber. As such, the substrate 450 does not need to be removed from the vacuum environment to perform the ADI process. The ADI may include scatterometry or any other type of metrology used to inspect the results of the development process.

[0042] 4F, a cross-sectional view of a substrate 450 after a pattern transfer process is shown, according to an embodiment. In one embodiment, the pattern transfer process may be performed in an etch chamber coupled to a metrology tool 425 and a development chamber. The etch chamber may be a dry etch chamber that uses a plasma to etch the underlying layer 451 and the substrate 450 to form features 454 (e.g., trenches, lines, etc.). Although referred to as an "etch chamber," it should be understood that the pattern transfer process may include both an etch process and a deposition process (e.g., a sidewall deposition process).

[0043] 4G, a cross-sectional view of a substrate 450 is shown after the substrate has been transferred to a metrology tool 425, according to an embodiment. The metrology tool may be the same tool used for ADI. However, embodiments may also include a different metrology tool 425 than that used for ADI. The metrology tool 425 shown in FIG. 4G may be used to perform AEI. The metrology may include scatterometry, etc. After AEI, the substrate 450 may be removed from the cluster tool for additional processing or inspection.

[0044] 5, a flow diagram of a process 570 is shown, according to an embodiment. In one embodiment, the process 570 may begin with a photoresist exposure process. The exposure process may be performed in a scanner 502, such as an EUV or DUV scanner. After the resist layer is exposed, it may be baked or otherwise processed. The substrate with the exposed photoresist is then transferred to a cluster tool 500. The cluster tool 500 may include a developer 510, such as a development chamber. The developer 510 may be a dry development tool that uses plasma to develop the exposed photoresist.

[0045] After development, the substrate may be moved to a metrology tool 525 for the ADI. The ADI may provide feedback 571 back to the scanner 502 to improve the performance of the scanner 502. Additionally, the ADI may provide feedforward data 572 to the etcher 512. The feedforward data may be used to control the etch process to account for certain errors in the development process. The metrology tool 525 may also be within the cluster tool 500.

[0046] After ADI, the substrate is sent to etcher 512. Etcher 512 may be located within cluster tool 500. Etcher 500 transfers the pattern of the photoresist to the substrate. For example, in some embodiments, a dry etching process may be used.

[0047] After etching, the substrate is returned to the metrology tool 525 for AEI. The AEI process may provide feedback 573 back to the etcher 512 and / or feedback 574 back to the scanner 502. In-line metrology (either AEI or AEI) provides denser sampling and faster feedback and / or feedforward loops. Thus, the cluster tools described herein improve the accuracy and speed of substrate processing compared to conventional processes.

[0048] Feedback and feedforward process loops may be suitable for any type of system control. In one embodiment, automatic process control (APC) may be performed with a process similar to that described above with respect to Figure 5. Similarly, defect classification (FDC) may be performed using a process similar to that described above with respect to Figure 5.

[0049] As discussed above, processing (e.g., developing, etc.) of photoresist systems can result in the formation of particulate deposits on chamber surfaces. Without periodic and proper cleaning, these particulates can cause damage or defects in subsequently processed substrates. Accordingly, embodiments disclosed herein include cleaning processes that can be used to reduce or eliminate particle redeposition on substrates.

[0050] Generally, the cleaning processes described herein can be characterized as dry cleaning processes. That is, cleaning is performed through the use of one or more processing gases. In some embodiments, the processing gases are radicalized through the use of a plasma. The plasma can be any type of plasma. For example, the plasma can include an in-situ plasma source, a remote plasma source (RPS), a microwave plasma source, a capacitively coupled plasma (CCP) source, an inductively coupled plasma (ICP) source, a transformer coupled toroidal plasma (TCTP) source, etc. However, in some embodiments, a thermal cleaning process (i.e., not including a plasma) can also be used.

[0051] In one embodiment, the cleaning process may be provided in any of the chambers within a cluster tool similar to any of the cluster tools described in more detail herein. In a particular embodiment, the cleaning process may be performed within a photoresist development chamber. In other embodiments, the cleaning process may be used to clean chambers used for substrate transport, such as load locks or transfer chambers.

[0052] 6, a process flow diagram illustrating a process 640 for cleaning a chamber is shown, according to an embodiment. In one embodiment, process 640 may be performed at any desired frequency. For example, process 640 may be performed after a certain number of substrates have been processed (e.g., 1 substrate, 5 substrates, 20 substrates, etc.), after a certain amount of time (e.g., every hour, every 3 hours, at the start of a shift, daily, etc.), after contaminants are detected on processed substrates, or after other time periods or suitable criteria have been met.

[0053] In one embodiment, process 640 may target cleaning of metal-organic compounds deposited on chamber surfaces. The metal-organic compounds may be derived from a photoresist system. The photoresist system may be a DUV or EUV photoresist, such as a metal-oxo system, a metal-organic system, or the like. In one embodiment, the metal component may include one or more of Sn, Hf, Zr, or other suitable metal elements. The metal may be combined with an organic element (such as carbon, oxygen, hydrogen, or nitrogen). Suitable process gases for removing metal components may include hydrogen, chlorine, bromine, or the like.

[0054] In one embodiment, process 640 may begin at step 641, which includes flowing a first process gas into the chamber. In one embodiment, the first process gas reacts with a metal-containing compound to form a first volatile compound. The first process gas may include hydrogen, chlorine, chlorine trifluoride, or bromine. The use of hydrogen may be particularly beneficial in the case of tin-based metal-organic compounds. Hydrogen (H2) may react with tin to form the volatile compound SnH4 through the chemical reaction Sn + 2H2 → SnH4. Hydrogen may also preferentially react with organic components to form volatile species. For example, 2H+SnO→Sn+H2O Unfortunately, SnH4 will tend to spontaneously decompose to pure tin through the chemical reaction SnH4 → Sn + 2H2. However, the decomposition may also produce other Sn-containing materials through reactions with other species in the chamber. Thus, process 640 may include additional steps, as described in more detail below.

[0055] In one embodiment, hydrogen can be flowed into the chamber in a thermal process that does not include plasma activation. Alternatively, a plasma can be used to radicalize hydrogen to improve reactivity with metal-organic compounds. The plasma source can be any suitable plasma source, as described in more detail above. In embodiments with an RPS, oxygen can be flowed along with the hydrogen to improve hydrogen radicalization within the RPS. An inert gas (such as argon, helium, or nitrogen) can also be flowed along with the hydrogen to support a more stable plasma.

[0056] In one embodiment, process 640 may continue with step 642, which includes purging the first volatile compound from the chamber. The first volatile compound may be purged with any suitable exhaust or vacuum pump configuration. The first volatile compound may include hydrogen reacted with organic compounds and some amount of metal element (e.g., tin). However, as discussed above, some amount of pure metal element (in solid form) or other metal-containing solids may remain in the chamber.

[0057] In one embodiment, process 640 may continue with step 643, which includes flowing a second process gas into the chamber. The second process gas reacts with the metal to form a second volatile compound. In one embodiment, the second process gas is a different process gas from the first process gas. For example, if the first process gas includes hydrogen, the second process gas may include chlorine, chlorine trifluoride, or bromine. In the case of chlorine, the chemical reaction may include Sn + Cl → SnCl, where SnCl is a volatile compound. In one embodiment, step 643 may be performed with or without a plasma (e.g., a thermal cleaning step). The second process gas may include only chlorine or may include chlorine plus oxygen and / or an inert gas (e.g., argon, helium, nitrogen, etc.).

[0058] In one embodiment, process 640 may continue with step 644, which includes purging the second volatile compound from the chamber. The second volatile compound may be purged with any suitable evacuation or vacuum pump configuration. The second volatile compound may include chlorine reacted with a pure metal element (e.g., tin) or other metal-containing material.

[0059] In one embodiment, process 640 can be performed sequentially. That is, steps 641-644 can be performed one after the other. For example, a first pulse of a first process gas can be flowed into the chamber followed by a second pulse of a second process gas. The purge step 642 between the two pulses can also be omitted in some embodiments. In one embodiment, the first and second pulses can be of the same duration, or the first and second pulses can have different durations. The duration of the first and second pulses can range from a few seconds to one minute or more (e.g., one minute, five minutes, ten minutes, etc.). In one embodiment, process 640 can be repeated any number of times. For example, steps 641-644 can be cycled two or more times to provide the desired level of cleaning. While a sequential process can be beneficial for some cleaning processes, embodiments can also include flowing both the first and second process gases simultaneously.

[0060] In one embodiment, the process conditions used during cleaning process 640 can be similar to the process conditions used to process the substrate. Therefore, no significant changes in temperature or pressure are required during cleaning. This allows for faster cleaning operations and increased throughput. For example, the temperature (e.g., wafer temperature) during process 640 can be between about 20°C and about 100°C, and the pressure during process 640 can be between about 1 mTorr and about 10 Torr. The process gas flow rate can be between about 10 sccm and 5000 sccm during steps 641-644.

[0061] 6, process 640 includes two separate process gas flows. However, in other embodiments, sufficient cleaning may be achieved through the use of a single process gas. For example, the use of radicalized hydrogen may be sufficient to remove the desired amount of residual deposits on the chamber surfaces. A longer cleaning duration (compared to a two-gas process) may be required, or the single-gas process may be performed more frequently.

[0062] 7, a plan view of a cluster tool 700 is shown in accordance with an additional embodiment. The cluster tool 700 of FIG. 7 may be similar to the cluster tool 700 of FIG. 3E, with the addition of an RPS 713 coupled to a load lock 722 and a transfer chamber 727 by lines 717 and 714, respectively. That is, the cluster tool 700 may include an EFEM 721 and a metrology tool 725 coupled to the transfer chamber 727 through the load lock 722. The develop chamber 710 and the etch chamber 712 may also be coupled to the transfer chamber 727.

[0063] As shown, a pair of RPSs 713 may be coupled to the cluster tool 700. For example, each of the RPSs 713 may be fluidly coupled to multiple developer chambers 710. By moving the plasma source from the developer chambers to the RPSs 713, the developer chambers 710 may be simplified, and a single RPS 713 may be used for multiple developer chambers 710, further simplifying the design and maintenance of the cluster tool 700. While not shown as including an RPS 713, it should be understood that an RPS 713 solution may also be used to supply plasma to one or more etch chambers 712. The RPSs 713 may be used to assist the developer process in the developer chambers 710. However, in other embodiments, the developer process is a dry process without plasma, such as a thermal dry developer process.

[0064] In some embodiments, the RPS 713 may be used to clean the developer chamber 710, the load lock 722, the etch chamber 712, or the transfer chamber 727. For example, a cleaning process such as process 640 may be performed using the RPS 713 to periodically clean one or more of the developer chamber 710, the load lock 722, the etch chamber 712, and the transfer chamber 727. That is, similar to the embodiment described in more detail above, a sequence of two process gases (e.g., hydrogen followed by chlorine) may be used to clean metal organic deposits from the interior chamber surfaces.

[0065] 7B, a cross-sectional view of a portion of a load lock 722 is shown, according to an embodiment. The load lock 722 may include a chamber 780. The chamber 780 may be divided into multiple slot regions by supports 781. A substrate 785 may be placed on the supports 781. A robot arm 782 may be provided within the load lock 722 to move the substrate 785 into and out of the load lock 722. A pump feature 783 (e.g., exhaust, vacuum, etc.) may also be provided within the load lock 722.

[0066] The presence of multiple supports 781 makes it difficult to clean many areas of the load lock 722 using conventional cleaning solutions. However, because the RPS 713 solution is used, multiple feeds can be supplied to the chamber 780. For example, each slot region can be supplied with a dedicated feed line 717. In one embodiment, a distribution plate 786 is provided at the end of each feed line 717 to more evenly distribute radicalized species from the plasma. In the illustrated embodiment, the feed lines 717 enter the chamber 780 through the sidewall. In this way, each slot region can be accessed without being shadowed by the upper supports 781 (as would occur if the feed lines 717 were introduced from the top of the chamber 780 using more conventional approaches).

[0067] FIG. 8 shows a schematic diagram of a machine in the exemplary form of a computer system 800 within which a set of instructions for causing the machine to perform any one or more of the methodologies described herein may be executed. In alternative embodiments, the machine may be connected (e.g., networked) to other machines in a local area network (LAN), an intranet, an extranet, or the Internet. The machine may operate as a server or a client machine in a client-server network environment, or as a peer machine in a peer-to-peer (or distributed) network environment. The machine may be a personal computer (PC), a tablet PC, a set-top box (STB), a personal digital assistant (PDA), a mobile phone, a web appliance, a server, a network router, switch, or bridge, or any machine capable of executing a set of instructions (sequential or otherwise) that specify actions to be performed by the machine. Furthermore, while only a single machine is illustrated, the term "machine" is intended to include any collection of machines (e.g., computers) that individually or jointly execute a set of instructions (or sets) to perform any one or more of the methodologies described herein.

[0068] The exemplary computer system 800 includes a processor 802, a main memory 804 (e.g., read-only memory (ROM), flash memory, dynamic random access memory (DRAM) (e.g., synchronous DRAM (SDRAM) or Rambus DRAM (RDRAM)), etc.), a static memory 806 (e.g., flash memory, static random access memory (SRAM), MRAM, etc.), and a secondary memory 818 (e.g., a data storage device, etc.), which communicate with each other via a bus 830.

[0069] Processor 802 represents one or more general-purpose processing devices, such as a microprocessor, a central processing unit, or the like. More specifically, processor 802 may be a complex instruction set computing (CISC) microprocessor, a reduced instruction set computing (RISC) microprocessor, a very long instruction word (VLIW) microprocessor, a processor implementing other instruction sets, or a processor implementing a combination of instruction sets. Processor 802 may also be one or more special-purpose processing devices, such as an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA), a digital signal processor (DSP), a network processor, or the like. Processor 802 is configured to execute processing logic 826 for performing the operations described herein.

[0070] Computer system 800 may further include a network interface device 808. Computer system 800 may also include a video display unit 810 (e.g., a liquid crystal display (LCD), a light emitting diode display (LED), or a cathode ray tube (CRT)), an alphanumeric input device 812 (e.g., a keyboard), a cursor control device 814 (e.g., a mouse), and a signal generating device 816 (e.g., a speaker).

[0071] The secondary memory 818 may include a machine-accessible storage medium (or more specifically, a computer-readable storage medium) 832 having stored thereon one or more sets of instructions (e.g., software 822) that embody any one or more of the methods or functions described herein. The software 822 may also reside, completely or at least partially, within the main memory 804 and / or the processor 802 during execution by the computer system 800. The main memory 804 and the processor 802 also constitute machine-readable storage media. The software 822 may further be transmitted or received over the network 820 via the network interface device 808.

[0072] While the exemplary embodiment depicts machine-accessible storage medium 832 as a single medium, the term "machine-readable storage medium" should be interpreted to include a single medium or multiple media (e.g., a centralized or distributed database, and / or associated caches and servers) that store one or more sets of instructions. The term "machine-readable storage medium" should also be interpreted to include any medium capable of storing or encoding a set of instructions that are executable by a machine and cause the machine to perform any one or more of the methodologies of the present disclosure. Thus, the term "machine-readable storage medium" should be interpreted to include, but is not limited to, solid-state memory, optical media, and magnetic media.

[0073] According to one embodiment of the present disclosure, a machine-accessible storage medium has stored thereon instructions for causing a data processing system to execute a method for exposing a photoresist, performing an SIS process on the photoresist, developing the photoresist, and etching an underlying substrate. The process is performed at least in part in a cluster tool. The cluster tool may include a metrology tool, a development chamber, and an etch chamber. In one embodiment, the method disclosed herein enables improved feedback and / or feedforward control of the development and etch processes for improved speed and accuracy compared to conventional methods.

[0074] Thus, a method for processing a substrate in a cluster tool comprising a metrology tool, a dry development chamber, and an etch chamber has been described.

Claims

1. 1. A method for cleaning a chamber, comprising: flowing a first process gas into the chamber, the first process gas reacting with a metal organic compound in the chamber to form a first volatile compound; removing the first volatile compound from the chamber; flowing a second process gas into the chamber, the second process gas reacting with the pure metal of the metal-organic compound to form a second volatile compound; removing the second volatile compound from the chamber; and A method comprising:

2. The method of claim 1 , wherein the first process gas comprises hydrogen.

3. The method of claim 2 , wherein the second process gas comprises chlorine trifluoride, chlorine, or bromine.

4. The method of claim 1 , wherein the first process gas and / or the second process gas are radicalized by a plasma source.

5. 5. The method of claim 4, wherein the plasma source is an in-situ plasma source, a remote plasma source (RPS), a microwave plasma source, a capacitively coupled plasma (CCP) source, an inductively coupled plasma (ICP) source, or a transformer coupled toroidal plasma (TCTP) source.

6. 10. The method of claim 1, wherein the first process gas and / or the second process gas comprises oxygen and one or more of hydrogen, chlorine trifluoride, chlorine, and bromine.

7. The method of claim 1 , wherein the first process gas and the second process gas are flowed into the chamber sequentially.

8. The method of claim 1 , wherein the metal organic compound comprises tin and oxygen.

9. 10. The method of claim 1, wherein the chamber is a chamber in a cluster tool including two or more of a metrology tool, a front end module, a development chamber, an etch chamber, or a deposition chamber, and the chamber is a photoresist development chamber, a photoresist deposition chamber, a wafer transfer chamber, or a load lock.

10. The method of claim 1 , wherein the first process gas and / or the second process gas further comprises one or more of argon, helium, and nitrogen.

11. 1. A method for cleaning a chamber having metal organic deposits on one or more interior surfaces, comprising: flowing a first process gas into the chamber, the first process gas comprising hydrogen, the hydrogen reacting with the metal organic deposit to form first volatile species, at least a portion of the first volatile species decomposing to redeposit metal-containing material on the interior surfaces of the chamber; flowing a second process gas into the chamber, the second process gas comprising chlorine, the chlorine reacting with the metal-containing material to form a second volatile species; A method comprising:

12. The method of claim 11 , wherein the first process gas and / or the second process gas are radicalized by a plasma source.

13. The method of claim 11 , wherein the first process gas and / or the second process gas further comprises oxygen.

14. 12. The method of claim 11, wherein the wafer temperature in the chamber is between 20°C and 100°C.

15. 12. The method of claim 11, wherein the pressure in the chamber is between 1 mTorr and 10 Torr.

16. 12. The method of claim 11, wherein the chamber is a chamber in a cluster tool that includes two or more of a metrology tool, a front end module, a development chamber, an etch chamber, or a deposition chamber, and the chamber is a photoresist development chamber, a photoresist deposition chamber, a wafer transfer chamber, or a load lock.

17. A load lock, a chamber having a sidewall, a top, and a bottom; a plurality of slot areas for supporting a substrate; a remote plasma source (RPS); and a plurality of lines between the RPS and the chamber, each line coupling the RPS to one of the plurality of slot regions; A load lock comprising:

18. The load lock of claim 17 , wherein the line passes through the sidewall of the chamber.

19. The load lock of claim 18 , wherein each line terminates in a distribution plate within one of the slot regions.

20. 20. The load lock of claim 17, wherein the load lock is part of a cluster tool that includes two or more of a metrology tool, a front end module, a development chamber, an etch chamber, or a deposition chamber.

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