A method for measuring and identifying vacuum contamination in a chamber of any size in situ.

Abstract

System 100 includes a primary vacuum chamber 110 and a secondary vacuum chamber 120 connected to the primary vacuum chamber 110 via a gate valve 115. The gate valve 115 operates between an open position, in which the secondary vacuum chamber 120 is in fluid communication with the primary vacuum chamber 110, and a closed position, in which the secondary vacuum chamber 120 is sealed from the primary vacuum chamber 110. A heat exchanger 130 cools the secondary vacuum chamber 120 when the gate valve 115 is in the open position to adsorb contaminants 102 from the primary vacuum chamber 110 into the secondary vacuum chamber 120. A gas source 140 injects a carrier gas into the secondary vacuum chamber 120 when the gate valve 115 is in the closed position. The heat exchanger 130 also heats the carrier gas in the secondary vacuum chamber 120 to desorb the contaminants 102, which then combine with the carrier gas to form a gas sample. A sample container 145 collects the gas sample from the secondary vacuum chamber 120.

Description

Technical Field

[0001] Cross-Reference to Related Applications This application claims priority to U.S. Provisional Patent Application No. 63 / 538,504 filed on September 15, 2023 and U.S. Provisional Patent Application No. 63 / 675,094 filed on July 24, 2024, the disclosures of which are hereby incorporated by reference into this application in their entireties.

[0002] The present disclosure relates to semiconductor manufacturing, and more specifically, to the use of vacuum chambers in fabrication processes and inspection processes.

Background Art

[0003] Advances in the semiconductor manufacturing industry are placing increasingly greater demands on yield management, and in particular on metrology and inspection systems. Critical dimensions continue to shrink, yet the industry still requires reduced time to achieve high-yield, high-value production. Minimizing the total time from detection of a yield issue to its correction determines the return on investment for semiconductor manufacturers.

[0004] Fabrication of semiconductor devices, such as logic devices and memory devices, generally involves processing workpieces such as semiconductor wafers using a number of fabrication steps to form various features and multiple layers of the semiconductor devices. For example, lithography is a semiconductor fabrication process that involves transferring a pattern from a reticle to a photoresist disposed on a semiconductor wafer. Additional examples of semiconductor fabrication processes include, but are not limited to, chemical mechanical polishing (CMP), etching, film deposition, and ion implantation. An array of multiple semiconductor devices fabricated on a single semiconductor wafer can be separated into individual semiconductor devices.

[0005] To promote higher yields in the manufacturing process and the resulting higher profits, inspection processes are used at various steps in semiconductor manufacturing to detect defects on the wafer. Inspection is always an important part of the fabrication of semiconductor devices such as integrated circuits (ICs). However, as the dimensions of semiconductor devices decrease, inspection becomes even more crucial for successfully manufacturing acceptable semiconductor devices, as even smaller defects can cause malfunctions. For example, as the dimensions of semiconductor devices decrease, the detection of smaller defects becomes necessary, as even relatively small defects can cause undesirable anomalies in semiconductor devices.

[0006] However, as design rules become smaller, semiconductor manufacturing processes may be operating closer to the limits of their performance capabilities. Furthermore, as design rules become smaller, smaller defects can affect the electrical parameters of the device, thus requiring more sensitive inspection. As design rules become smaller, the population of defects that may be yield-related and can be detected by inspection increases dramatically, as does the population of undesirable defects detected by inspection. This may result in more defects being detected on the wafer, and modifying the process to eliminate all defects can be difficult and costly. By determining which defects actually affect the electrical parameters and yield of the device, it may be possible to focus process control methods on those defects and ignore the majority of other defects. Moreover, with smaller design rules, process-related defects sometimes tend to occur systematically. That is, process-related defects tend to occur in a given pattern of the design, often repeated many times within a given design. Systematic elimination of electrical-related defects in space can affect yield.

[0007] To minimize environmental factors that could cause defects in workpieces, manufacturing and inspection processes are often carried out in controlled environments, such as sealed vacuum chambers. However, even in such "clean" environments, contaminants can enter the system during workpiece loading and unloading, and the components within the chamber themselves can outgasse contaminants. For this reason, contamination levels may be continuously monitored to identify conditions that could increase the likelihood of defects in workpieces or reduce inspection accuracy.

[0008] A residual gas analyzer (RGA) can be used to measure in-situ contamination in a vacuum chamber. The RGA collects a residual gas sample and measures the contamination using an electron ionizer, quadrupole mass spectrometer, and detector. However, identifying contaminants present in small portions of such gases from a large and complex chamber can be challenging. Gas column mass spectrometry (GCMS) systems can also be used to improve contaminant detection based on molecular weight and variable interaction forces with the column material. However, GCMS may not be feasible due to the high temperatures required for gas sample collection in an empty chamber, or due to the thermal limitations of components present in the chamber during use.

[0009] To measure contamination in a vacuum chamber, an off-situ process using a sample coupon can also be employed. The sample coupon can be exposed to the vacuum chamber environment, then placed in a separate clean chamber and heated to a high temperature to induce outgassing, allowing for collection into an adsorption tube. The adsorption tube can then be analyzed using an RGA or GCMS system to identify contaminants. However, this is typically a time-consuming process, as the sample coupon remains in the vacuum chamber for an extended period to allow contaminants to transfer to it. Additionally, handling the sample coupon in and out of the chamber carries the risk of cross-contamination, hindering accurate measurements. This risk is increased when the vacuum chamber is located far from the measurement system and maintaining the sample coupon's cleanliness during transport is difficult. [Prior art documents] [Patent Documents]

[0010] [Patent Document 1] Japanese Patent Publication No. 2022-080642 [Patent Document 2] U.S. Patent Application Publication No. 2016 / 0273830 [Patent Document 3] Japanese Patent Application Publication No. 08-188495 [Overview of the project] [Problems that the invention aims to solve]

[0011] Therefore, an improved method for measuring contamination within a vacuum chamber is needed. [Means for solving the problem]

[0012] One embodiment of the present disclosure provides a system. The system may comprise a primary vacuum chamber, a secondary vacuum chamber connected to the primary vacuum chamber via a gate valve, the gate valve being operable between an open position in which the secondary vacuum chamber is in fluid communication with the primary vacuum chamber and a closed position in which the secondary vacuum chamber is sealed from the primary vacuum chamber, a heat exchanger, a gas source, and a sample container. The heat exchanger may be configured to cool the secondary vacuum chamber to adsorb contaminants from the primary vacuum chamber into the secondary vacuum chamber when the gate valve is in the open position. The gas source may be configured to inject a carrier gas into the secondary vacuum chamber when the gate valve is in the closed position. The heat exchanger may be further configured to heat the carrier gas in the secondary vacuum chamber to desorb contaminants and combine them with the carrier gas to form a gas sample. The sample container may be configured to collect a gas sample from the secondary vacuum chamber.

[0013] In some embodiments, the system may further include a mass spectrometer configured to process a gas sample in a sample container and identify contaminants in the gas sample.

[0014] In some embodiments, the carrier gas may include an inert gas.

[0015] In some embodiments, a gas inlet and a gas outlet may be defined in the secondary vacuum chamber. A gas source may be in fluid communication with the gas inlet for injecting a carrier gas into the secondary vacuum chamber, and a sample container may be in fluid communication with the gas outlet for collecting a gas sample from the secondary vacuum chamber.

[0016] In some embodiments, the gas source may be configured to inject a carrier gas into the secondary vacuum chamber by the operation of an inlet valve located between the gas source and the gas inlet.

[0017] In some embodiments, the sample container may be configured to collect a gaseous sample from a secondary vacuum chamber by the operation of an outlet valve located between the sample container and the gas outlet.

[0018] In some embodiments, the heat exchanger may be configured to circulate a cooling fluid from a cooling fluid source for cooling the secondary vacuum chamber, and to circulate a heating fluid from a heating fluid source for heating the secondary vacuum chamber.

[0019] In some embodiments, the cooling fluid may include liquid nitrogen.

[0020] In some embodiments, a cooling channel and a heating channel may be defined in the heat exchanger. The cooling channel can be in fluid communication with the cooling fluid source so as to circulate the cooling fluid, and the heating channel can be in fluid communication with the heating fluid source so as to circulate the heating fluid.

[0021] In some embodiments, a common fluid channel connected to a switching valve may be defined in the heat exchanger. The switching valve may be operable between a cooling position where the common fluid channel is in fluid communication with the cooling fluid source to circulate the cooling fluid, and a heating position where the common fluid channel is in fluid communication with the heating fluid source to circulate the heating fluid.

[0022] In some embodiments, the heat exchanger may comprise a coiled tube wrapped around the outer surface of the secondary vacuum chamber.

[0023] In some embodiments, a coiled groove may be defined on the outer surface of the secondary vacuum chamber, and the coiled tube of the heat exchanger may be disposed in the coiled groove.

[0024] In some embodiments, the system may further comprise a vacuum pump in fluid communication with the primary vacuum chamber. The vacuum pump may be configured to generate a vacuum pressure in the primary vacuum chamber and the secondary vacuum chamber when the gate valve is in the open position.

[0025] In some embodiments, the system may further comprise a semiconductor fabrication tool, a metrology tool, or an inspection tool disposed within the primary vacuum chamber.

[0026] In some embodiments, the primary vacuum chamber can be defined in the housing, and the secondary vacuum chamber can be defined in a full nipple fitting connected to the housing via a gate valve.

[0027] In some embodiments, the system may further include a processor that electronically communicates with the gate valve to control the operation of the gate valve between an open position and a closed position.

[0028] Another embodiment of the present disclosure provides a method, which may include: generating a vacuum pressure in a primary vacuum chamber and a secondary vacuum chamber using a vacuum pump, the secondary vacuum chamber being connected to the primary vacuum chamber via a gate valve, and the secondary vacuum chamber being in fluid communication with the primary vacuum chamber when the gate valve is in the open position; cooling the secondary vacuum chamber using a heat exchanger to adsorb contaminants from the primary vacuum chamber into the secondary vacuum chamber; closing the gate valve to seal the secondary vacuum chamber away from the primary vacuum chamber; injecting a carrier gas into the secondary vacuum chamber using a gas source; heating the secondary vacuum chamber using a heat exchanger to desorb contaminants and combine them with the carrier gas to form a gas sample; and recovering the gas sample from the secondary vacuum chamber into a sample container.

[0029] In some embodiments, the method may further include processing the gaseous sample from the sample container using a mass spectrometer to identify contaminants.

[0030] In some embodiments, cooling a secondary vacuum chamber using a heat exchanger may involve circulating a cooling fluid from a cooling fluid source through cooling channels in the heat exchanger.

[0031] In some embodiments, heating a secondary vacuum chamber using a heat exchanger may involve circulating a heating fluid from a heating fluid source through heating channels in the heat exchanger.

[0032] In some embodiments, cooling a secondary vacuum chamber using a heat exchanger may include moving a switching valve to a cooling position where the cooling fluid source is in fluid communication with a common fluid channel of the heat exchanger, and circulating the cooling fluid from the cooling fluid source through the common fluid channel of the heat exchanger.

[0033] In some embodiments, heating a secondary vacuum chamber using a heat exchanger may include moving a switching valve to a heating position where the heating fluid source is in fluid communication with a common fluid channel of the heat exchanger, and circulating the heating fluid from the heating fluid source through the common fluid channel of the heat exchanger.

[0034] For a more complete understanding of the nature and purpose of this disclosure, please refer to the following detailed description, which should be interpreted in conjunction with the attached drawings. [Brief explanation of the drawing]

[0035] [Figure 1A] This is a diagram of a system according to an embodiment of the present disclosure, with the gate valve in the open position. [Figure 1B] This is a diagram of the system in Figure 1A with the gate valve in the closed position. [Figure 2A] This is a partial cross-sectional view of the junction between the secondary vacuum chamber and the heat exchanger of a system according to an embodiment of the present disclosure. [Figure 2B] Figure 2A is a fluid circuit diagram of the heat exchanger. [Figure 3A] This is a partial cross-sectional view of the junction between the secondary vacuum chamber and the heat exchanger of a system according to another embodiment of the present disclosure. [Figure 3B] Figure 3A is a fluid circuit diagram of the heat exchanger with the switching valve in the cooling position. [Figure 3C] Figure 3A is a fluid circuit diagram of the heat exchanger with the switching valve in the heating position. [Figure 4] This is a flowchart of the method according to the embodiments of this disclosure. [Figure 5] This is a flowchart of a method according to another embodiment of the present disclosure. [Figure 6A]This is a flowchart of a method according to another embodiment of the present disclosure. [Figure 6B] This is a flowchart of a method according to another embodiment of the present disclosure. [Modes for carrying out the invention]

[0036] While the claimed subject matter is described in terms of specific embodiments, other embodiments, including those that do not provide all of the benefits and features described herein, are also within the scope of this disclosure. Various structural, logical, process step, and electronic modifications can be made without departing from the scope of this disclosure. Accordingly, the scope of this disclosure is defined solely by reference to the accompanying claims.

[0037] One embodiment of this disclosure provides a system 100, which may be a semiconductor manufacturing, etching-deposition, inspection, or measurement system configured to process a workpiece. The workpiece may be, for example, a photomask (reticle), a semiconductor wafer, a substrate, a printed circuit board (PCB), an integrated circuit (IC), a flat panel display (FPD), or other types of workpieces.

[0038] System 100 may include a primary vacuum chamber 110, as shown in Figures 1A and 1B. The primary vacuum chamber 110 can be defined in the housing 111 and may have any large size and shape, not limited herein. An instrument 101 may be disposed within the primary vacuum chamber 110. The instrument 101 may be a measuring tool, inspection tool, fabrication tool, or other type of instrument used to process workpieces in a semiconductor manufacturing, inspection, or measurement system.

[0039] The system 100 may further include a secondary vacuum chamber 120. The secondary vacuum chamber 120 may be connected to the primary vacuum chamber 110 via a gate valve 115. In some embodiments, the secondary vacuum chamber 120 may be defined by a full nipple fitting 121 connected to the housing 111 via the gate valve 115. The full nipple fitting 121 may be connected to the housing 111 with an existing outlet port or with an outlet port manufactured to connect to the full nipple fitting 121. The full nipple fitting 121 may have a flange at one end for connection to the housing 111. For example, the flange may be secured to the housing 111 by one or more fasteners, and the gate valve 115 may be sandwiched between the flange and the housing 111. The other end of the full nipple fitting 121 may have another flange, which, when closed, can define a secondary vacuum chamber between the two flanges. In some embodiments, the full nipple fitting 121 may have a diameter of 1.33 inches to 10 inches.

[0040] The gate valve 115 may be operable between an open position (shown in Figure 1A) and a closed position (shown in Figure 1B). For example, in the open position, the gate 116 of the gate valve 115 may be positioned so that the secondary vacuum chamber 120 is in fluid communication with the primary vacuum chamber 110. In the closed position, the gate 116 of the gate valve 115 may be positioned so that the secondary vacuum chamber 120 is sealed from the primary vacuum chamber 110. The gate valve 115 may comprise any suitable valve configured to be operable between the open and closed positions to selectively open and close the fluid communication between the primary vacuum chamber 110 and the secondary vacuum chamber 120, and is not limited to a specific valve with a gate, or the exemplary structure shown in Figure 1A or Figure 1B. For example, the gate valve 115 may be a pendulum valve, a butterfly valve, or any other type of vacuum isolation valve.

[0041] System 100 may further include a vacuum pump 105. The vacuum pump 105 may be in fluid communication with the primary vacuum chamber 110. When the gate valve 115 is in the open position, the vacuum pump 105 may further be in fluid communication with the secondary vacuum chamber 120 via the primary vacuum chamber 110. The vacuum pump 105 may be configured to generate vacuum pressure in the primary vacuum chamber 110 and the secondary vacuum chamber 120 when the gate valve 115 is in the open position. The vacuum pressure may be in the range of high vacuum to ultra-high vacuum. For example, this pressure may be several tens of millitorres (1e -3 Thor) to several tens of nanotons (1e -8 It may be within the range of Torr.

[0042] The system 100 may further include a heat exchanger 130. The heat exchanger 130 may be configured to cool the secondary vacuum chamber 120. For example, the heat exchanger 130 may include a coiled tube wound around the outer surface 122 of the secondary vacuum chamber 120. In some embodiments, the coiled tube may be made of copper. In some embodiments (as shown in Figures 2A and 3A), a coiled groove 123 can be defined on the outer surface 122 of the secondary vacuum chamber 120, and the coiled tube of the heat exchanger 130 can be placed in the coiled groove 123. Such a configuration can increase the surface contact between the heat exchanger 130 and the secondary vacuum chamber 120, thereby improving the cooling effect. When the gate valve 115 is in the open position (as shown in Figure 1A) and the heat exchanger 130 is cooling the secondary vacuum chamber 120, contaminants 102 can be adsorbed from the primary vacuum chamber 110 into the secondary vacuum chamber 120. For example, the inner surface 124 of the secondary vacuum chamber 120 can function as a cold trap so that contaminants 102 are attracted to and embedded in the inner surface 124 of the secondary vacuum chamber 120. The capture efficiency of the inner surface 124 of the secondary vacuum chamber 120 can be proportional to the temperature. For example, the temperature can range from 0°C to the liquid nitrogen temperature (i.e., below -196°C). The contaminants 102 can be any volatile organic compounds (VOCs) or volatile inorganic compounds present in the residual gas of the primary vacuum chamber 110 or outgassed from components within the primary vacuum chamber 110. After being in the open position for a fixed time, the gate valve 115 can then be moved to the closed position (as shown in Figure 1B) to seal the contaminants 102 inside the secondary vacuum chamber 120. The length of time can depend on the temperature. For example, the gate valve 115 may remain open for one night to several days at a temperature of 0°C, or it may remain open for only a few hours at liquid nitrogen temperature to obtain a sufficient cold trap effect.

[0043] The system 100 may further include a gas source 140. The gas source 140 may be configured to inject a carrier gas into the secondary vacuum chamber 120. For example, when the gate valve 115 is in the closed position, the gas source 140 can inject a carrier gas into the secondary vacuum chamber 120. The carrier gas may be an inert gas such as nitrogen (N2), argon, helium, clean dry air (CDA), or other types of gas, and is not particularly limited herein. A gas inlet 141 may be defined in the secondary vacuum chamber 120, and the gas source 140 may be in fluid communication with the gas inlet 141 to inject the carrier gas into the secondary vacuum chamber 120. In some embodiments, the carrier gas may be pressurized in the gas source 140 so that the carrier gas is injected into the secondary vacuum chamber 120 via the gas inlet 141 by opening the inlet valve 142. In some embodiments, the gas inlet 141 may be located at the closed end of a full nipple fitting 121 on the side away from the housing 111. The gas source 140 may further include a mass flow controller and / or purifier for controlling the flow rate and purity of the carrier gas injected into the secondary vacuum chamber 120.

[0044] The heat exchanger 130 may be further configured to heat the secondary vacuum chamber 120. For example, the heat exchanger 130 may be configured to heat the carrier gas in the secondary vacuum chamber 120 to desorb contaminants 102 embedded on the inner surface 124 of the secondary vacuum chamber 120, which then combine with the carrier gas to form a gas sample 103. In some embodiments, the heat exchanger 130 may be configured to heat the secondary vacuum chamber 120 to a temperature of 50°C to 300°C or higher. The rate of desorption may be proportional to the temperature. For example, the higher the temperature, the faster the desorption of contaminants 102. The temperature may be limited by the melting point of the substances present in the secondary vacuum chamber 120. In some embodiments, the heat exchanger 130 may heat the secondary vacuum chamber 120 to a temperature of 300°C as a pre-cleaning step to desorb any existing contaminants from the inner surface 124 of the vacuum chamber 120 before collecting contaminants 102 from the primary vacuum chamber 110. The heat exchanger 130 can heat the secondary vacuum chamber 120 for a predetermined period of time after reaching the target temperature. The length of this period may depend on the temperature. For example, the heat exchanger 130 may heat the secondary vacuum chamber 120 at a relatively low temperature for several days, or it may heat the secondary vacuum chamber 120 for only a few hours to ensure sufficient desorption.

[0045] The system 100 may further include a sample container 145. The sample container 145 may be an adsorption tube or other gas container. The sample container 145 may be configured to collect a gas sample 103 from the secondary vacuum chamber 120. A gas outlet 143 may be defined in the secondary vacuum chamber 120, and the sample container 145 may be in fluid communication with the gas outlet 143 to collect the gas sample 103 from the secondary vacuum chamber 120. In some embodiments, the gas outlet 143 may be located at the closed end of a full nipple fitting 121 on the side away from the housing 111. In some embodiments, an outlet valve 144 may be opened to release the gas sample 103 from the secondary vacuum chamber 120 into the sample container 145.

[0046] System 100 may further include a mass spectrometer 150. The mass spectrometer 150 may be a standalone system or part of a GCMS instrument. The mass spectrometer 150 may be configured to receive a sample container 145 and identify contaminants 102 in a gas sample 103. In particular, the mass spectrometer 150 may be configured to perform chemical species identification or molecular identification of contaminants 102 in the gas sample 103 based on the temperature rise of the gas sample 103 in the secondary vacuum chamber 120 caused by the heat exchanger 130. The concentration of contaminants 102 in the high-temperature sample container 145 may improve detection and identification using the mass spectrometer 150. The mass spectrometer 150 may be isolated from the secondary vacuum chamber 120 and other elements of System 100. For example, the sample container 145 may be transported to the mass spectrometer 150 by automated means (e.g., a robotic arm) or manual means.

[0047] System 100 may further comprise a processor 160. The processor 160 may include a microprocessor, microcontroller, or other device. The processor 160 may be coupled to components of System 100 in any preferred manner (e.g., via one or more transmission media, which may include wired and / or wireless transmission media) so that the processor 160 can receive outputs. The processor 160 may be configured to perform several functions using its outputs. A test tool may receive instructions or other information from the processor 160. The processor 160 may optionally communicate electronically with another test tool, measurement tool, repair tool, or review tool (not shown) to receive additional information or send instructions.

[0048] The processor 160 may be part of a variety of systems, including personal computer systems, image computers, mainframe computer systems, workstations, network equipment, internet equipment, or other devices. The subsystem or system may also include any suitable processor known in the art, such as a parallel processor. In addition, the subsystem or system may include a platform with high-speed processing capabilities and software, either as a standalone or networked tool.

[0049] The processor 160 may be located within the system 100 or another device, or it may be part of the system 100. In one example, the processor 160 may be part of a standalone control unit or it may reside within a centralized quality control unit. Multiple processors 160 may be used to define multiple subsystems of the system 100.

[0050] The processor 160 can actually be implemented by any combination of hardware, software, and firmware. Furthermore, its functions as described herein may be performed by a single unit or divided among different components, each of which may be executed sequentially by any combination of hardware, software, and firmware. Program code or instructions for the processor 160 to perform various methods and functions may be stored in a readable storage medium such as memory.

[0051] If the system 100 includes two or more subsystems, various processors 160 may be coupled to each other so that images, data, information, instructions, etc., can be sent between those subsystems. For example, one subsystem may be coupled to an additional subsystem by any suitable transmission medium, which may include any suitable wired and / or wireless transmission medium known in the art. Alternatively, two or more such subsystems may be effectively coupled by a shared computer-readable storage medium (not shown).

[0052] The processor 160 may be configured to perform several functions using the outputs of the system 100 or other outputs. For example, the processor 160 may be configured to send an output to an electronic data storage unit or another storage medium. The processor 160 may be further configured as described herein.

[0053] The processor 160 may be configured according to any of the embodiments described herein. The processor 160 may also be configured to perform other functions or additional steps using the output of system 100 or images or data from other sources.

[0054] The processor 160 may be communicatively coupled to any of the various components or subsystems of System 100 in any manner known in the art. Furthermore, the processor 160 may be configured to receive and / or acquire data or information from other systems (e.g., inspection results from an inspection system such as a review tool, a remote database containing design data) via a transmission medium which may include wired and / or wireless portions. In this way, the transmission medium may serve as a data link between the processor 160 and other subsystems of System 100 or systems outside of System 100. Various steps, functions, and / or operations of System 100 and methods disclosed herein are performed by one or more of the following: electronic circuits, logic gates, multiplexers, programmable logic devices, ASICs, analog or digital controls / switches, microcontrollers, or computing systems. Program instructions for performing methods such as those described herein may be transmitted via or stored on a carrier medium. The carrier medium may include storage media such as read-only memory, random-access memory, magnetic or optical disks, non-volatile memory, solid-state memory, magnetic tape, and similar devices. The carrier medium may also include transmission media such as wires, cables, or wireless transmission links. For example, the various steps described throughout this disclosure may be performed by a single processor 160 (or computer subsystem), or alternatively, by multiple processors 160 (or multiple computer subsystems). Furthermore, the various subsystems of system 100 may include one or more computing systems or logical systems. Thus, the above description should be interpreted as illustrative only and not as an limitation to this disclosure.

[0055] The processor 160 can communicate electronically with the vacuum pump 105. For example, the processor 160 may be configured to control the operation of the vacuum pump 105 to generate vacuum pressure in the primary vacuum chamber 110 and the secondary vacuum chamber 120 when the gate valve 115 is in the open position.

[0056] The processor 160 can communicate electronically with the gate valve 115. For example, the processor 160 may be configured to control the operation of the gate valve 115 between the open and closed positions.

[0057] The processor 160 can communicate electronically with the heat exchanger 130. For example, the processor 160 may be configured to control the operation of the heat exchanger 130 to cool and heat the secondary vacuum chamber 120.

[0058] The processor 160 can communicate electronically with the gas source 140. For example, the processor 160 may be configured to control the operation of the inlet valve 142 so that a carrier gas is injected from the gas source 140 into the secondary vacuum chamber 120 via the gas inlet 141.

[0059] The processor 160 can communicate electronically with the mass spectrometer 150. For example, the processor 160 may be configured to control the operation of the outlet valve 144 so that the gas sample 103 is collected from the secondary vacuum chamber 120 through the gas outlet 143 into the sample container 145, or the processor 160 may be configured to control the mass spectrometer so that the gas sample 103 in the sample container 145 is processed to identify contaminants 102 in the gas sample 103.

[0060] In some embodiments, separate fluid channels can be defined in the heat exchanger 130 to cool and heat the secondary vacuum chamber 120. For example, as shown in Figures 2A and 2B, a cooling channel 135a and a heating channel 135b may be defined in the heat exchanger 130. The cooling channel 135a can be in fluid communication with a cooling fluid source 131, and the heating channel 135b can be in fluid communication with a heating fluid source 132. The heat exchanger 130 may be configured to cool the secondary vacuum chamber 120 by circulating a cooling fluid from the cooling fluid source 131 through the cooling channel 135a, and to adsorb contaminants 102 from the primary vacuum chamber 110 into the secondary vacuum chamber 120. In some embodiments, the cooling fluid may include, for example, liquid nitrogen, chilled water, or an ethylene glycol solution. The heat exchanger 130 may be further configured to heat the secondary vacuum chamber 120 by circulating a heating fluid from a heating fluid source 132 through a heating channel 135b, desorbing contaminants 102 and combining them with a carrier gas to form a gas sample 103. In some embodiments, the heating fluid may include, for example, hot water, steam, or other fluids. As shown in Figure 2A, the cooling channels 135a and heating channels 135b of the heat exchanger 130 may be arranged alternately along the outer surface 122 of the secondary vacuum chamber 120. As shown in Figure 2B, the heat exchanger 130 may further comprise a cooling fluid pump 133a and a cooling fluid valve 134a configured to circulate a cooling fluid from a cooling fluid source 131 through a cooling channel 135a, and the heat exchanger 130 may further comprise a heating fluid pump 133b and a heating fluid valve 134b configured to circulate a heating fluid from a heating fluid source 132 through a heating channel 135b. In some embodiments, the processor 160 may be configured to control the operation of the cooling fluid pump 133a and / or the cooling fluid valve 134a in order to control the heat exchanger 130 to cool the secondary vacuum chamber 120, and the processor 160 may be further configured to control the operation of the heating fluid pump 133b and / or the heating fluid valve 134b in order to control the heat exchanger 130 to heat the secondary vacuum chamber 120.In some embodiments, the heat exchanger 130 may include an electric heater configured to heat the secondary vacuum chamber 120, acting similarly to the circulation of a heated fluid. The electric heater may be wrapped around a full nipple fitting 121. The electric heater can generate heat to desorb contaminants 102 into the gas sample 103, using heat tape or resistance heating.

[0061] In some embodiments, a single fluid channel can be defined in the heat exchanger 130 for cooling and heating the secondary vacuum chamber 120. For example, a common fluid channel 135c may be defined in the heat exchanger 130, as shown in Figures 3A, 3B, and 3C. The common fluid channel 135c can be in fluid communication with a cooling fluid source 131 and a heating fluid source 132, subject to the operation of a switching valve 136 that is operable between a cooling position and a heating position. For example, in the cooling position (shown in Figure 3B), the common fluid channel 135c can be in fluid communication with the cooling fluid source 131 to circulate a cooling fluid and cool the secondary vacuum chamber 120 in order to adsorb contaminants 102 from the primary vacuum chamber 110 into the secondary vacuum chamber 120. In the heating position (shown in Figure 3C), the common fluid channel 135c can circulate the heating fluid to heat the secondary vacuum chamber 120, in fluid communication with the heating fluid source 132 to desorb contaminants 102 and combine them with the carrier gas to form a gas sample 103. The switching valve 136 may comprise any suitable valve configured to operate between the cooling position and the heating position to selectively open and close the fluid communication between the common fluid channel 135c and either the cooling fluid 131 or the heating fluid source 132. As shown in Figure 3A, the common fluid channel 135c may be wrapped around the outer surface 122 of the secondary vacuum chamber 120. As shown in Figures 3B and 3C, the heat exchanger 130 may further comprise a common fluid pump 133c and a common fluid valve 134c configured to circulate cooling fluid from the cooling fluid source 131 and heating fluid from the heating fluid source 132, depending on the position of the switching valve 136. In some embodiments, the processor 160 may be configured to control the operation of the switching valve 136 between a cooling position and a heating position.The processor 160 may be further configured to control a common fluid pump 133c and / or a common fluid valve 134c to control the heat exchanger 130 to cool the secondary vacuum chamber 120 when the switching valve 136 is in the cooling position, and the processor 160 may be further configured to control the operation of the common fluid pump 133c and / or a common fluid valve 134c to control the heat exchanger 130 to heat the secondary vacuum chamber 120 when the switching valve 136 is in the heating position.

[0062] In some embodiments, the system 100 may be a dedicated contamination testing system. For example, the system may be configured to process a particular workpiece under test to determine the contaminant profile of the workpiece if the identified contaminant 102 in the gas sample 103 is a contaminant outgassed from the workpiece.

[0063] In system 100, contaminants 102 from the primary vacuum chamber 110 can be collected in the secondary vacuum chamber 120 in an efficient manner with reduced collection time by cold trapping with a heat exchanger 130. The heat exchanger 130 may also be capable of heating the secondary vacuum chamber 120 without heating the primary vacuum chamber 110. Heating the primary vacuum chamber 110 could adversely affect machining tolerances or critical assemblies of components within the primary vacuum chamber 110 that have low operating temperature limits. The higher the temperature of the gas sample 103, the higher the resolution of in-situ contamination measurements by the mass spectrometer 150, which allows for identification of contaminants 102 on a species-based or molecular-based basis. System 100 also includes 1 × 10⁻⁶ -14A primary vacuum chamber 110 of any size, geometry, or occupancy state (i.e., empty or containing components) with a partial pressure of Toll or lower can also be applied. As a result, the system 100 can reduce the number of defects caused by contamination and improve inspection quality. Because the primary vacuum chamber 110 can be kept sealed during testing, the system 100 can also suppress overall contamination. This helps to suppress transmission loss and maintain tool uptime, resulting in reduced ownership and maintenance costs.

[0064] Another embodiment of the present disclosure provides Method 200. As shown in Figure 4, Method 200 may include the following steps:

[0065] In step 210, a vacuum pump is used to create vacuum pressure in the primary and secondary vacuum chambers. The primary vacuum chamber can be defined as a housing having any large size and shape, not limited herein. For example, equipment such as measuring tools, inspection tools, fabrication tools, or other types of instruments used in semiconductor manufacturing, inspection, or measurement systems can be placed in the primary vacuum chamber. The secondary vacuum chamber can be defined as a full nipple fitting connected to the housing, and a gate valve can be sandwiched between the full nipple fitting and the housing. The vacuum pump can be in fluid communication with the primary vacuum chamber, and when the gate valve is in the open position, the vacuum pump can further be in fluid communication with the secondary vacuum chamber. The vacuum pressure can be in the range of high vacuum to ultra-high vacuum. For example, this pressure can be several tens of millitorres (1e -3 Thor) to several tens of nanotons (1e -8 It may be within the range of Torr.

[0066] In step 220, the secondary vacuum chamber is cooled using a heat exchanger to adsorb contaminants from the primary vacuum chamber into the secondary vacuum chamber. For example, the heat exchanger may be configured to cool the outer surface of the secondary vacuum chamber so that the inner surface of the secondary vacuum chamber acts as a cold trap to attract contaminants from the primary vacuum chamber. The heat exchanger can cool the secondary vacuum chamber for a fixed period of time to collect contaminants. For example, the cooling temperature may range from 0°C to the temperature of liquid nitrogen (i.e., below -196°C).

[0067] In step 230, the gate valve is closed to seal the secondary vacuum chamber from the primary vacuum chamber. For example, the gate valve may be operable between an open position and a closed position. In the open position, the gate of the gate valve may be positioned so that the secondary vacuum chamber is in fluid communication with the primary vacuum chamber. In the closed position, the gate of the gate valve may be positioned so that the secondary vacuum chamber is sealed from the primary vacuum chamber. The gate valve may comprise any suitable valve configured to be operable between an open position and a closed position to selectively open and close the fluid communication between the primary vacuum chamber and the secondary vacuum chamber. For example, the gate valve 115 may be a pendulum valve, a butterfly valve, or any other type of vacuum isolation valve. By closing the gate valve, contaminants adsorbed from the primary vacuum chamber can be trapped in the secondary vacuum chamber.

[0068] In step 240, a carrier gas is injected into the secondary vacuum chamber using a gas source. For example, the carrier gas can be injected from the gas source into the gas inlet of the secondary vacuum chamber. The carrier gas may be pressurized in the gas source so that it is injected into the secondary vacuum chamber by opening the inlet valve. In some embodiments, the carrier gas may be an inert gas such as nitrogen (N2), argon, helium, clean dry air (CDA), or other types of gas, and is not particularly limited herein.

[0069] In step 250, a heat exchanger is used to heat the secondary vacuum chamber to desorb contaminants, which are then combined with the carrier gas to form a gas sample. For example, the heat exchanger can be configured to heat the outer surface of the secondary vacuum chamber, resulting in the desorption of contaminants from the inner surface of the secondary vacuum chamber, which are then combined with the carrier gas to form a gas sample. The heat exchanger can heat the secondary vacuum chamber for a predetermined time after reaching the target temperature. For example, the heat exchanger can be configured to heat the secondary vacuum chamber to a temperature of 50°C to 300°C or higher. Such high temperatures can improve the ability of the mass spectrometer to identify chemical species and molecules in the contaminants.

[0070] In step 260, the gas sample is collected from the secondary vacuum chamber into the sample container. For example, the gas sample may be collected into the sample container from the gas outlet of the secondary vacuum chamber by opening the outlet valve.

[0071] In step 270, the gas sample from the sample container is processed using a mass spectrometer to identify contaminants. For example, the mass spectrometer may be configured to perform chemical species identification or molecular identification of contaminants in the gas sample based on the temperature rise of the gas sample in the secondary vacuum chamber caused by a heat exchanger. The mass spectrometer may be a standalone system or part of a GCMS instrument.

[0072] In some embodiments, the heat exchanger can be configured to define separate fluid channels that are configured to cool and heat the secondary vacuum chamber. Accordingly, steps 220 and 250 of method 200 can be replaced by the following steps, as shown in Figure 5.

[0073] In step 221, a cooling fluid is circulated from a cooling fluid source through cooling channels in the heat exchanger to cool the secondary vacuum chamber and adsorb contaminants from the primary vacuum chamber into the secondary vacuum chamber. In some embodiments, the cooling fluid may include liquid nitrogen. The heat exchanger may further include a cooling fluid pump and a cooling fluid valve configured to circulate the cooling fluid from the cooling fluid source through cooling channels.

[0074] In step 251, a heating fluid is circulated from a heating fluid source through heating channels of a heat exchanger to heat the secondary vacuum chamber and desorb contaminants, which are then combined with the carrier gas to form a gas sample. In some embodiments, the heating fluid may include hot water. The heat exchanger may further include a heating fluid pump and a heating fluid valve configured to circulate the heating fluid from the heating fluid source through heating channels.

[0075] In some embodiments, a single fluid channel can be defined in the heat exchanger, configured to cool and heat a secondary vacuum chamber, and a switching valve can be configured to switch between cooling and heating functions. The switching valve may comprise any suitable valve configured to be operable between a cooling position and a heating position to selectively open and close the fluid communication between the common fluid channel and either a cooling fluid source or a heating fluid source. Accordingly, step 220 of method 200 may include the following steps shown in Figure 6A, and step 250 of method 200 may include the following steps shown in Figure 6B.

[0076] In step 222, the switching valve is moved to a cooling position where the cooling fluid source is in fluid communication with the common fluid channel of the heat exchanger.

[0077] In step 223, a cooling fluid is circulated from a cooling fluid source through a common fluid channel of the heat exchanger to cool the secondary vacuum chamber and adsorb contaminants from the primary vacuum chamber into the secondary vacuum chamber. The heat exchanger may further include a common fluid pump and a common fluid valve configured to circulate the cooling fluid from the cooling fluid source when the switching valve is in the cooling position.

[0078] In step 252, the switching valve is moved to a heating position where the heating fluid source is in fluid communication with the common fluid channel of the heat exchanger.

[0079] In step 253, a heating fluid is circulated from a heating fluid source through a common fluid channel of the heat exchanger to heat the secondary vacuum chamber and desorb contaminants, which are then combined with the carrier gas to form a gas sample. The heat exchanger's common fluid pump and common fluid valve may be further configured to circulate the heating fluid from the heating fluid source when the switching valve is in the heating position.

[0080] In Method 200, contaminants from the primary vacuum chamber can be collected into the secondary vacuum chamber in an efficient manner with reduced collection time by cold trapping with a heat exchanger. The heat exchanger may also be capable of heating the secondary vacuum chamber without heating the primary vacuum chamber. Heating the primary vacuum chamber can adversely affect machining tolerances or critical assemblies of components with low operating temperature limits within the primary vacuum chamber. The higher the temperature of the gas sample, the higher the resolution of in-situ contamination measurements by mass spectrometer, which allows for identification of contaminants on a chemical species basis or molecular basis. The system also includes 1 × 10⁻⁶ -14 A primary vacuum chamber of any size, geometry, or occupancy state (i.e., empty or containing components) with a partial pressure of Toll or lower can also be applied. Consequently, method 200 can reduce the number of defects caused by contamination and improve inspection quality.

[0081] While this disclosure has been described in relation to one or more specific embodiments, it will be understood that other embodiments of this disclosure can be constructed without departing from the scope of this disclosure. Therefore, this disclosure is construed to be limited only by the accompanying claims and their reasonable interpretation.

Claims

1. Primary vacuum chamber and A secondary vacuum chamber connected to the primary vacuum chamber via a gate valve, wherein the gate valve is operable between an open position in which the secondary vacuum chamber is in fluid communication with the primary vacuum chamber and a closed position in which the secondary vacuum chamber is sealed from the primary vacuum chamber, A heat exchanger configured to cool the secondary vacuum chamber in order to adsorb contaminants from the primary vacuum chamber into the secondary vacuum chamber when the gate valve is in the open position, A gas source configured to inject a carrier gas into the secondary vacuum chamber when the gate valve is in the closed position, wherein the heat exchanger is further configured to heat the carrier gas in the secondary vacuum chamber to desorb contaminants and combine them with the carrier gas to form a gas sample, A sample container configured to collect the gas sample from the secondary vacuum chamber, A system characterized by comprising the following features.

2. A system according to claim 1, comprising a mass spectrometer configured to process the gas sample in the sample container and identify the contaminants in the gas sample. A system characterized by further comprising the following features.

3. The system according to claim 1, wherein the carrier gas includes an inert gas.

4. A system according to claim 1, wherein the secondary vacuum chamber has a defined gas inlet and a gas outlet, the gas source is in fluid communication with the gas inlet so that the carrier gas is injected into the secondary vacuum chamber, and the sample container is in fluid communication with the gas outlet so that the gas sample is collected from the secondary vacuum chamber.

5. The system according to claim 4, characterized in that the gas source is configured to inject the carrier gas into the secondary vacuum chamber by the operation of an inlet valve disposed between the gas source and the gas inlet.

6. The system according to claim 4, characterized in that the sample container is configured to collect the gas sample from the secondary vacuum chamber by the operation of an outlet valve disposed between the sample container and the gas outlet.

7. The system according to claim 1, wherein the heat exchanger is configured to circulate a cooling fluid from a cooling fluid source for cooling the secondary vacuum chamber and to circulate a heating fluid from a heating fluid source for heating the secondary vacuum chamber.

8. The system according to claim 7, wherein the cooling fluid includes liquid nitrogen.

9. A system according to claim 7, wherein the heat exchanger has defined cooling channels and heating channels, the cooling channels are in fluid communication with a cooling fluid source to circulate the cooling fluid, and the heating channels are in fluid communication with a heating fluid source to circulate the heating fluid.

10. The system according to claim 7, wherein the heat exchanger has a defined common fluid channel connected to a switching valve, and the switching valve is operable between a cooling position in which the common fluid channel is in fluid communication with the cooling fluid source so as to circulate the cooling fluid, and a heating position in which the common fluid channel is in fluid communication with the heating fluid source so as to circulate the heating fluid.

11. The system according to claim 1, wherein the heat exchanger comprises a coil tube wound around the outer surface of the secondary vacuum chamber.

12. A system according to claim 11, characterized in that a coil-shaped groove is defined on the outer surface of the secondary vacuum chamber, and the coil tube of the heat exchanger is disposed within the coil-shaped groove.

13. The system according to claim 1, The system further comprises a vacuum pump that is in fluid communication with the primary vacuum chamber, and is configured to generate vacuum pressure in the primary vacuum chamber and the secondary vacuum chamber when the gate valve is in the open position.

14. The system according to claim 1, The system is further characterized by comprising semiconductor fabrication tools, measurement tools, or inspection tools arranged within the primary vacuum chamber.

15. A system according to claim 1, characterized in that the primary vacuum chamber is defined in a housing, and the secondary vacuum chamber is defined in a full nipple fitting connected to the housing via a gate valve.

16. The system according to claim 1, The system further comprises a processor that electronically communicates with the gate valve in order to control the operation of the gate valve between the open position and the closed position.

17. The method involves generating vacuum pressure in a primary vacuum chamber and a secondary vacuum chamber using a vacuum pump, wherein the secondary vacuum chamber is connected to the primary vacuum chamber via a gate valve, and the secondary vacuum chamber is in fluid communication with the primary vacuum chamber when the gate valve is in the open position, In order to adsorb contaminants from the primary vacuum chamber into the secondary vacuum chamber, the secondary vacuum chamber is cooled using a heat exchanger, To seal the secondary vacuum chamber away from the primary vacuum chamber, the gate valve is closed. Injecting a carrier gas into the secondary vacuum chamber using a gas source, The secondary vacuum chamber is heated using the heat exchanger to desorb the contaminants, and these are then combined with the carrier gas to form a gas sample. The gas sample is collected from the secondary vacuum chamber into the sample container, A method characterized by including the following.

18. The method according to claim 17, A method further comprising processing the gas sample from the sample container using a mass spectrometer in order to identify the contaminant.

19. The method according to claim 17, Cooling the secondary vacuum chamber using the heat exchanger means This includes circulating a cooling fluid from a cooling fluid source through the cooling channels of the heat exchanger, Heating the secondary vacuum chamber using the heat exchanger is A method characterized by including circulating a heating fluid from a heating fluid source through a heating channel of a heat exchanger.

20. The method according to claim 17, Cooling the secondary vacuum chamber using the heat exchanger means The switching valve is moved to a cooling position where the cooling fluid source is in fluid communication with the common fluid channel of the heat exchanger, This includes circulating the cooling fluid from the cooling fluid source through the common fluid channel of the heat exchanger, Heating the secondary vacuum chamber using the heat exchanger is The switching valve moves to a heating position where the heating fluid source is in fluid communication with the common fluid channel of the heat exchanger, A method characterized by circulating a heating fluid from the heating fluid source through the common fluid channel of the heat exchanger.

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