Method for performing qualification actions in exposure equipment

Abstract

A method for performing a system qualification action relating to an exposure apparatus or its components is disclosed. The method includes obtaining test timing data and reference timing test data for one or more test timing parameters, each test timing parameter describing a system action period, and each system action period describing a system action period of the exposure apparatus or its components; and qualifying the exposure apparatus or its components in terms of one or more quality performance parameters based on a comparison of the test timing data and the reference timing test data.

Description

Technical Field

[0001] (Cross - reference to related applications)

[0001] This application claims priority to European Application No. 23172341.2 filed on May 9, 2023, the entire content of which is incorporated herein by reference.

[0002]

[0002] The present invention relates to a method and apparatus that can be used in the manufacture of devices by, for example, lithography technology, and also to a method for manufacturing a device using lithography technology.

Background Art

[0003]

[0003] A lithography apparatus is a machine that applies a desired pattern onto a substrate, usually onto a target portion of the substrate. A lithography apparatus can be used, for example, in the manufacture of integrated circuits (ICs). In such a case, a patterning device, also alternatively called a mask or a reticle, can be used to generate the circuit pattern to be formed on individual layers of the IC. This pattern can be transferred onto a target portion (e.g., including a part of one or several dies) on a substrate (e.g., a silicon wafer). The transfer of the pattern is usually performed by imaging onto a layer of radiation - sensitive material (resist) provided on the substrate. Generally, a single substrate includes a network of adjacent target portions to which patterns are sequentially applied. These target portions are generally referred to as “fields”.

[0004]

[0004] In the manufacture of composite devices, many lithography patterning steps are typically performed, thereby layering functional features onto a substrate. Therefore, a crucial aspect of the performance of a lithography apparatus is its ability to correctly and accurately position the applied pattern relative to features formed in previous layers (by the same apparatus or a different lithography apparatus). For this purpose, the substrate is provided with one or more sets of alignment marks. Each mark is structured in such a way that its position can be measured at a later point in time using a position sensor, usually an optical position sensor. The lithography apparatus is equipped with one or more alignment sensors that can accurately measure the position of the marks on the substrate. Different types of marks and different types of alignment sensors are known between different manufacturers and between different products from the same manufacturer.

[0005]

[0005] In other applications, metronomes are used to measure exposure structures on substrates (in and / or after etching). One of the fast, minimally invasive forms of specialized inspection tools is a scattermeter, which irradiates a target on the surface of a substrate with a radiation beam and measures the properties of the scattered or reflected beam. For example, angle-resolved scattermeters of the type described in US2006033921A1 and US2010201963A1 are known. In addition to measurements by reconstruction of characteristic shapes, diffraction-based overlays can also be measured using such devices, as described in US2006066855A1. Diffraction-based overlay metronomes enable overlay measurements on smaller targets by using dark-field imaging of diffraction order. Examples of dark-field imaging metronomes are found in WO2009 / 078708 and WO2009 / 106279, which are incorporated herein by reference in their entirety. Further developments of this technology are described in US20110027704A, US20110043791A, US2011102753A1, US20120044470A, US20120123581A, US20130258310A, US20130271740A, and WO2013178422A1. These targets may be smaller than the illumination spot and may be surrounded by the product structure on the wafer. By using composite grating targets, multiple gratings can be measured in a single image. The entire disclosures of all these applications are also incorporated herein by reference.

[0006]

[0006] When a tool is first installed or delivered, or when a tool is serviced (for example, when maintenance work such as component replacement or hardware or software updates is performed), the tool's performance needs to be periodically qualified or evaluated. Performance is typically measured by five main performance metrics: focus, imaging, defects, overlay, and productivity. Properly qualifying a tool in terms of all these performance metrics takes considerable time.

[0007]

[0007] It is desirable to reduce the current time required for such qualification assessment actions. [Overview of the project]

[0008]

[0008] In a first aspect of the present invention, the present invention provides a method for performing a system qualification action relating to an exposure apparatus or its components, comprising: obtaining test timing data relating to one or more test timing parameters, each test timing parameter describing a respective system action period, and each system action period describing a respective system action period of the exposure apparatus or its components; obtaining reference timing test data including reference values ​​for one or more system action periods; and qualifying the exposure apparatus or its components in terms of one or more quality performance parameters based on a comparison of the test timing data and the reference timing test data.

[0009]

[0009] The above and other aspects of the present invention will be understood by considering the embodiments described below. [Brief explanation of the drawing]

[0010]

[0010] Embodiments of the present invention will be described only by reference to the accompanying drawings.

[0011] [Figure 1] This shows a lithography machine. [Figure 2] The measurement and exposure processes in the apparatus shown in Figure 1 are schematically illustrated. [Modes for carrying out the invention]

[0012]

[0011] Before describing embodiments of the present invention in detail, it is useful to show exemplary environments in which embodiments of the present invention can be carried out.

[0013]

[0012] Figure 1 schematically shows a lithography apparatus LA. The apparatus comprises an illumination system (illuminator) IL configured to adjust a radiation beam B (e.g., UV radiation or DUV radiation); a patterning device support or support structure (e.g., mask table) MT constructed to support a patterning device (e.g., mask) MA and connected to a first positioner PM configured to precisely position the patterning device according to specific parameters; two substrate tables (e.g., wafer tables) WTa and WTb configured to hold a substrate (e.g., resist-coated wafer) W and connected to a second positioner PW configured to precisely position the substrate according to specific parameters; a projection system (e.g., refractive projection lens system) PS configured to project the pattern applied to the radiation beam B by the patterning device MA onto a target portion C of the substrate W (e.g., including one or more dies); and a reference frame RF connecting various components and serving as a reference for setting and measuring the positions of the patterning device and the substrate and their features.

[0014]

[0013] The lighting system may include various types of optical components, such as refractive, reflective, magnetic, electromagnetic, electrostatic, or other types of optical components, or any combination thereof, for inducing, shaping, or controlling radiation.

[0015]

[0014] The patterning device support MT holds the patterning device in a manner that depends on conditions such as the orientation of the patterning device and the design of the lithography apparatus, for example, whether or not the patterning device is held in a vacuum environment. The patterning device support can use mechanical, vacuum, electrostatic, or other clamping techniques to hold the patterning device. The patterning device support MT may be, for example, a frame or a table, and may be fixed or movable as needed. The patterning device support can ensure that the patterning device is positioned reliably in the desired location relative to, for example, the projection system.

[0016]

[0015] The term “patterning device” as used herein should be interpreted broadly to refer to any device that can be used to impart a pattern to a cross-section of a radiation beam in order to generate a pattern on a target portion of a substrate. Note that the pattern imparted to the radiation beam may not precisely correspond to a desired pattern on the target portion of the substrate, for example, if the pattern includes phase-shift features or so-called assist features. Generally, the pattern imparted to the radiation beam corresponds to a specific functional layer of a device to be generated on the target portion, such as an integrated circuit.

[0017]

[0016] As shown herein, the device is of the transmissive type (for example, using a transmissive mask). Alternatively, the device may be of the reflective type (for example, using a programmable mirror array of the type mentioned above, or using a reflective mask). Examples of patterning devices include masks, programmable mirror arrays, and programmable LCD panels. Where the terms “reticle” or “mask” are used herein, these terms can be considered synonymous with the more general term “patterning device.” The term “patterning device” can also be interpreted as referring to a device that stores pattern information in digital format to control such a programmable patterning device.

[0018]

[0017] As used herein, the term “projection system” should be interpreted broadly to encompass a variety of projection systems, including refractive optical systems, reflective optical systems, reflective refractive optical systems, anamorphic optical systems, magneto-optical systems, electromagnetic optical systems, and / or electrostatic optical systems, or any combination thereof, as appropriate in accordance with the exposure radiation used and / or other factors such as the use of immersion liquid or vacuum. Where the term “projection lens” is used herein, it can be considered synonymous with the more general term “projection system.”

[0019]

[0018] The lithography apparatus may be of a type in which at least a portion of the substrate is covered with a liquid having a relatively high refractive index, such as water, so as to fill the space between the projection system and the substrate. The immersion liquid can also be applied to other spaces in the lithography apparatus, such as between the mask and the projection system. Immersion techniques are well known in the art to increase the numerical aperture of the projection system.

[0020]

[0019] During operation, the illuminator IL receives a radiation beam from the radiation source SO. The radiation source and the lithography apparatus may be separate components, for example, when the radiation source is an excimer laser. In such cases, the radiation source is not considered to form part of the lithography apparatus, and the radiation beam is delivered from the radiation source SO to the illuminator IL with the help of a beam delivery system BD, which includes, for example, a suitable guidance mirror and / or beam expander. In other cases, for example, when the radiation source is a mercury lamp, the radiation source may be an integral part of the lithography apparatus. The radiation source SO and the illuminator IL may, if necessary, be referred to as a radiation system together with the beam delivery system BD.

[0021]

[0020] The illuminator IL may include, for example, an adjuster AD, an integrator IN, and a capacitor CO for adjusting the angular intensity distribution of the radiated beam. The illuminator can be used to adjust the radiated beam to give it a desired uniformity and intensity distribution in its cross-section.

[0022]

[0021] The radiant beam B is incident on a patterning device MA held on a patterning device support MT, and a pattern is formed by the patterning device. The radiant beam B, having crossed the patterning device (e.g., mask) MA, passes through a projection system PS, which focuses the beam onto a target portion C of the substrate W. With the help of a second positioner PW and position sensors IF (e.g., interferometer, linear encoder, 2D encoder, or capacitive sensor), the substrate table WTa or WTb can be precisely moved so that, for example, various target portions C are positioned along the path of the radiant beam B. Similarly, a first positioner PM and another position sensor (not explicitly shown in Figure 1) can be used to precisely position the patterning device (e.g., mask) MA along the path of the radiant beam B, such as after mechanical removal from the mask library or during scanning.

[0023]

[0022] The lithography apparatus may include an aberration sensor for verifying the aberration fingerprint of the projection system PS. In one embodiment, such an aberration fingerprint, i.e., the aberration at each field of view of the projection system PS, may be determined using such a wavefront aberration sensor. For example, a known type of wavefront aberration sensor, such as that described in US2002 / 0001088, may be used. Such a wavefront aberration sensor may be based on the principle of shearing interferometry and includes a light source module and a sensor module. The light source module may include a patterned chrome layer positioned on the objective plane of the projection system PS (i.e., the plane on which the pattern of the patterning means is located during manufacturing) and an additional optical system provided above the chrome layer. This combination provides a radiating wavefront across the entire pupil of the projection system PS. The sensor module may include a patterned chrome layer positioned on the image plane of the projection system (i.e., the plane on which the substrate W is located during manufacturing) and a camera positioned at a distance behind the chrome layer. A patterned chromium layer on the sensor module diffracts radiation into multiple diffraction orders, which interfere with each other to produce an interferogram. The interferogram is measured by a camera. The aberration of the projection lens can be determined by software based on the measured interferogram. The wavefront aberration sensor may be configured to transfer information about the aberration fingerprint to a control unit.

[0024]

[0023] The patterning device (e.g., mask) MA and the substrate W can be aligned using mask alignment marks M1, M2 and substrate alignment marks P1, P2. Substrate alignment marks such as those shown occupy dedicated target portions, but may also be located in the space between the target portions (known as scribe line alignment marks). Similarly, in a situation where a plurality of dies are provided on the patterning device (e.g., mask) MA, the mask alignment marks may be arranged between the dies. Small alignment markers can also be included within the device features and even within the die, in which case the markers are desirably as small as possible and do not require a different imaging or process condition from adjacent features. The alignment system for detecting the alignment markers will be described in detail below.

[0025]

[0024] The illustrated apparatus can be used in various modes. In the scan mode, while synchronously scanning the patterning device support (e.g., mask table) MT and the substrate table WT, the pattern applied to the radiation beam is projected onto the target portion C (i.e., single dynamic exposure). The speed and direction of the substrate table WT relative to the patterning device support (e.g., mask table) MT can be determined by the (reduction) magnification and image inversion characteristics of the projection system PS. In the scan mode, the maximum size of the exposure field limits the width (non-scan direction) of the target portion during single dynamic exposure, while the length of the scan operation determines the height (scan direction) of the target portion. As is well known in the art, other types of lithographic apparatus and operating modes are conceivable. For example, the step mode is known. In so-called “maskless” lithography, the pattern is changed while keeping the programmable patterning device stationary, and the substrate table WT is moved or scanned.

[0026]

[0025] Combinations and / or variations of the above usage modes, or entirely different usage modes, may also be employed.

[0027]

[0026] The lithography apparatus LA is of a so-called dual-stage type and has two substrate tables WTa, WTb and two stations (exposure station EXP and measurement station MEA), and the substrate table can be exchanged between these stations. While one substrate on one substrate table is being exposed at the exposure station, the other substrate can be loaded onto the other substrate table at the measurement station and various preparation steps can be performed. Thereby, the throughput of the apparatus can be significantly increased. The preparation steps may include mapping the surface height profile of the substrate using the level sensor LS and measuring the position of the alignment markers on the substrate using the alignment sensor AS. If the position sensor IF cannot measure the position of the substrate table at the measurement station in addition to the measurement at the exposure station, a second position sensor may be provided to enable tracking of the position of the substrate table at both stations with respect to the reference frame RF. Instead of the illustrated dual-stage configuration, other configurations are known and can be used. For example, other lithography apparatuses having a substrate table and a measurement table are known. These are engaged with each other when performing the preparation measurement, and then the engagement is released while the substrate table is being exposed.

[0028]

[0027] FIG. 2 shows the steps of exposing a target portion (e.g., a die) on the substrate W in the dual-stage apparatus of FIG. 1. The inside of the left dotted line frame shows the steps performed at the measurement station MEA, and the right side shows the steps performed at the exposure station EXP. Thus, sometimes one of the substrate tables WTa, WTb is at the exposure station and the other is at the measurement station. For the purpose of this description, it is assumed that the substrate W has already been loaded at the exposure station. In step 200, a new substrate W' is loaded into the apparatus by a mechanism not shown. By processing these two substrates in parallel, the throughput of the lithography apparatus is improved.

[0029]

[0028] First, the newly loaded substrate W' may be an untreated substrate, prepared with new photoresist for the first exposure in the apparatus. However, since the lithography process described above is generally only one step in a series of exposure and processing steps, the substrate W' may have already been processed several times in this apparatus and / or other lithography apparatus and may undergo further steps thereafter. In particular, in the challenge of improving overlay performance, it is required that a new pattern be applied precisely to the correct position on a substrate that has already undergone one or more patterning and processing cycles. These processing steps sequentially introduce distortions in the substrate that need to be measured and corrected, so in order to achieve satisfactory overlay performance, the distortions need to be measured and corrected.

[0030]

[0029] As mentioned above, the preceding and / or subsequent patterning steps may be performed in other lithography equipment, or in different types of lithography equipment. For example, some layers in a device manufacturing process that are very demanding in terms of parameters such as resolution and overlay may be processed with more advanced lithography tools than other layers that are not so demanding. For this reason, some layers may be exposed with an immersion lithography tool, and other layers may be exposed with a "dry" lithography tool. Some layers may be exposed with a tool operating at a DUV wavelength, and other layers may be exposed using radiation at an EUV wavelength.

[0031]

[0030] In 202, the alignment of the substrate with respect to the substrate table WTa / WTb is measured and recorded by measuring the substrate mark P1 etc. and the alignment measurement using an image sensor (not shown). In addition, multiple alignment marks on the substrate W' are measured using the alignment sensor AS. In one embodiment, these measurements are used to establish a "wafer grid" that maps the distribution of marks on the substrate very accurately, including distortion with respect to a nominal rectangular grid.

[0032]

[0031] In step 204, a map of wafer height (Z) relative to the XY position is measured using the level sensor LS. Conventionally, height maps have been used only to achieve accurate focusing of the pattern being exposed. Height maps may be used for other purposes.

[0033]

[0032] When the substrate W' is loaded, recipe data 206 is received that defines the exposure to be performed, the characteristics of the wafer, and the characteristics of the patterns already formed on the wafer and the patterns to be formed. Measurement results of the wafer position, wafer grid, and height map measured in 202, 204 are added to this recipe data, and a complete set of recipe and measurement data 208 can be passed to the exposure station EXP. Alignment data measurements include, for example, the X and Y positions of alignment markers formed in a fixed or nominally fixed relationship with respect to the product pattern formed as a result of the lithography process. These alignment data acquired immediately before exposure are used to generate an alignment model using parameters that fit the model to the data. These parameters and alignment model are used during the exposure operation to correct the position of the pattern applied in the current lithography step. The model used interpolates the positional deviation between the measured positions. Conventional alignment models include four, five, or six parameters in different dimensions, which define the translation, rotation, and scaling of the "ideal" grid. More advanced models using a greater number of parameters are known.

[0034]

[0033] In step 210, wafer W' is replaced with wafer W, so that the measured substrate W' becomes the substrate W that is loaded into the exposure station EXP. In the exemplary apparatus of Figure 1, this replacement is performed by replacing supports WTa and WTb within the apparatus, so that substrates W and W' are kept precisely clamped and positioned on these supports, and the relative alignment between the substrate table and the substrate itself is maintained. Thus, once the table is replaced, the measurement information from steps 202 and 204 regarding substrate W (formerly W') becomes available in controlling the exposure step, by only determining the relative position between the projection system PS and the substrate table WTb (formerly WTa). In step 212, reticle alignment is performed using mask alignment marks M1 and M2. In steps 214, 216, and 218, a scanning operation is performed at sequential target positions on the substrate W, and radiation pulses are applied to complete the exposure of multiple patterns.

[0035]

[0034] These patterns are precisely aligned to desired positions, particularly to features previously formed on the same substrate, by using alignment data and height maps acquired at the measurement station during the exposure step. The exposed substrate, labeled here as W, is removed from the apparatus in step 220 and subjected to etching or other processing according to the exposure pattern.

[0036]

[0035] Those skilled in the art will understand that the above description is a simplified overview of many very detailed steps included in an example of an actual manufacturing site. For example, alignment is often measured in separate stages of rough and fine measurements using the same or different marks, rather than in a single pass. The rough alignment measurement and / or fine alignment measurement steps can be performed before or after the height measurement, or alternately.

[0037]

[0036] Typically, there are many actions and events that prompt the qualification of an exposure system. For example, such qualification may be performed before or as part of the installation of an exposure system in the field or manufacturing plant, and / or after maintenance work has been performed. Such maintenance work may include, for example, the replacement of hardware components that degrade over time (e.g., wafer tables or projection lenses), or the replacement or updating of software modules. Qualification of an exposure system may also be performed when developing a new product (e.g., hardware and / or software modules).

[0038]

[0037] At the system level, such qualification actions may measure the final performance of the exposure apparatus in terms of system-level performance parameters. These system-level performance parameters may include productivity performance parameters (e.g., those related to productivity or speed) and several quality performance parameters, namely focus performance, imaging performance, defect performance, and overlay performance. At the module level, more critical quality characteristic (CtQ) parameters can be measured.

[0039]

[0038] In the context of this disclosure, qualification may include qualification of any exposure apparatus, or any module or other component. The exposure apparatus may comprise one or more lithography apparatuses, such as a lithography apparatus (for example, one that prints by exposure) or a lithography apparatus such as a scatrometer or scanning electron microscope / e-beam apparatus (for example, one that measures by exposure).

[0040]

[0039] Currently, many different tests are performed to measure these individual parameters, which consumes a great deal of time and resources. For example, to qualify focus performance, it is known that an alignment sensor is used to measure the focus setting used to expose a special type of focus-sensitive alignment mark or focus mark. Many of these marks may be exposed and read during the focus test procedure. Such a procedure can take several hours, during which time the tool is offline. Qualification tests for other system-level performance parameters may take similar or even longer.

[0041]

[0040] Therefore, it is desirable to shorten the time required for qualification. For example, it is known to use a Fast Ship strategy for system installation that omits some of these qualification steps. While this shortens the time, it increases the risk of overlooking performance issues. Therefore, it is desirable to develop a new qualification method that is short in duration but does not lead to an unacceptable decline in quality.

[0042]

[0041] Whether it is the integration of a new product, the qualification of a software service pack, or factory shipment, one of the qualification tests that is typically performed is the productivity qualification test, also known as the endurance productivity test or endurance ATP productivity test. This test is particularly desirable because productivity performance is a particularly important performance criterion. Furthermore, the productivity qualification test is a relatively inexpensive test, and the machine time is usually around 20 to 35 minutes.

[0043]

[0042] Productivity qualification tests may include (e.g., dummy) exposure on multiple wafers. Exposure may be performed using multiple (e.g., two) different reticles, each having a different pattern. Exposure may be dummy exposure, as long as no resist is applied to the wafers, but otherwise should be substantially identical to actual exposure. Exposure may be performed on lots of multiple wafers, each lot relating to multiple wafers (e.g., 5 to 15 wafers per lot, the number of which may vary from lot to lot within the test). Since exposure may be dummy exposure, the number of physical wafers actually used may be small (e.g., fewer than 20, fewer than 10, fewer than 5, usually 4), and each wafer may be exposed multiple times during the test, sometimes simulating the exposure of multiple lots of wafers (e.g., more than 40, more than 50, or more than 60). Different lots may relate to different configurations, different reticles (which may include reticle changes in the middle of a lot), and / or different numbers of wafers (e.g., reused).

[0044]

[0043] The primary objective of productivity qualification testing is to derive performance in relation to productivity specifications. In particular, productivity qualification testing may measure and qualify productivity (e.g., speed) in terms of wafer throughput (e.g., wafers / hour). Furthermore, the test may individually quantify other productivity metrics, such as determining the time overhead caused by either or both reticle changes and / or lot changes.

[0045]

[0044] However, it is found that during productivity qualification testing, a large number of low-level timing and duration (test time data) related to various actions during system operation are recorded. For this reason, it has been proposed that system qualification actions relating to the exposure apparatus, apparatus, or its components be performed based on test timing data describing one or more system action durations, each system action duration describing the duration of the respective system action, in terms of qualifying one or more (system-level) quality performance parameters (e.g., focus, imaging, defects, overlay). Such test timing data may be timing data normally obtained as a result of conducting productivity qualification testing and may include (for example) the time taken to perform system actions such as wafer clamping, exposure scanning, preparation movement, reticle alignment, lens correction adjustment, wafer transport (e.g., from wafer handler to wafer table) and / or movement of any system component of the exposure apparatus. It may be recognized that some of the CtQ parameters that affect the other four system-level performance parameters (focus, imaging, defects, and overlay) have timing components associated with them.

[0046]

[0045] Thus, the inventors recognize that many performance issues can be determined by analyzing these low-level timing or test timing data, and therefore, based on this test timing data, conclusions can be drawn about the performance of the tool and / or potential quality issues can be predicted.

[0047]

[0046] The advantage of using these low-level timings is that there is generally a predictable / logical relationship between these timings and one or more of the performance parameters of interest (quality performance parameters). Furthermore, the individual timing measurements included in the test timing data often have less variability (e.g., noise) compared to performance metrics such as overlays and the number of defects per wafer (which are generally more probabilistic).

[0048]

[0047] As a first concrete example, it can be shown that (e.g., immersion) defect performance is highly dependent on the exposure meandering route. This exposure meandering route can be broken down into two field-by-field periods in the test timing data, namely the exposure scan period and the preparation move period. Any changes in these periods (e.g., statistically significant or exceeding expectations due to wafer-to-wafer variability) suggest a slight change in the route and carry a defect risk. Thus, defects can be evaluated or predicted by monitoring these periods, which are typically recorded during productivity qualification testing. Therefore, these two field-by-field periods can be used to qualify defect performance parameters.

[0049]

[0048] For example, consider a case where a bug is introduced into the routing software by a software update. This bug causes a chasing motion instead of the desired diagonal movement during the exposure of one or more (e.g., edge) fields. These different movements are reflected in the timing of the exposure scan period and the preparation period. Therefore, anomalies can be detected by measuring the timing difference, and each defective performance issue can be flagged. This makes it possible to detect the bug and trigger further analysis to properly identify, for example, unintended route changes.

[0050]

[0049] As another specific example, the wafer clamping and / or wafer adjustment steps, for example, the time spent in a wafer handling module on a wafer table, are known to potentially affect the overlay. These timing changes may indicate changes in the thermal state of the wafer, as the wafer may be adjusted (e.g., to a desired temperature) within the wafer handling module, and the longer the time required for this, the more likely it is to indicate a thermal problem. Such thermal issues may correlate with overlay performance. In particular, the time from transporting the wafer to the wafer handling module to clamping the wafer on the wafer table may be used to qualify for such overlay performance.

[0051]

[0050] Another timing parameter that may be monitored during productivity qualification testing and used for non-productivity qualification is the time required to perform lens adjustments in response to lens aberration measurements (e.g., using a lens aberration sensor or wavefront sensor). A longer (or less common) adjustment period than expected may indicate larger or unexpected lens aberrations. This can be a predictor or judge for one or more quality performance parameters such as focus, imaging, defects, and overlay.

[0052]

[0051] Another example may be the timing of reticle alignment (e.g., the time required to perform reticle alignment or the associated period). During reticle alignment, the wafer stage is typically temporarily positioned by placing one sensor in the immersion liquid beneath the lens. This can change the thermal adjustment of the sensor, resulting in deformation. If this adjustment time, i.e., sensor deformation, differs from wafer to wafer, measurement errors between wafers may occur.

[0053]

[0052] Furthermore, if the lithography tool is an immersion tool, any sensor component that is heated may be located near the immersion chamber for a longer time than desired, which may affect its thermal conditioning. Therefore, any time parameter relating to the length of time required for the movement and / or alignment of such components may be used in the qualification in accordance with the teachings herein.

[0054]

[0053] These are just a few examples, and there are many timing parameters monitored during productivity qualification testing, many or all of which are directly linked to or correlated with one or more system-level quality performance parameters (e.g., non-productivity and / or in addition to productivity) being targeted. In this way, (at least partial) system qualification can be performed without performing other qualification tests that are typically used to directly qualify one or more of the quality performance parameters among focus, imaging, defects, and / or overlay.

[0055]

[0054] In any case, the analysis of the test timing data may include determining statistically significant timing deviations that are not due to normal wafer-to-wafer variability. The analysis can also be performed field by field, but although the timing parameters may differ for each field on the wafer due to field position, field sequence, etc., it is understood that the values ​​for each field should not vary significantly from wafer to wafer.

[0056]

[0055] Such a method may include determining representative field-specific test timing data (e.g., the field-specific average for all wafers or a subset thereof used in the test). This may be done individually for each test timing under consideration. This representative test timing data can be compared with reference test timing data to obtain comparative test timing data. For example, this step may include determining comparative test timing data as post-pre-test timing data that includes the difference between representative test timing data (post-data, e.g., after a software update, component replacement, upgrade, or other maintenance work) and reference test timing data (pre-data, e.g., before a software update, component replacement, upgrade, or other maintenance work). The reference data may be obtained from one or more other (similar) machines. For example, if the qualification is for the installation of a new machine, the reference data may be obtained from a previously installed similar machine. The wafer-to-wafer variability observed in representative and reference test timing data may be determined according to any appropriate statistical measurement; for example, a confidence interval may be defined by considering wafer-to-wafer variability within 3σ (three standard deviations) as "normal." Any deviation in the confidence level of the test timing data outside this confidence interval may be flagged as a potential problem with one or more relevant system-level quality performance parameters. Of course, this is merely an example, and other appropriate methods may be used to determine statistical significance.

[0057]

[0056] Although specific embodiments of the present invention have been described above, it should be understood that the present invention can also be put into practice in ways other than those described.

[0058]

[0057] While we have made particular reference to the use of embodiments of the present invention in the field of optical lithography, it should be understood that the present invention can be used in other fields, such as imprint lithography, depending on the context, and is not limited to optical lithography. In imprint lithography, a topography in a patterning device defines the pattern to be created on a substrate. The topography of the patterning device is imprinted into a resist layer supplied to the substrate, and the resist is cured by applying electromagnetic radiation, heat, pressure, or a combination thereof. The patterning device is removed from the resist, and once the resist has cured, the pattern remains inside.

[0059]

[0058] As used herein, the terms “radiation” and “beam” encompass all types of electromagnetic radiation, including not only particle beams such as ion beams or electron beams, but also ultraviolet (UV) radiation (e.g., having wavelengths of 365 nm, 355 nm, 248 nm, 193 nm, 157 nm or 126 nm, or around these wavelengths) and extreme ultraviolet (EUV) radiation (e.g., having wavelengths in the range of 1 nm to 100 nm).

[0060]

[0059] The term “lens” can refer to any one or a combination of various types of optical components, including refractive, reflective, magnetic, electromagnetic, and electrostatic-optical components, where circumstances permit. Reflective components are likely to be used in devices operating in the UV and / or EUV region.

[0061]

[0060] The scope and width of the present invention are not limited by any of the exemplary embodiments described above, but are defined solely by the claims and their equivalents.

Claims

1. A method for performing a system qualification action relating to an exposure apparatus or its components, Obtaining test timing data for one or more test timing parameters, where each test timing parameter describes a system action period, and each system action period describes the duration of a system action of the exposure apparatus or its components. To obtain reference timing test data including reference values ​​for one or more system action periods, A method comprising: evaluating the exposure apparatus or its components from the viewpoint of one or more quality performance parameters based on a comparison of the test timing data with the reference timing test data.

2. The method according to claim 1, wherein the test timing data includes timing data obtained as a result of conducting a productivity qualification test.

3. The method according to claim 2, further comprising the initial step of conducting the productivity qualification test and obtaining the test timing data.

4. The method according to any one of claims 1 to 3, wherein the quality performance parameter includes one or more of the focus performance parameter, imaging performance parameter, defect performance parameter, and / or overlay performance parameter.

5. The method according to any one of claims 1 to 4, wherein the test timing data includes one or more of the following: wafer clamping period data, exposure scan period data, preparation move period data, reticle alignment period data, lens correction adjustment period data, wafer transfer period data, and / or any period relating to the movement of the system components of the exposure apparatus.

6. The aforementioned qualification assessment is performed by To determine whether the aforementioned test timing data deviates from the aforementioned reference timing test data, The method according to any one of claims 1 to 5, comprising flagging a potential problem in terms of one or more quality performance parameters if the test timing data deviates from the reference timing test data.

7. The method according to claim 6, wherein determining whether the test timing data deviates from the reference timing test data includes determining whether the test timing data deviates statistically significantly from the reference timing test data.

8. Regarding the aforementioned test timing data, a confidence interval is determined that describes the variation for each normal substrate, The method according to claim 7, comprising determining a statistically significant deviation as one that deviates outside the confidence interval.

9. The method according to any one of claims 1 to 8, wherein the qualification assessment is performed individually for each of the one or more test timing parameters in the test timing data.

10. The method according to any one of claims 1 to 9, wherein the test timing data includes representative test timing data that describes average test timing data across multiple substrates.

11. The method according to any one of claims 1 to 10, wherein the test timing data includes test timing data for each field, and the comparison between the test timing data and the reference timing test data is performed for each field.

12. The method according to any one of claims 1 to 11, wherein the test timing data includes test timing data relating to the exposure apparatus or its components after maintenance work, and the reference timing test data includes test timing data relating to the exposure apparatus or its components before maintenance work.

13. The method according to any one of claims 1 to 12, wherein the reference timing test data includes timing test data relating to at least one exposure apparatus or component different from the exposure apparatus or component thereof used to acquire the timing test data.

14. A computer program comprising program instructions that, when executed on a suitable device, are operable to perform the method described in any one of claims 1 to 13.

15. A non-temporary computer program recording medium containing the computer program described in claim 14.

16. A non-temporary computer program recording medium including a computer program which includes program instructions that, when executed on a suitable device, are operable to perform the method described in any one of claims 1 to 13, A processor capable of executing the computer program contained in the non-temporary computer program recording medium, A processing configuration comprising the following:

17. An exposure apparatus comprising the processing configuration described in claim 16.

18. The exposure apparatus according to claim 17, comprising a lithography apparatus.

19. The exposure apparatus according to claim 17, comprising a metronome device.

20. A semiconductor device manufactured using the exposure apparatus described in claim 17, 18, or 19.

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