Determination method, information processor and program

Abstract

To provide a technology advantageous for determining a range within which a treatment regarding search of a mark provided on a substrate that is treated by a lithography device is performed.SOLUTION: A determination method includes: a first step of obtaining first processing data obtained by applying first processing conditions to a first lithography apparatus to process a substrate, second processing data obtained by applying second processing conditions, which are different from the first processing conditions to process the substrate, and third processing data that can be obtained by applying the first processing conditions to a second lithography apparatus that is different from the first lithography apparatus; a second step of predicting the probability distribution of fourth processing data obtained by applying the second processing conditions to the second lithography apparatus based on the first processing data, the second processing data, and the third processing data; a third step of determining the range of processing related to the search of marks provided on the substrate when applying the second processing conditions to the second lithography apparatus to process the substrate based on the predicted probability distribution of the fourth processing data from the second step.SELECTED DRAWING: Figure 5

Description

[Technical field]

[0001] The present invention relates to a determination method, an information processing device, and a program. [Background technology]

[0002] In the manufacture of devices (articles) such as semiconductor devices, MEMS, and flat panel displays, patterns formed on substrates are becoming increasingly fine, and lithography apparatuses are being required to improve their performance in terms of resolution, overlay accuracy, productivity, etc. In recent years, there has also been a demand for the manufacture of a wide variety of devices in a short period of time, and there is a particular demand for improved productivity.

[0003] Therefore, in device manufacturing lines, diagnostic devices that diagnose manufacturing equipment including exposure equipment and process processing equipment are being introduced with the aim of efficiently manufacturing devices with excellent characteristics and improving the operating rate of the equipment to increase the yield. Such diagnostic devices collect various data from manufacturing equipment, inspection equipment, measurement equipment, etc., analyze the data to grasp the situation, and adjust control parameters, etc. (see Patent Document 1). This makes it possible to predict the future status of the equipment from the results obtained by analyzing, grasping, and statistically analyzing the operating status and trends of the equipment, suppress (prevent) the occurrence of abnormalities, and optimize the processing sequence, thereby improving productivity (yield). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 6808684 Summary of the Invention [Problem to be solved by the invention]

[0005] However, data collected from manufacturing equipment, inspection equipment, measurement equipment, etc. is affected by multiple factors (e.g., exposure equipment, etching equipment, resist coating equipment, etc.), and it is difficult to separate these factors. Therefore, data must be collected for each combination of factors, and it takes time to adjust control parameters (set conditions), for example, to determine the range of processing related to searching for marks used in substrate positioning (alignment, focus).

[0006] The present invention has been made in consideration of the problems with the conventional technology, and has an exemplary object to provide a technique that is advantageous for determining the range in which processing related to searching for a mark provided on a substrate processed by a lithography apparatus is performed. [Means for solving the problem]

[0007] In order to achieve the above-mentioned object, a determination method as one aspect of the present invention is a determination method for determining a range for performing processing related to a search for a mark provided on a substrate processed by a lithography apparatus, the determination method comprising: a first step of acquiring first processing data obtained by applying first processing conditions to a first lithography apparatus to perform processing on a substrate, second processing data obtained by applying second processing conditions different from the first processing conditions to the first lithography apparatus to perform the processing on the substrate, and third processing data obtained by applying the first processing conditions to a second lithography apparatus different from the first lithography apparatus to perform the processing on the substrate; a second step of predicting a probability distribution of fourth processing data obtained by applying the second processing conditions to the second lithography apparatus to perform the processing based on the first processing data, the second processing data, and the third processing data; and a third step of determining a range for processing related to a search for a mark provided on the substrate when applying the second processing conditions to the second lithography apparatus to perform processing on the substrate based on the probability distribution of the fourth processing data predicted in the second step.

[0008] Further objects or other aspects of the present invention will become apparent from the following description of the embodiments with reference to the accompanying drawings. Effect of the Invention

[0009] According to the present invention, for example, a technique is provided that is advantageous for determining the range within which a lithographic apparatus performs processing related to searching for a mark provided on a substrate being processed. [Brief description of the drawings]

[0010] [Figure 1] 1 is a block diagram showing a configuration of a lithography system to which the present invention is applied. [Diagram 2] FIG. 1 is a diagram showing a configuration of an exposure apparatus. [Diagram 3] FIG. 2 is a diagram illustrating a hardware configuration of an information processing device. [Figure 4] FIG. 2 is a diagram illustrating a configuration of a CPU of an information processing device. [Diagram 5] 1 is a flow chart illustrating a method for predicting a probability distribution of data related to a lithography process. [Figure 6] FIG. 4 is a diagram showing an example of lot data. [Figure 7] FIG. 11 is a diagram illustrating an example of accumulated data. [Figure 8] 13 is a diagram showing a probability distribution of the detection positions of the alignment marks predicted by a prediction section. FIG. [Figure 9] 11 is a diagram showing the relationship between an alignment mark and an image processing range in which pattern matching processing is performed. FIG. [Figure 10] 13 is a diagram showing a probability distribution of focus positions predicted by a prediction unit. FIG. [Figure 11] FIG. 11 is a diagram showing a range in which an evaluation value for determining a focus position should be calculated; [Figure 12] FIG. 11 is a diagram illustrating an example of accumulated data. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] Hereinafter, the embodiments will be described in detail with reference to the attached drawings. Note that the following embodiments do not limit the invention according to the claims. Although the embodiments describe a number of features, not all of these features are essential to the invention, and the features may be combined in any manner. Furthermore, in the attached drawings, the same reference numbers are used for the same or similar configurations, and duplicated descriptions are omitted.

[0012] Fig. 1 is a block diagram showing the configuration of a lithography system LS to which the present invention is applied. The lithography system LS is a system used in the manufacture of devices such as semiconductor devices, MEMS, and flat panel displays as articles, and performs lithography processing on a substrate. As shown in Fig. 1, the lithography system LS has multiple lithography apparatuses 100 and an information processing apparatus 200.

[0013] First, as an example of the lithography apparatus 100, an exposure apparatus that exposes a wafer (substrate) with light from a reticle (original, mask) on which a pattern is formed will be described. It should be noted that the lithography apparatus 100 is not limited to an exposure apparatus. For example, the lithography apparatus includes an imprint apparatus that forms a pattern on a substrate by molding an imprint material on the substrate with a mold, and a planarization apparatus that planarizes a composition on the substrate using a mold having a flat surface. The lithography apparatus also includes a drawing apparatus that draws a pattern on a substrate using a charged particle beam (such as an electron beam or an ion beam).

[0014] 2 is a diagram showing the configuration of an exposure apparatus EX as an example of the lithography apparatus 100. In this embodiment, the exposure apparatus EX is described as a step-and-scan type exposure apparatus (scanner) that exposes a wafer while synchronously driving (scanning) a reticle stage and a wafer stage. However, the exposure apparatus EX is not limited to a scanner, and may be a step-and-repeat type exposure apparatus (stepper) that exposes a wafer while the wafer stage is stationary.

[0015] 2, the exposure apparatus EX has an illumination optical system 8 that illuminates the reticle 1 with light from a light source 7, a reticle stage 2, a projection optical system 3, a wafer chuck 5, a wafer stage 6, and a control unit 16. The exposure apparatus EX also has laser interferometers 9 and 10, a focus sensor 11, a wafer transport unit 12, a reticle transport unit 14, and an alignment scope 15. In Fig. 2, the direction parallel to the optical axis of the projection optical system 3 is defined as the Z direction, and two directions perpendicular to each other in a plane perpendicular to the Z direction are defined as the X direction and the Y direction.

[0016] The light source 7 includes, for example, a high-pressure mercury lamp, an ArF excimer laser, a KrF excimer laser, etc. The light source 7 may be disposed inside or outside the chamber of the exposure apparatus EX. The light emitted from the light source 7 illuminates the reticle 1 via an illumination optical system 8.

[0017] A pattern to be transferred to a wafer 4 is formed (drawn) on a reticle 1. A reticle stage 2 holds the reticle via a reticle chuck (not shown). The reticle stage 2 is configured to be drivable by, for example, a linear motor (not shown).

[0018] The projection optical system 3 projects an image of the pattern of the reticle 1 onto the wafer 4 held by a wafer chuck 5. An image of the pattern of the reticle 1, which is inverted and reduced at a projection magnification (for example, 1 / 4), is projected onto the wafer 4 via the projection optical system 3. If the area on the wafer onto which the image of the pattern of the reticle 1 is projected is defined as a shot area, multiple shot areas are set on the wafer 4, and the image of the pattern of the reticle 1 is repeatedly projected onto each shot area.

[0019] The wafer stage 6 is configured to be drivable in the X and Y directions by, for example, a linear motor (not shown). The wafer chuck 5 is supported by the wafer stage 6 and holds the wafer 4. The wafer stage 6 positions the wafer chuck 5 in the Z direction, θ direction, ωX direction, and ωY direction. In this manner, the wafer 4 held by the wafer chuck 5 is aligned by driving the wafer stage 6 (wafer chuck 5).

[0020] A laser interferometer 9 measures the position of the reticle stage 2 in the X and Y directions, and the attitude of the reticle stage 2. A laser interferometer 10 measures the position of the wafer stage 6 in the X and Y directions, and the attitude of the wafer stage 6. The relative positions and attitudes of the reticle stage 2 and the wafer stage 6 are controlled by a control unit 16 based on the positions and attitudes measured by the laser interferometers 9 and 10.

[0021] The focus sensor 11 includes a light projection system 11a that irradiates light (multiple beams) onto the wafer 4, and a detection system 11b that detects light (reflected light) from the wafer 4. The light projection system 11a and the detection system 11b are arranged to sandwich the vicinity of the emission part (end part on the wafer side) of the projection optical system 3. The light projection system 11a irradiates the wafer 4 with light at an oblique incidence, and the detection system 11b detects the light reflected by the wafer 4 on the opposite side. Based on the detection signal output from the focus sensor 11, the control unit 16 determines the position of the wafer 4 in the Z direction (height direction) and controls the position (focus) of the wafer stage 6 in the Z direction.

[0022] The wafer transfer unit 12 has a function of transferring the wafer 4. The wafer transfer unit 12 transfers the wafer 4 between a wafer storage container (not shown) that stores the wafer 4 and the wafer stage 6.

[0023] The reticle transport unit 14 has a function of transporting the reticle 1. The reticle transport unit 14 transports the reticle 1 between a reticle storage container (not shown) that stores the reticle 1 and the reticle stage 2.

[0024] The alignment scope 15 captures an image of a mark provided on the wafer 4 to obtain a digital image signal (detection signal) in order to align the wafer 4 held by the wafer chuck 5. The alignment scope 15 includes an image sensor that outputs an image signal according to the brightness, i.e., the shading, of the light (reflected light) from the wafer 4, and an A / D converter that converts the image signal output from the image sensor into a digital image signal. Based on the digital image signal obtained by the alignment scope 15, the control unit 16 determines the positions of the mark (wafer 4) on the wafer 4 in the X and Y directions, and controls the positions of the wafer stage 6 in the X and Y directions.

[0025] The control unit 16 controls the operation and adjustment of each part of the exposure apparatus EX. The control unit 16 is, for example, an information processing device configured by a PLD (abbreviation for Programmable Logic Device) such as an FPGA (abbreviation for Field Programmable Gate Array), an ASIC (abbreviation for Application Specific Integrated Circuit), a computer with a program installed, or a combination of all or part of these. The control unit 16 may be configured by a plurality of information processing devices. The control unit 16 may be configured integrally with other parts of the exposure apparatus EX (in a common housing), or may be configured separately from other parts of the exposure apparatus EX (in a different housing).

[0026] The control unit 16 performs an exposure process (lithography process) in which the wafer 4 is exposed by applying the process conditions acquired from a storage device or the like. The process conditions applied to the exposure process include, for example, transport conditions that define the speed and path when the wafer 4 is transported to the wafer stage 6 by the wafer transport unit 12. The process conditions applied to the exposure process include, for example, alignment conditions that define the allowable error when the wafer 4 is aligned (positioned) by the wafer stage 6. The process conditions applied to the exposure process include, for example, measurement conditions that define the light irradiation time and irradiation timing when the focus sensor 11 measures the position of the wafer 4 in the Z direction. The process conditions applied to the exposure process include measurement conditions that define the image capture time and image capture timing of the mark when the alignment scope 15 measures the positions of the wafer 4 in the X direction and the Y direction. The process conditions applied to the exposure process include, for example, exposure conditions that define the identifier of the reticle 1 when the wafer 4 is exposed, the layout of the shot area of ​​the wafer 4, the illumination mode, and the like. Furthermore, the processing conditions applied to the exposure process include, for example, environmental conditions that define the temperature and air pressure inside the exposure apparatus, and setup conditions that include information such as the model of the exposure apparatus and the software version.

[0027] Next, the information processing device 200 will be described. Fig. 3 is a diagram showing a hardware configuration of the information processing device 200. Each piece of hardware in the information processing device 200 functions according to a program. The information processing device 200 includes a CPU 210, a ROM 220, a RAM 230, a storage device 240, an input device 250, a display device 260, and a communication device 270.

[0028] The CPU 210 is a processing device (processing unit) that performs calculations for control according to a program and controls each component connected to the bus. The ROM 220 is a memory for reading data. Programs and data are stored in the ROM 220. The RAM 230 is a memory for reading and writing data. The RAM 230 is used to store programs and data, for example, to temporarily store data such as the results of calculations by the CPU 210. The storage device 240 is used to store programs and data. The storage device 240 is also used as a temporary storage area for programs and data of the operating system (OS) of the information processing device 200. The storage device 240 is slower in data input / output than the RAM 230, but is capable of storing large amounts of data. The storage device 240 is preferably a non-volatile storage device that can store data as permanent data so that the data can be stored and referenced for a long period of time. The storage device 240 is mainly composed of a magnetic storage device (HDD), but may also be a device that loads external media such as CDs, DVDs, and memory cards to read and write data. The input device 250 is a device for inputting characters and data to the information processing device 200, and includes, for example, various keyboards and mice. The display device 260 is a device for displaying information required for operating the information processing device 200 and processing results, and includes, for example, a CRT or liquid crystal monitor. The communication device 270 is connected to a network and performs data communication using a communication protocol such as TCP / IP, and is used when communicating with other information processing devices. The information processing device 200 may also be configured with a GPU (abbreviation for Graphics Processor Unit) to enable high-speed arithmetic processing.

[0029] The information processing device 200 is connected to a plurality of lithography apparatuses 100 in order to communicate data via a communication device 270. In this embodiment, the information processing device 200 causes a CPU 210 to function as an acquisition unit 211, a storage unit 212, an analysis unit 213, and a prediction unit 214, as shown in Fig. 4. Fig. 4 is a diagram showing the configuration of the CPU 210 of the information processing device 200.

[0030] First Embodiment As the first embodiment, a method for predicting a probability distribution of data related to lithography processing by the information processing device 200 will be described. Fig. 5 is a flowchart for explaining a method for predicting a probability distribution of data related to lithography processing.

[0031] In S501, the acquisition unit 211 acquires lot data from the exposure apparatus EX serving as the lithography apparatus 100. The acquisition unit 211 also acquires, together with the lot data, information that identifies the exposure apparatus EX and information that identifies the processing conditions that were applied when the lot data was acquired. Furthermore, the acquisition unit 211 may acquire information that identifies the pre-processing apparatus that performed the pre-processing of the lot for which the lot data was acquired.

[0032] Here, the lot data will be described with reference to FIG. 6. FIG. 6 is a diagram showing an example of the lot data. When exposing a wafer 4 using the exposure apparatus EX, the wafer 4 is handled as a unit called a lot including a plurality of wafers 4 (for example, 25 wafers 4). When exposing a plurality of wafers 4 belonging to the same lot, the same processing conditions are applied. A layout of a plurality of shot areas as areas to be exposed on the wafer 4 is determined in advance, and the exposure apparatus EX repeats the exposure process on the plurality of shot areas on the wafer 4. Note that, in FIG. 6, the number of wafers 4 belonging to the lot is 25, and the number of shot areas on the wafer 4 is 100, but this is not limited to this.

[0033] The lot data is a collection (data group) of data (hereinafter referred to as "collected data") collected when exposure is performed by applying the same processing conditions to multiple wafers 4 belonging to a lot. The lot data has a hierarchical structure, and the collected data is classified and stored for each wafer and each shot area. In Fig. 6, the collected data includes synchronization accuracy data and illuminance data classified and stored for each shot area, and stage deviation data and alignment measurement data classified and stored for each wafer.

[0034] The synchronization accuracy data is data that indicates the error in the relative positions of the reticle stage 2 and the wafer stage 6 during a period in which the reticle stage 2 and the wafer stage 6 are driven synchronously, for example, in the Y direction, in order to expose a target shot area. The synchronization accuracy data is found in the control unit 16 based on stage deviation data relating to the reticle stage 2 and the wafer stage 6 that is collected during a period in which the reticle stage 2 and the wafer stage 6 are driven synchronously. If the error in the relative positions of the reticle stage 2 and the wafer stage 6 becomes large, this affects the overlay performance and image performance, and therefore by monitoring the synchronization accuracy data, it is possible to determine an abnormality in the exposure apparatus EX.

[0035] The illuminance data is data indicating the intensity of light irradiated onto the shot area during the period in which the shot area is exposed. Note that the illuminance data is calculated, for example, in the control unit 16 based on the measurement result of a light quantity sensor (not shown) that measures the intensity of light arranged in the illumination optical system 8 during the period in which the shot area is exposed.

[0036] The stage deviation data is data indicating the deviation between a target position and a measurement position regarding the control of at least one of the reticle stage 2 and the wafer stage 6 during the period in which the wafer 4 is exposed. Note that the stage deviation data is calculated, for example, in the control unit 16 based on the measurement results of the laser interferometers 9 and 10.

[0037] The alignment measurement data refers to data indicating waveform data of a digital image signal obtained by imaging a mark on the target wafer 4 and an evaluation of the digital image signal (symmetry of the waveform data, contrast of the digital image signal). The alignment measurement data is obtained, for example, in the control unit 16 based on the measurement results of the alignment scope 15.

[0038] The collected data is not limited to synchronization accuracy data, illuminance data, stage deviation data, and alignment measurement data. The collected data may be, for example, time-series data, or at least one of a maximum value, a minimum value, an average value, a median value, and a standard deviation calculated from the time-series data.

[0039] The lot data is collected by the control unit 16 of the exposure apparatus EX from each unit and device of the exposure apparatus EX, and is output to the information processing device 200 via the communication device 270. The control unit 16 may output one piece of lot data to the information processing device 200, or may collectively output multiple pieces of lot data to the information processing device 200. The control unit 16 may also store the lot data in a storage device, and output the lot data stored in the storage device to the information processing device 200. The control unit 16 may output, together with the lot data, information identifying the exposure apparatus EX and information identifying the processing conditions applied when the lot data was acquired to the information processing device 200.

[0040] 5, in S502, the accumulation unit 212 accumulates the lot data acquired by the acquisition unit 211 (S501) as accumulated data and stores it in the storage device 240. The accumulation unit 212 also acquires information that identifies the exposure tool EX and information that identifies the processing conditions that were applied when the lot data was acquired, and classifies and accumulates the lot data by exposure tool and by processing condition. In other words, the accumulation unit 212 accumulates the lot data acquired by the acquisition unit 211 by linking it to the same exposure tool and the same processing conditions.

[0041] Here, with reference to FIG. 7, the accumulated data in which lot data acquired from a plurality of exposure tools is accumulated will be described. FIG. 7 is a diagram showing an example of the accumulated data. The accumulated data has a hierarchical structure, and the lot data is classified and accumulated for each exposure tool and each processing condition. When exposure is performed for a plurality of lots under the same processing conditions in a certain exposure tool, a plurality of lot data are accumulated for the same processing conditions. In addition, the accumulated data includes statistical data (statistical values ​​of processing data) relating to the plurality of lot data accumulated for the same processing conditions. Note that, although the number of exposure tools is 4 and the number of processing conditions is 10 in FIG. 7, this is not limiting.

[0042] An example of the statistical data will be described. The statistical data includes, for each collected data included in the lot data, statistical values ​​such as the maximum value, minimum value, average value, median value, standard deviation, mode value, coefficient of variation, and variance of the collected data. The data included in the statistical data may be time-series data. Furthermore, the statistical data may be configured for each wafer and each shot area, similar to the lot data.

[0043] In S503, the analysis unit 213 finds the inter-tool difference between the multiple exposure tools for which the lot data was acquired. The analysis unit 213 finds the inter-tool difference in average and the inter-tool difference in variance based on the statistical values ​​accumulated in the accumulation unit 212 (S502). Here, it is assumed that the collected data has a distribution that follows the probability distribution of the average and variance of the accumulated statistical values. The collected data includes exposure tool factors and process condition factors, and if each factor follows a probability distribution, the collected data can be regarded as a simultaneous distribution of two variables, the exposure tool factors and the process condition factors.

[0044] The average of the joint distribution of two variables has the properties shown in the following formula 1. In formula 1, E is the average, and X and Y are random variables. By taking the difference in the average of the statistical data of two exposure tools that have common processing conditions, it is possible to find the inter-tool difference in the average of the exposure tool factors.

[0045]

number

[0046] Moreover, the variance of the joint distribution of two variables has the property shown in the following formula 2. In formula 2, V is the variance, Cov is the covariance, and X and Y are random variables. If the exposure tool factors and processing condition factors of the target collected data are limited to those that are independent of each other or have a sufficiently small covariance, the third term in formula 2 can be ignored. This makes it possible to find the inter-tool difference in variance, similar to the inter-tool difference in average.

[0047]

number

[0048] In S504, the prediction unit 214 predicts the probability distribution of lot data (processing data) for a combination of an exposure tool and processing conditions for which lot data has not been collected, based on the inter-tool difference obtained by the analysis unit 213 (S503). By adding or subtracting the inter-tool difference obtained in S503 to statistical data of processing conditions collected by only one of the two exposure tools, it is possible to predict the average and variance for a combination of an exposure tool and processing conditions for which lot data has not been collected. In the prediction, the average of the inter-tool differences obtained from a plurality of processing conditions may be used, or a weighted average of the inter-tool differences obtained from a plurality of processing conditions may be used. The weight of the weighted average may be determined based on collected data (e.g., the number of samples, the relationship of the inter-tool differences for each processing condition in other tools, etc.).

[0049] In addition, in this embodiment, a case has been described in which the probability distribution of processing data is predicted based on the inter-apparatus difference of the exposure apparatus, but this is not limited to this, and inter-apparatus differences of recipes and other processing apparatuses may also be used.

[0050] Thus, in S501 and S502, the first processing data, the second processing data, and the third processing data are acquired. The first processing data is processing data obtained by applying the first processing conditions to the first lithography apparatus and performing a lithography process on the substrate. The second processing data is processing data obtained by applying the second processing conditions, which are different from the first processing conditions, to the first lithography apparatus and performing a lithography process on the substrate. The third processing data is processing data obtained by applying the first processing conditions to the second lithography apparatus, which is different from the first lithography apparatus, and performing a lithography process on the substrate. In addition, in S503 and S504, a probability distribution of fourth processing data obtained by applying the second processing conditions to the second lithography apparatus and performing a lithography process is predicted based on the first processing data, the second processing data, and the third processing data. Note that the probability distribution represents the probability of the value that the fourth processing data can take. Based on the probability distribution of the fourth processing data predicted in this manner, a range for performing processing related to searching for a mark on a substrate when processing the substrate by applying second processing conditions to the second lithography apparatus is determined, as described below.

[0051] Hereinafter, a method for determining the range in which processing related to searching for marks provided on the wafer 4 processed by the exposure apparatus EX is performed based on statistical data (processing data) predicted by the information processing apparatus 200 will be described.

[0052] First, a case will be described where the detection range for pre-alignment (alignment processing related to positioning in the in-plane direction of the wafer 4) is determined as the range for performing processing related to the mark search.

[0053] In the exposure apparatus EX, two types of alignment, pre-alignment and fine alignment, are performed using alignment marks provided on the wafer 4. Pre-alignment involves finding the amount of misalignment of the wafer 4 sent from the wafer transport unit 12 to the wafer stage 6, and roughly aligning (positioning) the wafer 4 so that fine alignment can begin. Fine alignment involves measuring the position of the wafer 4 held by the wafer stage 6 with high accuracy, and precisely aligning (positioning) the wafer 4 so that the alignment error of the wafer 4 falls within an acceptable range.

[0054] Pre-alignment in the exposure apparatus EX will be described in detail. In this embodiment, in pre-alignment, alignment marks provided on the wafer 4 are detected using alignment scope 15. The image sensor of alignment scope 15 used in pre-alignment has a wide detection field of view, taking into consideration the amount of misalignment of the wafer 4 sent from the wafer transport unit 12 to the wafer stage 6. For example, when the size of the alignment mark (the area corresponding to the size) is 50 μm to 100 μm, the image sensor of alignment scope 15 has a detection field of view of approximately 200 μm to 400 μm.

[0055] Here, it is assumed that three times the standard deviation of the positional deviation of the wafer 4 sent from the wafer transport unit 12 to the wafer stage 6 is stable at about 25 μm. Then, it is assumed that the position of the alignment mark is obtained by performing a pattern matching process on the image information of all pixels of the imaging surface of the imaging element of the alignment scope 15 (i.e., the entire range of the image signal). In this case, most of the pixel information of the imaging surface of the imaging element of the alignment scope 15 is pixel information in which no alignment mark exists. Therefore, the pattern matching process is performed on image information corresponding to a wide detection range including an area in which no alignment mark exists. For this reason, time is wasted in obtaining the position of the alignment mark, which causes a decrease in the processing capacity, i.e., the throughput, of the exposure apparatus EX.

[0056] Therefore, in the detection signal corresponding to the alignment mark detected by the alignment scope 15, the range to be processed to obtain the position of the alignment mark (detection range) is limited (determined). When limiting this range, statistical data predicted by the information processing device 200 is used. In other words, based on the statistical data predicted by the information processing device 200, the range to be processed to obtain the position of the alignment mark in the detection signal when obtaining the position of the alignment mark is limited. This makes it possible to reduce the time required to obtain the position of the alignment mark.

[0057] A specific description will be given of limiting the range to be processed to obtain the position of the alignment mark, that is, the image processing range in which the pattern matching process is performed as image processing in this embodiment. FIG. 8 is a diagram showing the probability distribution of the detection position of the alignment mark predicted by the prediction unit 214. Referring to FIG. 8, it can be seen that three times (3σ) the standard deviation of the detection position of the alignment mark predicted by the prediction unit 214 is about 25 μm. In such a case, as shown in FIG. 9, the image processing range in which the pattern matching process should be performed in the image signal can be narrowed to about 100 μm×100 μm. In other words, the image processing range to be processed to obtain the position of the alignment mark to be detected can be narrowed. In this embodiment, the image processing range is determined based on the average value of the detection position of the alignment mark predicted by the prediction unit 214 and the size (dimension) of the alignment mark. Specifically, the range (100 μm × 100 μm) is determined as the image processing range by adding the range (25 μm) corresponding to the variation in the position of each alignment mark to the range (50 μm × 50 μm) corresponding to the size of the alignment mark. In this way, by limiting the image processing range in which the pattern matching process should be performed, the time required to obtain the position of the alignment mark can be reduced.

[0058] It is also possible to determine the range (detection range) to be processed in order to obtain the position of the alignment mark from the viewpoint of productivity.

[0059] In the exposure apparatus EX, if an alignment mark is not detected by the pattern matching process with the image processing range limited, a retry process is performed in which the image processing range is expanded and the pattern matching process is performed again. The expected number of retry processes can be calculated from the probability distribution of the predicted detection position of the alignment mark. The expected time required for the retry process is the product of the retry time per retry and the expected retry frequency. Since the effective time reduction is the time obtained by subtracting the expected time required for the retry process from the pattern matching process time reduced by limiting the image processing range, the image processing range is determined so as to maximize this reduction in time.

[0060] Furthermore, the retry process is not limited to the pattern matching process expanded to all pixels on the imaging surface of the imaging element of the alignment scope 15. For example, additional pattern matching process may be performed only on the expanded range, or the range (image processing range) may be expanded in stages.

[0061] In addition, in this embodiment, the image processing range in which the pattern matching process is performed as the image processing is limited, but the present invention is not limited to this. For example, instead of limiting the image processing range, the readout range in which the image signal is read out on the imaging surface of the imaging element of the alignment scope 15 may be limited (i.e., the image processing corresponding to the image processing range may be read out to the imaging element). In this case as well, the time required to obtain the position of the alignment mark can be reduced.

[0062] Next, a case will be described where the detection range for focus (focus control processing related to alignment in the height direction (Z direction) of the wafer 4) is determined as the range for performing processing related to the mark search.

[0063] In the alignment scope 15, regardless of whether it is an off-axis method or a TTL-AA method, it is necessary to adjust the focus (position in the Z direction) of the alignment mark with respect to the alignment scope 15 before detecting the alignment mark. Therefore, the detection signal output from the alignment scope 15 is monitored while driving the mark to be detected (the wafer 4 on which the mark is provided) in the Z direction. Then, the optimal focus position is obtained from an evaluation value such as contrast that indicates the relationship between the position of the mark in the Z direction and the detection signal (intensity) of the alignment scope 15, and the alignment mark is detected at the focus position. For example, a contrast curve that indicates the relationship between the position of the mark in the Z direction and the detection signal is obtained, and the peak position where the contrast is maximum is determined as the optimal focus position.

[0064] Since the mark is driven in the Z direction over a wide range in consideration of the variation between lots or wafers, the evaluation value is calculated for a range that is outside the optimal focus position. Therefore, time is wasted in obtaining the optimal focus position, which causes a decrease in the processing capacity, i.e., the throughput, of the exposure apparatus EX.

[0065] Therefore, the range (detection range) in which the evaluation value for obtaining the optimal focus position should be calculated is limited (determined). When limiting the range, statistical data predicted by the information processing device 200 is used. This makes it possible to reduce the time required to obtain the focus position.

[0066] FIG. 10 is a diagram showing the probability distribution of the focus position predicted by the prediction unit 214. Referring to FIG. 10, it can be seen that three times (3σ) the standard deviation of the focus position predicted by the prediction unit 214 is about 3 μm. In such a case, as shown in FIG. 11, the range in which the evaluation value should be calculated can be narrowed to about 8.4 μm. In this embodiment, the range in which the evaluation value should be calculated is determined based on the average value of the focus position predicted by the prediction unit 214 and the range (points) required to obtain the peak position of the contrast. Specifically, the range (8.4 μm) obtained by adding the range (3 μm) corresponding to the variation in the focus position to the range (0.6 μm×4) required to calculate the peak position is determined as the range in which the evaluation value should be calculated. In this way, the time required to obtain the focus position can be reduced by limiting the range in which the evaluation value should be calculated.

[0067] <Second embodiment> As the second embodiment, a method in which the information processing device 200 predicts the probability distribution of data related to lithography processing will be described. In this embodiment, a method in which the probability distribution of data related to lithography processing is predicted based on the inter-apparatus difference, as in the first embodiment, will be described. This embodiment differs from the first embodiment in that the exposure apparatus is not a different exposure apparatus, but the same exposure apparatus at a different period in the time series. The exposure apparatus may change its apparatus state from a specific point in the time series. The specific point includes replacement or adjustment of a unit of the exposure apparatus, and natural disasters such as earthquakes. When the apparatus state changes, the distribution of the processing data also changes, so that processing data acquired before the specific point cannot be used after the specific point (i.e., the processing data must be recollected).

[0068] In this embodiment, a method for predicting a probability distribution of process data related to lithography processes of the same apparatus before and after a specific point on a time series will be described. Note that it is assumed that collection and accumulation of process data for a period prior to the specific point has been completed.

[0069] In S501, the acquisition unit 211 acquires lot data from the exposure apparatus EX serving as the lithography apparatus 100. Furthermore, the acquisition unit 211 acquires, together with the lot data, information that identifies the exposure apparatus EX and information that identifies the processing conditions that were applied when the lot data was acquired.

[0070] In S502, the accumulation unit 212 accumulates the lot data acquired by the acquisition unit 211 (S501) as accumulated data, and stores it in the storage device 240. The accumulation unit 212 also acquires information specifying the exposure apparatus EX and information specifying the processing conditions applied when the lot data was acquired, and classifies and accumulates the lot data by exposure apparatus and by processing condition. In other words, the accumulation unit 212 accumulates the lot data acquired by the acquisition unit 211 in association with the same exposure apparatus and the same processing condition. The accumulation unit 212 also accumulates the lot data (statistical values) divided into those before a specific point in the time series and those after a specific point in the time series.

[0071] In S503, the analysis unit 213 finds the inter-tool difference for the same exposure tool from which the lot data was obtained. The analysis unit 213 finds the inter-tool difference in average and the inter-tool difference in variance before and after a specific point in the time series based on the statistical values ​​accumulated in the accumulation unit 212 (S502). Here, the collected data is assumed to have a distribution that follows the probability distribution of the average and variance of the accumulated statistical values. The collected data includes exposure tool factors and process condition factors, and if each factor follows a probability distribution, the collected data can be regarded as a simultaneous distribution of two variables, exposure tool factors and process condition factors.

[0072] As described above, the average of the joint distribution of two variables has the property shown in Equation 1. By taking the difference between the averages of the processing data before and after a specific point where the processing conditions are common, the inter-tool difference in the average of the exposure tool factors can be obtained.

[0073] Moreover, as described above, the variance of the joint distribution of two variables has the property shown in Equation 2. If the exposure tool factors and processing condition factors of the target collected data are limited to those that are independent of each other or have a sufficiently small covariance, the third term in Equation 2 can be ignored. This makes it possible to find the inter-tool difference in variance, just like the inter-tool difference in average.

[0074] In S504, the prediction unit 214 predicts the probability distribution of lot data (processing data) after a specific point in the time series based on the inter-apparatus difference obtained by the analysis unit 213 (S503). By adding or subtracting the inter-apparatus difference obtained in S503 to statistical data of the processing conditions collected in a period before the specific point, it is possible to predict the probability distribution of the processing data of the processing conditions in a period after the specific point that has not been collected.

[0075] Thus, in S501 and S502, the first processing data, the second processing data, and the third processing data are acquired. The first processing data is processing data obtained by performing lithography processing on a substrate by applying the first processing conditions to a lithography apparatus in the first apparatus state. The second processing data is second processing data obtained by performing lithography processing on a substrate by applying second processing conditions different from the first processing conditions to a lithography apparatus in the first apparatus state. The third processing data is third processing data obtained by performing lithography processing on a substrate by applying the first processing conditions to a lithography apparatus in the second apparatus state. Also, in S503 and S504, a probability distribution of fourth processing data obtained by performing lithography processing on a lithography apparatus in the second apparatus state by applying the second processing conditions is predicted based on the first processing data, the second processing data, and the third processing data. The probability distribution of the fourth processing data predicted in this manner is used to determine the range of processing related to searching for a mark on a substrate when processing the substrate by applying second processing conditions to a lithography apparatus in a second apparatus state.

[0076] <Third embodiment> As the third embodiment, a method in which the information processing device 200 predicts the probability distribution of data related to lithography processing will be described. In this embodiment, a method in which the information processing device 200 predicts the probability distribution of data related to lithography processing based on the inter-device difference will be described, as in the first embodiment. This embodiment differs from the first embodiment in that the combination of conditions is a combination of a pre-processing device and processing conditions. In the first embodiment, the combination of exposure devices and processing conditions was described, but the combination of conditions is not limited to two.

[0077] In S501, the acquisition unit 211 acquires lot data from the exposure apparatus EX serving as the lithography apparatus 100. In addition to the lot data, the acquisition unit 211 acquires information identifying the exposure apparatus EX, information identifying the processing conditions applied when the lot data was acquired, and information identifying the pre-processing apparatus that performed the pre-processing of the lot from which the lot data was acquired.

[0078] In S502, the accumulation unit 212 accumulates the lot data acquired by the acquisition unit 211 (S501) as accumulated data, and stores it in the storage device 240. The accumulation unit 212 acquires information identifying the exposure tool EX, information identifying the processing conditions applied when the lot data was acquired, and the pre-processing device that performed the pre-processing of the lot from which the lot data was acquired. The accumulation unit 212 then classifies and accumulates the lot data by exposure tool, processing condition, and pre-processing device.

[0079] Here, with reference to FIG. 12, the accumulated data in which lot data acquired from a plurality of exposure tools is accumulated will be described. FIG. 12 is a diagram showing an example of the accumulated data. The accumulated data has a hierarchical structure, and the lot data is classified and accumulated by exposure tool, processing condition, and pre-processing device. When exposure is performed under the same processing condition for a plurality of lots in a certain exposure tool, a plurality of lot data are accumulated for the same processing condition. In addition, the accumulated data includes statistical data (statistical values ​​of processing data) regarding the plurality of lot data accumulated for the same processing condition. Note that, although FIG. 12 shows that the number of exposure tools is 4, the number of processing conditions is 10, and the number of pre-processing devices is 4, the present invention is not limited to this.

[0080] In S503, the analysis unit 213 obtains inter-tool differences between the multiple exposure tools and pre-processing equipment for which lot data has been acquired. The analysis unit 213 obtains inter-tool differences in average and inter-tool differences in variance based on the statistical values ​​accumulated in the accumulation unit 212 (S502). Here, it is assumed that the collected data has a distribution that follows the probability distribution of the average and variance of the accumulated statistical values. The collected data includes exposure tool factors, process condition factors, and pre-processing equipment factors, and assuming that each factor follows a probability distribution, the collected data can be regarded as a simultaneous distribution of three variables: exposure tool factors, process condition factors, and pre-processing equipment factors.

[0081] The average of the joint distribution of two variables has the properties shown in the following formula 3. In formula 3, E is the average, and X, Y, and Z are random variables. By taking the difference in the average of the statistical data of two exposure tools and pre-processing tools that have common processing conditions, it is possible to find the inter-tool differences in the averages of the exposure tool factors and pre-processing tools.

[0082]

number

[0083] Moreover, the variance of the joint distribution of three variables has the properties shown in the following formula 4. In formula 4, V is the variance, Cov is the covariance, and X, Y, and Z are random variables. If the exposure tool factors, processing condition factors, and pre-processing equipment of the target collected data are limited to those that are independent of each other or have a sufficiently small covariance, the third term in formula 4 can be ignored. This makes it possible to find the inter-tool difference in variance, as well as the inter-tool difference in average.

[0084]

number

[0085] In S504, the prediction unit 214 predicts the probability distribution of lot data (processing data) for a combination of an exposure tool, processing conditions, and pre-processing equipment for which no lot data has been collected, based on the inter-tool difference determined by the analysis unit 213 (S503). The inter-tool difference determined in S503 is added to or subtracted from statistical data of the processing conditions and pre-processing equipment collected for only one of the two exposure tools. This makes it possible to predict the average and variance for a combination of an exposure tool, processing conditions, and pre-processing equipment for which no lot data has been collected.

[0086] The method for manufacturing an article in the embodiment of the present invention is suitable for manufacturing an article such as a device (semiconductor element, magnetic storage medium, liquid crystal display element, etc.). The manufacturing method includes a step of forming a pattern on a substrate (a step of exposing the substrate) using a lithography system LS (exposure apparatus EX), a step of processing the substrate on which the pattern has been formed (a step of developing the substrate), and a step of manufacturing an article from the processed substrate. The manufacturing method may also include other well-known steps (oxidation, film formation, deposition, doping, planarization, etching, resist stripping, dicing, bonding, packaging, etc.). The method for manufacturing an article in the present embodiment is advantageous in at least one of the performance, quality, productivity, and production cost of the article compared to the conventional methods.

[0087] The present invention can also be realized by a process in which a program for implementing one or more of the functions of the above-described embodiments is supplied to a system or device via a network or a storage medium, and one or more processors in a computer of the system or device read and execute the program. The present invention can also be realized by a circuit (e.g., ASIC) for implementing one or more of the functions.

[0088] The disclosure of this specification includes the following determination method, information processing device, and program.

[0089] (Item 1) 1. A method for determining a range for performing processing related to a search for a mark provided on a substrate processed by a lithography apparatus, comprising the steps of: a first step of acquiring first processing data obtained by performing a process on a substrate using a first lithography apparatus under first processing conditions, second processing data obtained by performing the process on the substrate using the first lithography apparatus under second processing conditions different from the first processing conditions, and third processing data obtained by performing the process on the substrate using a second lithography apparatus different from the first lithography apparatus under the first processing conditions; a second step of predicting a probability distribution of fourth processing data obtained by performing the processing under the second processing conditions in the second lithography apparatus based on the first processing data, the second processing data, and the third processing data; a third step of determining a range of processing related to searching for a mark provided on a substrate when processing the substrate by applying the second processing conditions to the second lithography apparatus based on the probability distribution of the fourth processing data predicted in the second step; The method of claim 1, further comprising:

[0090] (Item 2) 2. The method of claim 1, wherein the probability distribution represents a probability of a value that the fourth processed data can take.

[0091] (Item 3) 3. The method according to claim 1, wherein the process for searching for the mark includes an alignment process for aligning the substrate in an in-plane direction.

[0092] (Item 4) the alignment process includes a process of processing a detection signal of the mark to obtain a position of the mark; In the third step, a range of the detection signal to be processed for determining the position of the mark is determined as a range for performing processing related to searching for the mark. 4. The method according to item 3, characterized in that

[0093] (Item 5) 3. The method according to item 1 or 2, wherein the process relating to the search for the mark includes a focus control process relating to alignment in a height direction of the substrate.

[0094] (Item 6) the focus control process includes a process of obtaining a contrast of a detection signal of the mark while driving the substrate in a height direction, In the third step, a range in which a process related to a search for the mark is to be performed is determined, and an evaluation value for determining a position in a height direction of the substrate from the contrast is to be calculated. 6. The method according to item 5, characterized in that

[0095] (Item 7) 7. The method according to any one of items 1 to 6, wherein the second step includes predicting a mean or variance of a probability distribution of the fourth processed data.

[0096] (Item 8) 8. The method according to any one of items 1 to 7, wherein each of the first processing conditions and the second processing conditions includes a condition related to a pre-processing apparatus that performed pre-processing of a substrate.

[0097] (Item 9) 1. A method for determining a range for performing processing related to a search for a mark provided on a substrate processed by a lithography apparatus, comprising the steps of: a first step of acquiring first processing data obtained by performing a process on a substrate by applying first processing conditions to a lithography apparatus in a first apparatus state, second processing data obtained by performing the process on a substrate by applying second processing conditions different from the first processing conditions to the lithography apparatus in the first apparatus state, and third processing data obtained by performing the process on a substrate by applying the first processing conditions to the lithography apparatus in a second apparatus state different from the first apparatus state; a second step of predicting a probability distribution of fourth processing data obtained by performing the processing under the second processing conditions on the lithography apparatus in the second apparatus state based on the first processing data, the second processing data, and the third processing data; a third step of determining a range of processing related to searching for a mark provided on a substrate when processing the substrate by applying the second processing conditions to the lithography apparatus in the second apparatus state based on the probability distribution of the fourth processing data predicted in the second step; The method of claim 1, further comprising:

[0098] (Item 10) An information processing device, a processing unit that determines a range in which processing related to searching for a mark provided on a substrate to be processed by the lithography apparatus is to be performed; The processing unit includes: acquiring first processing data obtained by performing a process on a substrate using a first lithography apparatus under first processing conditions, second processing data obtained by performing the process on the substrate using the first lithography apparatus under second processing conditions different from the first processing conditions, and third processing data obtained by performing the process on the substrate using the first processing conditions in a second lithography apparatus different from the first lithography apparatus; predicting a probability distribution of fourth processing data obtained by performing the processing under the second processing conditions in the second lithography apparatus based on the first processing data, the second processing data, and the third processing data; determining a range for performing processing related to a search for a mark provided on a substrate when the second lithography apparatus applies the second processing conditions to the substrate and processes the substrate based on the probability distribution of the fourth processing data; 23. An information processing apparatus comprising:

[0099] (Item 11) 10. A program for causing a computer to execute the determination method according to any one of items 1 to 9.

[0100] The invention is not limited to the above-described embodiments, and various modifications and variations are possible without departing from the spirit and scope of the invention. Accordingly, the following claims are appended to apprise the public of the scope of the invention. [Explanation of symbols]

[0101] 100: Lithography apparatus 200: Information processing apparatus 211: Acquisition section 212: Storage section 213: Analysis section 214: Prediction section

Claims

1. 1. A method for determining a range for performing processing related to a search for a mark provided on a substrate processed by a lithography apparatus, comprising the steps of: a first step of acquiring first processing data obtained by performing a process on a substrate in a first lithography apparatus under first processing conditions, second processing data obtained by performing the process on the substrate in the first lithography apparatus under second processing conditions different from the first processing conditions, and third processing data obtained by performing the process on the substrate in a second lithography apparatus different from the first lithography apparatus under the first processing conditions; a second step of predicting a probability distribution of fourth processing data obtained by performing the processing under the second processing conditions in the second lithography apparatus based on the first processing data, the second processing data, and the third processing data; a third step of determining a range of processing related to searching for a mark provided on a substrate when processing the substrate by applying the second processing conditions to the second lithography apparatus based on the probability distribution of the fourth processing data predicted in the second step; The method of claim 1, further comprising:

2. 2. The method of claim 1, wherein the probability distribution represents probabilities of possible values ​​of the fourth processed data.

3. 2. The method according to claim 1, wherein the process for searching for the mark includes an alignment process for aligning the substrate in an in-plane direction.

4. the alignment process includes a process of processing a detection signal of the mark to obtain a position of the mark; In the third step, a range of the detection signal to be processed for determining the position of the mark is determined as a range for performing processing related to the search for the mark.

4. The method according to claim 3, wherein

5. 2. The method according to claim 1, wherein the process relating to the search for the mark includes a focus control process relating to alignment in a height direction of the substrate.

6. the focus control process includes a process of obtaining a contrast of a detection signal of the mark while driving the substrate in a height direction, In the third step, a range in which a process related to a search for the mark is to be performed is determined, and an evaluation value for determining a position in a height direction of the substrate from the contrast is to be calculated.

6. The method of claim 5.

7. 2. The method according to claim 1, wherein said second step comprises predicting a mean or a variance of a probability distribution of said fourth processed data.

8. The method according to claim 1 , wherein each of the first processing condition and the second processing condition includes a condition related to a pre-processing apparatus that performed pre-processing of the substrate.

9. 1. A method for determining a range for performing processing related to a search for a mark provided on a substrate processed by a lithography apparatus, comprising the steps of: a first step of acquiring first processing data obtained by performing a process on a substrate by applying first processing conditions to a lithography apparatus in a first apparatus state, second processing data obtained by performing the process on a substrate by applying second processing conditions different from the first processing conditions to the lithography apparatus in the first apparatus state, and third processing data obtained by performing the process on a substrate by applying the first processing conditions to the lithography apparatus in a second apparatus state different from the first apparatus state; a second step of predicting a probability distribution of fourth processing data obtained by performing the processing under the second processing conditions on the lithography apparatus in the second apparatus state based on the first processing data, the second processing data, and the third processing data; a third step of determining a range of processing related to searching for a mark provided on a substrate when processing the substrate by applying the second processing conditions to the lithography apparatus in the second apparatus state based on the probability distribution of the fourth processing data predicted in the second step; The method of claim 1, further comprising:

10. An information processing device, a processing unit that determines a range in which processing related to searching for a mark provided on a substrate to be processed by the lithography apparatus is to be performed; The processing unit includes: acquiring first processing data obtained by performing a process on a substrate using a first lithography apparatus under first processing conditions, second processing data obtained by performing the process on the substrate using the first lithography apparatus under second processing conditions different from the first processing conditions, and third processing data obtained by performing the process on the substrate using the first processing conditions in a second lithography apparatus different from the first lithography apparatus; predicting a probability distribution of fourth processing data obtained by performing the processing under the second processing conditions in the second lithography apparatus based on the first processing data, the second processing data, and the third processing data; determining a range for performing processing related to a search for a mark provided on the substrate when the second processing condition is applied to the second lithography apparatus to perform processing on the substrate based on the probability distribution of the fourth processing data; 23. An information processing apparatus comprising:

11. A program for causing a computer to execute the determination method according to any one of claims 1 to 9.

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