JP4984074B2 - Evaluation system and evaluation method - Google Patents

Description

  The present invention relates to an evaluation system and an evaluation method, and more specifically, photoelectrically detects a detection area including a detection target on an object to acquire a photoelectric conversion signal, and searches for the detection target using the photoelectric conversion signal. The present invention relates to an evaluation system and an evaluation method for evaluating processing.

  In recent years, in a manufacturing process of a device such as a semiconductor element, an exposure apparatus such as a step-and-repeat system or a step-and-scan system, a wafer prober, or a laser repair apparatus is used. In these apparatuses, each of a plurality of shot areas arranged on a substrate is set to a stationary coordinate system that defines the movement position of the substrate (orthogonal coordinate system that defines the position coordinates of the stage holding the substrate, ie, a stage coordinate system). It is necessary to align (align) very precisely with a predetermined reference point (for example, a processing point of various apparatuses).

  In particular, in an exposure apparatus, a circuit pattern (reticle pattern) of 10 layers or more is superimposed and transferred onto a substrate (hereinafter referred to as “wafer”). The above characteristics can be inconvenient. In such a case, the chip does not satisfy the desired characteristics, and in the worst case, the chip becomes a defective product, which reduces the yield. Therefore, in the exposure apparatus, an alignment mark is previously attached to each of a plurality of shot areas (areas on which the circuit pattern is transferred) on the wafer, and the alignment in the stage coordinate system that regulates the movement of the stage holding the wafer. Detect the position coordinates of the mark. Thereafter, wafer alignment is performed in which individual shot regions on the wafer are aligned with the reticle pattern based on the positional relationship between the mark position coordinates and a known reticle pattern (which is measured in advance). .

  In wafer alignment, waveform data representing a photoelectric conversion signal corresponding to an area on the wafer including the alignment mark is acquired, a portion corresponding to the alignment mark is searched in the acquired waveform data, and it is recognized that the alignment mark exists. The detected position is detected as the position coordinate of the alignment mark in the stage coordinate system.

  More specifically, by searching the waveform data, based on the characteristics of the alignment mark, several positions (candidate positions) that are likely to be mark positions are extracted from the waveform data, and a plurality of positions are extracted. When the template waveform of the mark is matched with each candidate position, the correlation between the template waveform and the waveform data corresponding to the template waveform is obtained, and whether or not the mark can be recognized based on the correlation Among the positions where it is determined that the mark can be recognized, the position having the highest correlation is detected as the mark position.

  On the other hand, when the waveform data is searched and the correlation is not more than a predetermined level at all candidate positions, a mark detection error is generated because the mark cannot be recognized. There are various reasons why marks cannot be recognized at all candidate positions. For example, of course, it may not be possible to recognize a mark due to noise components included in the waveform data, but the mark recognition process such as the design value of the mark width required for the mark recognition process is specified. It is also conceivable that the value of the processing parameter to be set is not set appropriately. In this case, if the processing parameter is reset to an appropriate value, the mark position can be searched without causing an unnecessary mark detection error.

  From this point of view, there is an increasing need for an environment that can analyze and evaluate the mark search process for the waveform data, identify the factors that cannot recognize the mark, and adjust the processing parameters. Yes. There are a large number of the above processing parameters, and even if they are adjusted rapidly, it is difficult to make the setting values of the processing parameters appropriate, and it takes time.

According to a first aspect of the present invention, a photoelectric conversion signal is obtained by photoelectrically detecting a detection region including a detection target that is one of a plurality of marks formed on an object, and the photoelectric conversion signal An evaluation system that evaluates the search processing of the detection target using the detection target, wherein the detection target is located at an arbitrary candidate position among a plurality of candidate positions in the detected region that are candidates for the position of the detection target. An acquisition device that acquires a detection result of the detection target using the photoelectric conversion signal, and a plurality of candidates based on specific information for specifying a candidate position of the detection target A specifying device that specifies at least one candidate position from among the positions; based on the detection result acquired by the acquiring device on the assumption that the detection target is located at the candidate position specified by the specifying device; And The object except a mark to be detected contained in the experience on the already obtained information or design information, and the detection area of the detection target; evaluation device and for evaluating the detection target of the search processing using a photoelectric conversion signal And an estimation device that estimates specific information for specifying the candidate position of the detection target based on a processing result of statistical processing using position information of the other mark above .

  According to this, since the acquisition device for acquiring the detection result of the detection target at any at least one candidate position is provided, by specifying at least one candidate position from among the plurality of candidate positions by the specifying device, It is possible to acquire the detection result of the detection target at the identified candidate position and evaluate the detection target search process using the photoelectric conversion signal based on the acquired detection result.

According to a second aspect of the present invention, a photoelectric conversion signal is obtained by photoelectrically detecting a detection area including a detection target that is one of a plurality of marks formed on an object, and the photoelectric conversion signal An evaluation method for evaluating the detection target search process using a detection signal using the photoelectric conversion signal from a plurality of candidate positions in the detected region that are candidates for the position of the detection target. A specifying step of specifying at least one candidate position from which the detection result of the object is acquired; an acquisition step of acquiring the detection result of the detection target using the photoelectric conversion signal at the candidate position specified in the specifying step; ; on the basis of the detection result acquired in the acquisition step, evaluation process and evaluating the search process of the detection target using the photoelectric conversion signal; on previously obtained by being experienced information or detection target setting Specific information for specifying the candidate position is estimated based on information and a processing result of statistical processing using position information of other marks on the object excluding a mark as a detection target included in the detection area. And an estimation step .

  According to this, in the specifying step, at least one candidate position from which the detection result of the detection target is acquired is specified based on the specifying information for specifying the candidate position of the detection target on the object. The detection result of the detection target using a photoelectric conversion signal when the detection target is assumed to be located at the specified candidate position is acquired. If it does in this way, the detection result of the detection object in the arbitrary at least one candidate position specified based on specific information will be acquired, and the photoelectric conversion signal was used based on the acquired detection result in the evaluation process. It becomes possible to evaluate the search process of the detection target.

1 is a view showing a schematic configuration of an exposure apparatus 100 according to a first embodiment of the present invention. FIG. 2A is a diagram illustrating an example of a wafer shot map, and FIG. 2B is a diagram illustrating an example of a wafer mark attached to a shot region. It is a figure which shows an example of the alignment correction amount and the residual in each sample shot area | region in a certain wafer. 4A is a diagram illustrating an example of raw waveform data obtained from the imaging result of the alignment system AS, and FIG. 4B is a state diagram in which the starting point of the mark template is shifted in units of edge candidates. FIG. 4C is a diagram schematically showing a buffer memory for storing a result of mark recognition performed by shifting the starting point of the mark template in units of edge candidates. It is a figure which shows the relationship between an error code and an error factor. It is a figure which shows an example of the mark detection result displayed on a display. It is a figure which shows an example of a waveform display window. It is a figure which shows examples, such as a waveform display window and a parameter setting window. It is a flowchart which shows the process of the simulation of the mark recognition process in the 1st Embodiment of this invention. FIG. 10A shows a method (part 1) for specifying an edge candidate position, and FIG. 10B shows a method (part 2) for specifying an edge candidate position. FIG. 11A is a diagram illustrating an example of an image display of the alignment correction amount, and FIG. 11B is a diagram illustrating a decomposition example of the vector of the alignment correction amount. FIG. 12A is a diagram illustrating an example (part 1) of the image display of the residual of alignment, and FIG. 12B is a diagram illustrating an example of decomposition of the alignment residual vector. FIG. 13A is a diagram showing an example (part 2) of the image display of the residual of alignment, and FIG. 13B is a diagram showing an example of decomposition of the vector of the residual of alignment. It is a figure which shows the other example of a waveform display window. It is a flowchart which shows the process of the simulation of the mark recognition process in the 2nd Embodiment of this invention. It is a figure for demonstrating the search process of the mark in two-dimensional image data.

<< First Embodiment >>
A first embodiment of the present invention will be described with reference to FIGS. FIG. 1 shows a schematic configuration of an exposure apparatus 100 that can suitably execute the evaluation method according to the first embodiment of the present invention. The exposure apparatus 100 includes an illumination system 10, a reticle stage RST that holds a reticle R, a projection optical system PL, a wafer stage WST on which a wafer W is mounted, a main controller 20 that performs overall control of the entire apparatus, and the like. The exposure apparatus 100 is a scanning exposure apparatus.

  The illumination system 10 includes a light source, an illuminance uniformizing optical system including an optical integrator, a relay, as disclosed in, for example, Japanese Patent Application Laid-Open No. 2001-313250 (corresponding US Patent Application Publication No. 2003/0025890). It includes a lens, a variable ND filter, a reticle blind (also called a masking blade), a dichroic mirror, and the like (all not shown). To the extent permitted by national legislation in the designated country or selected selected country designated in this international application, the disclosure in the above publication and corresponding US patent application publication is incorporated herein by reference. The illumination system 10 illuminates a slit-shaped illumination area defined by a reticle blind on a reticle R on which a circuit pattern or the like is drawn with a substantially uniform illuminance by illumination light IL.

Here, as the illumination light IL, far ultraviolet light such as KrF excimer laser light (wavelength 248 nm), vacuum ultraviolet light such as ArF excimer laser light (wavelength 193 nm), F ₂ laser light (wavelength 157 nm), or the like is used. . As the illumination light IL, it is also possible to use an ultraviolet bright line (g-line, i-line, etc.) from an ultra-high pressure mercury lamp. As the optical integrator, a fly-eye lens, a rod integrator (an internal reflection type integrator), a diffractive optical element, or the like is used.

  On reticle stage RST, reticle R is fixed, for example, by vacuum suction. Reticle stage RST can be finely driven in an XY plane perpendicular to the optical axis of illumination system 10 (corresponding to optical axis AX of projection optical system PL described later) by a reticle stage drive unit (not shown) including a linear motor, for example. In addition, it can be driven at a scanning speed designated in a predetermined scanning direction (here, the Y-axis direction which is the horizontal direction in FIG. 1).

  The position of the reticle stage RST in the stage moving surface is always detected by a reticle laser interferometer (hereinafter referred to as “reticle interferometer”) 16 via a movable mirror 15 with a resolution of about 0.5 to 1 nm, for example. Yes. Position information of reticle stage RST from reticle interferometer 16 is supplied to stage controller 19 and main controller 20 via this. In response to an instruction from main controller 20, stage controller 19 controls driving of reticle stage RST via a reticle stage drive unit (not shown) based on position information of reticle stage RST. A pair of reticle alignment systems (not shown) is disposed above the reticle R. Since the configuration of the pair of reticle alignment systems is disclosed in, for example, Japanese Patent Laid-Open No. 7-176468 and the corresponding US Pat. No. 5,646,413, detailed description thereof is omitted here. To the extent permitted by national legislation in the designated or selected countries designated in this international application, the disclosures in the above publications and corresponding US patents are incorporated herein by reference.

  The projection optical system PL is disposed below the reticle stage RST in FIG. 1, and the direction of the optical axis AX is the Z-axis direction. As projection optical system PL, for example, a double telecentric reduction system is used. The projection magnification of the projection optical system PL is, for example, 1/4, 1/5, or 1/6. For this reason, when the reticle R is illuminated by the illumination light IL from the illumination system 10, the illumination light irradiation region (the above-described illumination region) is irradiated by the illumination light IL that has passed through the reticle R via the projection optical system PL. A reduced image (partial image) of the circuit pattern of the inner reticle R is formed on the wafer W whose surface is coated with a resist (photosensitive agent).

  Wafer stage WST is arranged on a base (not shown) below projection optical system PL in FIG. 1, and is, for example, a wafer stage driving unit 24 including a linear motor and the like in the Y-axis direction and the X-axis direction ( Driven with a predetermined stroke in the direction orthogonal to the paper surface in FIG. 1, the Z-axis direction, the θx direction (the rotation direction around the X axis), the θy direction (the rotation direction around the Y axis), and the θz direction (the rotation around the Z axis) Direction). Wafer holder 25 is placed on wafer stage WST, and wafer W is fixed on wafer holder 25 by, for example, vacuum suction.

  The position of wafer stage WST in the XY plane is always detected by a wafer interferometer 18 with a resolution of, for example, about 0.5 to 1 nm via a moving mirror 17 provided on the upper surface thereof. That is, in the first embodiment, a stationary coordinate system (orthogonal coordinate system) that defines the movement position of wafer stage WST is defined by the measurement axes of the Y interferometer and X interferometer of wafer interferometer 18. . Hereinafter, this stationary coordinate system is also referred to as a stage coordinate system. Position information (or speed information) of wafer stage WST on the stage coordinate system is supplied to stage controller 19 and main controller 20 via this. In accordance with an instruction from main controller 20, stage controller 19 controls wafer stage WST via wafer stage drive unit 24 based on the position information (or speed information) of wafer stage WST.

  A reference mark plate FM is fixed in the vicinity of wafer W on wafer stage WST. The surface of the reference mark plate FM is set to the same height as the surface of the wafer W, and a reference mark for baseline measurement of the alignment system, a reference mark for reticle alignment, and other reference marks to be described later are formed on this surface. Has been.

  Further, an off-axis alignment system AS is fixed to the side surface of the projection optical system PL. The alignment system AS has two types of alignment sensors, an LSA (Laser Step Alignment) system and an FIA (Field Image Alignment) system, and X and Y2 of the reference mark on the reference mark plate FM and the alignment mark on the wafer. It is possible to perform position measurement in the dimensional direction. Here, the LSA system is the most versatile sensor that irradiates a mark with laser light and measures the mark position using diffracted and scattered light. The FIA system is a sensor that measures a mark position by illuminating a mark with broadband light such as a halogen lamp and performing image processing on the mark image. Since such an alignment system AS is disclosed in, for example, Japanese Patent Laid-Open No. 7-321028, detailed description thereof is omitted. As long as the national laws of the designated country designated in this international application or the selected selected country permit, the disclosure in the above publication is incorporated as a part of the description of this specification.

  The exposure apparatus 100 further supplies an imaging light beam for forming a plurality of slit images toward the best imaging plane of the projection optical system PL from an oblique direction (not shown) that is oblique to the optical axis AX direction. An oblique incidence type multi-point focus detection system comprising a system and a light receiving optical system (not shown) that receives each reflected light beam of the imaging light beam on the surface of the wafer W through a slit is provided as a projection optical system PL. It is being fixed to the support part (illustration omitted) to support. As this multipoint focus detection system, for example, one having the same configuration as that disclosed in Japanese Patent Laid-Open No. 6-283403 (corresponding US Pat. No. 5,448,332) is used, and stage control is used. The apparatus 19 minutely drives the wafer stage WST in the Z-axis direction and the tilt direction (θx direction and θy direction) via the wafer stage drive unit 24 based on the wafer position information from the multipoint focus detection system, and the wafer W Focus leveling control is performed. To the extent permitted by national legislation in the designated or selected countries designated in this international application, the disclosures in the above publications and corresponding US patents are incorporated herein by reference.

  The stage controller 19 performs position control operations for the wafer stage WST and the reticle stage RST under the instruction of the main controller 20.

  The main control device 20 includes a microcomputer or a workstation, and controls each part of the device in an integrated manner. The main control device 20 includes a CPU for executing various programs for controlling the operation of the exposure apparatus, and an internal memory for storing the programs and various data (all not shown). The main controller 20 is connected to a storage device 21 so that data can be read from and written to the storage device 21. Further, main controller 20 can transmit and receive data to and from personal computer (PC) 130 via a communication network such as a LAN (Local Area Network).

  The PC 130 includes a computer main body (hereinafter abbreviated as “PC main body”) 130P and a display 130D. The PC 130 provides an operator with a predetermined operating system (hereinafter abbreviated as “OS”) that provides an environment of a graphic user interface (hereinafter abbreviated as “GUI”) that can be operated by a pointing device such as a mouse. It is configured using a personal computer that operates in (described below).

  The PC main body 130P includes a microprocessor and memory (not shown), a keyboard interface (keyboard controller) for connecting a keyboard 130K and a mouse 130M, a video interface for connecting a display 130D, a serial interface, a hard disk, and an exposure apparatus. The PC main body 130 is connected with a keyboard 130K, a mouse 130M, and a display 130D as input devices. Yes. In addition, application software (hereinafter abbreviated as “application”) for analyzing and evaluating a mark recognition process described later, which is performed by the exposure apparatus 100, is installed in the PC main body 130P. This application transmits / receives a data file to / from the main controller 20 constituting at least a part of the exposure apparatus 100 via a communication network, for example, under FTP (File Transfer Protocol).

  The PC 130 does not have to be a personal computer, and may be a dedicated board that implements the man-machine interface of the exposure apparatus 100.

<Exposure operation>
Next, a series of exposure operations in the exposure apparatus 100 will be described. This exposure operation is performed under the control of the main controller 20. As a prerequisite, the wafer W subject to exposure is already completed the exposure of one or more layers, it is assumed that a plurality of shot areas SA _p is the formation wafer W as shown in FIG. 2 (A).

  First, a reticle R on which a circuit pattern to be transferred is formed is loaded onto a reticle stage RST by a reticle loader (not shown). Then, main controller 20 drives and controls wafer stage WST via stage controller 19 and wafer stage drive unit 24, and uses a detection system such as a reticle alignment detection system and alignment system AS (not shown) to perform reticle alignment. After performing preparatory work such as baseline measurement, a wafer loader (not shown) is used to load a wafer W to be exposed onto wafer stage WST.

(Search alignment)
Next, main controller 20 performs search alignment using alignment system AS. As shown in FIG. 2A, at least two locations on the wafer W are provided with marks that can be observed at a low magnification, so-called search alignment marks (hereinafter abbreviated as “search marks”) SYM and SθM. It has been. Main controller 20 sequentially positions each search mark within the detection field of alignment system AS, so that target position of wafer stage WST (target position based on the design position coordinates of search marks SYM and SθM) is stage controller 19. To give. The stage controller 19 sequentially positions the wafer stage WST via the wafer stage drive unit 24 in accordance with the target position. At each positioning, main controller 20 causes alignment system AS to detect a photoelectric conversion signal corresponding to a region including one of search marks SYM and SθM, and obtains the photoelectric conversion signal. Main controller 20 searches for the mark in the waveform data using the photoelectric conversion signal, and calculates position information of search marks SYM and SθM based on the search result. Search mark SYM, EsushitaM, when shot area SA _p is formed transfer, therefore the positional relationship between the shot area SA _p is mark transferred formed in a state of a fixed sequence of the shot areas SA _p Are formed in accordance with an array coordinate system (αβ coordinate system in FIG. 2A). The main controller 20, search mark SYM, calculated from the detected position of EsushitaM, rotation component of the array coordinate system of the wafer in the shot area SA _p with respect to the stage coordinate system, an offset component.

Next, main controller 20 performs wafer alignment. As shown in FIG. 2A, among the plurality of shot areas SA _p already formed on the wafer W, a round mark is displayed at the center in the eight shot areas SA _p . This mark indicates that the shot area SA _p is a sample shot area whose position coordinates are measured by this wafer alignment. The main controller 20 is attached to the sample shot SA _p according to the arrangement coordinate system whose components are obtained by search alignment, and a fine alignment mark (hereinafter abbreviated as a wafer mark) provided corresponding to the center C _p. A target position of wafer stage WST is given to stage controller 19 so that MX _p and MY _p are sequentially positioned within the detection visual field of alignment system AS. The stage control device 19 sequentially positions the wafer stage WST via the wafer stage driving device 24 according to the target position. Each time this positioning is performed, main controller 20 acquires, in alignment system AS, the photoelectric conversion signal detected so as to correspond to the area on the wafer including wafer marks MX _p and MY _p , and based on the photoelectric conversion signal. Using the waveform data, a mark search process for searching for the wafer marks MX _p and MY _p is performed, and the position information of the wafer marks MX _p and MY _p is detected based on the search result.

Wafer marks MX _p, the position of the MY _p is the same as the XY position of the center C _p of sample shot areas SA _p corresponding to the wafer mark MX _p, MY _p. That is, if the position information of the wafer marks MX _p and MY _p is detected, the position information of the sample shot area SA _p is measured in this wafer alignment. In FIG. 3, the measured position of the wafer mark measured in this way, that is, the XY position of the sample shot area SA _p is indicated by x on the image map of the shot area of the wafer W.

Next, main controller 20 uses, for example, the calculated position information of sample shot area SA _p to disclose, for example, Japanese Patent Application Laid-Open No. 61-44429 and US Pat. No. 4,780,617 corresponding thereto. The statistical calculation using the least square method disclosed in the above is executed, and parameters such as a scaling component, an offset component, and an orthogonality component of the shot region array in the stage coordinate system are calculated. To the extent permitted by national legislation in the designated or selected countries designated in this international application, the disclosures in the above publications and corresponding US patents are incorporated herein by reference. An arithmetic expression defined by the parameters is a so-called EGA model expression. In this EGA model formula, when a design position coordinate of the center C _p of the shot area SA _p is substituted, a correction amount (alignment correction amount) in the X-axis and Y-axis directions of the center position coordinate is obtained as an output. It is a model formula. When performing superposition exposure, main controller 20 substitutes the design position coordinates of each shot area on wafer W into this EGA model formula to calculate the alignment correction amount in that shot area, calculating a corrected position coordinates in the alignment correction as the reference position of the overlay exposure for the shot area SA _p.

In FIG. 3, the alignment correction amount in the sample shot area SA _p on the image map of the shot area SA _p of the wafer W is displayed as a vector. Origin of this vector indicates the location on the design of the shot area SA _p, the end point indicates the reference position after correction. As shown in FIG. 3, the tip of the alignment correction amount vector and the measured position of the sample shot area SA _p substantially coincide with each other, but a slight deviation actually occurs. This is because the EGA model formula for obtaining the alignment correction amount is a model formula based only on linear components such as scaling and rotation components, and using a statistical method using the measured position coordinates of the sample shot area SA _p. This is because it is specified. The difference between the overlay reference position corrected by the alignment correction amount and the actually measured position coordinates of the sample shot area SA _p is hereinafter referred to as a residual.

  When the wafer alignment is finished, the alignment correction amount of each sample shot region, the corrected position data of the sample shot region calculated based on the alignment correction amount, and the residual data thereof are: Each is stored in the storage device 21.

  After the wafer alignment is completed, a step-and-scan exposure operation is performed as follows.

In this exposure operation, first, the main controller 20 makes the XY position of the wafer W the first shot based on the wafer alignment result and the baseline measurement result via the stage controller 19 and the wafer stage drive unit 24. Wafer stage WST is moved so that it becomes the scanning start position for exposure of the region (first shot), and at the same time, the position of reticle R starts scanning via stage controller 19 and a reticle stage drive unit (not shown). The reticle stage RST is moved so as to be in the position. Then, in a state of being synchronously moving the reticle stage RST and wafer stage WST by the position control of the stage controller 19, by irradiating the illumination light IL by the illumination system 10, the scanning exposure for the first shot area SA _p Done.

When the transfer of the reticle pattern for the first shot area SA _p is completed, the wafer stage WST, and at the same time moved to the scanning start position of the second shot area, the reticle stage RST, a scan start position for the second shot area Then, scanning exposure is performed in the same manner as in the case of the first shot area. In this manner, the movement of wafer stage WST to the scanning start position of the next shot area, the movement of reticle stage RST to the scanning start position for the next shot area, and scanning exposure are sequentially repeated, and wafer W A pattern having the number of shots necessary for the transfer is transferred.

As described above, in a series of exposure operations on the wafer W, search alignment and wafer alignment are performed. In each alignment, the alignment system AS detects the photoelectric conversion signal corresponding to the area on the wafer W including the search marks SYM and SθM and the fine alignment marks MX _p and MY _{p of} the sample shot area SA _p , and the photoelectric conversion is performed. A mark is searched in the waveform data corresponding to the signal (mark search process), and the position information of the mark is calculated based on the search result. Hereinafter, the mark search process will be specifically described.

  As described above, in the alignment system AS, two sensors of the FIA method and the LSA method are prepared. Regardless of which sensor is selected, a photoelectric conversion signal corresponding to a region including a mark detected by the sensor can be acquired. Here, it is assumed that an FIA sensor is selected. As will be described later, the photoelectric conversion signal becomes one-dimensional signal waveform data in the X-axis direction or the Y-axis direction. Main controller 20 searches the waveform data using a predetermined search algorithm, and detects position information of each mark based on the search result.

  Here, an example of the search algorithm will be described. Here, a line and space (L / S) mark arranged along the Y-axis direction is searched based on the one-dimensional waveform data, and the Y position of the mark is calculated based on the search result. The case will be described.

  The photoelectric conversion signal detected by the FIA sensor is an imaging result (imaging data) of an area including each L / S mark on the wafer W. In this search algorithm, first, with respect to imaging data sent from the alignment system AS, white noise is canceled by obtaining an average of intensity distributions on a plurality of scanning lines in the Y-axis direction, and then waveform smoothing (smoothing processing) ) To obtain a one-dimensional average signal intensity distribution in the Y-axis direction. This signal intensity distribution becomes signal waveform data for searching for a mark. FIG. 4A shows a waveform data function p (Y) as an example of the waveform data.

(Differentiation of waveform data)
Main controller 20 calculates a differential waveform of the signal intensity distribution. FIG. 4B shows a differential waveform p ′ (Y) of the waveform data function p (Y) of FIG.

(Extract edge candidate positions)
As shown in FIG. 4B, in this differential waveform p ′ (Y), several peaks that appear to correspond to edges that are boundaries between the line pattern of the L / S mark and the space portion appear. Become. Main controller 20 extracts a position having a peak that is greater than or equal to the contrast limit value in this differential waveform as a candidate position that is a candidate for the position where the pattern edge (ie, edge) is present in the L / S mark. . In FIG. 4B, a plurality of candidate positions are indicated by vertical broken lines.

(Mark recognition processing)
Next, for each of the plurality of edge candidate positions extracted as described above, a process for determining whether or not the L / S mark can be recognized, that is, a so-called mark recognition process is performed. Hereinafter, this mark recognition process will be described.

  In this mark recognition processing, mark recognition is performed using a mark template waveform based on L / S mark design information. Specifically, as indicated by a thick arrow in FIG. 4B, the mark template waveform starts with the edge at the −Y end of the mark template waveform as a starting point and matches the starting point with a specific edge candidate. Whether or not a mark can be recognized at that position by examining how much correlation exists between the waveform data and the portion of the waveform data corresponding to that waveform (ie, the portion within the frame of the mark template waveform) Judging.

  First, the total number of edges in the portion within the mark template waveform frame is obtained, and it is determined whether or not the number of edges is smaller than the set number of edges. If this determination is affirmed, it is considered that the mark could not be recognized, and errorcode01 is set as an error code indicating the error cause. This error code will be described later.

  Since the mark is considered to exist near the center of the waveform data, a measurement range (processing range) is defined, and the range in which the mark recognition process is performed is limited to some extent. In FIG. 4B, the boundary of the measurement range is indicated by a vertical double line. Therefore, in the first embodiment, it is next determined whether or not the edge in the mark template frame protrudes from the processing range. If this determination is affirmative, it is considered that the mark could not be recognized, and errorcode02 is set as an error code.

  Further, it is determined whether or not the edge strength in the mark template frame is equal to or lower than a predetermined strength. If this determination is affirmative, it is considered that the mark could not be recognized, and errorcode03 is set as the error code.

  Further, it is determined whether or not the directions of the edge strengths in the mark template frame are alternately arranged. If this determination is affirmative, it is considered that the mark could not be recognized, and errorcode04 is set as an error code.

  If any of the above determinations are negative, the edge candidate position corresponding to each edge position of the mark template can be determined, so that a score indicating the recognition degree of the mark is calculated based on the determined edge candidate position. I do.

  This score is an index value indicating how accurately the waveform data in the frame of the mark template reproduces the feature of the mark. In the first embodiment, the amount of deviation between the design feature of the mark and the feature of the actual waveform data is obtained as a feature amount, and the score is calculated based on the feature amount. Features of the L / S mark include, for example, the width of each line pattern (mark width), the interval between line patterns (mark interval), the edge shape of the boundary with the space portion of each line pattern, etc. Then, the feature amount corresponding to each of these features is calculated.

  First, the sum of errors between the design value (interval of the template line pattern) of each line pattern of the L / S mark and the interval of each line pattern assumed by the edge candidate position (this is the feature amount 1). ) Is calculated. Next, the sum of errors between the design value of the width of each line pattern of the L / S mark (the width of the line pattern of the template) and the width of each line pattern assumed by the edge candidate position (this is the feature amount 2 Is calculated). Then, a feature amount relating to “uniformity of edge strength” is obtained by calculating a standard deviation of peak values (this is referred to as feature amount 3). Then, a weighted sum of these feature amounts is obtained. This value is used as the score of the combination of edge candidate positions.

  Next, the calculated score is compared with a preset threshold value, and if the score is better than the threshold value, it is considered that the mark has been recognized. Otherwise, the mark is recognized. Is considered to have failed.

  Here, if it is considered that the score is not better than the threshold value and the mark cannot be recognized, the factor is analyzed.

  First, it is determined whether or not the feature amount 1 exceeds a preset allowable value. If this determination is affirmed, it is considered that the factor that the mark could not be recognized is that the mark interval error has exceeded the allowable value, and errorcode05 is set as the error code.

  Next, it is determined whether or not the feature amount 2 exceeds a preset allowable value. If this determination is affirmed, it is considered that the factor that the mark could not be recognized is that the mark width error exceeds the allowable value, and errorcode06 is set as the error code.

  In addition, the balance of the mark edge interval exceeds a preset allowable value, or the balance of the mark edge intensity exceeds a preset allowable value based on the feature amount 3, or between line marks. Judgment is also made as to whether the variation in edge strength exceeds the preset allowable value, or whether the number of detected edges of each line pattern is less than the preset number of preset edges. Then, the factor that could not recognize the mark is identified, and the identified factor code (errorcode07 to 0A) is set as the error code of each error factor.

  In this way, error factors are subdivided to some extent by analysis and encoded. FIG. 5 shows a relationship table between the error code and the error factor.

  As described above, in the mark recognition processing performed by aligning the starting point of the mark template with one of the edge candidate positions, if the score value based on the feature of the mark calculated in the middle is better than the threshold value, If the recognition is successful, but there are no edges to the extent that the score can be calculated, or if the waveform features in the mark template frame deviate significantly from the mark features A mark detection error is generated as a failure. Such a mark recognition result, that is, a score or an error code is stored in the buffer memory b [0].

  Next, as shown in FIG. 4B, the mark recognition process described above is performed again in a state where the starting point of the mark template is shifted to the second edge candidate position, and the recognition result (score, error code) is obtained. Store in the buffer memory b [1]. Thereafter, in this way, the mark template using the mark template is performed each time while shifting the starting point of the mark template one by one in the + Y direction, and the recognition result is stored in the buffer memory b [i] (i = 2). 3,... Sequentially. FIG. 4B schematically shows how the mark template is shifted in the + Y direction, and FIG. 4C shows mark recognition processing stored in each buffer memory b [i]. An example of a recognition result (score, error code) is shown. Data stored in each buffer memory b [i] (buffer memories b [0] to b [23] in FIG. 4C) is stored in the storage device 21.

  Main controller 20 performs mark recognition processing at each edge candidate position using the above-described mark recognition algorithm, and obtains a mark recognition result at each edge candidate position. Then, the edge candidate position having the best score is determined from the plurality of edge candidate positions, and the center position of the mark having a predetermined offset is calculated as the mark position from the edge candidate position. In the first embodiment, since the left edge of the mark template waveform is the starting point of mark recognition, the predetermined offset is a design distance between the left edge and the center of the mark.

  The main controller 20 displays the waveform data, the score, the position information of the search mark when the mark detection is successful, the error code information when the mark detection fails, the lot number to which the wafer belongs, the wafer Number, recognition parameters used for mark recognition processing in alignment system AS (FIA method or LSA method, design values such as line pattern width and interval, algorithm number, processing parameter for each algorithm number), etc. are written. The prepared data file is created as an alignment history data file, and the alignment history data file is stored in the storage device 21. This completes the mark search process.

Main controller 20 performs search alignment or wafer alignment based on the position information of search marks SYM and SθM and wafer marks MX _p and MY _p obtained by using the mark search process as described above. At this time, if a mark cannot be recognized at all edge candidate positions, a mark detection error is generated.

  Note that the order of error checking in the above-described mark recognition algorithm is not limited to that described above, and can be changed as appropriate.

(Evaluation of mark recognition processing)
As described above, in the first embodiment, in one-dimensional waveform data, a mark is searched by performing mark recognition processing at a plurality of edge candidate positions, and the position coordinates of the mark detected as a result of the search Based on the above, the reference position for overlay exposure is obtained. Therefore, in order to perform highly accurate overlay exposure, it is essential that marks can be properly recognized when searching for marks. For this reason, there is a mechanism that can evaluate mark recognition processing. It is desirable that it is constructed. Therefore, in the first embodiment, an application for evaluating the mark recognition process can operate on the PC 130. Below, this application is demonstrated.

  As a premise, it is assumed that the application for evaluating mark recognition processing in the exposure apparatus 100 has already been started in the PC 130. In this state, when the operator designates the product name, lot name, wafer number, and layer number via the mouse 130M or the keyboard 130K, the application controls the exposure apparatus 100 as an FTP (file transfer protocol) client. A connection request is transmitted to the apparatus 20 (FTP server). When the connection request is permitted, the application next transmits a directory display request to the main control device 20. In response to this request, main controller 20 reads out alignment history data relating to the designated wafer layer from storage device 21 and sends it to PC 130. The application receives the alignment history data, and causes the display 130D to display a window for displaying the image display of the shot map of the designated wafer and the alignment history data in the window displayed on the display 130D. FIG. 6 shows an example of this window display.

On the screen shown in FIG. 6, an image diagram of the shot map on the wafer W designated by the operator is displayed, and in the image diagram of the shot area SA _p of the wafer W, matrix cells are displayed. The cell shows the respective shot areas SA _p formed on the wafer. Some cells display a mark, but the cell displaying the mark indicates a sample shot area.

In more detail, as a mark of each cell, a round mark, a triangle (upward convex triangle) mark, an inverted triangle (downward convex triangle) mark, and a square mark are displayed. . The round mark indicates that the shot area SA _p is a sample shot area in which no mark detection error has occurred for both the wafer marks MX _p and MY _p and the mark position information has been successfully detected. . The triangular mark indicates that the shot area SA _p is a sample shot area in which the detection of the wafer mark MX _p has succeeded but the detection of the wafer mark MY _p has failed and a mark detection error has occurred. Yes. The inverted triangle mark indicates that the shot area SA _p is a sample shot area in which the detection of the wafer mark MY _p has succeeded and the detection of the wafer mark MX _p has failed and a mark detection error has occurred. Yes. The square mark indicates that the shot area SA _p is a sample shot area where a mark detection error has occurred for both the wafer marks MX _p and MY _p . Although not shown in FIG. 6, it is assumed that marks corresponding to the search marks SYM and SθM are displayed in addition to the wafer marks MX _p and MY _p .

That is, on this application screen, whether or not the position information of the wafer marks MX _p and MY _p attached to the plurality of sample shot areas SA _p formed on the wafer W has been successfully detected is displayed. As an FTP client, the application acquires the detection results of the position information of the plurality of shot areas SA _p on the wafer W from the main controller 20, and uses the acquired detection results of the position information of the shot areas SA _p as the wafer. image display of the plurality of shot areas SA _p of the shot map on W with (cell display) is displayed on the screen of the display 130D.

  The various marks displayed on the cell are objects that generate an event for displaying a new window for this application when the mouse 130M is clicked. For example, when the operator operates the mouse 130M to select any one mark in the sample shot area, a command message to that effect is issued from this object to the OS. The OS running on the PC 130 posts (posts) this command message to the message queue of this application. The main routine of the application acquires this message, performs so-called dispatch, and releases the CPU to the OS. The OS calls the window procedure of this application, and passes to the window procedure information indicating that this object has been selected as accompanying information together with a command message. In this window procedure, a message handler corresponding to the corresponding pull-down menu is executed with reference to the accompanying information.

A window shown in FIG. 7 is displayed on the screen of the display 130D. In this window, the waveform data corresponding to the photoelectric conversion signal corresponding to the area including the wafer mark MX _p or the wafer mark MY _p in the sample shot area acquired by the alignment system AS is displayed in a graph. Since Y is designated in the text box at the lower left of the window in FIG. 7, the waveform data of the wafer mark MY _p is displayed here. This window is called a waveform display window.

  In FIG. 7, these two waveform data are displayed, but the lower waveform data is raw waveform data corresponding to the photoelectric conversion signal acquired by the alignment system AS. Hereinafter, this waveform data is referred to as “raw waveform data”. This raw waveform data corresponds to the waveform data function p (Y) in FIG.

  Above the “raw waveform data”, the waveform of the differential waveform data created in the mark search process is displayed. Also, a plurality of edge candidate positions calculated based on the peak of the differentiated waveform data p ′ (Y) are displayed by vertical broken lines so as to straddle the raw waveform data and the differentiated waveform data. This differential waveform data corresponds to the waveform data function p ′ (Y) in FIG.

On the right side of the waveform display frame of the two waveform data, the wafer number (Wafer No.) of the selected wafer, the array number (Shot Pos) of the sample shot area, and the design position information (Mark Pos) of the alignment mark are displayed. It is displayed. Under the two waveform data, as described above, the mark for displaying the raw waveform data of the sample shot area is the position detection mark in the X-axis direction or the position detection mark in the Y-axis direction. A text box for the operator to select and input is displayed. By operating the mouse 130M and a keyboard 130K by the operator, the X is designated in the text box, the waveform data displayed is so switched to raw waveform data and its differential waveform data of the wafer mark MX _p.

  When the operator clicks the waveform data with the mouse 130M, a vertical line passing through the point is displayed and the position coordinates of the point are displayed. This vertical line corresponds to the center of the mark template displayed below the raw waveform data.

  As shown in FIG. 8, in addition to the waveform display window, a parameter setting window is displayed on the lower right of the screen on the display 130D. This parameter setting window is a window for setting processing parameters necessary for performing mark recognition processing for the waveform data displayed in the waveform display window.

In the parameter setting window, a sensor for sequence display field and a measured axis display field are displayed from the top, and EGA FIA and Y are displayed in the respective display fields. By this display, the operator confirms that the waveform data displayed in the waveform display window is waveform data related to the Y-axis direction when the wafer mark MY _p acquired by the FIA sensor of the alignment system AS is the measurement target. Can be recognized. The display column of “Sim Pos” below will be described later.

  The various setting fields displayed in the Search Mark Data frame below the “Sim Pos” display field are setting fields for mainly setting search mark design information. First, “Normal” is specified in the setting field of the FIA signal waveform that defines the characteristics of the waveform shape of the mark. This indicates that the shape type of the signal waveform is a normal type. Here, when the waveform of the mark has a waveform shape with a reverse polarity depending on the process type, the reflectance of the background around the mark, etc., “Reverse” may be designated. In addition, “Triple” is set in the “Type” setting field for setting the type of the mark. This is a line-and-space mark composed of three line marks. It is shown that. On the right side of the setting field, text boxes of mark spacing (mark pitch) setting fields a to d are displayed. The mark pitch tolerance setting field ALW-1 and the mark width setting fields W1 to W3 are displayed. The mark width allowable value ALW-2 setting field (text box) is displayed in this order.

  Below the Search Mark Data frame, a Search Parameter frame is displayed. In this frame, a mark recognition parameter setting field used for mark recognition processing is displayed. Here, search mark selection to be detected from the search signal waveform (Search Mark Choice) and an algorithm number (Search Processing Algorithm) applied to the search mark waveform processing are displayed. In the example shown in FIG. 8, Middle and 46 are selected.

  A “Load SIG File” button is displayed at the lower left of the window. When this button is clicked by operating the mouse 130M, the setting values of various parameters set to the actual alignment again in the frame of the search mark data and search parameters displayed in this window are read from the alignment history data. , Display in this window. FIG. 8 shows a state in which the “Load SIG File” button is clicked and various parameter settings used in actual alignment are displayed. As shown in FIG. 8, for example, in the mark parameter frame, “Triple” is displayed in the Type setting column, and “8, 20, 26, 8 [μm]” is displayed in the mark pitch setting columns a to d, respectively. “2 [μm]” is displayed for the mark pitch allowable value ALW-1, W1, W2, and W3 are displayed in the mark width setting column, and 0.5 for the mark width allowable value ALW-2. [Μm] is displayed.

  A “Simulate” button is displayed at the lower right of the window. When the “Simulate” button is clicked by operating the mouse 130M, a mark recognition process simulation is executed using the parameters displayed in the parameter setting window. In the simulation of the mark recognition process, a process equivalent to the mark recognition process in the exposure apparatus 100 described above, that is, an error check for error codes 01 to 0A and a score calculation are performed.

  The operator refers to the waveform data displayed in the waveform display window and the various parameters displayed in the parameter setting window, and evaluates and analyzes the mark recognition process.

  When the waveform data displayed in the waveform display window is clicked with the mouse 130M, the position coordinate of the clicked position is set in the position coordinate setting field (Sim Pos.) Of the parameter setting window. This set position is a position designated by the operator. In the example shown in FIG. 8, -15 μm is set in this setting field. The position coordinates input as text become the specific information in the first embodiment. Fix is a setting for determining whether or not to activate this text box, and is activated by No Fix. The clicked position coordinates are displayed in the waveform display window, and the position coordinates are set to (Sim Pos.) Using the keyboard 130K with reference to the position coordinates displayed by the operator. Good. Further, the operator may directly input the position coordinates of the starting point of the edge based on the design position coordinates of the mark in (Sim Pos.).

  When the Simulate button is clicked in this state, the application starts the processing shown in FIG. As shown in FIG. 9, first, in step 201, Sim Pos. The setting values of various parameters set in the parameter setting window, including the position coordinates specified in, are input to the internal memory.

  Sim Pos. The position coordinates specified in the above are specific information for specifying the edge candidate position for performing the mark recognition process. Methods for specifying the edge candidate position for performing the mark recognition process based on the specific information are roughly classified. There are two ways. First, as shown in the example of the search alignment waveform of the three marks in FIG. 10A, a method of specifying the nearest edge candidate position of the designated position as a position for performing the mark recognition processing. There is. Second, as shown in the example of the three-mark search alignment waveform in FIG. 10B, the edge strength is selected from the edge candidate positions within the predetermined range with the designated position as a reference. There is a method of selecting the edge candidate position having the maximum. In this case, the start edge position of the mark to be detected can be picked up without picking up a noise signal within a predetermined range. In the following, the former is method 1 and the latter is method 2. As the predetermined range in the method 2, for example, a value about the width of one line pattern can be set in wafer alignment, and a value about 3 to 5 times the width of one line pattern in search alignment. Can be set, but any value may be set.

  Returning to FIG. 9, in the next step 203, it is determined whether or not the method 1 is used. Which method is selected is assumed to be set in advance by the operator. If this determination is denied, the process proceeds to step 205, and if affirmed, the process proceeds to step 207. In step 205, method 1 is executed, and in step 207, method 2 is executed. Normally, Method 1 is used during manual assist, and Method 2 is often used during automatic adjustment in lot processing. Either method is used during manual assist or during automatic adjustment. A method may be used. In the example shown in FIG. 8, when the position designated by the operator is −15 μm, the specified edge candidate position is −15.225 μm.

  When step 205 and step 207 are executed and an edge candidate position to be subjected to mark recognition processing is specified, in step 209, mark recognition processing at the specified edge candidate position is performed. As a result, a mark recognition result at the selected edge candidate position (score value if mark recognition is successful, error code if mark recognition fails) can be obtained.

  In the next step 211, the recognition result of the mark recognition process at the edge candidate position is displayed. In this case, if the recognition of the mark is successful, the fact that it was successful, the score value, and the error cause if the recognition of the mark fails are also displayed. In the example shown in FIG. 8, a pop-up window is displayed separately from the waveform display window and the parameter setting window, and an error factor (indicating that the mark width error exceeds the allowable value) is displayed. Further, as shown in FIG. 8, the position coordinates of the center of the mark detected at that time are also displayed in the waveform display window. As shown in FIG. 7, the edge used for the mark recognition process is displayed. The candidate positions are displayed so as to be distinguishable from other edge candidate positions. After step 211 ends, the process ends.

(Parameter adjustment by operator)
As described above, the simulation of mark recognition processing at an arbitrary mark candidate position based on the position specified by the operator in the waveform data using the waveform data actually acquired by the application operating on the PC 130, and The mark recognition result can be displayed. In this simulation, it is possible to perform mark recognition processing under the parameters used in the actual alignment, and it is also possible to perform mark recognition processing under the parameters whose setting values are updated by the parameter setting window. Is possible. Thus, the operator can adjust the mark recognition parameter using the simulation function of this application.

  First, the operator reads the parameter setting value processed by the exposure apparatus 100 by clicking the Load SIG FILE button as it is, visually observes the waveform data with the parameter setting value, and the shape of the waveform data is read. To specify the position where the mark appears to be. Then, the application performs mark recognition processing at the edge candidate position (the position closest to the specified position or the position with the maximum edge strength within a predetermined range) specified from the specified position. As a result, a mark recognition processing result at a position close to the designated position can be obtained.

  For example, as shown in FIG. 8, the mark recognition processing result indicates that the mark recognition has failed and the error factor determined in the mark recognition processing is that the mark width error exceeds the allowable value. Suppose that it was a detection error. In this case, it can be considered that the mark width error exceeds the allowable value is the reason why the mark cannot be recognized correctly. The operator can adjust the parameter by looking at the display result of the error factor and increasing the mark width allowable value (ALW-2) of the processing parameter in the parameter setting window, for example.

  When the operator changes a setting value such as a mark width allowable value (ALW-2) in the parameter setting window and presses the Simulate button, the mark recognition process at the edge candidate position under the changed mark width allowable value. Is re-executed, the set value is appropriate, and the calculated score value is better than the threshold value, the mark detection error is resolved, and the mark can be recognized successfully. .

  The operator can repeatedly eliminate such a mark detection error at a position where a mark is supposed to exist by repeatedly changing the parameter setting and simulating the mark recognition process.

  The operator can set the final setting value of the parameter set through the parameter setting window in the exposure apparatus 100. If the set value of this parameter is appropriate, the occurrence of unnecessary mark detection errors can be reduced in search alignment or wafer alignment for the subsequent wafer W in the exposure apparatus 100, and appropriate mark recognition processing can be performed. Will be able to do.

As described above in detail, according to the first embodiment, the position of the mark in the region on the wafer W including the mark to be detected (wafer marks MX _p , MY _p and search marks SYM, SθM). Detected by the alignment system AS when it is assumed that the mark is located at an arbitrary edge candidate position among the edge candidate positions. An application for acquiring and displaying the recognition result of the mark using the waveform data is provided. In this application, by specifying the approximate position of the mark by operating the mouse 130M or the keyboard 130K, the mark edge candidate position is specified by a predetermined method (method 1 or 2) based on the specified position. It is possible to display the mark detection result using the waveform data when it is assumed that the mark is located at the edge candidate position. In this way, the operator can grasp the recognition result by referring to the display of the mark recognition result at an arbitrary candidate position by the operator's designation.

  Further, according to the first embodiment, the operator can change processing parameters necessary for the mark recognition processing via the parameter setting window. The application can acquire and display a mark recognition processing result at a specified arbitrary mark candidate position under the changed parameters. In this way, the operator can adjust the processing parameters while referring to the mark recognition result at the position where the mark is supposed to exist.

  Further, in the application of the first embodiment, the edge strength within the predetermined range or the nearest edge candidate position of the designated position is set with reference to the designated position input with reference to the waveform display window of the application. One of the maximum edge candidate positions is selected. The operator can freely determine whether to select an edge candidate position closest to the designated position or to select an edge candidate position within a predetermined range centered on the designated position. In this way, even if the operator refers to the waveform display and roughly designates the position for recognizing the mark by operating the mouse, it is possible to execute a reliable mark recognition process in the vicinity of the position. It becomes possible.

  In the first embodiment, the position where the operator recognizes the mark is specified. However, as the position specified by the operator, a position close to the designed mark position is often specified. However, since the actual mark position is generally deviated from the design position depending on the position and orientation of the wafer when loaded on wafer stage WST, more precisely, the design position is It is better to specify a different position. Therefore, this application may have an operator support function when determining the designated position. Below, this support function is demonstrated.

  In this support function, an image diagram of the shot map shown in FIG. 11A is displayed before the operator designates the position. In the cell corresponding to each sample shot area in the shot map, the alignment correction amount of each sample shot area when the wafer alignment is performed on the wafer is displayed. This alignment correction amount is read from the alignment history data stored in the storage device 21.

Here, in FIG. 11A, it is assumed that a sample shot area surrounded by a dotted circle is a shot area in which detection of wafer marks MX _p and MY _p marks has failed. Therefore, as in the first embodiment, when the analysis / evaluation of the mark search processing of the wafer mark in the sample shot area is performed using the application of the PC 130, the operator corrects the alignment correction amount of the shot area. By referring to the vector display, it is possible to designate the approximate mark position for the mark recognition process.

FIG. 11B shows an enlarged vector of alignment correction amounts in a certain sample shot area. In this case, the wafer mark MX _p, when performing the mark recognition of MY _p is wafer marks MX _p, at a position on the design of the MY _p, X component of the vector of the alignment correction amount, by adding respectively the Y component, The position obtained by the addition may be set as the designated position.

  Thus, since the sample shot area on the wafer W is considered to be shifted from the design position by this alignment correction amount, it can be said that it is desirable to designate the mark position in consideration of this alignment correction amount.

  Furthermore, as shown in FIG. 3, the actual position coordinates of the marks on the actual wafer W are slightly different from the position coordinates corrected by the alignment correction amount, and have residuals. Therefore, in addition to the X and Y components of the alignment correction amount, the position of the wafer W may be designated in consideration of the X and Y components of the residual.

In FIG. 12A, the residuals in the alignment in each sample shot area on any one wafer W in the same lot are displayed as vectors. Since the residual is sufficiently small, here, the residual of each shot area is shown enlarged. In the same sample shot area of the wafer W in the same lot, when the residual components are considered to be almost the same, the operator refers to this residual display as shown in FIG. As described above, the design positions of the wafer marks MX _p and MY _p are determined by adding the X component and Y component of the residual vector to the X component and Y component of the alignment correction amount vector, and the X component and Y component. It is more desirable to specify the mark position with correction only.

  In FIG. 12A, the residual component of one wafer W in the same lot is displayed, but as shown in FIGS. 13A and 13B, the remaining components in the lot are displayed. It is also possible to display the residual component in the wafer and calculate the average value of the residual component in each sample shot area. As described above, when there is little variation in the residual component in the same sample shot area on the wafer W in the lot, the average value of the residual component in the remaining wafer W in the lot is designated as the mark position. If it is used for correction, the reliability of the designated position is further improved.

  When the variation in the residual in the same sample shot area of the wafer in the lot exceeds the allowable value, the specified position should not be corrected by such residual (or the average value of the residual). The correction of the designated position by the residual is effective only when the variation in the residual is small within the lot. In a lot, when the residuals of some wafers are significantly different from those of other wafers, the residuals obtained for the wafers may be excluded from the average value calculation.

  If the alignment result is not necessarily reliable, such as when a plurality of wafer marks have failed to be detected in wafer alignment, it is specified according to the coordinate system based on the detection results of the search marks SYM and SθM for that wafer. The position may be corrected.

  In the first embodiment, what is finally displayed on the screen is the recognition result of the mark at one finally specified edge candidate position. However, it goes without saying that the mark recognition processing simulation may be performed and displayed at a plurality of edge candidate positions.

  For example, in step 209, the mark recognition processing is performed for each of a plurality of edge candidate positions in the order close to the specified position or in the order of the edge strength from the edge candidate positions within a predetermined range with the specified position as a reference. In step 211, the recognition results at the respective edge candidate positions are displayed side by side. FIG. 14 shows an example of the displayed recognition result. In FIG. 14, the mark recognition result (error display or the like) is not pop-up displayed, and error factors at a plurality of edge candidate positions are displayed on the lower side of the waveform display window. The display order in this case can also be the order close to the designated position or the order of edge strength.

  In the example shown in FIG. 14, the mark detection error corresponding to the edge candidate position having the highest priority is caused by the mark width error exceeding the allowable value, and the second priority is the priority. The mark detection error corresponding to a high edge candidate position is caused by the variation in edge intensity of each line pattern exceeding an allowable value. If the variation in edge strength exceeds the allowable value, the position is not likely to be a mark position, and therefore the edge candidate position is not a mark position to be detected. Therefore, in this case, the operator changes the mark width allowable value (ALW-2) or the like in the parameter setting window to eliminate the error factor at the edge candidate position.

  As described above, if the recognition result of the mark at a plurality of edge candidate positions can be displayed, the specified edge candidate position can be given a width, and as a result, the mark position to be originally detected can be set. The mark recognition result can be acquired more reliably, and error recovery such as parameter adjustment can be performed more reliably.

<< Second Embodiment >>
Next, a description will be given based on the second embodiment of the present invention. In the first embodiment, the case where mark search processing in search alignment or wafer alignment is evaluated in the PC 130 connected to the exposure apparatus 100 has been described. In the second embodiment, search alignment in the exposure apparatus 100 is performed. Alternatively, a description will be given of a case where processing parameters for mark recognition processing are automatically adjusted when performing wafer alignment.

  Since the configuration of the exposure apparatus according to the second embodiment is the same as the configuration of the exposure apparatus 100 of the first embodiment, detailed description thereof is omitted. A series of exposure operations is also substantially the same as that in the first embodiment except for the wafer alignment process. In the wafer alignment process, after the EGA model formula is determined and the EGA correction amount for each shot area is calculated, if a mark detection error occurs in any of the sample shot areas, the parameter alignment as the final process for wafer alignment is performed. The only difference is that automatic adjustment processing is performed. Therefore, only the automatic parameter adjustment process will be described below.

FIG. 15 is a flowchart showing this parameter automatic adjustment processing. As shown in FIG. 15, first, in step 401, the position coordinates of the design of the mark in the sample shot areas SA _p where mark detection error is corrected using the alignment correction amount obtained from the EGA model equation. The correction method at this time is also the same as the method described in the first embodiment.

  In the next step 403, it is determined whether or not the variation in the residual of the wafer W within the lot is within an allowable range. If this determination is affirmed, the process proceeds to step 405, and if not, the process proceeds to step 407.

In step 405, the wafer W in the lot, X component of the residual alignment correction amount in the sample shot areas SA _p, calculates the average value of the Y component, X component of the alignment correction amount is added to the Y component . The correction method at this time is also the same as the method described in the first embodiment.

  The processing from Step 407 to Step 413 is substantially the same as Step 201 to 211 in FIG. 9 of the first embodiment. That is, in step 409, the parameter setting value of the mark recognition process is read, and if method 1 is selected, the process proceeds to step 411, where the alignment correction amount and the residual are added to the design position coordinates of the wafer mark. The edge candidate position closest to the position where the components are added is calculated, and if method 2 is selected, the process proceeds to step 413, where the alignment correction amount and the residual component are added to the design position coordinates of the wafer mark. The edge candidate position having the strongest edge strength is calculated among the edge candidate positions within the predetermined range with the position obtained by adding the alignment correction amount added as the reference. This calculation process is also the same as that in the first embodiment.

  In step 415, an error factor at the determined edge candidate position stored in the storage device 21 is acquired, and in step 417, a parameter related to the error factor is adjusted. That is, also in the second embodiment, the parameter to be adjusted is selected based on the error factor of the mark detection error as in the first embodiment. For example, if an error related to the mark width has occurred, the parameter directly related to the mark width is corrected, and if an error related to the mark interval has occurred, the parameter directly related to the mark interval is adjusted. Is done. In the next step 419, a mark recognition process is performed at the selected edge candidate position, and it is determined whether or not the mark detection error has been eliminated. If not resolved, the process returns to step 415. In step 415, the error factor is analyzed again, parameters related to the error factor analyzed in step 417 are adjusted, and in step 419, the mark recognition process is performed again.

  In this way, if the error detection mark detection error is not eliminated, as long as a new error detection mark detection error other than the error cause newly occurs, step 415 → step 417 → step 419 → step 421 The process is repeated. As a result, when the mark detection error is finally eliminated, the determination in step 421 is affirmed, and the process ends.

  If the number of wafer marks that failed to be recognized is not one, the above processing is executed for each wafer mark. In this case, when the number of wafer marks that can accurately calculate the EGA model formula is detected, the processing may be terminated there. Further, when the mark recognition result is not improved, the parameter automatic adjustment at the wafer mark may be interrupted, and the process may proceed to the parameter automatic adjustment at the next wafer mark, as in the first embodiment. Similarly, manual parameter adjustment by an operator's operation may be performed.

  After this process, when the wafer W loaded on the exposure apparatus 100 is aligned, a mark recognition process is performed under the adjusted parameters.

  In addition, after the adjustment of this parameter, if the recognition result of the mark recognition process is good and the detection of the mark is successful, the wafer alignment may be performed again using the position information of the mark, The wafer mark alignment system AS may be remeasured.

As described above in detail, also in the second embodiment, an edge candidate position for performing mark recognition processing is specified from among a plurality of edge candidate positions that are candidate mark positions. As in the embodiment, instead of specifying the edge candidate position based on an instruction from the operator, the design position coordinates of the wafer marks MX _p and MY _p are obtained from the shot area of the wafer W that has already been obtained. and alignment correction amount obtained from the EGA model formula for estimating the reference position and the range for specifying the edge candidate position based on the residual at the sample shot areas SA _p in other wafer W in the lot. In this way, it is possible to evaluate the mark recognition process by focusing on a position where the possibility that a wafer mark exists is statistically high, and it is possible to automatically adjust parameters.

  In the second embodiment, the average value of the residuals in the sample shot area of the remaining wafers in the lot is added to the alignment correction amount. However, as in the first embodiment. The residual in any one wafer in the lot may be added to the alignment correction amount as it is. In this case, it is desirable not to add the residual to the alignment correction amount when the variation in the residual is large in the lot.

  In the first and second embodiments, the setting value is adjusted only for the processing parameter directly related to the error factor. However, in reality, the relationship between the error factor and the processing parameter is complicated. There may be. Therefore, after performing the parameter adjustment described in the above embodiments, the adjustment result may be stored and used for subsequent parameter adjustment. For example, when the same error factor has occurred in the past, the parameter adjusted at that time and the set value serve as a guideline for parameter adjustment. Further, when adjustment of a plurality of processing parameters is necessary, subsequent parameter adjustment may be performed in accordance with the priority order of parameter adjustment that was effective. In other words, if a learning function for adjusting parameters based on empirical rules based on past adjustment results is provided, the adjustment efficiency can be increased.

  In each of the above embodiments, the wafer mark recognition process has been mainly described. However, the present invention is not limited to this, and as described above, it is also used for the search mark recognition process.

  However, in the actual process (lot processing), there is little information that can be used to estimate the position of the search mark such as the correction amount corresponding to the alignment correction amount and the residual using the search mark detection result. It is necessary to apply another method as the mark position estimation method. Hereinafter, this method will be described.

  First, in the evaluation of the mark recognition processing of the search mark (SYM) that is measured first, the XY position and rotation of the wafer W are positioned with relatively high accuracy by the alignment of the wafer W performed before loading the wafer W. It is assumed that the design position coordinates are designated positions. Then, in the evaluation of the mark recognition process of the search mark (SθM) to be measured second, from the detected X position and Y position of the search mark SYM obtained by the evaluation of the mark recognition process of the search mark SYM described above. The position coordinate of the expected search mark SθM is set as the designated position.

  In addition to the estimation of the designated position, parameter adjustment and the like can be realized for the search mark in the same manner as the evaluation of the mark recognition process for the wafer mark in each of the above embodiments.

  The information used for specifying the edge candidate position is not limited to the alignment correction amount in the sample shot area of the wafer or the residual in the wafer alignment performed on other wafers in the lot. It may be information on the experience or design information of the wafer mark. For example, information on the arrangement error (so-called shot-to-shot error) of shot areas formed on the wafer measured in advance on the wafer, the exposure apparatus 100 measured in advance, and other information used in the original process Information regarding the deviation of the stage coordinate system from the exposure apparatus may be used for selection of the edge candidate position.

  Further, in each of the above embodiments, when the residual of the sample shot area exceeds the predetermined threshold value for other wafers in the lot, the residual is not used for calculating the average value. Good.

  In the above embodiments, the mark position information is detected by differentiating the mark detection waveform and calculating the feature amount of the mark from the differentiation result. However, the mark position information can also be detected by other methods. is there. For example, the correlation processing between the mark detection waveform data and the template waveform data may be performed, and the position having the highest correlation value may be set as the mark position. In this case, the correlation value at each position when the template pattern obtained by the correlation process is scanned with respect to the detected waveform data can be used as a score.

  In each of the embodiments described above, the mark search processing in the one-dimensional waveform has been described. However, the present invention is not limited to this, and can be applied to search for a mark in two-dimensional image data. FIG. 16 schematically shows a shot map display and a two-dimensional cross mark formed in a circuit pattern on a certain shot area in the shot map.

  Also in this case, as in each of the above embodiments, the two-dimensional image signal data is subjected to differentiation processing, a plurality of edge candidate positions are extracted, and the edge candidate positions are aligned with the starting point of the template waveform of the mark. It is possible to quantify the degree of correlation between the two marks with the score and detect the mark position information based on the score, but the mark cannot be properly recognized due to the influence of the surrounding circuit pattern. In such a case, the mark recognition process is evaluated in the same manner as in the above embodiments. The position designated at that time may be based on the design position coordinates of the mark in the shot area or the measured value of the position of the mark measured in the past.

  In the above-described waveform processing including the example of the two-dimensional image, the present invention is applied to a method of detecting the position of the mark based on the edge candidate position extracted by performing differentiation on the detected raw waveform data. However, the present invention is not limited to this. For example, taking the case of the above-described two-dimensional image processing as an example, the template pattern of the mark is scanned in the two-dimensional direction with respect to the raw image data, and the position having the highest correlation is detected as the mark position. The present invention can also be applied to image processing, that is, evaluation of image processing that detects the position of a mark using image shading, and is not limited to image processing methods such as contour correlation and normalized correlation.

  Even in this case, it is possible to adjust the image processing parameters appropriately by searching for the mark based on the position based on the design position coordinate of the mark or the measured position of the mark measured in the past. It becomes.

  In each of the above embodiments, the processing parameters of the processing are adjusted based on the evaluation result of the mark search. However, the present invention is not limited to this. For example, a mark for which a mark detection error has not been finally eliminated may be excluded from a measurement target in alignment in subsequent wafer processing. That is, the mark to be detected may be selected based on the evaluation result of the mark search. Further, the processing procedure may be optimized such as changing the order of the processing procedure of the mark recognition algorithm.

  As a factor causing the mark recognition error, data other than the waveform data detected by the alignment system AS can be used. For example, the focus shift, exposure amount, wafer flatness, wafer stage, and reticle stage synchronization accuracy error when the mark is transferred and formed are logged by the exposure device where the transfer was formed. The processing parameters may be adjusted with reference to the result.

  In each of the above embodiments, the mark to be detected is an L / S mark. However, the present invention is not limited to this, and may be a single line mark, a box mark, or a set of these marks. . The mark to be detected may be two-dimensional or one-dimensional as long as it is a unique mark, and the mark shape and size may be arbitrary.

  In each of the embodiments described above, the alignment system AS includes an off-axis FIA system (imaging type alignment sensor) and an LSA sensor. However, the present invention is not limited to this, and only one of the sensors is used. An alignment system having In addition, the alignment system AS may be any of the TTR (Through The Reticle) method, the TTL (Through The Lens) method, and the off-axis method, and the image forming method in which the detection method is employed in the FIA system or the like. Other than the method (image processing method), for example, a method of detecting diffracted light or scattered light may be used. For example, the alignment mark on the wafer is irradiated with a coherent beam substantially perpendicularly, and the diffracted light of the same order (± first order, ± second order,..., ± n order diffracted light) generated from the mark is detected by interference. An alignment system may be used. In this case, the diffracted light may be detected independently for each order, and the detection result of at least one order may be used, or a plurality of coherent beams having different wavelengths may be irradiated to the alignment mark, and each order for each wavelength. The diffracted light may be detected by interference.

  In each of the above embodiments, the case where the alignment mark is detected on the wafer has been described. However, the present invention can also be applied to the alignment mark formed on the reticle, that is, the detection waveform of the reticle alignment mark. Needless to say.

  Further, the present invention is not limited to the step-and-scan type exposure apparatus as in the above-described embodiments, but includes a step-and-repeat type or proximity type exposure apparatus (such as an X-ray exposure apparatus). The present invention can be applied in exactly the same manner to various types of exposure apparatuses.

In each of the embodiments described above, as a light source, a far ultraviolet light source such as a KrF excimer laser or an ArF excimer laser, a vacuum ultraviolet light source such as an F ₂ laser, or an ultrahigh pressure mercury lamp that emits a bright line (g line, i line, etc.) Etc. can be used. In addition, when light in the vacuum ultraviolet region is used as the illumination light for exposure, it is not limited to the laser beam output from each of the light sources described above, but a single infrared or visible region oscillated from a DFB semiconductor laser or fiber laser. For example, harmonics obtained by amplifying a wavelength laser beam with a fiber amplifier doped with erbium (Er) (or both erbium and ytterbium (Yb)) and converting the wavelength into ultraviolet light using a nonlinear optical crystal may be used. .

  Furthermore, the present invention may be applied to an exposure apparatus that uses EUV light, X-rays, or charged particle beams such as electron beams and ion beams as exposure illumination light. In addition, the present invention may be applied to an immersion type exposure apparatus in which a liquid is filled between the projection optical system PL and the wafer W, which is disclosed in, for example, International Publication No. WO99 / 49504. Further, as disclosed in, for example, Japanese Patent Application Laid-Open No. 10-214783 and International Publication No. WO98 / 40791, the exposure apparatus includes an exposure position where a reticle pattern is transferred via a projection optical system, and a wafer. A twin wafer stage type in which a wafer stage is arranged at each measurement position (alignment position) where mark detection by the alignment system is performed, and an exposure operation and a measurement operation can be performed substantially in parallel may be used. Further, the projection optical system PL may be any of a refraction system, a catadioptric system, and a reflection system, and may be any one of a reduction system, an equal magnification system, and an enlargement system. As long as the national laws of the designated country designated in this international application or the selected selected country permit, the disclosure in the above-mentioned gazette and the corresponding international publication pamphlet is incorporated as a part of the description of this specification.

  In the above-described embodiment, a light-transmitting mask in which a predetermined light-shielding pattern (or phase pattern / dimming pattern) is formed on a light-transmitting substrate, or a predetermined reflecting pattern is formed on a light-reflecting substrate. Although the formed light reflection type mask is used, an electronic mask that forms a transmission pattern, a reflection pattern, or a light emission pattern based on electronic data of a pattern to be exposed may be used instead of these masks. Such an electronic mask is disclosed, for example, in US Pat. No. 6,778,257. This US Patent No. 6,778,257 is incorporated herein by reference.

  Note that the above-described electronic mask is a concept including both a non-light-emitting image display element and a self-light-emitting image display element. Here, the non-light-emitting image display element is also called a spatial light modulator, and is an element that spatially modulates the amplitude, phase, or polarization state of light. It can be divided into a reflective spatial light modulator. The transmissive spatial light modulator includes a transmissive liquid crystal display element (LCD), an electrochromic display (ECD), and the like. The reflective spatial light modulator includes a DMD (Digital Mirror Device or Digital Micro-mirror Device), a reflective mirror array, a reflective liquid crystal display element, an electrophoretic display (EPD), an electronic paper (or electronic paper). Ink), and a light diffraction light valve (Grating Light Value).

  Self-luminous image display elements include CRT (Cathode Ray Tube), inorganic EL (Electro Luminescence) display, field emission display (FED: Field Emission Display), plasma display (PDP: Plasma Display Panel), A solid light source chip having a light emitting point, a solid light source chip array in which a plurality of chips are arranged in an array, or a solid light source array in which a plurality of light emitting points are formed on a single substrate (for example, an LED (Light Emitting Diode) display, OLED) (Organic Light Emitting Diode) display, LD (Laser Diode) display, etc.). Note that when a fluorescent material provided in each pixel of a known plasma display (PDP) is removed, a self-luminous image display element that emits light in the ultraviolet region is obtained.

  The present invention is not limited to an exposure apparatus for manufacturing a semiconductor, but is used for manufacturing a display including a liquid crystal display element. An exposure apparatus for transferring a device pattern onto a glass plate and a device used for manufacturing a thin film magnetic head. The present invention can also be applied to an exposure apparatus that transfers a pattern onto a ceramic wafer, and an exposure apparatus that is used for manufacturing an imaging device (CCD or the like), micromachine, organic EL, DNA chip, and the like. Further, in order to manufacture reticles or masks used in not only microdevices such as semiconductor elements but also light exposure apparatuses, EUV exposure apparatuses, X-ray exposure apparatuses, electron beam exposure apparatuses, etc., glass substrates or silicon wafers, etc. The present invention can also be applied to an exposure apparatus that transfers a circuit pattern. Here, in an exposure apparatus using DUV (far ultraviolet) light, VUV (vacuum ultraviolet) light, or the like, a transmission type reticle is generally used. As a reticle substrate, quartz glass, fluorine-doped quartz glass, meteorite, Magnesium fluoride or quartz is used. Further, in a proximity type X-ray exposure apparatus or an electron beam exposure apparatus, a transmission mask (stencil mask, membrane mask) is used, and a silicon wafer or the like is used as a mask substrate.

  Further, in each of the above embodiments, the case where the present invention is applied to the exposure apparatus and its analysis / evaluation has been described. However, in addition to the exposure apparatus, the inspection apparatus, the transport apparatus, the measurement apparatus, the test apparatus, and other apparatuses may use waveforms. The present invention can be applied to analysis and evaluation of any apparatus that performs processing or image processing. In this case, it is also possible to apply the present invention by incorporating the above application function into various apparatus bodies such as an exposure apparatus instead of an information processing apparatus such as a personal computer.

  The semiconductor device includes a step of designing a function and performance of the device, a step of manufacturing a reticle based on the design step, a step of manufacturing a wafer from a silicon material, and a reticle pattern on the wafer by the exposure apparatus 100 of the above-described embodiment. It is manufactured through a transfer step, a device assembly step (including a dicing process, a bonding process, and a packaging process), an inspection step, and the like.

  In each of the above embodiments, the operating system for controlling the PC 130 is Windows (registered trademark). However, it is needless to say that other operating systems may be used as long as they are multitasking operating systems that provide a GUI. Such an OS may be preemptive or non-preemptive.

  Currently, the OS as described above supports a wide variety of programming development languages and APIs (application programming interfaces), and it is easy to develop software for the applications. Basically, it is only necessary to design the behavior of the application with respect to the event that has occurred (that is, the operation by the operator), specifically, the processing content such as the message handler for the message sent to the application.

  As described above, the evaluation system and the evaluation method of the present invention are suitable for evaluating the search processing of the detection target using the photoelectric conversion signal detected so as to correspond to the region including the detection target.

Claims (26)

Photodetection of a detection area including a detection target that is one of a plurality of marks formed on an object to acquire a photoelectric conversion signal, and evaluate search processing of the detection target using the photoelectric conversion signal An evaluation system that
The detection using the photoelectric conversion signal in the case where it is assumed that the detection target is located at an arbitrary candidate position among a plurality of candidate positions in the detected region that are candidates for the position of the detection target. An acquisition device for acquiring a detection result of the object;
A specifying device that specifies at least one candidate position from among the plurality of candidate positions based on specifying information for specifying the candidate position of the detection target;
Based on the detection result acquired by the acquisition device on the assumption that the detection target is located at the candidate position specified by the specific device, search processing of the detection target using the photoelectric conversion signal is performed. An evaluation device to evaluate;
Based on the results of statistical processing using empirical information already obtained or design information of the detection target and position information of other marks on the object excluding the mark that is the detection target included in the detection area And an estimation device that estimates specific information for specifying the candidate position of the detection target . The evaluation system according to claim 1,
An input device for inputting specific information for specifying the at least one candidate position;
The specific device is:
An evaluation system that identifies the candidate position based on the identification information input by the input device. The evaluation system according to claim 1 ,
The detection target is one of a plurality of marks formed by the same process on a plurality of objects,
The estimation device includes:
Among the plurality of objects, the object on which the detection target is formed is the detection target on the other object with respect to a reference obtained by statistical processing using position information of a plurality of marks on the other object. An evaluation system that corrects the specific information based on information about residuals of measured position information of marks provided at the same position. In the evaluation system according to claim 3 ,
The detection target is one of a plurality of marks formed by the same process on at least two objects,
The estimation device includes:
Of the at least two objects, an average value of the residuals corresponding to marks provided at the same position on the remaining objects other than the object on which the detection target is formed is calculated, and based on the average value An evaluation system for correcting the specific information. The evaluation system according to claim 4 ,
The estimation device includes:
An evaluation system that, when the variation of the residual corresponding to the mark provided at the same position on the remaining object exceeds a predetermined threshold, does not use the residual for the calculation of the average value . The evaluation system according to claim 1,
The specific information includes
An evaluation system in which any one of information related to at least one specific position in the region and information related to at least one specific range in the region is designated. The evaluation system according to claim 1,
When there are a plurality of candidate positions specified by the specifying device,
The acquisition device includes:
Obtaining a detection result corresponding to each candidate position when it is assumed that the detection target is located at each of the plurality of candidate positions;
The evaluation device is
An evaluation system that ranks detection results corresponding to the candidate positions in a predetermined order. The evaluation system according to claim 7 ,
The predetermined order is:
The evaluation system which is any one of the order according to the characteristic of the signal corresponded to the said detection target, and the order close | similar to the said specific position. The evaluation system according to claim 1,
An evaluation system further comprising a display device that displays a detection result of the detection target evaluated by the evaluation device. The evaluation system according to claim 1,
An evaluation system further comprising an adjustment device that adjusts a signal acquisition device that acquires a photoelectric conversion signal corresponding to a region including the detection target, based on a detection result of the detection target evaluated by the evaluation device. The evaluation system according to claim 10 ,
An evaluation system further comprising an instruction device that instructs the signal acquisition device adjusted by the adjustment device to acquire again a photoelectric conversion signal corresponding to a detection region including the detection target. The evaluation system according to claim 1,
The detection target is a mark provided on an object,
The evaluation system includes a detection result of the detection target including mark detection error information detected based on an index value indicating a difference between design information and actual measurement information regarding each of a plurality of different features of the mark. The evaluation system according to claim 12 ,
The detection target is a line and space mark provided on the object,
The evaluation system includes a plurality of different features to be detected including at least one of a mark width of a line and space mark, a mark pitch, and the number of lines. Photoelectric detection is performed on a detection area including a detection target that is one of a plurality of marks formed on the object to obtain a photoelectric conversion signal, and evaluation processing for the detection target using the photoelectric conversion signal is evaluated. An evaluation method for
A specifying step of identifying at least one candidate position from which a detection result of the detection target using the photoelectric conversion signal is acquired from among a plurality of candidate positions in the detected region that are candidates for the position of the detection target When;
An acquisition step of acquiring a detection result of the detection target using the photoelectric conversion signal at the candidate position specified in the specification step;
An evaluation step of evaluating the detection target search process using the photoelectric conversion signal based on the detection result acquired in the acquisition step;
Based on the results of statistical processing using empirical information already obtained or design information of detection targets and position information of other marks on the object excluding marks as detection targets included in the detection region An estimation step of estimating specific information for specifying the candidate position . The evaluation method according to claim 14 ,
Prior to the specific process,
An input step of inputting the specifying information to specify the at least one candidate position;
In the specific step,
An evaluation method for identifying the candidate position based on the identification information input in the input step. The evaluation method according to claim 15 ,
The detection target is one of a plurality of marks formed by the same process on a plurality of objects,
In the estimation step,
Among the plurality of objects, the object on which the detection target is formed is the detection target on the other object with respect to a reference obtained by statistical processing using position information of a plurality of marks on the other object. An evaluation method for correcting the specific information based on information on a residual of measured position information of marks provided at the same position. The evaluation method according to claim 16 , wherein
The detection target is one of a plurality of marks formed by the same process on at least two objects,
In the estimation step,
Of the at least two objects, an average value of the residuals corresponding to marks provided at the same position on the remaining objects other than the object on which the detection target is formed is calculated, and based on the average value An evaluation method for correcting the specific information. The evaluation method according to claim 17 ,
In the estimation step,
Evaluation method in which the residual is not used for calculation of the average value when the variation of the residual corresponding to the mark provided at the same position on the remaining object exceeds a predetermined threshold . The evaluation method according to claim 14 ,
The specific information includes
An evaluation method in which one of information on at least one specific position in the region and information on at least one specific range in the region is designated. The evaluation method according to claim 14 ,
When there are a plurality of candidate positions specified in the specifying step,
In the acquisition step,
Obtaining a detection result corresponding to each candidate position when it is assumed that the detection target is located at each of the plurality of candidate positions;
In the evaluation step,
An evaluation method for ranking the detection results corresponding to the candidate positions in a predetermined order. The evaluation method according to claim 20 , wherein
The predetermined order is:
The evaluation method which is either one of the order according to the characteristic of the signal corresponded to the said detection target, and the order close | similar to the said specific position. The evaluation method according to claim 14 ,
The evaluation method characterized by further including the display process which displays the detection result of the said detection target evaluated in the said evaluation process. The evaluation method according to claim 14 ,
An evaluation method further comprising an adjustment step of adjusting a signal acquisition device that has acquired a photoelectric conversion signal corresponding to a region including the detection target based on a detection result of the detection target evaluated in the evaluation step. . The evaluation method according to claim 23 ,
An evaluation method further comprising an instruction step for instructing the signal acquisition device adjusted in the adjustment step to acquire again a photoelectric conversion signal corresponding to a detection region including the detection target. The evaluation method according to claim 14 ,
The detection target is a mark provided on an object,
An evaluation method in which a detection result of the detection target includes mark detection error information detected based on an index value indicating a difference between design information and actual measurement information regarding each of a plurality of different features of the mark. The evaluation method according to claim 25 ,
The detection target is a line and space mark provided on the object,
The evaluation method includes a plurality of different features to be detected including at least one of a mark width, a mark pitch, and a number of lines of a line and space mark.