Inspection flow determination device, charged particles beam device, and program

Abstract

To make it possible to create inspection data adjusted to a desired number of inspection points and the number of times of FOV movement in designated inspection time.SOLUTION: An inspection flow determination device includes an inspection time estimation unit 102 that estimates inspection time required to inspect an inspection point extracted under predetermined conditions from grouping data in which inspection points of a wafer to be inspected are grouped so as to belong to at least one FOV (Field of View), and an inspection data extraction unit 106 that extracts the inspection point extracted with conditions selected based on the estimated inspection time as extraction conditions. The inspection time estimation unit extracts the inspection point from the grouping data based on a FOV selection rule for determining whether or not to perform or skip FOV movement using number of the FOV movement as a parameter and an inspection point selection rule for determining whether or not to actually inspect or skip the inspection point with the number of inspection points actually inspected in the FOV as a parameter.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present invention relates to an inspection flow determination device, a charged particle beam device, and a program.

Background Art

[0002] When forming devices and wirings on a semiconductor wafer (hereinafter referred to as "wafer"), after forming films of semiconductors, conductors, and insulators on the wafer, a mask pattern of a photomask is transferred to a photosensitive resist by photolithography technology, and the films are etched using the resist as an etching mask. In these processes, a length measurement SEM (Scanning Electron Microscope) is widely used for evaluating the dimensions of mask pattern transfer and the processed finish dimensions after etching.

[0003] SEM can evaluate not only dimensions and shapes but also electrical characteristics of a sample. For example, a potential contrast image can be formed based on detection of secondary electrons and the like obtained by irradiating the sample with an electron beam, and the electrical characteristics of elements formed on the sample can be evaluated based on analysis of the potential contrast image. Also, the resistance value can be evaluated from the steady-state charge amount accompanying electron beam irradiation, and the capacitance characteristics can be evaluated from the transient response characteristics of the charge amount.

[0004] In the evaluation by SEM, the stage is moved so that an arbitrary inspection point enters the FOV (Field of View), and the dimensions, shape data, or electrical characteristics of the inspection pattern are acquired to evaluate the performance. Therefore, the inspection time required for the evaluation by SEM is the sum of the movement time to the FOV and the measurement time of each inspection point within the FOV.

[0005] With the recent high integration of semiconductors, the number of inspection points in the evaluation process has increased significantly. Therefore, the mainstream method for creating a recipe that specifies the positions, magnifications, image qualities, etc. required for evaluation is to automatically generate it from CAD data. Also, in recipe creation, not only the extraction of inspection point positions but also a technique for determining the positions where FOVs should be arranged, including the correspondence such as which FOV each inspection point is inspected in, is known (see Patent Documents 1 and 2).

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0007] With the high integration of semiconductors, when evaluating a large number of finer inspection points over a wide range such as the entire wafer surface using an SEM, compared to an optical inspection device, each inspection point is measured while moving the FOV in a very small range. Therefore, the inspection throughput becomes a bottleneck. Even though the working time for recipe creation can be shortened by automating recipe creation in response to the increase in the number of inspection points, the problem that the time required for inspection becomes too long is not solved. Also, in order to suppress the increase in inspection time, even if inspection coordinate data is created by extracting inspection points so that the inspection is completed within the specified time, there is no known technique for creating data adjusted to the desired number of inspection points and the number of FOV movements while considering the relationship such as which FOV each inspection point is inspected in.

Means for Solving the Problems

[0008] An inspection flow determination device according to an embodiment of the present invention includes an inspection time estimation unit that estimates the inspection time required to inspect inspection points extracted under predetermined conditions from grouping data obtained by grouping inspection points of a wafer to be inspected so as to belong to at least one FOV (Field of View), and an inspection data extraction unit that extracts, as inspection points of inspection data indicating inspection points actually inspected for the wafer, inspection points extracted under conditions selected based on the inspection time estimated by the inspection time estimation unit as extraction conditions. The inspection time estimation unit extracts inspection points from the grouping data based on an FOV selection rule that determines whether to perform or skip FOV movement using the number of FOV movements as a first parameter, and an inspection point selection rule that determines whether to actually inspect or skip inspection points using the number of inspection points actually inspected in the FOV as a second parameter.

Advantages of the Invention

[0009] Inspection data adjusted to a desired number of inspection points and the number of FOV movements can be created within the specified inspection time. Other problems and novel features will become apparent from the description of this specification and the attached drawings.

Brief Description of the Drawings

[0010]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5A

Figure 5B

Figure 6A

Figure 6B

Figure 7A

Figure 7B

Figure 8A

Figure 8B

Figure 9A

Figure 9B

Figure 10

Figure 11

Figure 12

Figure 13

Figure 14A

Figure 14B

Mode for Carrying Out the Invention

[0011] Hereinafter, embodiments of the present invention will be described with reference to the drawings. Each form shown in this example is an example for realizing the present invention, and does not limit the technical scope of the present invention. For example, the examples described below are described in detail for easy understanding of the present invention, and are not necessarily limited to those having all the configurations described. Also, it is possible to replace a part of the configuration of one example with the configuration of another example, and it is also possible to add the configuration of another example to the configuration of one example. Also, it is possible to add, delete, or replace other configurations for a part of the configuration of each example. In the examples, members having the same function are denoted by the same reference numerals, and repeated descriptions thereof are omitted unless particularly necessary. Also, the prior art part not directly related to the present invention is omitted.

[0012] When there are a plurality of elements having the same or similar functions, they may be described by attaching different subscripts to the same reference numeral. However, when it is not necessary to distinguish a plurality of elements, the description may be made omitting the subscripts.

[0013] Expressions such as "first", "second", "third", etc. in this specification and the like are attached to identify components, and do not necessarily limit the number, order, or content thereof. Also, the numbers for identifying components are used for each context, and the numbers used in one context do not necessarily indicate the same configuration in other contexts. Also, it does not prevent a component identified by a certain number from also having the functions of a component identified by another number.

[0014] The positions, sizes, shapes, ranges, etc. of each configuration shown in the drawings and the like may not represent the actual positions, sizes, shapes, ranges, etc. in order to facilitate understanding of the invention. For this reason, the present invention is not necessarily limited to the positions, sizes, shapes, ranges, etc. disclosed in the drawings and the like.

[0015] The publications, patents, and patent applications cited in this specification constitute a part of the description of this specification as they are.

[0016] In this specification, components represented in the singular form shall include the plural form unless clearly indicated otherwise in the context.

[0017] FIG. 1 is a schematic configuration diagram of a charged particle beam apparatus. Here, an electron microscope using an electron beam as the charged particle beam is taken as an example, but an ion microscope or the like using an ion beam as the charged particle beam may also be used. The charged particle beam apparatus includes an electron microscope main body 200 and a control device 100, and an input device 120 and a display device 121, which serve as interfaces for the user to operate the electron microscope main body, are connected to the control device 100.

[0018] The electron microscope main body 200 mainly includes a charged particle optical system (here, an electron optical system), a stage mechanism system, and a group of controllers 201.

[0019] The electron optical system mainly includes an electron source 202, a blanker 203 for pulsing the electron beam from the electron source 202, a deflector 204 for controlling the irradiation position of the electron beam on the sample 210, an electron lens 207 for focusing the electron beam on the sample 210, and a detector 205 for detecting signal electrons emitted when the electron beam irradiates the sample (wafer) 210. The stage mechanism system includes a sample stage 208 on which the sample 210 to be inspected is placed and a stage mechanism 209 for driving the sample stage 208. The electron optical system and the stage mechanism system are arranged in a vacuum environment. Although not shown in FIG. 1, when inspecting the electrical characteristics of elements, an irradiation optical system for controlling the sample potential of the sample 210 may be provided. The irradiation optical system includes, for example, a laser light source for irradiating laser light and an optical system for controlling the irradiation location thereof in order to perform charge control of the sample 210.

[0020] These electron optical systems and stage mechanism systems are controlled by a group of controllers 201 that control their respective components. The control device 100 outputs a control signal to the group of controllers 201 according to, for example, a program for the electron microscope main body 200 to execute an inspection. The group of controllers 201 controls each component according to the control signal to execute an inspection of the sample 210. Further, the control device 100 is connected to the wafer inspection management device 140 via the network 130. The wafer inspection management device 140 provides the control device 100 with inspection information of the wafer 210 to be inspected.

[0021] The control device 100 is realized by an information processing device (computer) mainly including a processor (Central Processing Unit: CPU) 151, a memory 152, a storage device 153, an input interface (I / F) 154, an output I / F 155, a communication I / F 156, and a bus 157 as shown in FIG. 2. The processor 151 functions as a functional unit that provides a predetermined function by executing processing according to a program loaded in the memory 152. The storage device 153 stores data and programs used by the functional unit. The input I / F 154 is connected to an input device 120 such as a keyboard, a pointing device, and an operation panel, and the output I / F 155 is connected to a display device 121. The communication device I / F 156 enables communication with other information processing devices, for example, the wafer inspection management device 140 via the network 130. These are communicably connected to each other by the bus 157.

[0022] In the following description, when explaining the processing by a program, the program, functional units, etc. may be mainly described. However, the main hardware for them is a processor or an information processing apparatus (computer) configured to include the processor and the like. The information processing apparatus executes processing according to a program read onto a memory while appropriately using resources such as a memory and a communication interface by the processor. In FIG. 2, an example of a CPU is shown as the processor, but a GPU (Graphical Processing Unit) or the like may be used. Further, the processing for realizing the function is not limited to software program processing, and can also be implemented by a dedicated circuit. For the dedicated circuit, an FPGA (Field Programmable Gate Array), an ASIC (Application Specific Integrated Circuit), etc. are applicable.

Example

[0023] The control device 100 has a function of receiving inspection information of a wafer to be inspected from the wafer inspection management device 140 and determining an inspection flow of the wafer.

[0024] FIG. 3 is a functional block diagram of a control device 100 that determines a wafer inspection flow and executes an inspection using a charged particle beam device. The grouping data 111 created by the wafer inspection management device 140 and transmitted to the control device 100 is stored in the storage unit 110. The grouping data 111 is data obtained by grouping inspection points on the wafer so that they belong to at least one FOV. When the grouping data 111 is input to the data input unit 101, the inspection time estimation unit 102 estimates the time required for wafer inspection (hereinafter referred to as "inspection time") using the number of FOV movements and the number of inspection points as parameters based on the input grouping data 111. At this time, the number of FOV movements (first parameter) and the number of inspection points actually inspected in the FOV (second parameter), which are parameters for estimating the inspection time, are respectively used in a first rule (hereinafter referred to as "FOV selection rule") for determining whether to perform or skip FOV movement, and a second rule (hereinafter referred to as "inspection point selection rule") for determining whether to perform or skip inspection of each inspection point in the FOV. By further selecting inspection points by the second rule for the FOV selected by the first rule, the inspection points to be actually inspected are extracted, and the inspection time in that case is estimated. The detailed setting of the FOV selection rule is performed by the FOV selection rule setting unit 103, and the detailed setting of the inspection point selection rule is performed by the inspection point selection rule setting unit 104.

[0025] Based on the inspection time estimated by the inspection time estimation unit 102, the extraction condition setting unit 105 sets conditions for extracting desired inspection coordinate data. The inspection data extraction unit 106 extracts data of inspection points for executing an inspection based on the extraction conditions set by the extraction condition setting unit 105, and stores it in the storage unit 110 as inspection data 112. In this way, the inspection data 112 is created as a list of inspection points with the number of FOV movements and the number of inspection points adjusted so that the inspection of the wafer is completed within a specified time based on the grouping data 111 having a relationship such as which FOV each inspection point on the wafer is inspected in.

[0026] The inspection control unit 108 controls the stage mechanism 209 according to the inspection data 112 stored in the storage unit 110, moves the sample stage 208 on which the sample (wafer) 210 with the pattern formed thereon is placed (stage movement), and controls the deflector 204 to finely adjust the position of the FOV (image shift). At this time, it is preferable to display the FOV on the display device 121 so that the user can confirm the FOV. In a state where the FOV to be inspected is defined, the inspection control unit 108 sequentially inspects each inspection point within the FOV. When the inspection of the inspection points within the FOV is completed, the inspection control unit 108 moves the sample stage 208 to the next FOV. When the inspection of all the inspection points listed in the inspection data 112 is executed in these series of processes, the inspection is completed. Note that the inspection of the inspection points may be the measurement of the dimensions of the pattern of the inspection points or the evaluation of the electrical characteristics of the pattern of the inspection points.

[0027] Here, an example in which the control device 100 creates the inspection data 112 from the grouping data 111 has been shown. However, the inspection data 112 may be created by another information processing device, for example, the wafer inspection management device 140, and the inspection data 112 may be sent to the control device 100. A device that executes the functional blocks 101 to 107 for creating the inspection data 112, that is, for determining the inspection flow, may also be referred to as an inspection flow determination device. Hereinafter, the processing by the inspection flow determination device will be described in detail.

[0028] (Inspection time estimation unit 102) The inspection time estimation unit 102 estimates the inspection time using the number of FOV movements and the number of inspection points actually inspected in the FOV as parameters. The formula for estimating the inspection time is, for example, as shown in (Equation 1).

[0029]

Equation

[0030] Here, T is the total inspection time, t SM , t IS , t ITare, respectively, the average time taken for stage movement by the stage mechanism 209, the average time taken for image shift by the deflector 204, and the average time taken for measurement at the inspection points. Also, num FOV is the total number of FOVs defined in the grouping data 111. x m is a binary variable that becomes 1 or 0 depending on whether to perform or skip the m-th FOV movement (stage movement and image shift), z m is the number of inspection points included in the m-th FOV, ratio IT is the ratio of the number of inspection points actually inspected among the inspection points included in the FOV.

[0031] Here, by using (Equation 2) to transform (Equation 1), (Equation 3) is obtained.

[0032]

Equation

[0033] Here, ratio FOV is the FOV movement ratio obtained by dividing the number of FOVs selected for performing FOV movement by the total number of FOVs num FOV . Also, num IT is the total number of inspection points included in the FOVs selected for performing FOV movement.

[0034]

Equation

[0035] Here, t SM , t IS , t IT are respectively values specific to the charged particle beam apparatus for performing inspection. (Equation 3) indicates that regardless of the criteria for selecting the FOVs for which FOV movement is performed and the inspection points actually inspected within the FOVs, the total inspection time T depends only on the FOV movement ratio ratio FOV , the inspection point ratio ratio ITThis indicates that it is determined by this. Therefore, without affecting the inspection time calculated by the inspection time estimation unit 102, it is possible to set a FOV selection rule and an inspection point selection rule for creating desired inspection coordinate data, respectively.

[0036] (FOV selection rule setting unit 103 and inspection point selection rule setting unit 104) FIG. 4 is an example of a rule setting screen displayed on the display device 121 by the FOV selection rule setting unit 103 and the inspection point selection rule setting unit 104. The setting of the FOV selection rule and the inspection point selection rule can also be set inside the inspection flow determination program or in a setting file that stores various measurement condition settings, but a configuration in which the user can set desired extraction conditions is preferable. Here, in the selection rule setting screen 400 displayed on the display device 121, desired conditions can be selected for the FOV selection rule and the inspection point selection rule, respectively, and the selection rules selected here are set in the FOV selection rule setting unit 103 and the inspection point selection rule setting unit 104.

[0037] FIG. 5A is a schematic diagram for explaining an example of a rule for selecting whether to perform movement to the FOV defined in the grouping data 111 or skip it in the FOV selection rule setting. In this example, the FOVs are sorted in descending order according to the number of inspection points in the FOV, and it is determined whether to perform FOV movement or skip it based on the set threshold value. FOV_id is an ID for uniquely identifying the FOV, and num IT_all is the total number of all inspection points defined in the grouping data 111. Here, the number of inspection points belonging to the FOV is represented by the product of the total number of inspection points num IT_all and the ratio it occupies. For example, assuming that the FOV movement ratio ratio FOV is set to 0.8, and the FOV_id: 682 is the FOV at the num FOV ×0.8-th position from the top among the FOVs arranged in descending order of the number of inspection points in the FOV. In this case, it is determined that for FOVs in which the number of inspection points in the FOV is equal to or more than the number of inspection points of FOV_id: 682, FOV movement is performed, and FOVs less than that are skipped.

[0038] Note that the FOV selection rules are not limited to the above description, and they may be sorted in ascending order. Additionally, other methods are conceivable, such as dividing the FOVs into multiple ranks according to the number of inspection points defined in the grouping data 111, randomly skipping a certain percentage of FOVs within each rank, or simply randomly selecting FOVs to move.

[0039] On the other hand, FIG. 5B is a schematic diagram for explaining an example of a rule for selecting whether to perform or skip the inspection of the inspection points defined in the grouping data 111 within the FOV in the setting of the inspection point selection rule. A plurality of inspection points 301 are included inside the FOV 300. In this example, the inspection point distance is calculated as the greater of the distances in the x - coordinate direction and the y - coordinate direction from the center position of the FOV. The inspection points are arranged in ascending order according to the inspection point distance, and it is determined whether to perform or skip the inspection based on the set threshold. For example, when the inspection point ratio ratio IT is set to 0.8, for the inspection points up to the z m ×0.8 - th (the inspection points 301 located inside the inspection boundary 500) of the inspection points within the FOV where the x - coordinate or y - coordinate is closer to the center position of the FOV, the inspection is performed, and for the other inspection points (the inspection points 301 located outside the inspection boundary 500), it is determined to skip the inspection.

[0040] Note that the inspection point selection rules are not limited to the above description, and other methods are conceivable, such as skipping the inspection points at arbitrary positions (e.g., the upper half or the lower - right region, etc.) within the FOV or simply randomly selecting inspection points within the FOV.

[0041] (Extraction condition setting unit 105) FIG. 6A shows an example of information for assisting the user in setting extraction conditions, which is displayed by the extraction condition setting unit 105 on the display device 121. As the assistance information, for the inspection points defined in the grouping data 111, the first information based on the number of FOV movements (FOV movement ratio ratio FOV) and the second information based on the number of inspection points (inspection point ratio ratio IT ) and the total number of inspection points actually inspected (actual inspection point total ratio ratio IT × num IT ) are shown as a graph. The markers of the graph respectively correspond to the extraction conditions for extracting the inspection points actually inspected from the inspection points defined in the grouping data 111. Furthermore, the label of the marker displays the inspection time ratio. Here, the inspection time ratio is the ratio of the total inspection time T all required when inspecting all the inspection points defined in the grouping data 111 to the total inspection time T required when inspecting the inspection points extracted under a predetermined condition.

[0042] The support information shown in FIG. 6A means that even if the actual inspection point total ratio ratio IT × num IT is the same, there are different extraction conditions for the number of FOVs or the number of FOV movements, the number of inspection points, and the inspection time. The user can select the extraction conditions that meet the desired inspection conditions from the first information, the second information, and the third information based on the inspection time (inspection time ratio). Note that the display method of this support information is not limited to the illustrated one. The first information, the second information, and the third information may be the number of FOVs or the number of FOV movement times, the number of inspection points actually inspected in the FOV, and the inspection time, respectively. The three pieces of information represented by the two axes and the label of the marker may be interchanged, or may be represented by a three-dimensional graph. The label of the marker may be subdivided or displayed with a smooth color change.

[0043] FIG. 6B is an example of another display method of the support information shown in FIG. 6A. In this way, by displaying in a list, it becomes possible to confirm detailed numerical data. It may be configured such that the display can be switched between FIG. 6A and FIG. 6B by the display switching button 601. The user can select the desired extraction conditions with the pointer 600 on the screen shown in FIG. 6A or FIG. 6B.

[0044] Figures 7A and 7B are another example of information for assisting the user in setting extraction conditions, which is displayed by the extraction condition setting unit 105 on the display device 121. Chip patterns are repeatedly formed on the wafer to be inspected. In this example, a layout diagram is displayed that schematically shows the pattern under inspection 701 corresponding to the inspection points on the chip pattern 700. FIG. 7A shows a state in which all the patterns under inspection 701 on the chip pattern 700 are the inspection targets. That is, it corresponds to the case of inspecting all the inspection points defined in the grouping data 111. In addition to the layout diagram, an inspection time estimate 710 is shown. Here, the inspection time estimate 710 is shown as the sum of the FOV movement time 711 required for FOV movement (corresponding to the first term on the right side of Equation (3)) and the inspection point measurement time 712 (corresponding to the second term on the right side of Equation (3)), but they may also be displayed individually. Also, although inspection points are shown in the layout diagram, FOVs may be shown instead, and whether the object to be displayed in the layout diagram is an inspection point or an FOV may be switchable by the display switch button 707.

[0045] FIG. 7B shows the screen change of FIG. 7A when the extraction conditions are set by the user on the screen of FIG. 6A or FIG. 6B. For example, the fact that the pattern 702 is not shaded indicates that it is a non-inspection pattern. Thereby, the user can confirm which pattern on the chip pattern 700 has actually been excluded from the inspection targets according to the extraction conditions. Also shown are the changes in the inspection time estimate 710 and its breakdown 711, 712. By setting the object to be displayed in the layout diagram as the FOV, it is also possible to confirm the change in the FOV.

[0046] FIG. 8A and 8B show an example of an extraction condition selection screen that the extraction condition setting unit 105 displays on the display device 121. The extraction condition selection screen 800 presents the extraction selection support information shown in FIGS. 6A, 6B, 7A, and 7B to the user side by arranging them. FIG. 8A shows the screen before the extraction conditions are selected. When the user selects a desired extraction condition using the pointer 600, the display content is updated to the state shown in FIG. 8B. In this way, when selecting the extraction conditions, it becomes possible to visually grasp the FOV and inspection points selected according to the extraction conditions, which helps the user select the extraction conditions.

[0047] (Extraction condition setting unit 105 (modified example)) As a modified example, another example of the extraction condition selection screen that the extraction condition setting unit 105 displays on the display device 121 is shown. FIG. 9A shows the support information corresponding to FIG. 6A, but the extraction conditions are reduced. For example, an example is shown in which the inspection point ratio (ratio IT ) is fixed at two values of 100% and 20%. Compared with FIG. 6A, since there are fewer extraction conditions to be calculated, the time required for the inspection time estimation unit 102 to estimate the inspection time can be significantly reduced.

[0048] An example of the extraction condition selection screen at this time is shown in FIG. 9B. The mode selection screen 910 for performing extraction condition selection can be selected by pressing either the selection button 911 or the selection button 912 for either the mode that prioritizes the FOV movement ratio (ratio FOV ) or the mode that prioritizes the inspection point ratio (ratio IT ). Note that the FOV movement ratio priority mode corresponds to the graph 901 shown in FIG. 9A, and the inspection point ratio priority mode corresponds to the graph 902 shown in FIG. 9A. Under the selected mode conditions, the inspection time ratio is selected using the slide bar 913. By using such a simplified extraction condition setting screen, the extraction conditions can be easily set without user selection errors or comparison of complex conditions.

[0049] (Inspection data extraction unit 106) When the extraction condition setting unit 105 sets any of the conditions estimated by the inspection time estimation unit 102 as the extraction condition, the inspection data extraction unit 106 extracts the inspection points extracted from the grouping data 111 under the conditions set as the extraction condition as the inspection points of the inspection data 112. The extracted inspection points are sorted in the order of execution of the inspection to become the inspection data 112.

[0050] (Inspection Data Extraction Unit 106 (Modification Example)) A modification example of the inspection data extraction unit 106 will be described. In the embodiment, an example was shown in which the FOV and inspection points to be inspected are extracted according to a certain rule. In this case, however, if the user has specific inspection points that must be inspected, there is a possibility of omission from the inspection target. To avoid this, in this modification example, an evaluation wish list 113, which is a list of inspection points that the user must inspect, is registered in the storage unit 110. The inspection data extraction unit 106 merges the list of inspection points registered in the evaluation wish list 113 with the list of inspection points extracted according to the extraction conditions set by the extraction condition setting unit 105. The list of inspection points is sorted in the order of execution of the inspection to become the inspection data 112.

Embodiment

[0051] In the first embodiment, it was described that for the inspection sequence executed by the inspection control unit 108, after the stage movement by the stage mechanism 209, the FOV is defined by fine adjustment by image shift by the deflector 204. On the other hand, in the second embodiment, the inspection sequence executed by the inspection control unit 108 is an inspection sequence in which a plurality of FOVs are defined by image shift by the deflector 204 after the stage movement by the stage mechanism 209.

[0052] FIG. 10 schematically shows the inspection sequence according to Example 2. Since image shift deflects the electron beam to change the electron beam on the sample, there is an upper limit to the deflection amount. The inspection coverage range 1000 indicates the range where the FOV can be arranged by one stage movement and image shift. Thus, the inspection coverage range 1000 defined by one stage movement includes a plurality of FOVs 300. In Example 2, after the stage movement by the stage mechanism 209, the image shift by the deflector 204 is used to move to FOV 300a, and the inspection of the inspection point 301 within FOV 300a is performed. Thereafter, the movement to FOV 300b by image shift and the inspection of the inspection point 301 within FOV 300b are performed, and subsequently, the movement to FOV 300c by image shift and the inspection of the inspection point 301 within FOV 300c are performed, and then the stage movement by the stage mechanism 209 is performed to the next stage position. If the inspection is executed for all the inspection points listed in the inspection data 112 in this series of processes, the inspection is completed.

[0053] Therefore, unlike the case of Example 1, the number of FOV movements is equal to the number of image shifts, different from the number of stage movements.

[0054] FIG. 11 is a functional block diagram of a control device 100 that determines the inspection flow of a wafer and executes the inspection by a charged particle beam device. The difference from Example 1 is that a stage selection rule setting unit 1100 is added that sets a third rule (hereinafter referred to as the "stage selection rule") for determining whether to perform or skip stage movement by adding the number of stage movements as a parameter for estimating the inspection time in the inspection time estimation unit 102. Hereinafter, the description will focus on the parts specific to Example 2.

[0055] (Inspection Time Estimation Unit 102) The inspection time estimation unit 102 estimates the inspection time using the number of FOV movements, the number of inspection points, and the number of stage movements as parameters. The formula for estimating the inspection time is as shown in, for example, Equation (4).

[0056]

Equation

[0057] Here, T is the total inspection time, t SM , t IS , t IT are, respectively, the average time taken for stage movement by the stage mechanism 209, the average time taken for image shift by the deflector 204, and the average time taken for measurement of inspection points. Also, num SM is the total number of stage movements defined in the grouping data 111. The grouping data 111 includes information on relationships such as which FOV each inspection point of the wafer is inspected within and which inspection coverage range (see FIG. 10) each FOV is included in according to the inspection sequence of Example 2. num FOV is the total number of FOVs defined in the grouping data 111. x m is a binary variable that becomes 1 or 0 depending on the selection of whether to perform or skip the m-th stage movement, y mn is a binary variable that becomes 1 or 0 depending on the selection of whether to perform or skip the n-th FOV movement (image shift) within the m-th stage movement, z mn is the number of inspection points included in the n-th FOV within the m-th stage movement, ratio IT is the ratio of the number of inspection points actually inspected among the number of inspection points included in the FOV.

[0058] Also, a m is a flag variable determined by the number of times of performing the n image shifts included in the m-th stage movement, as shown in (Equation 5).

[0059]

Equation

[0060] Here, when (Equation 6) is used to transform (Equation 4), (Equation 7) is obtained.

[0061]

Equation

[0062] Here, ratio SM is the stage movement ratio obtained by dividing the number of stage movement times to be performed by the total number of stage movements num SM . ratio FOV is the FOV movement ratio obtained by dividing the number of FOVs selected for performing FOV movement by the total number of FOVs num FOV . Also, num IT is the total number of inspection points included in the FOVs selected for performing FOV movement.

[0063] [Number]

[0064] Here, t SM , t IS , t IT are respectively values specific to the charged particle beam apparatus that performs inspections. (Equation 7) shows that, regardless of the criteria for selecting the inspection coverage range for performing stage movement, the FOVs for performing FOV movement, and the inspection points actually inspected within the FOVs, the total inspection time T is ultimately determined by the stage movement ratio ratio SM , the FOV movement ratio ratio FOV , and the inspection point ratio ratio IT . Therefore, without affecting the inspection time calculated by the inspection time estimation unit 102, it is possible to set a stage selection rule, an FOV selection rule, and an inspection point selection rule for creating desired inspection coordinate data respectively.

[0065] (Extraction condition setting unit 105) In the second embodiment, the inspection time estimation is calculated as the sum of the stage movement time required for stage movement, the FOV movement time, and the inspection point measurement time. Therefore, the inspection time estimation 710 shown in FIGS. 7A and 7B may be displayed as the total of the stage movement time (corresponding to the first term on the right side of Equation 7), the FOV movement time (corresponding to the second term on the right side of Equation 7), and the inspection point measurement time (corresponding to the third term on the right side of Equation 7). [Embodiment]

[0066] In the above embodiment, it has been described that the wafer inspection management device 140 creates the grouping data 111 and sends it to the control device 100. In contrast, in this embodiment, the control device 100 receives the transmission of the CAD data of the wafer to be inspected from the wafer inspection management device 140 and creates the grouping data.

[0067] FIG. 12 is a functional block diagram of the control device 100 that determines the inspection flow of the wafer and executes the inspection by the charged particle beam device. The CAD data 115 transmitted from the wafer inspection management device 140 to the control device 100 is stored in the storage unit 110. The inspection flow determination device of Embodiment 3 includes a CAD data input unit 1201 to which the CAD data 115 is input, and a grouping data creation unit 1202 that creates the grouping data 111 from the input CAD data 115. The created grouping data 111 may be directly input to the data input unit 101, or may be once stored in the storage unit 110 and then input from the storage unit 110 to the data input unit 101.

[0068] The grouping data creation unit 1202 extracts the coordinate data of inspection points from the CAD data 115 and groups the extracted inspection points so that at least any one of them belongs to one FOV. The grouping is performed according to an algorithm, and an example of grouping is shown in FIG. 13. Examples 1 to 3 schematically show how a plurality of inspection points 301 arranged in the same manner are grouped by the FOV 300. Example 1 is an example of grouping by arranging FOVs of a certain size uniformly without gaps so as to cover all inspection points. Inspection points belonging to the same FOV are classified into the same group, and FOVs that do not contain inspection points are deleted. In Example 1, in order to arrange the FOVs without overlap, the inspection points always belong to one FOV. Example 2 is an example of grouping all inspection points by a method of solving a set partitioning problem using FOVs of a certain size. In the optimal solution of the set partitioning problem, each inspection point is always grouped into one FOV, and the number of FOVs is also minimized. Therefore, it is possible to reduce the number of FOVs compared to Example 1. Example 3 is an example of grouping all inspection points by a method of solving a set covering problem using FOVs of a certain size. In the set covering problem, the inspection points are always grouped into one or more FOVs. For this reason, there may be inspection points that are grouped into a plurality of FOVs, such as the inspection point 301d. In such a case, different results may be obtained when inspections are performed with the FOV 300d and the FOV 300e, respectively. In order to avoid such a possibility, post-processing may be performed so that the inspection point 301d belongs to only one of the FOV 300d and the FOV 300e. In the optimization of the set covering problem, since overlap of FOVs is allowed, it is possible to further reduce the number of FOVs compared to the case of Example 2.

[0069] Fig. 14A shows an example of the data structure of the grouping data 111 created by the grouping data creation unit 1202. Fig. 14B shows an example of the arrangement of inspection points indicated by the grouping data 111 shown in Fig. 14A. The data structure of the grouping data in the first embodiment has an inspection point ID 1401 that uniquely identifies an inspection point, coordinates 1402 indicating the coordinates of the inspection point, and a FOV ID 1403 that uniquely identifies the FOV. The data structure of the grouping data in the second embodiment may further have a stage ID 1404 that uniquely identifies the inspection coverage range and an image shift ID 1405 indicating the image shift within the inspection coverage range. As described above, since the FOV is determined and the coordinates of the FOV are determined, the stage ID 1404 and the image shift ID 1405 can be set by setting the inspection coverage range so that the FOVs are grouped in the same way. Note that the inspection data 112 corresponds to data obtained by extracting inspection points to be actually inspected based on the extraction conditions from the grouping data 111 and arranging them in the order of execution of the inspection.

Explanation of Signs

[0070] 100: Control device, 101: Data input unit, 102: Inspection time estimation unit, 103: FOV selection rule setting unit, 104: Inspection point selection rule setting unit, 105: Extraction condition setting unit, 106: Inspection data extraction unit, 107: Inspection data output unit, 108: Inspection control unit, 110: Memory unit, 111: Grouping data, 112: Inspection data, 113: Evaluation wish list, 115: CAD data, 120: Input device, 121: Display device, 130: Network, 140: Wafer inspection management device, 151: Processor (CPU), 152: Memory, 153: Storage device, 154: Input I / F, 155: Output I / F, 156: Communication I / F, 157: Bus, 200: Electron microscope main body, 201: Controller group, 202: Electron source, 203: Blanker, 204: Deflector, 205: Detector, 207: Electron lens, 208: Specimen stage, 209: Stage mechanism, 300: FOV, 301: Inspection point, 400: Selection rule setting screen, 500: Inspection boundary, 600: Pointer, 601: Display switch button, 700: Chip pattern, 701: Pattern to be inspected, 702: Pattern, 707: Display switch button, 710: Inspection time estimation, 711: FOV movement time, 712: Inspection point measurement time, 800: Extraction condition selection screen, 901, 902: Graph, 910: Mode selection screen, 911, 912: Selection button, 913: Slide bar, 1000: Inspection coverage range, 1100: Stage selection rule setting unit, 1201: CAD data input unit, 1202: Grouping data creation unit, 1401: Inspection point ID, 1402: Coordinates, 1403: FOV ID, 1404: Stage ID, 1405: Image shift ID.

Claims

1. An inspection time estimating unit that estimates the inspection time required to inspect inspection points extracted under predetermined conditions from grouping data obtained by grouping inspection points of a wafer to be inspected so as to belong to at least one FOV (Field of View); An inspection data extraction unit that extracts, as inspection points of inspection data indicating inspection points actually inspected for the wafer, inspection points extracted under the condition selected based on the inspection time estimated by the inspection time estimating unit as an extraction condition; The inspection time estimating unit is an inspection flow determination device that extracts inspection points from the grouping data based on an FOV selection rule that determines whether to perform or skip FOV movement using the number of FOV movements as a first parameter, and an inspection point selection rule that determines whether to actually inspect or skip inspection points using the number of inspection points actually inspected in the FOV as a second parameter.

2. In Claim 1, The FOV selection rule rearranges the FOVs included in the grouping data in ascending or descending order according to the number of inspection points in the FOV, and determines whether to perform or skip FOV movement based on a set first threshold value. The first threshold value is set for an FOV movement ratio that is a ratio of the number of FOV movements as the first parameter to the total number of FOV movements required to inspect all inspection points included in the grouping data. The inspection flow determination device.

3. In Claim 1, The inspection point selection rule rearranges the inspection points included in the FOV in the grouping data in ascending or descending order according to the inspection point distance, and determines whether to actually inspect or skip the inspection points based on a set second threshold value. The inspection point distance is defined as the greater of the distance in the first direction from the center position of the FOV to the inspection point and the distance in the second direction orthogonal to the first direction. The second threshold value is set for an inspection point ratio that is a ratio of the number of inspection points as the second parameter to the number of inspection points included in the FOV in the grouping data. The inspection flow determination device.

4. In Claim 1, The inspection data extraction unit merges the inspection points registered in a list of predetermined inspection points with the inspection points extracted according to the extraction condition, and extracts them as the inspection points of the inspection data. The inspection flow determination device.

5. In Claim 1, An inspection flow determination device having a grouping data creation unit that extracts coordinate data of inspection points from CAD data of a wafer to be inspected, and creates the grouping data by grouping the extracted inspection points so that at least one inspection point belongs to an FOV.

6. In claim 5, The grouping data creation unit groups by arranging FOVs of a certain size without gaps and uniformly covering all the inspection points extracted from the CAD data, or by solving a set partitioning problem using FOVs of a certain size for all the inspection points extracted from the CAD data, or by solving a set covering problem using FOVs of a certain size for all the inspection points extracted from the CAD data. An inspection flow determination device.

7. In claim 1, The movement of the FOV is performed by stage movement by a stage mechanism that drives a sample stage on which the wafer is placed and image shift by a deflector that deflects an electron beam irradiated on the wafer, The inspection time estimation unit calculates the inspection time as the sum of the FOV movement time and the inspection point measurement time, The FOV movement time is calculated as the product of the total number of FOV movements required to inspect all the inspection points included in the grouping data, the FOV movement ratio which is the ratio of the number of FOV movements to the first parameter for the total number of FOV movements, and the average time required for one FOV movement. The inspection point measurement time is calculated as the product of the number of all inspection points included in the selected FOV selected according to the FOV selection rule, the inspection point ratio which is the ratio of the number of inspection points to the second parameter for the number of inspection points included in the selected FOV in the grouping data, and the average time required for measuring one inspection point. An inspection flow determination device.

8. In claim 1, The movement of the FOV is performed by stage movement by a stage mechanism that drives a sample stage on which the wafer is placed and image shift by a deflector that deflects an electron beam irradiated on the wafer to any one of a plurality of FOVs included in an inspection coverage range defined by the stage movement. The inspection time estimation unit is an inspection flow determination device that extracts inspection points from the grouping data based on a stage selection rule for determining whether to perform or skip stage movement with the number of stage movements as a third parameter.

9. In claim 8, the inspection time estimation unit calculates the inspection time as the sum of the stage movement time, the FOV movement time, and the inspection point measurement time, wherein the stage movement time is calculated as the product of the total number of stage movements required to inspect all inspection points included in the grouping data, the stage movement ratio which is the ratio of the number of stage movements as the third parameter to the total number of stage movements, and the average time required for one stage movement, the FOV movement time is calculated as the product of the total number of FOV movements required to inspect all inspection points included in the grouping data, the FOV movement ratio which is the ratio of the number of FOV movements as the first parameter to the total number of FOV movements, and the average time required for one FOV movement, the inspection point measurement time is calculated as the product of the number of all inspection points included in the selected FOV selected according to the FOV selection rule, the inspection point ratio which is the ratio of the number of inspection points as the second parameter to the number of inspection points included in the selected FOV in the grouping data, and the average time required for measuring one inspection point, and is an inspection flow determination device.

10. A charged particle optical system including a charged particle source, a stage mechanism system on which the wafer irradiated with the charged particle beam from the charged particle source is placed, a group of controllers for controlling the charged particle optical system and the stage mechanism system, the inspection flow determination device according to any one of claims 1 to 9, and an inspection control unit for controlling the group of controllers so as to inspect the inspection points of the wafer according to the inspection data. A charged particle beam device having the same.

11. In claim 10, the inspection is a dimensional measurement at the inspection point or an electrical property measurement at the inspection point. A charged particle beam device.

12. An inspection time estimation function for estimating the inspection time required to inspect inspection points extracted under predetermined conditions from grouping data obtained by grouping inspection points of a wafer to be inspected so as to belong to at least one FOV (Field of View), A program for causing a computer to implement an inspection data extraction function that extracts, as inspection points of inspection data indicating inspection points actually inspected for the wafer, inspection points extracted using, as extraction conditions, the conditions selected based on the inspection time estimated by the inspection time estimation unit. The inspection time estimation function is a program that extracts inspection points from the grouping data based on a FOV selection rule that determines whether to perform or skip FOV movement using the number of FOV movements as a first parameter, and an inspection point selection rule that determines whether to actually inspect or skip inspection points using the number of inspection points actually inspected in the FOV as a second parameter.

13. In Claim 12, Furthermore, a program for causing a computer to implement a grouping data creation function that extracts coordinate data of inspection points from CAD data of the wafer to be inspected, groups the extracted inspection points so that they belong to at least one FOV, and creates the grouping data.

14. An inspection time estimation unit that estimates the inspection time required to inspect inspection points extracted under predetermined conditions from grouping data in which inspection points of a wafer to be inspected are grouped so as to belong to at least one FOV (Field of View), an extraction condition setting unit, and an inspection data extraction unit that extracts, as inspection points of inspection data indicating inspection points actually inspected for the wafer, inspection points extracted under the extraction conditions set by the extraction condition setting unit. The inspection time estimation unit extracts inspection points from the grouping data based on a FOV selection rule that determines whether to perform or skip FOV movement using the number of FOV movements as a first parameter, and an inspection point selection rule that determines whether to actually inspect or skip inspection points using the number of inspection points actually inspected in the FOV as a second parameter. The inspection time estimation unit estimates the inspection time under a plurality of the predetermined conditions with different first parameters and / or second parameters. The extraction condition setting unit is an inspection flow determination device that displays, on a display device, first information based on the number of FOV movements as the first parameter, second information based on the number of inspection points as the second parameter, and third information based on the inspection time estimated by the inspection time estimation unit.

15. In Claim 14, The extraction condition setting unit is an inspection flow determination device configured to be able to select any one of a plurality of the predetermined conditions as the extraction condition.

16. In claim 14, the inspection time estimation unit estimates the inspection time based on a plurality of the predetermined conditions corresponding to a first parameter priority mode that prioritizes the first parameter and a plurality of the predetermined conditions corresponding to a second parameter priority mode that prioritizes the second parameter, the extraction condition setting unit is an inspection flow determination device that displays the first information, the second information, and the third information on a display device for each of the first parameter priority mode and the second parameter priority mode.

17. In claim 16, the extraction condition setting unit is an inspection flow determination device configured to be able to select either the first parameter priority mode or the second parameter priority mode as the extraction condition.

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