Electrical characteristic evaluation method, electrical characteristic evaluation apparatus, and electrical characteristic evaluation system

Abstract

The purpose of the present disclosure is to use the results of evaluation of the electrical characteristics of an element manufactured in an interim step of manufacturing steps for a semiconductor device to evaluate the electrical characteristics of the semiconductor device as a whole. In the disclosed electrical characteristic evaluation method, results of evaluation of the electrical characteristics of a semiconductor element formed in an interim step in the manufacturing of a semiconductor device are accepted and, after a second equivalent circuit of the semiconductor device is reflected in a first equivalent circuit of the semiconductor device, the electrical characteristics of the semiconductor element are used to simulate the electrical characteristics of the first equivalent circuit (see FIG. 1).

Description

Electrical characteristic evaluation method, electrical characteristic evaluation device, and electrical characteristic evaluation system

[0001] The present disclosure relates to a technique for evaluating the electrical characteristics of a semiconductor device.

[0002] Japanese Patent Application Laid-Open No. 2003-144994 (Patent Document 1) describes a charged particle beam device for estimating electrical characteristics, such as capacitance characteristics, of a sample. The document states the following: "The comparator 230 compares the calculation results stored in the estimated irradiation result storage unit 228 (i.e., the calculation results by the emission amount calculation unit 227) with the actual measurement results stored in the electron beam irradiation result storage unit 229 (i.e., the actual measurement results by the detector 219). If the comparator 230 obtains a mismatched comparison result, the calculation netlist update unit 226 updates the element parameter values ​​in the calculation netlist, and the above-described process from the emission amount calculation unit 227 to the comparator 230 is performed again using the updated calculation netlist. On the other hand, if the comparator 230 obtains a matched comparison result, the calculation netlist update unit 226 stores the netlist containing the current element parameter values ​​as an estimated netlist in the estimated netlist storage unit 231" (paragraph 0034).

[0003] Patent No. 7250642

[0004] Patent Document 1 creates a netlist describing the components of an equivalent circuit of a semiconductor device, and reflects the results of measuring electrical characteristics such as capacitance in the netlist. The measurement technology described in Patent Document 1 can measure the capacitance of a semiconductor element formed inside a sample in the height direction, as shown in, for example, Figure 3A of the document. This semiconductor element is manufactured in an intermediate step in the process of manufacturing the entire semiconductor device. In other words, Patent Document 1 can be said to be a technology for measuring the electrical characteristics of an element manufactured in an intermediate step in semiconductor device manufacturing. Therefore, the electrical characteristics reflected in the netlist in Patent Document 1 are also the electrical characteristics of an element manufactured in such an intermediate step.

[0005] On the other hand, the electrical characteristics of a finished semiconductor device can be evaluated by, for example, contacting a tester probe with a measurement pad to input an input signal and measuring the response as an output signal. Alternatively, the electrical characteristics of the semiconductor device can be evaluated by simulating an equivalent circuit of the same semiconductor device using a SPICE simulator or the like and comparing the result with a reference value.

[0006] A SPICE simulator simulates an equivalent circuit of a semiconductor device based on design data for the semiconductor device. This is useful as a method for evaluating the electrical characteristics of a finished semiconductor device. Meanwhile, it is desirable to be able to evaluate the electrical characteristics of an element manufactured during a semiconductor device manufacturing process to determine whether the element is suitable for proceeding to subsequent processes (i.e., whether the element resulting from the process is a good product). Patent Document 1 can evaluate the electrical characteristics of such an element. However, this evaluation is not an evaluation of the finished semiconductor device, but rather an evaluation of the electrical characteristics of the element itself. In other words, even if Patent Document 1 evaluates the electrical characteristics of an element, it does not necessarily fully consider how the electrical characteristics are reflected in the electrical characteristics of the finished semiconductor device.

[0007] The present disclosure has been made in consideration of the above-mentioned problems, and aims to evaluate the electrical characteristics of an entire semiconductor device using the results of evaluating the electrical characteristics of an element manufactured in an intermediate step in the manufacturing process of the semiconductor device.

[0008] The electrical characteristic evaluation method disclosed herein receives the results of evaluating the electrical characteristics of a semiconductor element formed during a manufacturing process of a semiconductor device, reflects a second equivalent circuit of the semiconductor element in a first equivalent circuit of the semiconductor device, and then simulates the electrical characteristics of the first equivalent circuit using the electrical characteristics of the semiconductor element.

[0009] According to the electrical characteristic evaluation method of the present disclosure, the electrical characteristics of the entire semiconductor device can be evaluated using the results of evaluating the electrical characteristics of an element manufactured in an intermediate step of the manufacturing process of the semiconductor device. Other objects, configurations, advantages, etc. of the present disclosure will become apparent with reference to the following embodiments.

[0010] FIG. 1 is a diagram showing an overview of an electrical characteristic evaluation system including a measurement tool capable of measuring the characteristics of electrical elements included in a semiconductor wafer during a device manufacturing process. FIG. 2 is a graph showing changes in brightness of an SEM image with respect to changes in the interruption time (time when the pulsed beam is not irradiated) when a pulsed electron beam is irradiated. FIG. 3 is a schematic side cross-sectional view showing the relationship between a first equivalent circuit 310 and a second equivalent circuit 320. FIG. 4 is a diagram showing an output signal obtained from an electrical pad 312 when a predetermined signal is supplied to an electrical pad 311. FIG. 5 is a flowchart showing a part of a semiconductor device manufacturing process including a semiconductor device design process. FIG. 6 is a process flow diagram of an electrical characteristic evaluation system. FIG. 7 is a process flow diagram of an electrical characteristic evaluation system. FIG. 8 is a process flow diagram of an electrical characteristic evaluation system. FIG. 9 is an example of a user interface provided by the electrical characteristic evaluation system.

[0011] <Background of the present disclosure> With regard to process management of wafers in the middle of a semiconductor device manufacturing process, it is conceivable to budget the shape (CD value (average value, variation), roughness value, etc.) and defect density specifications in each process and determine pass / fail at each process so that the electrical characteristics (including reliability and yield) specifications of wafers in the final device manufacturing process are satisfied.

[0012] Meanwhile, as one type of verification of device operation principles, such as determining what layout and what processes are required to output the desired device operation (electrical characteristics), there is an Electronic Design Automation (EDA) tool that simulates everything from design data to electrical characteristic output. Effective use of such EDA tools makes it possible to quickly launch and stably operate a semiconductor device manufacturing system. Furthermore, if defects can be detected at each process before proceeding to the final process, feedback can be provided to the manufacturing process promptly.

[0013] As device structures become more three-dimensional, device structures become more complex and holes become deeper in the Z direction. Therefore, the risk of overlooking defects increases when only shape control using a CD SEM (Critical Dimension Scanning Electron Microscope) for patterns in each process can result in yield loss. Therefore, it is desirable to determine the pass / fail of each process using a separate means that is highly sensitive in the Z direction. In particular, if the electrical features required for electrical elements can be evaluated, the previously described overlooking of defects can be prevented.

[0014] A netlist is design data that represents electrical elements (components) that make up an electrical circuit, such as resistors, capacitors, inductors, transistors, and power supplies. Such netlists are sometimes used as input data for integrated circuit (IC) design simulations. IC design simulations are performed to analyze the netlist and determine how the circuit will operate. Semiconductor devices are manufactured through multiple manufacturing processes, and some IC design simulations evaluate the electrical characteristics of devices manufactured through multiple manufacturing processes.

[0015] The component specifications included in the netlist used in the simulation are usually derived from design data, but if it were possible to perform a simulation of electrical characteristics to be evaluated in the final process, for example, based on electrical characteristics (specifications) that can be obtained by actual measurements as the device is being manufactured, it would be possible to evaluate the performance of the semiconductor device, which is affected by process variations that occur over time or unexpectedly, before the semiconductor device reaches the final process. This would enable rapid feedback to the manufacturing process.

[0016] Below, we will explain in detail, using drawings, a method for estimating electrical characteristics that can be obtained in the final process based on the setting of specifications for a specific element that can be obtained in intermediate processes up to the final process, a computer-implemented method, a computer program, a non-transitory recording medium, an apparatus, and a system.

[0017] As one mode for achieving the above object, we propose a method characterized by converting "output results such as resistance values ​​and capacitance values ​​of electrical elements contained in wafers actually measured during device manufacturing processes" into "electrical characteristics (IV, Vth, frequency characteristics, etc.) output by a tester on a wafer in the final process of device manufacturing," and outputting the results. With such a method, it becomes possible to predict the output results of an electrical tester, etc., based on actual measurements during the manufacturing process.

[0018] 1 is a diagram illustrating an electrical characteristic evaluation system including a metrology tool capable of measuring the characteristics of electrical elements included in a semiconductor wafer during device manufacturing. The system illustrated in FIG. 1 includes a design data storage medium 101 storing integrated circuit layout data and / or symbolic data formats (e.g., GDSII (GDS2), GL1, OASIS, map files, or other formats for storing design data structures), an EDA tool 102, an electrical characteristic measurement device (electrical characteristic measurement tool) 103, and one or more computer systems 104. The system illustrated in FIG. 1 may also be connected to other metrology devices 105, such as an optical inspection device, an optical critical dimension (OCD), a CD-SEM, or an electron beam inspection (EBI) device. These devices (tools) are connected to each other via a bus 106 for mutual communication.

[0019] 1 includes one or more computer systems 104, and the EDA tool 102 may include software for performing simulations (described later) and for calculating the electrical characteristics of electrical circuits included in semiconductor wafers, a storage medium for storing the software, and one or more computer systems each equipped with one or more processors for executing the software. Each device constituting the system may be equipped with a computer system, or multiple devices may be controlled by a single workstation.

[0020] The electrical characteristic measuring device 103 includes a charged particle beam device (evaluation unit) including a beam column for irradiating a sample with a beam (e.g., an electron beam) and a detector for detecting secondary electrons (SE) and / or backscattered electrons (BSE) obtained by irradiating the sample with the beam. In this embodiment, as an example of the electrical characteristic measuring device 103, an example is described in which the resistance value, capacitance value, etc. of an electrical element are derived based on brightness information (gray level) obtained by the charged particle beam device. However, this is not limited to this, and other derivation methods for determining resistance values ​​and capacitance values ​​based on output information obtained based on some input may also be applied. In this case, a model defining the relationship between image information or detection signals and electrical characteristics may be stored in a predetermined storage medium in advance, and the electrical characteristics may be derived using the model by one or more processors. The model may include a mathematical model, a database, a trained model trained by machine learning, etc.

[0021] When a charged particle beam device is used as the electrical characteristic measuring device 103, a method may be adopted in which a beam is irradiated in a spot shape onto a specific element on the sample (such as a plug visible on the wafer surface), thereby electrically connecting the specific element to the element and applying a predetermined charge to an electrical element having one end grounded, and measuring its brightness.

[0022] The beam column of the charged particle beam device may be equipped with a lens (e.g., an electromagnetic lens) for focusing the beam into a spot and a deflector for adjusting the beam irradiation position. Furthermore, as described below, a blanking deflector for irradiating the beam in pulses onto the target sample may be equipped. The blanking deflector deflects the beam off-axis to prevent the beam from reaching the sample. The beam may be irradiated in pulses onto the sample by repeatedly turning the deflection by the blanking deflector on and off. The charged particle beam device may be equipped with one or more computer systems (controllers) for controlling optical elements such as lenses.

[0023] Furthermore, the electrical characteristic measuring device 103 may have a built-in storage medium that stores an application for evaluating the electrical characteristics of circuit components connected to terminals such as plugs that are irradiated with the beam, based on the detector output.

[0024] The electrical characteristic measuring device 103 is also equipped with a charge supply tool for applying a predetermined charge to an object whose electrical characteristics are to be measured. The charge supply tool includes, for example, a laser light source, and supplies a predetermined charge to the object by irradiating the object with a laser. With the charge supplied, the object is irradiated with a pulsed electron beam to perform the electrical characteristic evaluation described below.

[0025] Figure 2 is a graph showing the change in brightness of an SEM image with respect to the interruption time (time when the pulsed beam is not irradiated) when a pulsed electron beam is irradiated. The left side of Figure 2 shows the change in brightness with respect to the interruption time of a capacitance-based defect, and the right side of Figure 2 shows the change in brightness with respect to the interruption time of an electrical resistance-based defect.

[0026] As shown in Fig. 2, there is a difference in the characteristics of the change in brightness when the interruption time is changed between an electrical resistance defect and a capacitance defect. Therefore, it is possible to determine whether the defect is a capacitance defect or an electrical resistance defect based on the difference in such characteristics.

[0027] For capacitance-based defects, the difference in brightness for each capacitance tends to become more pronounced as the interruption time increases. By utilizing this characteristic, the defect type may be determined, for example, from the difference between the brightness in an area with a long interruption time and the average brightness (average brightness of different capacitance defects) previously registered in the area with a long interruption time. In this case, for example, if the difference exceeds a predetermined threshold, the defect may be determined to be a capacitance-based defect, and if the difference is equal to or less than the predetermined threshold, the defect may be determined to be an electrical resistance-based defect.

[0028] For electrical resistance defects, the difference in brightness for each electrical resistance tends to become more apparent as the interruption time becomes shorter. By utilizing this characteristic, the defect type may be determined, for example, from the difference between the brightness in an area with a short interruption time and the average brightness (average brightness of different electrical resistance defects) previously registered in the area with a short interruption time. In this case, for example, if the difference exceeds a predetermined threshold, the defect may be determined to be an electrical resistance defect, and if the difference is equal to or less than the predetermined threshold, the defect may be determined to be a capacitance defect.

[0029] Alternatively, the obtained curve may be fitted to a curve showing the relationship between the change in the interruption time and the change in brightness, which is stored in advance for each defect type, and the defect type may be classified according to the degree of agreement.Furthermore, it is also conceivable to prepare (store) in advance a plurality of curves corresponding to a plurality of capacitances and a plurality of curves corresponding to a plurality of electrical resistances, and estimate the capacitance or electrical resistance according to the degree of agreement.

[0030] The electrical resistance value and capacitance value may be derived by inputting luminance information into, for example, Equation 1, a mathematical model obtained by modifying it, a database, or a model trained with a data set of luminance information and electrical property information. S is luminance, C is capacitance, R is electrical resistance, Q is charge accumulated in the sample by beam irradiation, Ti1 is the first beam interruption time for the sample of the pulsed beam, which is the first beam irradiation condition, Ti2 is the second beam interruption time for the sample of the pulsed beam, which is the second beam irradiation condition, and Tir is the beam irradiation time.

[0031]

[0032] A computer system that stores Equation 1, a variant of Equation 1, or a mathematical model corresponding to Equation 1 derives electrical characteristics such as capacitance C and resistance R based on difference information (ΔS) in brightness obtained when two types of pulse beams with different beam interruption times are irradiated. This method is merely one example, and other methods for deriving electrical characteristics such as those described above may be used based on measurements that allow modeling of relationships with electrical characteristics or on receipt of inspection tool output information.

[0033] The EDA tool 102 is software that automatically performs semiconductor device design, design support, or analysis of the operation of a semiconductor device, or one or more computer systems for executing that software.

[0034] The EDA tool 102 automatically performs support for semiconductor device design, etc., based on input of semiconductor device design data, product ideas, specifications, etc. The EDA process using the EDA tool 102 includes, for example, system design, logic design, function verification, test data synthesis and design, netlist verification, design planning, physical implementation, analysis and extraction of circuit functions at the layout level, physical verification, layout geometry change (adjustment), and mask data preparation.

[0035] The EDA process of the EDA tool 102 may include a process for estimating the electrical output characteristics of a semiconductor device at the final stage of the semiconductor manufacturing process (pre-process). Furthermore, in addition to the EDA process, simulations may be performed during the semiconductor device manufacturing process, and feedback and / or feedforward may be performed on the semiconductor manufacturing process based on the results of the simulation. As described below, this embodiment may include a process for importing electrical characteristics of a small-scale circuit that can be obtained during the semiconductor device manufacturing process, for example, and simulating the electrical output characteristics of the semiconductor device at the final stage.

[0036] To perform the above-described simulation, the EDA tool 102 acquires information about circuits generated from bare wafers through to the final process, and electrical characteristic information about the small-scale circuit in the current process. The EDA tool 102 generates a netlist that includes some actual measured values ​​by replacing some information in a netlist generated from design data or the like with information obtained by the electrical characteristic measuring device 103, and may be provided with an internal or external storage medium for storing software or an application capable of executing a process for simulating the electrical output characteristics of the semiconductor element in the final stage based on the netlist or the like, and may perform the above-described simulation.

[0037] 3 is a schematic cross-sectional side view showing the relationship between a first equivalent circuit 310 and a second equivalent circuit 320. The first equivalent circuit 310 is an electric circuit to be evaluated by an electric tester for a "wafer in the final stage of device manufacturing." The second equivalent circuit 320 is an electric circuit or electric element to be evaluated by an electric characteristic measuring apparatus 103 for a "wafer in the middle stage of device manufacturing."

[0038] A semiconductor device includes electrical elements belonging to multiple layers that make up an electrical circuit, and a multilayer structure is formed on an unprocessed wafer (bare wafer) through multiple manufacturing processes. A semiconductor device that has reached the final stage may be provided with electrical pads 311 (input) and 312 (output), etc., whose electrical characteristics can be measured by contact with a probe or the like. By monitoring the output signal (voltage) when a predetermined input signal (current) is supplied to these electrical pads, the quality of the semiconductor device or the appropriateness of the manufacturing process can be determined.

[0039] Electrical elements 321 and 322 are formed inside the semiconductor device in the height direction. These electrical elements are manufactured during an intermediate step in the semiconductor device manufacturing process. When test probes are brought into contact with electrical pads 311 and 312 to measure output signals, the electrical characteristics of the entire semiconductor device, including these internal electrical elements, are measured. On the other hand, when measuring the electrical characteristics of electrical elements 321 and 322, the electrical characteristics are measured using electrical characteristic measuring apparatus 103 during an intermediate step in the semiconductor device manufacturing process (i.e., the stage at which electrical elements 321 and 322 are formed during the stacking process).

[0040] When the electrical characteristic measuring device 103 measures the electrical characteristics of the electrical elements 321 and 322, the electrical characteristics are acquired by irradiating a charged particle beam onto these elements after grounding them, as described in, for example, Patent Document 1. Therefore, the second equivalent circuit is also described assuming that these elements are grounded. In contrast, because semiconductor devices are not necessarily measured by a tester in a grounded state, the first equivalent circuit does not need to include a ground.

[0041] 4 is a diagram showing an output signal obtained from electrical pad 312 when a predetermined signal is supplied to electrical pad 311. The upper part of Fig. 4 shows the output signal when the electrical circuit connected to the electrical pad is normal, while the lower part of Fig. 4 shows an example of the output signal when some kind of abnormality exists in the electrical circuit.

[0042] If such an output signal can be obtained before the final step of the device manufacturing process, it can be quickly fed back to the semiconductor manufacturing process. In this embodiment, an example will be described in which the output signal as shown in FIG. 4 is derived by calculation (simulation) rather than by actual measurement.

[0043] FIG. 5 is a flowchart showing a part of the manufacturing process of a semiconductor device, including the design process of the semiconductor device.

[0044] Step S501: In the EDA process, the EDA tool 102 receives design data created in a format for storing a design data structure, schematic data for representing the arrangement and connection of components that make up an electric circuit on a layout, and a PDK (Process Design File), which is a design information file used when designing a circuit using a specific semiconductor process.

[0045] Step S502: One or more computer systems (processors) included in the EDA tool 102 generate three-dimensional structure (3D layout) data of the semiconductor device based on the received data.

[0046] Steps S503 to S504: The first or more computer systems create a process flow based on the generated 3D layout data, and also generate an equivalent circuit to be used in a subsequent simulation.

[0047] Step S505: By generating the process flow and equivalent circuit, the manufacturing process and its coordinates to be measured by the electrical characteristic measuring device 103 become clear, so the electrical characteristic measuring device 103 may create a measurement flow based on the process flow data.

[0048] Step S506: In the EDA process, one or more computer systems create a device model to be used in the circuit analysis in S507 (described later). The device model is, for example, an analytical formula, and the model creation involves creating and setting this analytical formula and model parameters such as variables and constants included in the analytical formula.

[0049] Step S507: One or more computer systems generate an equivalent circuit for the entire circuit, including the layer to be measured, and then perform a circuit simulation such as SPICE (Simulation Program with Integrated Circuit Emphasis) based on the equivalent circuit. The circuit simulation is performed, for example, in the following order: circuit description, circuit analysis, and analysis result output. Here, for example, a circuit diagram input using a circuit diagram editor is converted into a netlist, which is then passed to an analysis engine for automatic simulation.

[0050] Step S508: The one or more computer systems calculate the electrical characteristics by circuit simulation, store the derived electrical characteristic information in a predetermined storage medium, and determine whether the circuit design is appropriate based on the suitability of the derived electrical characteristics, and update the design data, etc. as necessary.

[0051] After going through the semiconductor design process described above, the process moves to the manufacturing (mass production) stage of semiconductor devices. In the mass production process, it is desirable to appropriately evaluate process variations of semiconductor devices and to provide feedback / feedforward to the manufacturing process. Therefore, in this embodiment, an example of implementing process management in the mass production stage using a simulation model generated in the EDA process will be described.

[0052] In this embodiment, an example will be described in which data relating to a circuit simulator, a model, an equivalent circuit, etc. generated in an EDA process is imported into an EDA tool or a computer system in which a predetermined program is stored. However, the present invention is not limited to this. In the mass production process, a circuit simulator, a model, an equivalent circuit, etc. may be newly created using an EDA tool or another computer system, and the processing described below may be performed based on the obtained equivalent circuit, etc.

[0053] Step S509: In the measurement process of semiconductor devices included in the mass production process, measurements are performed using the electrical characteristic measuring device 103. In the measurement process illustrated in FIG. 5, first, electrical characteristic output information obtained in the EDA process is received. In the EDA process, electrical characteristics when the device is normal are obtained by simulation for proper design, so reference information is created based on this data. Here, the electrical characteristics obtained by simulation are received, and a reference range (normal range) is set with the electrical characteristics as normal values. The information used as reference information is not limited to information obtained by simulation, and may be, for example, actual measured values ​​of the reference location or other appropriate reference values.

[0054] Step S510: After the above preparations, measurements are performed on the semiconductor wafers manufactured in the mass production process. Next, electrical characteristics are measured based on beam irradiation of the object of electrical characteristics evaluation or the terminals (plugs, etc.) connected to the object of evaluation.

[0055] Step S511: The EDA tool 102, one or more computer systems built into the electrical characteristic measuring device 103, or another computer system (e.g., computer system 104) communicatively connected to the electrical characteristic measuring device 103 receives electrical characteristic measurement results of an electrical element during the manufacturing process of a semiconductor device, such as capacitance value, resistance value, etc. The computer system may receive electrical characteristic information determined by another computer system, or may receive output from a detector built into the electrical characteristic measuring device 103, calculate electrical characteristic information based on the detector output, and then perform the processing described below.

[0056] Step S512: The EDA tool 102 or the like receives a device model to be used for circuit simulation. This device model will be described as being generated by the EDA process, but this is not limiting. A device model whose parameters are updated based on other measurement results or the like may be created in the mass production process.

[0057] Step S513: The EDA tool 102 or the like updates the device model by importing the measurement results of a specific element into the device model. For example, the electrical characteristics of the second equivalent circuit included in the first equivalent circuit are replaced with the electrical characteristic measurement values ​​from S510. A GUI (Graphical User Interface) screen is provided that displays both the netlist corresponding to the first equivalent circuit and the measurement results (measurement results of the second equivalent circuit) from the electrical characteristic measurement device 103. This allows selective import of any of the multiple electrical characteristic measurement results obtainable in each manufacturing process, thereby enabling simulations to be performed according to the performance of electrical elements measurable in different manufacturing processes. The GUI can be provided, for example, by the computer system 104.

[0058] Steps S514 to S515: The EDA tool 102 or the like outputs electrical characteristics (I-V, Vth, frequency characteristics, etc.) by, for example, executing a SPICE simulation (S514) based on the device model into which the actual measurement values ​​have been partially imported in S513. The output electrical characteristics are derived from a device model whose parameters have been updated using actual measurement values ​​that can be obtained during the semiconductor device manufacturing process. Therefore, they can serve as a basis for determining the suitability of the device for the final process before it reaches the final process.

[0059] Steps S516 to S518: The output electrical characteristics are compared with the reference information acquired in step S509 (S516). Based on this comparison, a defect determination is performed (S517). The defect determination result is fed back to the manufacturing process (S518).

[0060] Fig. 6 is a process flow diagram of an electrical characteristic evaluation system. The EDA tool 102, electrical characteristic measurement device 103, and computer system (including computer system 104) that controls them, which implement the flowchart described in Fig. 5, can be configured as an electrical characteristic evaluation system that evaluates the electrical characteristics of semiconductor devices. Fig. 6 corresponds to a visual redrawing of the processing procedure of the flowchart in Fig. 5.

[0061] The EDA tool 102 receives design data, schematic data, PDK, etc. (S501) and uses them to create 3D layout data (S502). The EDA tool 102 creates a process flow based on the 3D layout data (S503). The EDA tool 102 identifies measurement target layers and measurement target locations of the semiconductor device and creates an equivalent circuit for them (S504-S505). The measurement target here is the second equivalent circuit described in FIG. 3. The EDA tool 102 creates a SPICE simulation model of the equivalent circuit for the final process (corresponding to the finished semiconductor device) (S506).

[0062] On the other hand, the electrical characteristic measuring device 103 measures the electrical characteristics of the semiconductor element (corresponding to the second equivalent circuit) (S510) and returns the results to the EDA tool 102 (S513).

[0063] The EDA tool 102 reflects the electrical characteristics of the semiconductor element (second equivalent circuit) measured by the electrical characteristic measuring device 103 in the SPICE simulation model (S513). The EDA tool 102 uses the reflected results to simulate the entire semiconductor device (i.e., the first equivalent circuit) to calculate electrical characteristics (S514) and outputs the results (S515). Based on the results, the electrical characteristic measuring device 103 determines whether or not there is a defect at the measurement point (S516 to S517).

[0064] FIG. 7 is a process flow diagram of the electrical characteristic evaluation system. While FIG. 6 illustrates the electrical characteristic measurement device 103 and the computer system 104 as a single entity, FIG. 7 illustrates them separately. The electrical characteristic measurement device 103 creates an SEM image of a semiconductor device being manufactured in an intermediate process by irradiating the semiconductor device with a charged particle beam. The computer system 104 creates a measurement recipe and a netlist of a second equivalent circuit, and uses these to control the process of acquiring the SEM image. The computer system 104 uses the SEM image and the netlist of the second equivalent circuit to calculate the electrical characteristics (resistance and capacitance) of the second equivalent circuit and output the results to the EDA tool 102.

[0065] The EDA tool 102 reflects the electrical characteristics of the second equivalent circuit in the netlist of the first equivalent circuit and then performs a SPICE simulation using the netlist. This allows the EDA tool 102 to simulate the electrical characteristics of the first equivalent circuit (i.e., the entire semiconductor device) after incorporating the results of measuring the electrical characteristics of the second equivalent circuit (i.e., the semiconductor element created during the manufacturing process) by the electrical characteristic measuring device 103. Determination conditions for determining whether or not there is a defect in the first equivalent circuit are prepared in advance during the manufacturing process and provided to the computer system 104, allowing the computer system 104 to determine whether or not there is a defect based on the results of the SPICE simulation. The computer system 104 outputs the determination results and, as necessary, can provide feedback on the cause of the defect, etc., to the manufacturing process.

[0066] FIG. 8 is a process flow diagram of the electrical characteristic evaluation system. FIG. 7 shows the process flow when measuring electrical characteristics of a measurement target location on a specific measurement target layer. In other words, FIG. 7 is for obtaining measurement results only for a specified location. In contrast, FIG. 8 is for more comprehensively inspecting whether a target area on a specified target layer is good or bad. Therefore, since the electrical characteristic measuring device 103 operates as an electrical characteristic inspection device, it is represented as such in FIG. 8.

[0067] The computer system 104 measures the electrical characteristics of the designated area and determines whether the designated area is good or bad based on the results. The EDA tool 102 imports the electrical characteristics of the designated area and simulates the electrical characteristics of a first equivalent circuit. The computer system 104 determines whether the first equivalent circuit is good or bad based on the simulation results.

[0068] 9 shows an example of a user interface provided by the electrical characteristic evaluation system. This user interface can be provided as a GUI in the computer system 104, for example. The user selects one or more components included in the first equivalent circuit on the UI and instructs execution of a simulation. The EDA tool 102 performs a simulation using the selected components and the results of measurements of the electrical characteristics of the electrical elements previously performed by the electrical characteristic measuring device 103. The electrical characteristics of the electrical elements may also be presented. The UI may also present the Pass / Fail or good / bad product judgment results described in FIG. 7 together with the simulation results.

[0069] <Regarding Modifications of the Present Disclosure> In the above embodiment, when the EDA tool 102 imports the results of measuring the electrical characteristics of the electrical elements 321 and the like by the electrical characteristic measuring device 103, the electrical characteristic measuring device 103 outputs the electrical characteristics of the electrical elements 321 and the like and the netlist of the second equivalent circuit in a data format that can be imported by the EDA tool 102. The EDA tool 102 integrates these with the netlist of the first equivalent circuit. The specific data format and integration process may be determined appropriately depending on the specifications of the EDA tool 102. Alternatively, the electrical characteristic measuring device 103 may output a general-purpose data format, such as text data, and a data format conversion process may be interposed between the electrical characteristic measuring device 103 and the EDA tool 102 to enable data exchange between the two. In either case, the electrical characteristic measuring device 103 outputs the electrical characteristics of the electrical elements 321 and the netlist of the second equivalent circuit in a data format that can ultimately be imported by the EDA tool 102.

[0070] In the above embodiments, the processing flows described in Figures 5 to 8 can be implemented by a computer system (e.g., computer system 104) executing a program that implements the processing flows. The program may be configured as a single program module, or may be divided into multiple program modules. Each program module may be located on the same computer system, or any program module may be distributed across two or more computer systems.

[0071] In the above embodiments, the computer system 104 or an equivalent computer system may be provided for each of the EDA tool 102, the electrical characteristic measuring device 103, and the measuring device 105, or two or more of these may be controlled by a single computer system.

[0072] In the above embodiment, the electrical characteristic measuring device 103 has been described as measuring or inspecting the electrical characteristics of semiconductor elements manufactured during the manufacturing process of semiconductor devices, depending on the purpose of the electrical characteristic evaluation system. The electrical characteristic measuring device 103 is not limited to this, and can also perform general evaluation of the electrical characteristics of semiconductor devices. Evaluation here includes measurement, inspection, and any other process that acquires the physical state of a semiconductor device. Therefore, the electrical characteristic measuring device 103 more generally functions as an electrical characteristic evaluation device.

[0073] 101: Design data storage medium 102: EDA tool 103: Electrical characteristic measuring device 104: Computer system 105: Measuring device

Claims

1. An electrical characteristic evaluation method for evaluating electrical characteristics of a semiconductor device, comprising the steps of: obtaining a first list describing components that configure a first equivalent circuit of the semiconductor device including a semiconductor element formed in an intermediate step of a manufacturing process for manufacturing the semiconductor device; simulating the electrical characteristics of the first equivalent circuit using the first list; and evaluating the electrical characteristics of the semiconductor device based on a result of the simulation, wherein the simulating step further comprises a step of obtaining a second list describing components that configure a second equivalent circuit of the semiconductor element formed in the intermediate step; and the simulating step further comprises a step of obtaining a result of evaluating the electrical characteristics of the semiconductor element using the second equivalent circuit, wherein the simulating step integrates the second equivalent circuit described by the second list into the first equivalent circuit described by the first list, and wherein the simulating step performs the simulation using the electrical characteristics of the semiconductor element to simulate the electrical characteristics of the first equivalent circuit including the second equivalent circuit.

2. The electrical characteristic evaluation method according to claim 1, characterized in that the results of evaluating the electrical characteristics of the semiconductor element are evaluated by detecting secondary charged particles generated by irradiating the semiconductor element with a charged particle beam.

3. The electrical characteristic evaluation method according to claim 1, characterized in that the first equivalent circuit does not have a ground potential, and the second equivalent circuit has a ground potential connected to the semiconductor element.

4. The electrical characteristic evaluation method according to claim 1, characterized in that the electrical characteristics of the semiconductor element are at least one of the electrical resistance of the semiconductor element or the electrostatic capacitance of the semiconductor element, and in the simulating step, the simulation is performed using at least one of the electrical resistance of the semiconductor element or the electrostatic capacitance of the semiconductor element acquired in the step of acquiring the electrical characteristics of the semiconductor element.

5. The electrical characteristic evaluation method according to claim 1, characterized in that the manufacturing process is configured to form the semiconductor element by stacking a plurality of layers in the height direction of the semiconductor device, and the simulating step simulates the electrical characteristics of the first equivalent circuit by simulating a response obtained by inputting an electrical signal from a surface of the semiconductor device.

6. The electrical characteristic evaluation method according to claim 5, wherein the semiconductor device comprises an input pad for inputting the electrical signal from a tester to the semiconductor device, and an output pad for outputting the response from the semiconductor device to the tester, and the electrical characteristic evaluation method further comprises a step of evaluating the electrical characteristics of the semiconductor device by comparing the response measured using the tester with the result of the simulation.

7. The electrical characteristic evaluation method according to claim 1, characterized in that: the first equivalent circuit is an equivalent circuit of a final device manufactured in the manufacturing process; in the simulating step, the second equivalent circuit is integrated into the first equivalent circuit describing the equivalent circuit of the final device; and in the simulating step, the electrical characteristics of the final device including the semiconductor element are simulated.

8. The electrical characteristic evaluation method according to claim 1, further comprising a step of presenting a user interface for specifying a component whose electrical characteristics are to be simulated in the simulating step, and in the simulating step, simulating the electrical characteristics of the component specified on the user interface.

9. An electrical characteristic evaluation apparatus for evaluating the electrical characteristics of a semiconductor device, comprising: an evaluation unit that evaluates the electrical characteristics of a semiconductor element formed in an intermediate step of a manufacturing process for manufacturing the semiconductor device; and a computer system that controls the evaluation unit, wherein the semiconductor device is configured to be represented by a first list that describes components that configure a first equivalent circuit including the semiconductor element, the computer system obtains a second list that describes components that configure a second equivalent circuit of the semiconductor element formed in the intermediate step, the computer system evaluates the electrical characteristics of the semiconductor element by the evaluation unit using the second equivalent circuit, and the computer system outputs the second list and an evaluation result of the electrical characteristics of the semiconductor element in a format that allows the second equivalent circuit described by the second list to be integrated into the first equivalent circuit described by the first list.

10. An electrical characteristic evaluation system for evaluating the electrical characteristics of a semiconductor device, comprising: the electrical characteristic evaluation apparatus of claim 9; and a simulation tool that simulates the electrical characteristics of the first equivalent circuit using the first list, wherein the simulation tool obtains the second list from the electrical characteristic evaluation apparatus and obtains evaluation results of the electrical characteristics of the semiconductor element from the electrical characteristic evaluation apparatus, the simulation tool integrates the second equivalent circuit described by the second list into the first equivalent circuit described by the first list, and the simulation tool simulates the electrical characteristics of the first equivalent circuit including the second equivalent circuit by performing the simulation using the electrical characteristics of the semiconductor element.

Images