JP5758212B2 - Element model, element model creation method, circuit verification method, and circuit verification apparatus - Google Patents

Description

  The present invention relates to an element model used for a simulation for verifying the operation of a circuit, an element model creation method for creating the element model, a circuit verification method using the element model, and a circuit verification apparatus.

  Generally, a circuit simulation is performed when designing a circuit of a semiconductor device and the circuit operation is verified. In the circuit simulation, an element model obtained by modeling an element incorporated in a circuit is used. FIG. 11 shows a conventional circuit simulation technique.

  A circuit verification means (hereinafter referred to as a simulator) 100 that executes circuit simulation receives a net list, element physical characteristic data, and simulation condition data. The net list is data indicating connection information of a circuit to be verified. The element physical characteristic data is data indicating the specific physical characteristic of the element used in the netlist. The simulation conditions include an input waveform input to the circuit at the time of simulation, power supply conditions, temperature, and the like.

  The simulator 100 uses the circuit analysis simulation function 102 to apply the input element physical characteristic data to the element model built in the simulator 100 and input a waveform corresponding to the simulation condition for the circuit represented by the netlist. A simulation is performed and a circuit operation verification result is output (see also Patent Document 1 below).

JP 2005-250874 A

  The conventional element model used in the simulator 100 only shows electrical characteristics according to the physical characteristics (resistance value, capacitance value, etc.) specific to general elements and the physical characteristics specific to the elements. It does not include a function for verifying a limit value of a current or voltage that causes a state (for example, disconnection or insulation film breakdown). Therefore, in order to verify the limiting characteristics, such as whether or not a current exceeding the limit value flows through the element during the simulation and whether or not a voltage exceeding the limit value is applied, as shown in FIG. The built-in element characteristic verification function 104 must be used. The verification target of the element characteristic verification function 104 built in the simulator 100 is limited, and there is a problem that the limit value of an element that is out of the verification target cannot be verified by the function.

  In addition, when the simulator 100 is different, the specifications of the element characteristic verification function 104 are different (the method for verifying the element voltage and the element current is different). If the specifications of the element characteristic verification function 104 are different for each simulator, the verifier may mistakenly specify a limit value or may easily cause a specification omission. More specifically, as described above, in the conventional method, the limit value data used in the element characteristic verification function 104 is not included in the element physical characteristic data, and the verifier as shown in FIG. It is necessary to create a file (device verification information for verification) describing limit value information separately from the device model used in the simulation, and input and operate the simulator 100. Therefore, if the specifications of the element characteristic verification function 104 are different for each simulator, a specification mistake is likely to occur. Also, by creating the element verification information separately from the element model, when there is a change in the physical characteristics of the element, the change is reflected only in the element model, and the element verification information may be missed.

  Some simulators 100 do not include the element characteristic verification function 104 itself. Such a simulator 100 has a problem that the limiting characteristics of the element cannot be verified.

  As described above, the conventional method has a problem that the restriction characteristic cannot be verified due to a lack of function by the simulator, or the function itself is not available and the verification itself cannot be performed.

  In the simulation, an element model that is not built in the simulator 100 may be created and used in the past, but even in this case, the conventional method uses the specific physical characteristics and the specific physical model. Only the element model in which the electrical characteristics corresponding to the characteristics are defined is created and used, and the above problem cannot be solved.

  The present invention has been proposed in order to solve the above-described problems, and an element model, an element model creation method, a circuit verification method, which can easily verify the limiting characteristics of an element without depending on circuit verification means, It is another object of the present invention to provide a circuit verification apparatus.

The element model creation method of the present invention is a creation method for creating an element model obtained by modeling the element used in a simulation for verifying the operation of a circuit composed of at least one element, A physical characteristic defining step in which a computer defines a specific physical characteristic of the element; and an electrical characteristic defining step in which an electrical characteristic using the specific physical characteristic of the element is defined and an electrical characteristic for performing the simulation is defined. And a limiting characteristic defining step for defining a layout limiting characteristic as a limiting characteristic indicating a limitation of an electrical characteristic according to a specific physical characteristic of the element, and according to a specific physical characteristic of the element during the simulation. A verification process definition step for defining a process content for verifying whether or not the electrical characteristic violates the restriction characteristic. In is configured.

The circuit verification method and the circuit verification apparatus according to the present invention are an element model obtained by modeling the element used in a simulation for verifying the operation of a circuit including at least one element, A physical characteristic defining unit that defines a specific physical characteristic, an electrical characteristic defining unit that defines an electrical characteristic that uses the specific physical characteristic of the element and performs the simulation, and a specific characteristic of the element A limiting characteristic defining unit that defines a limiting characteristic indicating a layout limitation of an electrical characteristic according to a physical characteristic of the device, and an electrical characteristic according to a specific physical characteristic of the element violates the limiting characteristic during the simulation. a limiting characteristic verification unit illustrating processes for verifying whether it is using the device model including, performs the simulation, the simulation sheet It is intended to verify the limiting characteristic in emissions.

  In addition, the circuit verification apparatus according to the present invention includes a creation unit that creates an element model by the creation method of the element model, the simulation using the element model created by the creation unit, and an element during the simulation. And circuit verification means for verifying the limiting characteristics.

  As described above, according to the present invention, there is an effect that the limiting characteristic of the element can be easily verified regardless of the circuit verification means.

It is a block diagram of the circuit verification system which concerns on embodiment. It is a figure which shows the structure of an element model. It is a figure which shows the structure of the element characteristic definition part which concerns on 1st Embodiment. It is a figure which shows the structure of the element characteristic verification part which concerns on 1st Embodiment. It is a figure which shows the specific description example of the element model which concerns on 1st Embodiment. It is a figure which shows the example of designation | designated of the element model in a net list. It is an example of the error message which shows that it became a disconnection state because the electric current value which flows into an element exceeded a limit value. It is a figure which shows the structure of the element characteristic definition part which concerns on 2nd Embodiment. It is a figure which shows the structure of the element characteristic verification part which concerns on 2nd Embodiment. It is a figure which shows the specific description example of the element model which concerns on 2nd Embodiment. It is a figure which shows the method of the conventional circuit simulation.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  [First Embodiment]

  As shown in FIG. 1, the circuit verification system 10 according to the present exemplary embodiment includes an element model creation unit 20 and a circuit verification unit 30. The circuit verification unit 30 executes a simulation for verifying the operation of the circuit configured by at least one element. The element model creation unit 20 is an element model obtained by modeling an element, and creates an element model used in the simulation.

  Each of the element model creation unit 20 and the circuit verification unit 30 includes a CPU (Central Processing Unit), a RAM (Random Access Memory), a ROM (Read Only Memory), an I / O (input / output) interface, and a communication interface. These are configured by a general computer configured to be connected to each other via a bus (not shown). Connected to the I / O interface are an HDD (hard disk drive), an operation unit such as a keyboard and a mouse, and a display unit such as a display. The communication interface is connected to a network such as a communication line or a LAN, and exchanges information with other terminals connected to the network.

  The circuit verification system 10 may be configured by a single computer having both the function of the element model creation device and the function of the circuit verification device. However, in this embodiment, the element model creation device and the circuit verification device are different. The circuit verification system 10 configured by a computer will be described as an example.

  The CPU of the computer constituting the element model creation unit 20 executes an element model creation program stored in the ROM, HDD, or the like of the computer. Note that the recording medium on which the program executed by the CPU of the element model creation unit 20 is stored is not limited to a ROM or HDD, but may be a CD-ROM drive or an FD drive, or a DVD disk or magneto-optical disk. Further, it may be a portable recording medium such as an IC card, a storage device such as an HDD provided outside the element model creation unit 20, and a database connected via a network, or other computer system, That database may be used.

  The CPU of the computer constituting the circuit verification unit 30 executes a program stored in the ROM, HDD or the like of the computer. The program executed by the CPU includes a program for executing a simulation for verifying the operation of the circuit. The recording medium that stores the program executed by the CPU of the circuit verification unit 30 is not limited to the ROM and the HDD, but may be a CD-ROM drive or an FD drive, a DVD disk, a magneto-optical disk, It may be a portable recording medium such as an IC card, a storage device such as an HDD provided outside the circuit verification unit 30, and a database connected via a network, or another computer system and its database. It may be.

  The element model creation unit 20 receives data indicating the specific physical characteristics of the elements constituting the circuit to be simulated via the operation unit, the communication interface, and the like. The data indicating the intrinsic physical characteristics of the element is, for example, data obtained from a result of actual measurement and analysis of the physical characteristics of the element by a manufacturer or the like (see also FIG. 3). For example, when the element is a resistance element, the resistance value of the element is referred to, and when the element is a capacitance element, the capacitance value of the element is referred to.

  In addition, the element model creation unit 20 receives data indicating restriction characteristics indicating restriction of electrical characteristics in accordance with the specific physical characteristics of the elements via the operation unit, the communication interface, and the like. Hereinafter, an electrical characteristic corresponding to a physical characteristic unique to the element is referred to as an electrical characteristic of the element, and a limiting characteristic indicating a limitation on the electrical characteristic is referred to as a limiting characteristic of the element.

  Here, the limiting characteristic of the element is, for example, the limit value of current or voltage that causes the element to become abnormal (becomes broken and breaks the insulation film, etc.), and the element is safe in terms of specifications. Operational range that is the range of voltage value and current value that can be operated, element layout restrictions (for example, a specific element must not be placed within a predetermined range from the element, or an element is placed in parallel with a specific element) Layout restrictions to prevent the electrical characteristics from being affected. The data indicating the limiting characteristics is also data obtained from the result of actual measurement and analysis of the physical characteristics of the element.

  The element model creation unit 20 defines the specific physical characteristics of the element based on the input data, defines the limiting characteristics of the element, and defines the electrical characteristics of the element that are to be simulated. Then, during the simulation, an element model is created by defining a processing content for verifying whether or not the electric characteristic of the element violates the limiting characteristic.

  More specifically, the definition of the specific physical characteristics of the element uses data indicating the input physical characteristics of the element, and the definition of the limit characteristics of the element uses data indicating the input limit characteristics of the element. To do. In addition, the electrical characteristics of the element are defined by applying data indicating the physical characteristics unique to the element to a template determined in advance according to the type of the element, and the processing content for verifying the limiting characteristics of the element is also determined in advance. The defined template is defined by applying the electrical characteristics of the element defined above.

  The element model can be created using Verilog-A description language used in many circuit simulators or CMI (Common Model Interface). Naturally, the circuit verification unit 30 as a circuit simulator according to the present embodiment supports the Verilog-A description language or CMI (Common Model Interface), and is configured to be able to interpret the description of the element model. It shall be. Hereinafter, the element model will be described in detail.

  FIG. 2 shows a configuration of the element model 40 created by the element model creation unit 20. The element model 40 of this embodiment includes an element characteristic definition unit 50 and an element characteristic verification unit 52.

  The element characteristic defining unit 50 is a part that defines element characteristics. FIG. 3 shows the configuration of the element characteristic defining unit 50. The element characteristic defining unit 50 according to the present embodiment includes a physical characteristic defining unit 60 that defines a specific physical characteristic of an element, and a limiting characteristic defining unit 62 that defines a limiting characteristic of the element.

  The element characteristic verification unit 52 is a description part necessary for verification of circuit and element characteristics, and is repeatedly performed by the circuit verification unit 30 at predetermined intervals along the operation time axis of the circuit to be verified during simulation. Is read. The predetermined interval is an interval determined by the simulator (circuit verification unit 30) or an interval designated by a simulation executor. FIG. 4 shows the configuration of the element characteristic verification unit 52. The element characteristic verification unit 52 includes an element characteristic simulation unit 70 and a limiting characteristic verification unit 72.

  The element characteristic simulation unit 70 is an electric characteristic of the element, and is a part that defines the electric characteristic for simulation. For example, when the element represented by the element model is a resistance element and the physical characteristic defined by the physical characteristic definition unit 60 is the resistance value of the element, the resistance value, voltage value, and current value of the element The device characteristics simulation unit 70 describes the electrical characteristics of the relationship expressed by Ohm's law.

  The limiting characteristic verifying unit 72 is a part indicating processing contents for verifying whether or not the electrical characteristics of the element violate the limiting characteristics of the element during the simulation of the circuit verifying unit 30. Note that the limited characteristic verification unit 72 may describe that the electrical characteristic is in a state of violating the limited characteristic so that the fact is output, or the electrical characteristic violates the limited characteristic. In such a case, a message indicating that the restriction characteristic is violated may be output when the message indicating that the restriction is violated is continued.

  The element model creation unit 20 inputs the created element model to the circuit verification unit 30.

  The circuit verification unit 30 receives the element model 40 created by the element model creation unit 20 and the net list and data indicating simulation conditions via the operation unit and the communication interface.

  The net list is data representing the connection state of the elements constituting the circuit to be verified. In the net list, an element model 40 of an element used for the circuit to be verified is specified, and the specified element model 40 is used in the simulation. The simulation conditions include data defining an input waveform input to the circuit during simulation, power supply voltage, environmental temperature, and the like.

  The circuit verification unit 30 applies the input element model to the circuit represented by the input netlist, performs a simulation according to the simulation conditions, and outputs a simulation result (circuit operation verification result). In addition, the circuit verification unit 30 also executes a verification process for limiting characteristics indicated by the element characteristic verification unit 52 of the element model 40 during the simulation. The circuit operation verification result obtained as a result of the simulation and the verification result of the limiting characteristic of the element (element verification result) may be output to and stored in a storage device such as an HDD or displayed on the display unit. Alternatively, it may be transmitted to another device via a communication interface.

  The verification of the limiting characteristics is realized by the circuit verification unit 30 executing the processing contents of the element characteristic verification unit 52 described in the element model during the normal simulation. As long as the verification unit 30 has only the circuit analysis simulation function 102 shown in FIG. 11, the verification of the limiting characteristics can be performed even if the element characteristic verification function 104 shown in FIG. 11 is not provided.

  FIG. 5 shows a specific example of the element model according to the present embodiment.

  This element model is an element model of a resistance element which is given the name “metal_resistor” and is connected to the p terminal and the n terminal. In the physical characteristic defining unit 60 of the element characteristic defining unit 50, a resistance value r of 1 ohm is defined as a specific physical characteristic of this resistive element, and in the limiting characteristic defining unit 62, as a limiting characteristic of this resistive element, A limit value current_limit of a current value of 1 mA is defined. The element model in FIG. 5 indicates that the element is broken and disconnected when a current having a current value exceeding 1 mA flows.

  Next, the element characteristic verification unit 52 will be described. In the element characteristic simulation unit 70 of the element characteristic verification unit 52, the value I (p, n) of the current flowing through the element connected between the p terminal and the n terminal is set to the voltage value V (p between the p terminal and the n terminal. , n) divided by the resistance value r of the element is shown as the electrical characteristics of the element. Further, the element characteristic simulation unit 70 also describes processing contents for setting the current value I (p, n) in a parameter called current.

  The limit characteristic verification unit 72 verifies (determines) whether or not the absolute value of current exceeds the limit value current_limit defined by the limit characteristic definition unit 62, and outputs an error message if it exceeds. The processing contents are shown.

  FIG. 6 shows an example of specifying an element model in the netlist. As shown in FIG. 6, it is specified that an element represented by an element model named metal_resistor is connected between the p terminal and the n terminal of the circuit Rtest to be simulated.

  The circuit verification unit 30 simulates the operation of the circuit represented by the input netlist using the element model specified as described above. Then, during the simulation, the limiting characteristics are verified by periodically executing the processing contents shown in the element characteristic verification unit 52 of FIG. In this way, the circuit verification unit 30 evaluates the resistance element metal_resistor by simulation, and when it is determined that a current exceeding the limit value of 1 mA flows through the element during the simulation, the circuit verification unit 30 determines that the wiring is disconnected, As shown in FIG. 7, an error message is output indicating that a disconnection state has occurred because the value of the current flowing through the element during simulation (2A in FIG. 7) exceeded the limit value. As a result of the element verification, the simulation of the circuit operation is continued even if the limit characteristic is violated.

  As described above, according to the present embodiment, since the element model created outside the circuit verification unit 30 is provided with the verification function of the limiting characteristic of the element, a verification environment independent of the circuit verification unit 30 is provided. It becomes possible to prevent the circuit design from causing a problem by incorporating the information on the limiting characteristics into the element model. In addition, when executing simulation, it is not necessary for a verifier of circuit operation to create a file for verifying limiting characteristics different from the element model used for simulation of circuit operation, and to perform element verification separately from the simulation. . Thereby, circuit design can be performed smoothly.

  In addition, according to the present embodiment, it is possible to perform verification by creating an element model obtained by modeling a specific element that is not represented by the element model built in the simulator.

  Note that in this embodiment, a resistance element is described as an example, but an element that can be represented by an element model is not limited to a resistance element. For example, even in various elements such as MOS transistors, bipolar transistors, diodes, capacitors, inductors, elements with special characteristics, etc., verify the limiting characteristics by including descriptions for element verification in the element model. Can do. For example, when creating an element model for a MOS transistor, limit values such as gate capacitance and drain capacitance are described in the element model as the limiting characteristics of the element, and the processing procedure for verification of the limiting characteristics is also described in the same manner as described above. You just have to.

  Further, in the present embodiment, an example has been described in which the description of the element characteristic verification unit 52 of the element model 40 is read and verified every time a predetermined time elapses along the time axis of the circuit operation. When verifying layout restrictions, it is not necessary to verify many times during the simulation. In this case, for example, the element verification is performed by acquiring a value indicating the layout state of the element only at the start of the simulation. Thus, the element characteristic verification unit 52 may be described to create an element model.

  Further, in the present embodiment, the element model creation unit 20 has been described as being realized by a CPU built in a computer executing a program stored in a ROM or the like, but is not limited thereto, for example, The verification executor operates an operation unit such as a keyboard or a mouse to create an element model in the same manner as described above by using data indicating the specific physical characteristics of the element and data indicating the limiting characteristics. You may make it implement | achieve the function of the model preparation part 20. FIG.

  [Second Embodiment]

  In the first embodiment, an example has been described in which, by adding a description for verifying the limiting characteristics to the element model, it is verified whether the electrical characteristics of the element violate the limiting characteristics during circuit simulation. However, in this embodiment, in addition to the element verification, the element model can verify the circuit operation in the case where an abnormal state (disconnection, etc.) occurs because the electric characteristic of the element violates the limiting characteristic. An example of creating is described.

  When a simulation is performed with a conventional device model, even if the device is in violation of the device's limiting characteristics during the simulation (for example, a state in which a large current exceeding the current limit value flows through the device), The simulation is continued with electrical characteristics corresponding to the physical characteristics.

  However, in reality, if the electrical characteristics of the element violate the limiting characteristics, the element will be in an abnormal state in which the physical characteristics inherent to the element cannot be exhibited (for example, disconnection or insulation film breakdown). The verification result indicates a circuit operation that is impossible in practice. Therefore, in the present embodiment, in the element model creation unit 20, not only the element verification described in the first embodiment but also an abnormal state where the element electrical characteristics violate the limiting characteristics. An element model from which a verification result of the circuit operation is obtained is used in the circuit verification unit 30.

  FIG. 8 shows the configuration of the element characteristic defining unit 50 of the element model according to the present embodiment. The element characteristic defining unit 50 according to the present embodiment includes a virtual physical characteristic defining unit 64 in addition to the physical characteristic defining unit 60 and the limiting characteristic defining unit 62 described in the first embodiment.

  The virtual physical characteristic defining unit 64 is a part that defines virtual physical characteristics for simulating an abnormal state of an element in a simulation. For example, when the limiting characteristic defining unit 62 of the element model of the resistive element defines a limiting characteristic with a current limit value of 1 mA, a virtual resistance for simulating a state where the current exceeds the limit value and is disconnected Define the value here.

  FIG. 9 shows a configuration of the element characteristic verification unit 52 according to the present embodiment. The element characteristic verification unit 52 according to the present embodiment also includes an element characteristic simulation unit 70, a limit characteristic verification unit 72, and a characteristic change unit 76. Since the element characteristic simulation unit 70 and the limiting characteristic verification unit 72 are the same as those in the first embodiment, the description thereof is omitted here.

  When it is determined that the electrical characteristics corresponding to the specific physical characteristics of the element are in violation of the limiting characteristics, the characteristic changing unit 76 converts the electrical characteristics used in the simulation into the physical characteristic defining unit 60. This is a part in which processing contents for changing from an electrical characteristic corresponding to the defined physical characteristic of the element to an electrical characteristic corresponding to the virtual physical characteristic defined by the virtual physical characteristic defining unit 64 are described. For example, the element model creation unit 20 creates the element model by defining the characteristic changing unit 76 using a creation rule predetermined for each type of element represented by the element model.

  As a result, the circuit verification unit 30 follows the description contents of the element characteristic verification unit 52 of the element model, while the electrical characteristic according to the specific physical characteristic of the element does not violate the limiting characteristic, and the physical characteristic definition unit 60 After the simulation is performed with the electrical characteristics according to the physical characteristics specific to the element defined in (1), and the electrical characteristics according to the specific physical characteristics of the element violate the limiting characteristics, the virtual physical characteristics definition unit 64 defines the characteristics. Simulation is performed with electrical characteristics corresponding to the virtual physical characteristics.

  FIG. 10 shows a specific description example of the element model according to the present embodiment.

This element model is an element model of a resistance element which is given the name “resistor” and which is connected to the p terminal and the n terminal. A resistance value R of 1 ohm is defined in the physical characteristic definition unit 60 of the element characteristic definition unit 50 as a specific physical characteristic of the resistance element, and 1A is defined in the limiting characteristic definition unit 62 as the limiting characteristic of the resistance element. The current value limit value current_limit is defined. The virtual physical property defining unit 64 defines a resistance value res_cutval of 1G (1 × 10 ⁹ ) ohms as a virtual physical property that simulates a disconnection.

  Next, description of the element characteristic verification unit 52 will be described. In this example, the element characteristic verification unit 52 is described in the order of the initial step (initial_step), the limiting characteristic verification unit 72, the characteristic change unit 76, and the element characteristic simulation unit 70.

  The initial step describes a process of dividing the limit value current_limit by the resistance value R to obtain the voltage value vol_limit and setting the resistance value R for the parameter Res. In this example, the limiting characteristic verifying unit 72 converts the current value defined by the limiting characteristic defining unit 62 into a voltage value in order to determine the limiting characteristic based on the voltage value instead of the current value. The initial step is executed only once when the simulation is started.

  Next, the limit characteristic verification unit 72 and the characteristic change unit 76 will be described. First, it is determined whether or not the voltage value V (p, n) between the p terminal and the n terminal exceeds the voltage value vol_limit (see also FIG. 10 (1)). The value of res_cut_val is set (see also (2) in FIG. 10), and an error message indicating that the wire is broken in violation of the limiting characteristics is output (see also (3) in FIG. 10), and the voltage value V (p, When it is determined that n) does not exceed the voltage value vol_limit, a processing procedure is described in which the value of the resistance value R is set in Res (see also FIG. 10 (4)). Here, FIG. 10B is a description corresponding to the characteristic changing unit 76, and the rest is a description corresponding to the limited characteristic verifying unit 72.

  That is, if the electrical characteristic according to the resistance value R does not violate the limiting characteristic of the element, the simulation is executed with the electrical characteristic according to the resistance value R, and the electrical characteristic according to the resistance value R is If the limit characteristic is violated, an error message indicating that the limit characteristic has been violated is output, and the electrical characteristic to be simulated is Res so that the electrical characteristic according to the resistance value res_cut_val at the time of abnormality The simulation is continued with the electrical characteristics corresponding to the resistance value res_cut_val. That is, when the abnormality occurs, the resistance value of the element is set high, and during the simulation, the value of the current flowing through the element is made smaller than when applying the above-described specific physical characteristics to simulate a disconnection state.

  In the element characteristic simulation unit 70, the value I (p, n) of the current flowing between the p terminal and the n terminal is shown, and the voltage value V (p, n) between the p terminal and the n terminal is divided by Res. Electrical characteristics are described. Note that, as described above, the value of Res is the normal state where the electrical characteristics of the element being simulated do not violate the limiting characteristics of the element, or the abnormal state where the electrical characteristics of the element violate the limiting characteristics of the element. It becomes a different value depending on.

  When the simulation is started, the circuit verification unit 30 reads the description of the element characteristic verification unit 52 of the element model and executes the process every time a predetermined time passes along the time axis of the circuit operation. This process is not executed except when the simulation is started.

  By creating the element model in this manner, not only the limiting characteristics of the elements are verified during the simulation by the circuit verification unit 30, but also the electrical characteristics of the elements violate the limiting characteristics during the simulation. However, it is also possible to verify the circuit operation that simulates the state in which an abnormality has occurred in the element.

DESCRIPTION OF SYMBOLS 10 Circuit verification system 20 Element model creation part 30 Circuit verification part 40 Element model 50 Element characteristic definition part 52 Element characteristic verification part 60 Physical characteristic definition part 62 Restriction characteristic definition part 64 Virtual physical characteristic definition part 70 Element characteristic simulation part (electrical (Characteristic definition part)
72 Restriction Character Verification Unit 76 Character Change Unit

Claims (9)

A creation method for creating an element model obtained by modeling the element used in a simulation for verifying an operation of a circuit including at least one element,
Computer
A physical property defining step for defining a specific physical property of the element;
An electrical characteristic defining step for defining electrical characteristics using the physical characteristics inherent to the element and performing the simulation;
A limiting characteristic defining step for defining a layout limiting characteristic as a limiting characteristic indicating a limitation of an electrical characteristic according to a specific physical characteristic of the element;
A verification process definition step for defining a process content for verifying whether or not an electrical characteristic corresponding to a specific physical characteristic of the element violates the restriction characteristic during the simulation;
A method for creating an element model for executing a process including: Computer
A virtual physical property defining step for defining a virtual physical property for simulating an abnormal state of the element in the simulation;
During the simulation, when it is verified that an electrical characteristic corresponding to the specific physical characteristic of the element violates the limiting characteristic, the electrical characteristic for performing the simulation is changed to a specific physical characteristic of the element. A change process defining step for defining a process content for changing from an electrical characteristic according to the electrical characteristic to the virtual physical characteristic;
The element model creation method according to claim 1, wherein a process further including: In the limiting characteristic defining step, a limit value of current or voltage at which no element disconnection occurs is defined as the limiting characteristic,
The element model creation method according to claim 2, wherein in the virtual physical characteristic defining step, virtual physical characteristics for simulating the disconnection of the element are defined. 4. The element model creation method according to claim 1, wherein the layout restriction characteristic is a layout restriction characteristic for preventing the electrical characteristic from being affected. 5. 5. The element model creation method according to claim 1, wherein, in the limiting characteristic defining step, a limit value of a gate capacitance or a drain capacitance of a MOS transistor is defined as the limiting characteristic. 3. The element model creation method according to claim 1, wherein, in the limiting characteristic defining step, the limiting characteristic is defined in the same file as the file defining the physical characteristics and the electrical characteristics. Computer
An element model obtained by modeling the element used in a simulation for verifying the operation of a circuit including at least one element,
A physical property definition section that defines the specific physical properties of the element;
An electrical characteristic defining unit that defines electrical characteristics using the physical characteristics inherent to the element and performing the simulation;
A limiting characteristic defining unit that defines limiting characteristics indicating a layout limitation of electrical characteristics according to the inherent physical characteristics of the element;
During the simulation, a limiting characteristic verification unit that indicates a processing content for verifying whether or not an electrical characteristic according to a specific physical characteristic of the element violates the limiting characteristic;
A circuit verification method for performing the simulation using an element model including: and verifying the limiting characteristics during the simulation. An element model obtained by modeling the element used in a simulation for verifying the operation of a circuit including at least one element,
A physical property definition section that defines the specific physical properties of the element;
An electrical characteristic defining unit that defines electrical characteristics using the physical characteristics inherent to the element and performing the simulation;
A limiting characteristic defining unit that defines limiting characteristics indicating a layout limitation of electrical characteristics according to the inherent physical characteristics of the element;
During the simulation, a limiting characteristic verification unit that indicates a processing content for verifying whether or not an electrical characteristic according to a specific physical characteristic of the element violates the limiting characteristic;
A circuit verification apparatus that stores an element model including the element model, performs the simulation using the stored element model, and verifies the limiting characteristics of the element during the simulation. Creating means for creating an element model by the creating method according to any one of claims 1 to 6;
Using the element model created by the creating means, performing the simulation, and circuit verification means for verifying the limiting characteristics of the element during the simulation,
A circuit verification apparatus comprising:

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