JP3091013B2 - LSI design database creation device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for preparing an LSI design database, and more particularly to an apparatus for preparing an LSI design database for preparing design data of individual parts used for designing an LSI as a database. .

[0002]

2. Description of the Related Art In the design of an LSI, there is a disadvantage that an expected logical operation cannot be obtained in practice, although the design should logically operate normally. This is because there are problems in circuit characteristics such as delay time, power consumption, synchronization timing, etc. of each circuit.
With the miniaturization of the I manufacturing process, there is a tendency to increase further in the future.

[0003] As a method of solving such inconvenience,
A method of performing a circuit simulation on a designed circuit has been adopted. That is, various information is extracted from a mask pattern of an actually designed logic circuit, and a simulation is performed based on the information to calculate an actual circuit characteristic value. The calculated circuit characteristic value is compared with a previously predicted characteristic value, and if the difference between the two is within a predetermined allowable range, it can be determined that the above-described inconvenience does not occur.

[0004]

However, the actual situation is that actual LSI design is performed within a very limited time, and the above-described simulation is performed for each circuit to calculate circuit characteristic values. It is virtually impossible to do so in view of the design period. In particular, in recent years, the demand for so-called ASICs (application-specific integrated circuits) has been increasing. In the design of the ASICs, a desired LSI is manufactured by using a large number of LSI design data prepared as individual components by a semiconductor manufacturer. The work of assembling will be performed.
In this case, it is almost impossible to design a desired LSI while performing the above-described simulation for each individual component within a short design period.
Also, even if a simulation is performed over time and circuit characteristic values are obtained, it cannot be left as a design asset in the past, so that a design asset that can be effectively used in later design cannot be constructed. There are also problems.

Accordingly, the present invention provides a method for designing an LSI,
LS that can easily obtain circuit characteristic values of various circuits
It is an object of the present invention to provide an apparatus for creating an I design database.

[0006]

Means for Solving the Problems (1) The first invention of the present application is an L for preparing design data of individual parts used for designing an LSI as a database.
In the SI design database creation device, circuit information extraction for extracting circuit connection information indicating a connection relationship of each element and circuit size information determined in relation to the size of each element from a mask pattern of each component. Apparatus, circuit parameter information for determining the electrical characteristics of each component of the element, circuit characteristic item information indicating circuit characteristic items to be prepared as a database, and calculation conditions for calculating the circuit characteristics An input device for inputting calculation condition information for designating a calculation method, calculation method information for designating a method for calculating circuit characteristics, and input logic waveform information for designating a pattern of an input logic waveform used for simulation. Based on the input information and the circuit connection information and circuit size information extracted from the circuit information extraction device, A circuit simulation input information creating device for creating circuit simulation input information necessary for the simulation, a circuit simulator device for performing a circuit simulation based on the circuit simulation input information, and outputting the result as circuit simulation output information, and a circuit simulation output Based on the information, a circuit characteristic value calculation device for obtaining a circuit characteristic value for each component, and based on given given data editing information,
Edit various circuit characteristic values for individual parts,
And a data editing device for creating a database as design data used for designing I.

(2) The second invention of the present application is the device according to the above-mentioned first invention, wherein the data editing device extracts desired data from the created database and converts the extracted data into given data editing information. The data is re-edited based on the data, and the re-edited data is stored again as a database, or a function of outputting the data to the outside is further provided.

[0008]

According to the LSI design database creating apparatus of the present invention, circuit connection information and circuit size information are automatically extracted from a mask pattern of a circuit used as an individual component for LSI design. . The circuit simulator automatically performs a circuit simulation based on these pieces of information and information for setting various parameters and conditions. The circuit characteristic value calculation device obtains various circuit characteristic values for individual components for various conditions based on the result of the simulation. The data editing device creates a database for these various circuit characteristic values. By using this database, the user can easily obtain desired circuit characteristic values for each component used when performing LSI design, and it is not necessary to perform simulation each time.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the illustrated embodiments. FIG. 1 is a block diagram showing a basic configuration of an apparatus for creating an LSI design database according to an embodiment of the present invention. This device has a function of creating a database of components for designing a so-called ASIC (application-specific integrated circuit). In ASIC design, a large number of components (partial integrated circuits) prepared in advance by a semiconductor manufacturer
LSIs with desired functions by combining
Will be designed. The semiconductor maker can use this apparatus to create a database M based on the mask pattern A of a circuit that is an individual part for the ASIC, and supply the database M to the user.

The main components of this device are, as shown in the block diagram of FIG.
The circuit simulation input information creation device 2, the circuit simulator 3, the circuit characteristic value calculation device 4, the data editing device 5, the display device 6, and the input device 7. The outline of the function of each of these components is as follows. The circuit information extracting device 1 includes, from a mask pattern A for each component, circuit connection information B indicating a connection relationship of each element,
Circuit size information C determined in relation to the size of each element;
Has the function of extracting On the other hand, from the input device 7, circuit parameter information D for determining the electrical characteristics of each component of the element, circuit characteristic item information E indicating circuit characteristic items to be prepared as a database, and circuit characteristic information Condition information F for designating calculation conditions when calculating
And calculation method information G for designating a method for calculating circuit characteristics
, Input logical waveform information H specifying a pattern of an input logical waveform used for simulation, and data editing information L used for creating a database M are input. The circuit simulation input information creating device 2 creates circuit simulation input information I necessary for circuit simulation based on the information B to H. The circuit simulator 3
A circuit simulation is performed based on the circuit simulation input information I, and the result is output as circuit simulation output information J. Circuit characteristic value calculation device 4
Calculates the circuit characteristic value K for each component based on the circuit simulation output information J thus output. The data editing device 5 edits the circuit characteristic value K thus obtained based on the data editing information L,
A database M is created as design data used to design the data.

Next, the operation of this device will be described in detail. First, a mask pattern A serving as a base of a database is prepared. That is, a mask pattern A is prepared for each circuit as an individual component for performing the ASIC design. Then, the mask pattern A is given to the circuit information extracting device 1. The circuit information extracting device 1 extracts circuit connection information B and circuit size information C based on the mask pattern A. Here, the circuit connection information B is information indicating the connection relationship of each element in the circuit, and the circuit size information C is information determined in relation to the size of each element. Since the mask pattern A is prepared as graphic data, the circuit information extracting device 1 extracts circuit connection information B and circuit size information C from the graphic pattern. For example, as shown in FIG. 2A, in order to extract circuit connection information B when two graphic patterns corresponding to a diffusion layer and a polysilicon layer are given, first,
An operation of recognizing the element is performed by a logical operation between the graphic patterns. That is, by recognizing a region where the logical product of both graphic operations is obtained as a gate and the diffusion layer regions on both sides thereof as a source and a drain, this can be recognized as a MOS transistor. By performing a phase operation on this, circuit connection information B as shown in FIG. 2B is obtained. Similarly, as shown in FIG. 3A, a figure pattern corresponding to the wiring layers α and β, a figure pattern corresponding to the wiring layer γ overlapping therewith, and a figure pattern corresponding to the contact are given. In this case, circuit connection information B as shown in FIG. 3B is obtained. On the other hand, the circuit size information C is information determined in relation to the size of each element, and is information such as the element size and the parasitic capacitance of the wiring. For example, when a figure pattern as shown in FIG. 4A is given, the size of these figures is extracted, and the parasitic capacitance _CXY of the wiring from the end point X to the end point Y is extracted. That is, as shown in FIG. 4B, the parasitic capacitance C _XY is equal to the capacitance C ₀ per unit area in the area S of the wiring layer.
Multiplied by The circuit connection information B as described above
And the method of extracting the circuit size information C is known,
A detailed description of a specific technique is omitted in this specification.

The circuit connection information B and the circuit size information C extracted by the circuit information extracting device 1 are given to the circuit simulation input information creating device 2.
At this time, the operator inputs each information D to H from the input device 7.
Input. In the device of the present embodiment, a keyboard is used as the input device 7, and the operator inputs these pieces of information from the keyboard. Hereinafter, each of these pieces of information will be described. First, the circuit parameter information D is information for determining the electrical characteristics of each component of the circuit. Specifically, the circuit parameter information D is a numerical value such as a thickness of an oxide film, an impurity concentration value in a diffusion layer, and the like. A process value for manufacturing an LSI is input as circuit parameter information D. The circuit characteristic item information E is information indicating an item of a circuit characteristic to be prepared as a database, for example, a delay time of the circuit (a time required from when an input signal is given to when an output signal is obtained). , Power consumption, and timing information (information related to the time that affects the operation timing of the synchronous logic circuit, such as the setup time, the hold time, and the minimum pulse width of the clock). Next calculation condition information F
Is information that specifies calculation conditions for calculating the above-described circuit characteristics, such as conditions such as temperature, the presence or absence of a load circuit, and the value of a load. The calculation method information G is information for designating a method for calculating circuit characteristics, and includes, for example, a method for measuring and calculating circuit characteristics, a measurement point (a boundary voltage between logical values “0” and “1”, and the like). Such information. The last input logical waveform information H is information for specifying a pattern of an input logical waveform to be used for a simulation. For example, the logical value “11001010” is used.
.. ".

As a result, the circuit simulation input information creating device 2 is provided with the circuit connection information B, the circuit size information C, and the above-mentioned information D to H necessary for performing the circuit simulation. The circuit simulation input information creating device 2 has a function of creating circuit simulation input information I to be given to the circuit simulator 3 based on the information. In the apparatus of this embodiment, SPICE (an electronic circuit simulator developed at the University of California, USA) is used as the circuit simulator 3. Therefore, the circuit simulation input information creating apparatus 2 uses the circuit simulation input information described in the SPICE format. Information is created. When various devices are used as the circuit simulator 3, the calculation condition information F may include information for specifying the simulator device to be actually used (for example, the name of the simulator device). . Then, the circuit simulation input information creating device 2 can create the circuit simulation input information I in a format suitable for the circuit simulator 3 to be used.

FIG. 5 shows a conceptual diagram of this circuit simulation. Generally, various circuit characteristics of a circuit to be measured differ depending on a load circuit connected to a subsequent stage. Therefore, in the device of the present embodiment, the circuit simulation input information creating device 2 creates the circuit simulation input information I in a state where the load circuit 11 is connected to the subsequent stage of the circuit 10 to be measured. The circuit simulation is nothing but an operation of simulating a computer to determine what output signal OUT is obtained by applying a predetermined input signal IN to the circuit 10 to which the load circuit 11 is connected. Here, the input signal IN is created by deforming the pattern of the input waveform specified by the input logical waveform information H at the blunt rate of the waveform specified by the calculation condition information F. The circuit simulation input information I includes circuit parameter information D, circuit characteristic item information E,
The circuit simulator 3 performs all necessary simulations based on the circuit simulation input information I, and outputs the result as circuit simulation output information J. For example, information indicating what input signal IN is applied and what output signal OUT is obtained is output as circuit simulation output information J.

The circuit characteristic value calculator 4 calculates a required circuit characteristic value K based on the circuit simulation output information J.
Is calculated. For example, as circuit characteristic item information E,
When the item “delay time” is set, the circuit characteristic value calculation device 4 calculates the delay time based on the circuit simulation output information J by referring to the calculation method information G, and calculates the circuit characteristic value. Output as K. More specifically, the delay time of the output signal OUT with respect to the input signal IN is output as the circuit characteristic value K. Similarly, when the item “power consumption” is set as the circuit characteristic item information E, the power consumption is calculated based on the current characteristics output as the circuit simulation output information J, and this is calculated as the circuit characteristic value. It will be output as K.

The data editing device 5 has various circuit characteristic values K calculated on various circuits under various conditions.
Will gather. For example, a mask pattern A for a circuit called “two-input NAND circuit” is prepared,
When the above-described simulation is performed based on the mask pattern A, various circuit characteristic values K are obtained. That is, the circuit characteristic value K obtained by setting the circuit characteristic item information E is “delay time” or “power consumption”, and the circuit parameter information D, the calculation condition information F, and the calculation method information G , Input logic waveform information H, the circuit characteristic value K differs. Such various circuit characteristic values K are obtained for a large number of circuits, respectively. Data editing device 5
Has a function of editing the circuit characteristic value K obtained in this way based on the data editing information L and creating a database M. What kind of policy should be edited may be determined in consideration of the convenience of the user of the database M. FIG. 6 shows a configuration example of the database M thus created. In this example, first, a large classification is made for each circuit. In other words, there are three major classifications: a 2-input NAND gate (corresponding to, for example, the mask pattern A1), a 2-input OR gate (corresponding to, for example, the mask pattern A2), and an inverter (corresponding to, for example, the mask pattern A3). I have. Subsequently, the input logic waveforms H1 and H2
The intermediate classification is made based on the difference from the above, and the small classification is made by the combination of the calculation condition F1 and the calculation method G1 and the combination of the calculation condition F2 and the calculation method G2. Further, a more detailed classification can be made based on a difference in circuit parameter information D such as a thickness of a gate oxide film of a MOS transistor constituting each logic element. The target database is constructed by the file storing the characteristic values K.

If a semiconductor maker establishes a database as described above, a user who performs ASIC design can use this database to perform a specific LSI design work. As described above, the ASIC design work is an operation of assembling using parts prepared by a semiconductor manufacturer in advance. For each part, various circuit characteristic values under various conditions are already stored in a database. Therefore, the user does not need to actually perform a time-consuming simulation for each component to be used, but only has to search for the desired circuit characteristic value from the database M. In short, if a semiconductor manufacturer once builds a database showing various circuit characteristic values under various conditions for individual components using the LSI design database creation device according to the present invention, this database becomes a design asset. Remains as
It can be used for ASIC design of many users.

In the apparatus of this embodiment, the data editing device 5 also has a function of reediting data in the database M. For example, if the database M prepared by the semiconductor manufacturer is not constructed in the format required by the user, or if the data is not edited in the unit required by the user, the user himself or herself inputs predetermined data editing information L from the input device 7. Is input, the data editing device 5 performs a process of extracting necessary data from the database M and re-editing the data based on the data editing information L. The re-edited data can be stored again as the database M, or can be output to an external device such as the display 6. Therefore, it is possible to reconstruct the database in a form suitable for the user's convenience, and it is possible to improve the user's LSI design work efficiency.

If the circuit characteristic value data required by the user does not exist in the database M prepared by the semiconductor manufacturer, the user himself inputs the conditions necessary for the simulation from the input device 7 to perform the simulation. , The required circuit characteristic values can be obtained as appropriate, and can be left as design resources in the database M.

As described above, the present invention has been described based on one embodiment shown in the drawings. However, the present invention is not limited to this embodiment, and can be implemented in various other modes.
For example, the five blocks 1 to 5 shown in FIG. 1 can be realized by a single computer,
It is also possible to realize as separate devices by a plurality of computers. Further, in the above-described embodiment, an example in which SPICE is used as the circuit simulator 3 has been described, but any other circuit simulator may be used.
Further, in the above-described embodiment, the database M is configured only with the circuit characteristic value K. However, actually, the database M includes not only the circuit characteristic value K but also a circuit diagram of a target circuit and its connection information. It is preferable to construct a database which is provided to the user as a comprehensive database for ASIC design.

[0021]

As described above, according to the apparatus for creating an LSI design database according to the present invention, circuit connection information and circuit size information are obtained from a mask pattern of a circuit used as an individual component for LSI design. Automatically extract and perform circuit simulation automatically based on these information and information for setting various parameters and conditions, and database of various circuit characteristic values obtained as a result as design assets Since it is left, it is possible to easily obtain a desired circuit characteristic value for each component used when performing LSI design, and it is not necessary to perform a simulation every time.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a basic configuration of an apparatus for creating an LSI design database according to an embodiment of the present invention.

FIG. 2 is a diagram illustrating an operation of extracting circuit connection information B in the device shown in FIG.

FIG. 3 is another diagram illustrating an operation of extracting circuit connection information B in the apparatus shown in FIG. 1;

FIG. 4 is a diagram illustrating an operation of extracting circuit size information C in the device shown in FIG. 1;

FIG. 5 is a conceptual diagram of a circuit simulation in the device shown in FIG.

FIG. 6 is a diagram showing an example of a database created by the device shown in FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Circuit information extraction device 2 ... Circuit simulation input information creation device 3 ... Circuit simulator 4 ... Circuit characteristic value calculation device 5 ... Data editing device 6 ... Display 7 ... Input device 10 ... Measurement target circuit 11 ... Load circuit A ... Mask pattern B ... Circuit connection information C ... Circuit size information D ... Circuit parameter information E ... Circuit characteristic item information F ... Calculation condition information G ... Calculation method information H ... Input logic waveform information I ... Circuit simulation input information J ... Circuit simulation output Information K: Circuit characteristic value L: Data editing information

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Yuji Machiya 1-1-1 Ichigaya-Kaga-cho, Shinjuku-ku, Tokyo Dai Nippon Printing Co., Ltd. (56) References JP-A-3-100868 (JP, A) Kaihei 2-266474 (JP, A) (58) Field surveyed (Int. Cl. ⁷ , DB name) H01L 21/82 H01L 27/118

Claims (2)

(57) [Claims] An apparatus for creating an LSI design database for preparing design data on individual components used for designing an LSI as a database, comprising: a mask pattern for each component; A circuit information extraction device for extracting circuit connection information indicating a connection relationship and circuit size information determined in relation to the size of each element; circuit parameter information for determining electrical characteristics of each element of the element; and a database. Circuit characteristic item information indicating an item of a circuit characteristic to be prepared as: a calculation condition information for specifying a calculation condition for calculating the circuit characteristic; and a calculation method for specifying a method for calculating the circuit characteristic. An input device for inputting information and input logical waveform information specifying a pattern of an input logical waveform used for simulation; A circuit simulation input information creation device that creates circuit simulation input information necessary for circuit simulation based on each information input from the input device, and circuit connection information and circuit size information extracted from the circuit information extraction device; A circuit simulator that performs a circuit simulation based on the circuit simulation input information and outputs the result as circuit simulation output information; and a circuit characteristic that obtains a circuit characteristic value for the individual component based on the circuit simulation output information. A value computing device, a data editing device that edits various circuit characteristic values of the individual components based on given given data editing information, and creates a database as design data used for designing an LSI. And An apparatus for creating an LSI design database. 2. The apparatus according to claim 1, wherein the data editing apparatus extracts desired data from the created database, re-edits the data based on given predetermined data editing information, and re-edits the data. An apparatus for creating a database for LSI design, further having a function of storing the output data again as a database or outputting the data to the outside.