JP2004062346A - Apparatus and method for automatically determining device size - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a device size automatic determination apparatus in which design manhour for determining a device size on the basis of device information is shortened. <P>SOLUTION: When a required resistance value and a resistance specification 101 concerning restriction on a layout are inputted through a specification input part 102, a size examination part 112 sets the initial value of the size from the restriction on the layout, extracts a resistance value in the size initial value from a resistance size dependency database 109 in which size dependence data of the resistance value are stored, determines whether the extracted resistance value satisfies the inputted resistance specification or not, and when the resistance value does not satisfy the resistance specification, it repeats the correction of the size in accordance with a set size correction rule to automatically calculate and output the device size. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a technology for automatically determining a size of a device constituting a semiconductor integrated circuit, particularly a diode element, a resistance element, and a capacitance element that satisfy design specifications, and reducing design man-hours and design errors.
[0002]
[Prior art]
Conventionally, when determining the optimum size of a device constituting a semiconductor integrated circuit, a method of determining a device size based on a characteristic value to be realized and a characteristic value per unit size of the device has been adopted.
[0003]
For example, in an analog circuit design, a method may be employed in which characteristic values of an element such as a current value, a resistance value, and a capacitance value of the element are determined in advance, and an element size that satisfies the characteristic conditions is determined later. . At this time, although the approximation is very rough, in the case of a diode element, the size is determined based on the current value to be realized and the current value (constant value) per unit area of the PN junction surface. Here, in a broad sense, a device in which the base and the collector of a bipolar transistor having a junction structure of PNP or NPN are connected to a common terminal, and the PN junction of the base and the emitter is used for the same purpose as a diode. Defined as a diode element.
[0004]
In the case of a resistance element, the size is determined based on a resistance value to be realized and a sheet resistance value (constant value). In the case of a capacitance element, the size is determined based on the capacitance value to be realized and the capacitance value (constant value) per unit area.
[0005]
Since such a first-order approximate device size determination method is very simple, there is software for automatically creating a mask layout of a semiconductor circuit having this function.
[0006]
FIG. 34 shows a configuration example of a processing unit and a processing flow when a resistance of 1000Ω is designed by such mask layout automatic creation software.
[0007]
In FIG. 34, a resistance value examination unit 301 examines a resistance value to be realized in terms of circuit characteristics, and outputs a design device specification 302 of a resistance of 1000 ohms. Also, requests for minimizing the shape and area of the element are output as specifications.
[0008]
This specification is input to the specification input unit 303. At this time, if there is a restriction on the space where the resistance element can be installed, the shape of the resistor can also be input as a specification according to the installation space of the resistance value. As a shape that can be specified for the element, there is a shape such as a linear type or a bent type as shown in FIG. Also, in the case of a shape such as a bending die, it has a function of selecting the number of times of bending and a line interval like the bending die (1), the bending die (2), and the bending die (3).
[0009]
Next, the number-of-sheets examining unit 304 calculates the number of sheets of the resistor realizing the specification. At this time, the data of the sheet resistance value of the resistance element stored in the first device information unit 305 is used. In this example, it is assumed that data that the sheet resistance value becomes 100Ω is stored. As a result of this study, it is concluded that the sheet number specification 306 should be designed with a size such that the number of sheets becomes ten.
[0010]
There are countless combinations of the resistance line width W and the resistance line length L of the resistors that make the number of sheets 10 such as (W, L) = (2 μm, 20 μm), (1 μm, 10 μm), (0.5 μm, 5 μm). I do. Therefore, next, in the size examination unit 307, a size to be specifically adopted is examined based on a requested specification such as a desire to minimize the area. At this time, data such as a resistance line width W ≧ 0.5 μm in the design rules stored in the design rule unit 308 is required. As a result of this study, it is concluded that the size output 309 should be designed with (W, L) = (0.5 μm, 5 μm).
[0011]
The conventional automatic size determination processing 310 surrounded by a dotted line in FIG. 34 is a part related to the processing of the conventional mask layout automatic creation software.
[0012]
[Problems to be solved by the invention]
However, in the conventional method, a device size is determined by treating characteristic values per unit size of a device, such as a current value per unit area, a sheet resistance value, and a capacitance value per unit area, as constant values. On the other hand, in an actual device, these values are not necessarily constant values, and the conventional method is insufficient for performing a more accurate design.
[0013]
Therefore, it is necessary to determine the size with high accuracy corresponding to the fact that the current value, the sheet resistance value, and the capacitance value per unit area are variable values having size dependence.
[0014]
For example, in the case of a resistive element, as the device size becomes smaller, the effects of parasitic effects and shape effects in which the device is actually manufactured cannot be ignored. Therefore, the relationship of the following formula (1), which is a conventional calculation method, does not hold.
[0015]
Resistance value = sheet resistance value (fixed value) x number of sheets ... (1)
Therefore, as one method for accurately estimating, there is a method of the following equation (2) using an effective sheet resistance value in which the sheet resistance value has size dependency.
[0016]
Resistance value = Effective sheet resistance value (variable value) x number of sheets ... (2)
In this method, a parasitic effect and an influence of a shape effect are included in the effective sheet resistance value (variable value).
[0017]
As another method, there is a method of the following equation (3) in which the effective sheet number in which the shape effect is reflected in the sheet number and the parasitic resistance is further corrected.
[0018]
Resistance value = sheet resistance value (fixed value) x number of effective sheets + parasitic resistance ... (3)
In this method, the sheet resistance value (fixed value) represents a value at a size such that the effects of parasitic effects and shape effects can be ignored. The effective number of sheets reflects the actual dimensions, and the parasitic resistance estimates and uses the actual value itself.
[0019]
In determining the size of the resistance element, in order to further increase the accuracy of the value obtained as the size output 309 in FIG. 34, an additional consideration processing unit 314 as shown in FIG. 36 is necessary. This is in the form of equation (2) above.
[0020]
In the additional data examination unit 311, examination is performed based on data on the size dependence of the effective number of sheets stored in the second device information unit 312. As an example, it is assumed that data that the effective sheet resistance value is 110Ω when W = 0.5 μm is stored. As a result of this study, it is concluded that the modified size output 313 should be designed with (W, L) = (0.5 μm, 4.54 μm).
[0021]
The conventional additional examination process 314 surrounded by a dotted line in FIG. 36 is an indispensable part for highly accurate device sizing, but it is necessary to manually execute this for each device individually. Therefore, many design man-hours are required.
[0022]
There are many other items that require additional investigation in determining the device size with high accuracy, and there are many issues. The following summarizes these issues.
[0023]
The first problem is that it is necessary to consider the size dependence of device characteristics. However, in the conventional example, many design man-hours were required in order to accurately judge and design each device.
[0024]
The second problem is that the device characteristics often change depending on the voltage condition and the current condition, and it is necessary to consider the voltage dependency and the current dependency. However, in the conventional example, many design man-hours were required in order to accurately judge and design each device.
[0025]
A third problem is that device characteristics often change depending on temperature conditions during operation, and it is necessary to consider temperature dependence. However, in the conventional example, many design man-hours were required in order to accurately judge and design each device.
[0026]
The fourth problem is that a semiconductor device designed with the same size has characteristic variations due to process variations at the time of manufacturing, and the amount of the variation depends on the size of the device. Is necessary. Since the characteristic variation has a great effect on the circuit operation, it is very important to consider how much the characteristic variation is allowed in circuit design. FIG. 37 shows an example of the relationship between the center characteristic and the characteristic variation of the resistance value of the resistance element. The horizontal axis is the resistance line length L, and the vertical axis is the resistance value R. This example shows that the smaller the resistance line length L, the larger the characteristic variation width. In the conventional example, many design man-hours are required to accurately determine and design a device size that satisfies a process variation value allowable in design specifications.
[0027]
A fifth problem is that when designing an analog circuit or the like, there is a characteristic difference (hereinafter referred to as a characteristic mismatch) between devices of the same size that are arranged close to each other in the expectation that the characteristics will be the same, and the amount of mismatch Since there is a device size dependency, it is necessary to consider this characteristic mismatch at the time of design. The characteristic mismatch is a kind of the characteristic variation described in the fourth problem. However, while the characteristic variation targets an element of the same size everywhere, the characteristic mismatch is arranged close to minimize the variation. Target devices. Since the characteristic mismatch has a significant effect on the circuit characteristics even if the difference is small, only the devices that want to have the same characteristics as much as possible, so how much characteristic mismatch can be tolerated in circuit design? It is very important to consider. FIG. 38 shows an example of the relationship between the center characteristic of the resistance value, the characteristic variation, and the characteristic mismatch. The characteristic mismatch width is smaller than the characteristic variation width. As the resistance line length L decreases, the characteristic mismatch width increases. In the conventional example, many design man-hours were required in order to accurately determine and design a device size that satisfies the value of the characteristic mismatch allowable in the design specification.
[0028]
A sixth problem is that when simulating device characteristics using a circuit simulator, there is a simulation error, and the simulation error depends on the size of the device. That is. In order to simulate semiconductor device characteristics, modeling of device characteristics is performed. The simulation error is a difference between the actual measurement value and the simulation value of the device characteristic, and depends on the shape of the adopted model formula and the extraction accuracy of the model parameters. It is very important to consider how much simulation error is allowed in circuit design. In the conventional example, many design man-hours were required in order to accurately determine and design a device size that satisfies a simulation error allowable in design specifications.
[0029]
A seventh problem is that all or a plurality of the first to sixth problems must be satisfied at the same time. FIG. 39 shows an example of the execution flow. After the first-stage examination 315, the second-stage examination 316, and the third-stage examination 317, and after the final-stage examination 318 is completed, examination and size correction are performed in order for necessary issues, and the final size output 319 is finally output. Results are obtained. Thus, many design man-hours were required to process each study in order. In addition, by repeating the correction, it is possible that the items that have already been examined may not be satisfied. Therefore, it was necessary to repeat the processing repeatedly and many times, which required much more design man-hours, and was very inefficient.
[0030]
An eighth problem is that when selecting an optimum material from a plurality of device sizes corresponding to different materials, it is necessary to make a determination in consideration of the first to seventh problems. When a semiconductor element is manufactured, not only the size and layout shape but also the constituent material itself may be changed. In the case of a manufacturing process for a MOS transistor, there is an example in which a resistor has a portion having the same impurity distribution as a source or a drain, or uses polysilicon as a resistor. There is an example in which a capacitor is formed using a gate oxide film portion or two layers of polysilicon. Devices having different materials have different characteristics. In the conventional example, many design man-hours were required in order to accurately judge and design.
[0031]
The ninth problem is that the amount of device information used for examining the first to eighth problems is enormous. If device information is stored in the form of numerical data in a table map system, the amount of information becomes enormous. If the device information is stored as a graph, it is not suitable for automation.
[0032]
As described above, in order to determine a device size with high accuracy, it is necessary to consider a lot of device information. Here, in addition to the size dependence, voltage dependence, current dependence, and temperature dependence of the device characteristics, the size dependence of the characteristic variation, the size dependence of the characteristic mismatch, and the size dependence of the simulation error in a broad sense. Device information or device characteristics.
[0033]
In the conventional example, there is a problem that an extremely large number of design man-hours are required in order to consider a large amount of device information.
[0034]
Moreover, since the operation is complicated, there is a possibility that a design error may occur. There are cases where the designer mistakes the data or overlooks the data other than the data of interest. As a result, a design failure may occur. For example, it is conceivable that as a result of deciding the size only by paying attention to minimizing the area, overlooking the data that the characteristic variation of the decided size is very large, a design failure occurs.
[0035]
SUMMARY OF THE INVENTION It is an object of the present invention to reduce the number of design steps when designing a device based on device information and reduce design defects in circuit design, and to reduce the amount of data in a device characteristic database. It is an object of the present invention to provide a determination device and a method.
[0036]
[Means for Solving the Problems]
In order to achieve the above object, nine outlines of the present invention that solve the nine problems are listed below.
(1) Automating highly accurate device size determination in consideration of the fact that semiconductor device characteristics have size dependence.
(2) Automating highly accurate device sizing in consideration of the fact that the characteristics of a semiconductor device have voltage dependency or current dependency.
(3) Automating highly accurate device size determination in consideration of the fact that the characteristics of a semiconductor device have temperature dependence.
(4) Automating highly accurate device size determination in consideration of the fact that the characteristics of a semiconductor device have characteristic variations and the amount of the characteristic variation has size dependence.
(5) Automating device size determination with high accuracy in consideration of the fact that the characteristics of a semiconductor device have a characteristic mismatch and that the amount of the characteristic mismatch has size dependence.
(6) A device simulation model used for circuit simulation of the characteristics of a semiconductor device has a simulation error, and a highly accurate device size determination taking into account that the simulation error has size dependency is automated.
(7) A plurality of items described in (1) to (6) are automatically and simultaneously and efficiently executed.
(8) When there are a plurality of options for the material of the semiconductor device, the sizes of the respective materials are automatically determined, and the results are automatically compared to determine the optimum material and to determine the device size with high accuracy. Automate.
(9) As a method of storing data in the semiconductor device characteristic database used in the items described in (1) to (8) above, a model formula that approximates device characteristics is used.
[0037]
Specifically, it is configured by the following solution.
[0038]
A first configuration of the present invention is characterized by comprising a first specification input unit, a first device characteristic database, and a first size examination unit.
[0039]
The first specification input unit inputs design specifications relating to desired device characteristic values and layout restrictions of devices constituting the semiconductor integrated circuit. Various device characteristics such as a resistance value for a resistance element, a capacitance value for a capacitance element, and a current value under a predetermined voltage condition or a voltage value at a predetermined current value for a diode element are included in the device characteristic value. Is included. The restrictions on the layout include a restriction on a layout place and a request to minimize an area. When designating the restrictions on the layout location, the size range of the device's vertical length and horizontal length is specified.
[0040]
The first device characteristic database stores size dependence data of device characteristic values under a predetermined temperature condition, a predetermined voltage condition, or a current condition.
[0041]
The first size consideration unit first sets an initial value of the device size, extracts a device characteristic value at the initial size value from the first device characteristic database, and determines whether the extracted device characteristic value satisfies the input design specification. It is determined whether or not the device size does not satisfy the design specification. By repeatedly performing the size correction according to the set size correction rule, the device size is automatically calculated and output.
[0042]
According to the first configuration, the device size can be automatically determined in response to the device characteristic value having a size dependency.
[0043]
Next, a second configuration of the present invention is characterized by comprising a second specification input unit, a second device characteristic database, and a second size examination unit.
[0044]
The second specification input unit includes an arbitrary voltage condition in a predetermined voltage range or an arbitrary current condition in a predetermined current range of a device configuring the semiconductor integrated circuit, a device characteristic value desired under the condition, And design specifications relating to layout constraints. Here, the voltage condition or the current condition refers to a condition in which a desired device characteristic value is desired to be obtained in a state where a voltage is applied to the device or a state in which a current is flowing to the device. Or mean. Depending on the device, the condition of the applied voltage or the flowing current is not one type but may be two or more types. In the case where there are a plurality, a combination of voltage conditions and current conditions is specified.
[0045]
The second device characteristic database stores size-dependent data and voltage-dependent data, or size-dependent data and current-dependent data of device characteristic values under predetermined temperature conditions.
[0046]
The second size consideration unit first sets an initial value of the device size, extracts a device characteristic value of the initial value size under the specified voltage condition or current condition from the device characteristic database, and receives the extracted device characteristic value. It is determined whether or not the design specification is satisfied. If the design specification is not satisfied, the device size is automatically calculated and output by repeating the size correction according to the set size correction rule.
[0047]
As described above, in the first configuration, the voltage or current condition is only one predetermined condition, whereas in the second configuration, the voltage or current condition is arbitrary in a predetermined voltage range or in a predetermined current range. The device size is automatically determined by designating an arbitrary current condition.
[0048]
According to the second configuration, the device size can be automatically determined in response to the voltage dependence or the current dependence of the device characteristic value.
[0049]
Next, a third configuration of the present invention is characterized by comprising a third specification input unit, a third device characteristic database, and a third size examination unit.
[0050]
An arbitrary temperature condition in a predetermined temperature range, a desired device characteristic value under the temperature condition, and design specifications relating to layout restrictions are input to the third specification input unit. Here, the temperature condition means under what temperature condition the device wants to obtain a desired device characteristic value.
[0051]
The third device characteristic database stores size dependence data and temperature dependence data of device characteristic values under a predetermined voltage condition or a predetermined current condition.
[0052]
The third size examination unit first sets an initial value of the device size, extracts a device characteristic value of the initial value size under the designated temperature condition from the device characteristic database, and extracts a design specification to which the extracted device characteristic value is input. It is determined whether or not the size is satisfied. If the design specification is not satisfied, the device size is automatically calculated and output by repeating the size correction according to the set size correction rule.
[0053]
As described above, in the first configuration, the temperature condition is only one predetermined condition, whereas in the third configuration, an arbitrary temperature condition in a predetermined temperature range is designated and the device size is automatically set. It is determined.
[0054]
According to the third configuration, the device size can be automatically determined in response to the temperature dependence of the device characteristic value.
[0055]
Next, a fourth configuration of the present invention comprises a fourth specification input unit, the first device characteristic database, a fourth device characteristic database, and a fourth size examination unit. I do.
[0056]
The fourth specification input unit inputs design specifications relating to a desired device characteristic value of the device constituting the semiconductor integrated circuit, an allowable variation amount condition of the device characteristic value, and a layout constraint. Here, the allowable variation amount condition is a condition to what extent the variation amount of the device characteristic value can be tolerated. The allowable variation amount conditions include, for example, the allowable variation amount of a current value under a predetermined voltage condition for a diode element, the allowable variation amount of a voltage value under a predetermined current condition, and the resistance value of a resistance element. In the case of a capacitive element, the allowable variation of the capacitance value and the like are included. As the index, an index suitable for expressing the variation of the device characteristic value is selected by using the ratio of the allowable variation amount (within what percentage) or the absolute amount itself.
[0057]
The fourth device characteristic database stores size dependence data of the variation amount of the device characteristic value under a predetermined temperature condition, a predetermined voltage condition, or a current condition.
[0058]
The fourth size examination unit determines a designable size based on the input allowable variation amount condition and the size dependence data of the variation amount of the device characteristic value stored in the fourth device characteristic database. An area is set, an initial value of a device size is first set from an area of a designable size, a device characteristic value in the initial value size is extracted from the first device characteristic database, and the extracted device characteristic value is input. Judge whether the design specifications are satisfied or not. If the design specifications are not satisfied, the device size is automatically calculated and output by repeating the size correction from the area of the designable size according to the set size correction rule. .
[0059]
As described above, in the fourth configuration, the device size is automatically determined by additionally specifying the allowable variation amount condition of the device characteristic value that is not included in the first configuration.
[0060]
According to the fourth configuration, it is possible to automatically determine the device size in response to the condition of the allowable variation amount of the device characteristic value.
[0061]
Next, a fifth configuration of the present invention includes a fifth specification input unit, the first device characteristic database, a fifth device characteristic database, and a fifth size examination unit. I do.
[0062]
The fifth specification input section receives design specifications relating to a desired device characteristic value, an allowable mismatch amount condition of the device characteristic value, and a layout constraint of a device constituting the semiconductor integrated circuit. Here, the allowable mismatch amount condition of the device characteristic value is a kind of characteristic variation. In particular, to what extent the characteristic difference between two adjacent devices of the same size, which are expected to have the same characteristics, is allowable. It is a condition that can be done. Although this is a special case, it is an important index in terms of circuit characteristics, so it is necessary to define it separately from characteristic variations that assume all cases. The allowable mismatch amount condition includes, for example, an allowable mismatch amount of a current value under a predetermined voltage condition for a diode element, an allowable mismatch amount of a voltage value under a predetermined current condition, and a resistance value if a resistive element. This includes the allowable mismatch amount of the value and the allowable mismatch amount of the capacitance value in the case of a capacitive element. As the index, an index suitable for expressing the mismatch amount of the device characteristic value by using the ratio of the amount of mismatch (within what percentage) or the absolute amount itself is selected.
[0063]
The fifth device characteristic database stores size dependency data of the mismatch amount of the device characteristic value under a predetermined temperature condition, a predetermined voltage condition, or a current condition.
[0064]
The fifth size examining unit determines a designable size based on the input allowable mismatch amount condition and the size dependence data of the mismatch amount of the device characteristic value stored in the fifth device characteristic database. An area is set, an initial value of a device size is first set from an area of a designable size, a device characteristic value in the initial value size is extracted from the first device characteristic database, and the extracted device characteristic value is input. Judge whether the design specifications are satisfied or not. If the design specifications are not satisfied, the device size is automatically calculated and output by repeating the size correction from the area of the designable size according to the set size correction rule. .
[0065]
As described above, in the fifth configuration, the device size is automatically determined by additionally specifying the allowable mismatch amount condition of the device characteristic value that is not included in the first configuration.
[0066]
According to the fifth configuration, the device size can be automatically determined in response to the presence of the allowable mismatch amount condition of the device characteristic value.
[0067]
Next, a sixth configuration of the present invention includes a sixth specification input unit, the first device characteristic database, a sixth device characteristic database, and a sixth size study unit. I do.
[0068]
The sixth specification input unit inputs design specifications relating to a desired device characteristic value, an allowable simulation error condition of the device characteristic value, and a layout constraint of a device constituting the semiconductor integrated circuit. Here, the permissible simulation error condition is a condition to which degree an error when a device characteristic is simulated by a circuit simulator is permissible. The error depends on the simulation model equation of each device and the extraction error of the model parameters. The allowable simulation error condition is specified by a ratio (within what percentage) or an absolute amount.
[0069]
The sixth device characteristic database stores size dependence data of a simulation error of a device characteristic value under a predetermined temperature condition, a predetermined voltage condition, or a current condition.
[0070]
The sixth size examining unit determines a designable size based on the input allowable simulation error condition and the size dependence data of the simulation error of the device characteristic value stored in the sixth device characteristic database. An area is set, an initial value of a device size is first set from an area of a designable size, a device characteristic value in the initial value size is extracted from the first device characteristic database, and the extracted device characteristic value is input. Judge whether the design specifications are satisfied or not. If the design specifications are not satisfied, the device size is automatically calculated and output by repeating the size correction from the area of the designable size according to the set size correction rule. .
[0071]
As described above, in the sixth configuration, the device size is automatically determined by additionally designating an allowable simulation error condition not included in the first configuration.
[0072]
According to the sixth configuration, the device size can be automatically determined in response to the existence of the allowable simulation error condition.
[0073]
Next, a seventh configuration of the present invention is characterized by comprising a seventh specification input unit, a seventh device characteristic database, and a seventh size examination unit.
[0074]
The seventh specification input unit includes an arbitrary voltage condition in a predetermined voltage range or an arbitrary current condition in a predetermined current range, an arbitrary temperature condition in a predetermined temperature range, and a device characteristic of a device constituting the semiconductor integrated circuit. At least one selected from the permissible variation amount condition of the value, the permissible mismatch amount condition of the device characteristic value, and the permissible simulation error condition of the device characteristic value, a desired device characteristic value, and design specifications relating to layout constraints Is entered.
[0075]
The seventh device characteristic database includes an arbitrary voltage condition in a predetermined voltage range or an arbitrary current condition in a predetermined current range, an arbitrary temperature condition in a predetermined temperature range, an allowable variation amount condition, an allowable mismatch amount condition, and Voltage-dependent data or current-dependent data of a device characteristic value under a predetermined temperature condition, temperature of a device characteristic value under a predetermined voltage condition or a predetermined current condition corresponding to a condition selected from the allowable simulation error conditions, respectively. Stores dependence data, size dependence data of the variation amount, size dependence data of the mismatch amount, and size dependence data of the simulation error of the device characteristic value under the predetermined temperature condition, the predetermined voltage condition or the predetermined current condition. Specified temperature conditions and specified Size dependence data of the device characteristic values are stored in the voltage condition or a predetermined current condition.
[0076]
When at least one condition selected from the permissible variation amount condition, the permissible mismatch amount condition, and the permissible simulation error condition is input, the seventh size studying unit determines the input condition and the seventh device Based on the device characteristic value stored in the characteristic database and the corresponding variation amount, mismatch amount, and size dependence data of the simulation error, a designable size area is set, and the designable size First, an initial value of the device size is set from within the area, the device characteristic value at the initial value size is extracted from the seventh device characteristic database, and it is determined whether or not the extracted device characteristic value satisfies the input design specification. If it does not meet the design specifications, it must be within the designable size area according to the set size correction rules. By repeating the modification Luo size, and outputs the device size is automatically calculated.
[0077]
According to the seventh configuration, batch processing is efficiently performed in response to a plurality of conditions included in each of the first to sixth configurations, and a device size that satisfies various design specification conditions is automatically determined. Can be.
[0078]
Next, in the eighth configuration of the present invention, the first to seventh device characteristic databases store data corresponding to the respective materials of the same type of device made of a plurality of different materials, and 7 is characterized in that the size study unit 7 determines a plurality of device sizes corresponding to different materials, compares the plurality of device sizes with each other, and determines an optimum material satisfying the design specification based on a predetermined criterion. I do.
[0079]
According to the eighth configuration, when a material can be selected for a device of the same type, an optimal material and an optimal size of a device satisfying design specification conditions can be automatically determined.
[0080]
Further, in the ninth configuration of the present invention, the device characteristic database included in the first to eighth configurations includes a model expression relating to the size dependence, voltage or current dependence, and temperature dependence of the device characteristic value. The data is stored.
[0081]
According to the ninth configuration, the data to be stored in the device characteristic database is not in a table map format but in a model formula format, thereby reducing the amount of data to be stored and simultaneously executing a plurality of study items. It is easier to do.
[0082]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.
[0083]
(1st Embodiment)
FIG. 1 shows a device size automatic determination processing unit for realizing a resistance element having a resistance value according to a specified specification according to a first embodiment of the present invention in response to the fact that the resistance element has size dependence. FIG. 3 is a model diagram showing a configuration and a processing flow of a processing unit 113.
[0084]
In FIG. 1, a design specification 101 is a specification of a resistance element to be designed. There are the following two types of specifications in the present embodiment.
[0085]
-Desired resistance value
・ Restrictions on layout
There are the following two types of layout restrictions.
[0086]
・ Minimize area
.Maximum and minimum conditions for the line width W and line length L of the resistive element
The device size automatic determination processing unit 113 includes a specification input unit 102 (first specification input unit) to which the resistance specification 101 is input, and a device characteristic database (resistance size dependence database) storing resistance value size dependence data. ) 109 (first device characteristic database) and a size examination unit 112 (first size examination unit).
[0087]
The resistance specification 101 from the specification input unit 102 is input to the layout constraint interpretation unit 103 in the size examination unit 112, where an initial value 104 of the size and an operation condition 105 are set. The initial value 104 is an initial value of the line width W and the line length L, and is determined by the contents of the design specification 101. The calculation condition 105 is an allowable range of the line width W and the line length L, which is also determined by the contents of the resistance specification 101.
[0088]
The resistance value at the initial value 104 of the line width W and the line length L is calculated by the resistance value calculation unit 106. The resistance value calculation unit 106 is linked with the resistance size dependency database 109. The current size proposal with the line width W and the line length L is output from the resistance value calculation unit 106 to the resistance size dependence database 109, and the resistance size dependence database 109 calculates the resistance value at the input W and L. Then, the calculation result is output to the resistance value calculation unit 106.
[0089]
The calculation result of the resistance value is immediately determined by the determination unit 107 as to whether or not the design specification 101 is satisfied. In this determination method, the difference between the calculation result of the resistance value and the target resistance value in the design specification 101 is calculated. If OK, the values of W and L are output as sizes, and the automatic device size determination processing ends.
[0090]
Generally, it is rare that the resistance specification 101 is satisfied by W and L at the initial value 104. If the determination unit 107 determines NO, the size correction unit 108 corrects the values of W and L according to a predetermined calculation method. This calculation method changes depending on the contents of the calculation condition 105.
[0091]
The corrected size is returned to the resistance value calculation unit 106 again. The loop of the resistance value calculation unit 106 → the determination unit 107 → the size correction unit 108 → the resistance value calculation unit 106 is repeated until the resistance specification 101 is satisfied. If it is determined in the internal processing of the size correction unit 108 that a resistor that satisfies the resistance specification 101 cannot be created, an error message is output as an error output 111, and the device size automatic determination process ends.
[0092]
Next, the layout constraint interpreting unit 103, the size correcting unit 108, and the resistance size dependency database 109 will be described in more detail.
[0093]
First, the layout constraint interpreting unit 103 will be described with reference to FIG. FIG. 2 is a diagram showing processing contents in the layout constraint interpretation unit 103 of FIG.
[0094]
In FIG. 2, in the layout constraint interpreting unit 103, first, the constraint-based branch processing unit 120 performs an area minimum time processing unit 121 branched into three according to the contents of the layout constraint in the resistance specification 101. The processing proceeds to a target processing unit of the processing unit 124 when the WL range is restricted and the processing unit 127 when there is no restriction.
[0095]
In the case of the constraint that the area is minimum, the processing proceeds to the area minimum processing unit 121, and from there, as a first initial value 122, W = minimum value (in the design rule), L = default (a predetermined value within the design rule range) Is output. Further, the minimum processing unit 121 outputs W = minimum value and L represents a design rule range as the first calculation condition 123. If there is no upper limit in the design rule, a predetermined numerical value (a numerical value based on a chip size or the like) is set by software, and this is set as the upper limit.
[0096]
In the following description, when there is no upper limit in the design rule, a similar upper limit value is set, and the upper limit is set as the design rule upper limit in the automatic size determination processing.
[0097]
The first initial value 122 and the first calculation condition 123 are output as the initial value 104 and the calculation condition 105 in the size examination unit 112, respectively.
[0098]
If there is a size restriction on both or one of W and L, the process proceeds to the WL range constraint processing unit 124. If only one of the upper and lower limits is specified, the value of the design rule is set as the upper limit or lower limit for the unspecified one. From the WL range constraint processing unit 124, as the second initial value 125, W = the minimum value within the W constraint range (default if W is not restricted), L = the minimum value within the L constraint range (W is not restricted) If it is the default) is output. In the present embodiment, the second initial value 125 is set as the minimum value within the restriction range, but any value may be used as long as the value is within the restriction range. In addition, from the WL range constraint time processing unit 124, as the second operation condition 126, W is a set constraint range (a design rule range when W is not restricted), and L is a set constraint range (L is not restricted). In this case, the design rule range is output.
[0099]
The second initial value 125 and the second operation condition 126 are output as the initial value 104 and the operation condition 105 in the size examination unit 112, respectively.
[0100]
If there are no restrictions on the design specifications for W and L, the processing proceeds to the processing section 127 when there is no restriction. The unconstrained processing unit 127 outputs W = default and L = default as the third initial value 128, and outputs W and L as design rule ranges as the third operation condition 129. The third initial value 128 and the third operation condition 129 are output as the initial value 104 and the operation condition 105 in the size examination unit 112, respectively.
[0101]
Next, the size correcting unit 108 in FIG. 1 will be described with reference to FIG. FIG. 3 is a diagram showing processing contents in the size correction unit 108 in FIG.
[0102]
In FIG. 3, in the size correction unit 108, first, the L size correction unit 130 performs L size correction. This correction method uses the ratio of the difference between the current W and L resistance values and the design specifications as calculated by the following formula, calculated by the determination unit 107.
[0103]
(Ratio of difference) = (Current resistance value at W and L) / (Specified resistance value)
The following calculation is set as L after correction.
[0104]
(Modified L) = (Current L) ÷ (Ratio of difference)
Next, the L size determination unit 131 checks whether the value of the corrected L is within the range of the calculation condition 105. The L size determination unit 131 outputs OK to the resistance value calculation unit 106 shown in FIG.
[0105]
If the corrected L value is out of the range of the calculation condition 105, the determination is NO, and the process proceeds to the L calculation range end setting unit 133. If the corrected L value exceeds the upper limit, the upper limit value of the calculation condition is set as the corrected L2. Conversely, if the lower limit has been cut, the lower limit of the calculation condition is set to L2 after correction.
[0106]
Further, the W size correction unit 134 performs additional W correction. The additional correction ratio is calculated by the following formula.
[0107]
(Additional correction ratio) = (L2 after correction) / (L after correction)
The following calculation is set as W after correction.
[0108]
(After correction W) = (current W) x (additional correction ratio)
Next, the W size determination unit 135 checks whether the value of the corrected W is within the range of the calculation condition 105. The W size determination unit 135 outputs OK if it is within the range, and outputs the corrected L2 and the corrected W as the corrected size 132.
[0109]
If the determination by the W size determination unit 135 is out of the range, the determination is NO, and the process proceeds to the W calculation range end setting unit 136. If the upper limit is exceeded, the upper limit value of the calculation condition is set to W2 after correction. Conversely, if the lower limit has been cut, the lower limit value of the calculation condition is set to W2 after correction.
[0110]
Next, the repetition determination unit 137 determines whether the data has been corrected from the previous time. If you have already taken the upper and lower limits at the previous stage, you cannot make any further corrections. When the value has been changed in either one of W and L, the repetition determination unit 137 outputs “OK” and the corrected L2 and the corrected W2 as the corrected size 132. On the other hand, when the correction has not been made, the determination is NO, and the repetition determination unit 137 outputs, as the error output 111, a message indicating that the resistance satisfying the specification cannot be realized.
[0111]
The value of the modified size 132 is sent to the resistance value calculating unit 106 in FIG. 1 as a new size candidate.
[0112]
Next, the resistance size dependency database 109 of FIG. 1 will be described with reference to FIG. FIG. 4 is a schematic diagram showing a data arrangement in a predetermined size range in the resistance size dependency database 109.
[0113]
The resistance size dependence database 109 stores data of resistance values R (W, L) under predetermined voltage conditions of any size permitted to be designed as a resistance element. In the present embodiment, the data of the resistance value itself in Ω is stored, but the data of the sheet resistance Rsh (W, L), which is the resistance value per unit sheet, is stored, and the resistance value is calculated by the following calculation. May be calculated in the form of
[0114]
R (W, L) = Rsh (W, L) × L ÷ W
Next, the storage format of these data will be described. Data is stored in a table map format. That is, as shown in FIG. 4, data of each size (the size indicated by ● in the figure) obtained by dividing a predetermined size range by a predetermined step is stored.
[0115]
Data of a size for which data is not directly stored is obtained by interpolation or extrapolation based on data of a close size.
[0116]
FIG. 5 is a schematic diagram illustrating an example of the interpolation calculation. As shown in FIG. 5, a description will be given of a method of calculating resistance value data when W1 <Wc <W2 and L1 <Lc <L2, where the resistance line width W = Wc and the resistance line length L = Lc. In FIG. 5, ● represents data stored in the database 109, and を represents data not stored in the database 109.
[0117]
Four adjacent size data of R (W1, L1), R (W2, L1), R (W1, L2), and R (W2, L2) stored in the resistance size dependency database 109 are used.
[0118]
In the first stage, two resistance values R (Wc, L1) and R (Wc, L2) are interpolated.
[0119]
In the second stage, the resistance value of the target R (Wc, Lc) is interpolated from two of R (Wc, L1) and R (Wc, L2).
[0120]
As the interpolation calculation formula, three formulas of the interpolation calculation formula (1) shown in FIG. 6 are used.
[0121]
Note that a method of interpolating and calculating two resistance values of R (W1, Lc) and R (W2, Lc) and interpolating the resistance value of the target R (Wc, Lc) from these two values may be used. Absent. In this case, three formulas of the interpolation formula (2) shown in FIG. 6 are used.
[0122]
If a database is constructed in the data storage format described above, a resistance value at an arbitrary size can be extracted.
[0123]
For some sizes, the resistance value may be calculated by extrapolation. However, the extrapolation calculation is not desirable because the accuracy is deteriorated. In particular, it is desirable to store data up to the minimum design rule size so that the extrapolation calculation is not required for a small size. On the larger size side, data up to a point where the characteristic change rate is constant and the accuracy of the extrapolation calculation does not decrease is necessary. Although this accuracy will be described in other embodiments, it can be dealt with by reflecting it on simulation accuracy data.
[0124]
Even if extrapolation calculation is necessary, if the person who stores the data in the database creates the extrapolation calculation data in advance before building the database and stores the data in the database, It is only necessary to register only the interpolation formula inside. That is, in FIG. 4, even when data of L = Lb does not originally exist, data of L = Lb may be created and registered by extrapolation calculation.
[0125]
As described above, according to the present embodiment, it is possible to automatically determine the size of the resistance element having the resistance value as specified.
[0126]
(Second embodiment)
FIG. 7 shows a device size for realizing a resistance element having a specified resistance value under a specified voltage condition in response to the fact that the characteristics of the resistance element have voltage dependency as a second embodiment of the present invention. FIG. 9 is a model diagram illustrating a configuration and a processing flow of an automatic determination processing unit 145.
[0127]
This embodiment is substantially the same as the configuration and the processing flow of the first embodiment shown in FIG. 1 except for the resistance specification 140, the specification input unit 141, and the resistance calculation unit in the size examination unit 144. 142 and a resistance size & voltage dependency database 143.
[0128]
The device size automatic determination processing unit 145 includes a specification input unit 141 (second specification input unit) to which the resistance specification 140 is input, and a database (resistance size) in which size dependence data and voltage dependence data of resistance values are stored. & Voltage dependency database) 143 (second device characteristic database) and a size examination unit 144 (second size examination unit).
[0129]
There are the following three resistance specifications 140.
[0130]
-Desired resistance value
・ Restrictions on layout
・ Terminal voltage condition V of resistance element
The layout constraint interpreting unit 103 plays the same role as that of FIG. 1 and also outputs the same initial value 104 and operation condition 105.
[0131]
In the resistance value calculation 142, the W and L initial values or corrected values and the voltage condition V included in the resistance specification 140 are input to the resistance size & voltage dependence database 143, and the resistance size & voltage dependence database 143 is input. Then, the resistance value under the corresponding condition is calculated and output to the resistance value calculation 142.
[0132]
Next, the resistance size & voltage dependency database 143 will be described in detail. This database 143 is stored in a format in which data of the resistance value R (W, L, V) under the voltage condition V in any operation range of any size permitted to be designed as a resistance element can be extracted. I have. In the present embodiment, the data of the resistance value itself in units of Ω is stored, but the data of the sheet resistance Rsh (W, L, V), which is the resistance value per unit number of sheets, is stored. The form in which the resistance value is calculated by calculation may be used.
[0133]
R (W, L, V) = Rsh (W, L, V) × L ÷ W
Next, the storage format of these data will be described. Data is stored in a table map format. That is, what size data should be stored may be the same as that described with reference to FIG. 4 in the first embodiment. As for the voltage condition V, data is provided at points where a predetermined voltage range is divided by a predetermined voltage step. That is, as shown in FIG. 8, this is an image in which size-dependent data is stored for each of a plurality of voltage conditions V1, V2,..., Va.
[0134]
The three conditions of W, L and V are independent of each other. A method of interpolating necessary data from a table map database of three or more independent conditions will be described. In this description, referring to FIG. 9, a case where there are three conditions X, Y, and Z for determining arbitrary characteristic data A instead of the resistance value R and the conditions W, L, and V in order to provide versatility. explain. Note that a supplementary explanation will be given for a case where there are four or more conditions.
[0135]
In FIG. 9, X1 <Xc <X2 (X = X1, X = X2 is the closest condition of X = Xc and stored in the database), Y1 <Yc <Y2 (Y = Y1, Y = Y2 is Y X = Zc <Zc <Z2 (where Z = Z1, Z = Z2 is the condition stored in the database with the closest condition of Z = Zc) = Xc, Y = Yc, and Z = Zc. Data A (Xc, Yc, Zc) is interpolated.
[0136]
The first data combination required is 2 ³ = 8. Then, all the eight data are stored in the database.
[0137]
In the first stage, two of the three conditions are fixed to a common condition, and an intermediate interpolated value is obtained for the remaining one condition. Since there are four ways to fix the two conditions, four intermediate interpolated values are created. Which of the two conditions among X, Y, and Z is fixed is free. In FIG. 9, an intermediate interpolated value (part 1) at Z = Zc with respect to the Z condition is obtained from a combination where X and Y are equal. FIG. 10 shows the interpolation formula. A (Z1) means A (X1 or X2, Y1 or Y2, Z1), A (Z2) means A (X1 or X2, Y1 or Y2, Z2), and if A (Z1) and X = X1, then A If (Z2), X = X1, and if X = X2 in A (Z1), then X = X2 even in A (Z2). If A = (Z1) and Y = Y1, then A = (Z2) and Y = Y1. If A (Z1) and Y = Y2, then Y = Y2 even if A (Z2). The idea of the calculation formula is interpolation by a linear equation as shown in FIG. The interpolation is calculated from the slope of the graph and the amount of change in Z. This calculation method is used to perform the interpolation calculation between the data that appears many times after that and all of the conditions other than one of the plurality of conditions match.
[0138]
In the second stage, from the four intermediate interpolation values calculated in the first stage (one condition is fixed), an intermediate interpolation value for one of the conditions is further obtained. This results in two more interpolated values. In FIG. 9, when the conditions of X and Z are common (the Z condition is already fixed at Z = Zc), an intermediate interpolation value (part 2) at Y = Yc where Y1 <Y <Y2 is obtained.
[0139]
As a result, two intermediate interpolation values where Y = Yc and Z = Zc are obtained.
[0140]
In the third stage, an interpolated value for the remaining one condition is further obtained from the two intermediate interpolated values calculated in the second stage (the two conditions are already fixed). This is the target data A (Xc, Yc, Zc). In FIG. 9, when the conditions of Y and Z are made common (already fixed at Y = Yc and Z = Zc), an interpolated value at X = Xc where X1 <X <X2 is obtained.
[0141]
As described above, necessary data is obtained by interpolation from the database stored in the table map format for the three conditions.
[0142]
Further, this method can cope with any number of conditions for determining the characteristics. If there is only one condition, only the part shown in the third stage of FIG. 9 may be used. When there are two types of conditions, the portions shown in the second and third stages in FIG. 9 may be used.
Conversely, when the number of conditions increases, the number of data required in the first stage of the interpolation calculation from the data stored in the database is doubled for each additional condition. In addition, the number of steps of the interpolation calculation increases by one step. The procedure is the same, and the condition may be selected in order, and the process of calculating the intermediate interpolation value at the target value of the selected condition may be repeated.
[0143]
In the case of the resistance calculation to be described in the present embodiment, three conditions for determining the characteristics are the resistance line width W, the resistance line length L, and the voltage condition V. Each can be applied to any of the X, Y, and Z just described. That is, there is not one calculation method.
[0144]
Although the voltage condition was specified as the specification and the voltage dependency data was stored in the database, the current condition could be specified as the specification and the current dependency data could be stored in the database instead. Absent.
[0145]
Note that depending on the structure of the resistance element, the characteristics may change not only under the voltage condition V between terminals of the device but also under other voltage conditions. If there are two voltage conditions, processing is performed assuming that there are a total of four conditions, and data can be obtained by the method described in the present embodiment.
[0146]
If the number of voltage conditions increases, it means that the resistance specification 140 itself changes. Therefore, the specification input unit 141 can also cope with all the condition numbers. In addition, the resistance calculation unit 142 can cope with the condition number input to the database.
[0147]
In FIG. 7, portions that are not described after the determination unit 107 are the same as those described in the first embodiment.
[0148]
As described above, according to the present embodiment, it is possible to automatically determine the size of the resistance element having the specified resistance under the specified voltage condition or current condition.
[0149]
(Third embodiment)
FIG. 12 shows a device size for realizing a resistance element having a resistance value as specified under a specified temperature condition in response to the fact that the characteristics of the resistance element have temperature dependence in the third embodiment of the present invention. FIG. 9 is a model diagram illustrating a configuration and a processing flow of an automatic determination processing unit 155.
[0150]
This embodiment is almost the same as the configuration and the processing flow of the second embodiment shown in FIG. 7 except for the resistance specification 150, the specification input unit 151, and the resistance calculation unit in the size examination unit 154. 152 and the resistance size & temperature dependency database 153.
[0151]
The device size automatic determination processing section 155 includes a specification input section 151 (third specification input section) to which the resistance specification 150 is input, and a database (resistance size) storing size dependence data and temperature dependence data of resistance values. & Temperature dependence database) 153 (third device characteristic database) and a size study unit 154 (third size study unit).
[0152]
There are the following three resistance specifications 150.
[0153]
-Desired resistance value
・ Restrictions on layout
・ Temperature condition T of resistance element
The layout constraint interpreting unit 103 plays the same role as that of FIG. 1 and also outputs the same initial value 104 and operation condition 105.
[0154]
The resistance value calculation unit 152 inputs the W and L initial values or the corrected values and the temperature condition T included in the specification to the resistance size & temperature dependency database 153. , And calculates the resistance value under the corresponding condition, and outputs the calculated resistance value to the resistance value calculation unit 152.
[0155]
Next, the resistance size & temperature dependency database 153 will be described in detail. This database 153 is stored in such a format that data of the resistance value R (W, L, T) can be extracted under temperature conditions in any operation range of any size permitted to be designed as a resistance element. . In the present embodiment, the data of the resistance value itself in Ω is stored, but the data of the sheet resistance Rsh (W, L, T), which is the resistance value per unit number of sheets, is stored and calculated by the following calculation. The form in which the resistance value is calculated may be used.
[0156]
R (W, L, T) = Rsh (W, L, T) × L ÷ W
Next, the storage format of these data will be described. Data is stored in a table map format. That is, what size data should be stored may be the same as that described in the first embodiment with reference to FIG. Regarding the temperature condition, data is provided at points where a predetermined temperature range is divided by a predetermined temperature step. That is, as shown in FIG. 13, this is an image in which size-dependent data is stored for each of a plurality of temperature conditions.
[0157]
The three conditions of W, L, and T are independent of each other. The data interpolation calculation method under necessary conditions is as described in the second embodiment with reference to FIGS. 9, 10, and 11. FIG.
[0158]
In FIG. 12, portions that are not described after the determination unit 107 are the same as those described in the first embodiment.
[0159]
As described above, according to the present embodiment, it is possible to automatically determine the size of the resistance element having the specified resistance under the specified temperature condition.
[0160]
(Fourth embodiment)
FIG. 14 shows a fourth embodiment of the present invention, in which a resistance element having a resistance value as specified under a specified allowable variation amount condition in response to the fact that the characteristic of the resistance element has a size dependence of the variation amount. FIG. 9 is a model diagram showing a configuration and a processing flow of a device size automatic determination processing unit 167 for realizing the above.
[0161]
This embodiment has a considerable portion in common with the configuration and the processing flow of the first embodiment shown in FIG. 1, and is largely different from the first embodiment in that a process for modifying the initial value 104 and the calculation condition 105 is added. It is in the point. Related to this processing are the variation data analysis unit 162, the resistance variation size dependence database 165 associated therewith, the correction initial value 163, and the correction calculation condition 164.
[0162]
The other differences are a resistance specification 160 and a specification input unit 161.
[0163]
The device size automatic determination processing unit 167 includes a specification input unit 161 (fourth specification input unit) to which the resistance specification 160 is input, a resistance size dependency database 109 (first device characteristic database), and a variation in resistance value. It is composed of a database (a resistance variation size dependence database) 165 (a fourth device characteristic database) in which the size dependence data of the amount is stored, and a size examination unit 166 (a fourth size examination unit).
[0164]
There are the following three resistance specifications 160.
[0165]
-Desired resistance value
・ Restrictions on layout
・ Allowable variation amount condition D
A ratio (percent) is appropriate as a unit of the allowable variation amount condition D in this case.
[0166]
The layout constraint interpreting unit 103 plays the same role as that of FIG. 1 and also outputs an initial value 104 and a calculation condition 105 having the same contents.
[0167]
Next, the variation data analysis unit 162 based on the allowable variation amount condition D input as the resistance specification 160 and the size dependence data of the variation amount of the resistance value stored in the resistance variation size dependence database 165. Then, the size condition of the resistance element satisfying the allowable amount is obtained. This condition is a calculation condition obtained from the allowable variation amount condition D, and can be obtained by comparing the size dependency data of the variation amount for each size with the allowable variation amount condition D.
[0168]
FIG. 15 is a diagram showing the size dependence of the variation amount, and indicates in which size region the variation amount D is within a certain range. When W × L is small, the variation amount is large, and only the variation amount within D1% (region A1) can be realized. If the size is slightly larger than this, a variation amount within D2% (region A2) smaller than D1 can be realized. In a region having a larger size, the variation amount becomes smaller within D3% (region A3) and within D4% (region A4). This data is stored in the resistance variation size dependence database 165. In FIG. 15, the amount of variation is divided into four steps, but the method of division may be any number of steps and the step width between each step may be any number. Further, the unit representing the amount of variation is set as a percentage, but any unit that can be an index of the amount of variation may be used. However, it is necessary to select a unit that is the same as the input unit of the allowable variation or that can be converted.
[0169]
The variation data analysis unit 162 further calculates the calculation conditions from the two calculation conditions 105 obtained from the constraints on the layout and the calculation conditions 162 ′ newly obtained by the variation data analysis unit 162 from the allowable variation amount condition. Make corrections. As shown in FIG. 16, a region that simultaneously satisfies the calculation condition 105 obtained from the layout constraint and the calculation condition 162 ′ obtained from the allowable variation amount condition is output as the corrected calculation condition 164.
[0170]
However, when both calculation conditions completely match, the condition of the calculation condition 105 is output as the modified calculation condition 164 without being changed.
[0171]
If there is no region that satisfies both the calculation conditions at the same time, an error message indicating that a resistor satisfying the specification cannot be realized is output as an error output 111, and the automatic device size determination processing ends immediately.
[0172]
Also, as shown in FIG. 16, when the initial value 104 is out of the modified operation condition 164, the initial value is modified to the size within the modified operation condition, and the result is output as the modified initial value 163. If the initial value 104 is already within the correction operation condition 164, there is no need to change it, and the initial value 104 is output as it is as the corrected initial value 163.
[0173]
The configuration after the resistance value calculation unit 106 is the same as that of the first embodiment except that the calculation conditions used in the size correction unit 108 are changed from the calculation conditions 105 to the correction calculation conditions 164.
[0174]
As described above, according to the present embodiment, it is possible to automatically determine the size of the resistance element having the resistance value as specified after reflecting the allowable variation amount condition.
[0175]
(Fifth embodiment)
FIG. 17 shows, as a fifth embodiment of the present invention, a resistance element having a resistance value as specified under a specified allowable mismatch amount condition in response to the fact that the characteristics of the resistance element have a size dependence of the mismatch amount. FIG. 9 is a model diagram showing a configuration and a processing flow of a device size automatic determination processing unit 175 for realizing.
[0176]
This embodiment is almost the same as the configuration and the processing flow of the fourth embodiment shown in FIG. 14 except for the resistance specification 170, the specification input unit 171, and the mismatch data analysis unit in the size examination unit 174. 172 and a resistance mismatch size dependence database 173 linked to the mismatch data analysis unit 172.
[0177]
The device size automatic determination processing unit 175 includes a specification input unit 171 (fifth specification input unit) to which the resistance specification 170 is input, a resistance size dependency database 109 (first device characteristic database), and a mismatch between resistance values. It is composed of a database (resistance mismatch size dependence database) 173 (fifth device characteristic database) storing the size dependence data of the quantity, and a size examination unit (fifth size examination unit).
[0178]
There are the following three resistance specifications 170.
[0179]
-Desired resistance value
・ Restrictions on layout
-Allowable mismatch amount condition MD
Percent is appropriate in this case as a unit of the allowable mismatch amount condition.
[0180]
The constraint interpreting unit 103 on the layout plays the same role as in the first embodiment, and also outputs the initial value 104 and the operation condition 105 having the same contents.
[0181]
Next, the mismatch data analysis unit 172, based on the allowable mismatch amount condition MD input as the specification and the size dependency data of the mismatch amount of the resistance value stored in the resistance mismatch size dependency database 173, The size condition of the resistance element that satisfies the allowable amount is obtained. This condition is a calculation condition obtained from the allowable mismatch amount condition MD, and can be obtained by comparing the size dependency data of the mismatch amount for each size with the allowable mismatch amount condition.
[0182]
FIG. 18 is a diagram showing the size dependence of the mismatch amount. The mismatch amount has the same size dependence as the variation amount shown in FIG. In FIG. 18, as a region where the mismatch amount DM decreases as the size increases (DM1>DM2> DM3), a region B1 that satisfies the mismatch amount DM1% or less, a region B2 that satisfies the mismatch amount DM2% or less, and a mismatch amount DM3% or less. Is divided into four stages, that is, the region B3 satisfying the condition and the region B4 satisfying the mismatch amount of less than 4%, and the dividing method may be any number of stages and the step width between the stages may be any number. However, the mismatch amount is smaller than the variation amount. This data is stored in the resistance mismatch size dependence database 173.
[0183]
The mismatch data analysis unit 172 further calculates the operation condition 105 obtained from the layout constraint and the allowable mismatch amount condition newly obtained by the mismatch data analysis unit 172, similarly to the variation data analysis unit 162 in the fourth embodiment. Based on the two obtained calculation conditions, the calculation condition and the initial value are corrected, and the result is output as the corrected calculation condition 164 and the corrected initial value 163.
[0184]
If there is no region that satisfies both the calculation conditions at the same time, an error message indicating that a resistor satisfying the specification cannot be realized is output as an error output 111, and the automatic device size determination processing ends immediately.
[0185]
The steps after the resistance value calculation unit 106 are the same as those in the fourth embodiment.
[0186]
As described above, according to the present embodiment, it is possible to automatically determine the size of the resistance element having the resistance value as specified after reflecting the allowable mismatch amount condition.
[0187]
(Sixth embodiment)
FIG. 19 shows, as a sixth embodiment of the present invention, a resistance element having a resistance value as specified under a specified allowable simulation error condition in response to the fact that the characteristic of the resistance element has a size dependence of a simulation error. FIG. 19 is a model diagram showing a configuration and a processing flow of a device size automatic determination processing unit 185 for realizing the processing.
[0188]
This embodiment has substantially the same configuration and the same processing flow as the fourth embodiment shown in FIG. 14 and the fifth embodiment shown in FIG. 17, except for the resistance specification 180 and the specification input unit 181. And a simulation error analysis unit 182 in the size examination unit 184 and a resistance simulation error size dependence database 183 linked to the simulation error analysis unit 182.
[0189]
The device size automatic determination processing unit 185 includes a specification input unit 181 (sixth specification input unit) to which the resistance specification 180 is input, a resistance size dependency database 109 (first device characteristic database), and a simulation of a resistance value. The database includes a database (resistance simulation error size dependency database) 183 (sixth device characteristic database) in which error size dependency data is stored, and a size examination unit (sixth size examination unit).
[0190]
There are the following three resistance specifications 180.
[0191]
-Desired resistance value
・ Restrictions on layout
・ Allowable simulation error condition E
Percent is appropriate in this case as a unit of the allowable simulation error condition E.
[0192]
The constraint interpreting unit 103 on the layout plays the same role as in the first embodiment, and also outputs the initial value 104 and the operation condition 105 having the same contents.
[0193]
Next, the simulation error analysis unit 182 is based on the allowable simulation error condition E input as the specification and the size dependence data of the simulation error of the resistance value stored in the resistance simulation error size dependence database 183. Then, the size condition of the resistance element satisfying the allowable amount is obtained. This condition is a calculation condition obtained from the allowable simulation error condition, and can be obtained by comparing the size dependence data of the simulation error for each size with the allowable simulation error condition E.
[0194]
FIG. 20 is a diagram illustrating the size dependence of the simulation error. In FIG. 20, as a region where the simulation error E varies depending on the size (E1>E2> E3), a region C1 satisfying the simulation error E1% or less, a region C2 satisfying the simulation error E2% or less, and a simulation error E3% or less are satisfied. Although the area C3 is divided into three steps, the division may be performed in any number of steps and the step width between the steps may be set to any number. This data is stored in the resistance simulation error size dependency database 183.
[0195]
The simulation error analysis unit 182 further includes, similarly to the variation data analysis unit 162 according to the fourth embodiment, and the mismatch data analysis unit 172 according to the fifth embodiment, calculation conditions obtained from layout constraints and simulations. The calculation condition and the initial value are corrected from two calculation conditions obtained from the allowable simulation error condition newly obtained by the error analysis unit 182, and the result is output as a correction calculation condition 164 and a corrected initial value 163.
[0196]
If there is no region that satisfies both the calculation conditions at the same time, an error message indicating that a resistor satisfying the specification cannot be realized is output as an error output 111, and the automatic device size determination processing ends immediately.
[0197]
The steps after the resistance value calculation unit 106 are the same as those in the fourth embodiment.
[0198]
As described above, according to the present embodiment, it is possible to automatically determine the size of the resistance element having the resistance value as specified after reflecting the allowable simulation error condition.
[0199]
(Seventh embodiment)
In the first to sixth embodiments, the size dependence of the resistance value, the voltage dependence, the temperature dependence, the size dependence of the variation amount, the size dependence of the mismatch amount, and the size dependence of the simulation error are individually described. The processing for automatically determining the size of the resistance element having the resistance value as specified has been described in consideration. In the seventh embodiment of the present invention, a description will be given of a process of automatically determining the size of a resistance element having a resistance value as specified by simultaneously considering all of the above.
[0200]
FIG. 21 shows, as a seventh embodiment of the present invention, size dependency of resistance value, voltage dependency, temperature dependency, size dependency of variation, size dependency of mismatch, and size dependency of simulation error. FIG. 11 is a model diagram showing a configuration and a processing flow of an automatic device size determination processing unit 196 that realizes a resistance element having a resistance value as specified in consideration of FIG.
[0201]
The device size automatic determination processing unit 196 includes a specification input unit 191 (seventh specification input unit) to which the resistance specification 190 is input, the size dependence data, the voltage dependence data, the temperature dependence data, and the variation amount of the resistance element. (Resistive characteristic database) 194 (seventh device characteristic database) storing the size dependence data of the mismatch size, the size dependence data of the mismatch amount, and the size dependence data of the simulation error, and the size examination unit 195 (the seventh Size study section).
[0202]
The resistance specification 190 has the following seven types. These are input to the specification input unit 191.
[0203]
-Desired resistance value
・ Restrictions on layout
-Voltage condition V between terminals of resistive element (including multiple voltages)
Alternatively, the current condition A (including the case of a plurality of currents)
(Including the case where the voltage condition V and the current condition A are combined)
・ Temperature condition T of resistance element
・ Allowable variation amount condition D
-Allowable mismatch amount condition MD
・ Allowable simulation error condition E
If there are no special restrictions on the allowable variation amount condition D, the allowable mismatch amount condition DM, and the allowable simulation error condition E, a predetermined default value is automatically input.
[0204]
The initial value & operation condition determination unit 192 outputs an initial value 104 and an operation condition 105 based on four conditions of a layout constraint, an allowable variation amount condition D, an allowable mismatch amount condition MD, and an allowable simulation error condition E. As shown in FIG. 22, from these conditions, as shown in FIG. 22, the operation condition 105 ′ obtained from the layout constraint, the operation condition 162 ′ obtained from the allowable variation amount condition D, and the operation condition 172 ′ obtained from the allowable mismatch amount condition MD , An operation condition 182 ′ obtained from the allowable simulation error condition E is obtained. The concept of these four calculation conditions is as already described in the first to sixth embodiments. Information necessary for obtaining the calculation condition is obtained from the resistance characteristic database 194. The initial value & calculation condition determination unit 192 determines and outputs a region satisfying all four conditions as the final calculation condition 105, and also determines and outputs a value within this calculation condition as the initial value 104.
[0205]
In the resistance characteristic database 194, all the device information described in the first to sixth embodiments, that is, as shown in FIG. 23, size dependence data of resistance, voltage (or current) dependence data, temperature The dependency data, the size dependency data of the variation amount, the size dependency data of the mismatch amount, and the size dependency data of the simulation error are stored.
[0206]
The resistance value calculation unit 193 inputs the initial values of W and L, the voltage condition and the temperature condition input as the resistance specification 190 to the resistance characteristic database 194, and the resistance characteristic database 194 displays the resistance value under that condition. Is calculated and output to the resistance value calculation unit 193.
[0207]
The processing after the determination unit 107 in the size examination unit 195 is the same as in the first to sixth embodiments.
[0208]
As described above, according to the present embodiment, it is possible to automatically determine the size of the resistive element having the specified resistance value while simultaneously considering all specifications.
[0209]
Note that a configuration may be adopted in which any one of the voltage condition V (including a plurality of cases), the temperature condition T, the allowable variation amount condition D, the allowable mismatch amount condition DM, and the allowable simulation error condition E is not processed. . FIG. 22 is used to change the specification input unit 191 according to the conditions to be considered and to eliminate any of the allowable variation amount condition D, the allowable mismatch amount condition DM, and the allowable simulation error condition E. If the number of overlapping items described above is reduced and the voltage condition V (including a plurality of cases) and the temperature condition T are not considered, the configuration of the resistance value calculation unit 193 is changed. Further, unnecessary data may be deleted from the resistance characteristic database 194.
[0210]
(Eighth embodiment)
In the first to seventh embodiments, the processing for automatically determining the size of the resistance element made of one type of material has been described. In the eighth embodiment of the present invention, when there are a plurality of options for the material of these resistive elements, after comparing them, an optimum material for realizing a resistive element having a resistance value as specified and its resistance are determined. A process for automatically determining the element size will be described.
[0211]
FIG. 24 is a diagram illustrating the automatic device size determination processing unit 196 that realizes a resistance element having a resistance value as specified when there are two types of material choices, the A device and the B device, according to the eighth embodiment of the present invention. It is a model figure which shows a structure and a flow of a process. In the present embodiment, basically, the processes described in the first to seventh embodiments are separately executed for two types of materials of the A device and the B device, and the results are compared and determined. Take a configuration with additional processing.
[0212]
According to the resistance specification 200, a desired resistance value and constraints on the layout (L and W ranges), a voltage condition V (including a plurality of cases), a temperature condition T, an allowable variation amount condition D, an allowable mismatch amount condition DM, and an allowable simulation. An error condition E is specified. These specifications are input to the specification input unit 201. When there are no special restrictions on the voltage condition V (including a plurality of cases), the temperature condition T, the allowable variation amount condition D, the allowable mismatch amount condition DM, and the allowable simulation error condition E, a predetermined default value is automatically input. Is done.
[0213]
Next, it is divided into an A device automatic size determination processing unit 202 and a B device automatic size determination processing unit 202, both of which are the same as the size examination unit 195 described with reference to FIG. 21 in the seventh embodiment. The one that has the function and is different is a database to be referred to. The A device size automatic determination processing unit 202 refers to the A device database 203, and the B device size automatic determination processing unit 205 refers to the B device database 206 to perform processing.
[0214]
The size determined by the process of the A device size automatic determination processing unit 202 is output as a result output A204. In the case of an error, the fact that the error has occurred is output as a result output A204.
[0215]
The size determined by the process in the B device size automatic determination processing unit 205 is output as a result output B207. In the case of an error, an error is output as a result output B207.
[0216]
Next, the result output A204 and the result output B207 are compared by the comparing unit 208. If both are not errors, the material is selected according to a predetermined rule, and the selected material and its size are output as the size output 209. As the selection rule, there is a method of selecting one having a smaller size, and in the case where both can be realized, preferentially selecting the device A. In addition, the user may be allowed to make a selection.
[0219]
When one of the result output A 204 and the result output B 207 has an error, the one that does not have an error is selected, and the selected material and its size are output as the size output 209.
[0218]
If both the result output A 204 and the result output B 207 are in error, an error message is output as the error output 210.
[0219]
As described above, according to the present embodiment, when there are a plurality of options for the material of the resistance element, the optimum material for realizing the resistance element having the resistance value as specified and the size of the resistance element are automatically determined. be able to.
[0220]
(Ninth embodiment)
In the first to eighth embodiments, examples have been described in which data is stored in the device characteristic database in a table map format. In the ninth embodiment of the present invention, a method will be described in which device characteristic data is represented by a model formula using a mathematical function and stored in a database in the form of the model formula.
[0221]
By expressing the resistance value model of the resistance element as a function R (W, L, V, T) of the device size, the voltage condition, and the temperature condition, a relatively accurate model can be configured. FIG. 25 is a schematic diagram showing the contents of the resistance characteristic database 194 'using such a model formula. In FIG. 25, Ra, Rb, Rc, dW, dL, param_v1, param_v2, param_t1, and param_t2 are model parameters. R0 (W, L) means a resistance value when the temperature T is the normal temperature Tnom and the voltage V is zero. Vfact is a voltage-dependent coefficient and is a quadratic function with respect to voltage. Tfact is a temperature-dependent coefficient and is a quadratic function with respect to temperature.
[0222]
This model formula is an example, and other forms may be used. If the bias condition increases, it is sufficient to make an equation according to it. Here, it is significant that the function is a function of size, voltage (current may be used), and temperature.
[0223]
As described above, according to the present embodiment, there is no need for interpolation calculation as in the case of the table map method, and the data amount can be significantly reduced. On the other hand, there is a difference between the measured data of the device itself and the model formula, which may be reflected in the size dependence data of the simulation error. Note that the simulation accuracy depends on the form of the function of the model formula and the extraction accuracy of the model parameters.
[0224]
(Tenth embodiment)
In the first to ninth embodiments, the processing for automatically determining the size of the resistance element has been described. However, these configurations can also be applied to a capacitor by partially changing the processing. This will be described as a tenth embodiment of the present invention.
[0225]
In a capacitive element using a parallel plate portion, the vertical length and the horizontal length of the layout usually have no difference in characteristics, but for convenience, the vertical length is defined as L and the horizontal length is defined as W. The reverse is acceptable.
[0226]
The entire process of automatically determining the size of the capacitive element will be described later with reference to FIG. 30, and will be described first from the point that it is significantly different from the case of the resistive element.
[0227]
Differences in the size dependence of the resistance element and the capacitance element are as follows.
[0228]
Resistance value of resistance element: approximately proportional to resistance line length L
Inversely proportional to resistance line width W
Capacitance value of capacitive element: proportional to both L and W
Therefore, the following two processes need to be performed by a method different from the case of the resistance element.
[0229]
(1) Processing for determining initial values and operation conditions from layout constraints
(2) Processing to correct the size
In the case where the initial values and the calculation conditions are determined from the layout constraints, the description of the first embodiment has been given with reference to FIG. FIG. 26 shows the processing contents for the capacitance element in place of this.
[0230]
First, the constraint-specific branch processing unit 221 performs a minimum-area processing unit 222, a WL-range-constrained processing unit 225, and a no-restriction processing unit 225 that are branched into three according to the contents of the layout restrictions in the resistance specification 101. The process proceeds to the target processing unit of the time processing unit 228.
[0231]
In the case of the constraint that the area is minimum (the case where W = L is also applicable), the processing proceeds to the area minimum processing unit 222, and the first initial value 223 is set to W = default (the value within the design rule range). (Predetermined numerical value), L = W is output, and as the first calculation condition 224, a range exclusive for W = L is output. This applies this same range to both W and L.
[0232]
As the lower limit of the exclusive range when W = L, the larger of the lower limit of W and the lower limit of L in the design rule is used. In addition, as the upper limit of the exclusive range when W = L, the smaller of the upper limit of W and the upper limit of L in the design rule is used.
[0233]
The first initial value 223 and the first operation condition 224 are output as an initial value 232 obtained from a layout restriction and a calculation condition 233 obtained from a layout restriction, respectively.
[0234]
If there is a size constraint on both or one of W and L, the process proceeds to the WL range constraint-time processing unit 225. If only one of the upper and lower limits is specified, the value of the design rule is set as the upper limit or lower limit for the unspecified one. From the WL range constraint processing unit 225, as the second initial value 226, W = the minimum value within the constraint range (default when there is no constraint on W), L = the minimum value within the constraint range (the constraint on W If not, the default is output. In the present embodiment, the second initial value 226 is the minimum value within the restricted range, but any value within the restricted range may be used. Further, from the WL range constraint processing unit 225, as the second operation condition 227, W is a set constraint range (a design rule range if W is not restricted), and L is a set constraint range (L is not restricted). In this case, the design rule range is output.
[0235]
The second initial value 226 and the second operation condition 227 are output as an initial value 232 obtained from a layout restriction and a calculation condition 233 obtained from a layout restriction, respectively.
[0236]
If there are no constraints on the design specifications for W and L, the process proceeds to the unconstrained processing unit 228. The unconstrained processing unit 228 outputs W = default and L = default as the third initial value 229, and outputs the design rule range for W and L as the third calculation condition 230. The third initial value 229 and the third calculation condition 230 are output as an initial value 232 obtained from the layout constraint and a calculation condition 233 obtained from the layout constraint, respectively.
[0237]
In the case of correcting the size, the description of the resistance element has been described in the first embodiment with reference to FIG. FIG. 27 shows the processing contents of the capacitive element in place of this.
[0238]
In the case of a capacitive element, it is necessary to divide it into two size correction processes due to layout restrictions. Therefore, first, in the case of the constraint that the area is minimum (this is also the case when W = L is desired) by the calculation method branching unit 235, the processing is advanced to the W = L calculation unit 236, and the other processing is performed. In this case, the process proceeds to the W ≠ L operation unit 237.
[0239]
Next, the size correction process in the W = L calculation unit 236 will be described with reference to FIG. First, the WL size correction unit 240 corrects both the sizes of W and L. The correction method uses the difference ratio as in the case of FIG.
[0240]
(Ratio of difference) = (Capacity value at current W and L) / (Capacity value of specification)
The following calculation is set as W after correction (or L after correction). The difference from the case of FIG. 3 is that the square root of the difference ratio is used. Although the ratio of the difference may be used as it is, it is not preferable because the number of corrections increases.
[0241]
(Corrected W) = (current W) ÷ (square root of difference ratio)
(After modification L) = (After modification W)
Next, the WL size determination unit 241 checks whether the values of the corrected W and the corrected L are within the range of the calculation condition 264 in the entire process illustrated in FIG. If it is within the range, it is OK, and the corrected W and the corrected L are output as the corrected size 238 in FIG.
[0242]
On the other hand, if it is out of the range, the determination is NO, and the process proceeds to the calculation range end setting unit 242.
[0243]
If it exceeds the upper limit, the upper limit value of the calculation condition is set to W2 after correction. It is also assumed that L2 after correction = W2 after correction.
[0244]
If the lower limit has been cut, the lower limit of the calculation condition is set to W2 after correction. It is also assumed that L2 after correction = W2 after correction.
[0245]
Next, the repetition determination unit 243 determines whether the corrected W2 has been corrected from the previous time. If you have already taken the same value as the previous one, no further correction is possible. If the value has been changed, the corrected W2 and the corrected L2 are output as OK as the corrected size 238 in FIG. If the correction has not been made, a message indicating that a resistor satisfying the specification cannot be realized is output as the error output 270 in FIG. 30, and all the processing ends. This is the end of the description of FIG.
[0246]
Next, a description will be given of the size correction process in the W ≠ L operation unit 237 of FIG. 27 with reference to FIG. First, the L size correction unit 250 corrects the size of L. The correction method uses the difference ratio as in the case of FIG.
[0247]
(Ratio of difference) = (Capacity value at current W and L) / (Capacity value of specification)
The following calculation is set as L after correction. Unlike the case of the processing in the W = L operation unit 236, the difference ratio is used as it is.
[0248]
(Modified L) = (Current L) / (Ratio of difference)
Next, the L size determination unit 251 checks whether the value of the corrected L is within the range of the calculation condition 264 in FIG. If it is within the range, it is OK, and the corrected L is output as the corrected size 238 in FIG.
[0249]
On the other hand, if it is out of the range, the determination is NO, and the process proceeds to the L calculation range end setting unit 252.
[0250]
If the upper limit is exceeded, the upper limit value of the calculation condition is set to L2 after correction.
[0251]
If the lower limit has been cut, the lower limit of the calculation condition is set to L2 after correction.
[0252]
Further, a W size correction unit 253 performs additional W correction. The additional correction ratio is calculated by the following calculation.
[0253]
(Additional correction ratio) = (L2 after correction) / (L after correction)
The following calculation is set as W after correction. The difference from the case of FIG. 3 is that division is performed instead of multiplication.
[0254]
(After correction W) = (Current W) / (Additional correction ratio)
Next, the W size determination unit 254 checks whether the value of the corrected W is within the range of the calculation condition 264. If it is within the range, it is OK, and the corrected L2 and the corrected W are output as the corrected size 238.
[0255]
On the other hand, if the value is out of the range, NO is determined, the process proceeds to the W calculation range end setting unit 255, and if the value exceeds the upper limit, the upper limit value of the calculation condition is corrected to W2, and conversely, the lower limit is cut. Sets the lower limit value of the calculation condition to W2 after correction.
[0256]
Next, the repetition determination unit 243 determines whether one of the corrected L2 and the corrected W2 has been corrected from the previous time. If both already have the same value as the previous one, no further correction is possible. If the value has been changed, the modified W2 and the modified L2 are output as the modified size 238 as OK. If the correction has not been made, a message to the effect that a resistor satisfying the specification cannot be realized is output as an error output 270, and all processing ends. This is the end of the description of FIG.
[0257]
The corrected size 238 in FIG. 27 is sent to the capacity value calculation unit 265 in FIG. 30, and the size correction ends.
[0258]
FIG. 30 is a model diagram illustrating a configuration and a processing flow of the device size automatic determination processing unit 272 that automatically determines the size of the capacitive element. The basic concept is the same as that of the resistance element. The specification changes from the resistance specification to the capacitance specification 260, and the difference is that the desired resistance value becomes the capacitance value. Layout constraints, voltage conditions, temperature conditions, allowable variation amount conditions, allowable mismatch amount conditions, and allowable simulation error conditions can be processed in the same manner as in the case of the resistance element.
[0259]
The capacity characteristic database 266 is used as the device characteristic database. As in the case of the resistance value of the resistance element, the capacitance characteristic database 266 stores the size dependence data, the voltage dependence data, the temperature dependence data, the size dependence data of the variation amount, and the mismatch amount regarding the capacitance value of the capacitance element. And the size dependence data of the simulation error are stored. FIG. 31 is a schematic diagram showing the data contents of the capacitance characteristic database 266. The size dependence, voltage dependence, and temperature dependence are expressed in the form of a capacitance model expression C (W, L, V, T). Data is stored. In FIG. 31, Ca, Cb, dW, dL (usually dL = dW), param_vc1, param_vc2, param_tc1, and param_tc2 are model parameters. C0 (W, L) means a capacitance value when the temperature T is the normal temperature Tnom and the voltage V is zero. Vfact is a voltage-dependent coefficient and is a quadratic function with respect to voltage. Tfact is a temperature-dependent coefficient and is a quadratic function with respect to temperature.
[0260]
Note that this capacitance value model formula is an example, and other forms may be used.
[0261]
Note that a database in a table map format may be used without using the model formula.
[0262]
The above is the description of the capacity characteristic database 266.
[0263]
Returning to FIG. 30, there are the following seven types of capacity specifications 260. These are input to the specification input unit 261.
[0264]
-Desired capacitance value
・ Restrictions on layout
・ Voltage V between terminals of the capacitive element (including the case of multiple voltages)
・ Temperature condition T of capacitive element
・ Allowable variation amount condition D
-Allowable mismatch amount condition MD
・ Allowable simulation error condition E
If there are no special restrictions on the allowable variation amount condition D, the allowable mismatch amount condition DM, and the allowable simulation error condition E, a predetermined default value is automatically input.
[0265]
Next, the initial value & calculation condition determining unit 262 determines the initial value 263 and the calculation condition 264 in conjunction with the capacity characteristic database 266 in the same manner as described with reference to FIG. 22 in the seventh embodiment. . The calculation conditions obtained from the layout restrictions use the method of FIG. 26 described above.
[0266]
Next, the capacitance value calculation unit 265 calculates the capacitance value at the specified size under the specified voltage condition and temperature condition in conjunction with the capacitance characteristic database 266. At first, the capacity value is calculated for the size of the initial value 263 and for the second and subsequent times, for the size sent from the size correction unit 268.
[0267]
Next, the determination unit 267 calculates a difference between the capacity value calculated by the capacity value calculation unit 265 and the capacity value to be satisfied by the specification. If the difference is within a predetermined value, it is determined to be OK, the size is output as the size output 269, and the process ends.
[0268]
If the difference is not within the predetermined value, the determination unit 267 determines NO, and the process proceeds to the size correction unit 268. The size correction processing in the size correction unit 268 has already been described with reference to FIGS. 27, 28, and 29. The corrected size value is sent to the capacity value calculation unit 263.
[0269]
As described above, according to the present embodiment, it is possible to automatically determine the size of the capacitor satisfying the content specified in the specification.
[0270]
(Eleventh embodiment)
In the first to ninth embodiments, the processing for automatically determining the size of the resistive element has been described, and in the tenth embodiment, the processing for automatically determining the size of the capacitive element has been described. However, these configurations can also be applied to diode elements by changing some processes.
[0271]
The current value of the diode element is proportional to the area of the PN junction. For convenience, the longitudinal length of the PN junction surface is defined as L, and the lateral length is defined as W. (It may be reversed.) In the sense that the current value is approximately proportional to both L and W, it has the same tendency as the capacitance element described in the tenth embodiment. Therefore, the size of the diode element can be automatically determined with almost the same configuration and processing procedure as in the tenth embodiment shown in FIG.
[0272]
FIG. 32 is a model diagram illustrating a configuration and a processing flow of the device size automatic determination processing unit 285 that automatically determines the size of the diode element. This embodiment differs from the tenth embodiment shown in FIG. 30 in the diode specification 280, the specification input unit 281, the diode characteristic calculation unit 282 in the size examination unit 284, and the diode characteristic database 283. is there.
[0273]
The diode specification 280 has the following seven types. These are input to the specification input unit 281.
[0274]
-Desired current value or voltage value
・ Restrictions on layout
・ Diode terminal voltage condition V (including multiple voltages)
Alternatively, current condition A (including a case of a plurality of voltages)
・ Temperature condition T of diode element
・ Allowable variation amount condition D
-Allowable mismatch amount condition MD
・ Allowable simulation error condition E
If there are no special restrictions on the allowable variation amount condition D, the allowable mismatch amount condition DM, and the allowable simulation error condition E, a predetermined default value is automatically input.
[0275]
The initial value & operation condition determination unit 262 is the same as that in the case of the capacitive element, and similarly outputs the result as the initial value 263 and the operation condition 264.
[0276]
Next, the diode characteristic value calculation unit 282 calculates the diode characteristic value at the designated size under the specified voltage condition and temperature condition in conjunction with the diode characteristic database 283. At first, the diode characteristic value is calculated for the size of the initial value 263 and for the second and subsequent times, for the size sent from the size correction unit 268.
[0277]
The diode characteristic database 283 is used as the device characteristic database. The diode characteristic database 283 stores size-dependent data, voltage-dependent data, temperature-dependent data, size-dependent data of the amount of variation, size-dependent data of the amount of mismatch, and size-dependent simulation error regarding the current value of the diode element. Sex data is stored. FIG. 33 is a schematic diagram showing the data contents of the diode characteristic database 283. For the size-dependent data and the voltage-dependent data, data is stored in the form of a diode current model formula Id (W, L, V). ing. The temperature dependency data is prepared in the form of a table map, and a model formula of size dependency data and voltage dependency data for a plurality of temperature conditions is prepared. That is, although the shapes of the model formulas are equal, the model parameters are changed for each temperature.
[0278]
The diode current model formula is as shown in FIG. 33, in which Is, n, dW, and dL (usually dL = dW) are model parameters. q is the electron charge and k is the Boltzmann constant.
[0279]
Although this model formula is a formula written in a general book on semiconductor properties, other forms may be used.
[0280]
It should be noted that the size dependency data and the voltage dependency data may be a table map format database without using the model formula.
[0281]
The above is the description of the diode characteristic database 283.
[0282]
In FIG. 32, the processing after the diode characteristic value calculation unit 282 is the same as in the ninth embodiment. The size determined by repeating the correction is output as a size output 269.
[0283]
As described above, according to the present embodiment, the size of the diode element that satisfies the contents specified in the specification can be automatically determined.
[0284]
【The invention's effect】
As described above, according to the present invention, in circuit design, the number of design steps for determining a device size based on device information is reduced, design defects are reduced, and the data amount of a device characteristic database is reduced. It is possible to realize an apparatus and method for automatically determining a device size.
[Brief description of the drawings]
FIG. 1 is a model diagram showing a configuration and a processing flow of a resistance element automatic determination processing unit 113 according to a first embodiment of the present invention.
FIG. 2 is a diagram showing a configuration and a processing flow of a layout constraint interpretation unit 103 in FIG. 1;
FIG. 3 is a diagram showing a configuration and a processing flow of a size correcting unit 108 in FIG. 1;
FIG. 4 is a schematic diagram showing a data arrangement in a predetermined size range in the resistance size dependency database 109 of FIG. 1;
FIG. 5 is a schematic diagram for explaining a method of extracting target data by interpolation calculation from the resistance size dependency database 109 of FIG. 1;
FIG. 6 is a diagram showing an example of an interpolation calculation formula when extracting target data from the resistance size dependency database 109 in FIG. 1;
FIG. 7 is a model diagram showing a configuration and a processing flow of a resistance element automatic determination processing unit 145 under a specified voltage condition according to a second embodiment of the present invention.
FIG. 8 is a schematic diagram showing data contents in a resistance size & bias dependence database 143 of FIG. 7;
FIG. 9 is a diagram showing each stage by interpolation when extracting target data from the resistance size & bias dependency database 143 of FIG. 7;
FIG. 10 is a diagram showing a general form of a linear interpolation formula used in FIG. 9;
FIG. 11 is an explanatory diagram of the concept of linear interpolation calculation used in FIG. 9;
FIG. 12 is a model diagram showing a configuration and a processing flow of a resistance element automatic determination processing unit 155 under designated temperature conditions according to a third embodiment of the present invention.
13 is a schematic diagram showing data contents in a resistance size & temperature dependency database 153 of FIG.
FIG. 14 is a model diagram showing a configuration and a processing flow of a resistance element automatic determination processing section 167 under a specified allowable variation amount condition according to a fourth embodiment of the present invention.
FIG. 15 is a schematic diagram showing size dependence data of a variation amount used in the fourth embodiment of the present invention.
FIG. 16 is a schematic diagram for explaining processing for correcting calculation conditions performed by a variation data analysis unit 162 in FIG. 14;
FIG. 17 is a model diagram showing a configuration and a processing flow of a resistance element automatic determination processing unit 175 under a specified allowable mismatch amount condition according to a fifth embodiment of the present invention.
FIG. 18 is a schematic diagram showing size dependence data of a mismatch amount used in the fifth embodiment of the present invention.
FIG. 19 is a model diagram showing a configuration and a processing flow of a resistance element automatic determination processing unit 185 under a specified allowable simulation error condition according to a sixth embodiment of the present invention.
FIG. 20 is a schematic diagram showing size dependence data of a simulation error used in the sixth embodiment of the present invention.
FIG. 21 is a model diagram showing a configuration and a processing flow of a resistance element automatic determination processing unit 196 in which all specifications are simultaneously considered according to a seventh embodiment of the present invention.
FIG. 22 is a schematic diagram for explaining processing performed by an initial value & calculation condition determination unit 192 in FIG. 21;
FIG. 23 is a schematic diagram showing data contents in the resistance characteristic database 194 of FIG. 21;
FIG. 24 is a model diagram showing a configuration and a processing flow of a processing unit for automatically determining an optimum material and a size of a resistance element when there are a plurality of options for a material according to an eighth embodiment of the present invention.
FIG. 25 is a schematic diagram showing data contents in a resistance characteristic database 194 ′ when characteristic data is stored in the form of a model expression according to a ninth embodiment of the present invention.
FIG. 26 is a model diagram showing an internal configuration and a processing flow of a layout constraint interpreting unit 231 in a capacitive element automatic determination processing unit according to a tenth embodiment of the present invention.
FIG. 27 is a model diagram showing an internal configuration and a processing flow of a size correction unit 268 in a capacitance element automatic determination processing unit according to a tenth embodiment of the present invention.
FIG. 28 is a model diagram showing an internal configuration and a processing flow of a W = L calculation unit 236 in the size correction unit 268 of FIG. 27;
FIG. 29 is a model diagram showing an internal configuration and a processing flow of a W ≠ L operation unit 237 in the size correction unit 268 of FIG. 27;
FIG. 30 is a model diagram showing a configuration and a processing flow of an automatic capacitance element size determination processing section 272 according to a tenth embodiment of the present invention.
FIG. 31 is a schematic diagram showing data contents in the capacity characteristic database 266 of FIG. 30;
FIG. 32 is a model diagram showing the configuration and processing flow of an automatic diode element size determination processing unit 285 according to an eleventh embodiment of the present invention.
FIG. 33 is a schematic diagram showing data contents in the diode characteristic database 283 of FIG. 32;
FIG. 34 is a model diagram showing a configuration and a processing flow of a conventional automatic resistance element size determination processing section 310;
FIG. 35 is a diagram showing an example of a resistance element shape.
FIG. 36 is a model diagram showing a configuration of an additional examination processing unit 314 for high-accuracy design.
FIG. 37 is a diagram illustrating a relationship between a line length L of a resistance element and a variation width of a resistance value R;
FIG. 38 is a diagram illustrating a relationship between a line width L of a resistance element and a mismatch width of a resistance value R;
FIG. 39 is a conventional size determination processing flow (manual) for examining a plurality of items for high-accuracy design.
[Explanation of symbols]
101 Resistance specification (design specification)
102 Specification input section (first specification input section)
103 Layout constraint interpreter
104 Initial value
105 Operation conditions
106 Resistance calculator
107 Judgment unit
108 Size correction unit
109 Resistance size dependence database (first device characteristic database)
110 size output
111 Error output
112 Size Examiner (First Size Examiner)
113 Automatic size determination processing unit
120 Restriction-specific branch processing unit
121 area minimum processing unit
122 first initial value
123 First operation condition
124 WL range constraint processing unit
125 Second initial value
126 Second operation condition
127 Unconstrained processing unit
128 Third initial value
129 Third operation condition
130 L size correction unit
131 L size judgment unit
132 Modified size
133 L calculation range end setting unit
134 W size correction unit
135 W size judgment unit
136 W calculation range end setting part
137 Repetition judgment unit
140 Resistance specification (design specification)
141 Specification input section (second specification input section)
142 Resistance calculator
143 Resistance Size & Bias Dependency Database (Second Device Characteristics Database)
144 Size Examiner (Second Size Examiner)
145 Automatic size determination processing unit
150 Resistance specification (design specification)
151 specification input section (third specification input section)
152 Resistance value calculation unit
153 Resistance Size & Temperature Dependency Database (Third Device Characteristics Database)
154 Size Examiner (Third Size Examiner)
155 Automatic size determination processing unit
160 Resistance specification (design specification)
161 Specification input section (fourth specification input section)
162 Variation data analysis unit
163 Modified initial value
164 Correction calculation condition
165 Resistance variation size dependence database (fourth device characteristic database)
166 Size Examiner (4th Size Examiner)
167 Automatic size determination processing unit
170 Resistance specification (design specification)
171 Specification input section (fifth specification input section)
172 Mismatch data analysis unit
173 Resistance mismatch size dependence database (fifth device characteristic database)
174 Size Examiner (Fifth Size Examiner)
175 Automatic size determination processing unit
180 Resistance specification (design specification)
181 Specification input section (sixth specification input section)
182 Simulation error analysis unit
183 Resistance Simulation Error Size Dependency Database (Sixth Device Characteristics Database)
184 size study section (sixth size study section)
185 Automatic size determination processing unit
190 Resistance specification (design specification)
191 Specification input section (seventh specification input section)
192 Initial value & calculation condition determination unit
193 Resistance value calculation unit
194 Resistance characteristic database (seventh device characteristic database)
194 'resistance characteristic database (device characteristic database in the form of model formula)
195 Size Examiner (Seventh Size Examiner)
196 Automatic size determination processing unit
200 Resistance specification (design specification)
201 Specification input section
202 A device automatic size determination processing unit
203 A device database
204 Result output A
205 Automatic size determination processing unit for B device
206 B device database
207 Result output B
208 Comparison Unit
209 size output
210 Error output
221 Branch Processing Unit by Constraint
222 area minimum processing unit
223 first initial value
224 First operation condition
225 WL range constraint processing unit
226 Second initial value
227 Second operation condition
228 Unconstrained processing unit
229 Third initial value
230 Third calculation condition
231 Layout constraint interpreter
232 Initial value obtained from layout constraints
233 Calculation conditions obtained from layout constraints
235 Calculation method branch
236 W = L operation unit
237 W ≠ L operation unit
238 Corrected size
240 size correction unit
241 Size judgment unit
242 Calculation range end setting unit
243 Repetition judgment unit
250 L size correction unit
251 L size judgment unit
252 L calculation range end setting unit
253 W size correction unit
254 W size judgment unit
255 W calculation range end setting unit
256 repetition judgment unit
260 Capacity specification (design specification)
261 Specification input section (seventh specification input section)
262 Initial value & calculation condition determination unit
263 Initial value
264 operation conditions
265 Capacity calculation unit
266 Capacity Characteristics Database (Seventh Device Characteristics Database)
267 Judgment unit
268 Size correction unit
269 size output
270 Error output
271 Size Examiner (Seventh Size Examiner)
272 Automatic size determination processing unit
280 Diode specification (design specification)
281 Specification input section (seventh specification input section)
282 Diode characteristic value calculator
283 Diode Characteristics Database (Seventh Device Characteristics Database)
284 Size Examiner (Seventh Size Examiner)
285 Automatic size determination processing unit
301 Resistance Value Examiner
302 Design Device Specification
303 Specification input section
304 Sheet Number Examiner
305 First device information section
306 seat specification
307 Size Examination Department
308 Design Rule Department
309 size output
310 Conventional size automatic determination processing unit
311 Additional Data Examiner
312 Second device information section
313 Output modified size
314 Additional examination processing unit
315 First Stage Review
316 Second Stage Review
317 Third Stage Review
318 Final Stage Review
319 Corrected size

Claims (18)

A first specification input unit for inputting design specifications relating to desired device characteristic values and layout constraints of a device constituting the semiconductor integrated circuit;
A first device characteristic database that stores size dependence data of device characteristic values under a predetermined temperature condition, a predetermined voltage condition, or a predetermined current condition;
Upon receiving the design specification output from the first specification input unit, referring to the first device characteristic database, while examining device characteristic values for each device size, determining a device size satisfying the design specification An apparatus for automatically determining a device size, comprising: a first size study unit for studying and determining. Design specifications relating to an arbitrary voltage condition in a predetermined voltage range or an arbitrary current condition in a predetermined current range, a desired device characteristic value under the condition, and a layout constraint of a device constituting the semiconductor integrated circuit are input. A second specification input unit to be executed;
A second device characteristic database storing size dependence data and voltage dependence data of device characteristic values under predetermined temperature conditions, or size dependence data and current dependence data,
In response to the design specification output from the second specification input unit, while referring to the second device characteristic database, while examining device characteristic values for each device size under the arbitrary voltage condition or current condition, And a second size examination unit for examining and determining a device size that satisfies the input design specification. A third specification input unit for inputting an arbitrary temperature condition in a predetermined temperature range of the device constituting the semiconductor integrated circuit, a desired device characteristic value under the temperature condition, and a design specification regarding a layout constraint; ,
A third device characteristic database storing size dependence data and temperature dependence data of device characteristic values under a predetermined voltage condition or a predetermined current condition;
In response to the design specification output from the third specification input unit, by referring to the third device characteristic database, while checking the device characteristic value for each device size under the predetermined temperature condition, the input is performed. An automatic device size determination device, comprising: a third size study unit for studying and determining a device size satisfying the design specification. A fourth specification input unit for inputting a desired device characteristic value of a device constituting the semiconductor integrated circuit, an allowable variation amount condition of the device characteristic value, and a design specification relating to a layout constraint;
A first device characteristic database that stores size dependence data of device characteristic values under a predetermined temperature condition, a predetermined voltage condition, or a predetermined current condition;
A fourth device characteristic database storing size dependence data of the variation amount of the device characteristic value under a predetermined temperature condition, a predetermined voltage condition, or a predetermined current condition;
Upon receiving the design specification output from the fourth specification input unit, based on the allowable variation amount condition and the size dependency data of the variation amount stored in the fourth device characteristic database. Setting an area of a designable size, referring to the first device characteristic database, and examining a device characteristic value for each device size; An automatic device size determination device, comprising: a fourth size examination unit that examines and decides a device size satisfying specifications. A fifth specification input unit for inputting a desired device characteristic value of a device constituting the semiconductor integrated circuit, an allowable mismatch amount condition of the device characteristic value, and design specifications related to layout restrictions;
A first device characteristic database that stores size dependence data of device characteristic values under a predetermined temperature condition, a predetermined voltage condition, or a predetermined current condition;
A fifth device characteristic database storing size dependence data of a mismatch amount of a device characteristic value under a predetermined temperature condition, a predetermined voltage condition, or a predetermined current condition;
Upon receiving the design specification output from the fifth specification input unit, based on the allowable mismatch amount condition and the size dependence data of the mismatch amount stored in the fifth device characteristic database. Setting an area of a designable size, referring to the first device characteristic database, and examining a device characteristic value for each device size; An automatic device size determination device, comprising: a fifth size examination unit that examines and decides a device size satisfying specifications. A sixth specification input unit for inputting a desired device characteristic value of a device constituting the semiconductor integrated circuit, an allowable simulation error condition of the device characteristic value, and a design specification regarding a layout constraint;
A first device characteristic database that stores size dependence data of device characteristic values under a predetermined temperature condition, a predetermined voltage condition, or a predetermined current condition;
A sixth device characteristic database that stores size dependence data of a simulation error of a device characteristic value under a predetermined temperature condition, a predetermined voltage condition, or a predetermined current condition;
Upon receiving the design specification output from the sixth specification input unit, based on the allowable simulation error condition and the size dependence data of the simulation error stored in the sixth device characteristic database. Setting an area of a designable size, referring to the first device characteristic database, and examining a device characteristic value for each device size; An automatic device size determination device, comprising: a sixth size examination unit that examines and decides a device size satisfying specifications. Arbitrary voltage conditions in a predetermined voltage range or arbitrary current conditions in a predetermined current range, arbitrary temperature conditions in a predetermined temperature range, allowable variation amount conditions of device characteristic values, device characteristics of devices constituting a semiconductor integrated circuit A seventh specification input unit for inputting at least one selected from an allowable mismatch amount condition of a value and an allowable simulation error condition of a device characteristic value, a desired device characteristic value, and a design specification relating to a layout constraint; When,
Any voltage condition in the predetermined voltage range or any current condition in the predetermined current range, any temperature condition in the predetermined temperature range, the allowable variation amount condition, the allowable mismatch amount condition, and the allowable simulation error Voltage-dependent data or current-dependent data of a device characteristic value under a predetermined temperature condition, temperature-dependent data of a device characteristic value under a predetermined voltage condition or a predetermined current condition, respectively corresponding to a condition selected from the conditions. And size dependency data of a variation amount, size dependency data of a mismatch amount, and size dependency data of a simulation error of a device characteristic value under a predetermined temperature condition, a predetermined voltage condition, or a predetermined current condition. At predetermined temperature and voltage conditions There is a seventh device characteristic database size dependence data of the device characteristic values are stored in a predetermined current condition,
Upon receiving the design specification output from the seventh specification input unit, at least one condition selected from the allowable variation amount condition, the allowable mismatch amount condition, and the allowable simulation error condition is input. In the case, the input condition and the device characteristic value stored in the seventh device characteristic database corresponding to the condition, the size dependence data of the variation amount, the size dependence data of the mismatch amount, And setting a region of a designable size based on the size dependence data of the simulation error and referring to the seventh device characteristic database to investigate a device characteristic value for each device size. Consider and determine the device size that satisfies the input design specifications from within the possible size area. Automatic determination device of device size, characterized in that a size considered part of the seventh. In the device characteristic database, data corresponding to each material of the same type of device made of a plurality of different materials is stored, the size study unit determines a plurality of device sizes corresponding to the different materials, 8. The automatic device size determining apparatus according to claim 1, wherein a plurality of device sizes are respectively compared to determine an optimum material satisfying the design specification. 9. The device according to claim 1, wherein the device characteristic database stores data in the form of a model expression that approximates the device characteristic value. Inputting design specifications relating to desired device characteristic values and layout constraints of the devices constituting the semiconductor integrated circuit;
Setting an initial value of a device size according to the input layout constraint;
Extracting a device characteristic value at the set initial size value from a first device characteristic database storing size dependence data of the device characteristic value under a predetermined temperature condition, a predetermined voltage condition, or a predetermined current condition. When,
Determining whether the extracted device characteristic value satisfies the input design specification,
If the result of the determination is that the design specification is not satisfied, then repeating the size correction in accordance with the set size correction rule, automatically calculating and outputting the device size, and outputting the device size. . Input of arbitrary voltage conditions in a predetermined voltage range or arbitrary current conditions in a predetermined current range, desired device characteristic values under the conditions, and design specifications relating to layout constraints of devices constituting the semiconductor integrated circuit. Steps to
Setting an initial value of a device size according to the input layout constraint;
A second device in which the device characteristic value at the set size initial value is stored as size dependence data and voltage dependence data, or size dependence data and current dependence data of the device characteristic value under a predetermined temperature condition. Extracting from a characteristic database;
Determining whether the extracted device characteristic value satisfies the input design specification,
If the result of the determination is that the design specification is not satisfied, then repeating the size correction in accordance with the set size correction rule, automatically calculating and outputting the device size, and outputting the device size. . Inputting a design specification relating to an arbitrary temperature condition in a predetermined temperature range of the device constituting the semiconductor integrated circuit, a desired device characteristic value under the temperature condition, and a layout constraint;
Setting an initial value of a device size according to the input layout constraint;
Extracting a device characteristic value at the set initial size value from a third device characteristic database storing size dependence data and temperature dependence data of the device characteristic value under a predetermined voltage condition or a predetermined current condition. When,
Determining whether the extracted device characteristic value satisfies the input design specification,
If the result of the determination is that the design specification is not satisfied, the method further comprises the steps of repeating size correction according to the set size correction rule, automatically calculating and outputting the device size, and outputting the device size. Inputting a design specification relating to a desired device characteristic value, a permissible variation amount condition of the device characteristic value, and a layout constraint of a device constituting the semiconductor integrated circuit;
Setting a designable size area based on the input allowable variation amount condition and the size dependence data of the variation amount of the device characteristic value stored in the fourth device characteristic database;
Setting an initial value of a device size according to the input constraints on the layout, from within the area of the set designable size;
Extracting a device characteristic value at the set initial size value from a first device characteristic database storing size dependence data of the device characteristic value under a predetermined temperature condition, a predetermined voltage condition, or a predetermined current condition. When,
Determining whether the extracted device characteristic value satisfies the input design specification,
If the result of the determination is that the design specification is not satisfied, the step of repeating the size correction from within the designable size area according to the set size correction rule, automatically calculating and outputting the device size is included. A method for automatically determining the featured device size. Inputting a design specification relating to a desired device characteristic value of the device constituting the semiconductor integrated circuit, an allowable mismatch amount condition of the device characteristic value, and a layout constraint;
Setting an area of a designable size based on the input allowable mismatch amount condition and the size dependence data of the mismatch amount of the device characteristic value stored in the fifth device characteristic database;
Setting an initial value of a device size according to the input constraints on the layout, from within the area of the set designable size;
Extracting a device characteristic value at the set initial size value from a first device characteristic database storing size dependence data of the device characteristic value under a predetermined temperature condition, a predetermined voltage condition, or a predetermined current condition. When,
Determining whether the extracted device characteristic value satisfies the input design specification,
If the result of the determination is that the design specification is not satisfied, the step of repeating the size correction from within the designable size area according to the set size correction rule, automatically calculating and outputting the device size is included. A method for automatically determining the featured device size. Inputting a design specification relating to a desired device characteristic value, an allowable simulation error condition of the device characteristic value, and a layout constraint of a device configuring the semiconductor integrated circuit;
Setting an area of a designable size based on the input allowable simulation error condition and the size dependence data of the simulation error of the device characteristic value stored in the sixth device characteristic database;
Setting an initial value of a device size according to the input constraints on the layout, from within the area of the set designable size;
Extracting a device characteristic value at the set initial size value from a first device characteristic database storing size dependence data of the device characteristic value under a predetermined temperature condition, a predetermined voltage condition, or a predetermined current condition. When,
Determining whether the extracted device characteristic value satisfies the input design specification,
If the result of the determination is that the design specification is not satisfied, the step of repeating the size correction from within the designable size area according to the set size correction rule, automatically calculating and outputting the device size is included. A method for automatically determining the featured device size. Arbitrary voltage conditions in a predetermined voltage range or arbitrary current conditions in a predetermined current range, arbitrary temperature conditions in a predetermined temperature range, allowable variation amount conditions of device characteristic values, device characteristics of devices constituting a semiconductor integrated circuit Inputting at least one selected from an allowable mismatch amount condition of a value and an allowable simulation error condition of a device characteristic value, a desired device characteristic value, and design specifications related to layout constraints;
When at least one condition selected from the allowable variation amount condition, the allowable mismatch amount condition, and the allowable simulation error condition is input as the design specification, the input condition corresponds to the input condition. Design based on the size dependence data of the variation amount, the size dependence data of the mismatch amount, and the size dependence data of the simulation error of the device characteristic values stored in the seventh device characteristic database. Setting an area of an appropriate size;
Setting an initial value of a device size according to the input constraints on the layout, from within the area of the set designable size;
A device characteristic value at the set initial size value is extracted from the seventh device characteristic database storing size dependence data of the device characteristic value under a predetermined temperature condition, a predetermined voltage condition, or a predetermined current condition. Steps and
Determining whether the extracted device characteristic value satisfies the input design specification,
If the result of the determination is that the design specification is not satisfied, the step of repeating the size correction from within the designable size area according to the set size correction rule, automatically calculating and outputting the device size is included. A method for automatically determining the featured device size. In the device characteristic database, data corresponding to each material of the same type of device composed of a plurality of different materials is stored,
The method for automatically determining the device size further includes:
Determining a plurality of device sizes corresponding to the different materials;
17. A method for automatically determining a device size according to claim 10, further comprising: comparing each of the plurality of device sizes to determine an optimum material satisfying the design specification. The method according to any one of claims 10 to 17, wherein the device characteristic database stores data in the form of a model expression that approximates the device characteristic value.

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