JP2004227190A - Device size determination device and device size determination method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a device size determination device and method capable of reducing design man-hour and design defects when performing a device size determination based on device information by properly correcting a design specification in a circuit design. <P>SOLUTION: When determination of a device size satisfying the specification 101 fails in an automatic size-determination processing part 102, the content of the specification 101 is analyzed in a specification analysis part 108, and a corrected specification plan 110 is determined in a corrected specification plan determination part 109 on the basis of the analytic result. The device size is re-determined based thereon by the automatic size-determination processing part 102. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention corrects the design specifications that hinder the automatic sizing of the devices constituting the semiconductor integrated circuit, particularly the diode elements, the resistive elements, and the capacitive elements so that the automatic sizing can be performed. The present invention relates to a technique for reducing 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 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 emitter is used for the same purpose as a diode is used. 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, software for automatically creating a mask layout of a semiconductor circuit having this function has been conventionally available.
[0006]
FIG. 17 shows a configuration example of a processing unit and a processing flow when a resistance of 1000Ω is designed by the mask layout automatic creation software.
[0007]
In FIG. 17, 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 are shapes such as a linear type and a bent type as shown in FIG. Further, 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 as in 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. 17 is a part related to the processing of the conventional mask layout automatic creation software.
[0012]
[Patent Document 1]
Japanese Patent Publication No. 6-23988
[0013]
[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.
[0014]
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.
[0015]
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.
[0016]
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.
[0017]
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).
[0018]
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.
[0019]
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.
[0020]
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. 17, an additional examination processing unit 314 as shown in FIG. 19 is required. This is in the form of equation (2) above.
[0021]
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).
[0022]
The conventional additional examination processing 314 surrounded by a dotted line in FIG. 19 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.
[0023]
In addition, there are many other items that require additional examination in order to determine the device size with high accuracy. For example, the size dependence, voltage dependence, current dependence, temperature dependence, characteristic variation, characteristic mismatch, or simulation error of device characteristics must be defined and examined as device information or device characteristics in a broad sense. Must. Therefore, an extremely large number of design steps are required to determine the device size. Further, for example, there is a possibility that a designer may pay attention only to optimizing a specific condition and cause a design failure.
[0024]
An object of the present invention is to provide a device size determination apparatus that can reduce design man-hours when determining a device size based on device information and reduce design defects by appropriately modifying design specifications in circuit design. And a method.
[0025]
[Means for Solving the Problems]
In order to achieve the above object, a device size determination device according to the present invention is a device size determination device that inputs design specifications of devices constituting a semiconductor integrated circuit and determines a device size according to the input specifications. A device characteristic storage unit that stores a device characteristic value for each device size, a size determination unit that refers to the device characteristic value in the device characteristic storage unit, and determines a device size according to an input design specification; A specification change unit that changes a design specification when the device size cannot be determined or the determination result is inappropriate, wherein the size determination unit changes the device size according to the design specification changed by the specification change unit. Is determined again.
[0026]
In this configuration, if the size cannot be determined because there is no device size that satisfies all of the design specifications, or if the determination result is inappropriate, change the design specification and re-install the device according to the changed design specification. Determine the size. As a result, the device size can be automatically determined while automatically correcting the specification, and the number of design steps can be reduced.
[0027]
As the design specification, a size constraint condition on a layout, an allowable variation condition, an allowable mismatch condition, and an allowable simulation error condition can be used.
[0028]
Then, when it is impossible to determine the device size because there is no device size region that simultaneously satisfies all of the conditions input as the design specifications, the specification change unit sets each of the conditions in the device size region to It is preferable to examine the positional relationship of the region to be satisfied and select and change any of the conditions from the obtained positional relationship information so that there is a size region that simultaneously satisfies all of the above conditions.
[0029]
Further, the specification change unit checks whether or not an abnormal specification has been input according to a predetermined rule.If an abnormal specification exists, a size region that simultaneously satisfies all the conditions input as the design specification is present. It is preferable to correct the abnormal specification.
[0030]
This configuration has a function of preferentially changing an abnormal specification when an abnormal or unrealistic specification is input due to, for example, an input error or a lack of skill of a designer. Thereby, even if there is an abnormal specification, the specification can be changed in a desirable manner.
[0031]
Further, when there is an area having a device size that simultaneously satisfies all of the conditions input as the design specifications, but it is not possible to determine the device size, the specification change unit may change the condition according to a predetermined rule. Preferably, by changing any of the selected conditions, the size region satisfying all of the above conditions at the same time is enlarged.
[0032]
Further, when it is impossible to determine the device size even though there is a device size region that simultaneously satisfies all of the conditions input as the design specifications, the specification change unit outputs the predetermined voltage regardless of the condition. A size region that satisfies only the device characteristic condition under the condition and the temperature condition or only the device characteristic condition under the predetermined current condition and the temperature condition is obtained, and this region overlaps with the region that simultaneously satisfies all the conditions input as the design specifications. By changing any of the conditions selected from the conditions input as the design specifications in accordance with a predetermined rule, it is possible to expand a size region that simultaneously satisfies all the conditions input as the design specifications. preferable.
[0033]
This configuration has a function of obtaining a size area that satisfies only the other specifications without using these four conditions when there is an area that satisfies all four conditions input as design specifications. That is, a region that satisfies the device characteristic value, the voltage condition, and the temperature condition is obtained. Then, the specifications of the four conditions input as the design specifications are changed so that there is an area where all these areas overlap. According to this, it is possible to cope with a case where the size cannot be determined in spite of the existence of the fifth region, and the number of design steps can be reduced.
[0034]
In each of the above-described configurations, it is preferable that the contents of the specification change by the specification change unit are confirmed, and when the change contents are not satisfied, the specification change unit changes the specification again. Thus, the operator can finally confirm whether the specification modification plan is satisfactory. If there is any dissatisfaction, the specification can be changed again before returning to the automatic size determination processing. Therefore, it is possible to prevent specification changes that do not suit the designer's intention.
[0035]
Further, in each of the above-described configurations, information for designating the priority of the specification change, prohibition of the change, a range in which the change is allowed, or information for directly instructing the specification change is input to the specification change unit. It is preferable to further include a condition specifying unit. Further, it is more preferable that the display device further includes a display unit for displaying a positional relationship of the specification condition changed according to the information in accordance with the input of the information from the condition designating unit and a positional relationship of the upper and lower limits of the allowable change range. This makes it possible to directly understand the effect of the specification change, especially when the specification is manually changed, thereby reducing the number of design steps.
[0036]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.
[0037]
(First embodiment)
A first embodiment of the present invention will be described.
[0038]
As shown in FIG. 1, the device size determining apparatus according to the present embodiment includes a size determining unit 111, a device characteristic database 105, and a specification change processing unit 112. When a design specification 101 such as a resistance element, a capacitance element, or a diode element is input, the size determination unit 111 refers to the device characteristic database 105 and performs a process of automatically determining an optimal size satisfying the specification. If the automatic size determination fails, the specification change processing unit 112 changes the specification, and then the size determination unit 111 performs the automatic size determination process again.
[0039]
As the design specification 101, for example, a resistance value is used when the device is a resistance element, and a capacitance value is used when the device is a capacitance element. In the case of a diode element, a current value under a certain voltage condition or a voltage value under a certain current condition is input as the design specification 101. Further, in addition to this, a size constraint condition on a layout, a voltage or current condition, a temperature condition, an allowable variation condition, an allowable mismatch condition, an allowable simulation error condition, and the like may be input.
[0040]
Here, the contents of the automatic size determination processing in the size determination unit 111 will be described. The size determination unit 111 includes an automatic size determination processing unit 102 and a correctness determination unit 103.
[0041]
The automatic size determination processing unit 102 determines a device size that satisfies the input specifications in cooperation with the device characteristic database 105.
[0042]
As described above, specifying the allowable variation condition, the allowable mismatch condition, and the allowable simulation error condition indirectly specifies the size condition that allows layout. Therefore, the size constraint condition, the allowable variation condition, the allowable mismatch condition, and the allowable simulation error condition on the layout are referred to as four size-related conditions.
[0043]
An area determined by the size constraint on the layout is referred to as a first area. Here, the “region” refers to a region in the coordinate space representing the device size, which is composed of a set of device sizes satisfying the condition. An area determined from the permissible variation condition is defined as a second area. An area determined by the allowable mismatch condition is defined as a third area. An area determined from the allowable simulation error condition is defined as a fourth area. The four regions defined as described above have a common definition in this specification.
[0044]
FIG. 2 shows first to fourth areas determined from the four size-related conditions. A common area in which the first area A1, the second area A2, the third area A3, and the fourth area A4 all overlap is defined as a fifth area (A5). The automatic size determination processing unit 102 determines, from within the fifth area A5, a size that satisfies specifications other than the four size-related conditions.
[0045]
If the device size is actually determined (success), the success / failure determination unit 103 outputs the result as the result output 104. If the size cannot be determined (failure), the fact is notified to the specification change processing unit 112, and the specification change processing unit 112 creates a modified specification plan as described later. Then, based on the modified specification, the size determination unit 111 performs the automatic size determination process again.
[0046]
For example, as shown in FIG. 3, when there is no fifth region where all of the first region B1, the second region B2, the third region B3, and the fourth region B4 overlap, the size cannot be determined. The change processing unit 112 corrects the specification plan.
[0047]
Here, the processing contents of the specification change processing unit 112 will be described.
[0048]
First, the specification analyzing unit 108 converts the four size-related conditions in the specification 101 into the first to fourth areas of the size conditions using the device characteristic database 105, and obtains position information thereof.
[0049]
Next, based on the position information of the first to fourth areas, the modified specification proposal determining unit 109 analyzes which specification should be changed by how much to have the fifth area, and create. The modified specification plan 110 is returned to the automatic size determination processing unit 102 in the size determination unit 111. In this case, the information is linked with the device characteristic database 105. That is, the device characteristic database 105 stores information on what the first to fourth areas will be based on the specification conditions. During the analysis of the specification change, the device characteristic database 105 sequentially reads the first to fourth regions. To the fourth region.
[0050]
The function of the specification analysis unit 108 is also provided in the automatic size determination processing unit 102, and the specification change processing unit 112 is not provided with the specification analysis unit 108. It may be possible to adopt a configuration in which information is directly extracted from the server.
[0051]
The processing content of the modified specification plan determination unit 109 will be described in more detail with reference to FIG.
[0052]
The modified specification plan determination unit 109 receives the specification analysis result from the specification analysis unit 108, and the state determination unit 120 classifies the state in which the fifth area does not exist into two types. Branching occurs when there is a portion where three types of regions overlap among the first to fourth regions and when there is no portion where three types of regions overlap.
[0053]
If there is a portion where the three types of regions overlap, the process proceeds to the specification adjustment unit 121. If there is no portion where the three types of regions overlap, the process proceeds to the default comparison unit 123.
[0054]
The specification adjustment unit 121 determines that the remaining one condition that does not overlap the portion where the three types of regions overlap is the bottleneck. The specification of the constituent element of the bottleneck region is changed by a predetermined amount to enlarge the region.
[0055]
For example, as shown in FIG. 3, when there is a portion where the second region B2, the third region B3, and the fourth region B4 overlap, the first region B1 is enlarged to have a fifth region.
[0056]
Next, the area determining unit 122 analyzes the positional relationship between the first to fourth areas again in the changed specification, and determines whether the fifth area is present.
[0057]
If there is a fifth area, the result of the specification change performed by the specification adjustment unit 121 is output as the modified specification plan 110.
[0058]
If there is no fifth region, the specification adjusting unit 121 again changes the specification that is the bottleneck by a predetermined amount. Until the fifth area is present, the processing of the specification adjustment unit 121 and the processing of the area determination unit 122 are repeated.
[0059]
On the other hand, when the state determination unit 120 determines that there is no portion where the three types of regions overlap among the first region C1, the second region C2, the third region C3, and the fourth region C4 as shown in FIG. Since the second region and the third region always have a region overlapping at the upper right, such a case may occur because the common portion of the second region and the third region is too close to the upper right, or the first region And whether the fourth area is past the lower left. Further, when an unrealistic specification is input, there may be a case where the region itself does not exist.
[0060]
In the present embodiment, the specification comparing unit 123 detects a specification that largely deviates from the default specification. As the default specification, a specification which is usually a well-specified value and has a fifth area as shown in FIG. 2 is used.
[0061]
In comparison with the default specification, the specification that is the most deviated from the default is set as a change target. If there are a plurality of specifications that deviate the most, all of them are changed.
[0062]
Then, the abnormal specification change unit 124 changes the specification to be changed by a predetermined amount.
[0063]
Next, the area discriminating unit 125 analyzes the positional relationship between the first to fourth areas again in the changed specification, and determines whether the fifth area is present or a part where three types of areas are overlapped. It is determined whether or not it has become.
[0064]
If there is a fifth area, the result of the specification change performed by the abnormal specification change unit 124 is output as the modified specification plan 110.
[0065]
Even when the fifth area does not exist, if there is a portion where three types of areas overlap, the process proceeds to the specification adjusting unit 121 instead of the default comparing unit 123.
[0066]
If the fifth region does not exist and there is no portion where the three types of regions overlap, the default comparing unit 123 is again caused to execute the above-described processing.
[0067]
The specification change plan 110 output from the modified specification plan determination unit 109 as described above is configured to be sent to the automatic size determination processing unit 102 instead of the specification 101 as shown in FIG.
[0068]
As described above, according to the present embodiment, even when the first input specification 101 does not have the fifth area, the specification is automatically corrected so that the fifth area exists, thereby saving a lot of design man-hours. Automatic size determination can be performed without the need.
[0069]
In the present embodiment, the success / failure determination unit 103 determines success / failure based on whether or not the fifth region exists. However, the criterion of success / failure of the automatic size determination process is not limited to this. . For example, even when the fifth area exists, even when an inappropriate result is obtained, for example, only an unrealistic device size is determined, the processing is shifted to the specification change processing unit 112. May be.
[0070]
(Second embodiment)
A second embodiment of the present invention will be described below.
[0071]
FIG. 6 is an explanatory diagram of a specification change processing unit included in the automatic device size determination device according to the second embodiment.
[0072]
For example, if one or more of the four size-related conditions specifies an unrealistic specification due to a designer error or lack of skills, the unrealistic specification should be corrected without correction. May change the non-optimal specifications, resulting in a suboptimal size. As shown in FIG. 7, when the third area G3 is extremely closed to the upper right, the specifications are changed so that the first area G1 and the second area G2 are shown as areas G1 ′ and G2 ′ in FIG. If this is done, the fifth region G5 does exist, but a very large size is determined. Therefore, if it is desired to design the device as small as possible, it will not be possible to exert sufficient ability.
[0073]
Therefore, as shown in FIG. 6, in the present embodiment, the specification change processing unit 132 provided in place of the specification change processing unit 112 in FIG. 1 corrects the specification in response to the input of an abnormal specification. Do. Specifically, an abnormal specification determining unit 130 and an abnormal specification correcting unit 131 are added before the specification analyzing unit 108.
[0074]
The abnormal specification determining unit 130 sets, for each specification, an upper limit that is not expected to exceed in a normal device specification unless there is a very good situation, and a lower limit that is unlikely to be lower. Then, it is determined whether the specification actually input is within the range of the upper and lower limits or out of the range. If it is within the range, the process shifts to the specification analysis unit 108; otherwise, the process shifts to the abnormal specification correction unit 131.
[0075]
The abnormal specification correction unit 131 changes the specification exceeding the upper limit to the upper limit. Also, the specification below the lower limit is changed to the lower limit. Then, the processing shifts to the specification analysis unit 108.
[0076]
As described above, according to the present embodiment, even if the fifth area does not exist due to the fact that the initially input specification 101 includes an abnormal value, the abnormal specification is corrected first with priority. When the fifth region exists and the automatic specification is corrected in a desired direction, the size can be automatically determined.
[0077]
(Third embodiment)
A third embodiment of the present invention will be described below.
[0078]
Although the fifth region exists, the specifications other than the size-related four conditions cannot be satisfied in the fifth region, and the size cannot be automatically determined in some cases. The device size automatic determination device according to the third embodiment corrects the specification in response to such a case.
[0079]
For this reason, as shown in FIG. 9, in the present embodiment, a state determination unit 135 is added between the specification analysis unit 108 and the modified specification plan determination unit 109, and after this state determination unit 135, a modified specification plan determination This is a configuration in which a fifth area adjustment unit 136 is added in parallel with the unit 109.
[0080]
Although not shown in FIG. 9, the configuration may be such that the abnormal specification determining unit 130 and the abnormal specification correcting unit 131 described in the second embodiment are further added.
[0081]
The state determination unit 135 determines whether or not the fifth area exists based on the information obtained from the specification analysis unit 108.
[0082]
If there is no fifth area, the process proceeds to the modified specification plan determination unit 109 as described in the first embodiment.
[0083]
On the other hand, if there is a fifth area, the process proceeds to the fifth area adjustment unit 136.
[0084]
The fifth area adjustment unit 136 performs specification correction so that the fifth area is enlarged, and outputs the result as a corrected specification proposal 110.
[0085]
When a region that satisfies specifications other than the size-related four conditions, for example, a device characteristic value, a voltage or current condition, and a temperature condition is a sixth region, the sixth region D6 and the fifth region D5 overlap as shown in FIG. If the seventh region D7, which is a part, exists, the size is determined from the seventh region D7. However, if there is no seventh region where the fifth region E5 and the sixth region E6 overlap as shown in FIG. 11, the size cannot be determined.
[0086]
The fifth area adjustment unit 136 changes the four size-related conditions from the state of FIG. 11 to the state of FIG.
[0087]
The flow of the process of the fifth area adjustment unit 136 will be described with reference to FIG. In the first half of the fifth area adjustment unit 136, the sixth area is obtained, and in the second half, the specification is corrected so that the seventh area exists.
[0088]
Before describing the specific processing, the layout size of the device is defined by W and L sizes.
[0089]
If the device is a resistor, the resistance line width is W and the resistance line length is L. In the case of a capacity, the length of the parallel plate portion is W and the width is L. In the diode, the length of the PN junction plane is W and the width is L.
[0090]
In the sixth area analysis specification creation 140, the following sixth area analysis specification 141 is created.
[0091]
(1) Device characteristic value: Same as specification 101
(2) Layout restrictions: W is the minimum design rule
(3) Voltage or current conditions: Same as specification 101
(4) Temperature condition: Same as specification 101
(5) Permissible variation condition: condition in which the second area is maximized
(6) Allowable mismatch condition: condition that maximizes the third area
(7) Allowable simulation error condition: condition where the fourth area is maximum
FIG. 13 shows the upper and lower limits of the design rule. The upper limit of W is Wmax, the lower limit of W is Wmin, the upper limit of L is Lmax, and the lower limit of L is Lmin. However, when there is no upper limit in the design rule, values based on the chip size are Wmax and Lmax. The second to fourth areas are set so as to cover the entire area shown in FIG.
[0092]
The device size is determined by using the function of the automatic size determination processing 102 using the sixth area analysis specification 141. At this time, since W is already determined by the specification, L is obtained. The resulting combination of W and L becomes part of the sixth region.
[0093]
Next, in the end determination 142, if the obtained combination of W and L is inside the area shown in FIG. 13, the process proceeds to the W increase 143 to continue the analysis of the sixth area.
[0094]
In the W increase 143, a new sixth area analysis specification 141 in which W is increased by a predetermined amount is created. Other specifications will be continued. Then, L in the new W is obtained.
[0095]
On the other hand, in the end determination 142, when the position is outside the region shown in FIG.
[0096]
In the position comparison 145, the positional relationship between the obtained area sixth area and the already obtained fifth area is checked, and the process proceeds to the specification change 146.
[0097]
In the specification change 146, four size-related conditions are changed based on positional relationship information between the sixth area and the fifth area.
[0098]
Specifically, when the sixth area is at the upper left of the fifth area as shown in FIG. 11, the specification of the third area that determines the left limit of the fifth area is changed by a predetermined amount, and By changing the specifications of the first area, which determines the upper limit of the five areas, by a predetermined amount, the fifth area is enlarged in the upper left direction.
[0099]
Other cases where the positional relationship is other will be described.
[0100]
When the sixth area is at the upper right of the fifth area, the specification that determines the right limit of the fifth area is changed by a predetermined amount, and the specification that determines the upper limit of the fifth area is changed by a predetermined amount. By changing, the fifth region is enlarged in the upper right direction.
[0101]
When the sixth area is at the lower right of the fifth area, the specification that determines the right limit of the fifth area is changed by a predetermined amount, and the specification that determines the lower limit of the fifth area is changed by a predetermined amount. The fifth area is enlarged in the lower right direction by only changing
[0102]
When the sixth area is at the lower left of the fifth area, the specification that determines the left limit of the fifth area is changed by a predetermined amount, and the specification that determines the lower limit of the fifth area is changed by a predetermined amount. By changing, the fifth region is enlarged in the lower left direction.
[0103]
After the specification has been changed by a predetermined amount, the process proceeds to the seventh area presence / absence determination 147, and it is checked whether the seventh area is present. If there is no seventh region, the process returns to the specification change 146 again to continue the specification change.
[0104]
On the other hand, when the seventh area is present, the specification change is terminated, and the modified specification proposal 110 is output.
[0105]
In the present embodiment, when the sixth area is obtained, W is gradually increased from the minimum size of W, and the method of obtaining L at each time is used. Alternatively, the method may be changed to a method of obtaining L at each time.
[0106]
In the present embodiment, the method of obtaining L at each time by changing W when obtaining the sixth area is described. However, the method of obtaining W at each time by changing L may be used. No problem.
[0107]
As described above, according to the present embodiment, even if the size cannot be determined even if the fifth area is provided, the automatic specification correction is performed so that the seventh area exists, thereby automatically determining the size. become able to.
[0108]
(Fourth embodiment)
A fourth embodiment of the present invention will be described below.
[0109]
When the specification is changed automatically, there is a possibility that the change cannot be permitted depending on the convenience of the designer.
[0110]
Therefore, the automatic device size determination device according to the present embodiment can prevent unnecessary rework by adding a function for the designer to confirm the specification change contents to the first to third embodiments, A function for setting the condition of the correction method has been added, and the specification can be corrected more in accordance with the designer's idea.
[0111]
FIG. 14 illustrates a part of the automatic device size determination apparatus according to the present embodiment that is different from the first embodiment.
[0112]
In the present embodiment, as shown in FIG. 14, a specification change processing unit 155 obtained by partially changing the specification change processing unit 112 shown in FIG. 1 is used. In the specification change processing unit 155, after the processing by the specification analysis unit 108, the correction method branching unit 150 determines whether the specification is automatically corrected or the designer sets conditions. If the specification is to be automatically corrected, the process proceeds to the corrected specification plan determination unit 151. The modified specification plan determining unit 151 corresponds to the modified specification plan determining unit 109 or the modified specification plan determining unit 137 described in the other embodiments.
[0113]
On the other hand, when the specification of the specification change is performed, the process proceeds to the correction condition specification unit 152. Here, the correction condition 153 is input by the designer. As the contents of the correction condition 153, for example, setting of a change target priority, setting of a change prohibition item, and setting of a changeable range are performed. It is also possible for the designer to directly input the details of the change.
[0114]
After the setting of the correction condition, the processing is shifted to the correction specification plan determination unit 151.
[0115]
The modified specification plan determination unit 151 modifies the specification according to the modification conditions as follows.
(1) When priority order is set
The specifications are modified in order of priority. However, if the limit is exceeded, the specification of the next rank will be changed.
[0116]
(2) When change prohibition is set
Specifications that are prohibited from being changed are not changed at all.
[0117]
(3) When the changeable range is set
When the upper and lower limits of the changeable range are reached, no further changes will be made and other specifications will be changed.
[0118]
When the proposed modification specification is determined, the designer confirms in a confirmation 154 whether or not the proposed modification is acceptable. If it is good, the modified specification plan 110 is determined.
[0119]
As described above, according to the present embodiment, by providing the size correction condition, the specification can be corrected within the allowable range of the designer, and the size can be automatically determined.
[0120]
(Fifth embodiment)
A fifth embodiment of the present invention will be described.
[0121]
When the specification is changed manually as in the fourth embodiment, it is difficult to directly understand the effect of the change on the automatic size determination. For this reason, there is a possibility that redo may occur many times.
[0122]
Therefore, the present embodiment is obtained by adding a function of displaying the positions of the first to fourth regions, the fifth region, the sixth region, and the seventh region on the display device one by one to the first to fourth embodiments. It is.
[0123]
FIG. 15 shows a part of the automatic device size determination device according to the present embodiment that differs from the first embodiment.
[0124]
The specification change processing unit 163 has substantially the same configuration as the specification change processing unit 155 shown in FIG. 14, except that the specification analysis unit 108 replaces the specification analysis unit 160 and the modified specification plan determination unit 151 executes The point is that the region information 162 is output from both the specification analysis unit 160 and the modified specification plan determination unit 161 instead of the plan determination unit 161.
[0125]
The specification analysis unit 160 is obtained by adding a function of outputting the area information 162 to the specification analysis unit 108.
[0126]
The modified specification plan determining unit 161 is obtained by adding a function of outputting the area information 162 to the modified specification plan determining unit 151.
[0127]
The area information 162 is sent to the screen output unit 164, and outputs an image such as FIG. 2 or FIG. 10 that allows the positional relationship of each area to be grasped as visual information.
[0128]
It is also possible to display the upper and lower limits of the allowable specification change range of the correction condition 152. As an example, FIG. 16 shows a state in which a range in which the first area F1 changes to the area F1 ′ is displayed when a condition is set for the change range of the constraint condition on the layout.
[0129]
As described above, according to the present embodiment, the designer can grasp the positions of the first area to the seventh area one by one, and can automatically determine the size by reducing the man-hour particularly when the specification is manually changed. .
[0130]
【The invention's effect】
As described above, according to the present invention, when determining a device size based on device information in a circuit design, it is possible to determine the size even if the size cannot be determined due to the contents of the input specifications. By modifying the specifications, the design man-hours and design defects are reduced, and the specifications are modified according to the wishes of the designer, so that the device size automatic deciding device with higher perfection can be achieved. And a method can be realized.
[Brief description of the drawings]
FIG. 1 is an explanatory diagram showing a configuration of a device size determination device according to a first embodiment of the present invention.
FIG. 2 is a diagram showing an example when a fifth area exists.
FIG. 3 is a diagram showing an example when a fifth area does not exist;
FIG. 4 is a model diagram showing a configuration and a processing flow of a modified specification determining unit in FIG. 1;
FIG. 5 is a schematic diagram for explaining processing performed by a specification change processing unit in FIG. 4;
FIG. 6 is an explanatory diagram showing a configuration of a device size determination device according to a second embodiment of the present invention.
FIG. 7 is a diagram showing an example in which a fifth area does not exist due to extreme specifications.
FIG. 8 is a diagram showing an example of an undesirable case as a result of specification modification from the case of FIG. 7;
FIG. 9 is an explanatory diagram showing a configuration of a device size determination device according to a third embodiment of the present invention.
FIG. 10 is a schematic diagram for explaining a process performed by a fifth area adjustment unit in FIG. 9 (when a seventh area exists);
FIG. 11 is a schematic diagram for explaining a process performed by a fifth area adjustment unit in FIG. 9 (when the seventh area does not exist);
FIG. 12 is a model diagram showing a flow of processing performed by a fifth area adjustment unit in FIG. 9;
FIG. 13 is an explanatory diagram of a process performed in creating the sixth area analysis specification in FIG. 12;
FIG. 14 is an explanatory diagram showing a configuration of a device size determination device according to a fourth embodiment of the present invention.
FIG. 15 is an explanatory diagram showing a configuration of a device size determination device according to a fifth embodiment of the present invention.
FIG. 16 is a schematic diagram for explaining processing of a screen output unit in FIG. 15;
FIG. 17 is a model diagram showing a configuration and a processing flow of a conventional resistance element automatic size determination processing unit.
FIG. 18 is a diagram showing an example of a resistance element shape.
FIG. 19 is a model diagram showing a configuration of an additional examination processing unit for high-accuracy design
[Explanation of symbols]
101 Specifications
102 Automatic size determination processing unit
103 Success / failure determination unit
104 Result output
105 Device Characteristics Database
108 Specification Analysis Department
109 Correction specification draft decision unit
110 Draft Specification
111 Size determination unit
112 Specification change processing unit
120 State discriminator
121 Specification adjustment unit
122 area discriminator
123 vs. default comparison section
124 Abnormal specification change unit
125 area discriminator
130 Abnormal specification discriminator
131 Abnormal Specification Correction Section
132 Specification change processing unit
135 state determination unit
136 5th area adjustment unit
140 Creating specifications for 6th area analysis
141 Specification for 6th area analysis
142 End judgment
143 W increase
145 Position comparison
146 Specification change
147 Seventh Area Existence Determination
150 Correction method branch
151 Modification specification draft decision unit
152 Modification condition specification section
153 Correction conditions
154 confirmation
155 Specification change processing unit
160 Specification Analysis Department
161 Modified specification draft decision unit
162 area information
163 Specification change processing unit
164 screen output unit

Claims (18)

A device size determination apparatus for inputting design specifications of a device constituting a semiconductor integrated circuit and determining a device size according to the input specification,
A device characteristic storage unit that stores device characteristic values for each device size,
A size determination unit that refers to the device characteristic value of the device characteristic storage unit and determines a device size according to the input design specification;
When it is impossible to determine the device size, comprising a specification change unit that changes the design specification,
The device size determination device, wherein the size determination unit redetermines a device size according to the design specification changed by the specification change unit. 2. The device size determination device according to claim 1, wherein a size constraint condition on a layout, an allowable variation condition, an allowable mismatch condition, and an allowable simulation error condition are input as the design specifications. When it is impossible to determine the device size because there is no device size region that satisfies all the conditions input as the design specifications at the same time, the specification change unit sets the region in the device size region that satisfies each of the above conditions. 3. The device size determination device according to claim 2, wherein one of the conditions is selected and changed based on the obtained positional relationship information so that a size region that satisfies all of the above conditions simultaneously exists. 4. . The specification change unit checks whether or not an abnormal specification has been input according to a predetermined rule, and if an abnormal specification exists, the abnormal specification is performed so that a size area that simultaneously satisfies all the conditions input as the design specification exists. The device sizing apparatus according to claim 2, wherein the specification is modified. If there is a device size region that simultaneously satisfies all the conditions input as the design specifications, but the device size cannot be determined, the specification change unit selects from the conditions according to a predetermined rule. The device size determination device according to claim 2, wherein a size region that satisfies all of the above conditions is enlarged by changing any of the conditions. When it is impossible to determine the device size even though there is a device size region that satisfies all the conditions input as the design specifications at the same time, the specification change unit performs a predetermined voltage condition regardless of the condition. A size region that satisfies only the device characteristic condition under the temperature condition or the device characteristic condition under the predetermined current condition and the temperature condition is obtained, and this region overlaps with the region that simultaneously satisfies all the conditions input as the design specifications. As described above, by changing any one of the conditions input as the design specifications in accordance with a predetermined rule, a size region that simultaneously satisfies all the conditions input as the design specifications is expanded. A device size determination device according to claim 1. The device size determination device according to any one of claims 1 to 6, wherein the specification change content is confirmed by the specification change unit, and when the change content is not satisfied, the specification change unit is caused to change the specification again. The specification change unit further includes a condition specification unit for inputting information for designating a priority of the specification change, prohibition of the change, a range in which the change is permitted, or information for directly instructing the specification change. The device size determination apparatus according to any one of claims 1 to 7. The device according to claim 8, further comprising a display unit configured to display a positional relationship of specification conditions changed according to the information in accordance with the information input from the condition specifying unit and an upper and lower limit of an allowable change range. Sizing device. Enter the design specifications of the devices that make up the semiconductor integrated circuit,
Refer to the device characteristic value stored in the device characteristic storage unit for each device size, determine the device size according to the input design specification,
If the determination of the device size is impossible or the determination result is inappropriate, change the design specification,
A device size determination method characterized by re-determining a device size according to a changed design specification. The device size determination method according to claim 10, wherein a size constraint condition on a layout, an allowable variation condition, an allowable mismatch condition, and an allowable simulation error condition are input as the design specifications. When it is impossible to determine the device size because there is no device size region that simultaneously satisfies all of the conditions input as the design specifications, examine the positional relationship of the device size region that satisfies each of the above conditions, 12. The device size determination method according to claim 11, wherein one of the conditions is selected and changed based on the obtained positional relationship information so that a size area that satisfies all of the conditions at the same time exists. It checks whether or not an abnormal specification has been input by a predetermined rule, and if an abnormal specification exists, corrects the abnormal specification so that there is a size area that simultaneously satisfies all the conditions input as the design specification. Item 12. The device size determining method according to Item 11. If there is a device size area that simultaneously satisfies all the conditions input as the design specifications, but it is impossible to determine the device size, change any of the conditions selected from the above conditions according to a predetermined rule The device size determination method according to claim 11, wherein a size region that satisfies all of the above conditions is simultaneously enlarged. When the device size cannot be determined even though there is a device size region that simultaneously satisfies all the conditions input as the design specifications, the device characteristics under a predetermined voltage condition and temperature condition regardless of the condition A condition or a size region that satisfies only a device characteristic condition under a predetermined current condition and a temperature condition is determined, and a predetermined rule is set such that this region and a region that simultaneously satisfies all the conditions input as the design specifications have an overlap. 12. The device size determination according to claim 11, wherein a size region that simultaneously satisfies all of the conditions input as the design specifications is enlarged by changing one of the conditions selected from the conditions input as the design specifications in accordance with the following. Method. The device size determination method according to any one of claims 10 to 15, wherein the specification change content is confirmed, and the specification change is performed again when the change content is not satisfied. Steps to change the specification by inputting information that specifies the priority of specification change, prohibition of change, and the range in which change is permitted, or input information that directly instructs specification change and change the specification as per the information The method according to claim 10, further comprising the step of: 18. The device size determination method according to claim 17, further comprising a step of displaying, in response to the input of the information, a positional relationship between specification conditions changed according to the information and a positional relationship between upper and lower limits of an allowable change range.

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