# Patent

## Title
Computer recording medium for storing program of checking design rule of layout

## Abstract

A method for checking a design rule of layout and a computer readable recording medium for storing program thereof are provided. A layout comprising a plurality of layers is united so as to generate a flag layer to check the layout, through which any information about characters in the layout can be identified. Characters in the layout can be used in general command file to inspect the checking of the design rule for the purpose of saving time and manual effort.

## Background
BACKGROUND OF THE INVENTION
1. Field of Invention
The present invention relates to a method for checking a design rule of layout. More particularly, the present invention relates to a method for inspecting the design rule of layout according to the characteristics of layers in the layout.
2. Description of Related Art
In the design and development of semiconductor chips, the design rule check (DRC) is a program for checking whether the semiconductor integrated circuit follows the topological layout rules (TLR) or not. The topological layout rules have particular rules depending on different process techniques and instrument limitation between wafer factories.
Referring to FIG. 1, it is a conventional flow chart of a method for inspecting whether semiconductor integrated circuits meet the design rules or not, which comprises the following steps.
First, as shown in step 110, a layout comprising a plurality of layers and being in global distribution system (GDS) format is provided. Then, as shown in step 120, the corresponding topological layout rules are determined in manual manner according to different process techniques, conditions of wafer factories, and characters in chips. Next, as shown in step 130, according to the topological layout rules determined in step 120, a corresponding command file is fetched from a prepared command file database 140. In step 150, the layout is inspected and checked by using the design rule check tool according to this command file. Any design error found in the process is shown in the check result 160.
As for the conventional design rule check flow, engineers must design different command files for different process techniques. As current design rule check tools cannot provide information about whether a certain layer exists in the layout or not, it is necessary to manually search the maximum number of layers and select the corresponding command file according to different wafer sizes. No matter whether a suitable program is selected from the design command file database or from the command file database according to the characters in chips so as to perform the design rule check, a large amount of time will be spent which further negatively affects the whole flow of IC design.
SUMMARY OF THE INVENTION
In view of the above, an objective of the present invention is to provide a method for checking the layout design rule, so as to find out characters of a certain layout and perform the design rule check according to the characters.
Another objective of the present invention is to provide a computer readable recording medium, so as to find out the characters of layout to be checked and perform the design rule check according to the characters.
Still another objective of the present invention is to provide a method for checking the layout design rule, so as to check the layers and compare the layers with a flag layer and perform an identified rule according to the size of flag layer.
Based on the above and other objectives, the present invention provides a method for checking the layout design rule, suitable for inspecting whether a layout meets the design rule or not. The method for checking the layout design rule of the present invention includes uniting a layout comprising a plurality of layers, a flag layer obtained by uniting a part of or all the layers in the layout, and checking the layout according to the flag layer.
According to the method for checking the layout design rule in a preferred embodiment of the present invention, if the comparison result of a certain layer with the flag layer is the empty set, it indicates that the layer does not exist in the layout. Otherwise, if the comparison result is the nonempty set, it indicates that the layer exists in the layout. In these existing layers, the layer located at the top place is the top layer in the layout, and other existing layers are referred to as the inner layers. The design rule check respectively uses different rules to check whether the top layer and the inner layers meet the design rule or not.
According to the method for checking the layout design rule in a preferred embodiment of the present invention, the layout is compared with the flag layer to identify the top layer in the layout. First, the graphic TOPMN is set to be equal to the graphic with maximum layer number in the layout. Then, it is checked that whether or not the flag layer BULK and the graphic TOPMN have no intersection, if yes, the graphic NO_MN—BULK is set to be the graphic of the flag layer BULK, otherwise the graphic NO_MN—BULK is set to be the empty set. Thereafter, each of the layers in the layout is checked successively from top to bottom. If the layer MEi and the graphic NO_Mi+1—BULK of the ith layer in the layout have the intersection, the graphic TOPMi is set to be the graphic MEi of the ith layer, otherwise TOPMi is set to be the empty set, wherein i is an integer greater than 0 and less than N. If the graphic NO_Mi+1—BULK and the graphic TOPMi have no intersection, the graphic NO_Mi—BULK is set to be equal to NO_Mi+1—BULK, otherwise the NO_Mi—BULK is set to be the empty set. Finally, the graphics TOPMN ̃TOPMj are united to obtain the graphic of the top layer in the layout, wherein j indicates a minimum value of the number of layers capable of becoming the top layer in the layout.
According to the method for checking the layout design rule of a preferred embodiment of the present invention, it is determined whether to perform a large size identified rule or a small size identified rule to the layout design rule check according to the comparison result of the flag layer with a reference size.
The result obtained from comparing the flag layer with the layout is used as parameters in the command file to perform the proper design rule check.
From another viewpoint, the present invention provides a computer readable recording medium, in which a layout can be checked by performing the programs stored in this medium on the computer system. The programs in the recording medium include reading the instructions of the layout having a plurality of layers, obtaining a flag layer by uniting a part of or all the layers in the layout, and checking whether or not the layout follows the design rule according to the flag layer.
According to the computer readable recording medium in a preferred embodiment of the present invention, the instructions of the program in the above medium include comparing a layer in the layout with the flag layer. If the comparison result is the empty set, it indicates that the layer does not exist. If the comparison result of a layer in the layout with the flag layer is the nonempty set, it indicates that the layer exists in the layout. The top layer in the existing layers is regarded as the top layer in the layout, and other existing layers are regarded as the inner layers. The design rule check uses different check rule according to whether or not the layer is the top layer.
According to the computer readable recording medium in a preferred embodiment of the present invention, the layout is compared with the flag layer to determine that the first instruction of the uppermost layer in the layout sets the graphic TOPMN to be equal to the graphic with the maximum possible number of layers in the layout. The second instruction checks whether or not the flag layer BULK and the graphic TOPMN have no intersection. If yes, the graphic NO_MN—BULK is set to be the graphic of the flag layer BULK, otherwise the graphic NO_MN—BULK is set to be the empty set. The third instruction checks each of the layers in the layout successively from top to bottom. If the ith layer MEi in the layout and the graphic NO_Mi+1—BULK have the intersection, the graphic TOPMi is set to be the graphic of the ith layer MEi, otherwise the TOPMi is set to be the empty set, wherein i is an integer greater than 0 and less than N. If the graphic NO_Mi+1—BULK and the graphic TOPMi have no intersection, the graphic NO_Mi—BULK is set to be equal to the NO_Mi+1—BULK, otherwise the NO_Mi—BULK is set to be the empty set. The last instruction unites the graphics TOPMN ̃TOPMj to obtain the graphic of the top layer in the layout, wherein j indicates a minimum value of the number of the layers capable of becoming the top layer in the layout.
According to the computer readable recording medium in a preferred embodiment of the present invention, the program instructions in the above medium also include comparing the graphic of the flag layer with a reference size. If the flag layer is larger than the reference size, a large size identified rule is used. Otherwise, if the flag layer is smaller than the reference size, a small size identified rule is used to check whether or not the layout meets the design rule.
The program in the readable recording medium acquires the desired parameters by comparing the layout and the flag layer, and uses the parameters in the command file to perform the design rule check.
From another viewpoint, the present invention provides a method for checking the layout design rule used to inspect whether or not a layout meets the design rule check. The method for checking the layout design rule of the present invention includes a layout having a plurality of layers, a flag layer obtained by uniting a part of or all the layers in the layout, comparing the layers with the flag layer and checking the layers, and comparing the graphic size of the flag layer with a reference size to perform the identified rule.
According to the method for checking the layout design rule in a preferred embodiment of the present invention, the step for comparing the layers with the flag layer and checking the layers includes comparing the layers in the layout respectively with the flag layer. If the comparison result is the empty set, it indicates that the layer does not exist in the layout. In all the layers existing in the layout, the uppermost one is referred to as the top layer in the layout, and the other layers are referred to as the inner layers. The top layer rule check is used in the design rule check of the top layer, and the internal rule check is used to check the inner layers in the layout.
The present invention employs a method for checking the layout design rule, in which the characters in the layout are obtained according to the flag layer generated by the layout, and generates proper parameters according to the characters of the content such that the parameters can be used in a general command file to perform the design check. According to this method, it is not required to manually select the command file for the design rule check in accordance with different process techniques or chip characters, etc, so as to inspect the design rule check.
In order to make the aforementioned and other objectives, features and advantages of the present invention comprehensible, preferred embodiments accompanied with figures are described in detail below.



BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 shows a flow chart of the conventional layout design rule check.
FIGS. 2 and 10 show flow charts of the method for checking the layout design rule.
FIG. 3 shows a flow chart of the method for checking the layout according to the flag layer in the method for checking the layout design rule.
FIG. 4 shows a flow chart of the method for comparing the layout with the flag layer to obtain the top layer.
FIGS. 5, 7, and 8 show an embodiment of the program of the design check rule.
FIG. 6 shows a flow chart of the method for determining the size identified rule.
FIG. 9 shows a flow chart of the program stored in a computer readable recording medium and being provided with a function of checking whether or not a layout follows the design rule.



DESCRIPTION OF EMBODIMENTS
The First Embodiment
FIG. 2 is a flow chart of the method for checking the layout design rule according to a preferred embodiment of the present invention. As shown in FIG. 2, this method mainly uses a method for checking the layout design rule and a common command file 240 to perform a design rule check 250 in the format of such as global distribution system (GDS) and generate a result 260 of the rule check.
First, as shown in step 210, a layout is provided, wherein the layout comprises a plurality of layers. In this embodiment, the layout is a GDS format file.
Second, as shown in step 220, a part of or all the layers in the layout are united to obtain a flag layer. In this embodiment, all the layers in the layout are combined to obtain a flag layer called BULK.
Third, as shown in step 230, the layout is checked according to the flag layer BULK.
According to the demands of users, various check items can be performed in step 230. The user can write the command of the items to be checked in a general command file beforehand. As shown in FIG. 3, it is a flow chart illustrating the substeps in the step 230 according to an embodiment of the present invention. Referring to FIG. 3, as shown in step 310, the layers in the layout are respectively compared with the flag layer. If the comparison result of a certain layer in the layers with the flag layer is the empty set, it indicates that the layer is an empty layer (step 320). If the comparison result of a certain layer in the layers with the flag layer is not the empty set, in the layers with the comparison result of nonempty set, the uppermost layer is referred to as the top layer in the layout, and the other existing layers which are not the top layer are the inner layers in the layout (step 330). According to the comparison result, an top layer rule is used to check the uppermost layer in the layout (step 340), and an inner layer rule is used to check the inner layers in the layout (step 350).
Referring to FIGS. 3 and 4, in the step 330 of FIG. 3, the details of the method for identifying the uppermost layer in the layout are described as follows. First, the graphic TOPMN is set to be equal to the graphic MEN of the Nth layer in the layout, wherein N is the maximum number of layers in the layout (step 410). In step 420, check whether or not the flag layer BULK and the graphic TOPMN have no intersection. If yes, the graphic NO_MN—BULK is set to be equal to the graphic of the flag layer BULK, otherwise the graphic NO_MN—BULK is set to be the empty set. In step 430, if the ith layer MEi in the layout and the graphic NO_Mi+1—BULK have the intersection, the graphic TOPMi is set to be equal to the graphic MEi of the ith layer in the layout, otherwise the graphic TOPMi is set to be the empty set, wherein the i is an integer greater than 0 and less than N. In step 440, check whether or not the graphic NO_Mi+1—BULK and the graphic TOPMi have no intersection, the graphic NO_Mi—BULK is set to be equal to the graphic NO_Mi+1—BULK, otherwise the graphic NO_Mi—BULK is set to be the empty set. The graphic TOPMi generated in the above steps is equal to the graphic of the ith layer only when the value of i is not the number of the top layer in the layout, otherwise it is set to be the empty set. In step 450, the graphics TOPMN ̃TOPMj are united to obtain the graphic of the top layer in the layout, wherein j indicates a minimum value of the possible range of the top layer in the layout.
In the method for checking the layout design rule, by comparing the flag layer and the layout, the graphic of the layers except the top layer in the layout can be found. First, check whether or not the graphic MEi of the ith layer in the layout and NO_Mi+1—BULK have the intersection. If no, the graphic COMMi is set to be equal to the graphic MEi. If yes, the COMMi is set to be the empty set. The graphic of COMMi not being equal to the empty set indicates that the graphic is the graphic of ith layer which is not the top layer in the layout, wherein i is an integer greater than 0 and less than N.
If N is the maximum possible number of layers in the layout, the graphic LSMN−1 is set to be equal to the graphic of the N−1th layer in the layout. This method for checking the layout design includes checking the N−1th to the first layer successively from top to bottom. If the graphic COMMk (K is an integer greater than 0 and less than N−1) and the graphic NO_Mk+2—BULK have the intersection, the LSMk is set to be equal to COMMk, otherwise the LSMk is set to be the empty set. Only the graphic LSMk of the layer k just below the top layer in the layout is not the empty set, and thus the LSMN−1 ̃LSM1 can be united to obtain the graphic of the layer just below the top layer in the layout.
Here, a layout having a maximum possible number of layers of 11 is taken as an example. FIG. 5 shows an example of the command file used for the design rule check of the Calibre program of Mentor Company in an embodiment of the present invention. It should be noted that for the purpose of convenience of illustration FIG. 5 only a part of the content of the general command file is shown. According to the above step 220 of FIG. 2, the flag layer BULK is the union of metal layers 1 to 11 in the layout. Referring to the command code block 510 in FIG. 5, if it is desired to obtain the graphic information of the top layer from the GDS format layout, first the graphic TOPM11 is set to be the graphic of the 11th metal layer ME11. Next, as shown in step 420 ̃step 440 in FIG. 4, the content of TOPMi and NO_Mi—BULK is set, wherein i is an integer greater than 0 and less than 11. In this embodiment, the top layer in the layout is assumed to be the 10th metal layer, and the 1st metal layer to the 3rd metal layer definitely exist in the process, and thus the minimum value j of the possible range of the top layer in the layout (GDS file) is 4.
Referring to FIGS. 4 and 5 at the same time, according to step 410 ̃step 450, after the instruction “TOPM11=COPY ME11” is executed, the graphic TOPM11 is set to be the graphic of the 11th metal layer that does not exist, which is the empty set in this embodiment. As the flag layer BULK and the graphic TOPM11 of the 11th layer (the empty set herein) have no intersection, after the instruction “NO_M11_BULK=BULK NOT INTERACT TOPM11” is executed, a flag layer NO_M11—BULK without the 11th metal layer is set to be BULK. Since the uppermost metal layer in the layout is assumed to be the 10th metal layer in this embodiment, i.e., the 10th metal layer and the graphic NO_M11—BULK set as BULK definitely have the intersection, after the instruction “TOPM10=ME10 INTERACT NO_M11_BULK” is executed, TOPM10 is set to be the graphic ME10. Additionally, as the NO_M11—BULK and TOPM10 have the intersection, after the instruction “NO_M10_BULK=NO_M11_BULK NOT INTERACT TOPM10” is executed, the NO_M10—BULK is set to be the empty set. After the instruction “TOPM9=ME9 INTERACT NO_M10_BULK” is executed, the graphic ME9 of the ninth metal layer and NO_M10—BULK which is the empty set in this embodiment have no intersection, the TOPM9 is set to be the empty set. In this way, the value of TOPM8 ̃TOPM4 can be obtained. In the method of comparing the flag layer and the layout to obtain the top layer, only the graphic of TOPM10 corresponding to the top layer 10 is designated to be ME10 in this embodiment. Graphics TOPM4 ̃TOPM9 and TOPM11 are all set to be the empty set. By uniting the graphics TOPM4 to TOPM11, the graphic of the top layer in this layout can be obtained.
Then, referring to the command code block 520 of FIG. 5, after the instruction “COMM10=(ME10 NOT INTERACT NO_M11_BULK) NOT TOPM10” is executed, the graphic of the 10th metal layer in the layout and the graphic NO_M11—BULK have the intersection, thus the graphic COMM10 is the empty set. Since the 9th metal layer and the graphic NO_M10—BULK that is the empty set have no intersection, after the instruction “COMM9=(ME9 NOT INTERACT NO_M10_BULK) NOT TOPM9” is executed, the graphic COMM9 is set to be the graphic of the 9th metal layer ME9. In this way, whether or not the other layers are the inner layers in the layout can be deduced by the command code block 520.
Referring to the command code block 540 of FIG. 5, the instruction “LSM10=COPY COMM10” sets LSM10 to be graphic COMM10, which is the empty set in this embodiment. As the graphic COMM9 (the graphic of ME9 herein) and NO_M11—BULK have the intersection, after the instruction “LSM9=COMM9 INTERACT NO_M11_BULK” is executed, the graphic LSM9 is the graphic of COMM9. As the graphic COMM8 (the graphic of ME8 herein) and the graphic NO_M10—BULK (which is the empty set here) have no intersection, after the instruction “LSM8=COMM8 INTERACT NO_M10_BULK” is executed, the value of the graphic LSM8 is set to be the empty set. In this way, except that the graphic LSMi corresponding to the metal layer just below the top layer (the top layer is assumed to be the 10th metal layer ME10 in this embodiment) of the layout is equal to the graphic COMMi, the LSMk of the other layers is the empty set. Thus, in this embodiment, LSM10 ̃LSM3 can be united to obtain the graphic of the layer just below the top layer in this layout (it is assumed to be the 9th metal layer ME9 in this embodiment).
In FIG. 5, the command code block 520 and the command code block 530 can automatically analyze the information of the top via of the top layer and the internal top via in the layout according to the similar logic. The command code block 550 substitutes all the variable values previously obtained into the parameter positions required by the command file instruction to perform the layout design rule check.
According to the conventional art, first the GDS format layout file must be opened, and which layer in the layout is the uppermost metal layer is checked manually. Taking the process of 1P5M as an example, the user must manually check to confirm that the uppermost metal layer in the layout is disposed at the 5th metal layer, and then select a command file suitable for the 1P5M process from a plurality of command files, so as to perform the “design rule check” to the layout. Compared with the conventional art, a single command file is required in the embodiment of the present invention. As the uppermost metal layer in the layout can be automatically identified from the command file, the present invention can automatically perform the design rule check without requiring manpower.
The Second Embodiment
The user may carry out other check items in step 230 as required, and write the command of the item to be checked into the common command file beforehand. FIG. 6 shows a flow chart illustrating the substeps in step 230 according to the embodiment of the present invention. Referring to FIGS. 2 and 6 together, in step 220, a part of or all the layers in the layout are united to obtain a flag layer. In this embodiment, all the layers in the layout can be united to obtain a flag layer called PSUB. In the step 230 of FIG. 2, the information required by the die corner rule can be generated by checking the layout according to the flag layer. In step 610 of FIG. 6, the flag layer obtained by uniting all the layers in the layout is compared with a reference size. As shown in step 620, when the size of the flag layer is larger than the reference size, a large size identified rule is performed. Otherwise, if the size of the flag layer is smaller than the reference size, a small size identified rule is performed (as shown in step 630). The method for performing the identified rule involves first setting the graphic B_BCOR to be equal to the corner graphic of the flag layer, intersecting the graphic Mh of the hth metal layer in the layout and the graphic B_BCOR, and setting the intersection result to be the graphic METhCA, wherein h is an integer greater 0 and less than N+1, and N is the maximum number of layers in the layout. Finally, it is checked whether or not a part of the graphics is not arranged at an angle of 45° in the graphic METhCA.
Taking a layout with the maximum number of layers of 6 as an example, FIG. 7 is an example of a command file of the design rule check used in DRACULA program of Cadence Company in the embodiment of the present invention. As shown in the command code block 710, first the values of S_PSUB and B_PSUB are set according to the size of the flag layer PSUB. In this embodiment, the flag layer PSUB is the union of the graphics of layers 1 to 6. If the size of the flag layer PSUB is between 0 and 100 mm2, the graphic S_PSUB is set to be PSUB, and the graphic B_PSUB is the empty set. Otherwise, if the size of the flag layer is larger than 100 mm2, the graphic B_PSUB is set to be the graphic of the flag layer PSUB and the graphic S_PSUB is the empty set. The command code block 720 is the part of the program executed by the design rule check when the flag layer PSUB meets the large size identified rule, i.e. when the size of the flag layer PSUB is larger than 100 mm2. The command code 721 designates the range of the corner graphic B_BCOR according to the graphic B_PSUB. In this embodiment, B_BCOR is a graphic constituted of four squares with the side length of 340 um respectively counted from the internal angles of 4 dies. The command code block 723 respectively sets the graphic MET1CA to the graphic MET6CA to be the graphics in layers 1 to 6 that has the intersection with the B_BCOR. The command code block 725 finds out the graphics arranged at an angle of 45° in the graphics MET1CA to MET6CA. The command code block 727 finds out the graphics not arranged at an angle of 45° in the graphics MET1CA to MET6CA, which are considered to be errors and then output.
The command code block 730 checks errors through the similar flows according to the small size identified rule. The command code 731 sets the range of the corner graphic S_BCOR used in the small size identified rule check. In this embodiment, the graphic S_BCOR is a graphic constituted of four squares with the side length of 125 um respectively counted from the corners of 4 dies. The command code blocks 733, 735, and 737 check out the graphics intersected with the corner graphics and not arranged at an angle of 45° in the layers 1 to 6, which are considered to be errors and then output.
In the conventional art, first the GDS format layout file must be opened, and then the size of the layout is manually measured to determine which identified rule the layout is suitable for. And the content of the command file is modified according to the manually checked result, making the content meets the corresponding size identified rule. Compared with the conventional art, after the embodiment of the present invention executes the command code block 710, the size of the layout can be automatically determined. If the size of the flag layer is between 0 and 100 mm2, as the graphic B_PSUB is the empty set, the check result is not affected after the large size identified rule described in the command code block 720 is executed. Otherwise, if the size of the flag layer is larger than 100 mm2, as the graphic S_PSUB is the empty set, the check result is also not affected after the small size identified rule described in the command code block 730 is executed and the rule design check is performed. Differing from the conventional art, in the present invention, it is not required to manually check the size of the layout. Only a single command file is used to check the layout no matter whether it is checked based on the large size identified rule or the small size identified rule.
The Third Embodiment
The user can carry out other check items in the step 230 of FIG. 2 as required, for example, check whether or not a specific layer exists in the layout, and write the command of the item to be checked in the common command file 240 beforehand. The flag layer generated by uniting all the layers in the layout can be used to check whether or not a specific layer exists in the layout. Here, checking whether or not the layer NPLUS exists in a GDS format layout is taken as an example to illustrate another possible embodiment of the present invention. FIG. 8 is an example of a command file of the design rule check used for the Calibre program of Mentor Company according to an embodiment of the present invention.
Referring to FIG. 8, in order to clearly illustrate the point of this embodiment, FIG. 8 only shows a part of the content in the common command file. The command code block 810 defines ACTIVE_NW and ACTIVE_PS according to the relationship of the diffusion DIFF graphic and the N-type well NWEL graphic, and then defines NDIF and NTAP respectively according to the relationship of the graphic ACTIVE_NW, ACTIVE_PS and the layer NPLUS. As shown in the command code block 820, if the layer NPLUS and a flag layer BULK obtained by uniting all the layers in the layout have the intersection, it indicates that the layer NPLUS exists in this layout, thus setting the graphic X to be the graphic of the flag layer BULK. Otherwise, if the layer NPLUS and the flag layer BULK have no intersection, it indicates that the layer NPLUS does not exist, thus setting the graphic X to be the empty set.
The command code block 830 is used to output the check result. If the graphic NDIF and the graphic X have the intersection, the graphic of the layer NPLUS is deducted from the graphic NDIF and then output. If the graphic NTAP and the graphic X have the intersection, the graphic of the layer NPLUS is deducted from the graphic NTAP and then output. Therefore, the design rule check is performed to the two graphics NDIF and NTAP defined in the command code block 810 beforehand by using the result to check whether or not the layer NPLUS exists in the layout (in this embodiment, the check result is stored in a region variable X).
In the conventional art, if it is required to check whether or not a specific layer exists in the layout, first the GDS format layout file must be opened, and then the layout file must be checked manually. However, compared with the conventional art, the present invention uses a flag layer generated by uniting all the layers in the layout to accurately determine whether or not a specific layer exists in the layout, and further automatically output the check result.
The Fourth Embodiment
FIG. 9 is a flow chart of a program capable of performing the layout design rule check according to the preferred embodiment of the present invention. This program can be stored in a computer readable recording medium such as a hard disk, an optical disk, or a magnetic disk. Referring to FIG. 9, this program can be used to check whether or not the GDS format layout in this embodiment meets the design rule.
As shown in step 910, this program reads the layout having a plurality of layers. In step 920, the program unites a plurality of layers or all the layers in the layout to obtain a flag layer. In step 930, whether or not the layout follows the design rule is checked according to the flag layer. The above step 920 and step 930 can be implemented referring to the above embodiments, and the details will not be repeated herein.
In the conventional art, the GDS format layout file must be opened, and through a manual check the information of layout is obtained, and the suitable command file is found according to the information to perform the design rule check. Different from the conventional art, the embodiment of the present invention can provide the information about the top layer, the inner layers, the layer just below the top layer, etc. of the layout by comparing the flag layer and the layout. The flag layer can be used to determine whether or not the layout is suitable for the large size or the small size identified rule. The information is used in a single command file to automatically perform the design rule check.
The Fifth Embodiment
Referring to FIG. 10, it is a flow chart of a method for checking the layout design rule of a layout according to the preferred embodiment of the present invention.
The steps of the check method are described as follows. In step 1010, a layout having a plurality of layers is provided. In step 1020, a part of or all the layers are united to obtain a flag layer according to the layout. In step 1030, the flag layer is compared with each of the layers in the layout, thereby checking the layers. In step 1040, the graphic of the flag layer is compared with a reference size, thereby performing the corresponding identified rule. The above steps 1020, 1030, and 1040 can be implemented with reference to the above embodiments, and the details will not be repeated herein again.
Different from the conventional art, the layout is manually checked and then the command file suitable for the layout is found to perform the rule check. The embodiment of the present invention may attain the parameters of the command file required for the design check by comparing the layers with the flag layer, such as the graphic of the top layer, the graphic of the layer just below the top layer, the graphic of the inner layer, or the range of the size of the layout, so as to automatically perform the design rule check.
In view of the above, in the method for checking the layout design rule and the computer readable recording medium of the present invention, the parameters required for a single command file are generated by comparing the flag layer and the layout. The corresponding design rule check is automatically performed according to the parameters. The automation can save a large amount of time and also reduce the errors resulting from the manual judgment, so as to improve the production efficiency in the semiconductor industry.
It will be apparent to those skilled in the art that various modifications and variations can be made to the structure of the present invention without departing from the scope or spirit of the invention. In view of the foregoing, it is intended that the present invention cover modifications and variations of this invention provided they fall within the scope of the following claims and their equivalents.

## Claims

1. A computer readable recording medium storing thereon a program, which causes a computer system to perform a method for checking a layout, the method comprising:
reading the layout, wherein the layout comprises a plurality of layers;
uniting a part of or all the layers in the layout to obtain a flag layer;
checking the layout according to the flag layer; and
generating a result of the checking, for inspecting whether the layout meets design rule or not.

2. The computer readable recording medium as claimed in claim 1, wherein the layout is a GDS (global distribution system) format file.

3. The computer readable recording medium as claimed in claim 1, wherein the flag layer is a union of all the layers in the layout.

4. The computer readable recording medium as claimed in claim 1, wherein the step for checking the layout according to the flag layer comprises:
comparing each of the layers in the layout with the flag layer:
if a certain layer in the layers with the flag layer is empty set, indicating that said certain layer is an empty layer; and
if the result of the comparing for a certain layer in the layers with the flag layer is nonempty set, in the layers with the result of the comparing being nonempty set, the uppermost layer is the top layer in the layout, and other layers below the top layer are the inner layers in the layout;
checking the top layer in the layout based on a top layer rule; and
checking the inner layers in the layout based on an inner layer rule.

5. The computer readable recording medium as claimed in claim 4, wherein the step for comparing each of the layers in the layout with the flag layer comprises:
setting graphic (TOPMN) corresponding to an Nth top layer to be equal to graphic of the Nth layer (MEN) in the layout, wherein N is a maximum number of layers in the layout;
if the flag layer (BULK) and the graphic (TOPMN) have no intersection, setting graphic (NO_MN—BULK) to be equal to graphic of the flag layer (BULK), otherwise setting the graphic (NO_MN—BULK) to be empty set, wherein the graphic (NO_MN—BULK) indicates the graphic of the flag layer without the Nth layer;
if graphic of the ith layer (MEi) in the layout and graphic (NO_Mi+1—BULK) have an intersection, setting graphic (TOPMi) to be equal to the graphic of the ith layer (MEi) in the layout, otherwise setting the graphic (TOPMi) to be empty set, wherein i is an integer greater than 0 and less than N;
if the graphic (NO_Mi+1—BULK) and the graphic (TOPMi) have no intersection, setting graphic (NO_Mi—BULK) to be equal to the graphic (NO_Mi+1—BULK), otherwise setting the graphic (NO_Mi—BULK) to be empty set; and
uniting the graphics (TOPMN ̃TOPMj) to obtain the top layer in the layout, wherein j indicates a minimum value of a possible range of the top layer in the layout.

6. The computer readable recording medium as claimed in claim 5, wherein the step for comparing each of the layers in the layout with the flag layer further comprises:
if graphic of the ith layer (MEi) in the layout and the graphic (NO_Mi+1—BULK) have no intersection, setting graphic (COMMi) to be equal to the graphic of the ith layer (MEi), otherwise setting the graphic (COMMi) to be empty set;
wherein the graphic (COMMi) indicates the graphic of one of layers except the top layer in the layout.

7. The computer readable recording medium as claimed in claim 6, wherein the step for comparing each of the layers in the layout with the flag layer further comprises:
setting graphic (LSMN−1) corresponding to a layer just below the Nth top layer to be equal to graphic of the (N−1)th layer (MEN−1) in the layout; and
if graphic (COMMk) and graphic (NO_Mk+213 BULK) have an intersection, setting graphic (LSMk) to be equal to the graphic (COMMk), otherwise setting the graphic (LSMk) to be empty set, wherein k is an integer greater than 0 and less than N−1;
wherein the graphic (LSMk) indicates the graphic of the layer just below the top layer in the layout.

8. The computer readable recording medium as claimed in claim 1, wherein the step for checking the layout according to the flag layer comprises:
comparing graphic size of the flag layer with a reference size;
if the graphic size of the flag layer is larger than the reference size, performing a large size identified rule; and
if the graphic size of the flag layer is smaller than the reference size, performing a small size identified rule.

9. The computer readable recording medium as claimed in claim 8, wherein the large size identified rule comprises:
setting corner graphic of the flag layer as graphic (B_BCOR);
intersecting graphic of the hth layer (MEh) in the layout and the graphic (B_BCOR), and setting a result of the intersecting as graphic (METhCA), wherein h is an integer greater than 0 and less than N+1, and N is a maximum number of layers in the layout; and
checking whether or not there is a part of the graphics not arranged at an angle of 45° in the graphic (METhCA).

10. A computer readable recording medium storing thereon a program, which causes a computer system to perform a method for checking a layout, the method comprising:
reading the layout, wherein the layout comprises a plurality of layers;
uniting a part of or all the layers in the layout to obtain a flag layer;
comparing the layers with the flag layer;
comparing graphic size of the flag layer with a reference size to determine an identified rule; and
generating a check result according to results of comparing the layers with the flag layer and comparing the graphic size of the flag layer with the reference size, for determining whether the layout meets design rule or not according to the check result.

11. The computer readable recording medium as claimed in claim 10, wherein the layout is a GDS (global distribution system) format file.

12. The computer readable recording medium as claimed in claim 10, wherein the flag layer is a union of all the layers in the layout.

13. The computer readable recording medium as claimed in claim 10, wherein the step for comparing the layers with the flag layer comprises:
comparing each of the layers in the layout with the flag layer;
if result of the comparing for a certain layer in the layers with the flag layer is empty set, indicating that said certain layer is an empty layer;
if the result of the comparing for a certain layer in the layers with the flag layer is nonempty set, in the layers with the result of the comparing being nonempty set, the uppermost layer is the top layer in the layout, and other layers below the top layer are the inner layers in the layout.

14. The computer readable recording medium as claimed in claim 13, wherein the step for comparing each of the layers in the layout with the flag layer comprises:
setting graphic (TOPMN) corresponding to an Nth top layer to be equal to graphic of the Nth layer (MEN) in the layout, wherein N is a maximum number of layers in the layout;
if the flag layer (BULK) and the graphic (TOPMN) have no intersection, setting graphic (NO_MN—BULK) to be equal to graphic of the flag layer (BULK), otherwise setting the graphic (NO_MN—BULK) to be empty set, wherein the graphic (NO_MN—BULK) indicates the graphic of the flag layer without the Nth layer;
if graphic of the ith layer (MEi) in the layout and graphic (NO_Mi+1—BULK) have an intersection, setting graphic (TOPMi) to be equal to the graphic of the ith layer (MEi) in the layout, otherwise setting the graphic (TOPMi) to be empty set, wherein i is an integer greater than 0 and less than N;
if graphic (NO_Mi+1—BULK) and the graphic (TOPMi) have no intersection, setting graphic (NO_Mi—BULK) to be equal to the graphic (NO_Mi+1—BULK), otherwise setting the graphic (NO_Mi—BULK) to be empty set; and
uniting the graphics (TOPMN ̃TOPMj) to obtain the top layer in the layout, wherein j indicates a minimum value of a possible range of the top layer in the layout.

15. The computer readable recording medium as claimed in claim 14, wherein the step for comparing each of the layers in the layout with the flag layer further comprises:
if graphic of the ith layer (MEi) in the layout and the graphic (NO_Mi+1—BULK) have no intersection, setting graphic (COMMi) to be equal to the graphic of the ith layer (MEi), otherwise setting the graphic (COMMi) to be empty set;
wherein the graphic (COMMi) indicates the graphic of one of layers except the top layer in the layout.

16. The computer readable recording medium as claimed in claim 15, wherein the step for comparing each of the layers in the layout with the flag layer further comprises:
setting graphic (LSMN−1) corresponding to a layer just below the Nth top layer to be equal to graphic of the (N−1)th layer (MEN−1) in the layout; and
if graphic (COMMk) and graphic (NO_Mk+2—BULK) have an intersection, setting graphic (LSMk) to be equal to the graphic (COMMk), otherwise setting the graphic (LSMk) to be empty set, wherein k is an integer greater than 0 and less than N−1;
wherein the graphic (LSMk) indicates the graphic of the layer just below the top layer in the layout.

17. The computer readable recording medium as claimed in claim 10, wherein the step for comparing the graphic size of the flag layer with a reference size to determine the identified rule comprises:
comparing the graphic size of the flag layer with a reference size;
if the graphic size of the flag layer is larger than the reference size, a large size identified rule is selected; and
if the graphic size of the flag layer is smaller than the reference size, a small size identified rule is selected.

18. The computer readable recording medium as claimed in claim 17, wherein the large size identified rule comprises:
setting corner graphic of the flag layer as graphic (B_BCOR);
intersecting graphic of the hth layer (MEh) in the layout and the graphic (B_BCOR), and setting a result of the intersecting as graphic (METhCA), wherein h is an integer greater than 0 and less than N+1, and N is a maximum number of layers in the layout; and
checking whether or not there is a part of the graphics not arranged at an angle of 45° in the graphic (METhCA).