JP2011197811A - Device and method for designing guard ring, program, and recording medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To increase the degree of freedom of the design of a guard ring in the layout of the elements and wiring of a semiconductor integrated circuit.SOLUTION: A designing device includes: a design rule storage part 11 for storing a design rule; a layout storage part 12 for storing preliminarily designated layout; a guard ring width setting part 21 for setting guard ring width suitable for the design rule as setting width; a path designation part 32 for designating the formation path of the guard ring on layout; a path recognition part 22 for recognizing a guard ring formation path based on the designation path; a guard ring formation layer storage part 13 for storing a layer list for guard ring formation; a guard ring formation layer setting part 23 for setting a layer for guard ring formation corresponding to the base layer of the recognized path; and a guard ring generation part 24 for generating the guard ring by reflecting the setting layer with the setting width on the recognition path.

Description

  The present invention relates to a guard ring design device, a guard ring design method, a program, and a recording medium for designing an arrangement of a guard ring for absorbing unnecessary carriers in the manufacture of a semiconductor integrated circuit.

  In semiconductor integrated circuits equipped with multiple circuit blocks, malfunctions such as malfunctions due to noise are prevented in order to prevent unnecessary carriers generated in each circuit block from affecting other circuit blocks and causing malfunctions. Conventionally, a guard ring has been arranged so as to surround a circuit block that may generate a fault (see, for example, Patent Document 1). The guard ring includes a diffusion layer and metal wiring for connecting the diffusion layer to a power supply voltage or ground.

  In designing a semiconductor integrated circuit, a CAD (Computer-Aided Design) system is generally used. In a CAD system, electronic circuit components that can be used for various circuits are held as cells, and a desired electronic circuit can be designed by selecting and arranging these cells and arranging metal wiring. it can. When designing an integrated circuit including a circuit block that requires a guard ring using such a CAD system, in consideration of the guard ring from the initial stage, do not place cells around the circuit block that requires the guard ring. After designing, placing all the cells and arranging all the metal wiring, the designer manually created the guard ring at the required position.

  However, because there are restrictions such as preventing the metal wiring that makes up the guard ring from crossing other wiring when creating the guard ring, if the arrangement of cells and wiring becomes complicated, manual creation of the guard ring is also required. There is a problem that it becomes complicated, and it takes a long time to create a guard ring or a wiring mistake occurs.

  In order to solve the above problem, a guard ring design device that automatically creates a guard ring around a circuit block that requires a guard ring has been proposed (see Patent Document 2).

  The guard ring design apparatus of Patent Document 2 will be briefly described. This design apparatus includes a cell list storage unit, a layout data storage unit, a cell frame recognition unit, a guard ring frame generation unit, an outer frame extraction unit, a success / failure determination unit, and a chip layout output unit. The cell list storage unit stores a list of cells, and the layout data storage unit stores the layout of those cells. The cell frame recognition unit calculates the position coordinates of the frame of each cell constituting a circuit block that requires a guard ring, based on data in the cell list storage unit and the layout data storage unit. The guard ring frame generation unit adds the necessary distance and guard ring width between the guard ring and the cell frame to the position coordinates of each cell frame calculated by the cell frame recognition unit, and the position of the guard ring frame surrounding each cell frame. Calculate the coordinates. The outer frame extraction unit extracts an outer frame surrounding all of them based on the position coordinates of each guard ring frame. The success / failure determination unit determines whether or not there is an overlap between the outer frame and another cell. When there is no overlap between the outer frame extracted by the outer frame extraction unit and other cells, the chip layout output unit places the guard ring metal wiring along the outer frame at a position excluding the intersection with other wiring. Generate.

  In the guard ring design apparatus of Patent Document 2, when a designer designates a circuit block that requires a guard ring, a guard ring is automatically generated in an empty area around the area including the circuit block. Since the design device does not have a function for setting an area (prohibited area) in which a guard ring is not desired to be arranged, if there is an area in which a guard ring is not desired to be arranged around a specified circuit block, a virtual area is not included in that area. In other words, it is necessary to arrange a certain cell so that it can be recognized as an area where the guard ring cannot be arranged, and it is difficult for the designer to freely design the arrangement area of the guard ring.

  Therefore, an object of the present invention is to increase the degree of freedom in designing a guard ring in the layout of elements and wirings of a semiconductor integrated circuit.

A guard ring design device according to the present invention includes a design rule storage unit that stores design rules of each layer constituting a layout, and all elements and all wirings formed by all layers in a state before the guard ring is generated. A layout storage unit that stores the layout, and a guard ring width that has a function that determines whether or not the value input as the guard ring width conforms to the design rule, and sets a value that conforms to the design rule as the setting width A setting unit, a route designating unit for designating a route on which a guard ring should be formed on the layout as a designated route, a route recognizing unit for recognizing a guard ring formation route as a recognition route based on the designated route, and a base layer A guard ring forming layer storage unit for storing a corresponding guard ring forming layer list, and a recognition path Recognize the ground layer, select the layer for guard ring formation according to the recognized ground layer from the layer list and set it as the setting layer, and reflect the setting layer with the setting width to the recognition path And a guard ring generation unit that generates a guard ring.
Here, the “design rule” means a rule that should be observed in the layout design of cells and wirings, such as a necessary wiring width and a necessary interval in each layer constituting the layout.

Further, in the guard ring design device of Patent Document 2, when a circuit block that requires a guard ring is specified, a guard ring having a uniform width is generated around the area including the specified circuit block. It was impossible to change.
Therefore, in the guard ring design device according to the present invention, the route designation unit has a function of adding a new designated route, and the route recognition unit has a function of recognizing a new recognized route based on the new designated route, The guard ring width setting unit preferably has a function of setting a new setting width, and the guard ring generation unit preferably has a function of generating a guard ring having a new setting width in a new recognition path. Then, the designer can design the guard ring while changing the width, and the degree of freedom in designing the guard ring is further increased.

  Furthermore, in the guard ring design device according to the present invention, the cell information storage unit that stores information on the cells constituting the layout, and the guard ring width and cell information storage unit that are set by the guard ring width setting unit are stored. And a calculation unit that calculates a minimum number of contact cells per unit length required for the guard ring based on the cell information, and the guard ring generation unit includes a guard cell that includes more contact cells than the number calculated by the calculation unit. It preferably has a function of generating a ring. As a result, the number of required contact cells per unit length is automatically calculated, which makes it easier for the designer to design the guard ring including the contact cells, shortening the time required for the design, and making design mistakes. Can be reduced.

  The guard ring design method according to the present invention determines whether or not the value input as the guard ring width conforms to the design rule of each layer constituting the layout, and sets the value conforming to the design rule as the setting width. The guard ring formation path is recognized as a recognition path based on the designated path specified on the layout of all the elements and all the wirings formed by all the layers in the state before the guard ring is generated and the guard ring generation state. Path recognition step, and recognizes the underlying layer of the recognition path, and creates a guard ring forming layer corresponding to the recognized underlying layer from a preset layer list as a list of guard ring forming layers corresponding to the underlying layer A guard ring forming layer setting step to select and set as a setting layer, and And a guard ring generation step of generating a guard ring to reflect the set layer in the setting range in the route, is to design the guard ring to execute the steps.

  In the guard ring design method according to the present invention, a new guard ring width setting step for setting a new guard ring width as a new setting width separately from the guard ring width setting step, and a newly specified path separately from the specified path. Based on the new route recognition step that recognizes the guard ring formation route as a new recognition route, and a new guard ring formation that selects a layer for guard ring formation according to the underlying layer of the new recognition route from the layer list and sets it as a new setting layer And a new guard ring generation step of generating a guard ring by reflecting the new setting layer with a new setting width on the new recognition path. Then, the designer can design the guard ring while changing the width, and the degree of freedom in designing the guard ring is further increased.

  In the guard ring design method according to the present invention, the number of contact cells per unit length required for the guard ring is calculated based on the guard ring width set by the guard ring width setting unit and the cell information stored in advance. It is preferable to further include a contact cell number calculating step to generate a guard ring including the number of contact cells calculated in the contact cell number calculating step in the guard ring generating step. As a result, the number of required contact cells per unit length is automatically calculated, which makes it easier for the designer to design the guard ring including the contact cells, shortening the time required for the design, and making design mistakes. Can be reduced.

  The program according to the present invention causes a computer to function as a guard ring design device by executing the steps according to the guard ring design method described above.

  The recording medium according to the present invention is a computer-readable recording medium on which the above program is recorded.

  According to the guard ring design device and the design method of the present invention, by setting the width of the guard ring and specifying the formation path, the path conforming to the design rule is recognized based on the specified path, and the recognition is performed. A layer necessary for forming a guard ring from the underlying layer of the route is set, and a guard ring reflecting the layer is generated in the recognition route with a set width, so it is easy to design a guard ring with a high degree of freedom. It is possible.

  By incorporating the program of the present invention for executing the guard ring design method of the present invention into a computer, the computer can function as the guard ring design apparatus of the present invention.

  By reading a recording medium recording the program of the present invention with a computer, the program of the present invention can be incorporated into the computer, and the computer can function as the guard ring designing apparatus of the present invention.

1 is a block diagram schematically showing a first embodiment. FIG. It is a flowchart which shows the guard ring design procedure in the Example. It is a block diagram which shows a 2nd Example schematically. It is a flowchart which shows the guard ring design procedure in the Example. It is a figure of the layout screen for demonstrating the guard ring production | generation process on a layout. FIG. 6 is a layout screen showing a continuation of FIG. 5. FIG. 7 is a layout screen showing a continuation of FIG. 6.

A first embodiment of the guard ring design apparatus will be described below with reference to FIGS.
First, the configuration of an embodiment will be described with reference to FIG. The guard ring design apparatus according to this embodiment is included in a CAD system and includes a storage unit 1, a processing unit 2, and an interface unit 3. The storage unit 1, the processing unit 2, and the interface unit 3 are each configured by elements that constitute a PC (personal computer) that operates the CAD system. The storage unit 1 is configured by a partial area of a storage device built in the PC. The processing unit is configured by a CPU (Central Processing Unit) of the PC and a program. The interface unit 3 is a means for a designer to operate the design apparatus and confirm information from the design apparatus. Specifically, the interface unit 3 is realized by a keyboard, a mouse, and a monitor connected to a PC.

  The storage unit 1 includes a design rule storage unit 11, a layout storage unit 12, a guard ring formation layer storage unit 13, and a guard ring post-generation layout storage unit 14. The design rule storage unit 11 stores design rules in the layout design of cells and wiring, such as necessary wiring width and necessary spacing in each layer constituting the layout. The layout storage unit 12 stores, as layout data, the layout of each cell or wiring formation process designed in advance. The guard ring forming layer storage unit 13 stores a list of layers necessary for well demarcation, ion implantation, and metal patterning for forming a guard ring corresponding to the underlying layer of the guard ring forming region. Yes. The post guard ring generation layout storage unit 14 is an area for storing layout data after a guard ring is generated by a guard ring generation unit described later.

  The processing unit 2 includes a guard ring width setting unit 21, a path recognition unit 22, a guard ring formation layer setting unit 23, and a guard ring generation unit 24. The interface unit 3 includes a width input unit 31, a route specifying unit 32, and a layout display unit 33. The width input unit 31 is realized by a keyboard, the route specifying unit 32 is realized by a mouse, and the layout display unit 33 is a PC. Realized by a monitor.

  When the guard ring width setting unit 21 determines whether or not the guard ring width input by the designer via the width setting unit 31 conforms to the design rule stored in the design rule 11, Is set as the width of the guard ring forming the width. Hereinafter, the width set by the guard ring width setting unit 21 is referred to as “set width”.

  The route recognition unit 22 displays the layout before guard ring design on the layout display unit 33 and recognizes the guard ring formation route designated by the designer via the route designation unit 32 on the layout. Hereinafter, the route recognized by the route recognition unit 22 is referred to as a “recognized route”.

  The guard ring formation layer setting unit 23 recognizes the base layer of the path recognized by the path recognition unit 22 and executes a process necessary for forming a guard ring in the region formed by the base layer. All necessary layers are determined from the layer list of the guard ring formation layer storage unit 13 and set as guard ring formation layers. Hereinafter, a layer set by the guard ring formation layer setting unit 23 is referred to as a “setting layer”.

  The guard ring generation unit 24 generates a guard ring with a set width in the recognition path on the layout. The guard ring is generated in a form reflecting the setting layer, and a region defined for ion implantation, a well region formed by diffusion, and a metal wiring formed in an upper layer are generated for each layer. The layout after the guard ring is generated is displayed on the layout display unit 33 and the data is stored in the guard ring generated layout storage unit 14.

Next, an example of a guard ring design procedure by the guard ring design apparatus of this embodiment will be described with reference to FIGS.
First, a layout image before guard ring design created in advance is displayed on the layout display section 33 (step S1, FIG. 5). The designer inputs the width of the metal wiring of the guard ring to be arranged from the width input unit 31 (step S2). The guard ring width setting unit 21 determines whether or not the input width satisfies the minimum wiring width defined in the design rule (step S3), and if not, prompts the designer to input the width again. When the minimum width is satisfied, the width is set as the guard ring width.

  The designer designates a route on which the guard ring is to be arranged on the layout displayed on the layout display unit 33 by the route designation unit 32 (step S5, FIG. 6). The route recognition unit 22 recognizes the route designated by the designer as a guard ring formation route (step S6).

The guard ring formation layer setting unit 23 recognizes the layer that is the basis of the recognition path recognized by the path recognition unit 22 (step S7). Further, the guard ring formation layer setting unit 23 calculates and sets the layers necessary for forming the guard ring in the region formed by the base layer from the layer list of the guard ring formation layer storage unit 13 (step). S8). Here, for example, when the recognition path is on the layer of the N well region,
Well defining layer: Well 1 layer Ion implantation layer: N plus implantation layer Metal wiring layer: Metal 1 formation layer All layers used for the process necessary for forming the guard ring Is set.

  When the guard ring forming layer is set, the guard ring generating unit 24 generates a guard ring on the layout based on the set layer, the recognition path, and the setting width (step S9, FIG. 7). The layout display section 33 displays the layout screen after the guard ring is generated, and the data is stored in the guard ring generated layout storage section 14. On the layout screen, the guard ring is generated in a form that reflects the setting layer, and is displayed in a state in which color coding or the like is identified for each layer.

  In this embodiment, it is possible to further design a guard ring to be arranged (step S10). When an additional guard ring is designed, a new guard ring width can be input (step S11). If the guard ring width is not changed, the procedure after step S5 is performed. If the guard ring width is changed, the procedure returns to step S2, and the designer inputs a new guard ring width, and the procedure after step S3 is performed. .

  In this way, by providing a function for adding a guard ring having a new width, for example, in a route surrounding a circuit block that requires a guard ring, the route is not designated by a single route designation. If different widths are set and specified in a plurality of times, it is possible to design a guard ring with different widths depending on the location, and a guard ring design with a high degree of freedom is possible.

Next, a second embodiment of the guard ring design apparatus will be described with reference to FIGS.
The guard ring device of this embodiment is different from the guard ring device of the first embodiment in that the guard ring to be designed includes a contact cell. That is, the processing unit 2a of the design apparatus of this embodiment includes a width setting / calculating unit 25 instead of the guard ring width setting unit 21 of the first embodiment. In addition to the guard ring width setting function similar to the guard ring width setting unit 21, the width setting / calculation unit 25 has a function of calculating the number of contact cells per unit length necessary for the guard ring to be arranged. Since other configurations are the same as those in the first embodiment, detailed description thereof is omitted.

  The width setting / calculation unit 25 will be described. The design rule storage unit 11 stores contact space, overlap amount, power supply capacity, etc., and the width setting unit / calculation unit 25 reads the information after setting the guard ring width and is necessary for the guard ring. Calculate the number of (optimal) contact cells per unit length. The design rule storage unit 11 also constitutes a cell information storage unit.

A guard ring design procedure by the design apparatus of this embodiment will be described with reference to FIG. A detailed description of the same part of the design procedure as that of the first embodiment is omitted.
The layout is displayed on the layout display unit 33 (step S21), and the designer inputs the guard ring width (step S22). The width setting / arithmetic unit 25 confirms the design rule for the input width (step S23) and sets the width (step S24), and then reads the set width and the contact space read from the design rule storage unit 11 and the overlap. The number per unit length required for the contact cell is calculated based on the information such as the quantity and the power supply capacity (step S25).

  Thereafter, after the route designation by the designer (step S26), the route recognition unit 22 recognizes the designated route (step S27), and the guard ring formation layer setting unit 23 guards the guard ring corresponding to the underlying layer of the recognized route. A forming layer is set (steps S28 and S29). The guard ring generating unit 24 generates a guard ring having a set width in the recognition path on the layout by reflecting the set layer (step S30). The guard ring generated here includes the number of contact cells per unit length calculated by the width setting / calculating unit 25. Note that the arrangement position and interval of the contact cells may be automatically set and arranged by the guard ring generation unit 24, or the designer may have more than the number of contact cells per unit length. The arrangement position may be designated.

  Also in this embodiment, it is possible to further design the guard ring to be arranged (step S31). When an additional guard ring is designed, a new guard ring width can be input (step S32).

DESCRIPTION OF SYMBOLS 1 Memory | storage part 2 Processing part 3 Interface part 11 Design rule memory | storage part 12 Layout memory | storage part 13 Guard ring formation layer memory | storage part 14 Guard ring generation layout memory | storage part 21 Guard ring width setting part 22 Path | route recognition part 23 Guard ring formation layer Setting unit 24 Guard ring generation unit 31 Width input unit 32 Route specification unit 33 Layout display unit

JP 2006-286800 A Japanese Patent No. 3117908

Claims (8)

A design rule storage unit for storing design rules of each layer constituting the layout;
A layout storage unit for storing a layout of all elements and all wirings formed by all layers in a state before generating the guard ring;
A guard ring width setting unit that has a function of determining whether a value input as a guard ring width conforms to the design rule, and sets a value that conforms to the design rule as a setting width;
A route designating unit for designating a route for forming a guard ring on the layout as a designated route;
A route recognition unit that recognizes a guard ring formation route as a recognition route based on the designated route;
A guard ring forming layer storage unit for storing a guard ring forming layer list corresponding to the underlying layer;
A guard ring forming layer setting unit that recognizes a base layer of the recognition path, selects a layer for forming a guard ring corresponding to the recognized base layer from the layer list, and sets the layer as a setting layer;
A guard ring design device comprising: a guard ring generation unit that generates a guard ring by reflecting the setting layer with the setting width on the recognition path. The route specifying unit has a function of adding a new specified route,
The route recognition unit has a function of recognizing a new recognition route based on the new designated route,
The guard ring width setting unit has a function of setting a new setting width,
The guard ring design apparatus according to claim 1, wherein the guard ring generation unit has a function of generating a guard ring having a new set width in the new recognition path. A cell information storage unit for storing information of cells constituting the layout;
An arithmetic unit for calculating the number of contact cells per unit length necessary for the guard ring based on the guard ring width set by the guard ring width setting unit and the cell information stored in the cell information storage unit; In addition,
The guard ring design apparatus according to claim 1, wherein the guard ring generation unit has a function of generating a guard ring including a number of contact cells calculated by the calculation unit. A guard ring width setting step of determining whether or not a value input as a width of the guard ring conforms to a design rule of each layer constituting the layout, and setting a value conforming to the design rule as a setting width;
A path recognition step for recognizing a guard ring formation path as a recognition path based on a designated path specified on a layout of all elements and all wirings formed by all layers in a state before generating the guard ring;
Recognize the underlying layer of the recognition path, and select a guard ring forming layer corresponding to the recognized underlying layer from a list of layers set in advance as a list of guard ring forming layers corresponding to the underlying layer as a setting layer. A guard ring forming layer setting step to be set;
A guard ring generation step of generating a guard ring by reflecting the setting layer with the setting width on the recognition path, and performing each step to design the guard ring. A new guard ring width setting step for setting a new guard ring width as a new setting width separately from the guard ring width setting step,
A new route recognition step for recognizing a guard ring formation route as a new recognition route based on a newly designated route separately from the designated route;
A layer setting step for forming a new guard ring for selecting a layer for forming a guard ring corresponding to the base layer of the new recognition path from the layer list and setting it as a new setting layer;
The guard ring design method according to claim 4, further comprising: a new guard ring generation step of generating a guard ring by reflecting the new setting layer with the new setting width in the new recognition path. A contact cell number calculation step for calculating the number of contact cells per unit length required for the guard ring based on the guard ring width set by the guard ring width setting unit and the cell information stored in advance; ,
The guard ring design method according to claim 5, wherein a guard ring including at least the number of contact cells calculated in the contact cell number calculation step is generated in the guard ring generation step.   The program for functioning a computer as a guard ring design apparatus by performing each step which concerns on the guard ring design method as described in any one of Claims 4-6.   A computer-readable recording medium on which the program according to claim 7 is recorded.

Images