JPH0834253B2 - IC pattern design device - Google Patents

Description

DETAILED DESCRIPTION [Table of Contents] Outline Industrial field of application Conventional technology Problems to be solved by the invention Means for solving the problems Action Example (1) Description of the principle of the present invention (FIGS. 1 and 2) (2) One embodiment of the present invention (FIGS. 3 to 5) Effect of the invention [Outline] Regarding an IC pattern design device, most of the calculation of the RC distribution constant of the wiring and the insertion into the restoration circuit are automated to improve the efficiency. Aiming to provide an IC pattern design device that can perform good IC pattern design, the circuit is restored from the IC design pattern, and at the time of circuit restoration, calculation of the RC distribution constant of the wiring and restoration circuit In the IC pattern designing device that requires insertion of the wiring pattern, the wiring design pattern is divided by the resistive element line segment, and a dividing means for forming the resistive element pattern in the divided portion, and a device divided by the resistive element line segment. The potential of the resistive element pattern is determined from the contact between the potential determining means for determining the potential of each divided design pattern and the contact between the resistive element pattern and the design pattern whose potential has been determined, as a distributed constant. And a distribution constant determining means for determining the RC distribution constant by calculating the capacitance as a distribution constant based on the terminal potential while restoring the resistance element of
Is provided.

[Industrial applications]

The present invention relates to an IC pattern design device, and more specifically, to an IC pattern design device.
The present invention relates to an IC pattern design device that automatically restores most of the RC distribution constant of wiring when a circuit is restored from the design pattern.

In IC development, layout design is the most important design process in LSI design, and is the task of designing the mask pattern of LSI. In this case, in order to verify the validity of the design, the circuit and circuit constants are automatically restored from the design pattern, and the circuit simulator is operated with the restored data to check the operation of the IC. In recent years, with the high integration of ICs, narrow and long wiring patterns have come to be used. Therefore, in order to perform accurate circuit simulation, the RC distribution constant of the wiring cannot be ignored and the circuit restoration device There is a need to restore the RC distribution constant of the wiring.

[Conventional technology]

In the conventional IC pattern design device, the circuit and circuit constants are automatically restored from the design pattern, but the calculation of the RC distribution constant in the restoration circuit and the insertion into the restoration circuit must be done manually every time the circuit is restored. There is. In detail, the RC network that approximates the RC distribution constant is calculated, and it is inserted into the restoration circuit when obtained.

[Problems to be Solved by the Invention]

However, in such a conventional IC pattern design device, the amount of work is large because the calculation of the RC distribution constant by hand and the insertion work into the restoration circuit must be performed every time the circuit is restored. There is a possibility that human error may be mixed in, and quick and efficient design cannot be performed.

In particular, as the integration density of ICs increases, in the circuit simulation of the conventional restoration circuit that ignores the RC distribution constant of the wiring, there are many parts that cause a non-negligible error between the result and the actual operation of the IC. Coping with manual labor becomes more difficult.

Therefore, it is an object of the present invention to provide an IC pattern designing device that can automate most of the calculation of RC distribution constants of wiring and insertion into a restoration circuit to perform efficient IC pattern designing.

[Means for solving the problem]

In order to achieve the above object, the IC pattern designing apparatus according to the present invention restores a circuit from an IC design pattern, and at the time of circuit restoration, an IC pattern that requires calculation of an IC distribution constant of wiring and insertion into a restoration circuit. In the designing device, the wiring design pattern is divided by resistive element line segments, and dividing means for forming a resistive element pattern in the divided portion, and equipotential tracing is performed on the divided design pattern by the resistive element line segments, Potential determining means for determining the potential of each divided design pattern, the terminal potential of the resistance element pattern from the contact between the resistance element pattern and the design pattern of the potential determined, and restore the resistance element as a distributed constant from this, And a distribution constant determining unit that calculates a capacitance as a distribution constant based on the terminal potential to determine the RC distribution constant.

[Action]

In the present invention, the design pattern of the wiring is divided by the resistive element line segment whose position is designated by the designer, the resistive element pattern is formed in that portion, and then the divided design pattern is subjected to equipotential tracing. The potential of the divided design pattern is determined, the terminal potential of the resistance element pattern is obtained from this, and the resistance element as a distributed constant is restored. On the other hand, the capacitance as a distribution constant is calculated based on the terminal potential, and eventually the RC distribution constant is determined.

Therefore, when the designer instructs the potential division by the resistive element line segment at the predetermined position of the design pattern when the circuit is restored,
After that, most of the time, the RC distribution constant of the wiring is automatically restored, and the efficiency of IC pattern design is greatly improved.

〔Example〕

 Hereinafter, the present invention will be described with reference to the drawings.

Description of Principle First, the principle of the present invention will be described. FIG. 1 is a diagram showing the principle of the present invention, and particularly shows a work procedure when a circuit is restored from an IC pattern.

First, the potential division by the resistance element is instructed by the line segment 2 at a predetermined position on the wiring pattern 1 where the wiring design of the IC is completed (FIG. 1 (a)). Here, the line segment 2 is formed by connecting a starting point 2a, a plurality of passing points 2b and 2c, and an ending point 2d in order. Then, the line segment 2 is widened with a minimum width that can be expressed. this is,
Line segment 2 is given a certain width, and the width is given in the smallest and unit that can be expressed by a computer. The pattern thus widened becomes a resistance element pattern 3 representing a resistance element (FIG. 1 (b)). Then, the resistance element pattern 3 is graphically subtracted from the wiring pattern 1, and the wiring pattern 1 is divided into 1a and 1b by the resistance element pattern 3 (FIG. 1 (c)). Next, the potentials of the divided wiring patterns 1a and 1b are traced to determine the respective potentials A and B of the wiring patterns 1a and 1b. After that, the contact between the resistance element pattern 3 and the wiring patterns 1a and 1b whose potentials are determined is examined (FIG. 1 (d)), and the potentials A and B of the contacted wiring patterns 1a and 1b are regarded as the terminal potential of the resistance element 4. To do. At this time, as shown in FIG. 1 (e), the resistance element pattern 3 is expressed as a resistance element 4 by the symbol of resistance, and the wiring pattern 1
The wiring patterns 1 are restored to the circuit by expressing a and 1b as terminals 5a and 5b, respectively. Then, as shown in FIG. 2, the terminal potentials of the other elements are determined, and from this, the coupling capacitances C _{1 to} C ₃ between the respective potentials are automatically calculated. As a result, the RC network that approximately expresses the RC distribution constant is restored in the restoration circuit.

In the above process, the wiring pattern 1 in FIG.
After the designer instructs the potential division by the resistive element on the line segment 2, most of the subsequent processing is automatically performed, and the RC network as shown in FIG. 2 is restored. Therefore, most of the work of calculating the RC distribution constant and the work of inserting the RC distribution constant, which were conventionally done manually, can be automated, and efficient IC pattern design can be performed.

Embodiment Next, FIGS. 3 to 5 are views showing an embodiment of the present invention based on the above-mentioned principle, which is an apparatus for performing circuit restoration, simulation, and verification.

FIG. 3 is a block diagram showing the configuration of the IC pattern designing device. In this figure, the IC pattern designing device is roughly divided into a graphic input device 11 and a verification device 12. First, the graphic input device 11 includes an auxiliary storage device 13, an auxiliary storage input / output device 14, a CPU 15, a main storage device 16, a video RAM 17,
Video controller 18, display 19, mouse input device
20, mouse 21, keyboard input device 22, keyboard 2
3. Composed of a communication input / output device 24 and a communication input / output device 25.

The auxiliary storage device 13 is the graphic input device control program execution code P1, layout pattern, and resistance element line segment data.
D1 is stored, and the CPU 15 reads the program execution code P1 into the main storage device 16 via the auxiliary storage input / output device 14 according to the instruction of the IC layout pattern designer, and draws a graphic based on the read execution code P1. Various controls of the input device 11 are performed. Further, the IC layout pattern designer uses the mouse 21 while looking at the pattern displayed on the display 19, and the layout pattern via the mouse input device 20.
The resistance element line segment can be interactively input, and similarly various instructions necessary for the pattern can be interactively input by the keyboard 23 via the keyboard input device 22. . Input layout pattern,
The resistance element line segment data D1 is held in the auxiliary storage device 13, and the pattern data D1 created in the auxiliary storage device 13 is displayed on the display 19 and is interactively corrected using the mouse 21 and the keyboard 23. Is able to. The main storage device 17 and the video control device 18 are for displaying an image on the display 19. Further, the pattern data D1 created on the auxiliary storage device 13
Is sent to the verification device 12 via the communication input / output device 24.

The verification device 12 includes a communication input / output device 25, a CPU 26, a main storage device 27, an auxiliary storage input / output device 28, a terminal input / output device 29,
It is composed of an auxiliary storage device 30, a keyboard 31, and a display 32. The pattern data D1 sent from the verification device 12 is received by the communication input / output device 25 and stored in the auxiliary storage device 30, and the CPU 26 stores the circuit restoration program execution code P2 (operation control of the present invention in the auxiliary storage device 30). Is included in the main memory device 27, and various processes for circuit restoration are performed based on the control code P2 on the main memory device 27. That is, the layout pattern of the auxiliary storage device 30 and the resistance element line data D1 are processed, and the restored circuit data D2 is created in the auxiliary storage device 30. In addition, the IC layout designer uses the resistance line segment data D1 input by the graphic input device 11.
To manually calculate the resistance value of the resistance element restored on the restoration circuit data D2 by the circuit restoration operation from the keyboard 31 to the resistance element in the restoration circuit data D2 via the terminal input / output device 29. It can be added. Further, for the simulation, the CPU 26 reads the circuit simulation program execution code P3 on the auxiliary storage device 30 into the main storage device 27, and executes the circuit simulation operation based on the control code P2 on the main storage device 27. The restored circuit data D2 is analyzed, and the analysis result D3 is created in the auxiliary storage device 30. The analysis result D3 on the auxiliary storage device 30 is displayed on the display 32, and the IC layout pattern designer can check whether or not the analysis result D3 satisfies the design requirement. Is the layout pattern and resistance element line segment data D1 on the auxiliary storage device 13 using the figure input device 11, and the corrected pattern data D1 created again on the auxiliary storage device 13 is used as the communication input / output device 24. Can be sent to the verification device 12 via. On the other hand, when the conditions are satisfied, the IC can be manufactured using the layout data on the auxiliary storage device 13.

 Next, the operation will be described.

The IC layout pattern designer creates a layout pattern using the mouse 21 while watching the pattern displayed on the display 19 of the figure input device 11, and then sends the pattern data D1 to the verification device 12 to restore the circuit, and at the same time.
The RC distribution constant is also restored to create the RC network. After that, the restored circuit is simulated, and it is verified whether the result satisfies the design requirement. If the result is not satisfied, the layout pattern is corrected again, and the process is continued until it is satisfied. And based on the filled layout data
IC is manufactured.

Here, the present embodiment is characterized by the above-mentioned circuit restoration processing, which will be described with reference to the flowchart shown in FIG. The flowchart shown in the figure is an example of manufacturing a FET.

First, in step S ₁ , the channel region of the FET is extracted.
This is because when there is a diffusion region 42 which overlaps a gate 41 formed of polysilicon as shown in FIG. The channel 43 is a portion where the gate 41 and the diffusion region 42 overlap each other, and is represented by a size partitioned as indicated by an arrow on the right side of the drawing. Next, in step S ₂ , pattern cutting by the element is performed. In the specific example, as shown in FIG. 5B, the drain region 44 and the source region 45 are formed by graphically subtracting the portion of the channel 43 from the combined portion of the diffusion region 42 and the channel 43. As for the wiring region, as shown in FIG. 5 (c), after the resistance element pattern 47 is formed by inserting and widthning the line elements for designating the resistance element into the wiring pattern 46, the resistance element pattern is formed from the wiring pattern 46.
The wiring pattern 46 is divided into 46a and 46b by subtracting 47. Step S ₂ corresponds to a block that realizes the function of the dividing unit.

Then, equipotential tracing is performed on each of the patterns divided in step S ₃ , and each potential is determined. In the specific example, as shown in FIG. 5D, all the portions including the other wiring pattern 49 connected to the drain region 44 via the contact hole 48 and the wiring pattern 51 connected to the drain electrode 44 via the contact hole 50 are all included. Consider the same potential, and let it be b. Similarly, a portion including the wiring pattern 53 connected to the source region 45 via the contact hole 52 and the wiring pattern 55 connected to the source region 45 via the contact hole 54 are all considered to be at the same potential, and this is defined as a. Step S ₃
Corresponds to a block that realizes the function of the potential determining means.

Next, in step S ₄ , the element and the wiring are connected. In a specific example, as shown in FIG. 5 (e), when there is R in the portion including the wiring pattern 49 and the wiring pattern 51, the resistance element pattern 56 is inserted and the other potential is set to c. Also,
A channel 43 is inserted between the drain region 44 and the source region 45 to make contact (connection). When this is expressed by a restoration circuit, it becomes as shown in FIG. 5 (f), and the resistance element pattern 56 is expressed by the resistance element 57. Next, in step S ₅ , the channel 43 and the gate 41 made of polysilicon are overlapped with each other to connect them to form a restoration circuit. In a specific example, as shown in FIG. 5 (g), the overlap with the channel 43 is obtained, and the potential d between the polysilicon gate 41 and the aluminum electrode 59 connected to the contact hole 58 through the contact hole 58 is determined. The circuit as shown in FIG. Next, step S ₆
The coupling capacitance between each potential is extracted with. In the specific example, as shown in FIG. 5 (i), the potential b of one wiring pattern 60 of the resistance element pattern 56 is determined, and another wiring pattern 61 and the other wiring connected to the wiring pattern 61 via the contact hole 62 are connected. The potential a of the portion including the pattern 63 and the wiring pattern 65 connected through the other contact hole 64 is determined, and the coupling capacitance is determined from these potentials a and b.
Determine and insert C _{1 to} C ₃ . This is represented by the restoration circuit shown in FIG. 5 (j). In the figure, 66 and 67 are general terms for the wiring patterns connected to the resistance element 57. Step S ₄ to S ₆ corresponds to a block that realizes the functions of the distributed constant determining means.

As described above, in this embodiment, most of the RC distribution constants of the wiring pattern can be automatically restored, and efficient IC pattern design can be performed as described above in the principle of the present invention. In particular, when the result of the restored circuit simulator is different from the expected result, the design pattern is corrected with the figure input device 11 and the circuit restoration is started again. ) The amount of work is extremely large because everything is done manually from the beginning. On the other hand, in the present embodiment, the data of the previous circuit restoration is already stored, and most of the calculation and insertion of the RC distribution constant are automated, so the above effect is obtained in the case of pattern correction. It will be remarkable.

Further, since the figure input device 11 is a method of superposing and indicating the dividing line segment by the resistance element on the IC design pattern, human visual judgment can be effectively utilized, and quick and accurate design is possible. Furthermore, since the amount of work is extremely small, the mixing of human error is drastically reduced, and even if the integration degree of IC is high, the error is extremely small.

〔The invention's effect〕

According to the present invention, when the circuit of the IC design pattern is restored, RC
Most of the distribution constant calculation work and insertion work can be performed automatically, and the efficiency of IC pattern design can be improved.

[Brief description of drawings]

1 and 2 are diagrams for explaining the principle of the present invention. FIG. 1 is a diagram showing a circuit restoration process, FIG. 2 is a diagram showing the restoration circuit, and FIGS. It is a figure which shows one Example of the IC pattern design apparatus which concerns, FIG. 3 is the whole block diagram, FIG. 4 is a flowchart which shows the process of the circuit restoration, FIG. 5 is a figure which shows the process of the circuit restoration. is there. 1, 1a, 1b ... Wiring pattern, 2 ... Line segment, 3 ... Resistor element pattern, 4 ... Resistor element, 5a, 5b ... Terminal, 11 ... Figure input device, 12 ... Verification device, 13 , 30 …… Auxiliary storage device, 14, 28 …… Auxiliary storage input / output device, 15, 26 …… CPU, 16, 27 …… Main storage device, 17 …… Video RAM, 18 …… Video control device, 19 , 32 …… Display, 20 …… Mouse input device, 21 …… Mouse, 22 …… Keyboard input device, 23,31 …… Keyboard, 24,25 …… Communication input / output device, 46,49,51 , 53, 55, 60, 61, 63, 65 to 67 …… Wiring pattern, 47, 56 …… Resistor element pattern, 48, 50, 52, 54, 58, 62, 64 …… Contact hole, 57 …… Resistor Element, step S ₂ ... dividing means, step S ₃ ... potential determining means, steps S _{4 to} S ₆ ... distribution constant determining means.

Claims (1)

[Claims] 1. An IC pattern designing apparatus, which requires a circuit to be restored from an IC design pattern, and at the time of restoring the circuit, to calculate an RC distribution constant of the wiring and to insert the wiring into the restoration circuit. Is divided by the resistive element line segment,
A dividing means for forming a resistive element pattern on the divided portion; a potential deciding means for performing equipotential tracing on the design pattern divided by the resistive element line segments to decide the potential of each divided design pattern; Then, the terminal potential of the resistance element pattern is obtained from the contact with the design pattern with the determined potential, and the resistance element as the distribution constant is restored from this, and the capacitance as the distribution constant is calculated based on the terminal potential to calculate the RC distribution constant. An IC pattern designing device characterized in that a distribution constant determining means for determining is provided.