JP2013242427A - Method and program for controlling opc processing, and method for manufacturing mask - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a technique capable of easily executing OPC (Optical Proximity Correction) processing for a bent gate.SOLUTION: In a method for controlling a workstation executing OPC processing, the workstation determines an oblique line of a bent gate of a layer LA whose length is to be measured contained in a mask layout data, and generates a first rectangle figure data A in which the determined oblique line is regarded as a diagonal line. The workstation generates a layer LB to be corrected that is composed of rectangle figures, by performing cutout of the first rectangle figure data A from the layer LA whose length is to be measured. The workstation generates mask layout data after correction by performing synthesis processing or the cutout processing on a second rectangle figure data B for the layer LB to be corrected.

Description

  The present invention relates to an OPC (Optical Proximity Correction) process control method, a program, and a mask manufacturing method for correcting mask layout data. For example, the present invention relates to a technique for correcting a vent gate by OPC process.

  As semiconductors become finer, OPC processing is performed to correct a pattern in consideration of the optical proximity effect when creating mask layout data. In the OPC process, for example, even if the pattern is a square pattern in the layout, there is an effect such as rounding the corners when exposed and etched, and the pattern is corrected to remove this effect.

  The following Patent Document 1 (Japanese Patent Laid-Open No. 2003-315976) discloses that even when a fine pattern is generated when the pattern is divided into rectangular patterns, the fine pattern is properly exposed on the exposure original plate by electron beam exposure. A technique for forming a pattern is disclosed. In Patent Literature 1, a minute pattern is extracted, and the minimum dimension of the extracted minute pattern is thickened to such an extent that the optical proximity effect does not occur.

  In recent years, gates (bent gates) designed with diagonal lines have been used to reduce the cell area. The following Patent Document 2 (Japanese Patent Laid-Open No. 2001-77199) discloses a transistor configured with a vent gate. Therefore, it is necessary to apply the OPC process to the bent gate.

JP 2003-315976 A JP 2001-77199 A

  However, when an OPC process is applied to a bent gate, for example, when a figure is laid out at an angle of 45 degrees, the side where the angle is 0 degrees or 90 degrees and the edge of the 45 degrees is connected to the bent gate, etc. There are problems such as the occurrence of wedge-shaped acute patterns. Further, if a figure having a 45-degree side is replaced with a set of rectangular figures having a short side, the amount of figures increases, and the drawing time of mask figure data becomes long. Therefore, there is a need for a technique that can easily execute the OPC process for the bent gate.

  Other problems and novel features will become apparent from the description of the specification and the accompanying drawings.

  According to one embodiment, a method for controlling an information processing device that performs OPC processing is provided. The processor identifies a bent line of the bent gate included in the mask layout data, and generates first rectangular figure data having the specified diagonal line as a diagonal line. The processor obtains correction target data including a rectangular figure by performing a die cutting process on the first rectangular figure data from the pattern data including the bent gate. The processor generates corrected mask layout data by synthesizing or punching the second rectangular figure data with respect to the correction target data.

  According to the above-described embodiment, correction processing based on a rectangular figure is performed, and an acute pattern can be prevented and mask drawing data drawing time can be shortened.

FIG. 3 is a block diagram of each apparatus constituting the mask manufacturing system in the first embodiment. It is a figure which shows the relationship between vent length and the width of a vent gate. 3 is a flowchart illustrating an OPC process according to the first embodiment. 6 is a diagram illustrating a process of correcting mask layout data by the OPC process according to the first embodiment. FIG. It is a figure which shows the example of correction | amendment of the mask layout data containing a bent gate. It is a figure which shows the example of correction | amendment of the mask layout data containing a bent gate. The figure which plotted the difference of the gate dimension of a bent gate and the gate dimension of a normal gate according to the sizing amount is shown. It is a figure which shows distribution of the gate dimension of the vent gate for every vent length at the time of performing lithography and dry etching using the mask which performed the OPC process. It is a figure which shows the example of correction | amendment when vent length is longer than a gate dimension. It is a figure which shows the example of correction | amendment when vent length is longer than a gate dimension. It is a figure which shows the example which interpolates the level | step difference which arises when an oblique line is formed with a rectangular figure.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following description, the same parts are denoted by the same reference numerals. Their names and functions are also the same. Therefore, detailed description thereof will not be repeated.

<Configuration of 1 Embodiment 1>
FIG. 1 is a block diagram of each apparatus constituting the mask manufacturing system in the first embodiment.

  As shown in FIG. 1, the mask manufacturing system includes a plurality of terminals (terminal 71 and terminal 72 in the example shown in FIG. 1), a workstation 50, and a mask manufacturing apparatus 60, and each apparatus is connected by a network. Has been.

  The terminal 71 and the terminal 72 are computer systems including an MCU (Micro Controller Unit), a RAM (Random Access Memory), a display, and the like (not shown), and are connected to the workstation 50 through a network. The terminals 71 and 72 function as input terminals for the workstation 50. The terminal 71 and the terminal 72 are provided with an input device, receive a user input for operating the workstation 50, and transmit the received operation to the workstation 50 through the network. The terminals 71 and 72 receive the response from the workstation 50 and display the editing result of the mask layout data on the display.

  The workstation 50 includes an exposure data creation unit 51 and a mask layout data storage unit 52. The workstation 50 includes an MCU, RAM, and the like (not shown), and executes OPC processing according to control by a program.

  The mask layout data storage unit 52 stores mask layout data indicating an exposure pattern.

  The exposure data creation unit 51 accepts an operation from the terminal 71 or the like input to the workstation 50 through the network, and creates mask layout data by executing OPC processing on the mask layout data. The function of the exposure data creation unit 51 is exhibited when the workstation 50 executes a CAD (computer aided design) program for generating a mask layout pattern.

  The mask manufacturing apparatus 60 includes an exposure unit 63 that emits light in a wavelength region suitable for mask formation, an MCU (not shown), a RAM, and the like, and drives the exposure unit 63 based on mask layout data according to control by a program. To manufacture a mask. The mask manufacturing apparatus 60 can create mask layout data in the same manner as the workstation 50. The mask manufacturing apparatus 60 is connected to the workstation 50 via a network, and receives mask layout data created by the workstation 50 from the workstation 50 via the network.

  The mask manufacturing apparatus 60 includes an exposure data creation unit 61 and a mask layout data storage unit 62.

  The mask layout data storage unit 62 stores mask layout data indicating an exposure pattern.

  The exposure data creation unit 61 accepts a user operation input to the mask manufacturing apparatus 60 and creates mask layout data by executing an OPC process on the mask layout data. The function of the exposure data creation unit 61 is exhibited when the mask manufacturing apparatus 60 executes a CAD program for generating a mask layout pattern.

<2 Relationship between vent length and vent gate width>
Here, in order to compare the case where the OPC process according to the first embodiment is performed with the case where the OPC process is not performed, a relationship between the vent length and the width of the vent gate when the OPC process according to the first embodiment is not applied will be described.

<2.1 Increase in gate line width at bent gate>
FIG. 2 is a diagram illustrating the relationship between the vent length and the width of the vent gate.

FIG. 2A shows a CAD layout of the bent gate.
As shown in FIG. 2A, the pattern 31 is adjacent to the contact 32 and the contact 33, and has a vent gate 24. The pattern 34 also has a vent gate 24. The pattern 35 consists of only a rectangular figure and has a normal gate. In FIG. 2A, the gate width of the normal gate is indicated by a normal gate width 21. The gate width of the bent gate is indicated by the gate width 22 of the bent gate. Here, the vent length indicates the size of the oblique line portion of the vent gate, which is indicated by the vent length 23 shown in FIG. 2A, and represents the horizontal length of the oblique line portion of the gate.

In this way, when forming a bent gate, in the CAD layout, there are a side whose angle is horizontal (0 degrees), a side whose vertical direction is 90 degrees, and a side whose angle is 45 degrees forming the bent gate. Mixed. When an attempt is made to form a mask based on such a CAD layout, the dimensions of a normal gate formed at a side of 0 or 90 degrees and the dimensions of a bent gate formed at a side of 45 degrees are aligned. There is a problem that is difficult. Specifically, FIG. 2 (B) is a diagram showing the dimensions of the vent gate when the vent length is changed.
FIG. 2B shows the dimensions of the vent gate when the dimension of the gate is L (μm) and the vent length is changed from 0 μm to 0.16 μm. As shown in FIG. 2B, the dimensions of the vent gate are thicker from about 0.005 μm to about 0.03 μm compared to a normal gate (vent length = 0 μm).

FIG. 2C is a diagram in which the CAD layout and the dimensions of the gate lines are overlapped.
As shown in FIG. 2C, the gate line 10 is formed thicker than the design value with respect to the design layout 9. The dimensions of the gate line 10 can be predicted by optical simulation using the design layout 9.

<2.2 Malfunctions associated with the occurrence of acute patterns in bent gates>
Further, when the OPC process of the first embodiment is not applied, for example, the OPC process is executed based on the positional relationship of the rectangular figure. By executing such an OPC process in the CAD layout, a wedge-shaped acute pattern is generated at the joint portion between the 0-degree or 90-degree side and the oblique 45-degree side or a part of the 45-degree side. A malfunction occurs. Even if an OPC process is executed by replacing a figure including a 45-degree oblique side with a small rectangular figure in order to suppress the occurrence of an acute pattern, the figure amount increases, for example, the drawing time increases and the OPC process takes a long time. There is a problem of becoming. In order to suppress an increase in drawing time, it is also assumed that the OPC process is executed by preparing in advance a diagonal graphic template corresponding to a layout graphic having a 45 ° diagonal side.

  However, in any of the above methods, when the OPC process of the first embodiment is not applied, there is a problem that it is difficult to align the gate dimensions of the bent gate portion and the normal gate. On the other hand, the OPC process in the first embodiment prevents the occurrence of an acute pattern and shortens the drawing time of mask layout data in a CAD layout or the like. Hereinafter, the contents of the OPC process in the first embodiment will be described in detail.

<3 Operation in Embodiment 1>
Details of the OPC process in the first embodiment will be described with reference to FIGS. 3 and 4.

  FIG. 3 is a flowchart showing the OPC process of the first embodiment. FIG. 4 is a diagram illustrating a process of correcting mask layout data by the OPC process according to the first embodiment. In the first embodiment, the OPC process will be described as the operation of the workstation 50.

  As shown in FIG. 3, the workstation 50 reads the mask layout data stored in the mask layout data storage unit 52, and in the figure shown in the length measurement target layer LA that is pattern data including the bent gate, Identify the diagonal line. Specifically, the workstation 50 extracts a side between inner angles of 135 degrees and 225 degrees in the length measurement target layer LA, and identifies the extracted side as an oblique line (step S31). The workstation 50 generates first rectangular graphic data A with the diagonal line identified in step S31 as a diagonal line (step S33). The processing results of steps S31 and S33 are shown in FIG.

  The workstation 50 generates the correction target layer LB by performing the die cutting process on the first rectangular graphic data A from the length measurement target layer LA (step S35 in FIG. 3). The processing result of step S35 is shown in FIG.

  The workstation 50 is a side that is sandwiched between 90 ° and 270 ° in the graphic shown in the correction target layer LB, overlaps with the first rectangular graphic data A, and further has a side length. Edges whose length L is within a predetermined range (P1 <L ≦ P2 is satisfied, L) are extracted (step S37). In FIG. 4C, the sides extracted in step S37 are highlighted in bold.

  The workstation 50 generates the second rectangular figure data B with the side extracted in step S37 as one side and the length of the side perpendicular to the side as a variable (sizing amount P3). If the sizing amount P3 is a positive value, the workstation 50 generates the second rectangular figure data B outside the correction target layer LB. If the sizing amount P3 is negative, the workstation 50 generates a second inner side of the correction target layer LB. The second rectangular figure data B is generated. If the sizing amount P3 is a positive value, the workstation 50 performs processing for combining the correction target layer LB and the second rectangular graphic data B to generate corrected mask layout data (D1 in FIG. 4). )). If the sizing amount P3 is a negative value, the workstation 50 performs the die cutting process on the second rectangular figure data B from the correction target layer LB to generate corrected mask layout data (FIG. 4 (D2)). (Step S39).

  In step S39, the workstation 50 predicts the dimensions of the bent gate portion by optical simulation or the like based on the mask layout data corresponding to the sizing amount P3 as a variable when the exposure is performed using the mask according to the mask layout data. (Step S41). In addition, after actually manufacturing a mask according to the mask layout data and performing lithography and dry etching using this mask, the gate dimensions may be measured and acquired.

  The workstation 50 determines the value of the sizing amount P3 in which the dimension of the bent gate portion acquired in step S41 according to each variable sizing amount P3 is substantially the same as the normal gate dimension of the length measurement target layer LA. Is specified (step S43).

  The workstation 50 generates mask layout data by the process of step S39 according to the value of the sizing amount P3 specified in step S43 (step S45).

Here, a correction example of the mask layout data will be described with reference to FIGS. 5 and 6.
FIG. 5 is a diagram illustrating a correction example of mask layout data including a bent gate.

  FIG. 5A shows graphic data including a 45 ° diagonal graphic. The workstation 50 specifies, as an oblique line, a side between the vertex 2 of the convex portion of the vent portion and the vertex 3 of the concave portion with respect to the graphic 1 showing the graphic including the vent gate (step S31 in FIG. 3). . The workstation 50 generates first rectangular graphic data having the specified diagonal line as a diagonal line, and performs a die cutting process from the graphic 1. FIG. 5B is a diagram illustrating the correction target layer after the die cutting process. In FIG. 5B, the sides having overlap between the first rectangular graphic data used for the die cutting process and the graphic 1 are a side g and a side g ′. The workstation 50 generates second rectangular graphic data in which the side of the side g ′ including the vertex 2 of the convex portion of the bent portion is one side. FIG. 5C is a diagram showing corrected mask layout data. The workstation 50 uses the sizing amount indicating the length of the side parallel to the side g as a variable to generate second rectangular graphic data. In FIG. 5C, the sizing amount is indicated by “a”.

Here, a method for specifying the sizing amount “a” will be described in detail.
FIG. 6 is a diagram illustrating a correction example of mask layout data including a bent gate.

  FIG. 6A shows a vent gate having a gate size 7 and a vent length 8. FIG. 6B is a diagram showing the correction target layer generated by performing the die cutting process using the first rectangular graphic data as described above. FIG. 6C shows the corrected mask layout data when the sizing amount is positive, and FIG. 6D shows the corrected mask layout data when the sizing amount is negative. . In FIGS. 6C and 6D, the sizing amount is shown as “a”. The workstation 50 uses the value of “a” as a variable and changes the value of “a” to generate mask layout data. A mask is created according to the layout generated in this way, and lithography and dry etching are performed using the created mask. The dimensions of the bent gate portion on the wafer formed in this way are acquired for each layout (step S41 in FIG. 3). The difference between the obtained dimension of the bent gate portion and the gate dimension of the normal gate is plotted according to the value of “a”.

  FIG. 7 is a diagram in which the difference between the gate size of the bent gate and the gate size of the normal gate is plotted according to the sizing amount. Using this plot, the value of “a” is specified in which the gate dimension of the bent gate is substantially the same as the gate dimension of the normal gate (the difference in gate dimension is substantially zero).

  Based on the sizing amount “a” thus specified, the OPC process described in the above embodiment is performed to generate mask layout data. The mask manufacturing apparatus 60 acquires the corrected mask layout data generated as described above and stores it in the mask layout data storage unit 62. The mask manufacturing apparatus 60 manufactures a mask based on the corrected mask layout data. Lithography and dry etching are performed using this mask.

  FIG. 8 is a diagram showing the distribution of the gate dimensions of the vent gate for each vent length when lithography and dry etching are performed using a mask that has been subjected to the OPC process. As shown in FIG. 8, the gate dimensions are within a certain range equivalent to the gate dimensions of a normal gate.

  As described above, according to the first embodiment, the OPC process can be performed on the graphic layout including the bent line of the bent gate by the process such as the synthesis of the rectangular graphic. Drawing time can be shortened. In addition, the gate size of the bent gate portion can be matched with the gate size of a normal gate.

<4. Embodiment 2>
Next, another embodiment will be described with reference to the drawings.

FIG. 9 is a diagram illustrating a correction example when the vent length is longer than the gate dimension.
FIG. 9A shows a vent gate. As shown in FIG. 9A, the vent length is longer than the gate dimension. FIG. 9B is a diagram illustrating a process of generating a correction target layer and synthesizing rectangular graphic data. As shown in FIG. 9B, the workstation 50 identifies the bent line of the bent gate (step S31 in FIG. 3), and corrects the first rectangular figure data by performing a die cutting process from the measurement target layer. After the target layer is generated (step S35 in FIG. 3), the figures are separated. In this case, as shown in FIG. 9C, the workstation 50 places a square having a side length of “b” in the middle of the separated graphics, and merges the graphics. At this time, the length “b” of one side of the square may be determined according to the value of the sizing amount “a” that affects the size of the second rectangular figure data.

  Here, the workstation 50 uses the sizing amount “a” and the length “b” of one side of the square as variables, and generates mask layout data according to the values of the variables. The workstation 50 acquires the gate dimensions of the vent gate on the wafer by optical simulation or the like for each mask layout data. As a result, the values of the variables “a” and “b” at which the gate dimensions of the bent gate are approximately equal to the gate dimensions of the normal gate can be acquired.

  Note that the center (square placement position) of a square having a length of “b” on one side can be calculated based on the position of the vertex of the diagonal line when it is specified as the diagonal line in step S31.

FIG. 10 is a diagram illustrating a correction example when the vent length is longer than the gate dimension.
As shown in FIG. 10 (A), a square may be arranged between the separated figures, and as shown in FIG. 10 (B), the lengths of the two sides are “c” and “d”. A rectangle may be arranged.

  As described above, the squares or rectangles are described as being arranged between the separated figures, but a plurality of squares or rectangles may be arranged. For example, for a sufficiently long diagonal wiring, after a correction target layer is generated in step S35 and the figure is separated, squares or rectangles may be repeatedly arranged to form a continuous figure.

<5 Embodiment 3>
Next, another embodiment will be described with reference to the drawings.

  FIG. 11 is a diagram illustrating an example of interpolating a step generated when a diagonal line is formed by a rectangular figure.

  In the second embodiment, it has been described that a square or a rectangle is arranged after a correction target layer is generated and a figure is separated in step S35. As a result, as shown in FIG. 11A, as a result of supplementing the oblique line portion with a rectangular figure, a step is generated. When the step portion is divided into a plurality of rectangles and the influence on the gate size is small, the step may be filled. As shown in FIG. 11B, the workstation 50 can fill the steps step by step by repeating the process of combining the second rectangular graphic data with the correction target layer.

  Thereby, the drawing time of the mask layout data by the workstation 50 can be shortened.

  Each embodiment has been described above, but it goes without saying that these embodiments may be combined.

  As mentioned above, the invention made by the present inventor has been specifically described based on the embodiment. However, the present invention is not limited to the embodiment, and various modifications can be made without departing from the scope of the invention. Needless to say.

  1 figure, 2 convex vertex, 3 concave vertex, 9 design layout, 10 gate line, 21 gate width, 22 vent gate gate width, 23 vent length, 24 vent gate, 31 pattern, 32 contact, 33 contact, 34 patterns, 35 patterns, 50 workstations, 51 exposure data creation unit, 52 mask layout data storage unit, 60 mask manufacturing apparatus, 61 exposure data creation unit, 62 mask layout data storage unit, 63 exposure unit, 71 terminal, 72 terminal A, first rectangular graphic data, B second rectangular graphic data, LA measurement target layer, LB correction target layer.

Claims (7)

A method for controlling an information processing apparatus that performs an OPC process for correcting mask layout data, the information processing apparatus including a processor and a memory for storing the mask layout data And
The method
The processor specifies a bent line of the bent gate included in the mask layout data, and generates first rectangular graphic data having the specified diagonal line as a diagonal line; and
The processor obtains correction target data including a rectangular figure by performing a die cutting process on the generated first rectangular figure data from pattern data including the bent gate; and
The processor synthesizes the second rectangular graphic data having one side that overlaps the first rectangular graphic data and the correction target data with the correction target data, or the correction target data Generating a corrected mask layout data by performing a die cutting process from
A method for controlling an information processing apparatus. In the step of generating the corrected mask layout data, the processor acquires a dimension of a gate formed by exposure using a mask according to the mask layout data;
The processor generates the second rectangular graphic data using a length of a side perpendicular to the overlapping side as a variable, and generates corrected mask layout data according to the value of the variable, respectively;
For each corrected mask layout data generated according to the value of the variable, the processor acquires the dimension of the bent gate to be formed by the step, and the dimension of the bent gate acquired for the value of each variable is Identifying the value of a variable that is substantially the same as the dimensions of a normal gate,
The method for controlling an information processing apparatus according to claim 1. In the step of generating the first rectangular figure data,
The processor specifies, as the diagonal line, a side sandwiched between a 135-degree angle and a 225-degree angle among the internal angles of the figure constituting the bent gate.
The method for controlling an information processing apparatus according to claim 1. In the step of generating the corrected mask layout data,
The processor is a side sandwiched between an angle of 90 degrees and an angle of 270 degrees of the graphic shown in the correction target data, and has an overlap with the first rectangular graphic data, and has a predetermined range. Extracting a length edge; and
Generating the second rectangular figure data with the extracted side having a predetermined length as one side,
The method for controlling an information processing apparatus according to claim 1. In the step of generating the corrected mask layout data,
A step of interpolating the rectangular figure data between the separated rectangular figures when the rectangular figure is separated by performing a die cutting process on the first rectangular figure data from the pattern data including the bent gate; Including,
The method for controlling an information processing apparatus according to claim 1. A program for controlling an information processing apparatus that executes an OPC process for correcting mask layout data, the information processing apparatus including a processor and a memory for storing the mask layout data And
The program is stored in the processor.
Specifying the diagonal line of the bent gate included in the mask layout data and generating first rectangular graphic data having the specified diagonal line as a diagonal line; and
Generating correction target data including a rectangular figure by performing a die cutting process on the generated first rectangular figure data from pattern data including the bent gate; and
The second rectangular graphic data having one side that overlaps the first rectangular graphic data and the correction target data is combined with the correction target data, or the die cutting process is performed from the correction target data. Generating corrected mask layout data by performing
program. A mask manufacturing method in a mask manufacturing system in which an information processing apparatus executes an OPC process for correcting mask layout data, and the mask manufacturing apparatus manufactures a mask based on the corrected mask layout data, the information processing apparatus Includes a first processor and a memory for storing the mask layout data, and the mask manufacturing apparatus includes a second processor and an exposure unit,
The mask manufacturing method includes:
The first processor specifying a diagonal line of the bent gate included in the mask layout data, and generating first rectangular figure data having the specified diagonal line as a diagonal line; and
The first processor obtains correction target data consisting of a rectangular figure by performing a die cutting process on the generated first rectangular figure data from the pattern data including the bent gate; and
The first processor synthesizes the second rectangular graphic data having one side that overlaps the first rectangular graphic data and the correction target data with the correction target data, or Generating a mask layout data after correction by performing a die cutting process from the correction target data, and storing the mask layout data in the memory;
A second processor of the mask manufacturing apparatus acquires the corrected mask layout data from the memory and manufactures a mask by controlling exposure by the exposure unit according to the corrected layout data; including,
Mask manufacturing method.

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