JP2001013669A - Mask drawing data preparing method, preparing device and memory medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the efficiency of pattern matching, to decrease the number of times of calculation processing of correction shapes by lithography simulation and to improve the processing speed for correction of an optical proximity effect by executing a pattern matching after conversion of a grid of input data to a larger grid. SOLUTION: The points or regions A to C for correction are extracted relating to input data, (a). Firstly, the pattern layout of the pattern matching regions disposed at the circumference of the regions for correction is extracted, (b). In succession, the grid in the pattern matching region is converted to G1 larger than the input data grid G0. After the pattern matching is executed about all the regions for correction, the classified pattern matching regions are corrected. The pattern matching is executed after the conversion to the large grid G1, by which the pattern matching regions having a difference below G1 on the input data are decided to be the same to each other and the matching efficiency can be enhanced.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a semiconductor manufacturing process and a photomask used therein, and more particularly to a semiconductor manufacturing process and a photomask suitable for forming a fine pattern.

[0002]

2. Description of the Related Art As the degree of integration of LSIs increases and the size of elements formed in LSIs becomes smaller, the fidelity of pattern transfer in a lithography process has begun to become a problem. More specifically, phenomena such as rounding of corners, which should be 90 ° in design, shortening of line ends, and increasing / decreasing of line width occur (optical proximity effect). If the absolute value of the allowable dimensional error decreases as the pattern becomes finer, the allowable dimensional error may exceed the allowable dimensional error due to the optical proximity effect.
Causes of the optical proximity effect include optical factors (interference of transmitted light between adjacent patterns), resist processes (bake temperature / time, development time, etc.), reflection and unevenness of the substrate, influence of etching, and the like. . As a method for preventing the pattern fidelity from deteriorating due to the optical proximity effect, a method in which a correction that allows for the degradation in advance to the mask is mainly used (optical proximity effect correction).

[0003] As a conventional example for performing the optical proximity effect correction automatically and at high speed, there is PH08-339636. In this conventional example, a correction table is referred to as a pattern matching zone in which the target graphic or a region circumscribing the target graphic or the circumscribed rectangle of the target graphic is oversized by the distance that the optical proximity effect reaches. In the correction table, the pattern information of the pattern matching zone corresponds to the corrected figure. If the pattern matching zone of the pattern of interest is included in the correction table, the corrected graphic is acquired. If not, the pattern matching zone is repeatedly subjected to lithography simulation to obtain a corrected shape, and is newly added to the correction table. That is, by performing pattern matching, the number of times of calculation of the corrected shape by lithography simulation is reduced, and the processing is speeded up.

[0004]

In the prior art, for input data having a large grid or data of a memory product having a large number of repetitive patterns, the pattern matching efficiency is high, and the number of times of calculating the corrected shape by lithography simulation is sufficient. It is possible to hold down.

On the other hand, in the case of data obtained by scaling down the original design data and having a small grid or logic data having a small number of repetitions, it is determined that the pattern differs due to a small difference of about several grids, and the pattern matching efficiency becomes low. There is a problem that the processing time becomes enormous.

[0006]

The present invention for solving the above problems employs the following constitution. (1) In a mask drawing data creation method used in lithography, a step of extracting a part of a pattern layout of input data having a design grid (G ₀ ), and extracting a grid of a pattern layout of the extracted region from G ₀ a step of converting a large G _1, characterized in that it comprises a step of pattern matching a pattern layout defined in G _1.

(1-1) The method of creating mask drawing data further includes a step of correcting a pattern that has undergone pattern matching, and a step of reflecting the correction for the matched pattern in the entire input data.

(1-1-1) Regarding pattern correction,
Any one of mask drawing, mask resist development, etching for mask pattern formation, wafer exposure, wafer resist development, and wafer pattern etching
Deform the pattern so as to compensate for the proximity effect generated in one or more steps, or adjust the dose applied to the pattern when drawing the mask.

(1-2) The step of transforming the grid of the pattern matching area includes the step of:
- (the N 2 or greater natural number) the N divided into regions of respectively converted into the grid is greater than G ₁ ~ G _N of G ₀ for pattern layout of each region that.

(2) A method of creating mask drawing data used in lithography, comprising a step of converting pattern data defined by a first data grid into a second grid larger than the first data grid. And

(3) In a mask drawing data generating apparatus used in lithography, a means for extracting a part of a pattern layout of input data having a design grid (G ₀ ) and a grid for a pattern layout of the extracted area are used. means for converting the G ₀ is greater than G _1, reflecting the pattern layout defined by G ₁ and means for pattern matching, and means for correcting the pattern matching pattern, the entire input data correction for matching pattern And means for causing it to be included.

(4) A program for creating drawing data of a mask used in lithography by a computer, a procedure for extracting a part of a pattern layout of input data having a design grid (G ₀ ), and a step of converting the region grid pattern layout of the G ₀ is greater than G ₁ has, a step of pattern matching a pattern layout defined in G _1, a step of correcting the pattern matching pattern matching pattern And a program for executing a procedure for reflecting the correction to the entire input data.

According to (action) the present invention, by performing pattern matching has been translated to a larger grid G ₁ grid G ₀ of the input data, the pattern matching area having a difference of less than G ₁ on the input data will be to each other are determined to be identical, it is possible to increase the matching efficiency than the pattern matching remains G _0.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS (First Embodiment) An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a flowchart for explaining a mask drawing data creation method according to the first, second, and third embodiments. The input data shown in FIG. 2A will be described as a specific example. The input data grid G ₀ is, in this example,
At 1 nm, the coordinate value of the input data shown in FIG.
It is displayed.

First, a point or area to be corrected is extracted (FIG. 1, STEP 0). Here, a rectangle of 0.2 μm square is to be corrected. Subsequently, the following processing is performed for each correction target area.

First, a pattern layout of a pattern matching area provided around the correction target area is extracted (FIG. 1).
(STEP1, FIG. 2 (b)). Here, the size of the pattern matching area is a 0.5 μm area outside the 0.2 μm rectangle. Subsequently grid pattern matching area is converted into _{G 0} is greater than _{G 1} (FIG. 1 STEP
2, FIG. 3 (a)). In the stage of grids _{G 0,} the pattern matching area A, B, although different in C, and the grid _{G 1}
After the conversion, the pattern matching areas of A and C match when mirror-inverted about the y-axis center. Therefore, the pattern matching areas of A, B, and C can be classified into two types, pattern 1 and pattern 2. (Fig. 1 STEP3, Fig. 3
(A)).

After pattern matching has been performed for all correction target areas, the classified pattern matching areas are corrected (STEP 4 in FIG. 1, FIG. 3B). In this embodiment, protrusions (serifs) are formed at the corners of the pattern so as to correct the optical proximity effect when the mask pattern is transferred onto the wafer.
Was added. The shape and amount of correction may be any of the phenomena that cause proximity effects such as mask drawing, mask development, etching for mask pattern formation, wafer exposure, wafer resist development, and wafer pattern etching. It is determined by whether to correct.

In particular, when mask drawing is performed with a charged particle beam, it is necessary to correct the proximity effect caused by backscattered electrons. As a method of correcting the proximity effect, the dose of pattern irradiation can be adjusted without deforming the pattern. May be adjusted. In this case, as a result of correcting the pattern matching area, the figure is not deformed, but information on the dose is given to the correction target area.

The result of reflecting the result of correcting each pattern matching area on the entire input layout (FIG. 1 STE
P5), the layout after correction shown in FIG. 3C is obtained. (Second Embodiment) FIG. 4 is a diagram for explaining a mask drawing data creation method according to the fourth embodiment. FIG. 4A illustrates a pattern matching area of the pattern A. This area includes patterns B, C, and D. The grid is defined at 1 nm. The coordinates in FIG. 4 are expressed in μm units. In the present embodiment, the pattern matching area is divided into a 1.8 μm square area around the pattern A and an area up to 3.2 μm square outside the pattern A. In the former area, the grid is converted to 5 nm, and the latter is converted to 5 nm. Was converted to 10 nm. Since the effect of the proximity between the normal patterns becomes smaller as the distance increases, the influence of the rounding is smaller even if the effect is rounded to a larger grid in a region farther from the pattern of interest.

FIG. 4B shows the result of grid conversion for the pattern matching shown in FIG. Since pattern B originally had a width of only 5 nm, the pattern disappeared as a result of grid conversion.

In the present embodiment, the region is divided into rectangular shapes, but may be divided concentrically around the pattern of interest.

Further, as another method of area division, a grid that defines the correction target pattern disposed in the center of the pattern matching area and G _f, grid G _c (G _f that defines the other pattern < G relationship of _c) may be used. (Third Embodiment) FIG. 5 is a flowchart for explaining a mask drawing data creation method according to the fifth embodiment. After layout design is completed (STEP
0), the layout data are defined by the grid G _0. Processing for converting the G ₀ is greater than the grid _{G 1} (S
Perform TEP1). When setting the G ₁ takes into account the balance of the accuracy deterioration due to rounding reduction and grid data amount by increasing the grid. further,
It is preferable that the data grid of the mask drawing apparatus and the data grid of the mask inspection apparatus are matched. G ₁
For the pattern data 0 defined in
Pattern data processing 1 including calculation (STEP
2), optical proximity correction (STEP 3), pattern data processing 2 (STEP 4) in consideration of a mask process, and formatting into drawing data (STEP 5) are sequentially performed. S
The grid conversion of the TEP1 may be performed anywhere after the layout design until before the mask drawing data is generated. However, it is preferable to perform the grid conversion upstream as much as possible because the amount of processing data in the subsequent processing can be reduced. Table 1 shows the relationship between grid size and data amount / processing time.
By increasing the grid, the amount of data can be significantly reduced, and the processing time can be reduced. (Fourth Embodiment) FIG. 6 is a block diagram of a mask drawing data creating apparatus according to the sixth embodiment. The present apparatus is realized by a computer which reads a program recorded on a recording medium such as a magnetic disk and the operation of which is controlled by the program.

This apparatus is roughly composed of a control unit 20, a display unit 30, an input unit 40, a pattern data storage unit 50, and a pattern matching table 60.

The control section 20 first uses the pattern layout extracting means 21 to extract a partial pattern layout of the input data. Here, the input data grid is G ₀
And Subsequently, using a grid converter 22, converts the pattern layout of the extracted region G ₀ is greater than G _1. Further, using the pattern matching means 23,
A defined pattern layout in G ₁ classified with reference to the pattern matching table 60. The matching pattern correction unit 24 corrects each of the pattern layouts included in the pattern matching table. The correction shape and correction amount are defined as any of the phenomena that cause proximity effects such as mask drawing, mask resist development, etching for mask pattern formation, wafer exposure, wafer resist development, and wafer pattern etching. It is determined by whether to correct.

Finally, the correction result of the pattern matching area is reflected on the entire layout using the means 25 for reflecting the correction on the entire layout. The corrected layout is stored in the pattern data storage unit 50.

With such a configuration, the mask drawing data can be effectively created in the first to third embodiments described above.

The method described in the above embodiment may be a program that can be executed by a computer, for example, a magnetic disk (floppy (registered trademark) disk, hard disk, etc.), an optical disk (CD
-ROM, DVD, etc.), writing to a recording medium such as a semiconductor memory and applying to various devices, or transmitting to a communication medium and applying to various devices. A computer that realizes the present apparatus reads the program recorded on the recording medium, and executes the above-described processing by controlling the operation of the program.

[0028]

According to the present invention, when the optical proximity effect correction, larger grid G ₀ of the input data grid G
By performing pattern matching after converting to _1, will be pattern matching between the regions with differences of less than G ₁ on the input data is determined to be identical,
It is possible to improve the matching efficiency than the pattern matching remains G _0. When the efficiency of the pattern matching is improved, the number of times of processing for calculating a correction shape by lithography simulation, which takes time, can be reduced, and the speed of the optical proximity effect correction processing can be improved.

[Brief description of the drawings]

FIG. 1 is a flowchart for explaining a mask drawing data creation method according to a first embodiment.

FIG. 2 is a diagram for explaining a first embodiment.

FIG. 3 is a diagram for explaining a second embodiment.

FIG. 4 is a diagram for explaining a second embodiment.

FIG. 5 is a flowchart for explaining a third embodiment.

FIG. 6 is a block diagram showing a configuration of a fourth embodiment.

Continuation of the front page (72) Inventor Uga 1-ga, Komukai Toshiba-cho, Saiwai-ku, Kawasaki-shi, Kanagawa Prefecture F-term in the Toshiba R & D Center (reference) 2H095 BA05 BB01 BB32 BB36 5B046 AA08 BA04 FA04 JA02

Claims (7)

[Claims] In a method for creating mask drawing data used in lithography, a step of extracting a part of a pattern layout of input data having a design grid (G ₀ ) and a step of extracting a pattern layout grid of the extracted region into G a step of converting greater than ₀ G _1, the mask drawing data generation method characterized by comprising the step of pattern matching a defined pattern layout in the G _1. 2. The method according to claim 1, further comprising a step of correcting the pattern-matched pattern and a step of reflecting the correction on the matched pattern in the entire input data. How to create mask drawing data. 3. The pattern correction according to claim 2, wherein at least one of mask drawing, mask resist development, etching for mask pattern formation, wafer exposure, wafer resist development, and wafer pattern etching. Forming a pattern so as to compensate for the proximity effect that occurs in the step (b), or adjusting an irradiation amount given to the pattern during mask drawing. 4. The method according to claim 1, wherein the step of converting the grid of the pattern matching area includes dividing the pattern matching area into first to N-th (N is a natural number of 2 or more) areas, and About layout G
A mask drawing data creation method, wherein the conversion is performed to G _{1 to} G _N larger than a grid of ₀ , respectively. 5. A method for creating mask drawing data used in lithography, comprising a step of converting pattern data defined by a first data grid into a second grid larger than the first data grid. To create mask drawing data. 6. An apparatus for creating a mask drawing data used in lithography, comprising: means for extracting a partial pattern layout of input data having a design grid (G ₀ ); means for converting greater than ₀ G _1, reflect the defined pattern layout in the G ₁ and means for pattern matching, and means for correcting the pattern matching pattern, the entire input data correction for matching pattern A mask drawing data creating apparatus. 7. A program for creating, by a computer, writing data of a mask used in lithography, a procedure for extracting a part of a pattern layout of input data having a design grid (G ₀ ), and a step of converting a grid pattern layout of region G ₀ is greater than G _1, a procedure of the pattern matching a defined pattern layout in this G _1, the procedure for correcting the pattern matching pattern matching pattern Computer-readable recording medium storing a program for executing a procedure for causing a correction to be applied to the entire input data.