JP3461305B2 - Mask drawing data creation method, creation device, and recording medium - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention 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 integration density of LSIs has increased and the size of elements to be formed in LSIs has become smaller, the fidelity of pattern transfer in a lithography process has begun to become a problem. Specifically, a phenomenon such as a corner that is supposed to be 90 ° in design is rounded, a line end is shortened, and a line width is widened / thinned (optical proximity effect). If the absolute value of the allowable dimensional error decreases with the miniaturization of the pattern, the optical dimensional proximity effect may exceed the allowable dimensional error.
The causes of the optical proximity effect include optical factors (interference of transmitted light between adjacent patterns), resist process (baking temperature / time, development time, etc.), substrate reflection and unevenness, and effects of etching. . As a method of preventing the problem that the pattern fidelity is deteriorated by the optical proximity effect, a method of applying a correction to the mask in advance considering deterioration is the mainstream (optical proximity effect correction).

PH08-339636 is a conventional example for automatically and rapidly correcting the optical proximity effect. In this conventional example, the correction table is referred to by using an area in which the figure of interest or a circumscribed rectangle of the figure of interest is oversized by a distance covered by the optical proximity effect as a pattern matching zone. In the correction table, the pattern information of the pattern matching zone corresponds to the corrected figure. If the pattern matching zone of the figure of interest is on the correction table, the corrected figure is acquired, and if it is not on the pattern matching zone, the pattern matching zone is repeatedly subjected to lithography simulation to obtain the corrected shape, and the pattern is newly added to the correction table. That is, by performing the pattern matching, the number of times of the correction shape calculation processing by the lithography simulation is reduced, and the processing speed is increased.

[0004]

In the prior art, the pattern matching efficiency is good for input data with a large grid or data of a memory product with many repetitive patterns, and the number of times of correction shape calculation processing by lithography simulation is sufficient. It is possible to hold down.

On the other hand, in the case of data obtained by reducing and scaling the original design data and having a small grid, or logic data having a small number of repetitions, it is determined that the patterns are different due to a small difference of 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 adopts the following configuration. (1) In the method of creating drawing data of a mask used in lithography, a step of extracting a pattern layout of a part of input data having a design grid (G ₀ ), and a grid of the pattern layout of the extracted region from G ₀ It is characterized by including a step of converting into a large G ₁ and a step of pattern matching the pattern layout defined by G ₁ .

(1-1) The mask drawing data creating method further includes a step of correcting the pattern-matched pattern and a step of reflecting the correction of the matched pattern on the entire input data.

Regarding (1-1-1) pattern correction,
Any one of mask drawing, mask resist development, etching for mask pattern formation, wafer exposure, wafer resist development, and wafer pattern etching
To modify the pattern so as to compensate for the proximity effect that occurs in one or more steps, or to adjust the irradiation dose given to the pattern during mask writing.

(1-2) In the step of converting the grid of the pattern matching area,
~ Dividing into an N-th (N is a natural number of 2 or more) region and converting the pattern layout of each region into G ₁ to G _N larger than the grid of G ₀ .

[0010]

(2) In a mask drawing data creation device used in lithography, a unit for extracting a pattern layout of a part of input data having a design grid (G ₀ ) and a pattern layout grid for the extracted region are provided. A means for converting to G ₁ larger than G _0, a means for pattern matching the pattern layout defined by G ₁ , a means for correcting the pattern-matched pattern, and a correction for the matched pattern reflected on the entire input data And a means for causing it.

(3) A program for creating drawing data of a mask used in lithography by a computer, and a procedure for extracting a pattern layout of a part of input data having a design grid (G ₀ ), and the extracted procedure. 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 for the whole input data.

(Operation) According to the present invention, the pattern matching area having a difference of less than G ₁ on the input data is obtained by converting the grid G _{0 of the} input data into the larger grid G ₁ and then performing the pattern matching. Since it is determined that the two are the same, it is possible to improve the matching efficiency as compared with the case of performing the pattern matching with G ₀ as it is.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments (First Embodiment) Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a flow chart for explaining a mask drawing data creating 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, the point or area to be corrected is extracted (STEP 0 in FIG. 1). Here, a rectangle of 0.2 μm □ is a correction target. Then, the following processing is performed for each correction target area.

First, the pattern layout of the pattern matching area provided around the correction target area is extracted (see FIG. 1).
STEP 1, FIG. 2B). Here, the size of the pattern matching area is 0.5 μm outside the rectangle of 0.2 μm. Then, the grid of the pattern matching area is converted into G ₁ which is larger than G ₀ (FIG. 1 STEP).
2, FIG. 3 (a). At the stage of the grid G ₀ , the pattern matching areas A, B, and C are different, but the grid G ₁
After the conversion, the pattern matching areas of A and C match if mirror-inverted about the y-axis center, so 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 performing pattern matching on all the correction target areas, the classified pattern matching areas are corrected (FIG. 1 STEP 4, 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 of the correction and the amount of correction are determined by the phenomenon that causes proximity effects such as mask drawing, mask resist development, etching for mask pattern formation, wafer exposure, wafer resist development, and wafer pattern etching. Determined by whether to correct.

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

The result of the correction of each pattern matching area reflected on the entire input layout (see FIG. 1 STE).
P5), the corrected layout shown in FIG. 3C is obtained. (Second Example) FIG. 4 is a diagram for explaining a mask drawing data creating method according to the fourth embodiment. FIG. 4A shows the pattern matching area of the pattern A, and the areas B, C, and D are included in this area. The grid is defined at 1 nm. The coordinates in FIG. 4 are displayed in μm units. In this embodiment, the pattern matching area is divided into an area of 1.8 μm □ centered on the pattern A and an area of 3.2 μm □ outside the pattern matching area. In the former area, the grid is converted to 5 nm and the latter area is converted into the latter. In the region of, the wavelength was converted to 10 nm. Normally, the proximity effect between patterns decreases as the distance increases, so even if the area is farther from the pattern of interest, the effect of the rounding is small even if the area is rounded to a larger grid.

FIG. 4 (b) shows the result of grid conversion for the pattern matching of FIG. 4 (a). 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 it may be divided into concentric circles centering on the pattern of interest.

As another method of area division, a grid defining a pattern to be corrected arranged in the center of the pattern matching area is defined as G _f, and a grid defining other patterns is defined as G _c (G _f < _{(There is} a relationship of G _c ). FIG. 5 is a flow chart for explaining the process in the mask drawing data creation according to the above embodiment. After the layout design is completed (STE
P0), the layout data is defined by the grid G ₀ . A process (STEP 1) of converting to a grid G ₁ larger than G ₀ is performed. When setting G ₁ , the balance between the effect of reducing the amount of data by enlarging the grid and the deterioration of accuracy due to grid rounding is considered. Furthermore, it is preferable that the data grid of the mask drawing apparatus and the data grid of the mask inspection apparatus are matched.
For the pattern data 0 defined by G ₁ , Boolean
Pattern data processing 1 including an operation (STEP
2), optical proximity effect correction (STEP 3), pattern data processing 2 (STEP 4) in consideration of the mask process, and format (STEP 5) for drawing data are sequentially performed. S
The grid conversion of TEP1 may be performed anywhere after the layout design and before the mask drawing data is generated, but it is preferable to perform the grid conversion as upstream as possible because the amount of processing data in the subsequent processing can be reduced. Table 1 shows the relationship between the grid size and the data amount / processing time.
By enlarging the grid, the amount of data can be significantly reduced and the processing time can be shortened. (Third Embodiment) FIG. 6 is a block diagram of a mask drawing data creation apparatus according to the fifth embodiment. The present apparatus is realized by a computer that reads a program recorded on a recording medium such as a magnetic disk and the operation of which is controlled by the program.

The apparatus is roughly divided into a control section 20, a display section 30, an input section 40, a pattern data storage section 50, and a pattern matching table 60.

In the control section 20, first, the pattern layout extracting means 21 is used to extract a part of the pattern layout of the input data. Here, the input data grid is G ₀
And Then, the grid conversion means 22 is used to convert the pattern layout of the extracted region into G ₁ which is larger than G ₀ . Furthermore, using the pattern matching means 23,
The pattern layout defined by G ₁ is classified with reference to the pattern matching table 60. The matching pattern correction means 24 respectively corrects the pattern layouts included in the pattern matching table. The shape of the correction and the amount of correction are determined by the phenomenon that causes proximity effects such as mask drawing, mask resist development, etching for mask pattern formation, wafer exposure, wafer resist development, and wafer pattern etching. Determined by whether to correct.

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

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

The methods described in the above embodiments are, for example, magnetic disks (floppy (registered trademark) disks, hard disks, etc.), optical disks (CDs) as programs that can be executed by a computer.
-ROM, DVD, etc.), it is also possible to write on a recording medium such as a semiconductor memory and apply it to various devices, or to transmit it via a communication medium and apply it to various devices. A computer that realizes the present device reads a program recorded in a recording medium, and the operation is controlled by the program to execute the above-described processing.

[0028]

According to the present invention, when correcting the optical proximity effect, the grid G ₀ of the input data is set to a larger grid G _0.
By performing pattern matching after converting to ₁ , it is determined that the pattern matching areas having a difference of less than G ₁ on the input data are the same.
It is possible to improve the matching efficiency as compared with performing the pattern matching with G ₀ as it is. When the efficiency of pattern matching is improved, it is possible to reduce the number of times of the correction shape calculation processing by the time-consuming lithography simulation, and it is possible to improve the speed of the optical proximity effect correction processing.

[Brief description of 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 the 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 process in creating mask drawing data .

FIG. 6 is a block diagram showing a configuration of a third exemplary embodiment.

─────────────────────────────────────────────────── ─── Continuation of the front page (56) Reference JP-A-10-209000 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G03F 1/08

Claims (6)

(57) [Claims] 1. A method of creating a drawing data of a mask used in lithography, a step of extracting a pattern layout of a part of input data having a design grid (G ₀ ), and a grid of the pattern layout of the extracted area being G A mask drawing data creating method comprising: a step of converting into G ₁ larger than ₀ ; and a step of pattern matching the pattern layout defined by this G ₁ . 2. The mask drawing data creating method according to claim 1, further comprising a step of correcting the pattern-matched pattern, and a step of reflecting the correction of the matched pattern on the entire input data. Mask drawing data creation method. 3. The pattern correction according to claim 2, wherein one or more of mask drawing, mask resist development, etching for mask pattern formation, wafer exposure, wafer resist development, and wafer pattern etching are performed. The mask drawing data creating method, characterized in that the pattern is deformed so as to compensate for the proximity effect generated in the step of (1) or the irradiation amount given to the pattern is adjusted at the time of mask drawing. 4. The step of converting a grid of a pattern matching area according to claim 1, wherein the pattern matching area is divided into first to Nth areas (N is a natural number of 2 or more), and the pattern of each area is divided. About layout G
Mask drawing data creation method and converting each ₀ grid greater than G ₁ ~G _N. 5. Drawing of a mask used in lithography
Have a design grid (G ₀ ) in the data creation device
A means to extract part of the pattern layout of input data
And the pattern layout grid of the extracted area
Means to convert to G ₁ which is larger than G ₀ and defined by this G ₁
To pattern-match the defined pattern layout
Steps and hands to correct the pattern-matched pattern
Step and input pattern correction for the matched pattern.
And a means for reflecting the data on the entire computer.
Disk drawing data creation device. 6. Drawing of a mask used in lithography
A program for creating data by computer
Of the input data with the design grid (G ₀ )
The steps to extract some pattern layouts and the extracted
And the region grid pattern layout of greater than G ₀
A step of converting the stomach G _1, defined putter in the G ₁
Pattern matching procedure and pattern
Matching procedure to correct the matched pattern
Correction for the filled pattern
Store the program to execute the procedure and
Computer readable recording medium.