KR100554916B1 - Micro pattern configuring method in designing mask - Google Patents

Abstract

The present invention relates to a method for forming a fine pattern in mask design.

The present invention comprises the steps of fine transitioning a portion of the main pattern perpendicular to the longitudinal direction of the pattern; And changing the design magnification and the design unit to form a mask, and then forming a fine auxiliary pattern by the fine transitioned main pattern.

Therefore, when the semiconductor mask pattern having a repetitive cell is formed, the present invention finely transitions a part of the main pattern perpendicularly to the longitudinal direction of the pattern, and then changes the design magnification and design unit to form a mask, and then fine transitions. By forming the fine auxiliary pattern by the formed main pattern, the line width of the pattern can be maintained uniformly, and the fine auxiliary pattern and the main pattern can be OPC processed in the same layer, so that mask manufacturing is accurate and easy.

Description

MICRO PATTERN CONFIGURING METHOD IN DESIGNING MASK}             

1 is a process cross-sectional view showing a semiconductor mask pattern having a conventional repetitive cell.

2 is a cross-sectional view illustrating an example of forming a fine pattern on a main pattern when forming a semiconductor mask pattern having a repeated cell in the method of forming a fine pattern in designing a mask of the present invention;

3 is a cross-sectional view illustrating an example in which the design of FIG. 2 is reduced by 72% in the method of forming a fine pattern when designing a mask of the present invention;

Figure 4 is a process cross-sectional view showing an example in the case of changing the unit of the minimum division to 5nm in the method of forming a fine pattern when designing the mask of the present invention.

Figure 5 is a process cross-sectional view showing an example of converting a fine pattern formation method applied to the actual main database in the mask design of the present invention.

Figure 6 is a process cross-sectional view showing an example in which a fine auxiliary pattern is represented by a repeating cell in the method of forming a fine pattern in the mask design of the present invention.

FIG. 7 is a cross-sectional view illustrating an example of applying an optical proximity compensation technique (OPC) to the repeating cell of FIG. 6 in the method of forming a fine pattern when designing a mask of the present invention. FIG.

*** Description of the symbols for the main parts of the drawings ***

10,11,20,21: Cell instances 10A, 11A, 20A, 21A: Main pattern

30: residual pattern

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a mask, and in particular, when forming a semiconductor mask pattern having repetitive cells, a small portion of the main pattern is vertically shifted perpendicularly to the longitudinal direction of the pattern, and then the design magnification and design unit are changed to repeat the process. The present invention relates to a method of forming a fine pattern in a mask design for forming a fine auxiliary pattern around a cell.

The mask pattern forming technique has a close influence on the accuracy of the pattern formed on the semiconductor substrate. In particular, if the optical proximity effect of the mask pattern is not properly considered, pattern linewidth distortion occurs, unlike the original lithography intention of exposure, resulting in a shortening of line width linearity, which adversely affects semiconductor device characteristics. .

In addition, the semiconductor photolithography technology allows precise control of the mask design, so that the amount of light emitted by the mask can be properly adjusted, and for this, an optical proximity compensation technology and a phase shifting mask technology are used. Various methods are used to minimize the distortion of light due to the pattern shape drawn on the mask.

In particular, recent developments of chemically amplified resists with excellent photosensitivity to light at far ultraviolet wavelengths (248 nm or 194 nm) have resulted in practical technologies that can further increase the resolution. Auxiliary pattern for controlling the shape, that is, a kind of dummy pattern (dummy pattern) forming technology also contributes to the improvement of the resolution.

1 is a cross-sectional view illustrating a semiconductor mask pattern having a conventional repetitive cell. In general, the line width of the pattern 1 has a line width bias between the isolation pattern and the dense pattern according to the separation distance of the peripheral pattern 1. In the case of the isolated pattern, a manufacturing technique of inserting the fine auxiliary pattern 3 as a dense pattern is used.

Insertion of the fine auxiliary pattern 3 is compensated near the main pattern, which is mainly isolated by measuring the distance between adjacent patterns 1, and the method of compensating by measuring the distance is called DRC (Design Rule Check). do.

The fine auxiliary pattern 3 is a fine pattern having a line width of less than or equal to the limit resolution so that the fine auxiliary pattern 3 is present in the mask but is not actually formed on the semiconductor substrate after exposure.

Here, the definition of pattern resolution is based on the Rayleigh equation,

R (Resolution) = k * λ / N.A.

Where k is a constant, λ is the illumination wavelength, and N.A. is the illumination lens aperture.

For example, if k is 0.5, λ is 0.248, and NA is 0.65, the resolution R = 0.19um is obtained. Therefore, when a micro pattern having a line width smaller than this value is independently applied to the mask, only the mask is physically light-transmitted. The resist can then define a pattern that does not appear in the image.

In addition, when the spacing between the main patterns (1) is close (2), the fine auxiliary pattern (3) causes the bridge between the patterns and should not be inserted, but when the spacing between the main patterns (1) is apart (4) This is possible.

In particular, in the latter case, the cell pattern 1 is arranged in a bent structure, and line width uniformity becomes very important when the cell pattern is a gate.

Therefore, it is not easy to arrange the fine auxiliary pattern 3 in the loading place, and the fine auxiliary pattern 3 needs to be modified and arranged by hand, thereby increasing the time and cost.

Accordingly, the present invention has been proposed to solve the above-mentioned conventional problems. When forming a semiconductor mask pattern having a repetitive cell, a part of the main pattern is finely shifted perpendicularly to the longitudinal direction of the pattern, and then the design magnification and It is an object of the present invention to provide a method of changing a design unit to form a fine auxiliary pattern around a repetitive cell.

The present invention for achieving the above object comprises the steps of finely transitioning a part of the main pattern perpendicular to the longitudinal direction of the pattern; And forming a mask by changing a design magnification and a design unit, and then forming a fine auxiliary pattern by the fine transitioned main pattern.

Hereinafter, an embodiment according to the present invention will be described in detail with reference to the accompanying drawings.

FIG. 2 is a cross-sectional view illustrating an example of forming a fine pattern on a main pattern when forming a semiconductor mask pattern having repeating cells. The main patterns 10A, 11A, 20A, and 21A are cell instances of individual units. (10, 11, 20, 21) is included in the structure, it is possible to construct a large capacity by repeatedly copying the same individual cells.

At this time, the fine transition (5) of the cell instances (10, 11, 20, 21) selectively about 1 nm (0.001um) in the longitudinal direction and the vertical direction of the repeating pattern by the same size selectively Let's do it.

Then, fine transitions 5 occur in the vertical direction by 1 nm with respect to the main patterns 20A and 21A in the transitioned cell instances 20 and 21.

Here, the dotted line 100 represents the position before the fine transition 5 of the cell instances 20 and 21.

Next, the design magnification and design scale of the main patterns 10A, 11A, 20A, and 21A, which are finely transitioned 5, are changed as shown in FIG. 2, and FIG. 3 is a process cross-sectional view of 72% of the design of FIG. In FIG. 2, if the line widths of the individual main patterns 10A, 11A, 20A, and 21A are 0.25 um, when the line width is reduced by 72%, the line width is 0.18 nm.

At this time, the cell instances 20 and 21 are transitioned 5 'by 1 nm, so that 0.249 um is changed to 0.179 nm.

4 illustrates a case in which the grid of the minimum division is changed to 5 nm in the process of shrinking and converting only 72% from a commercial design tool, and the unit cell instance 20, which has been transitioned 5 'in FIG. 21 is rearranged to match the baseline 100 'of the untransitioned cell instances 10 and 11.

At this time, 0.001 nm remains in a pattern as much as the portion which has been transitioned 5 'in the process of rearrangement in accordance with the reference line 100'.

Here, the reason for converting the design scale in units of 5 nm is to reduce the cost of the mask by optimizing the amount of data, and based on the unit of 5 nm, the unit of 1 nm is an off unit, so 5 nm is used during the unit conversion process. It is aligned with one hypotenuse of the unit of.

Then, the patterns 11A 'and 20A' in which one hypotenuse of the line width is reduced by the residual pattern 30 are generated.

FIG. 5 is a cross-sectional view of a process obtained by applying the method according to the present invention to an actual main database, and when unit cells are drawn, overlapping unit cells 40A and 40B connected to each other with the same line width during the cell conversion process (40AB) I draw it.

At this time, the unit cell 40B has a 1 nm difference 50 in the vertical direction, and the width of the main pattern 70 immediately above the remaining pattern 60 is reduced by 1 nm.

As a result, in order to accurately compensate for the bent portion of the unit cell 40A, the residual pattern 60 remains before the pattern overlapping portion 40AB to form a fine auxiliary pattern, and the fine auxiliary pattern is fine on one side of the unit main pattern. If the auxiliary pattern is arranged in parallel has a structure that is not arranged on the other side.

In addition, the formed fine auxiliary pattern is represented by a repeating cell as shown in FIG. 6, and FIG. 7 illustrates an example of applying optical proximity compensation technology to the repeating cell of FIG. 6.

Here, the optical proximity compensation technique is also applied to the fine auxiliary pattern, so that the line width of the residual pattern 60, that is, the fine auxiliary pattern can be adjusted to a desired line width.

Therefore, according to the present invention, it is possible to apply a fine press pattern without a separate fine auxiliary pattern generation program, to be easily applied to a symmetrical pattern, and to keep the line width of the pattern uniform, thereby uniformizing NMOS and PMOS device characteristics. Can be secured.

As described above, when forming a semiconductor mask pattern having a repetitive cell, the present invention finely transitions a part of the main pattern perpendicularly to the longitudinal direction of the pattern, and then changes the design magnification and design unit to form a mask. After the fine auxiliary pattern is formed by the fine transitioned main pattern, the line width of the pattern can be maintained uniformly, and the micro auxiliary pattern and the main pattern can be OPC-treated in the same layer, so that mask manufacturing is accurate and easy. .

Claims (3)

Finely shifting a portion of the main pattern perpendicularly to the longitudinal direction of the pattern; And forming a mask by changing a design magnification and a design unit, and then forming a fine auxiliary pattern by the fine transitioned main pattern. The method of claim 1, wherein the fine auxiliary pattern is formed to be the same as the length of the unit main pattern so as to be parallel to the main pattern. The method of claim 1, wherein the fine auxiliary pattern is not disposed on the other side when the fine auxiliary pattern is arranged parallel to one side of the unit main pattern.

Images