JP3301400B2 - How to create data for pattern drawing - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for forming pattern drawing data for forming a pattern on a light exposure mask by an electron beam drawing apparatus.

[0002]

2. Description of the Related Art At present, in a light exposure apparatus used for manufacturing a semiconductor device such as a DRAM, a light exposure mask (also known as a reticle) formed by enlarging a circuit pattern of an actual semiconductor device by 5 to 10 times. ), And reduced projection exposure for forming a circuit pattern on a wafer coated with a resist has become mainstream. However, as the circuit pattern of the semiconductor device has been miniaturized and the wavelength of the exposure light of the light exposure device has approached the width of the circuit pattern of the semiconductor device, the corners and sides of the pattern formed on the light exposure mask have been reduced. A problem due to the proximity effect of light, in which light diffraction and interference occur in the peripheral portion, and the resolution and the depth of focus are insufficient and the optical image is distorted, has become significant. In a normal light exposure mask, the proximity effect causes deformation of the resist pattern after exposure, such as shrinkage of the long side of the circuit pattern and swelling of the corners.
It has become difficult to form a circuit pattern of a semiconductor device having a desired size on a wafer. Therefore, in order to eliminate the deformation of the circuit pattern after light exposure, it is necessary to perform proximity effect correction in which the pattern of the light exposure mask is corrected in advance in consideration of the distortion amount of the optical image.

In general, when designing or correcting the shape of a pattern to be formed on a light exposure mask, a line regularly arranged in a grid pattern with a certain fixed width is used on this line. When designing the shape of the pattern, the place where the circuit pattern of the semiconductor device is arranged is not arbitrary, and the circuit pattern is arranged at the intersection of the lines regularly arranged in a grid pattern with the above-mentioned fixed width. Hereinafter, the state of the lines regularly arranged in the form of a grid with the constant interval width is referred to as a grid, the line is referred to as a grid line, and the interval between the grid lines is referred to as a grid interval.

The above-described grid reduces the scanning pitch of an electron beam lithography system (hereinafter referred to as a lithography grid) used for drawing a pattern on a light exposure mask by reducing the projection pitch of a light exposure system used in a lithography process of a semiconductor device. The value is reduced by the rate. For example, the projection reduction ratio of the light exposure device is 1/5
In the case of (1), the grid used when designing the pattern to be arranged on the light exposure mask is １ ／ of the drawing grid for drawing the pattern on the light exposure mask.

When finely adjusting the pattern formed on the light exposure mask by the optical proximity effect described above, for example, in order to finely adjust the width of the pattern without changing the center position of the pattern, two grids are required. Make fine adjustments by making the unit 1 unit. Specifically, after designing a pattern having a minimum width of 0.2 μm with a grid of 0.01 μm, in order to finely adjust the width of the pattern, the fine adjustment interval is set to 0.01 μm.
m, which is twice as large as 0.02 μm. Accordingly, in order to finely adjust the pattern width so as to increase the width, the pattern width after the fine adjustment is set to 0.22 μm, 0.24 μm, 0.26 μm.
m. . . And On the other hand, for fine adjustment in the direction of narrowing the pattern width, the pattern width after the fine adjustment is 0.18 μm,
0.16 μm, 0.14 μm. . . And At this time,
The interval for fine adjustment of the pattern is 1 with a pattern width of 0.2 μm.
0%.

[0006]

As described above, when correcting the pattern of the light exposure mask, the pattern width of 10
It must be adjusted in dimensional intervals of%. If the dimension interval for correcting the width of the pattern is large, it is impossible to adjust a fine dimension smaller than the dimension interval, and the dimensional accuracy of the pattern of the light exposure mask is reduced.

Further, since a grid used when drawing a pattern on a light exposure mask by an electron beam drawing apparatus is limited, it is difficult to draw a pattern that does not correspond to a drawing grid to a size. In order to form a pattern according to dimensions, it is necessary to set the drawing grid of the electron beam lithography apparatus to about the grid used when correcting the pattern. The problem that the quality decreases more and more occurs.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems of the prior art, and it is an object of the present invention to form a fine pattern on a light exposure mask with high accuracy and without a decrease in throughput. It is an object of the present invention to provide a method for creating pattern drawing data that can be performed.

[0009]

In order to achieve the above object, a method for creating pattern drawing data according to the present invention is directed to a light exposure apparatus.
Electronic line drawing a desired pattern on the light exposure mask used in location
A method for creating pattern drawing data for forming a circuit pattern of a semiconductor device using a first grid having a predetermined grid interval to form a circuit pattern of the semiconductor device as the pattern. And converting the first grid into a second grid obtained by enlarging the reciprocal of the projection reduction ratio of the light exposure device as an enlargement factor, and converting the first pattern into a projection reduction ratio of the light exposure device. Is converted to a second pattern that is enlarged by using the reciprocal of as an enlargement factor, the second grid is enlarged twice to be converted to a third grid, and a second pattern located in the middle of the third grid is transformed. Is extended and moved on the grid line of the third grid to form a third pattern, and within one grid interval of the third grid from the side of the third pattern. In the in the size of the resist used to draw the light exposure mask not resolved
One grid interval to several grid intervals of the third grid
A method of forming a fourth pattern by inserting a fine space having a minute width, the fine space, the light exposure
The resist used when drawing on the optical mask is a negative type
In the case of dying, the electric current on the side of the fourth pattern
The shrinkage dimension of the resist pattern due to the
With a width equal to half the grid spacing of grid 3
The fine space is drawn on the light exposure mask
If the resist used during the process is a positive resist
When the electron dose decreases on the side of the fourth pattern,
And the third dimension of the third grid.
The width is equal to half the grid interval.

[0010]

[0011]

[0012]

[0013] How to create other patterns drawing data of the present invention, a desired pattern on the light exposure mask used in an exposure apparatus for a pattern drawing data creation method for forming the electron beam lithography system, In order to form a circuit pattern of a semiconductor device as the pattern, a first pattern having a predetermined shape is designed using a first grid having a predetermined grid interval, and the first grid is used for the light exposure apparatus . Converting the reciprocal of the projection reduction ratio into a second grid enlarged as an enlargement factor, converting the first pattern into a second pattern enlarged by using the reciprocal of the projection reduction ratio of the light exposure apparatus as an enlargement factor, The second grid is enlarged twice to convert it to a third grid, and the side of the second pattern located in the middle of the third grid is reduced to produce the third grid. A third pattern is formed by moving the third pattern on the grid line, and the resist used when writing on the light exposure mask from the side of the third pattern to one grid interval outside the third grid. A size not to be resolved, from one grid interval of the third grid to
A method of forming a fourth pattern by inserting a fine line having a width of several grid spacing fraction, the fine line
Is a resist used for drawing on the light exposure mask.
When the resist is a negative resist, the fourth pattern
Of resist pattern with increasing electron dose at the edge
The dimensions are equal to half the grid spacing of the third grid
And the fine lines correspond to the light exposure mask.
The resist used when drawing on the mask is a positive resist
, The electron dose on the side of the fourth pattern
The contraction dimension of the resist pattern due to the increase and the third group
The width is equal to half the grid interval of the lid.

[0014]

[0015]

[0016]

In the above-described drawing data creating method,
Data for pattern drawing with a fine space of a size that is not resolved when drawing with an electron beam drawing device inside the pattern of the light exposure mask, or with an electron beam drawing device outside the pattern of the light exposure mask Create pattern drawing data in which fine lines of a size that are not resolved when drawing are arranged. By using this pattern drawing data, a pattern can be drawn in half a grid unit of the drawing grid of the electron beam drawing apparatus.

[0018]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, embodiments of the present invention will be described in detail with reference to the drawings.

First Embodiment First, a description will be given of a method of creating pattern data of a light exposure mask when a resist used when drawing a pattern on the light exposure mask by an electron beam drawing apparatus is a negative type. I do.

First, as a first process, as shown in FIG. 1A, a circuit pattern of a semiconductor device is converted into a first pattern AP1 having a predetermined shape using a first grid G1 having a predetermined grid interval. To design.

Next, as a second process, the first pattern AP1 and the first grid G1 in FIG. 1A are defined by using the reciprocal of the projection reduction ratio of the light exposure apparatus using the light exposure mask as the enlargement magnification value. Expanding. Then, the first pattern AP1
Is enlarged to a second pattern AP2 as shown in FIG. 1 (b), and the first grid G1 is converted to a second grid G2 (in the drawing, the second grid G in FIG. 1 (b) is used).
2 and the first grid G1 in FIG.

Next, as a third process, the second grid G2 enlarged in the second process is further enlarged twice as shown in FIG. 1C and converted into a third grid G3. At this time, the size of the second pattern AP2 is kept as it is without being enlarged. Since the second grid G2 is doubled, the upper and lower sides of the second pattern AP2 are located in the middle of the grid interval of the third grid G3.

Next, as a fourth process, as shown in FIG. 1 (d), the upper and lower sides of the second pattern AP2 located in the middle of the grid interval of the third grid G3 are moved to the third grid G3.
Of the second pattern AP2 on the grid line of the grid G3 of FIG.
Are moved in a direction to increase the size of the pattern, and this is set as a third pattern AP3.

Next, as a fifth process, as shown in FIG. 1 (e), the first fine space S1 is located below the upper side of the third pattern AP3 by one grid interval of the third grid G3.
Is inserted, and the third pattern AP3
A second fine space S2 is inserted one grid interval above the grid G3 of FIG. At this time, the first fine space S1 and the second fine space S
The size of 2 is a size that is not resolved when a pattern is drawn on a light exposure mask using an electron beam drawing apparatus, and has a width h.
Is from one grid interval to several grid intervals of the third grid G3.

When an electron beam lithography system is used to draw a pattern on the light exposure mask using the pattern drawing data having the above-mentioned fourth pattern AP4, the electron dose on the upper side and the lower side of the fourth pattern AP4 becomes the first fine space. It is reduced by inserting the S1 and the second fine space S2.

When the resist applied at the time of drawing the light exposure mask is a negative resist, the long side direction of the fourth pattern AP4 shrinks as the electron dose decreases. At this time,
Shrinkage dimension of fourth pattern AP4 and third grid G3
So that half of the grid spacing of
When the width h of the first fine space S1 and the second fine space S2 to be inserted inside the pattern AP4 is set,
The length of the fourth pattern AP4 in the long side direction is the length before moving the side on the grid line of the third grid G3, that is, the reciprocal of the projection reduction ratio of the light exposure apparatus shown in FIG. It becomes the enlarged second pattern AP2.

Therefore, the second pattern AP2 formed by the second grid G2 which is half the grid interval of the third grid G3 which is the drawing grid of the electron beam drawing apparatus.
Can be drawn using the third grid G3, which is a drawing grid of the light exposure mask.

Next, a description will be given of a case where a positive type register is used when drawing a light exposure mask. Note that the first to fifth processes in the case where the above-mentioned negative resist is used are the same processes, and thus are omitted here.

When the resist applied at the time of drawing the light exposure mask is a positive resist, the resist pattern of the fourth pattern AP4 extends in the long side direction with the decrease in the electron dose. The first minute space S1 and the second minute space S2 inserted inside the fourth pattern AP4 such that the extension dimension of the fourth pattern AP4 and the half of the grid interval of the third grid G3 have the same dimension. Is set, the length in the long side direction of the fourth pattern AP4 becomes the third
1B, ie, the length before moving the side on the grid line of the drawing grid G3, that is, the second pattern AP2 enlarged by the reciprocal of the projection reduction ratio of the light exposure apparatus shown in FIG.

Therefore, the second pattern AP formed by the second grid G2 which is half the grid interval of the third grid G3 which is the drawing grid of the light exposure mask.
2 can be drawn using the third grid G3 which is a drawing grid.

(Second Embodiment) Next, a second embodiment of the present invention will be described.
The embodiment will be described with reference to FIG. Note that the first to third processes described in the first embodiment are the same and will not be described here.

First, the case where a negative resist is used when drawing a light exposure mask will be described.

FIG. 2A shows the first pattern AP1 described in the first to third processes of the first embodiment.
And the second pattern AP2 and the second grid G2 with the reciprocal of the projection reduction ratio as the enlargement magnification value using the first grid G1.
It is expanded. FIG. 2B shows the second pattern AP2 shown in FIG. 2A as it is, and the second grid G2 alone is further enlarged twice to be converted to a third grid G3. It is.

Next, as shown in FIG. 2C, the upper and lower sides of the second pattern AP2 are respectively
Are moved on the grid lines of the third grid in a direction to reduce the size of the third pattern to obtain a sixth pattern AP6.

Next, as shown in FIG. 2D, a first fine line L1 is arranged from the upper side of the sixth pattern AP6 by one grid interval of the third grid G3.
The second fine lines L2 are respectively arranged one grid interval below the third grid G3 from the lower side of the pattern AP6 to form a seventh pattern AP7. First fine line L1
The size of the second fine line L2 is a size that is not resolved when drawing on the light exposure mask, and the width h is one to several grid intervals of the third grid G3.

When the pattern is drawn on the light exposure mask using the pattern drawing data having the seventh pattern AP7, the electron dose at the upper side and the lower side of the seventh pattern AP7 is equal to the first fine line L1 and the second fine line. Line L2
Increases due to the placement of

When the resist applied at the time of drawing the light exposure mask is a negative resist, the seventh pattern AP7 extends in the long side direction as the electron dose increases.
Therefore, the first fine line L1 and the second fine line L2 arranged outside the seventh pattern AP7 are so arranged that the extension dimension of the resist pattern and the half of the grid interval of the third grid G3 are the same. When the width h is set, the length of the seventh pattern AP7 in the up-down direction is the length before moving the side on the grid line of the third grid G3,
That is, the second pattern AP2 is enlarged by the reciprocal of the projection reduction ratio of the light exposure apparatus. Therefore, the second pattern AP2 formed by the second grid G2 having half the grid interval of the third grid G3, which is the drawing grid, is drawn using the third grid G3, which is the drawing grid of the light exposure mask. be able to.

Next, a case where a positive type resist is used when drawing a light exposure mask will be described.

When the resist applied at the time of drawing the light exposure mask is a positive resist, the resist pattern shrinks as the electron dose increases. Therefore, if the height h of the first fine line L1 and the second fine line L2 is set so that the contracted dimension of the resist pattern and the half of the grid interval of the third grid G3 are the same, the seventh h The length in the vertical direction of the pattern AP7 is the length before moving the side on the grid line of the third grid G3,
That is, the second pattern AP2 is enlarged by the reciprocal of the projection reduction ratio of the light exposure apparatus. Therefore, the second pattern AP2 formed by the second grid G2 having half the grid interval of the third grid G3 as the drawing grid can be drawn using the third grid G3 as the drawing grid.

[0040]

According to the present invention, a pattern to be formed on a light exposure mask using an electron beam lithography apparatus can be drawn in half units of the drawing grid of the electron beam lithography apparatus. The limitation is apparently reduced, and a fine pattern can be formed on the light exposure mask with high accuracy and a fine pattern can be formed on the light exposure mask without lowering the throughput.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a first example of a pattern writing data creation method according to the present invention.
FIG. 7 is a diagram showing a creation procedure of the embodiment, and is a plan view showing how a pattern is converted.

FIG. 2 is a diagram showing a second example of the pattern drawing data creation method according to the present invention.
FIG. 7 is a diagram showing a creation procedure of the embodiment, and is a plan view showing how a pattern is converted.

[Explanation of symbols]

 AP1 first pattern AP2 second pattern AP3 third pattern AP4 fourth pattern AP6 sixth pattern AP7 seventh pattern G1 first grid G2 second grid G3 third grid S1 first fine Space S2 Second fine line L1 First fine line L2 Second fine line

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) G03F 1/08 H01L 21/027

Claims (2)

(57) [Claims] (1)Light exposure equipmentFor light exposure mask used in
The desired patternBy electron beam drawing equipmentTo form
A method for creating pattern drawing data, comprising: forming a circuit pattern of a semiconductor device as the pattern.
A first grid with a predetermined grid spacing to
Designing a first pattern having a predetermined shape using the first grid;Light exposure equipmentInverse of projection reduction ratio of
The number is converted to a second grid enlarged as an enlargement factor, and the first pattern isLight exposure equipmentInverse of projection reduction ratio of
The number is converted to a second pattern enlarged as an enlargement magnification, and the second grid is enlarged twice to form a third grid.
Transforming the second pattern located in the middle of the third grid.
Extend side and move on grid line of third grid
To form a third pattern, and from the side of the third pattern to one grid of the third grid.
When drawing on the light exposure mask inside the lid interval
Size that cannot be resolved by the resist used forAnd the third
From one grid interval to several grid intervals
widthTo form a fourth pattern by inserting a fine space having
SuccessAnd The fine space is used when drawing on the light exposure mask.
When the resist used for the negative type resist,
Regis with decreasing electron dose on the side of the fourth pattern
And the grid of the third grid
The width is equal to half of the interval, The fine space is used when drawing on the light exposure mask.
When the resist used for the positive type resist,
Regis with decreasing electron dose on the side of the fourth pattern
And the grid of the third grid
The width is equal to half the interval, Pattern drawing data
Data creation method. (2)Light exposure equipmentFor light exposure mask used in
The desired patternBy electron beam drawing equipmentTo form
A method for creating pattern drawing data, comprising: forming a circuit pattern of a semiconductor device as the pattern.
A first grid with a predetermined grid spacing to
A first pattern having a predetermined shape is designed using the first grid, and the first grid is inversely projected to the projection reduction ratio of the light exposure apparatus.
The first pattern is converted into a second grid enlarged by using the number as an enlargement magnification, and the first pattern is inverted from the projection reduction ratio of the light exposure apparatus.
The number is converted to a second pattern enlarged as an enlargement magnification, and the second grid is enlarged twice to form a third grid.
Transforming the second pattern located in the middle of the third grid.
Move the edge down on the grid line of the third grid
To form a third pattern, and from the side of the third pattern to one grid of the third grid.
When drawing on the light exposure mask outside the lid interval
Size that cannot be resolved by the resist used forAnd the third
From one grid interval to several grid intervals
widthForming a fourth pattern by inserting fine lines having
And When the fine lines are drawn on the light exposure mask,
If the resist used is a negative resist,
Resist with increasing electron dose on the side of pattern 4
Between the extension dimension of the pattern and the grid of the third grid
The width is equal to half the distance, When the fine lines are drawn on the light exposure mask,
When the resist to be used is a positive resist,
Resist with increasing electron dose on the side of pattern 4
Between the contraction dimension of the pattern and the grid of the third grid
The width is equal to half of the distance, Pattern drawing data
Data creation method.