JPH0934098A - Photomask, manufacture of photomask, formation of pattern, manufacture of semiconductor device, and device for designing mask pattern - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a photomask which prevents an unnecessary pattern from being transferred by preventing an unnecessary projection image from being formed. SOLUTION: This photomask consists of an area which is translucent to at least exposure light and a transparent area, and the phase differences between lights passing through the translucent area and transparent area is substantially 180 deg., and an auxiliary pattern 5 which is transparent and in phase with a main pattern 4 formed out of the transparent area is arranged in an area wherein the angle of the intersection of two desired sides 34 and 35 of the main pattern 4 or their prolongations is <=180 deg. at a translucent phase shift part 6.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a photomask used for manufacturing a semiconductor device or the like, a manufacturing method thereof, a pattern forming method using the same, a semiconductor device manufacturing method and a mask pattern designing apparatus.

[0002]

2. Description of the Related Art A method called a lithography technique for transferring a pattern drawn on a mask onto a substrate to be exposed is widely used for forming patterns of semiconductor integrated circuits and liquid crystal panels. In order to perform this pattern transfer, a reduction projection type projection exposure apparatus that reduces and transfers the pattern on the mask is generally used.

With the recent miniaturization of patterns, the projection exposure apparatus is required to have higher resolution than before. In general, the higher the numerical aperture (NA) of the projection lens or the shorter the wavelength of light used for exposure, the higher the resolution.
However, the method of increasing the NA causes a decrease in the depth of focus during pattern transfer, and shortening the wavelength of light has various restrictions in terms of a light source, an optical system material, or a resist material.

Therefore, an attempt has been made to transfer a fine pattern exceeding the conventional resolution limit by using the current projection exposure apparatus. In Japanese Patent Laid-Open No. 57-62052, a transparent member (phase shifter) for reversing the phase of light is provided in a specific light transmitting portion on a mask, so that the resolving power is greatly improved for a plurality of patterns having periodicity. It has been shown to have improved.

A technique for automatically arranging the phase shifter is reported in VLSI Symposium (1991), and digest of technical papers 95
~ 96 pages (Digest of Technical papers pp.95-96)
Automatic Pattern Generation System For Phase Sh
ifting Mask). The same technique is used in Digest of Papers Micro Process '93, pp. 50-51.
Process '93 pp.50-51) algorithm forephase shift mask design with
Priority on Shifter Placement (Algo
rithm for Phase Shift Mask Design with Priority on
Shifter Placement) and the same book 52-
A CAD system on page 53 Fore designing Phase shifting masks (A CAD
It is also described in a paper entitled System for Designing Phase-Shifting Masks). In addition, the method of determining the mask pattern by inputting the desired projected image shape is
EE, Transaction ON Semiconductor Manufacturing 5 (2) (1992) 1
Pages 38-152 (IEEE Transaction on Semiconductor
Manufacturing, Vol.5, No.2 (1992), pp.138-152) Binary and Phase Shifting Mask Design for Optica
l Lithography).

On the other hand, US Pat. No. 4,360,586 discloses a photomask for controlling the intensity and phase of X-rays or light transmitted through the mask. A similar photomask is also disclosed in Japanese Patent Application Laid-Open No. 04-136854.

In these photomasks, the periphery of a single transparent pattern is made semitransparent, that is, the light-shielding portion of an ordinary photomask is made semitransparent, and a slight phase of light passing through the semitransparent portion is made transparent. The phase of the light passing through the pattern is reversed. That is, light having a sensitivity lower than that of the resist that transfers the pattern is transmitted from the semitransparent portion, and the phases of this light and the light transmitted through the transparent pattern are inverted. Since the light passing through the semi-transparent portion has a phase inverted with respect to the light passing through the transparent pattern which is the main pattern, the phase is inverted at the boundary portion and the light intensity at the boundary portion approaches zero. As a result, the ratio of the intensity of light that has relatively passed through the transparent pattern to the intensity of light at the pattern boundary portion becomes large, and a light intensity distribution with a higher contrast than that of an ordinary light-shielding mask can be obtained. Also doubles. Further, this mask structure can be realized only by changing the conventional light-shielding film to a semitransparent film having a phase inversion function, and the mask fabrication is easy. Hereinafter, such a mask is referred to as a semitransparent phase shift mask.

Also, the digest of papers
Micro Process '93, pp. 44-45 (Digest of Pa
Resolution Imp of pers MicroProcess '93 pp.44 ~ 45)
rovement usinng Auxiliary Pattern Groups in Obliqu
A paper entitled e Illumination Lithography describes that the shape of the projected pattern was improved by providing auxiliary patterns at both ends of multiple periodic patterns of a similar semitransparent phase shift mask. .

[0009]

However, the conventional technique described in Japanese Patent Laid-Open No. 62052/1982 can significantly improve the resolution with respect to a plurality of patterns having periodicity. The method of arranging the phase shifter for a general pattern having no property is not described.

The above-mentioned Digest of Technical Papers, pp. 95-96 (Digest of Technical pa
pers pp.95-96), the above-mentioned digest of papers Micro Process '93.
Pages 50-51 (Digest of Papers MicroProcess '93 p
p.50-51), the prior art described on pages 52-53 of the same book, and IE, Transaction ON Semiconductor Manufacturing 5 (2) (1992) pages 138-152 (IE
EE Transaction on Semiconductor Manufacturing, Vo
All of the conventional techniques described in L.5, No.2 (1992), pp.138-152) relate to a technique for automatically arranging a phase shifter in a light transmitting portion on a mask.

Since the semi-transparent phase shift mask has a slight amount of transmitted light even in a region which should originally be shielded, the transmitted light is emphasized by an interference effect when the pattern approaches, and as a result,
There is a problem that a projected image having a light intensity level that cannot be ignored is formed even in a portion where no pattern originally exists.

Further, the level of the ordinary light-shielding mask is lower than that of the semitransparent phase shift mask, but there is a problem that a projected image is similarly formed on a portion where the pattern originally does not exist due to interference. None of the above-mentioned prior arts describe a method for solving this problem.

Further, the prior arts disclosed in US Pat. No. 4,360,586 and Japanese Patent Laid-Open No. 04-136854 do not solve the problem that the depth of focus of a fine pattern is lowered. Therefore, when manufacturing a miniaturized device, However, there is a problem that the manufacturing yield is lowered due to poor resolution. further,
There is a problem that a projected image is formed in the above-mentioned portion where the original pattern does not exist.

Also, the digest of papers
Micro Process '93, pp. 44-45 (Digest of Pa
The prior art described in pers MicroProcess '93 pp.44-45) can significantly improve the resolution for a plurality of patterns with periodicity, but for general patterns without periodicity. Nothing is listed.

In the conventional technique using the semitransparent phase shift mask described in JP-A-04-136854, the depth of focus of the pattern in the vicinity of the resolution limit cannot be said to be sufficient in the production of an actual device, and the device is miniaturized. There was a problem. See also Digest of Papers Micro Process '93 44.
The conventional technique described on page 45 can improve the resolution with respect to a plurality of patterns having periodicity, but has a problem that it cannot deal with a general pattern having no periodicity. It was

A first object of the present invention is to provide a photomask capable of preventing the generation of unnecessary projected images and the transfer of unnecessary patterns. A second object of the present invention is to provide a pattern forming method using such a photomask. A third object of the present invention is to provide a method of manufacturing a semiconductor device having a fine pattern formed using such a photomask. A fourth object of the present invention is to provide an apparatus for designing a mask pattern for designing such a photomask. A fifth object of the present invention is to provide a method for manufacturing such a photomask. A sixth object of the present invention is to provide a pattern forming method using a photomask manufactured by such a method for manufacturing a photomask.

[0017]

In order to achieve the first object, the photomask of the present invention includes at least a semi-transparent region and a transparent region for the exposure light, and the semi-transparent region. And the phase difference of the light passing through the transparent region is substantially 180 °, and the angle formed by the intersections of the desired two sides of the main pattern of the transparent region or the extension lines thereof is a semi-transparent portion. The transparent auxiliary pattern having the same phase as the main pattern is arranged in an area smaller than 180 degrees.

It is preferable to provide the auxiliary pattern when the angle formed by the intersection of the desired two sides of the main pattern or the extension line thereof is 110 degrees or less at the semitransparent portion. Further, it is preferable that the size of at least one side of the auxiliary pattern is equal to or smaller than the resolution limit of the projection optical system using the photomask. Furthermore, in the position of the center of the auxiliary pattern, the distance D from the above two sides satisfies the relationship of D = dλ / NAm (where NAm is the numerical aperture on the mask side of the projection optical system, λ is the exposure wavelength, and d is the exposure wavelength. Is preferably a value in the range of 0.4 ≦ d ≦ 0.7).

In order to achieve the above first object,
The photomask of the present invention includes a semitransparent region and a transparent region for exposure light, and the phase difference between the semitransparent region and the light passing through the transparent region is substantially 180 °. , A transparent mask having the same phase as the main pattern and a resolution limit of the projection optical system at the position of the photomask corresponding to the position where the interference lights from the two sides of the transparent region having different main patterns strengthen each other. The auxiliary patterns having the following dimensions are arranged.

Further, in order to achieve the first object, the photomask of the present invention includes a semitransparent region and a transparent region for the exposure light, and the semitransparent region and the transparent region. The phase difference of the light passing through such a region is substantially 180 °
And arranging at least two main patterns composed of the transparent regions, and separating the distance S from the center of the two main patterns.
Where S = sλ / NAm (where NAm is the numerical aperture on the mask side of the projection optical system, λ is the exposure wavelength, and s is a coefficient,
At a position satisfying the relationship of (0.8 ≦ s ≦ 1.1)
An auxiliary pattern, which is transparent, has the same phase as the main pattern, and has a size less than the resolution limit of the projection optical system is arranged.

Furthermore, in order to achieve the above first object, the photomask of the present invention includes a semitransparent region and a transparent region for the exposure light, and the semitransparent region and the transparent region. The phase difference of the light passing through such a region is substantially 180 °
And at least two main patterns composed of the transparent regions are arranged, and transparent at the position of the photomask corresponding to the position where the first subpeaks around the respective main peaks projected by the respective main patterns overlap each other. Then, an auxiliary pattern having the same phase as the main pattern and having a dimension not larger than the resolution limit of the projection optical system is arranged.

Furthermore, in order to achieve the first object, the photomask of the present invention includes a semitransparent region and a transparent region for the exposure light, and the semitransparent region and the transparent region. The phase difference of the light passing through such a region is substantially 180 °
And at least two main patterns composed of the transparent areas are arranged, and the transparent pattern is transparent at the position of the photomask corresponding to the position where the diffracted lights from the respective main patterns overlap in the same phase.
An auxiliary pattern having the same phase as the main pattern and having a size not larger than the resolution limit of the projection optical system is arranged. These photomasks have an unnecessary light intensity peak by arranging a transparent auxiliary pattern whose phase difference of transmitted light is the same as the main pattern at the position on the mask corresponding to the position where the unnecessary light intensity peak occurs. Can be canceled. That is, the light having the opposite phase to the unnecessary light intensity peak is incident from the auxiliary pattern to cancel the light. Therefore, the size of the auxiliary pattern needs to be large enough to obtain a sufficient light intensity for canceling the light, but if it is larger than that, it has an adverse effect and is inappropriate.

Further, in order to achieve the above second object,
The pattern forming method of the present invention includes (a) at least a semitransparent region for exposure light and a transparent region, and a phase difference of light passing through the semitransparent region and the transparent region is The angle is substantially 180 °, and the angle between the desired two sides of the main pattern consisting of the transparent region or the intersection of the extended lines thereof is less than 180 ° in the semi-transparent portion, and is transparent to the main region. A photomask on which an auxiliary pattern having the same phase as the pattern is arranged is prepared, and (b) the projection optical system is used to expose the photosensitive thin film on the substrate using the photomask, and (c) the pattern is formed by development. It is the one.

Furthermore, in order to achieve the above-mentioned second object, the pattern forming method of the present invention comprises (a) a semi-transparent region for exposure light and a transparent region, and the semi-transparent region is provided. The position of the photomask corresponding to the position where the phase difference between the region and the light passing through the transparent region is substantially 180 °, and the interference lights from the two sides of the transparent region having different main patterns strengthen each other. A transparent photomask, in which an auxiliary pattern having the same phase as the main pattern and a size equal to or smaller than the resolution limit of the projection optical system is arranged, is prepared, and (b) the projection optical system uses the photomask. The photosensitive thin film on the substrate is exposed to light, and the pattern is formed by (c) development.

Furthermore, in order to achieve the above second object, the pattern forming method of the present invention comprises (a) a semitransparent region and a transparent region for the exposure light, and the semitransparent region is included. The phase difference between the region and the light passing through the transparent region is substantially 180 °, at least two main patterns made of the transparent region are arranged, and the distance S from the center of the two main patterns is S. Where S = sλ / NAm (however, NA
m is the numerical aperture on the mask side of the projection optical system, λ is the exposure wavelength, and s
Is a coefficient, and is transparent at a position satisfying the relationship of 0.8 ≦ s ≦ 1.1), is in phase with the main pattern, and has a size below the resolution limit of the projection optical system. A photomask on which the pattern is arranged is prepared, and (b) the projection optical system is used to expose the photosensitive thin film on the substrate using the photomask.
(C) A pattern is formed by development.

Further, in order to achieve the second object, the pattern forming method of the present invention includes (a) a semitransparent region and a transparent region for the exposure light, and the semitransparent region is used. The phase difference between the region and the light passing through the transparent region is substantially 180 °, at least two main patterns composed of the transparent region are arranged, and the respective main peaks projected by the respective main patterns. A photomask in which a transparent auxiliary pattern having the same phase as the main pattern and having a size equal to or smaller than the resolution limit of the projection optical system is arranged at the position of the photomask corresponding to the position where the first subpeaks around each other overlap each other. Is prepared, and (b) a projection optical system is used to expose the photosensitive thin film on the substrate using the photomask, and (c) development is performed.
It is designed to form a pattern.

Furthermore, in order to achieve the above second object, the pattern forming method of the present invention comprises (a) a semitransparent region and a transparent region for exposure light, and The phase difference between the region and the light passing through the transparent region is substantially 180 °, at least two main patterns made of the transparent region are arranged, and the diffracted light from each of the main patterns has the same phase. At a photomask position corresponding to the overlapping position, a photomask is prepared in which a transparent auxiliary pattern having the same phase as the main pattern and having a size equal to or smaller than the resolution limit of the projection optical system is arranged. An optical system is used to form a pattern by exposing the photosensitive thin film on the substrate using the photomask and developing (c).

Further, in order to achieve the third object,
A method for manufacturing a semiconductor device according to the present invention is (a) used in a projection optical system, including at least a semitransparent region and a transparent region for exposure light, and the semitransparent region and the transparent region. The phase difference of the light passing through is substantially 180 °, and the main pattern is a photomask consisting of the above-mentioned transparent regions, and the transparent auxiliary pattern having the same phase difference of the transmitted light as the above-mentioned transparent regions is used as the mask design. The area determined by the device in the next step is (1) based on the data of the main pattern, the angle formed by the intersections of the desired two sides of the main pattern or the extension lines thereof is smaller than 180 degrees in the semitransparent portion. (2) When an area smaller than 180 degrees is detected, a predetermined auxiliary pattern is determined in the area smaller than 180 degrees at a position that is respectively a predetermined distance from the desired two sides. (B) Photomask The auxiliary pattern determined as the main pattern is formed on a substrate, and (c) a photomask in which the auxiliary pattern determined as the main pattern is formed on a thin film of a photosensitive material on a semiconductor substrate. Projection exposure is performed to form at least a part of the pattern of the semiconductor integrated circuit.

Further, in order to achieve the third object, the method of manufacturing a semiconductor device of the present invention is (a) used in a projection optical system, and at least a region semitransparent to exposure light and transparent. The phase difference between the semi-transparent region and the light passing through the transparent region is substantially 180 °, and the main pattern is that the phase difference between the transmitted light and the photomask formed by the transparent region. Is the same as the transparent region, and a transparent auxiliary pattern is determined by the mask designing device in the next step, and (1) parameters representing the data of at least two main patterns and the optical condition of the projection optical system. The distance S from the center from each main pattern is S = sλ / NAm (where NAm is the numerical aperture on the mask side of the projection optical system, λ is the exposure wavelength, s is a coefficient, and Value in the range of 8 ≦ s ≦ 1.1) (2) When a position satisfying the relation is detected, and (2) a position satisfying the relation is detected, an auxiliary pattern having a size equal to or smaller than the resolution limit of the projection optical system is determined at the position satisfying the relation, and (b) a photomask. The main pattern and the auxiliary pattern are formed on a substrate, and (c) a thin film of a photosensitive material on a semiconductor substrate is projected and exposed using a photomask on which the main pattern and the auxiliary pattern are formed, and semiconductor integration is performed. It is intended to form at least a part of a circuit pattern.

Furthermore, in order to achieve the above third object, the method of manufacturing a semiconductor device of the present invention is (a) used in a projection optical system, and at least a region semitransparent to exposure light and transparent. The phase difference between the semi-transparent region and the light passing through the transparent region is substantially 180 °, and the main pattern is that the phase difference between the transmitted light and the photomask formed by the transparent region. Is the same as the transparent region, and a transparent auxiliary pattern is determined by the mask designing device in the next step, and (1) parameters representing the data of at least two main patterns and the optical condition of the projection optical system. Based on, the projected image light intensity distribution of each main pattern is calculated, and (2) the position where the first subpeaks around the main peak of each main pattern of the projected image light intensity distribution overlap each other is detected. , (3) above When the position is detected, an auxiliary pattern having a size equal to or smaller than the resolution limit of the projection optical system is determined at the position of the photomask corresponding to the position, and (b) the main pattern and the auxiliary pattern are provided on the photomask substrate. And (c) projecting and exposing a thin film of a photosensitive material on a semiconductor substrate using a photomask on which the main pattern and the auxiliary pattern are formed to form at least a part of the pattern of the semiconductor integrated circuit. It is the one.

Furthermore, in order to achieve the above-mentioned third object, the method of manufacturing a semiconductor device of the present invention is (a) used in a projection optical system, and at least a region semitransparent to exposure light and transparent. The phase difference between the semi-transparent region and the light passing through the transparent region is substantially 180 °, and the main pattern is that the phase difference between the transmitted light and the photomask formed by the transparent region. Is the same as the transparent region, and a transparent auxiliary pattern is determined by the mask designing device in the next step, and (1) parameters representing the data of at least two main patterns and the optical condition of the projection optical system. On the basis of the above, the position where the diffracted lights from the respective main patterns are overlapped in the same phase is detected. (2) When the position is detected, the projection optical system is resolved at the position of the photomask corresponding to the position. Compensation for dimensions below the limit A pattern is determined, (b) the main pattern and the auxiliary pattern are formed on a photomask substrate, and (c) the photomask in which the main pattern and the auxiliary pattern are formed on a thin film of a photosensitive material on a semiconductor substrate. Is used for projection exposure to form at least a part of the pattern of the semiconductor integrated circuit.

Further, in order to achieve the third object, the semiconductor device manufacturing method according to the present invention comprises: (a) designing a mask pattern auxiliary pattern of a photomask used for pattern transfer by a projection optical system. By the following steps, and (1) the projection optical system obtains the projection optical system based on the data of at least one main pattern formed on the photomask and the parameters representing the optical conditions of the projection optical system. The projected image light intensity distribution of the main pattern is calculated, and (2) from the projected image light intensity distribution and the main pattern, a region other than the region corresponding to the main pattern is determined in which the light intensity is larger than a predetermined value. (3) When a region larger than the predetermined value is determined, one or more auxiliary patterns are determined in the photomask region corresponding to the region larger than the predetermined value, (B) The main pattern and the determined auxiliary pattern are formed on a photomask substrate, and (c) the photomask in which the main pattern and the determined auxiliary pattern are formed on a thin film of a photosensitive material on a semiconductor substrate. Is used for projection exposure to form at least a part of the pattern of the semiconductor integrated circuit.

The photomask used here includes a semi-transparent region and a transparent region with respect to the exposure light, and the phase difference of the light passing through the semi-transparent region and the transparent region is substantially. It is preferable that the main pattern and the auxiliary pattern are both transparent regions and have the same phase, that is, a halftone phase shift mask.

An example of calculation of the above-mentioned projected image light intensity distribution will be described by taking a halftone phase shift mask as an example. 19A is a plan view of a conventional halftone phase shift mask, FIG. 19B is a sectional view thereof, and FIG.
19C is a diagram showing the amplitude distribution of the mask transmitted light, FIG.
FIG. 19D is a diagram showing the amplitude distribution on the substrate to be exposed, FIG.
(E) is a diagram showing a light intensity distribution on a substrate to be exposed.

As shown in FIGS. 19A and 19B, the halftone phase shift mask includes an optically transparent substrate 42.
And a halftone member 43, and a semitransparent phase shift portion 6 and an open main pattern 4. Light transmitted through the semitransparent phase shifter 6 and the main pattern 4 is shown in FIG.
Like the amplitude distribution 44 shown in FIG. 3, different signs, that is, the phases are mutually inverted. The amplitude distribution obtained on the substrate to be exposed through the projection optical system is a curve 45 shown in FIG. 19D, and the light intensity distribution 47 shown in FIG. can get.

The means for calculating the projected image is to finally obtain the light intensity distribution 47 by inputting the main pattern data and the exposure optical conditions. Here, a negative amplitude peak 46 is generated near the pattern edge, and this appears as a sub peak 48 of the projected image. In particular, when two or more aperture patterns come close to each other, the sub-peaks corresponding to the respective patterns are emphasized, and an unnecessary projected image is obtained at a distance of approximately L1 from the pattern edge.

The position where the unnecessary sub-peak is generated can be easily known by calculating the projected image light intensity distribution of the mask pattern and comparing the image shape predicted from it with the input pattern shape. Here, the sub-peaks generated in the vicinity of the pattern edge are due to the light amplitude having a sign different from that of the light of the main pattern, as described above.

FIG. 20 (a) is a plan view of the halftone phase shift mask of the present invention, FIG. 20 (b) is a sectional view thereof, and FIG. 20 (c) is a view showing an amplitude distribution on a substrate to be exposed.
As shown in FIGS. 20A and 20B, when a new auxiliary pattern 5 is added at a distance of approximately L1 from the edge of the main pattern 4, the negative amplitude of the amplitude distribution 52 shown in FIG. The peak portion and the amplitude distribution 53 of the auxiliary pattern are overlapped with each other, so that it is possible to prevent the occurrence of a sub-peak. Here, it is preferable that the auxiliary pattern 5 has a size such that it is not transferred by itself. Therefore, the width of the auxiliary pattern 5 may be set between approximately 0.05λ / NA and 0.4λ / NA on the substrate to be exposed. Here, λ is the wavelength of the exposure light, and NA is the numerical aperture of the projection lens for exposure. This is 0.05λ / NAm to 0.4λ / on the mask.
NAm (NAm is the numerical aperture on the mask side of the projection lens for exposure).

Further, in order to achieve the third object, the semiconductor device manufacturing method of the present invention comprises: (a) designing a mask pattern auxiliary pattern of a photomask used for pattern transfer by a projection optical system. The device determines the following steps, and (1) based on the data of at least two main patterns formed on the photomask, the outer peripheral line of each main pattern is set to a predetermined distance L.
Respectively, the outer peripheral line is enlarged, and the enlarged outer peripheral line is determined. (2) The position where each enlarged outer peripheral line approaches the predetermined distance M or less is detected, and (3) The close position is detected. At this time, one or a plurality of auxiliary patterns having a predetermined shape are determined at the close positions, (b) the main pattern and the determined auxiliary patterns are formed on the photomask substrate, and (c) Projection exposure is performed on a thin film of a photosensitive material on a semiconductor substrate using a photomask on which the main pattern and the determined auxiliary pattern are formed to form at least a part of a pattern of a semiconductor integrated circuit. is there.

The photomask used here includes a region that is semi-transparent to the exposure light and a region that is transparent, and the phase difference of the light passing through the semi-transparent region and the transparent region is substantially the same. It is preferable that the main pattern and the auxiliary pattern are both transparent regions and have the same phase, that is, a halftone phase shift mask.

The predetermined distance L is k ₁ · λ / NAm
(However, NAm is the numerical aperture on the mask side of the projection optical system,
λ is the wavelength of the exposure light, k ₁ is a coefficient, and 0.4 ≦ k ₁ ≦ 1.1
It is preferable that the value is within the range. The auxiliary pattern has a square shape, a rectangular shape, or a shape in which these are combined, and one side of the square shape and the short side of the rectangular shape have a length of k ₂ · λ / NAm (where NAm is the above-mentioned value). The numerical aperture on the mask side of the projection optical system, λ is the wavelength of the exposure light, k ₂ is a coefficient, and is a value in the range of 0.05 ≦ k ₂ ≦ 0.4).

The formation of the auxiliary pattern of this photomask will be described. The position where the sub-peak shown in FIG. 19 occurs can be predicted from the optical condition. The distance L1 shown in FIG. 19 is approximately 0.55λ / NA. However, since it changes depending on the focus position, the range that L1 can take is about 0.4λ / NA <L1 <1.1λ / NA. This is 0.4λ / NAm at the distance on the mask
Corresponds to <L1 <1.1λ / NAm. Therefore, if the outer peripheral line of the main pattern is moved outward by a predetermined distance L1 to obtain the enlarged outer peripheral line, and the portion where the enlarged outer peripheral line approaches is obtained, that portion is the portion where the sub-peak is emphasized. Is. If you place an auxiliary pattern in that part,
A desired projection image is obtained.

In order to achieve the above-mentioned fourth object,
An apparatus for designing a mask pattern according to the present invention is obtained by the projection optical system based on data of at least one main pattern formed on a photomask used for the projection optical system and parameters representing optical conditions of the projection optical system. From the projection image light intensity distribution and the main pattern, a calculating unit for calculating the projection image light intensity distribution of the main pattern, and a region where the light intensity is larger than a predetermined value in a region other than the region corresponding to the main pattern. And a second determining means for determining one or a plurality of auxiliary patterns in a region of the photomask corresponding to the region larger than the predetermined value when the region larger than the predetermined value is determined. It is composed of a determining means.

Furthermore, in order to achieve the above-mentioned fourth object, the mask pattern designing apparatus of the present invention is based on the data of at least two main patterns formed in the photomask used in the projection optical system. First determining means for determining the enlarged outer peripheral line by moving the outer peripheral lines of the main pattern outward by a predetermined distance L, and a position where each of the enlarged outer peripheral lines approaches a predetermined distance M or less. And a second deciding means for deciding one or a plurality of auxiliary patterns having a predetermined shape at the approaching position when the approaching position is detected. It was done so.

It is preferable that these mask pattern designing devices further include display means for displaying the main pattern, the determined auxiliary pattern, the projected image light intensity distribution and the like. The display means may display the entire area of the photomask or a designated partial area sequentially or simultaneously.

In order to achieve the fifth object,
In the method for manufacturing a photomask of the present invention, (a) an auxiliary pattern of a photomask used for pattern transfer by a projection optical system is determined by a mask pattern designing device in the following steps, and (1) A projection image light intensity distribution of the main pattern obtained by the projection optical system is calculated based on data of at least one main pattern to be formed and a parameter representing an optical condition of the projection optical system, and (2) the projection image From the light intensity distribution and the main pattern, a region other than the region corresponding to the main pattern, where the light intensity is higher than a predetermined value, is determined. (3) When the region higher than the predetermined value is determined, the predetermined value is determined. One or a plurality of auxiliary patterns are determined in the area of the photomask corresponding to an area larger than the value, and (b) the main pattern and the determined above are set on the photomask substrate. It is obtained so as to form a co-pattern.

Further, in order to achieve the fifth object,
In the method for manufacturing a photomask of the present invention, (a) an auxiliary pattern of a photomask used for pattern transfer by a projection optical system is determined by a mask pattern designing device in the following steps, and (1) Based on the data of at least two main patterns to be formed, the outer peripheral line of each main pattern is set to a predetermined distance L.
Respectively, the outer peripheral line is enlarged, and the enlarged outer peripheral line is determined. (2) The position where each enlarged outer peripheral line approaches the predetermined distance M or less is detected, and (3) The close position is detected. At this time, one or a plurality of auxiliary patterns having a predetermined shape are determined at the close positions, and (b) the main pattern and the determined auxiliary patterns are formed on the photomask substrate. Is.

A photomask manufactured by these methods for manufacturing a photomask includes a region that is semi-transparent to exposure light and a region that is transparent, and the light passing through the semi-transparent region and the transparent region is used. It is preferable that the phase difference is substantially 180 °, both the main pattern and the auxiliary pattern are made of transparent regions and have the same phase, that is, a halftone phase shift mask.

In order to achieve the above sixth object,
In the pattern forming method of the present invention, (a) an auxiliary pattern of a photomask used for performing pattern transfer by a projection optical system is determined by a mask pattern designing device in the following steps, and (1) the photomask is formed on the photomask. The intensity distribution of the projected image light of the main pattern obtained by the projection optical system is calculated based on the data of at least one of the main patterns and the parameters representing the optical conditions of the projection optical system. From the intensity distribution and the main pattern, a region other than the region corresponding to the main pattern, where the light intensity is larger than a predetermined value, is determined. (3) When the region larger than the predetermined value is determined, the predetermined value One or more auxiliary patterns are determined in the area of the photomask corresponding to the larger area, and (b) the main pattern and the determined auxiliary patterns are determined on the photomask substrate. Down to form, by (c) a projection optical system, using a photomask in which the main pattern and the determined said auxiliary pattern is formed, is obtained so as to projection exposure.

Furthermore, in order to achieve the sixth object, the pattern forming method of the present invention comprises: (a) an auxiliary pattern of a photomask used for pattern transfer by a projection optical system, which is used for designing a mask pattern. The apparatus determines the following steps, and (1) based on the data of at least two main patterns formed on the photomask, the outer peripheral line of each main pattern is set to a predetermined distance L.
Respectively, the outer peripheral line is enlarged, and the enlarged outer peripheral line is determined. (2) The position where each enlarged outer peripheral line approaches the predetermined distance M or less is detected, and (3) The close position is detected. At this time, one or a plurality of auxiliary patterns having a predetermined shape are determined at the close positions, (b) the main pattern and the determined auxiliary patterns are formed on the photomask substrate, and (c) Projection exposure is performed by using a photomask on which the main pattern and the determined auxiliary pattern are formed by a projection optical device.

[0051]

The undesired light intensity peak is generated at the portion where the phases of the diffracted light from the main pattern and the light passing through the semi-transparent portion coincide with each other, and the lights reinforce each other. In particular, a large light intensity peak occurs in the portion where the diffracted lights from the two patterns overlap in the same phase. Therefore, it is possible to cancel the diffracted light by arranging a transparent auxiliary pattern in which the phase difference of the transmitted light is the same as the main pattern at the position on the mask corresponding to the position where the unnecessary light intensity peak occurs. it can. That is, the unnecessary light can be extinguished by entering the light having a phase opposite to the unnecessary light intensity peak from the auxiliary pattern.

[0052]

【Example】

<Embodiment 1> A first embodiment of the present invention is shown in FIG.
(B) and FIG. 2 demonstrates. FIG. 1A is a plan view of a conventional photomask, and FIG. 1B is a plan view of the photomask of the present invention. 6 is a semi-transparent phase shift part, and 4 is a transparent main pattern. FIG. 2 shows the light intensity distribution obtained on the wafer when a pattern is projected on the wafer using the photomasks of FIGS. 1A and 1B by simulation and shows the position (AB) on the mask. It is a thing. The NA of the projection optical system was 0.52, the exposure wavelength was 365 nm, and the coherency σ of the light source was 0.3. This projection optical system is an example of one condition of the experiment, and other projection optical systems may be used.

In FIG. 2, curve a is the light intensity distribution obtained by the conventional photomask, and curve b is the light intensity distribution obtained by the photomask of the present invention.
In the light intensity distribution obtained by the conventional photomask shown in FIG. 1A, it can be seen that a relative light intensity peak of about 0.3 occurs at the point P1.

In the photomask of the present invention shown in FIG.
A transparent auxiliary pattern 5 was placed in the area 1. As for the position of the auxiliary pattern 5, the distance D from the sides 34 and 35 is 0.3.
8 μm position (at the distance on the mask, the magnification of the lens ×
It becomes 0.38 μm). This distance D is D = dλ
/ NA (D = dλ / NAm on the mask) (where NA is the numerical aperture of the projection optical system, NAm is the numerical aperture of the projection optical system on the mask side, and exposure wavelength is λ, 0.4.
If ≦ d ≦ 0.7), the same effect can be obtained.

The auxiliary pattern 5 is square, and the side length I is 0.3 μm (the length on the mask is the lens magnification × 0.3).
μm), but the invention is not limited to this. I = iλ
/ NAm (however, the numerical aperture on the mask side of the projection optical system is NAm, the exposure wavelength is λ, and 0.3 ≦ i ≦ 0.6)
Similar effects can be obtained as long as the size satisfies the above condition. Also,
The shape is not limited to a square. It may be rectangular or circular. Similar effects can be obtained if the areas are substantially the same.

The pattern was transferred to a normal positive resist coated on the substrate using the above photomask. The exposure amount that can form a resist pattern with the designed size is 240 m.
J / cm ² . In the case of this exposure amount, even if the conventional photomask was used, unnecessary patterns were not formed in the portions other than the main pattern 4. However, the exposure dose was 280 mJ / c
When m ² was set, resist film slippage occurred at a position corresponding to P 1 on the mask. Furthermore, 300 mJ / cm ²
As a result, an unnecessary hole pattern was formed at a position corresponding to P1. On the other hand, the photomask of the present invention is 300
Even with an exposure amount of mJ / cm ² , unnecessary patterns were not formed at positions corresponding to P1 or at other positions.

<Embodiment 2> A second embodiment of the present invention will be described with reference to FIGS. 3 (a), 3 (b) and 4. FIG.
FIG. 3A is a plan view of a conventional photomask, and FIG. 3B is a plan view of the photomask of the present invention. Two transparent square main patterns 4 are arranged in parallel in each of the semitransparent phase shift units 6. The main pattern 4 was a square having a side length of 0.5 μm, and the distance between the pattern centers was 1.1 μm.
This pattern size and arrangement are examples, and the present invention is not limited to this.

In FIG. 4, the light intensity distribution obtained on the substrate when a pattern was projected on the substrate using the photomask of FIG. 3 was obtained by simulation, and the light intensity was shown at each position (CD) on the photomask. It is a thing. The projection optical system lens has an NA of 0.52 and an exposure wavelength of 365n.
m, the coherency σ of the light source is 0.3.

The curve c in FIG. 4 is a conventional photomask, and the curve d.
Is the light intensity distribution obtained by the photomask of the present invention. In the light intensity distribution obtained by the conventional photomask shown in FIG. 3A, it can be seen that a relative light intensity peak of about 0.25 occurs at the points P2 and P3. This position is a position where the first sub-peak around the main peak of the projection image of one main pattern overlaps with the first sub-peak around the main peak of the projection image of the other main pattern.

The photomask of the present invention shown in FIG.
A transparent auxiliary pattern 5 was placed in the portions 2 and P3. The position of the auxiliary pattern 5 is arranged at a position of the same distance S from the centers of the two main patterns 4. The distance S is 0.65 μm, but is not limited to this. The distance S is S = sλ / NA (where NA is the projection optical system, λ is the exposure wavelength, and S is the exposure wavelength).
Is a value satisfying 0.8 ≦ s ≦ 1.1) (on a mask, the numerical aperture on the mask side of the projection optical system is NA).
As m, a position satisfying S = sλ / NAm, where S
Is a value in the range of 0.8 ≦ s ≦ 1.1), the same effect can be obtained.

The auxiliary pattern 5 is square and the side length I is 0.2 μm, but the invention is not limited to this. I = iλ / NA
(However, the numerical aperture of the projection optical system is NA, the exposure wavelength is λ, and 0.2 ≦ i ≦ 0.5), the same effect can be obtained. This is I = i on the mask
λ / NAm (however, the numerical aperture on the mask side of the projection optical system is NAm, the exposure wavelength is λ, and 0.2 ≦ i ≦ 0.5). Further, the shape is not limited to the square. It may be rectangular or circular. Similar effects can be obtained if the areas are substantially the same.

As shown by the curve d in FIG. 4, in the light intensity distribution obtained by the photomask of the present invention, the light intensity at P2 and P3 is small, and the peak obtained by the conventional photomask disappears. I understand.

Patterns were transferred to a normal positive resist coated on the substrate using these photomasks. The exposure amount that can form a resist pattern to the designed size is 270
mJ / cm ² . In the case of this exposure amount, even if the conventional photomask was used, unnecessary patterns were not formed in the portions other than the main pattern 4. However, the exposure dose was 280 mJ /
When it was set to cm ² , resist film slippage occurred at the positions corresponding to P2 and P3 on the mask. Furthermore, 300 mJ /
When it was set to cm ² , unnecessary hole patterns were formed at the positions corresponding to P2 and P3. On the other hand, in the photomask of the present invention, an unnecessary pattern was not formed even at the exposure amount of 300 mJ / cm ² at the positions corresponding to P2 and P3 or at other positions.

This embodiment relates to the pattern arrangement of the semitransparent phase shift mask. A light intensity peak (sub-peak) occurs when the light diffracted from the transparent main pattern portion overlaps with the light passing through the semi-transparent portion in the same phase. When the sub-peaks due to the light diffracted from the plurality of transparent main pattern portions overlap, a stronger light intensity peak occurs. The auxiliary pattern is arranged so as to cancel this stronger light intensity peak.

Although a plurality of sub-peaks occur, if the sub-peak closest to the main pattern peak is the first sub-peak, the light intensity of the first sub-peak is the highest among the sub-peaks. Therefore, since the light intensity at the position where the first sub-peaks of the plurality of main patterns overlap each other is high, the auxiliary pattern may be arranged so as to cancel the light intensity peak at this position.

<Third Embodiment> FIG. 5 is a block diagram showing the arrangement of a mask designing apparatus used in the present invention. This mask designing device comprises a CPU 140, a RAM 141, a storage device 142, a keyboard 148, a display device 149 such as a display, and an output device 150 such as a printer 151. The storage device 142 includes an operating system storage area 143, an auxiliary pattern generation program storage area 144, various parameter storage areas 145, an input main pattern storage area 146, and an auxiliary pattern storage area 147.
Etc. are included.

The RAM 141 is an area for temporarily storing various parameters and main patterns read from the storage device 142, a work area for performing calculations necessary for determining auxiliary patterns,
It has an area for temporarily storing the determined auxiliary pattern.

Various commands to the CPU 140 are issued by the keyboard 148. The display device 149 displays figures such as main patterns and determined auxiliary patterns, a menu screen necessary for instructing the CPU 140, instruction drawings, and the like.
Further, various data are output from the output device 150 as needed.

FIG. 6 is a flow chart showing an example of the processing operation of the mask designing apparatus shown in FIG. The processing operation of this apparatus will be specifically described with reference to this flowchart.

First, one main pattern is selected based on the main pattern data (step S11). If there is a selected main pattern, the angle formed by the intersection of each side or its extension is measured (step S13). It is detected whether there is a region where the angle formed by this intersection is smaller than 180 degrees in the semi-transparent portion, that is, the region outside the main pattern (step S14).
When the area smaller than 180 degrees is not detected, the process returns to step S11 to select another main pattern again. If there is no selected main pattern, that is, if all the main patterns have already been selected, the process ends (step S1).
2).

Returning to step S13, when an area smaller than 180 degrees is detected, the auxiliary pattern data is set so that the auxiliary patterns are arranged at respective positions at predetermined distances from the two outer sides of this area. Determine (Step S1
5) The data of this auxiliary pattern is stored (step S1
6) Then, the process returns to step S11 again to select the next main pattern.

Based on the data of the main pattern and the data of the auxiliary pattern, the main pattern and the auxiliary pattern are formed on the photomask substrate in the same manner as in the first embodiment.

Next, using the photomask on which the main pattern and the auxiliary pattern are formed, in the same manner as in Example 6,
A semiconductor device was manufactured. As in this embodiment, the arrangement of the auxiliary patterns is performed by a mask designing device, a photomask is manufactured based on the data, and a semiconductor device can be manufactured using the photomask.

<Embodiment 4> FIG. 7 is a flow chart showing another example of the processing operation of the mask designing apparatus shown in FIG. Another example of the processing operation of this apparatus will be specifically described with reference to this flowchart.

First, a contour line having a distance S from each main pattern is calculated based on the main pattern data and the parameters of the projection optical system (step S21). S is S = sλ / N
Am (however, NAm is the numerical aperture on the mask side of the projection optical system,
λ is the exposure wavelength, s is a coefficient, and is a value in the range of 0.8 ≦ s ≦ 1.1). Select a certain main pattern (step S2
2) The position where the contour line of this main pattern and the contour lines of other main patterns approach (including crossing) is detected (step S24). Furthermore, consider whether this position is on another main pattern, and if there is such a position, delete it. If there is no position having the distance S, or if any of them is deleted, the process returns to step S22 to select the next main pattern. If there is no selected main pattern, that is,
When all the main patterns have already been selected, the process ends (step S23).

If it is determined in step S25 that there is a position having the distance S, the auxiliary pattern data is determined so that the auxiliary pattern having a predetermined shape is arranged (step S26). The data is stored (step S27), and the process returns to step S22 again to select the next main pattern.

Based on the data of the main pattern and the data of the auxiliary pattern, the main pattern and the auxiliary pattern are formed on the photomask substrate in the same manner as in the first embodiment. Next, a semiconductor device was manufactured in the same manner as in Example 6 by using the photomask on which the main pattern and the auxiliary pattern were formed.

<Embodiment 5> FIG. 8 is a flow chart showing another example of the processing operation of the mask designing apparatus shown in FIG. Another example of the processing operation of this apparatus will be specifically described with reference to this flowchart.

First, the projection optical image distribution of each main pattern is calculated based on the main pattern data and the parameters of the projection optical system (step S31). One of the first subpeaks represented by this projected optical image distribution is selected (step S32). The position where the other first subpeak overlaps this first subpeak is detected (step S34). When no overlapping position is detected, the process returns to step S32 again to select another first sub-peak (step S3).
5). If there is no selected main pattern, that is, if all the main patterns have already been selected, the process ends (step S33).

If there is a position where the two first sub-peaks overlap in step S34, the auxiliary pattern data is determined so that the auxiliary pattern is arranged at that position (step S34).
36), the data of this auxiliary pattern is stored (step S
37) Then, returning to step S32 again, the next first sub-peak is selected.

Next, based on the data of the main pattern and the data of the auxiliary pattern, the main pattern and the auxiliary pattern are formed at the positions corresponding to the above positions of the photomask substrate in the same manner as in the first embodiment. Next, a semiconductor device was manufactured in the same manner as in Example 6 by using the photomask on which the main pattern and the auxiliary pattern were formed.

<Sixth Embodiment> FIG. 9 is a flow chart showing another example of the processing operation of the mask designing apparatus shown in FIG. Another example of the processing operation of this apparatus will be specifically described with reference to this flowchart.

First, the diffracted light from each main pattern is calculated based on the main pattern data and the parameters of the projection optical system (step S41), and the position where the diffracted lights overlap in phase is detected (step S42). ). When such a position is detected (step S43), the auxiliary pattern data is determined so that the auxiliary pattern having a size less than the resolution limit is arranged at the position of the photomask corresponding to the position (step S44). The data of this auxiliary pattern is stored (step S45).

Next, based on the data of the main pattern and the data of the auxiliary pattern, the main pattern and the auxiliary pattern are formed on the photomask substrate in the same manner as in the first embodiment. Next, a semiconductor device was manufactured in the same manner as in Example 6 by using the photomask on which the main pattern and the auxiliary pattern were formed.

As described above, the photomask of the present invention eliminates unnecessary light intensity peaks depending on the pattern arrangement of the main pattern, which is a problem in the conventional photomask, and avoids the transfer of unnecessary patterns. The setting range for the amount of exposure that can be transferred has increased. In other words, it was possible to prevent the occurrence of defects in which unnecessary patterns were transferred. In addition, as a result of forming a semiconductor element using this photomask, it was possible to realize a finer pattern and a smaller element area.

<Embodiment 7> FIG. 10 is a block diagram showing the structure of a mask designing apparatus according to the present invention. This mask designing apparatus includes a CPU 140, a RAM 141, and a storage device 1.
42, keyboard 148, display device 1 such as a display
49, an output device 150 such as a printer 151. The storage device 142 includes an operating system storage area 143 and an auxiliary pattern generation program storage area 14
4, various parameter storage areas 145, an input main pattern storage area 146, an auxiliary pattern storage area 147, and the like.

The RAM 141 is an area for temporarily storing various parameters and main patterns read from the storage device 142, a work area for performing calculations necessary for determining auxiliary patterns,
It has an area for temporarily storing the determined auxiliary pattern.

Various commands to the CPU 140 are issued by the keyboard 148. The display device 149 displays figures such as main patterns and determined auxiliary patterns, a menu screen necessary for instructing the CPU 140, instruction drawings, and the like.
Further, various data are output from the output device 150 as needed.

FIG. 11 is a flow chart showing an example of the processing operation of the mask designing apparatus shown in FIG. The processing operation of this apparatus will be specifically described along this flowchart.

First, in step 51, the main pattern data of the halftone phase shift mask and the parameters of the projection optical system for transferring the mask pattern onto the substrate to be exposed are read. Here, the parameters of the projection optical system include the numerical aperture NA of the projection lens, the mask-side numerical aperture NAm of the projection lens,
The wavelength λ of light used for transfer and the parameter σ representing the degree of coherence.

Next, at step 52, the projected image light intensity distribution obtained by the main pattern is calculated. The projection image light intensity distribution and the pattern on the wafer corresponding to the main pattern are in step 5
3 is displayed. The display area can be selected either whole or specified. At the same time, in step 54, the shapes of the main pattern and the calculated projected image are compared. Here, the shape of the projected image is, for example, a contour obtained by slicing the light intensity distribution at a predetermined intensity level. As a result of the comparison, if the difference between the two is less than the allowable value, the design is finished. However, if the difference is large, that is, if the unnecessary pattern is formed by emphasizing the side lobes, the auxiliary pattern is given in step 55. . Here, the size of the auxiliary pattern was 0.25λ / NA. The projected image is calculated again and compared with the input mask pattern. The auxiliary pattern arrangement and the projection image calculation may be repeated several times so that the difference between the two becomes small. However, in order to prevent this repeated loop from becoming an infinite loop, a predetermined number of times of termination is input in advance.

FIG. 12 shows an example of an input pattern of a halftone phase shift mask. Main patterns 11-1, 11-2, 11-3 and 11-4 are arranged in the semitransparent phase shift unit 6. . This mask has λ = 0.365 μm and NA =
An image obtained when transferred by a projection exposure apparatus with 0.5 and σ = 0.3 was calculated. The results are shown in Figure 13,
An exaggerated side lobe occurred. Therefore, as shown in FIG. 14, the auxiliary patterns 5-1, 5-2, 5-3, 5-4 are formed on the mask corresponding to the portion where the side lobes are generated.
Was generated (the width corresponds to 0.15 μm on the wafer). As a result, the projected image becomes that shown in FIG.
A good pattern was obtained. The obtained mask pattern was stored as pattern data in step 56.

<Embodiment 8> FIG. 27 is a block diagram showing the structure of another example of the mask designing apparatus for performing the processing operation described in Embodiment 7. The main pattern data stored in the file 121 is the input data reading means 12
2, and stored in the file 128. The projection image light intensity calculation means 123 calculates a projection image predicted from the input data, and stores the result in the file 129. The comparison means 125 compares the data stored in the files 128 and 129. At the same time, both are displayed simultaneously or sequentially on the display means 124. If the difference between the two is large, the pattern generating means 126 generates the above auxiliary pattern, adds it to the main pattern, and stores it in the file 128 again. When the difference between the data stored in the files 128 and 129 is within the allowable value, the storage unit 127 outputs the data stored in the file 128 to the file 130 as the finally obtained photomask pattern data.

The operability of the system could be improved by displaying the input pattern, the pattern group including the newly generated pattern, or the projection image calculation result simultaneously or sequentially.

According to this embodiment, the position of the auxiliary pattern can be accurately obtained even if the pattern arrangement and shape are complicated.

<Embodiment 9> FIG. 16 is a flow chart showing an example of the processing operation of the mask designing apparatus shown in FIG. The processing operation of this apparatus will be specifically described along this flowchart.

First, in step 61, the main pattern data of the halftone phase shift mask and the parameters of the projection optical system for transferring the mask pattern onto the substrate to be exposed are read.

Next, at step 62, the outer peripheral line is moved outward by a predetermined distance L so that the input main pattern is enlarged, and a new contour line of the figure is generated. FIG.
In the example shown in, each side of the input main pattern 4 is separated by a distance L in the directions shown by arrows 151, 152, 153, and 154.
Then, the outer peripheral line (hereinafter, referred to as a contour line) 156 of the enlarged graphic is determined. As a result of performing the above processing on the main pattern shown in FIG. 12, the contour lines 156-1, 156-2, 156-3, 156-4 shown in FIG. 18 could be formed.

Returning to FIG. 16, the description will be continued. After generating the enlarged pattern pattern, the position where the contour line approaches within a predetermined distance is detected in step 63 of FIG. The two contour lines may be in contact with each other or may intersect with each other. In step 64, the auxiliary pattern data is determined so that the auxiliary pattern is arranged in that portion. The result is stored in a predetermined file in step 65. In the example shown in FIG. 18, the auxiliary patterns 5-1, 5-2, 5-3, 5-4, 5-5, 5-.
6, 5-7 were given.

Further, as shown in FIGS. 21A, 21B, and 21C, a plan view, a sectional view of the photomask, and a light intensity distribution on the substrate to be exposed, side lobes are generated outside the dense pattern. As you can see, auxiliary pattern 1 by manual operation
4-1 and 14-2 were inserted. In both cases, the pattern size is set to be the same as that of the seventh embodiment. As a result, the same good result as that shown in FIG. 15 was obtained. The auxiliary patterns 14-1 and 14-2 provided by the manual operation are not always necessary, and even if the pattern size of the end portion is set to be slightly larger, the result is practically no problem. The auxiliary patterns 5-7 and the like shown in FIG. 24A are patterns that are long in one direction.
In such a case, as shown in FIG. 24 (b), the auxiliary pattern 5-7 is divided into auxiliary patterns 5-8, 5-9, 5-10, and the intervals between them are set to the width of the auxiliary pattern. The same effect was obtained by arranging them side by side.

<Embodiment 10> FIG. 28 is a block diagram showing the structure of another example of a mask designing apparatus for performing the processing operation described in Embodiment 9.

The file 121 in which the main pattern data is stored, the input data reading means 122, and the output file 130 are the same as those in the system shown in FIG.
The contour line generation means 131 is a means for realizing step 62 shown in FIG.
5 is output. The calculating means 132 is a means for obtaining an area where the contour lines are close to each other, and realizes step 63 shown in FIG. The means for realizing step 64 for determining the auxiliary pattern data is the pattern generating means 133,
The photomask pattern including the auxiliary pattern is stored in the file 130 by the pattern data storage means 134.

<Embodiment 11> The following processing was performed as an example of a processing method for improving the performance of the auxiliary pattern arrangement. First, the adjacency positional relationship of input patterns is calculated prior to the generation of the contour line of the enlarged pattern pattern. If a pattern or a side of a pattern in which no adjacent pattern exists within a distance L '(for example, 1.2λ / NA on the substrate to be exposed) is extracted and the figure has a dimension close to the resolution limit, its width Is increased by a predetermined amount. The dimensions are not changed for the patterns having adjacent patterns. For example, as shown in FIG. 25A, when the pattern 82 has a width close to the resolution limit, the dimension is increased by a predetermined amount to define the figure 83. Similarly, as shown in FIG. 25B, the fine width portion of the pattern 80 is widened to define a graphic 81. Next, the contour lines shown in FIG. 17 are obtained for all input patterns. In the example shown in FIGS. 25A and 25B, contour lines 156-1 and 156-2 are obtained. Finally, the auxiliary pattern is arranged in the portion where the contour lines are close to each other in step 64 shown in FIG.

Further, with respect to the contour line of the pattern in which the size of the input pattern is increased by a predetermined amount, the auxiliary pattern is generated in the area where the adjacent pattern does not exist within the distance L '. Further, when the figure of the input pattern is long in one direction and the width thereof is fine, the contour line corresponding to the apex of the pattern is ignored and excluded from the candidates for arranging the auxiliary pattern. Similarly,
When the size of the input pattern is large in whole or in part and the corresponding contour line does not intersect or approach other contour lines, the auxiliary pattern is excluded from the candidates to be arranged. As a result, the same result as the pattern shown in FIG. 14 was obtained.

<Embodiment 12> FIG. 22 (a) is an example in which relatively large main patterns 8-1 and 8-2 are close to each other at the corners. Further, a light shielding area 59 is set in the peripheral portion.
Immediately after inputting the pattern, the light-shielded area is shown in FIG.
3 (b) is automatically replaced by the fine periodic pattern group 68. Here, the area ratio of the light transmission area and the halftone area of the halftone periodic pattern is √t: 1.
(T is the light intensity transmittance of the halftone portion), and its cycle is a value smaller than the resolution limit of the projection optical system.

When this photomask is used, the main pattern 8-
In addition to the projected images 60 and 61 of 1 and 8-2, unnecessary patterns 62 and 63 are projected by the proximity effect, but unnecessary by arranging the auxiliary patterns 5-1 and 5-2 at two places. I was able to obtain a projection image without patterns.

According to this embodiment, it is not necessary to calculate the projected image, so that the position of the auxiliary pattern can be obtained in a short time.

Example 13 A main pattern and an auxiliary pattern were formed on a photomask substrate in the same manner as in Example 1, using the data determined by the methods in Examples 7, 9, 11 and 12. .

Further, the photosensitive thin film on the semiconductor substrate was subjected to projection exposure by a projection exposure apparatus using the photomask on which the main pattern and the auxiliary pattern were formed. FIG. 26 shows a block diagram of this projection exposure apparatus.

The mask 108 was mounted on the mask mounting table 109 of the projection exposure apparatus, and the pattern was transferred via the projection lens 111 onto the wafer 112 coated with the resist by the usual method. The light emitted from the light source 101 is the concave mirror 10
2, mirrors 103 and 106, fly-eye lens 104,
The mask 108 is illuminated via the diaphragm 104-1 and the lens systems 105 and 107. At this time, the effect as a halftone phase mask could be brought out by controlling the size of the diaphragm 104-1. The wafer 112 is fixed on a wafer mounting table 113, and is further mounted on a stage 114 movable in the optical axis direction of the projection lens 111 and a stage 115 movable in a plane perpendicular to the optical axis. Both stages are controlled by respective drive systems 118 and 119. The mask mounting table 109 was positioned by the mask position control system 110, and the mask 108 and the wafer 112 were aligned by monitoring the wafer position as the position of the mirror 116 by the laser interference system 117. The main control system 120 controls the entire exposure apparatus.
Was performed using. After the pattern transfer, a resist pattern was formed by a normal developing process. As a result, a semiconductor integrated circuit or the like having a fine pattern could be manufactured.

A similar effect can be obtained by using an ordinary chrome mask instead of the halftone phase mask. In particular, when the diaphragm 104-1 of the projection exposure apparatus is narrowed down to make the condition of strong coherence, the effect of the auxiliary pattern arrangement is exhibited well.

In this way, the mask designing device can correct the pattern size and generate the auxiliary pattern for assisting the projection image shape error, so that the pattern shape of the auxiliary pattern can be easily optimized. Therefore, fine pattern transfer is efficiently performed by projection exposure using this photomask, and the manufacture of highly integrated semiconductor devices is facilitated.

[0113]

When a pattern is formed by using the photomask of the present invention, unnecessary pattern transfer can be prevented. Moreover, when a semiconductor device was produced using this photomask, it was possible to realize a finer pattern and a smaller element area. Further, when a photomask was designed using the mask pattern designing apparatus of the present invention, this photomask could prevent the transfer of unnecessary patterns during pattern formation. Further, the photomask as described above could be easily manufactured by the photomask manufacturing method of the present invention.

[Brief description of drawings]

FIG. 1 is a plan view of a conventional photomask and a plan view of a photomask according to a first embodiment of the present invention.

FIG. 2 is a characteristic diagram showing a light intensity distribution of transmitted light of the photomask shown in FIG.

FIG. 3 is a plan view of a conventional photomask and a plan view of a photomask according to a second embodiment of the present invention.

4 is a characteristic diagram showing a light intensity distribution of transmitted light of the photomask shown in FIG.

FIG. 5 is a block diagram showing the configuration of a mask designing apparatus used in the present invention.

FIG. 6 is a flowchart showing an example of the processing operation.

FIG. 7 is a flowchart showing another example of the processing operation.

FIG. 8 is a flowchart showing still another example of the processing operation.

FIG. 9 is a flowchart showing still another example of the processing operation.

FIG. 10 is a block diagram showing the configuration of a mask designing apparatus according to a seventh embodiment of the present invention.

FIG. 11 is a flowchart showing an example of the processing operation.

FIG. 12 is a plan view of a photomask used in Example 7 of the present invention.

FIG. 13 is a projected image light intensity distribution chart.

FIG. 14 is a plan view of a photomask according to a seventh embodiment of the present invention.

FIG. 15 is a projection image light intensity distribution chart.

FIG. 16 is a flowchart showing an example of the processing operation of the mask designing apparatus according to the ninth embodiment of the present invention.

FIG. 17 is a diagram for explaining a mask design according to the ninth embodiment of the present invention.

FIG. 18 is a plan view of a photomask according to Example 9 of the present invention.

FIG. 19 is a plan view of a conventional photomask, a cross-sectional view thereof, an amplitude distribution diagram of transmitted light thereof, an amplitude distribution diagram on an exposed substrate, and a light intensity distribution diagram on the exposed substrate.

FIG. 20 is a plan view of a photomask for explaining the present invention, a cross-sectional view thereof, and an amplitude distribution diagram on a substrate to be exposed.

FIG. 21 is a plan view of a photomask for explaining the present invention, a cross-sectional view thereof, and an amplitude distribution diagram on a substrate to be exposed.

FIG. 22 is a plan view of a photomask for explaining the present invention, a projection image light intensity distribution diagram thereof, and a plan view of a photomask of Example 12 of the present invention.

FIG. 23 is a partial plan view of a photomask according to example 12 of the present invention.

FIG. 24 is a plan view of a pattern portion for explaining the photomask of the present invention.

FIG. 25 is a plan view of a pattern portion for explaining the photomask of the present invention.

FIG. 26 is a block diagram of a projection exposure apparatus used in the present invention.

FIG. 27 is a block diagram showing the configuration of a mask designing apparatus according to an eighth embodiment of the present invention.

FIG. 28 is a block diagram showing the configuration of a mask designing apparatus according to a tenth embodiment of the present invention.

[Explanation of symbols]

 4, 8-1, 8-2, 11-1 to 11-4 ... Main pattern 5, 5-1 to 5-9, 14-1, 14-2 ... Auxiliary pattern 6 ... Semi-transparent phase shift section 34, 35 Side 42 ... Substrate 43 ... Halftone member 44, 52 ... Amplitude distribution 45 ... Curves 46, 53 ... Amplitude peak 47 ... Light intensity distribution 48 ... Subpeak 60, 61 ... Projected image 62, 63, 80, 82 ... Pattern 68 ... Fine periodic pattern 83 ... Graphic 101 ... Light source 102 ... Concave mirror 103, 106 ... Mirror 104 ... Fly-eye lens 104-1 ... Aperture 105, 107 ... Lens system 108 ... Mask 109 ... Mask mounting table 110 ... Mask position control system 111 ... Projection Lens 112 ... Wafer 112 ... Wafer 113 ... Wafer mounting table 114, 115 ... Stage 116 ... Mirror 117 ... Laser interference system 118, 119 ... Drive Dynamic system 120 ... Main control system 121, 128, 129, 130 ... File 122 ... Input data reading means 123 ... Projected image light intensity calculation means 124 ... Display means 125 ... Comparison means 126 ... Pattern generation means 127 ... Storage means 140 ... CPU 141 ... RAM 142 ... Storage device 148 ... Keyboard 149 ... Display device 151 ... Printer 150 ... Output device 142 ... Storage device 143 ... Operating system storage area 144 ... Auxiliary pattern generation program storage area 145 ... Various parameter storage area 146 ... Main pattern storage area Storage area 147 ... Storage area for auxiliary pattern 151, 152, 153, 154 ... Arrows 156, 156-1 to 156-4 ... Contour line

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Akemi Moiwa 1-280, Higashi Koikekubo, Kokubunji, Tokyo Metropolitan Research Laboratory, Hitachi, Ltd. Hitachi, Ltd. Semiconductor Business Division

Claims (31)

[Claims] 1. A region including at least a semi-transparent region and a transparent region for exposure light, wherein a phase difference of light passing through the semi-transparent region and the transparent region is substantially 180 °. In a certain photomask, the desired two sides of the main pattern made of the transparent region or the intersection of the extended lines thereof is transparent to the region which is smaller than 180 degrees in the semitransparent portion and has the same phase as the main pattern. A photo mask characterized in that the auxiliary pattern of is arranged. 2. The photomask according to claim 1, wherein the angle formed by the intersection of desired two sides of the main pattern or extended lines thereof is less than 110 degrees in a semitransparent portion. 3. The photomask according to claim 1, wherein the size of at least one side of the auxiliary pattern is equal to or smaller than the resolution limit of a projection optical system using the photomask. 4. The photomask according to claim 1, wherein the center position of the auxiliary pattern is such that the distance D from the two sides satisfies the relationship of D = dλ / NAm. NAm is a numerical aperture on the mask side of the projection optical system, λ is an exposure wavelength, and d is a coefficient, which is a value in a range of 0.4 ≦ d ≦ 0.7). 5. A photomask including a semitransparent region and a transparent region for exposure light, wherein the phase difference between the light passing through the semitransparent region and the transparent region is substantially 180 °. 2 in which the main pattern consisting of the transparent area is different.
At the position of the photomask that corresponds to the position where the interference light from the side strengthens each other, an auxiliary pattern that is transparent and has the same phase as the main pattern and that is less than the resolution limit of the projection optical system is arranged. A featured photomask. 6. A photomask including a semitransparent region and a transparent region for exposure light, wherein the phase difference between the light passing through the semitransparent region and the transparent region is substantially 180 °. In, at least two main patterns composed of the transparent regions are arranged, and the distance S from the center of the two main patterns is S = sλ / NAm (where NAm is an opening on the mask side of the projection optical system). Is a wavelength, s is a coefficient, s is a coefficient, and is transparent at the position satisfying the relationship of 0.8 ≦ s ≦ 1.1), in phase with the above main pattern, and in the projection optical system. A photomask in which an auxiliary pattern having a size less than the resolution limit is arranged. 7. A photomask including a semitransparent region and a transparent region with respect to exposure light, wherein a phase difference between light passing through the semitransparent region and the transparent region is substantially 180 °. In, at least two main patterns composed of the transparent regions are arranged, and transparent at the position of the photomask corresponding to the position where the first sub-peaks around the respective main peaks projected by the respective main patterns overlap each other. A photomask, characterized in that an auxiliary pattern having the same phase as the main pattern and having a size not larger than the resolution limit of the projection optical system is arranged. 8. A photomask including a semitransparent region and a transparent region for exposure light, wherein the phase difference between the light passing through the semitransparent region and the transparent region is substantially 180 °. In, at least two main patterns composed of the transparent regions are arranged, and at the photomask position corresponding to the position where the diffracted lights from the respective main patterns overlap in the same phase, the main pattern is transparent and has the same phase as the main pattern. And a photomask in which an auxiliary pattern having a size equal to or smaller than the resolution limit of the projection optical system is arranged. 9. (a) At least a semi-transparent region and a transparent region for exposure light are included, and a phase difference of light passing through the semi-transparent region and the transparent region is substantially. 180
And the desired 2 of the main pattern consisting of the transparent areas.
The angle formed by the intersection of the side or its extension is 180 in the semi-transparent part.
Prepare a photomask in which a transparent auxiliary pattern of the same phase as the main pattern is arranged in a region smaller than
(B) A pattern forming method characterized in that a pattern is formed by exposing a photosensitive thin film on a substrate by using a projection optical system using the photomask, and (c) developing. 10. A region which is semi-transparent to exposure light,
Including a transparent region, the phase difference between the semi-transparent region and the light passing through the transparent region is substantially 180 °,
At the position of the photomask corresponding to the position where the interference lights from the two sides of the transparent region having different main patterns intensify each other, it is transparent, in phase with the main pattern, and below the resolution limit of the projection optical system. A photomask on which an auxiliary pattern having the size of 1 is arranged is prepared, and (b) a projection optical system is used to expose a photosensitive thin film on a substrate using the above photomask, and (c) a pattern is formed by development. And a pattern forming method. 11. (a) A region which is semitransparent to exposure light,
Including a transparent region, the phase difference between the semi-transparent region and the light passing through the transparent region is substantially 180 °,
At least two main patterns composed of the transparent regions are arranged, and the distance S from the center of the two main patterns is S = sλ / NAm (where NAm is the numerical aperture on the mask side of the projection optical system, λ is the exposure wavelength, s is a coefficient, and 0.8 ≦
Prepare a photomask in which a transparent auxiliary pattern having the same phase as the main pattern and having a size equal to or smaller than the resolution limit of the projection optical system is arranged at a position satisfying a relationship of (s ≦ 1.1). Then, (b) the projection optical system is used to expose the photosensitive thin film on the substrate using the photomask, and (c) the development is performed.
A pattern forming method comprising forming a pattern. 12. A region (a) which is semitransparent to exposure light,
Including a transparent region, the phase difference between the semi-transparent region and the light passing through the transparent region is substantially 180 °,
At least two main patterns composed of the transparent regions are arranged, and transparent at the position of the photomask corresponding to the position where the first subpeaks around the respective main peaks projected by the respective main patterns overlap each other, Prepare a photomask in which an auxiliary pattern having the same phase as the main pattern and a size equal to or smaller than the resolution limit of the projection optical system is arranged, and (b) the photomask is used by the projection optical system to form a photosensitive thin film on the substrate. A pattern forming method comprising: forming a pattern by exposing to light and (c) developing. 13. (a) A region semi-transparent to exposure light,
Including a transparent region, the phase difference between the semi-transparent region and the light passing through the transparent region is substantially 180 °,
At least two main patterns composed of the transparent regions are arranged, and at the position of the photomask corresponding to the position where the diffracted lights from the respective main patterns overlap in the same phase, the main pattern is transparent and has the same phase as the main pattern, and , Prepare a photomask in which auxiliary patterns with dimensions below the resolution limit of the projection optical system are arranged,
(B) A pattern forming method characterized in that a pattern is formed by exposing a photosensitive thin film on a substrate by using a projection optical system using the photomask, and (c) developing. 14. A method of manufacturing a semiconductor device comprising the steps of: (a) a semi-transparent region which is used in a projection optical system and includes at least a semi-transparent region and a transparent region; , The phase difference of light passing through the transparent region is substantially 180 °, and the main pattern is a photomask made of the transparent region, in which the phase difference of transmitted light is the same as that of the transparent region. The auxiliary pattern is determined by the mask designing device in the next step. (1) Based on the data of the main pattern, the angle formed by the intersections of the desired two sides of the main pattern or the extension lines thereof is a semi-transparent portion. (2) When an area smaller than 180 degrees is detected by (2), the area smaller than 180 degrees is predetermined in each of the predetermined two sides from the desired two sides. Selected auxiliary pattern And (b) forming the auxiliary pattern determined as the main pattern on the photomask substrate, and (c) forming the auxiliary pattern determined as the main pattern on the thin film of the photosensitive material on the semiconductor substrate. Projection exposure is performed using the formed photomask to form at least a part of the pattern of the semiconductor integrated circuit. 15. A method of manufacturing a semiconductor device comprising the steps of: (a) a semi-transparent region used for a projection optical system, which includes at least a semi-transparent region and a transparent region; , The phase difference of light passing through the transparent region is substantially 180 °, and the main pattern is a photomask made of the transparent region, in which the phase difference of transmitted light is the same as that of the transparent region. The auxiliary pattern is determined by the mask designing device in the next step, and (1) based on the data of at least two main patterns and the parameters representing the optical conditions of the projection optical system, the center from each main pattern is determined. From S = sλ / NAm (where NAm is the numerical aperture on the mask side of the projection optical system, λ is the exposure wavelength, s is a coefficient, and is a value in the range of 0.8 ≦ s ≦ 1.1). ), The position satisfying the relationship of When a position satisfying the above relationship is detected, an auxiliary pattern having a size equal to or less than the resolution limit of the projection optical system is determined at a position satisfying the above relationship, and (b) the main pattern and the auxiliary pattern on the photomask substrate. And (c) projection exposure is performed on a thin film of a photosensitive material on a semiconductor substrate using a photomask on which the main pattern and the auxiliary pattern are formed to form at least a part of the pattern of the semiconductor integrated circuit. 16. A method of manufacturing a semiconductor device comprising the steps of: (a) a semi-transparent region which is used in a projection optical system and includes at least a semi-transparent region and a transparent region; , The phase difference of light passing through the transparent region is substantially 180 °, and the main pattern is a photomask made of the transparent region, in which the phase difference of transmitted light is the same as that of the transparent region. The auxiliary pattern is determined by the mask designing device in the next step, and (1) based on the data of at least two main patterns and the parameters representing the optical conditions of the projection optical system, the projected image of each main pattern. Calculating the light intensity distribution, (2) detecting the position where the first sub-peaks around the main peak of each of the main patterns of the projection image light intensity distribution overlap each other, and (3) when the position is detected. , In the above position At the position of the corresponding photomask, an auxiliary pattern having a size equal to or smaller than the resolution limit of the projection optical system is determined, (b) the main pattern and the auxiliary pattern are formed on the photomask substrate, and (c) the semiconductor substrate. Projection exposure is performed on the thin film of the photosensitive material using a photomask on which the main pattern and the auxiliary pattern are formed to form at least a part of the pattern of the semiconductor integrated circuit. 17. A method of manufacturing a semiconductor device comprising the following steps: (a) A semi-transparent region which is used in a projection optical system and includes at least a semi-transparent region and a transparent region. , The phase difference of light passing through the transparent region is substantially 180 °, and the main pattern is a photomask made of the transparent region, in which the phase difference of transmitted light is the same as that of the transparent region. The auxiliary pattern is determined by the mask designing device in the next step, and (1) the diffraction from each of the main patterns is performed based on the data of the at least two main patterns and the parameter representing the optical condition of the projection optical system. (2) When the position where the lights are overlapped with each other in the same phase is detected, an auxiliary pattern having a size equal to or smaller than the resolution limit of the projection optical system is determined at the position of the photomask corresponding to the position. (B) Photomask The main pattern and the auxiliary pattern are formed on a substrate, and (c) a thin film of a photosensitive material on a semiconductor substrate is projected and exposed using a photomask on which the main pattern and the auxiliary pattern are formed, and semiconductor integration is performed. It forms at least part of the pattern of the circuit. 18. A method of manufacturing a semiconductor device comprising the following steps: (a) An auxiliary pattern of a photomask used for pattern transfer by a projection optical system is determined in the next step by an apparatus for mask pattern design. (1) The projection image light intensity distribution of the main pattern obtained by the projection optical system is calculated based on the data of at least one main pattern formed on the photomask and the parameter indicating the optical condition of the projection optical system. (2) From the projected image light intensity distribution and the main pattern, a region other than the region corresponding to the main pattern, where the light intensity is larger than a predetermined value, is determined. When determined, one or more auxiliary patterns are determined in the area of the photomask corresponding to the area larger than the predetermined value, and (b) the main pattern is formed on the photomask substrate. And (c) the thin film of the photosensitive material on the semiconductor substrate is subjected to projection exposure using a photomask on which the main pattern and the determined auxiliary pattern are formed, and semiconductor integration is performed. It forms at least part of the pattern of the circuit. 19. The method of manufacturing a semiconductor device according to claim 18, wherein the photomask includes a semitransparent region and a transparent region with respect to exposure light, and the semitransparent region and the transparent region. The phase difference of the light passing through and is substantially 180
And the main pattern and the auxiliary pattern are both formed of transparent regions and have the same phase. 20. A method of manufacturing a semiconductor device comprising the following steps: (a) An auxiliary pattern of a photomask used for pattern transfer by a projection optical system is determined by a mask pattern designing device in the next step. (1) Based on the data of at least two main patterns formed on the photomask, the outer peripheral line of each main pattern is separated by a predetermined distance L.
Respectively, the outer peripheral line is enlarged, and the enlarged outer peripheral line is determined. (2) The position where each enlarged outer peripheral line approaches the predetermined distance M or less is detected, and (3) The close position is detected. At this time, one or a plurality of auxiliary patterns having a predetermined shape are determined at the close positions, (b) the main pattern and the determined auxiliary patterns are formed on the photomask substrate, and (c) Projection exposure is performed on a thin film of a photosensitive material on a semiconductor substrate using a photomask on which the main pattern and the determined auxiliary pattern are formed to form at least a part of a pattern of a semiconductor integrated circuit. 21. The method of manufacturing a semiconductor device according to claim 20, wherein the photomask includes a semitransparent region and a transparent region with respect to exposure light, and the semitransparent region and the transparent region. The phase difference of the light passing through and is substantially 180
And the main pattern and the auxiliary pattern are both formed of transparent regions and have the same phase. 22. The method of manufacturing a semiconductor device according to claim 20, wherein the predetermined distance L is k ₁ · λ / N.
Am (where NAm is the numerical aperture on the mask side of the projection optical system, λ is the wavelength of the exposure light, k ₁ is a coefficient, and 0.4 ≦ k ₁ ≦
Value in the range of 1.1). 23. The method of manufacturing a semiconductor device according to claim 20, wherein the auxiliary pattern is
In the case of a square or a rectangle or a shape in which these are combined, one side thereof is square, and the length of the short side is rectangular, k ₂ λ / NAm (where NAm is the mask side of the projection optical system). Numerical aperture, λ is the wavelength of exposure light, k ₂ is a coefficient, and is a value in the range of 0.05 ≦ k ₂ ≦ 0.4). 24. Projection of the main pattern obtained by the projection optical system on the basis of data of at least one main pattern formed on a photomask used in the projection optical system and parameters representing optical conditions of the projection optical system. A calculation unit for calculating the image light intensity distribution, and a first region that determines a region where the light intensity is larger than a predetermined value in the region other than the region corresponding to the main pattern, from the projected image light intensity distribution and the main pattern. And a second determining means for determining one or a plurality of auxiliary patterns in the area of the photomask corresponding to the area larger than the predetermined value when the area larger than the predetermined value is determined. A device for designing mask patterns. 25. Based on the data of at least two main patterns formed on a photomask used for a projection optical system, the outer perimeter lines of the respective main patterns are moved outward by a predetermined distance L, respectively, and the outer peripheries are enlarged. First determining means for determining a line, detecting means for detecting a position where each of the enlarged outer peripheral lines approaches a predetermined distance M or less, and when the approaching position is detected, the approaching position A second pattern for determining one or more auxiliary patterns having a predetermined shape.
An apparatus for designing a mask pattern, which comprises: 26. (a) An auxiliary pattern of a photomask used for pattern transfer by a projection optical system is determined by a mask pattern designing device in the next step, and (1) at least 1 is formed on the photomask. The projected image light intensity distribution of the main pattern obtained by the projection optical system is calculated on the basis of the data of the individual main patterns and the parameters representing the optical conditions of the projection optical system, and (2) the projected image light intensity distribution From the main pattern, a region other than the region corresponding to the main pattern is determined to have a light intensity larger than a predetermined value, and (3) when a region larger than the predetermined value is determined, a region larger than the predetermined value. One or more auxiliary patterns are determined in the region of the photomask corresponding to (b), and (b) the main pattern and the determined auxiliary patterns are formed on the photomask substrate. A method for manufacturing a photomask, comprising: 27. The method of manufacturing a photomask according to claim 26, wherein the photomask includes a semi-transparent region and a transparent region with respect to exposure light, and the semi-transparent region and the transparent region. The phase difference of the light passing through is substantially 180
The photomask manufacturing method is characterized in that the main pattern and the auxiliary pattern are both made of transparent regions and have the same phase. 28. (a) An auxiliary pattern of a photomask used for performing pattern transfer by a projection optical system is determined by a mask pattern designing device in the next step, and (1) at least 2 is formed on the photomask. Based on the data of the individual main patterns, the outer peripheral lines of the respective main patterns are moved outward by a predetermined distance L to determine the expanded outer peripheral lines, and (2) the respective expanded outer peripheral lines are (3) When one of a plurality of auxiliary patterns having a predetermined shape is determined at the approached position, the approached position is detected within a predetermined distance M or less, and (3) when the approached position is detected, b) A method of manufacturing a photomask, which comprises forming the main pattern and the determined auxiliary pattern on a photomask substrate. 29. The method of manufacturing a photomask according to claim 28, wherein the photomask includes a semitransparent region and a transparent region for exposure light, and the semitransparent region and the transparent region. The phase difference of the light passing through is substantially 180
The photomask manufacturing method is characterized in that the main pattern and the auxiliary pattern are both made of transparent regions and have the same phase. 30. (a) An auxiliary pattern of a photomask used for pattern transfer by a projection optical system is determined by a mask pattern designing device in the next step, and (1) at least 1 is formed on the photomask. The projected image light intensity distribution of the main pattern obtained by the projection optical system is calculated on the basis of the data of the individual main patterns and the parameters representing the optical conditions of the projection optical system, and (2) the projected image light intensity distribution From the main pattern, a region other than the region corresponding to the main pattern is determined to have a light intensity larger than a predetermined value, and (3) when a region larger than the predetermined value is determined, a region larger than the predetermined value. In the area of the photomask corresponding to, one or more auxiliary patterns are determined, (b) the main pattern and the determined auxiliary patterns are formed on the photomask substrate, (C) A pattern forming method, wherein projection exposure is performed using a photomask on which the main pattern and the determined auxiliary pattern are formed by a projection optical device. 31. (a) An auxiliary pattern of a photomask used for performing pattern transfer by a projection optical system is determined by a mask pattern designing device in the next step, and (1) at least 2 is formed on the photomask. Based on the data of the individual main patterns, the outer peripheral lines of the respective main patterns are moved outward by a predetermined distance L to determine the expanded outer peripheral lines, and (2) the respective expanded outer peripheral lines are (3) When one of a plurality of auxiliary patterns having a predetermined shape is determined at the approached position, the approached position is detected within a predetermined distance M or less, and (3) when the approached position is detected, b) The main pattern and the determined auxiliary pattern are formed on a photomask substrate, and (c) the photomask on which the main pattern and the determined auxiliary pattern are formed by a projection optical device. Used, the pattern forming method characterized by projection exposure.