JP3212643B2 - Phase difference mask - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a phase difference exposure method for forming a fine pattern on a wafer using light exposure and a phase difference mask used for the method.

[0002]

2. Description of the Related Art Conventionally, in order to manufacture a semiconductor integrated circuit,
A resist layer is provided as a photosensitive coating film on the layer to be patterned provided on the substrate, and the resist layer is exposed to the resist layer by a reduced optical projection exposure method using a photomask pattern. Is developed to form a resist pattern, and thereafter, the layer to be patterned is patterned using the resist pattern. For example, a photomask used for patterning performed to connect wiring patterns of respective layers stacked on a substrate of a semiconductor integrated circuit will be described as an example.

FIG. 2A shows an example of a conventional photomask, which is a photomask 30 for a negative resist for forming an opening pattern in an insulating film between wiring layers. In this conventional photomask 30, light-shielding patterns 12a and 12b are selectively provided on a transparent mask substrate 10. The positions at which they are provided correspond to the positions of the opening patterns of the insulating film to be patterned.

FIG. 2B is a schematic sectional view showing a state in which an opening is formed in the resist layer using the mask 30. In this figure, a resist layer 28 is provided on the upper side of the wafer in a state where the insulating layer 26 is provided on the substrate 20. Then, the above-described pattern of the mask 30 is transferred to the resist layer 28 using a reduction exposure apparatus, and subsequently, the resist layer 28 is developed to form an opening 3 in the resist layer 28.
2 (shown in FIG. 2B). Next, the lower insulating layer 26 is formed using the patterned resist layer.
May be patterned using an appropriate etching method.

However, with this conventional mask, the light-shielding patterns 12a, 12a
When the width of b is fine, the contrast of light for exposure at the position of the resist layer is reduced, so that the resolution is reduced. Therefore, the patterning accuracy of the resist layer itself also deteriorates.

Therefore, even if the light shielding patterns 12a and 12b selectively provided on the mask substrate 10 are fine patterns having a small width, a high contrast can be obtained at the position of the resist layer in FIG. A mask 34 having a structure as shown in a sectional view in FIG. In this mask 34,
Light-shielding patterns (hereinafter also referred to as light-shielding portions) 12a, 1
The phase of the light transmitted through the mask substrate 10 around 18b is 18
Phase shifters 13a and 13b that change the phase by 0 degrees, that is, π radians (that is, shift the phase) are provided. This phase shifter is, of course, provided as a film of a suitable transparent material. By using the mask 34, a linear resist pattern having a fine line width to a certain extent or a resist pattern for forming fine contact holes can be formed. This mask 34 is called a phase difference photomask or a phase difference mask.

In any of the conventional masks, when the wafer surface is a flat surface, the surface of the resist layer can be made a flat surface. Therefore, the resist layer can be formed by simultaneous exposure using the same mask over the entire surface of the wafer. Can be patterned substantially as designed.

[0008]

However, if the surface of the wafer is uneven, the layer to be patterned, for example, an insulating layer,
Since each layer such as a wiring pattern metal layer also has an uneven surface, it is difficult to form all patterns with the same resolution or the like by simultaneous exposure using the same mask.

Regarding this point, FIGS.
This will be described with reference to FIG. (A) and (C) of FIG.
The light-shielding pattern 12a of FIG. The center line of these light-shielding portions 12a orthogonal to the mask substrate is indicated by O. An example of patterning a wafer 40 having a stepped portion as shown in FIG. 3 using these masks 30 or 34 will be described.

The wafer 40 is provided on a semiconductor substrate 20 with a selective oxide film (LOCOS oxide film) 21, a patterned first wiring pattern 22, an intermediate insulating layer 24, and an upper side thereof. Metal layer 26. This metal layer is used as the retardation mask 30 or 34
Is a layer to be used for patterning. for that reason,
A resist layer is provided on the metal layer, and the resist layer is patterned using the phase difference mask 30 or.

However, since the resist pattern 28 on the wafer has a step, in the above-mentioned conventional mask, the reduction optical system is used only in the resist surface area above or below the step. However, it is not possible to form a pattern on the entire surface of the mask with high resolution. In addition to this, since the lens used in the reduction optical system causes aberration, the best image forming surface formed by this optical system is shown in FIG.
As shown by a broken line C in FIG. In FIG. 3,
The center O of the light-shielding portion 12a shown in FIGS. 2A and 2C is aligned with the line AA near the resist surface 28a slightly above the step portion of the resist layer 28 and shown in FIGS. It is assumed that an image is being formed. In this case, the distance between the best imaging plane C on the line AA and the surface 26a of the metal layer 26 above the step is D1, but the distance between the best image plane C and the metal layer below the step on the line BB is D1. The distance between the surface 26b of 26 and the best imaging plane C is D2. The height of the step is d1, and the best image plane on the line AA and BB
Assuming that the distance between the best imaging planes C on the line is d2, D2 = D
1 + d1 + d2.

In such an image forming state, the light intensity distribution in the AA line, that is, the light intensity distribution in the region extending right and left around the center O of the light shielding portion is shown by a solid line I1 in FIG. In addition, the minimum value h is obtained at the center O, and increases rapidly as the distance from the center increases. Therefore, as shown by the solid line E1 in FIG. 4B, the contrast also takes a relatively large value even if the distance from the center O is short. On the other hand, when the light intensity distribution on the BB line is superimposed on the light intensity distribution centered on the AA line, the minimum light intensity is j (j> h) as shown by the broken line curve I2. ), And the corresponding contrast gradually increases as the distance from the center increases, as indicated by a broken line E2 in FIG. Conventionally known resists have a contrast of 0.6
It is said that if the level is higher than that, the photosensitivity is sufficient. Accordingly, as shown in FIG. 4, the contrast of the pattern decreases as the size of the pattern becomes smaller, so that a fine pattern having a pattern size of up to k μm which is the resolution limit at the best focus position is formed. It is possible (E1). However, D2 on line BB
In the case of only defocusing, since the contrast with respect to the same pattern size is reduced, the resolution of a resolution-limited pattern is reduced to a pattern size of n μm (n> k).

From this fact, when the resist is exposed by focusing the mask on the upper part of the step when there is a step, the resolution up to the line width of k can be resolved at the upper part of the step. In the lower part of the section, n
It can be seen that resolution can be achieved only with a line width of (> k).

As described above, when a pattern is formed and used on a wafer having a step using the same mask, an image of the mask pattern is formed by focusing on either the lower surface or the upper surface of the step. In addition, a fine-width region having a high contrast is sufficiently resolved, and a beautiful patterning is possible. However, on the other surface out of focus, the contrast is reduced, so that a pattern with a fine width cannot be formed.

An object of the present invention is to use the same mask pattern even when there is a step on the wafer surface or when the best image forming surface is curved due to the lens system of the reduction optical system. An object of the present invention is to provide a phase difference exposure method and a phase difference mask used for the same, which are formed so that a pattern can be formed on the entire surface with high resolution and high precision.

[0016]

[0017]

According to the phase difference mask of the present invention, a mask substrate and an isolated pattern provided on the mask substrate are provided, and a phase shifter is provided on each of the isolated patterns, and the phase shifter is provided from the mask substrate. A phase difference with respect to the phase of the directly transmitted light, and a phase difference mask for subjecting the isolated pattern to phase difference exposure on a photosensitive layer having a step using the phase shift light provided with the phase difference. The pattern is provided so as to be separated from the adjacent isolated pattern by a distance such that light transmitted through the isolated pattern does not interfere with light transmitted through the adjacent isolated pattern provided adjacent to the isolated pattern. (A) a light shielding pattern, (b) a phase shifter, and (c) a phase shift light from the phase shifter has a phase of 1.
And a sub phase shifter that provides a phase difference different by an amount other than 80 ° (π radian). The phase shifter of the isolated pattern is set to an appropriate value within the range of (90 ° ± 10 °). The first phase shifter and the phase difference are (2
70 ° ± 10 °) and a second phase shifter having an appropriate value within the range of 70 ° ± 10 °. The phase difference of the shifter is provided as an appropriate value within a range of (0 ° ± 10 °) or (360 ° ± 10 °) in contact with and surrounding the first phase shifter, and the second phase shifter is provided with the second phase shifter. It is characterized in that it is provided in contact with and around the sub phase shifter. In this case, the phase difference of the first phase shifter is set to an appropriate value in the range of (270 ° ± 10 °), and the phase difference of the second phase shifter is set to an appropriate value in the range of (90 ° ± 10 °). It is good.

[0018]

[0019]

According to the construction of the present invention described above, the photomask has two or more isolated patterns on the photomask substrate. In this case, adjacent isolated patterns are separated from each other by a distance that does not cause interference between the adjacent isolated patterns so that the light for exposing the photosensitive layer to the phase difference of the isolated patterns is provided.

In the structure of the present invention, the image of the isolated pattern is formed by utilizing the interference effect of only the shift light transmitted through the phase shifter provided in the isolated pattern, or by combining the shift light with the isolated pattern. It is obtained by utilizing the effect of interference with the directly transmitted light from the surrounding mask substrate.

Therefore, for example, the best imaging plane which can interfere with a shift light having a phase difference of a multiple of 180 ° (π radian) (including 0 (zero) times in this specification) is referred to as a phase difference of 180 °. By interfering light other than (π radians), the contrast of the image is made larger than before, and the best image forming position is moved closer to the reduction optical system side, shifted in the negative direction, or vice versa. , Far from the reduction optical system, and can be shifted in the plus direction. Normal,
Conditions such as the position and height of the step and the amount of aberration of the optical system are known in advance. Therefore, even when patterning a stepped wafer, if a photomask pattern is formed in consideration of these conditions, the upper and lower steps of the same wafer can be simultaneously exposed by using a single photomask. A fine photomask pattern can be transferred to a photosensitive layer provided in a desired region on the side, for example, a resist layer, thereby forming a fine resist pattern.

[0022]

Embodiments of the present invention will be described below with reference to the drawings. The figures schematically show the shapes, sizes, and arrangements of the components so that the present invention can be understood. In the following description, the structure of the phase difference mask of the present invention and the phase difference exposure method using the same will be described together.

First, before describing the embodiments of the present invention, the basic concept of the present invention will be described. As a photomask pattern of a phase difference mask, an isolated pattern used for patterning a contact hole or a line on a wafer will be described as an example. In order to form a pattern on the wafer, a projected image of the photomask pattern is exposed on a photosensitive layer provided on the wafer using a reduction optical system.
In order to achieve high integration of elements, it is required that the line width of the projected image be as small as possible. Therefore, when projected on the resist layer using a phase difference mask, the center of the contact hole and the line to be formed, corresponding to the center of this isolated pattern,
This isolated pattern is formed so as to obtain the minimum light intensity of the projected image.

FIGS. 5A to 5C show an example of a structure which functions as a light-shielding pattern of a phase difference mask for forming such a pattern having the minimum light intensity. As these light-shielding patterns, for example, a layer of a material that does not transmit light, such as chromium (Cr), for example, provided on a transparent mask substrate 50, that is, an opaque layer 52 (FIG. 5A), a mask substrate 5
A phase shifter 54 (FIG. 5B) that provides a phase difference whose relative phase with respect to the directly transmitted light from 0 is a multiple of π, and provides different phase differences (for example, 90 ° and 270 °). There are a phase shifter edge 56 (FIG. 5 (C)) formed at the boundary where the types of phase shifters 56 and 58 are in contact with each other, and others (not shown).

Next, the isolated pattern gives a phase difference other than a multiple of π (including zero), adjacent to any of the above-mentioned required light-shielding patterns for producing the above-mentioned minimum light intensity portion. That is, the phase shifter 60 that gives an intermediate phase is arranged. Examples of the configuration are shown in FIGS. 6A, 6B and 6C, respectively. The phase shifter 60 that provides the intermediate phase is called a sub phase shifter or an intermediate phase shifter.

With this configuration, the light of the pattern which becomes the central minimum light intensity portion, the light from the intermediate phase shifter and / or the light at the periphery of the pattern interfere with each other. Examples of the light interference will be briefly described with reference to FIGS. 7A, 7B, and 7C. Hereinafter, in the description of this specification, 180 ° (π radian) may be simply referred to as π.

When the relative phase difference between the two phase-shifted lights is a multiple of π, the component of the isolated pattern through which these phase-shifted lights pass is a phase shifter.
When the relative phase difference has a relationship other than a multiple of π,
One component is a phase shifter, and the other component is a sub-phase shifter.

FIG. 7A shows a phase difference mask having a conventional structure. An isolated pattern is a Cr layer (light shielding pattern) 72 on a mask substrate 70 and a sub phase shifter 7 provided around the Cr layer 72.
4 and so on. In this conventional example, the transmitted light A, which is the peripheral light of the isolated pattern, and the intermediate phase light (also referred to as sub-shift light) B interfere with each other. (B) and (C) of FIG.
1 is a structural example of a phase difference mask of the present invention. FIG. 7B
Is an example in which interference is caused by using only the light transmitted through the isolated pattern, and the phase shift lights A1 and A2 from the phase shifters 76 and 78 and the sub shift light B from the sub phase shift light 74 interfere. . The phase difference between the phase shifter lights A1 and A2 is π / 2 and 3π / 2.
And the phase difference of the sub-shift light B is 0 °. Therefore, the relative phase difference between the light beams A1 and A2 is a multiple of π at 180 °. However, the relative phase difference between the light of A1 and A2 and the light of B is 90 °, which is a value other than a multiple of π. FIG. 7C shows an example in which the transmitted light of the isolated pattern and the directly transmitted light interfere with each other. For example, the width of the phase shifter 78 is 1 μm or less, and the phase shifter is shifted from the center of the isolated pattern. This is an example in which the distance to the outer edge of 78 is short, and the directly transmitted light A interferes with the other transmitted lights A1, A2, and B. In this case, the relative phase difference between light A and light B and the relative phase difference between light A1 and light A2 are both 18
0 °, which is a multiple of π. In addition, since the relative phase difference between the light A and each of A1 and A2 and the relative phase difference between the light B and each of A1 and A2 are 90 °, they are values other than multiples of π.

As can be understood from the configuration examples shown in FIGS. 7B and 7C, for example, the interference of -π / 2 and π / 2 phase-shifted light is further reduced. Phase difference exposure using interference of light of three phases that causes light having a relative phase difference with the phase shift light other than π, for example, light directly transmitted from the mask substrate (phase difference of 0 °) to be performed.

Further, for example, a phase shift light having a relative phase difference of -2 / π or 2 / π with respect to a directly transmitted light (phase difference of 0 °) or a phase shift light of π from the mask substrate. And phase difference exposure using interference of light of two phases.

By utilizing the interference effect of light having three or two different phases, the best image forming plane of a pattern for forming a predetermined contact hole or line can be obtained. An image can be formed on a surface different from the best image forming surface of a normal exposure method.

Hereinafter, specific embodiments of the present invention will be sequentially described. In the embodiments described here, a patterning process using a negative resist as a photosensitive layer will be described as an example. However, it should be noted that the present invention can be applied to a positive resist. In each of the drawings, components that perform the same functions are described.
The description will be given with the same reference numerals assigned even if the shape or size changes. In the following description, light directly transmitted from the mask substrate is represented by L1. Also, L2 is light transmitted through the isolated pattern and having a phase difference of 90 ° ± 10 ° with respect to the directly transmitted light. In addition, the light having transmitted through the isolated pattern and having a phase difference of 180 from the directly transmitted light.
The phase shift light of ± 10 ° is represented by L3. Further, L4 is light transmitted through the isolated pattern and having a phase difference of 270 ° ± 10 ° with respect to the directly transmitted light.
L5 is light transmitted through the isolated pattern and having a phase difference of 0 ° (or 360 °) ± 10 ° with respect to the directly transmitted light. Also, in this specification, the best imaging plane of the isolated pattern provided on the phase difference mask of the present invention is formed at a position more distant from the reduction optical system than the position of the normal best imaging plane. In this case, this isolated pattern is referred to as a positive mask pattern. Conversely, if the best imaging plane of the isolated pattern is formed at a position closer to the reduction optical system as compared to the position of the normal best imaging plane, this isolated pattern has a minus shape. It is called a mask pattern. Embodiment 1 FIGS. 1A and 1B are a plan view showing an embodiment of the structure of the phase difference mask of the present invention viewed from an isolated pattern side and taken along the line II. FIG.
In this embodiment, an isolated pattern 110 for forming two contact holes is formed in a transparent mask substrate 100.
Are formed such that light transmitted through the respective isolated patterns 110 does not interfere with each other. Each isolated pattern is formed as a light-shielding pattern, that is, a layer (impermeable layer) 102 of a material that does not transmit light, a first phase shifter 104 provided in contact with the outer periphery thereof, a sub-phase shifter 106 provided in contact with the outer periphery thereof, and furthermore, The second phase shifter 108 is provided in contact with the outer periphery. The light-shielding pattern (also referred to as a light-shielding film or a light-shielding portion) 102 is, for example, a chromium (Cr) layer having a thickness of 1000 A ° (A ° means angstrom) and formed in a square of 0.75 μm square. . This light-shielding pattern functions to minimize the light intensity at the portion of the photosensitive layer corresponding to the center of the contact hole to be formed. In order to reduce the light intensity of the light-shielding pattern 102 more effectively,
First phase shifter 104 and sub phase shifter 106 described above
And a second phase shifter 108. This first phase shifter 104 is 9 with respect to the directly transmitted light L1 from the mask substrate 100 (the phase difference is equivalent to 0 ° ± 10 °) L1.
The shifter gives a phase difference of 0 ° ± 10 °. The sub phase shifter 106 obtains transmitted light having a relative phase difference of ψ ° with the transmitted light from the first phase shifter 104. This ψ ° means a phase difference other than a multiple of π (including zero times). In this case, for example, a relative phase difference of 90 ° ± 10 ° or 270 ° ± 10 ° It may be. The second phase shifter 108 is a shifter for obtaining transmitted light having a relative phase difference of 270 ° ± 10 ° with the transmitted light L1 of the mask substrate 100.

In this embodiment, each shifter 10
Light transmitted through 4, 106 and 108 is L2, L
(Ψ) and L4, and these three lights L2, L (ψ) and L4 having different phases interfere with each other. Therefore, by changing the relative phase difference ψ ° of L (ψ), the best imaging plane of each isolated pattern 110 can be obtained at an arbitrary position different from the best imaging plane in normal exposure. Therefore, a plus or minus type mask pattern can be obtained. Embodiment 2 Next, an embodiment will be described with reference to FIGS. In the isolated pattern of this embodiment, the first phase shifter 104 has a phase difference of (90 ° ± 1) from the directly transmitted light L1.
0 °) (indicated by Q1 in FIG. 8B), and the phase difference of the second phase shifter 108 is (270 ° ± 10 °).
(Indicated by Q2 in FIG. 8B), and the sub-phase shifter 106 has a phase difference of (0 ° ± 10 °) (indicated by Q3 in FIG. 8B). The light shielding pattern of this isolated pattern is 102,
It is formed as a square chrome layer having a thickness of about A ° and a square of 0.75 μm. First phase shifter 104
Has a thickness of about 20
It is formed of a SiO ₂ film of 00 A ° and a width of about 0.5 μm. The sub-phase shifter 106 is in contact with the outer periphery of the first phase shifter and has a thickness of about ± 200 A ° or less (a minus sign means that the substrate 100 is dug to form a groove). SiO ₂ with a width of about 0.5 μm
It is formed with a film. Each of these patterns 104 and 106
The second phase shifter 108 is provided in a region where light interference occurs with the first shift light L2 and the sub-shift light L5 transmitting through the sub phase shifter 106 so as to be in contact with the outer periphery of the sub phase shifter 106. The second phase shifter 108 is formed of a SiO ₂ film with a thickness of about 6000 A °. This second phase shifter 1
08 is transmitted as L4, and therefore, 3
The two lights L2, L5 and L4 having different phases interfere with each other.

The phase difference mask pattern (isolated pattern) thus formed is used for an i-line 1/5 reduction optical system having a numerical aperture NA of 0.50 and a coherence σ of 0.50.
FIG. 8C shows a light intensity distribution according to a change in the focal position of the projected image when projected. The horizontal axis in FIG. 8C indicates the position in the left-right direction about the center of the light-shielding pattern, and the vertical axis indicates the light intensity. In this figure, the light intensity distribution at the best image forming position in the normal exposure method is shown by a curve I.
The light intensity distribution at the position where the focal length is shifted in the minus (-) direction is indicated by the broken line curve II. As can be understood from the curve II, the contrast is low because the light intensity at the central portion of the pattern does not sufficiently decrease. The light intensity distribution at the position where the focal length is shifted in the plus (+) direction is represented by a curve I.
Indicated by II. As can be understood from this curve III,
The light intensity at the center of the pattern is less than 0.1,
For this reason, it can be seen that the best image plane having the highest contrast can be obtained.

An example of patterning a resist layer for forming a contact hole in an actual semiconductor integrated circuit manufacturing process using the isolated pattern of this embodiment will be described with reference to FIG. . In FIG. 9, a phase difference mask is provided on the same mask substrate 100 to obtain a pattern image by interference of the isolated pattern 110 of the embodiment of the present invention and light having a relative phase difference of only a multiple of π of transmitted light. The isolated pattern 112 having the conventional structure is provided at a distance of, for example, 1 μm or more so that the transmitted lights do not interfere with each other. On the other hand, the wafer includes a substrate 120, a field (LOCOS) oxide film 122, a wiring pattern 124, and an interlayer insulating film 126 covering these, and has a step. A resist layer 130 is provided above the stepped interlayer insulating film 126 so that the film thickness is substantially uniform.

In this example, the best image forming plane of the conventional isolated pattern 112 is changed to one of the contact hole forming regions 1.
In this embodiment, the best imaging plane of the isolated pattern 110 is formed near the upper surface of the step of the resist layer on the upper surface 40.
It is formed near the surface on the other side of the step on the other contact hole formation region 142. Note that the center of each isolated pattern is made to coincide with the center of a region where a contact hole is to be formed. After performing the phase difference exposure in this manner, the resist layer 130 is developed to form openings 132 and 134 for etching the contact holes. Third Embodiment FIG. 10A is the same as the phase difference mask of FIG.
Only the differences will be described. In this embodiment, the first phase shifter 104 having the isolated pattern is provided so that the phase difference of the first shift light transmitted therethrough has an appropriate value within the range of (90 ° ± 10 °). Also, the second phase shifter 108
Indicates that the phase difference of the second shift light that has passed therethrough is (270 °
(± 10 °). Then, the sub-phase shifter 106 of the isolated pattern is
The phase difference of the sub-shift light transmitted through this is (180 ° ± 1
0 °). In the figure, respective shift lights are shown as L2, L4 and L3. In this embodiment, a negative type mask pattern is used. Fourth Embodiment FIG. 10B is the same as the phase difference mask of FIG.
Only the differences will be described. In this embodiment, the first phase shifter 104 having an isolated pattern is provided such that the phase difference of the first shift light transmitted therethrough has an appropriate value within a range of (270 ° ± 10 °). Also, the second phase shifter 108
Indicates that the phase difference of the second shift light that has passed therethrough is (90 ° ±
10 °).
Then, the sub-phase shifter 106 having the isolated pattern is provided such that the phase difference of the sub-shift light transmitted therethrough has an appropriate value within the range of (0 ° ± 10 °) or (360 ° ± 10 °). . In the figure, respective shift lights are denoted by L4 and L2.
And L5. In this embodiment, a negative type mask pattern is used. Fifth Embodiment FIG. 11A is the same as the phase difference mask of FIG.
Only the differences will be described. In this embodiment, the first phase shifter 104 having an isolated pattern is provided such that the phase difference of the first shift light transmitted therethrough has an appropriate value within a range of (270 ° ± 10 °). Also, the second phase shifter 108
Indicates that the phase difference of the second shift light that has passed therethrough is (90 ° ±
10 °).
Then, the phase difference of the sub-shift light transmitted through the sub-phase shifter 106 having the isolated pattern is (180 ° ± 10 °).
°) to provide an appropriate value. In the figure, respective shift lights are shown as L4, L2 and L3. In this embodiment, a positive mask pattern is used. Sixth Embodiment FIG. 11B shows that the plus-type isolated pattern described in the second embodiment and the minus-type isolated pattern already described in the fourth embodiment are transmitted through the same mask substrate 100. Are arranged so as not to interfere with each other. The second and first and second phase shifters 10
The relative phase difference between 4 and 108 is 180 ± 10 °, and the direct transmitted light L
The relative phase difference with respect to 1 is ± (90 ° ± 10 °). Seventh Embodiment FIG. 11C shows that the minus isolated pattern described in the third embodiment and the plus isolated pattern already described in the fifth embodiment are transmitted through the same mask substrate 100. Are arranged so as not to interfere with each other. In this case, the first and second phase shifters 1
180 ° ± 10 ° relative phase difference between 04 and 108
The relative phase difference with respect to the directly transmitted light L1 from the mask substrate 100 is ± (90 ° ± 10 °). Example 8 FIG. 12A is the same as the phase difference mask of FIG.
Only the differences will be described. In this embodiment, the first phase shifter 104 having the isolated pattern is provided so that the phase difference of the first shift light transmitted therethrough has an appropriate value within the range of (90 ° ± 10 °). Also, the second phase shifter 108
Indicates that the phase difference of the second shift light that has passed therethrough is (270 °
(± 10 °). Then, the sub-phase shifter 106 of the isolated pattern is
The phase difference of the sub-shift light transmitted through this is (0 ° ± 10
(°) or (360 ° ± 10 °). In this embodiment, the distance Z from the center of the isolated pattern to its outer edge is defined as the phase-shifted light transmitted through the isolated pattern and the directly transmitted light (outer peripheral light) of the mask substrate 100 around the isolated pattern. ) It is set short enough to cause interference with L1.
In this case, the dimension of the second phase shifter 108 on the wafer is preferably set to a width of (2λ / NA) or less.
In the structure of this embodiment, the peripheral light L1 and the shift lights L4, L
The best image is obtained by using the interference of the four lights 2 and L5. In this embodiment, both positive and negative mask patterns can be formed. Ninth Embodiment FIG. 12B is an example of a configuration in which a sub-phase shifter is not provided, unlike the phase difference mask of FIG. Therefore, the first phase shifter 10
4 is provided in contact with the second phase shifter 108 directly. The other constituent materials except the sub phase shifter are the same.
In this embodiment, the first phase shifter 104 having an isolated pattern is used.
And the phase difference of the first shift light transmitted therethrough is (90 ° ±
10 °).
The second phase shifter 108 is provided such that the phase difference of the second shift light transmitted therethrough has an appropriate value within a range of (270 ° ± 10 °). The distance Z from the center of the isolated pattern to its outer edge is determined by the phase-shifted light transmitted through the isolated pattern and the directly transmitted light (also referred to as peripheral light) L1 of the mask substrate 100 around the isolated pattern.
Are set to be short enough to cause interference. Also in this case, the size of the second phase shifter 108 on the wafer is
Preferably, it is provided with a width of (2λ / NA) or less. In the structure of this embodiment, the peripheral light L1 and the shift lights L4 and L2
The best image is obtained by using the interference of the three lights. Even with the structure of this embodiment, both positive and negative mask patterns can be formed. [Embodiment 10] In the structure of this embodiment, in the configurations of Embodiments 2 to 8 described above, each of the first phase shifter 104 and the sub-phase shifter 106 forming the isolated pattern is
The arrangement positions are exchanged with each other, and they are arranged. Twelfth
In (C) of the figure, as an example, the light shielding pattern 102
A sub phase shifter 106 is provided in contact with the outer periphery of the sub phase shifter 106, a first phase shifter 104 is provided around the outer periphery of the sub phase shifter 106, and a second phase shifter 108 is further provided around the outer periphery of the sub phase shifter 106. In this case, each shifter 106, 10
4 and 108 are L5, L2 and L
4, the best imaging plane can be formed shifted in the plus or minus direction from the best imaging plane in a normal exposure method by utilizing the interference of light having three different phases. [Embodiment 11] In the structure of this embodiment, a phase difference mask is used as a mask substrate 100.
And a light-shielding pattern 102, a single phase shifter 114, and a sub-phase shifter 106 provided thereon. FIG. 13A shows a phase shifter 1 forming an isolated pattern.
14 is (180 ° ± 10 °), the phase difference of the sub phase shifter 106 is (90 ° ± 10 °), and FIG. 13B shows the phase shifter 1 forming an isolated pattern.
14 shows an example in which the phase difference is (180 ° ± 10 °) and the phase difference of the sub phase shifter 106 is (270 ° ± 10 °). Further, in the structures of these embodiments, the distance from the center of the isolated pattern, that is, the center of the light-shielding pattern 102 to the outer edge thereof, is determined by each shift light transmitted through the isolated pattern and the mask substrate around the isolated pattern. 100
Is set short enough to interfere with the direct transmitted light (outer light). The transmitted light from the phase difference mask that interferes with each other is L3, L2, and L1 in FIG. 13A, and a positive mask pattern is obtained. In FIG. 13B, L3, L4, and L1 are obtained. Thus, a negative type mask pattern can be obtained. [Embodiment 12] The structure of this embodiment is a structure in which the positions of a phase shifter and a sub-phase shifter which are components of an isolated pattern of the structure of the embodiment 11 are interchanged. That is, the sub-phase shifter 106 is provided on and around the light-shielding pattern 102, and the phase shifter 114 is provided on and around the sub-phase shifter 106. Therefore, the transmitted lights from the phase difference mask that interfere with each other are as shown in FIG.
L2, L3 and L1 to obtain a positive mask pattern, and in FIG. 14B, L4, L3 and L1
And a negative mask pattern is obtained. Embodiment 13 In the structure of the embodiment shown in FIG. 15A, the isolated patterns of the structures of FIGS. 14A and 14B of Embodiment 12 are transmitted through the same mask substrate 100, respectively. Are arranged so as not to interfere with each other. Further, in the structure of the embodiment shown in FIG. 15B, the isolated patterns of the structures of FIGS. 13A and 13B of the eleventh embodiment They are spaced apart so as not to interfere. Both structures have a structure in which positive and negative mask patterns are mixed. [Embodiment 14] The structure of this embodiment is an example in which a light-shielding pattern is not provided in a phase difference mask. In this embodiment, the phase shifter is divided into first and second phase shifters. When the sub phase shifter and the second phase shifter are sequentially arranged around the first phase shifter and around the first phase shifter, the first phase shifter and the second phase shifter are arranged around the sub phase shifter and around the sub phase shifter. There are cases where the shifters are sequentially arranged. These configuration examples are shown in FIGS.
It is shown in (D).

FIG. 16A shows the first phase shifter 104.
And the sub-phase shifter 106
And a second phase shifter 108. The interference light in this case is L2, L5 and L4. FIG. 16B shows the first phase shifter 104 and the sub phase shifter 1 sequentially around the sub phase shifter 106 and around the sub phase shifter 106.
06 and the second phase shifter 108 are provided. The interference light in this case is L5, L4, L5 and L2. FIG. 16C illustrates the sub phase shifter 106 as a center.
A first phase shifter 104 and a second phase shifter 108 are sequentially provided therearound. The interference light in this case is L
3, L4 and L2. FIG. 16D shows the first phase around the sub-phase shifter 106 in order.
A phase shifter 104 and a second phase shifter 108 are provided. The interference light in this case is L5, L2 and L4. As described above, in this embodiment, interference of light having three different phases is used. [Embodiment 15] The structure of this embodiment is an example of a structure in which a light-shielding pattern is not provided, as in Embodiment 14. FIG.
In the embodiment (A), the phase shifter is divided into first and second phase shifters 104 and 108, and the first
With the phase shifter 104 as the center, the second phase shifter 108 and the sub-phase shifter 106 are sequentially arranged around the periphery thereof, and the distance from the center of the isolated pattern to the outer edge thereof is determined by the phase shift light transmitted through the isolated pattern. Is set short enough to interfere with the direct transmission light of the mask substrate on the outer periphery of the isolated pattern. In this structure, the interference between the shift lights L5, L3, L2 and the peripheral light (peripheral light) L1 is used. In the embodiment of FIG. 17B, the phase shifter is configured as a single phase shifter 114, the phase shifter 114 is disposed around the sub-phase shifter 106 around the sub-phase shifter 106, and the phase shifter 114 is positioned from the center of the isolated pattern. The distance to the outer edge is set short enough that the phase-shifted light transmitted through the isolated pattern and the directly transmitted light of the mask substrate around the isolated pattern interfere. Therefore,
In the structure of the embodiment, the shift lights L2 and L3 and the outer circumferential light L1
And use the interference. [Embodiment 16] The structure of this embodiment is different from the phase difference mask of Embodiment 2 in that the auxiliary light-shielding pattern 1 is provided between the first phase shifter 104 and the surrounding second phase shifter 108.
There are 16 hands. In the structure shown in FIG.
Phase shifter 104 and sub-phase shifter 10 adjacent thereto
6, an auxiliary light-shielding pattern (auxiliary light-shielding film) 116,
Provided. In the embodiment shown in FIG. 18B, the auxiliary light-shielding pattern 116 is provided in the sub-phase shifter 106. Regardless of the structure, the shift light L2, L
5 and L4 interference. [Embodiment 17] The structure of the embodiment shown in FIG. 18C is a structure in which no light-shielding pattern is provided. The phase shifter is divided into first and second phase shifters 104 and 108, and the sub phase shifter is divided into first and second sub phase shifters 106a and 106b. 106a as a center, a first phase shifter 104, a second sub-phase shifter 106b, and a second phase shifter 108 are sequentially arranged around the outer periphery thereof, and between the first phase shifter 104 and the second sub-phase shifter 106b. The auxiliary light shielding pattern 116 is provided. In this structure, the interference of the shift lights L3, L4, L3 and L2 is used. [Embodiment 18] The structure of this embodiment is a structure in which no light-shielding pattern is provided. Then, the sub phase shifter 106
And the auxiliary light-shielding pattern 116 between the
Has been arranged. In the structure of FIG. 19A, one phase shifter 114 is provided around the sub phase shifter 106, and an auxiliary light shielding pattern 116 is provided between the two. In this case, the interference of the shift lights L2, L3 and L1 is used. In the structure shown in FIG. 19B, a shifter having a phase difference of 0 ° ± 10 ° is provided at the center or the mask substrate is left alone, and one phase shifter 114 is provided around the shifter. Surrounding sub phase shifter 10
6 are provided, and an auxiliary light shielding pattern 116 is provided between them. In this case, the interference of the shift light L1 or L5, L3, L2 and L1 is used. [Embodiment 19] In the structure of this embodiment, an auxiliary light-shielding pattern is arranged between a sub phase shifter and a second phase shifter around the sub phase shifter. In the structure example shown in FIG. 20A, the first phase shifter 1
04, sub phase shifter 106, auxiliary light shielding pattern 116
And the second phase shifter 108 is sequentially arranged. In this case, the three lights of the shift lights L2, L5 and L4 interfere. In the structure example shown in FIG. 20B, the first phase shifter 104, the sub phase shifter 106, and the second phase shifter 108 are sequentially arranged around the outer periphery of the light shielding pattern 102, and the auxiliary light shielding pattern 116 is 2
The structure is provided in the phase shifter. In this case, three lights of the shift lights L4, L3 and L2 interfere. In the structure example shown in FIG. 20C, the sub phase shifter 106 and the second phase shifter 108 are sequentially arranged around the first phase shifter 104 and around the first phase shifter 104, and the first auxiliary light-shielding is performed. The pattern 116a is disposed between the first phase shifter 104 and the sub phase shifter 106, and the second phase shifter 106 is disposed between the sub phase shifter 106 and the second phase shifter 108.
An auxiliary light shielding pattern 108 is provided. In this case, three lights of the shift lights L2, L3 and L4 interfere. [Embodiment 20] The structure of this embodiment is based on the light shielding pattern 1.
02, and one phase shifter 114,
An auxiliary light-shielding pattern 116 is arranged between the outer periphery and the region of the mask substrate 100. Then, the distance from the center of the isolated pattern to its outer edge is set short enough that the shift lights L2 and L3 transmitted through the isolated pattern and the directly transmitted light L1 of the mask substrate 100 around the isolated pattern interfere. I have. This structure is shown in FIG. [Embodiment 21] In the structure of this embodiment, the components constituting an isolated pattern are not formed so as to surround the entire outer periphery with one element as a center and other elements, but are sequentially contacted. It has a one-dimensional array structure and is used for forming a line-shaped pattern. (A) and (B) of FIG.
Is a plan view seen from the isolated pattern side. In the structure of FIG. 21A, the light shielding pattern 10 is provided on the mask substrate.
The first phase shifter 10 whose relative phase difference with the mask substrate is (90 ° ± 10 °) on both sides of the first
4. A sub phase shifter 106 having a relative phase difference (0 ° ± 10 °) with respect to the mask substrate and a second phase shifter 108 having a relative phase difference (270 ° ± 10 °) with the mask substrate are provided. . In the structure shown in FIG. 21B, the relative phase difference between the mask substrate and the mask substrate is (180 ° ± 10 ° C.).
(°), the first phase shifter 104 having a relative phase difference of (270 ° ± 10 °) between the light-shielding pattern 102 and the mask substrate on both sides of the sub-phase shifter 106 in order.
And relative phase difference with mask substrate (90 ° ± 10 °)
The second phase shifter 108 is provided. Therefore, also in these cases, the best image forming plane of these isolated patterns is formed at a position different from the best image forming plane by the normal exposure method by utilizing interference of light having three different phases. This isolated pattern is used for forming a resist pattern such as a line pattern, a hole pattern, and other patterns. [Embodiment 22] The structure of a phase difference mask of this embodiment is as follows.
Regardless of whether or not each isolated pattern is provided with a light-shielding pattern, when the phase difference of the sub-phase shifter is fixed, the sub-phase constituting each isolated pattern is determined according to the height of the step of the photosensitive layer having the step. The structure is such that each sub-phase shifter is provided by changing the width of the shifter. In the structure of the embodiment shown in FIG. 21C, the width of the sub-phase shifter 106 of two isolated patterns provided on the same mask substrate 100 so as not to interfere with each other is changed. In both isolated patterns, the shift lights L2, L
5 and L4 interference. Embodiment 23 The structure of a phase difference mask of this embodiment is as follows.
Regardless of whether or not each isolated pattern is provided with a light-shielding pattern, when the size of the sub-phase shifter is constant, the sub-phase shifter that forms each isolated pattern according to the height of the step of the photosensitive layer having the step These sub-phase shifters are provided with different relative phase differences with respect to the mask substrate 100. It is used to form a resist pattern such as a line pattern, a hole pattern, and other patterns.

In the structure of the embodiment shown in FIG.
Two isolated pattern sub-phase shifters 1 provided on the same mask substrate 100 so as to be separated from each other so as not to interfere with each other.
06 width is changed. The phase difference of the sub-phase shifter 106 of the isolated pattern on the left side of the drawing is (180 ° + α) ± 10 °
There is. This isolated pattern utilizes the interference of the shift light L2 and the sub-shift lights L6 and L4 having a phase difference of (180 ° + α) ± 10 °. On the other hand, in the isolated pattern on the right side, the phase difference is (180 ° −β) ± 10 °. This isolated pattern has a shift light L2 and a phase difference of (1).
(80 ° -β) The interference of the sub-shifted light L7 and L4 of ± 10 ° is used.

In the embodiment shown in FIG. 22B, the ambient light is used, and the light-shielding pattern 102, one phase shifter 114, and the sub-phase shifter 106 are used. The phase difference of the sub-phase shifter 106 of the isolated pattern on the left side is (90 ° −α) ± 10 °. This isolated pattern utilizes the interference between the shift light L3 and the sub-shift lights L8 and L1 having a phase difference of (90 ° −α) ± 10 °. On the other hand, in the isolated pattern on the right side, the phase difference is (90 ° + β)
± 10 °. This isolated pattern corresponds to the shift light L
3. The interference between the sub-shift lights L9 and L1 having a phase difference of (180 ° −β) ± 10 ° is used. [Embodiment 24] In this embodiment, the sub phase shifter 10
6, and the relative phase difference between the first and second phase shifters 104 and 108 is set to 180 ° ± 10 ° for each isolated pattern. Then, each of the first and second phase shifters 10
The relative phase difference between 4 and 108 with respect to the mask substrate 100 is set according to the height of the step of the photosensitive layer having the step. Here, light having a phase difference of (90 ° −α) ± 10 ° is indicated by L8. Light having a phase difference of (90 ° + β) ± 10 ° is indicated by L9. Light having a phase difference of (270 ° −α) ± 10 ° is denoted by L10. Light having a phase difference of (270 ° + β) ± 10 ° is indicated by L11. The phase difference is (90 ° -α) ± 10 °
Is indicated by L8. In the isolated pattern on the left side of FIG. 23A, the interference of light of L8, L5 and L10 is used,
In the isolated pattern on the right side, interference of light of L9, L5 and L11 is used. In FIG. 23B, the left-side isolated pattern utilizes the interference of light of L3, L10 and L8, and the right-side isolated pattern utilizes the interference of light of L3, L11 and L9. In FIG. 23C, the left-side isolated pattern utilizes the interference of light of L8, L3 and L10, and the right-side isolated pattern utilizes the interference of light of L9, L3 and L11. [Embodiment 25] In this embodiment, an isolated pattern is formed on a mask substrate 100 by setting the relative phase difference between the light shielding pattern 102 and the mask substrate to (90 ° ± 10 °) or (270 °).
(± 10 °) sub phase shifter 106,
A sub-phase shifter 106 is disposed on both sides of the light-shielding pattern 102, and the distance from the center of the isolated pattern to its outer edge is determined by the phase-shifted light transmitted through the isolated pattern and the isolated pattern. Is set short enough to interfere with the directly transmitted light of the mask substrate on the outer periphery. FIG. 24A shows a case where a sub-phase shifter 106 is provided in the left-right direction with the light-shielding pattern 102 as a center.
It is configured as a one-dimensional array. FIG. 24B shows a configuration in which the central light-shielding pattern 102 is surrounded by the sub-phase shifter 106. In this case, when the width of the sub-phase shifter is, preferably, the wavelength of the light to be used is λ,
It is preferable to set it to 0.6λ / NA or more. In the configuration example of FIG. 24C, light interference between L2 and L1 is used. In the configuration example of FIG. 24D, L4 and L4
1 is utilized. [Embodiment 26] In this embodiment, light transmitted through an isolated pattern interferes with light transmitted through an adjacent isolated pattern (not shown) provided adjacent to the isolated pattern. The adjacent isolated pattern is provided apart from the adjacent isolated pattern by a distance not to be used. Then, this isolated pattern is used as the light-shielding pattern 102 and the mask substrate 1.
A sub-phase shifter 106 for providing a phase difference of (90 ° ± 10 °) or (270 ° ± 10 °) with respect to the directly transmitted light of 00 is provided on the mask substrate 100 and configured. The light-shielding pattern 102 is provided on both sides of the sub-phase shifter 106. Further, the distance from the center of the isolated pattern to its outer edge is set short enough to cause interference between the phase-shifted light transmitted through the isolated pattern and the directly transmitted light of the mask substrate around the isolated pattern. The phase difference mask of this embodiment has a one-dimensional array structure as shown in FIG.
As shown in FIG. 3, there is a structure in which the light-shielding pattern 102 surrounds the periphery of the sub-phase shifter 106 as a center. In this case, as shown in FIG. 25C, the light of L2 and the light of L1 (peripheral light) having two different phases interfere with each other. Preferably, the width of the light shielding pattern is 0.6λ.
/ NA or more. Even by the interference of these two light beams having different phases, the relative position between the best imaging surface of the isolated pattern and the best imaging surface by the normal exposure method is shifted to the plus side or the minus side, corresponding to the unevenness of the photosensitive layer, Can be changed in advance. [Embodiment 27] In this embodiment, as in the case of Embodiment 25, an isolated pattern is defined as light transmitted through the isolated pattern and light transmitted through an adjacent isolated pattern provided adjacent to the isolated pattern. The adjacent patterns are separated from each other by a distance that does not interfere with each other.
However, in the case of this embodiment, the isolated pattern is the light shielding pattern 102 and the relative phase difference between them is (90 ° ±
70 °) or (270 ° ± 70 °) first and second
It is composed of phase shifters 104 and 108. The first phase shifter 104 and the second phase shifter 108 are arranged on both sides of the light-shielding pattern 102 in this order. Further, the distance from the center of the isolated pattern to its outer edge is set short enough to cause interference between the phase-shifted light transmitted through the isolated pattern and the directly transmitted light of the mask substrate around the isolated pattern. The phase difference mask of this embodiment has a one-dimensional array structure as shown in FIG. 26 (A) and first and second outer circumferences around a light shielding pattern 102 as shown in FIG. 26 (B). Second
Some have a structure surrounded by the phase shifter light shielding patterns 104 and 108. In this case, as shown in (C) of FIG. 26, light of three different phases L2, L4 and L1 (peripheral light) interferes. Preferably, the width of the light-shielding pattern is set to 0.6λ / NA or more. The relative position between the best imaging plane of the isolated pattern and the best imaging plane by the normal exposure method can also be determined by the interference between the two light beams having different phases.
It can be changed in advance to the plus side or the minus side in accordance with the unevenness of the photosensitive layer. [Embodiment 28] In this embodiment, a light-shielding pattern 102 and a phase shifter 1 constituting components of an isolated pattern are used.
04, 108, 114 and sub-phase shifters 106, 1
The width of at least one of the components 06a and 106b is asymmetric on both sides of the center of the isolated pattern.

The structure shown in FIG. 27A is an example in which the width of the sub phase shifter 106 is changed. In this case, three different phases of light L2, L5 and L4 interfere. FIG.
The structure shown in FIG. 7B is an example in which the height of the sub phase shifter 106 is changed. In this case, light L2 and L12 having four different phases (light having a relative phase difference of (180 ° + β) ± 10 ° (subshift light) with respect to the light directly transmitted through the mask substrate) and L13 (directly transmitted through the square substrate) Light (sub-shift light) having a relative phase difference of (180 ° −α) ± 10 ° with respect to the light and L4 interfere with each other. The structure of FIG. 27C is an example in which the width of one phase shifter 114 is changed. In this case, three different phases of light L2, L3 and L
1 interfere. [Embodiment 29] In this embodiment, the light-shielding patterns 102, 116, and 11 constituting the components of the isolated pattern are provided.
The arrangement interval of the arrangement of 6a and 116b is asymmetric on both sides of the center of the isolated pattern. In this case, in order to optimize the size of the interference light, the width of the light-shielding pattern is preferably set to 0.3λ / NA or less. FIG. 28A shows three lights L2 and L2 having different phases.
5 and L4. FIG. 28B shows three lights L3, L2 and L1 having different phases.
This is a structure that utilizes interference. FIG. 28C shows a structure utilizing interference of light L4, L3 and L2 having three different phases.

It is clear that the invention is not limited to the embodiments described above, but that many modifications and variations are possible. For example, in order to move the best imaging plane from the best imaging plane by the normal exposure method to a position in the plus or minus direction according to the height of the step of the photosensitive layer, the position of the first phase shifter is required. To replace
Alternatively, this can be performed by changing the phase of the sub phase shifter by 180 °. Further, in the above description, the term “shifted light” may be simply used, but this means the first shifted light, the second shifted light, and the sub-shifted light.

[0042]

According to the phase difference mask of the present invention described above, the isolated patterns are formed on the mask substrate at a distance that does not cause mutual interference. Then, the best imaging plane of the isolated pattern is determined by using the interference effect of only the shift light transmitted through the phase shifter provided in the isolated pattern, or by using the shift light and the mask substrate around the isolated pattern. It is obtained by utilizing the effect of interference with direct transmitted light. Then, the width, dimension, position, arrangement order, and the like of the constituent elements of the isolated pattern forming the phase difference mask
Arrangement intervals, combinations, etc., according to the height of the step of the photosensitive layer provided on the wafer, so that the best imaging surface of each isolated pattern can be obtained on the upper surface and the lower surface of the step. A phase difference mask having a plurality of isolated patterns can be designed and formed on one mask substrate in advance. Therefore, when the photosensitive layer provided on the wafer has a stepped portion, an isolated pattern formed on the same phase difference mask is simultaneously exposed in the vicinity of the surface corresponding to the upper side and the surface corresponding to the lower side of the step. Can be exposed with a high contrast ratio. Therefore, if the phase difference mask of the present invention is used, even if the photosensitive layer has a step, the photosensitive layer can be patterned with high resolution and high accuracy. In addition, there is an advantage that only one exposure is required.

[0043]

[Brief description of the drawings]

FIGS. 1A and 1B are explanatory diagrams of a first embodiment of the present invention. FIG.

FIGS. 2A to 2C are explanatory diagrams of a conventional technique.

FIG. 3 is an explanatory diagram of a conventional technique.

FIG. 4 is an explanatory diagram of a conventional technique.

FIGS. 5A to 5C are diagrams respectively showing configuration examples that function as a light-shielding pattern of a phase difference mask for forming a pattern having a minimum light intensity.

FIGS. 6A to 6C are diagrams illustrating a configuration example of a light-shielding pattern and a phase shifter that gives a phase difference other than a multiple of π, that is, gives an intermediate phase.

FIGS. 7A to 7C are diagrams for explaining examples of interference between a pattern having a minimum light intensity and light from an intermediate phase shifter and / or light around the pattern; It is.

FIGS. 8A to 8C are explanatory diagrams of a second embodiment of the present invention.

FIG. 9 is an explanatory diagram of a patterning example of the present invention.

FIGS. 10A and 10B are explanatory diagrams of the third and fourth embodiments of the present invention.

FIGS. 11A to 11C are explanatory diagrams of fifth, sixth, and seventh embodiments of the present invention.

FIGS. 12A to 12C are explanatory views of eighth, ninth, and tenth embodiments of the present invention.

FIGS. 13A and 13B are explanatory diagrams of an eleventh embodiment of the present invention.

FIGS. 14A and 14B are explanatory diagrams of a twelfth embodiment of the present invention.

FIGS. 15A and 15B are explanatory diagrams of a thirteenth embodiment of the present invention.

FIGS. 16A to 16D are explanatory views of a fourteenth embodiment of the present invention.

FIGS. 17A and 17B are explanatory diagrams of a fifteenth embodiment of the present invention.

FIGS. 18A and 18B are explanatory diagrams of a sixteenth embodiment of the present invention, and FIG. 18C is an explanatory diagram of a seventeenth embodiment of the present invention.

FIGS. 19A and 19B are explanatory diagrams of an eighteenth embodiment of the present invention.

FIGS. 20 (A) to (C) and (D) are explanatory views of the nineteenth and twentieth embodiments of the present invention.

FIGS. 21 (A) and (B) are explanatory diagrams of a twenty-first embodiment of the present invention, and FIG. 21 (C) is an explanatory diagram of a twenty-second embodiment of the present invention.

FIGS. 22A and 22B are explanatory diagrams of a twenty-third embodiment of the present invention.

FIGS. 23A to 23C are explanatory diagrams of a twenty-fourth embodiment of the present invention.

FIGS. 24A to 24D are explanatory diagrams of a twenty-fifth embodiment of the present invention.

FIGS. 25A to 25C are explanatory diagrams of a twenty-sixth embodiment of the present invention.

FIGS. 26A to 26C are explanatory diagrams of a twenty-seventh embodiment of the present invention.

FIGS. 27A to 27C are explanatory diagrams of a twenty-eighth embodiment of the present invention.

FIGS. 28A to 28C are explanatory diagrams of a twenty-ninth embodiment of the present invention.

[Explanation of symbols]

100: mask substrate, 102: light shielding pattern 104: first phase pattern 106: sub phase pattern 106a: first sub phase shifter 106b: da
i2 sub phase shifter 108: second phase shifter 110: isolated pattern 112: conventional isolated pattern 114: phase shifter 116: auxiliary light shielding pattern 116a: first
Auxiliary light shielding pattern 116b: Second auxiliary light shielding pattern

────────────────────────────────────────────────── ─── Continued on the front page (56) Reference European Patent Application Publication 395425 (EP, A2) (58) Fields investigated (Int. Cl. ⁷ , DB name) H01L 21/027 G03F 1/08

Claims (12)

(57) [Claims] A mask substrate; and an isolated pattern provided on the mask substrate. A phase shifter is provided on each of the isolated patterns to provide a phase difference with respect to the phase of directly transmitted light from the mask substrate. In a phase difference mask for subjecting the isolated pattern to phase difference exposure on a photosensitive layer having a step using the phase shift light given the phase difference, the light transmitted through the isolated pattern is converted to the isolated pattern. (A) a light-shielding pattern; and (b) a phase shifter. The isolated pattern is provided so as to be separated from the adjacent isolated pattern by a distance that does not interfere with light transmitted through the adjacent isolated pattern. (C) The phase shift light from the phase shifter has a phase of 18
A sub-phase shifter that provides a phase difference that differs by an amount other than 0 ° (π radian).
(° ± 10 °) and a second phase shifter having an appropriate value within the range of (270 ° ± 10 °). The first phase shifter is provided in contact with and surrounding the light-shielding pattern, and the phase difference of the sub-phase shifter of the isolated pattern is set to (0
(° ± 10 °) or (360 ° ± 10 °) as an appropriate value in contact with and surrounding the first phase shifter, and providing the second phase shifter in contact with the sub-phase shifter. A phase difference mask provided around. 2. A mask substrate, comprising an isolated pattern provided on the mask substrate, and a phase shifter provided on each of the isolated patterns to provide a phase difference with respect to the phase of directly transmitted light from the mask substrate. In a phase difference mask for subjecting the isolated pattern to phase difference exposure on a photosensitive layer having a step using the phase shift light given the phase difference, the light transmitted through the isolated pattern is converted to the isolated pattern. (A) a light-shielding pattern; and (b) a phase shifter. The isolated pattern is provided so as to be separated from the adjacent isolated pattern by a distance that does not interfere with light transmitted through the adjacent isolated pattern. (C) The phase shift light from the phase shifter has a phase of 18
A sub-phase shifter that provides a phase difference that differs by an amount other than 0 ° (π radian).
(° ± 10 °) and a second phase shifter having an appropriate value within the range of (270 ° ± 10 °). The first phase shifter is provided in contact with and surrounding the light-shielding pattern, and the phase difference of the sub-phase shifter of the isolated pattern is set to (1
80 ° ± 10 °) as the appropriate value within the first range.
A phase difference mask provided in contact with and surrounding the phase shifter, and wherein the second phase shifter is provided in contact with and surrounding the sub-phase shifter. 3. A mask substrate, and an isolated pattern provided on the mask substrate, wherein a phase shifter is provided on each of the isolated patterns to give a phase difference to the phase of directly transmitted light from the mask substrate. In a phase difference mask for subjecting the isolated pattern to phase difference exposure on a photosensitive layer having a step using the phase shift light given the phase difference, the light transmitted through the isolated pattern is converted to the isolated pattern. (A) a light-shielding pattern; and (b) a phase shifter. The isolated pattern is provided so as to be separated from the adjacent isolated pattern by a distance that does not interfere with light transmitted through the adjacent isolated pattern. (C) The phase shift light from the phase shifter has a phase of 18
A sub-phase shifter that provides a phase difference different by an amount other than 0 ° (π radian).
(0 ° ± 10 °) and a second phase shifter having an appropriate value within the range of (90 ° ± 10 °). Providing the first phase shifter in contact with and surrounding the light-shielding pattern, and setting the phase difference of the sub-phase shifter of the isolated pattern to (0
(° ± 10 °) or (360 ° ± 10 °) as an appropriate value in contact with and surrounding the first phase shifter, and providing the second phase shifter in contact with the sub-phase shifter. A phase difference mask provided around. 4. A mask substrate and an isolated pattern provided on the mask substrate, and a phase shifter is provided on each of the isolated patterns to give a phase difference to the phase of directly transmitted light from the mask substrate. In a phase difference mask for subjecting the isolated pattern to phase difference exposure on a photosensitive layer having a step using the phase shift light given the phase difference, the light transmitted through the isolated pattern is converted to the isolated pattern. (A) a light-shielding pattern; and (b) a phase shifter. The isolated pattern is provided so as to be separated from the adjacent isolated pattern by a distance that does not interfere with light transmitted through the adjacent isolated pattern. (C) The phase shift light from the phase shifter has a phase of 18
A sub-phase shifter that provides a phase difference different by an amount other than 0 ° (π radian).
(0 ° ± 10 °) and a second phase shifter having an appropriate value within the range of (90 ° ± 10 °). Providing the first phase shifter in contact with and surrounding the light-shielding pattern, and setting the phase difference of the sub-phase shifter of the isolated pattern to (1
As an appropriate value within the range of 80 ° ± 10 °), the first phase shifter is provided around the outer periphery thereof in contact with the first phase shifter, and the second phase shifter is provided around the outer periphery thereof in contact with the sub phase shifter. Phase difference mask. 5. An isolated pattern according to claim 1 and an isolated pattern according to claim 3 on the same mask substrate.
A phase difference mask characterized in that light transmitted therethrough is disposed so as not to interfere with each other. 6. The isolated pattern according to claim 2 and the isolated pattern according to claim 4 on the same mask substrate.
A phase difference mask characterized in that light transmitted therethrough is disposed so as not to interfere with each other. 7. The first phase shifter and the sub-phase shifter constituting the isolated pattern according to any one of claims 1 to 4, wherein the first phase shifter and the sub-phase shifter are arranged so that their arrangement positions are interchanged. A phase difference mask characterized by comprising: 8. A mask substrate, and an isolated pattern provided on the mask substrate. Each of the isolated patterns is provided with a phase shifter to provide a phase difference with respect to the phase of directly transmitted light from the mask substrate. In a phase difference mask for subjecting the isolated pattern to phase difference exposure on a photosensitive layer having a step using the phase shift light given the phase difference, the light transmitted through the isolated pattern is converted to the isolated pattern. Are provided so as to be separated from the adjacent isolated pattern by a distance that does not interfere with light transmitted through the adjacent isolated pattern provided adjacent to the isolated pattern, wherein the isolated pattern is: (a) a light-shielding pattern; (180 ° ± 10 °) phase shifter; and (c) the phase difference is (90 ° ± 10 °) or (27 °).
0 ° ± 10 °), and the distance from the center of the isolated pattern to its outer edge is determined by the phase shift light transmitted through the isolated pattern and the direct transmission of the mask substrate around the isolated pattern. It is set to be short enough to interfere with light, and the isolated pattern is provided around the outer periphery of the phase shifter in contact with the light-shielding pattern, and the sub-phase shifter is provided around the outer periphery of the phase shifter in contact with the light-shielding pattern. A phase difference mask, wherein the phase difference mask is provided. 9. A mask substrate and an isolated pattern provided on the mask substrate, and a phase shifter is provided on each of the isolated patterns to give a phase difference to the phase of directly transmitted light from the mask substrate. In a phase difference mask for subjecting the isolated pattern to phase difference exposure on a photosensitive layer having a step using the phase shift light given the phase difference, the light transmitted through the isolated pattern is converted to the isolated pattern. Are provided so as to be separated from the adjacent isolated pattern by a distance that does not interfere with light transmitted through the adjacent isolated pattern provided adjacent to the isolated pattern. (180 ° ± 10 °) phase shifter; and (c) the phase difference is (90 ° ± 10 °) or (27 °).
0 ° ± 10 °), and the distance from the center of the isolated pattern to its outer edge is determined by the phase shift light transmitted through the isolated pattern and the direct transmission of the mask substrate around the isolated pattern. It is set to be short enough to interfere with light, and the isolated pattern is provided around the sub-phase shifter in contact with the light-shielding pattern and around the sub-phase shifter. A phase difference mask, wherein the phase difference mask is provided. 10. The isolated pattern according to claim 8 and the isolated pattern according to claim 9 are arranged on the same mask substrate so as to be separated from each other so that light passing therethrough does not interfere with each other. Phase difference mask. 11. A mask substrate, and an isolated pattern provided on the mask substrate, wherein a phase shifter is provided on each of the isolated patterns to give a phase difference to the phase of directly transmitted light from the mask substrate. In a phase difference mask for subjecting the isolated pattern to phase difference exposure on a photosensitive layer having a step using the phase shift light given the phase difference, the light transmitted through the isolated pattern is converted to the isolated pattern. (B) a light-shielding pattern; (b) a phase shifter; and (b) a light-shielding pattern. (C) The phase shift light from the phase shifter has a phase of 18
A sub-phase shifter that provides a phase difference that differs by an amount other than 0 ° (π radian).
(± 10 °) and a second phase shifter having an appropriate value of the phase difference of (270 ° ± 10 °). The phase shifter is a sub phase shifter having a phase difference of (0 ° ± 10 °), and the first phase shifter, the sub phase shifter, and the second phase shifter are sequentially and one-dimensionally arranged on both sides of the light shielding pattern. A phase difference mask characterized by the following. 12. A mask substrate and an isolated pattern provided on the mask substrate, and a phase shifter is provided on each of the isolated patterns to give a phase difference to the phase of directly transmitted light from the mask substrate. In a phase difference mask for subjecting the isolated pattern to phase difference exposure on a photosensitive layer having a step using the phase shift light given the phase difference, the light transmitted through the isolated pattern is converted to the isolated pattern. The isolated pattern is provided so as to be separated from the adjacent isolated pattern by a distance that does not interfere with the light transmitted through the adjacent isolated pattern provided adjacent to the isolated pattern, and the relative phase difference between the isolated pattern and the light-shielding pattern is ( 90 ° ± 70 ° or (270 ° ± 70
°) and the first and second phase shifters are arranged on both sides of the light-shielding pattern in the order of the first and second phase shifters. The distance from the center to the outer edge is set short enough to cause interference between the phase-shifted light transmitted through the isolated pattern and the directly transmitted light of the mask substrate around the isolated pattern. Phase difference mask.