JPH03119355A - Mask and production thereof - Google Patents

Abstract

PURPOSE:To improve resolution and depth of focus by interfering the light transmitted through position shift parts in respective transmittable regions and the light transmitted through the parts not formed with the shift parts so as to weaken each other in the boundary parts of the transmittable regions and light shielding regions at the time of exposing. CONSTITUTION:Metallic layers 3 are patterned and formed to prescribed shapes on the main surface of a substrate 2. The metallic layers 3 serve as the light shielding regions A at the time of exposing. On the other hand, the transparent films 4a of the phase shift parts to shift the phase of the transmitted light are formed in a part of the transmittable regions B. A phase difference arises between the light transmitted through the transparent films 4a and the light transmitted through the regions having no transparent films 4a of the light transmitted through the respective transmittable regions B at the time of exposing and these light rays weaken each other in the boundary parts of the light shielding regions A and the transmittable regions B. The blur in the contour parts of the images projected onto a wafer is, therefore, decreased. The resolution and the depth of focus are improved in this way.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a mask used in photolithography and a manufacturing technique thereof, and particularly to a technique that is effective when applied to a mask used in the manufacturing of semiconductor integrated circuit devices. It is.

[Conventional technology]

2. Description of the Related Art In recent years, in semiconductor integrated circuit devices, the elements and wiring constituting the circuit have become finer, and the spacing between elements and wiring has become narrower.

However, with the miniaturization of elements and wiring, as well as the narrowing of element spacing and wiring spacing, a decrease in pattern transfer accuracy of a mask that transfers an integrated circuit pattern onto a wafer using coherent light is becoming a problem.

This will be explained below using FIGS. 24(a) to (6).

That is, when transferring the predetermined integrated circuit pattern formed on the mask 50 shown in FIG. The phase of the light transmitted through each Pa is the second
Since they are in phase as shown in Figure 4(b), these interference lights strengthen each other in the light shielding area N sandwiched between the pair of transmission areas PI and P2, as shown in Figure 24(C). Put it away. As a result, as shown in Figure 24 (6),
In addition to reducing the contrast of the projected image on the wafer,
The depth of focus becomes shallow, and the precision of pattern transfer of the mask is significantly reduced.

As a means to improve these problems, a phase shift phosphorography technique has been developed that improves the resolution and contrast of a projected image by manipulating the phase of light that passes through a mask. The phase shift phosphorography technique is described in, for example, Japanese Patent Publication No. 62-59296 and Japanese Patent Application Laid-Open No. 62-67514.

Japanese Patent Publication No. 62-59296 discloses that in a mask having a light-shielding region and a transmissive region, a transparent material is provided in at least one of the pair of transmissive regions sandwiching the light-shielding region, and the light is transmitted through each transmissive region during exposure. A mask structure is described in which a phase difference is created between the light beams, so that these light beams enter a region on the wafer that is originally a light-shielding region, interfere with each other, and weaken each other.

The effect of transmitted light on such a mask is shown in Figure 25 (a
) to (d) are as follows.

That is, when transferring the predetermined integrated circuit pattern formed on the mask 51 shown in FIG. Among Pi, the phase of the light transmitted through the transmission area P2 provided with the transparent material 52 and the phase of the light transmitted through the normal transmission area P are as follows in FIG.
As shown in (C), a phase difference of 180 degrees occurs. Therefore, the light transmitted through the pair of transmission regions PI, P2 is transmitted through the transmission regions P1. Because they interfere and cancel each other out in the light-shielding region N sandwiched between P2, the contrast of the projected image on the wafer is improved, the resolution and depth of focus are improved, and the pattern of the mask 51 is improved, as shown in Fig. 25 (d). Transfer accuracy is improved.

Furthermore, in the above-mentioned Japanese Patent Application Laid-Open No. 62-67514, in a mask including a light-shielding region formed by a light-shielding film and a transmissive region formed by removing the light-shielding film, a portion of the light-shielding film is removed. At the same time, a phase shift layer is provided on either the transparent region or the open pattern to create a phase difference between the light transmitted through the transmission region and the light transmitted through the open pattern. A mask structure is described in which the amplitude distribution of light transmitted through a transmission region is prevented from spreading in the lateral direction.

[Problem to be solved by the invention]

However, the present inventor found that the prior art described in Japanese Patent Publication No. 62-59296 has the following problems.

In other words, in the above-mentioned conventional technology that creates a phase difference between light transmitted through a pair of transmission regions, if the pattern is simply arranged repeatedly in one dimension, there is no problem with the arrangement of the transparent material. If the pattern is complex, such as an actual integrated circuit pattern, it may become impossible to arrange the transparent material, and there is a problem that sufficient resolution may not be obtained in some parts.

For example, when there is an integrated circuit pattern 53 as shown in FIG. 26, if a transparent material is provided in the transmission region P2, the resolution of the light-shielding regions N, . . . N2 will certainly be improved. However, in order to improve the resolution of the light-blocking area N, the transparent area P
If a transparent material is placed in the light-shielding region N2, the light transmitted through the transparent regions p, , p will be in phase, and the resolution of the light-shielding region N2 will be reduced. Furthermore, in order to improve the resolution of the light shielding area N, and to place a transparent material in a transmission pattern such as the transmission area P, it is sufficient to place the transparent material in a part of the transmission area P. Then, a phase inversion occurs in the light transmitted through the same transmission region P3, and an unnecessary pattern is formed on the wafer. Therefore, it becomes impossible to improve the resolution of the light shielding area N3.

Further, when the pattern is complex like an actual integrated circuit pattern, there are restrictions on the arrangement of the transparent material as described above, and therefore it is difficult to automatically create pattern data for the transparent material. Therefore, conventionally, when manufacturing a mask equipped with an optical phase shifting means, a pattern of transparent material had to be specially created while taking into account the above-mentioned arrangement constraints, and it took a lot of time and effort to manufacture the mask. There is a problem that requires

On the other hand, in the technique of Japanese Patent Laid-Open No. 62-67514, in which an open pattern is formed in a light-shielding area and a phase difference is created between the light transmitted through the open pattern and the light transmitted through the transmission area, as in the above-mentioned publication, When the pattern is complex and minute like an integrated circuit pattern, it becomes difficult to arrange the open pattern. For example, if the pattern width of the light-shielding area becomes narrower,
There is a problem that it becomes difficult to arrange the open pattern.

In addition, in this conventional technology, sufficient consideration is not given to the fact that the light intensity at the corners of the transmission area decreases as the transmission area becomes smaller, and the corners of the projected pattern image become rounded. There is a problem with it.

The present invention has been made in view of the above problems, and an object thereof is to provide a technique that can improve the transfer accuracy of a pattern formed on a mask.

Another object of the present invention is to provide a technique that can shorten the manufacturing time of a mask equipped with means for shifting the phase of light.

Another object of the present invention is to provide a technique that can improve the resolution not only of each side of a projected image but also of the corners.

The above and other objects and novel features of the present invention will become apparent from the description of the specification and the accompanying drawings.

[Means to solve the problem]

A brief overview of typical inventions disclosed in this application is as follows.

That is, the invention according to claim 1 provides a mask that includes a light-shielding region and a transmitting region and transfers a predetermined pattern by at least partially coherent light irradiation, the mask having a phase of the transmitted light on a part of the transmitting region. A phase shift portion is formed to shift, and a phase difference occurs between the light transmitted through the phase shift portion and the light transmitted through a transmission region where the phase shift portion is not formed, and the interference light of the light is In the mask, the phase shift portion is arranged so as to weaken each other at the boundary between the transmission region and the light shielding region.

The invention according to claims 5 and 9 is a mask manufacturing method in which pattern data of a phase shift portion is automatically created based on pattern data of a light-shielding region or a transparent region.

The invention according to claim 14 provides a mask that includes a light-shielding region and a transmission region on a mask substrate, and transfers a predetermined pattern by at least partially coherent light irradiation, wherein a part of the light-shielding region is provided with the mask substrate. A groove is formed that reaches the main surface of the groove, and a phase difference occurs between the light that has passed through the groove and the light that has passed through the transmission area, and the interference light of the light weakens each other at the end of the light-blocking area. like,
The mask has phase shift grooves formed in the mask substrate below the grooves.

The invention according to claim 18 provides a mask that includes a light-shielding region and a transmitting region on a mask substrate, and transfers a predetermined pattern by at least partially coherent light irradiation, wherein a part of the light-shielding region is provided with the mask substrate. A groove is formed that reaches the main surface of the light shielding area, and a phase difference occurs between the light that has passed through the groove and the light that has passed through the transmission area, so that the interference light of the light weakens each other at the end of the light blocking area. In this mask, a transparent film is provided above the groove, and sub-transmissive regions are formed at the corners of the transmissive region.

[Effect]

According to the above-mentioned invention according to claim 1, during exposure, in each transmission area, the light that has passed through the position shift part and the light that has passed through the part where this is not formed are divided into the transmission area and the light-blocking area. By destructively interfering with each other at the boundary, the blurring of the outline of the image projected onto the wafer is reduced, and the contrast of the projected image is greatly improved.
Resolution and depth of focus can be significantly improved.

In particular, in the case of the present invention, since a phase difference is generated within one transmission region, there are no restrictions on the arrangement of the phase shift portion even if the pattern on the mask is complex. Furthermore, even if the pattern width of the light-shielding region becomes narrower, the arrangement of the phase shift portion does not become difficult.

According to the inventions described in claims 5 and 9, there is no need to specially create pattern data for the transparent film or phase shift grooves, so that the manufacturing time of a mask equipped with an optical phase shift means can be significantly shortened. I can do it.

According to the invention described in claim 14, during exposure, the light that has passed through the transmission region and the light that has passed through the grooves and phase shift grooves formed in the light-shielding region weaken each other at the ends of the light-shielding region. By interfering in this manner, the blurring of the contour portion of the projected image is reduced, its contrast is greatly improved, and the resolution and depth of focus can be greatly improved.

According to the invention described in claim 18, by providing the sub-transmission area at the corner of the transmission area, the light intensity at the corner of the transmission area increases, so that not only the resolution of each side of the projected image but also the , it is also possible to improve the resolution at the corners.

[Example 1] FIG. 1 is a cross-sectional view of a main part of a mask which is an example of the present invention.
2(a) to 2(C) are cross-sectional views of essential parts of the mask showing the manufacturing process of this mask, FIG. 3(a) is a cross-sectional view showing the exposure state of the mask shown in FIG. 1, and FIG. (C) to (6) are explanatory diagrams showing the amplitude and intensity of light transmitted through the transmission region of this mask.

A mask 1a of the first embodiment shown in FIG. 1 is a reticle used, for example, in a predetermined manufacturing process of a semiconductor integrated circuit device. For example, an original image of an integrated circuit pattern five times the actual size is formed on the mask 1a of the first embodiment.

A transparent mask substrate (hereinafter simply referred to as substrate) 2 constituting the mask 1a is made of, for example, synthetic quartz glass with a refractive index of 1.47. For example, a thickness of 500 mm is provided on the main surface of the substrate 2.
~3000 metal layers 3 are patterned into a predetermined shape.

The metal layer 3 is made of, for example, a Cr film, and becomes a light-shielding region during exposure. Note that the metal layer 3 may have a laminated structure in which chromium oxide is laminated on top of a Cr layer.

Further, the portion where the metal layer 3 is removed becomes a transmissive region B upon exposure. The original image of the integrated circuit pattern formed on the mask la is composed of a light-shielding area A and a transparent area B.

In the mask la of Example 1, the metal layer 3 described above
A transparent film 4a patterned to have a width slightly wider than the pattern width is placed on the mask la with a part thereof protruding from the contour of the metal layer 3 beyond the transmission area. Therefore, one transmission area B is composed of an area covered with the transparent film 4a and an area not covered with the transparent film 4a.

The transparent film 4a is made of, for example, indium oxide (In).

). The material of the transparent film 4a has a transmittance equal to that of the substrate 2.
A material is selected that has a sufficiently high adhesion to the substrate 2 (necessarily at least 90%) and has high adhesion to the substrate 2. The width of the protruding portion of the transparent film 4a is, for example, about 0.5 μm, assuming that the pattern width of the transparent region B is about 2 μm. The transparent film 4a has a thickness of X from the main surface of the substrate 2.
I, the refractive index of the transparent film 4a is rz, and the wavelength of the light irradiated during exposure is λ, then X+=λ/ (2(n, -
1-1)]. This is because during exposure, a 180 degree phase difference is created between the light that has passed through the transparent film 4a and the light that has passed through the normal transmission area B, out of the light that has passed through one transmission area B. be.

For example, the wavelength λ of the light irradiated during exposure is 0.365.
um (i-line), when the transparent film 4a (7) refraction ¥-n is 1.5, the thickness of the transparent film 4a from the main surface of the substrate 2
, should be about 0.37 μm. Although not shown, alignment marks are formed on the mask 1a for alignment with the metal layer 3, for example, when forming the transparent film 4a.

Next, the method for manufacturing the mask 1a of Example 1 is shown in FIG.
) to (C).

First, after polishing and cleaning the surface of a transparent substrate 2 made of synthetic quartz glass or the like, as shown in FIG. A metal layer 3 is formed by a sputtering method or the like. Next, on the upper surface of this metal layer 3, for example, 0.4 to 0.8μ
7 photoresist (hereinafter referred to as resist) 5a is applied. Subsequently, after pre-baking the resist 5a, an electron beam E is applied to a predetermined portion of the resist 5a using an electron beam exposure method or the like based on integrated circuit pattern data of a semiconductor integrated circuit device that is encoded in advance on a magnetic tape (not shown) or the like. irradiate. On the right, the integrated circuit pattern data records the position coordinates, shape, etc. of the pattern.

Next, as shown in FIG. 2(b), for example, a resist 5 is applied.
After removing the exposed portion a with a predetermined developer, the exposed metal layer 3 is etched away by dry etching or the like to form a pattern in a predetermined shape.

Subsequently, the resist 5a is removed using a resist stripping solution,
After cleaning and inspecting the substrate 2, as shown in FIG. 2(C), a transparent film 4a made of indium oxide (InO) or the like is deposited on the main surface of the substrate 2 by sputtering or the like.

At this time, the thickness Xl of the transparent M4a from the main surface of the substrate 2
is, for example, about 0.37 μm.

After that, for example, 0.4 to 0°8μ is applied to the upper surface of the transparent film 4a.
A resist 5b having a thickness of m is applied, and an antistatic layer 6 made of aluminum (A72) having a thickness of 0.05 μm, for example, is formed on the upper surface by a sputtering method or the like.

Next, based on the pattern data of the transparent film 4a, the pattern of the transparent film 4a is transferred onto the resist 5b by an electron beam exposure method or the like.

The pattern data for the transparent film 4a is automatically created by enlarging or reducing the pattern width of the light shielding area A or the transmitting area B of the integrated circuit pattern data described above. For example, in the first embodiment, the pattern width of the light shielding area A is set to 0, for example.
．． By increasing the thickness by about 5 to 2.0 μm, pattern data for the transparent film 4a is automatically created.

After that, through steps such as development, etching of a predetermined portion of the transparent film 4a, removal of the resist 5b, and further cleaning and inspection,
A mask 1a shown in FIG. 1 is manufactured.

To transfer the integrated circuit pattern on the mask la onto a wafer coated with resist using the mask la manufactured in this manner, for example, the following procedure is performed.

That is, the mask la and the wafer are placed in a reduction projection exposure device (not shown), and the original image of the integrated circuit pattern on the mask la is optically reduced to 115 and projected onto the wafer, and the wafer is sequentially moved in a stepwise manner. By repeating projection exposure each time, the integrated circuit pattern on the mask la is transferred to the entire surface of the wafer.

Next, the operation of the first embodiment will be explained with reference to FIGS. 3(a) to 3(d).

In the mask 1a of Example 1 shown in FIG. 3(a), when an original image of a predetermined integrated circuit pattern formed on the mask 1a is transferred onto a wafer by a reduction projection exposure method or the like,
Across each transmission region of the mask 1a, a phase difference of 180 degrees occurs between the light transmitted through the transparent film 4a and the light transmitted through the normal transmission region B (Fig. 3(b), (C)). ).

Here, since the transparent film 4a is disposed around the transmission area B, the transmitted lights having opposite phases that have passed through the same transmission area B weaken each other at the boundary between the transmission area B and the light-blocking area A. Therefore, the blurring of the outline of the image projected onto the wafer is reduced, the contrast of the projected image is significantly improved, and the resolution and depth of focus are significantly improved (FIG. 3(d)).

Note that since the light intensity is the square of the light amplitude, the negative waveform of the light amplitude on the wafer is inverted to the positive side as shown in FIG. 3 (Company).

As described above, according to the first embodiment, it is possible to obtain the following effects.

(1),! When light is transmitted, a phase difference of 180 degrees occurs between the light transmitted through the transparent film 4a and the light transmitted through the region without the transparent film 4a among the light transmitted through each transmission region B, and these lights are By weakening each other at the boundary between the light shielding area and the transmission area B, it is possible to reduce blurring of the outline of the image projected onto the wafer. As a result, the contrast of the projected image can be significantly improved, and the resolution and depth of focus can be significantly improved.

(2) With (1) above, it is possible to widen the exposure margin.

(3) Since a phase difference is generated within one transmission region B, there is no restriction on the arrangement of the transparent film 4a even if the pattern on the mask la is complicated.

Further, even if the pattern width of the light shielding area A is narrow, it will not be difficult to arrange the transparent film 4a. As a result, even if the pattern formed on the mask la is complex and fine like an integrated circuit pattern, the pattern transfer accuracy does not deteriorate partially, and the pattern formed on the mask la can be easily formed on the mask la. It becomes possible to significantly improve the transfer accuracy of the entire pattern.

(4) By automatically creating the pattern data of the transparent film 4a based on the pattern data of the light shielding area A or the transmitting area B, the pattern data of the transparent film 4a can be created easily in a short time. This makes it possible to significantly shorten the manufacturing time of phase shift masks.

[Example 2] FIG. 4 is a cross-sectional view of a main part of a mask according to another embodiment of the present invention, FIG. 5(a) is a cross-sectional view showing the exposure state of the mask shown in FIG. 4, and FIG. ) to (a) are explanatory diagrams showing the amplitude and intensity of light transmitted through the transmission area of the mask shown in FIG. 4.

In the mask 1b of Example 2 shown in FIG. 4, the transparent film 4b is arranged near the center of the transmission area B.

In this case as well, by forming the transparent film 4b on the substrate 2 so that its thickness xl satisfies the relationship
As shown in Figures (a) to (6), in each transmission region B, B of the mask 1b, there is a 180 degree gap between the light transmitted through the transparent film 4b and the light transmitted through the normal transmission region B. A phase difference occurs (FIGS. 5(b) and 5(C)), and these lights pass through the transmission region B and the adjacent light-shielding region A.

By weakening each other at the boundary with A, it becomes possible to reduce blurring of the outline of the image projected onto the wafer. As a result, the contrast of the projected image can be significantly improved, and the resolution and depth of focus can be significantly improved (FIG. 5 (6)).

Further, in this case, the pattern data of the transparent film 4b may be automatically created by, for example, reversing the pattern data of the integrated circuit pattern from positive to negative and narrowing the pattern of the transparent region B by a predetermined width. .

Therefore, according to the second embodiment, it is possible to obtain the same effect as the first embodiment.

[Embodiment 3] Fig. 6 is a cross-sectional view of the main parts of a mask according to another embodiment of the present invention, Fig. 7 is a plan view of the main parts of the mask shown in Fig. 6, and Fig. 8 is a diagram showing the manufacture of this mask. 9(a) and 9(b) are cross-sectional views of the main parts of the mask showing the manufacturing process of this mask, and FIG. 10 shows the procedure for creating pattern data of phase shift grooves. FIG. 11(a) is a cross-sectional view showing the exposure state of the mask shown in FIG. FIG. 3 is an explanatory diagram showing the amplitude and intensity of light.

The mask of Example 3 will be explained below with reference to FIGS. 6 and 7. Note that the diagonal lines in FIG. 7 indicate the light-shielding areas.

In the mask lc of the third embodiment, a phase shift groove 7a is formed in the substrate 2 in place of the transparent film 4a of the first embodiment as a means for creating a phase difference in the light transmitted through the transmission region B during exposure. has been done.

The phase shift groove 7a is arranged around the transmission region B. That is, the phase shift groove 7a is arranged along the contour of the metal layer 3. For example, if the pattern width of the transmission region B is 2.0 μm, the width of the phase shift groove 7a is 0.
．． It is about 5 μm. Then, the depth of the phase shift groove 7a is d1, the refractive index of the substrate 2 is n2, and the wavelength of the light irradiated in the case of N light is λ, d=λ/ (2(n2-1>
) is formed to satisfy the relationship. This is because, during exposure, there is a 180 degree phase difference between the phase of the light that has passed through the phase shift groove 7a and the phase of the light that has passed through the normal transmission area B among the light that has passed through each transmission area B. This is to cause For example, if the wavelength λ of the light irradiated during exposure is set to 0
．． In the case of 365 μm (i-line), the phase shift groove 7
The depth d of a should be approximately 0°39 μm. Although not shown, the mask IC has, for example, a phase shift m1.
Alignment marks are formed for positioning with the metal layer 3 when forming a.

Next, a focused ion beam device Wt8 used for manufacturing this mask IC will be explained with reference to FIG.

Although not shown, a molten liquid metal such as gallium (Ga), etc., is housed inside the ion source 9 provided at the top of the main body of the apparatus. An extraction electrode 10 is installed below the ion source 9, and below it, a second lens electrode 11b and a first lens electrode 11b constituted by an electrostatic lens are provided.
An aperture electrode 12a is installed. Below the aperture electrode 12a, there is a second lens electrode 11b, a 27th aperture electrode 12b, a blanking electrode 13 for controlling ON/OFF of beam irradiation, and a third aperture electrode 1.
2c and a deflection electrode 14 are installed.

With such a configuration of each electrode, the ion beam emitted from the ion source 9 is controlled by the blanking electrode 13 and the deflection electrode 14, and is irradiated onto the mask IC held in the holder 15 before pattern formation. It looks like this. Then, when the ion beam scans,
For example, for each pixel unit of 0.02 x 0302 μm,
By setting the beam irradiation time and the number of scans in advance, the metal layer 3 or the substrate 2 can be etched.

The holder 15 is installed on a sample stage 16 that is movable in the X and Y directions, and the position of the sample stage 16 is recognized by a laser interference length measuring device 18 via a laser mirror 17 provided on the side. is performed, and the positioning is performed by a sample stage drive motor 9. In addition,
A secondary ion/secondary electron detector 2 is located above the holder 15.
0 is connected, and the generation of secondary ions and secondary electrons from the workpiece can be detected.

Further, an electron shower radiation section 21 is installed above the secondary ion/secondary electron detector 20 described above, so that charging of the workpiece can be prevented.

The inside of the processing system explained above is shown in the above-mentioned sample stage 1 in the figure.
The structure is such that a vacuum state is maintained by a vacuum pump 22 shown below 6. Further, the operation of each of the processing systems described above is controlled by each control section 23 to 27 provided outside the main body of the apparatus.
is further controlled by a control combination coater 33 via each interface section 28 to 32. The control computer 33 includes a terminal 34, a magnetic disk device 35 for recording data, and an MT deck 36.
It is equipped with

Next, a method for manufacturing the mask IC of Example 3 will be explained with reference to FIGS. 8, 9(a) and 9(b), and FIG. 10.

First, as shown in FIG. 9(a), a metal layer 3 of, for example, 500 to 3,000 layers is formed on the main surface of a polished and cleaned substrate 2 by sputtering, and then a mask IC is attached to a focused ion beam device 8. It is held in a holder 15.

Next, an ion beam is emitted from the ion source 9, and this ion beam is focused by each of the electrodes to a beam diameter of, for example, 0.5 μm. At this time, an ion beam current of 1.5μ8° is obtained. Then, this focused ion beam is irradiated onto a predetermined portion of the metal layer 3 based on the pattern data of the integrated circuit pattern recorded in advance on the magnetic tape of the MT deck 36, thereby etching the metal layer 3. On this occasion,
The irradiation time per vixel is, for example, 3
The number of beam scans per second is approximately 30 times. In this way, the metal layer 3 is patterned as shown in FIG. 90)). Note that the pattern formation of the metal layer 3 may be performed by electron beam exposure method or the like as in the first embodiment.

After that, a predetermined amount of ion beam is irradiated onto the alignment mark (not shown) formed on the mask IC, the generated secondary electrons are detected by the secondary ion/secondary electron detector 20, and alignment is performed based on the detected data. Calculate the position coordinates of the mark.

Then, based on the calculated position coordinates of the alignment mark, the sample stage 16 is moved so that the ion beam is irradiated to the position where the phase shift groove 7a is formed.

Next, based on the pattern data of the phase shift grooves 7a, the substrate 2 exposed by patterning the metal layer 3 is irradiated with an ion beam along the contour of the metal layer 3, and the phase shift grooves 7a are formed. a (Fig. 6) is formed. At this time, by using a focused ion beam, the depth, width, etc. of the phase shift groove 7a can be set easily and accurately.

The pattern data of the phase shift groove 7a is obtained by performing a logical operation on the pattern data of the light-shielding area A (or the transparent area B) and the pattern data obtained by enlarging or reducing the pattern of the shielding area A (or the transparent area B). Create by.

For example, as shown in FIG. 10, first, an LSI circuit design process (step 101a), a CAD design data process (step 10lb), and a Boolean OR process (IOIC) are performed.
After the integrated circuit pattern data is created by the above steps, in a sizing step (102), pattern data is created in which the pattern width of the light-shielding area A is increased by a predetermined dimension. At the same time, in a reverse tone step (103), the pattern data of the integrated circuit pattern is reversed from positive to negative to create pattern data of the transparent region B. Then, by performing a logical product (AND) of these pattern data (104), pattern data for the phase shift groove 7a is automatically created (105).

Next, after forming the phase shift groove 7a, the bottom surface of the phase shift groove 7a formed in the mask IC is covered with, for example, Freon (
Flattening is performed by dry etching using CF4) gas plasma. By flattening the bottom surface of the phase shift groove 7a in this manner, it becomes possible to improve the operability of the phase of light transmitted through this groove. In addition, during the dry etching process, a Freon gas is used, for example, Q
, is supplied at 29 sec/min into a plasma dry etching processing chamber whose pressure is reduced to 1 Torr.

In this way, the mask IC shown in FIGS. 6 and 7
is manufactured.

Next, the operation of the mask IC of Example 3 is shown in FIG. 11(a).
This will be explained by (6).

When transferring the original image of a predetermined integrated circuit pattern on the mask IC shown in FIG.
There is a phase difference of 180 degrees between the light that has passed through a and the light that has passed through normal transmission area B (Figure 11, etc.).
(C)).

Here, the transmitted light beams having mutually opposite phases transmitted through the same transmission region B are transmitted through the transmission region B on the mask IC.
Since it is placed around the transparent area B and the light shielding area A
They weaken each other at the boundary. Therefore, the blurring of the outline of the image projected onto the wafer is reduced, the contrast of the projected image is significantly improved, and the resolution and depth of focus are significantly improved (FIG. 11(d)). Note that since the light intensity is the square of the light amplitude, the negative waveform of the light amplitude on the wafer is inverted to the positive side as shown in FIG. 11(6).

As described above, according to the third embodiment, the following effects can be obtained.

(1) During exposure, a phase difference of 180 degrees occurs between the light transmitted through the phase shift groove 7a and the light transmitted through the normal transmission region B among the light transmitted through each transmission region B,
By making these lights weaken each other at the boundary between the light blocking area A and the transmitting area B, it is possible to reduce the blurring of the outline of the image projected onto the wafer.

As a result, the contrast of the projected image can be significantly improved, and the resolution and depth of focus can be significantly improved.

(2) With (1) above, it is possible to widen the exposure margin.

(3) Since a phase difference is generated within one transmission region B, there are no restrictions on the arrangement of the phase shift grooves 7a even if the pattern on the mask IC is complex.

In addition, even if the pattern width of the light-shielding area A is narrow, the phase shift)1
There is no difficulty in arranging 7a. As a result, even if the pattern formed on the mask IC is complex and fine, such as an integrated circuit pattern, the pattern transfer accuracy will not deteriorate partially and the pattern can be formed on the mask IC. It becomes possible to significantly improve the transfer accuracy of the entire pattern.

(4) By automatically creating the pattern data of the phase shift groove 7a based on the pattern data of the light shielding area A or the transmission area B, the pattern data of the phase shift groove 7a can be easily created, and the pattern data of the phase shift groove 7a can be easily created. It becomes possible to significantly shorten the creation time.

(5) By using the phase shift groove 7a instead of the transparent film in Example 1.2 as the optical phase shift means, a step of forming a transparent film is not required when manufacturing a mask IC.

(6)9 In addition to the above (4) and (5), when pattern data is applied to the metal layer 3 by a focused ion beam,
By also forming the phase shift groove 7a, the manufacturing process of the mask can be made easier than that of a mask using a transparent film as the optical phase shifting means, and the manufacturing time can be significantly shortened. becomes.

(Since it is possible to simplify the manufacturing process of the phase shift mask, appearance defects, foreign matter adhesion, scratches, etc. can be significantly reduced compared to masks that use a transparent film as the optical phase shift means. It becomes possible.

(8) In the case of a two-phase shift aTH, the film quality may deteriorate, the transmittance may deteriorate, or the adhesion to the substrate 2 may deteriorate due to the irradiation light or exposure light after the mask is manufactured, such as a transparent film for phase shift. There is no deterioration in the quality.

(9) According to (8) above, it is possible to improve the life of the mask compared to a mask using a transparent film as a light phase shifting means.

σQ, [8] above makes it possible to maintain the optical phase manipulation precision for a longer period of time than a mask using a transparent film as the optical phase shifting means.

In the case of 17a (1 phase shift), there is no need to consider deterioration of film quality, transmittance, or adhesiveness, as well as peeling of the film, which is the case when a transparent film is used as the optical phase shift means. It becomes possible to perform treatments such as ozone sulfuric acid cleaning and high-pressure water scrub cleaning at high temperatures.

Moreover, the above αD makes it possible to perform the foreign matter removal process better than a mask using a transparent film as a light phase shifting means.

[Embodiment 4] FIG. 12 is a cross-sectional view of a main part of a mask according to another embodiment of the present invention, FIG. 13(a) is a cross-sectional view showing the exposure state of the mask shown in FIG. 12, FIG. (b) to (d) are explanatory diagrams showing the amplitude and intensity of light transmitted through the transmission region of the mask shown in FIG. 12.

In the mask 1d of Example 4 shown in FIG. 12, the phase shift groove 7b is arranged near the center of the transmission region B.

In this case as well, the phase shift groove 7b is formed at a depth d
is formed on the substrate 2 so as to satisfy the relationship d=λ/(2(n, -1)), as shown in FIGS.
As shown in (6), each transparent region B of the mask 1d,
At B, a phase difference of 180 degrees occurs between the light transmitted through the phase shift groove 7b and the light transmitted through the normal transmission area B (Fig. 13(b), (C)), and these lights are transmitted. Area B
By weakening each other at the boundary between the light shielding areas A and the adjacent light shielding areas A, A, it becomes possible to reduce blurring of the outline of the image projected onto the wafer. As a result, the contrast of the projected image can be greatly improved, and the resolution and depth of focus can be greatly improved (
Figure 13 (6)).

Further, in this case, the pattern data of the phase shift groove 7b may be automatically created by, for example, narrowing the pattern of the transparent region B obtained by inverting the pattern data of the integrated circuit pattern by a predetermined width. good.

Therefore, according to the fourth embodiment, it is possible to obtain the same effect as the third embodiment.

[Embodiment 5] Fig. 14 is a sectional view of the main part of a mask according to still another embodiment of the present invention, Fig. 15 is a plan view of the main part of the mask shown in Fig. 14, and Fig. 16 is a cross-sectional view of the main part of the mask shown in Fig. 14. 17th plan view of essential parts of a mask for explaining an example of creating pattern data for a transparent region; FIG.
The figure is a flowchart showing the procedure for creating pattern data for the grooves and sub-transmission areas shown in Figure 16, and Figures 18(a) to (
i) is an explanatory diagram showing the pattern shape in the step of creating the groove and sub-transmission region pattern shown in FIG. 16;
9(a) is a cross-sectional view showing the exposure state of the mask shown in FIGS. 14 and 15, and FIGS. 19(5) and (6) are cross-sectional views showing the transparent area of the mask shown in FIGS. 14 and 15. FIG. 2 is an explanatory diagram showing the amplitude and intensity of light.

Below, the mask 1e of Example 5 is shown in FIGS. 14 and 15.
This will be explained using figures.

In the mask IC of Example 5, a plurality of grooves 37 are provided in the metal layer 3 constituting the light-shielding region A, reaching from the upper surface thereof to the main surface of the substrate 2.

As shown in FIG. 15, the groove 37 is a rectangular transmission area B.
, B are arranged in parallel along each side of the transmission region B so as to surround the region B. The width of the groove 37 is, for example, about 0.5 μm.

A transparent film 4C made of, for example, indium oxide (Ink) having a refractive index of 1.5 is provided above the groove 37.

The mask 1e has a structure in which a phase difference is generated between the light transmitted through the transparent film 4C and the groove 37 and the light transmitted through the transmission area B during exposure due to the transparent film 4C.

The thickness of the transparent film 4C from the main surface of the substrate 2 is X2, and as in Example 1, X=λ/ (2
(n, -1)). This means that, of the light irradiated onto the mask IC during exposure, there is a 180 degree phase difference between the phase of the light that has passed through the transparent film 4C and the groove 37 and the phase of the light that has passed through the transmission area B. This is to make it happen. For example, if the wavelength λ of the light irradiated during exposure is 0.365 μm (i-line),
The thickness X of the transparent film 4C from the main surface of the substrate 2 is 0.37
It may be about μm.

Furthermore, in the fifth embodiment, as shown in FIG. 15, for example, 0, 5 Xo,
A rectangular sub-transmission region C having a size of about 5 μm is provided. This is to prevent the four corners of the pattern formed on the wafer after development from becoming rounded instead of being at right angles, unlike the integrated circuit pattern on the mask le, as the integrated circuit pattern becomes finer. That is, by providing the sub-transmission regions C at the four corners of the integrated circuit pattern where the light intensity is most likely to decrease and the distortion becomes large, the projected image is corrected by increasing the light intensity near the four corners. Although not shown, alignment marks are formed on the mask IC for aligning the grooves 37 and the metal layer 3 when forming the grooves 37 and the transparent film 4C, for example.

To manufacture such a mask le, for example, the following procedure is performed.

That is, first, a metal layer 3 having a thickness of, for example, 500 to 3000 layers is formed on the main surface of the polished and cleaned substrate 2 by sputtering or the like, and then this is held in the focused ion beam device 8 described in Example 3 above. It is held in a container 15.

Next, based on the integrated circuit pattern data recorded in advance on the magnetic tape of the MT deck 36, the metal layer 3 on the main surface of the substrate 2 is patterned by a focused ion beam.

Thereafter, the metal layer 3 on the main surface of the substrate 2 is irradiated with a focused ion beam based on the pattern data of the groove 37 and the sub-transmission area C recorded in advance on the magnetic tape of the same <MT deck 36, and the metal layer 3 is A groove 37 is formed in 3.

The pattern data for the grooves 37 and the sub-transmission area C are automatically created by setting arrangement rules for the width of the rectangular transmission area, as will be described later.

Then, the pattern data of the transparent film 4C is created based on the pattern data of the integrated circuit pattern and the pattern data of the groove 37 and the sub-transmission area C, and based on this, the transparent film 4C is placed on the mask IC in accordance with the first embodiment. Form in the same manner.

Here, taking the integrated circuit pattern shown in FIG. 16 as an example, we will explain how to create pattern data for the groove 37 and the sub-transmission region C formed therein by following the flowchart in FIG. ) to (i). In addition,
In FIG. 16, the transparent film 4C is not shown in order to make the drawing easier to see. In addition, diagonal lines in FIGS. 18(a) to (i) indicate patterns created in each step.

First, data for the pattern 38 in the transparent region B is created as shown in FIG. 18(a) through the LSI circuit design process, CAD design data process, and Boolean OR process (
Steps 101a-101c).

Subsequently, in the step of sizing 1, as shown in FIG. 18(b), the pattern width of the transparent region B is set to 2.0
Create a pattern 39 with a thickness of about 6 μm (102 a)
.

At the same time, by the process of sizing 2, Fig. 18 (C))
As shown in , the pattern width of the transparent region B is set to 1.
Create a pattern 40 with a thickness of about 0 μm (102 b
).

Next, a corner clipping process is performed to obtain the shape shown in FIG. 18 (6).
), after creating the data of the pattern 41 by extracting only the corners of the pattern 39 (103a), the created data of the pattern 41 is reversed from positive to negative by a reverse tone process, and then the data of the pattern 41 is inverted from positive to negative by the reverse tone process, and then the data of the pattern 41 is created by extracting only the corners of the pattern 39 (103a). Pattern 4 shown in
2 data is created (104a).

On the other hand, the pattern 40 created in the sizing 2 process is inverted from positive to negative by a reverse tone process to create data for the pattern 43 shown in FIG. 18 (0) (103b).

By taking the AND of the data of the patterns 39, 42, and 43 shown in FIGS. 18(b), (e), and (f), the pattern 44 of the groove 37 is obtained as shown in FIG. 18(g). Create data (105 a, l O
6a).

On the other hand, by taking the AND of the data of pattern 40 shown in FIG. 18(C) and the data of pattern 41 shown in FIG. 18(d), the data of pattern 45 shown in FIG. (104b).

Next, it is determined whether the area of the created pattern 450 is smaller than 1/2 of the area a of the pattern 41 (
105 b). As a result, only the patterns whose area is smaller than 1/2 of the area a are selected, and data of the pattern 46 of the sub-transmission area C shown in FIG. 18(1) is created (10
6 b). The reason why the area of the pattern 45 is compared with a predetermined value is to add the sub-transmissive area C only to the convex corner of the pattern 38 of the transparent area B.

Next, the operation of the fifth embodiment will be explained with reference to FIGS. 19(a) to 19(d).

When the original image of a predetermined integrated circuit pattern on the mask IC shown in FIG.
A phase difference of 180 degrees occurs between the light that has passed through C and the groove 37 and the light that has passed through the transmission area B (see Fig. 19).
b), (C)).

Here, the light that has passed through the groove 37 on the right side of the transparent film 4C and the light that has passed through the transmission region B weaken each other at the end of the light-shielding region adjacent to the transmission region.

Therefore, the blurring of the outline of the image projected onto the wafer is reduced, the contrast of the projected image is significantly improved, and the resolution and depth of focus are significantly improved. Since the light intensity is the square of the light amplitude, the negative waveform of the light amplitude on the wafer is inverted to the positive side, as shown in FIG. 19 (6).

As described above, according to the fifth embodiment, it is possible to obtain the following effects.

(1), ! At the time of light, a phase difference of 180 degrees occurs between the light transmitted through the transparent film 4C and the groove 37 and the light transmitted through the transmission area B among the light irradiated onto the mask 1e.
By making these lights weaken each other at the end of the light-shielding area IA, it is possible to reduce the blurring of the outline of the image projected onto the wafer. As a result, the contrast of the projected image can be significantly improved, and the resolution and depth of focus can be significantly improved.

(2) With (1) above, it is possible to widen the exposure margin.

(3) With the above (1), it is possible to improve pattern transfer accuracy.

(4) By providing the sub-transmission areas C at the four corners of the transmission area B, the light intensity at the four corners of the projected image increases, making it possible to improve the resolution and further improving pattern transfer accuracy. becomes possible.

(5) By automatically creating the patterns of the grooves 37 and the transparent film 4C, it is possible to significantly shorten the manufacturing time of the phase shift mask compared to the conventional method.

[Embodiment 6] FIG. 20 is a cross-sectional view of the main part of a mask showing still another embodiment of the present invention, FIG. 21 is a plan view of the main part of this mask, and FIG.
FIG. 22(a) is a cross-sectional view showing the exposure state of the mask shown in FIGS. 20 and 21, and FIGS. 22(a) to (6) are explanatory views showing the amplitude and intensity of light transmitted through the transmission region.

Below, the mask 1f of Example 6 is shown in FIGS. 20 and 21.
This will be explained using figures.

In the mask 1f of Example 6, the grooves 3 are
The transparent film 4C of Example 5 is used as a means for creating a phase difference between the light transmitted through the transparent film 7 and the light transmitted through the transmission region B.
Instead, a phase shift groove 7C is formed in the substrate 2 below the groove 37.

Assuming that the depth of the phase shift groove 7C is d1, the refractive index of the substrate 2 is n2, and the wavelength of the N-directed light is λ, then d=λ/[2(n,-1>)] as in the third embodiment. It is formed to satisfy the relationship.

For example, when the wavelength λ of light is 0°365 μm (i-line), the depth d of the phase shift groove 7b may be about 0.39 μm.

The bottom surface of the phase shift groove 7C is substantially flattened by plasma dry etching treatment as in the third embodiment, in order to improve the operability of light transmitted therethrough. The phase shift groove 7C is formed, for example, by etching the substrate 2 by a depth d by increasing the number of scans of the focused ion beam when forming the groove 37.

Also, in the sixth embodiment, as in the fifth embodiment, 's
As shown in FIG. 21, rectangular sub-transmissive regions C of, for example, 0.5 Xo and 5 μm are provided at the four corners of the rectangular transparent region B. Although not shown, mask 1
For example, when forming the groove 37 and the sub-transmission region C,
Alignment marks are formed to align them with the metal layer 3.

The pattern data for the groove 37 and the sub-transmissive region C are created in the same manner as in Example 5, for example.

Further, in this case, the pattern data of the phase shift groove 7C is the same as the pattern data of the groove 37.

Next, the operation of the sixth embodiment will be explained with reference to FIGS. 22(a) to 22(d).

When the original image of a predetermined integrated circuit pattern on the mask lf shown in FIG. A phase difference of 180 degrees occurs between the light and the light (FIGS. 13(b) and (C)).

Here, out of the light irradiated onto the mask 1f, the light that has passed through the groove 37 and the phase shift groove 7C and the light that has passed through the transmission area B are transmitted to the edges of the light-shielding areas A and A adjacent to the width of the transmission area. They weaken each other. Therefore, the blurring of the outline of the image projected onto the wafer is reduced, the contrast of the projected image is greatly improved, and the resolution and depth of focus are significantly improved (FIG. 22). Note that since the light intensity is the square of the light amplitude, the negative waveform of the light amplitude on the wafer is inverted to the positive side as shown in FIG. 22(d).

As mentioned above, in the present Example 6, (1) to
In addition to the effect (5), the following effects can be obtained.

(1) By using the phase shift grooves 7c instead of the transparent film 4C as the optical phase shift means, a step of forming a transparent film for phase shift is not required when manufacturing the mask 1f.

2) In addition to the above (1), when the groove 37 is formed in the metal layer 3 by a focused ion beam, the phase shift groove 7C is also formed, so that the mask 1e of Example 5 is
The manufacturing process of the phase shift mask can be made easier, and the manufacturing time can be significantly shortened.

(3) Since it becomes possible to simplify the manufacturing process of the 1-phase shift mask, appearance defects, adhesion of foreign matter, scratches, etc. can be significantly reduced compared to the mask le of Example 5.

(4) In the case of 6 phase shift and groove 7C, the film quality may deteriorate, the transmittance may deteriorate, or the substrate 2 There will be no deterioration in adhesion with the

(5) According to (4) above, it is possible to improve the service life compared to a mask using a transparent film as a light phase shifting means.

(6) According to (4) above, it becomes possible to maintain the optical phase manipulation accuracy for a longer period of time than in a mask using a transparent film as the optical phase shifting means.

(7) In the case of the 0 phase shift groove 7C, there is no need to consider deterioration of film quality, transmittance, or adhesiveness, as well as peeling of the film, which is the case when a transparent film is used as the optical phase shift means. 1f can be subjected to treatments such as ozone sulfuric acid cleaning at high temperatures and high-pressure water scrub cleaning.

(8) According to (7) above, it becomes possible to perform the foreign matter removal process better than a mask using a transparent film as a light phase shift means.

[Embodiment 7] FIG. 23 is a sectional view of a main part of a mask showing still another embodiment of the present invention.

In the mask 1g of Example 7 shown in FIG. 23, a phase shift groove 7d is formed in at least one of the pair of transparent regions B, which sandwich the light-shielding region A.

The bottom surface of the phase shift groove 7d is substantially flattened by plasma dry etching treatment as in the third embodiment, in order to improve the operability of the phase of the light transmitted therethrough.

This embodiment 7 has the meaning of shifting the phase of light, and
This is similar to the conventional technique of providing a transparent film on one of a pair of transmissive regions, and can be applied to areas where an integrated circuit pattern is simply arranged, such as a memory cell, for example.

For example, the phase shift groove 7d is formed by etching the substrate 2 by a depth d by increasing the number of beam scans when etching the metal layer 3 with a focused ion beam to form the transmission region B, as in the sixth embodiment. Form.

As described above, according to the seventh embodiment, it is possible to obtain the following effects.

(1), i! In the case of light, the opening of the light transmitted through each of the transmission regions B of a pair of transmission regions E and B sandwiching the light-shielding region A is 18.
By creating a phase difference of 0 degrees, the light transmitted through each of the transmission regions B that sandwich the light-shielding region A weakens each other in the light-shielding region, so that the image of the light-shielding region A sandwiched between the pair of transmission regions It becomes possible to improve the resolution of the pattern and improve the pattern transfer accuracy.

(2) By using the phase shift groove 7d instead of the conventional transparent film as the optical phase shift means, there is no need for a step of forming a transparent film when manufacturing the mask Ig.

(3) In addition to the above (2), when patterning the metal layer 3 with a focused ion beam, the phase shift groove 7d
By forming the phase shift mask at the same time, the manufacturing process of the phase shift mask can be made easier than in the past, and the manufacturing time can be significantly shortened.

(4) Since it becomes possible to simplify the manufacturing process of the 1-phase shift mask, appearance defects, adhesion of foreign substances, scratches, etc. can be significantly reduced compared to the conventional method.

(5) In the case of one phase shift groove 7d, the film quality, transmittance, or adhesiveness, for example, does not deteriorate due to irradiation light or exposure light after mask manufacturing, unlike conventional transparent films for phase shift.

(6) According to (5) above, it becomes possible to improve the life of a mask equipped with an optical phase shifter compared to the conventional one.

(7) With (5) above, the optical phase manipulation precision can be maintained for a longer period of time than conventionally.

(8) The six phase shift grooves 7d do not require consideration of deterioration in film quality, transmittance, or adhesiveness, as well as peeling of the film, as with a transparent film for phase shifting, so it is possible to use the six phase shift grooves 7d at high temperatures for 1 g of mask. It becomes possible to perform treatments such as ozone sulfuric acid cleaning and high-pressure water scrub cleaning.

(9) According to (8) above, it is possible to remove foreign substances better than with a mask using a transparent film.

As above, the invention made by the present inventor has been specifically explained based on Examples, but it should be noted that the present invention is not limited to the Examples and can be modified in various ways without departing from the gist thereof. Not even.

For example, in the third embodiment, the case was explained in which the pattern data of the phase shift groove was created by taking the logical product of the pattern data created by enlarging the pattern of the light-blocking area and the pattern data of the transparent area. The pattern is not limited to this, and various changes are possible. For example, the pattern may be created by enlarging the pattern of the light-shielding region and then calculating the difference between the pattern of the original light-shielding region.

Moreover, the above-mentioned Example 1. 2. Although the case where the transparent film is made of indium oxide has been described in No. 5, the transparent film is not limited thereto, and may be made of silicon dioxide, silicon nitride, magnesium fluoride, polymethyl methacrylate, or the like.

The above explanation has mainly been about the application of the invention made by the present inventor to masks used in the manufacturing process of semiconductor integrated circuit devices, which is the field of application behind the invention, but the invention is not limited to this and can be applied to a variety of other applications. This method can be applied to technical fields that require transferring a predetermined pattern onto a predetermined substrate using photolithography technology.

〔Effect of the invention〕

Among the inventions disclosed in this application, the effects obtained by typical inventions are briefly described below.

That is, according to the invention as set forth in claim 1, during exposure, in each transmission area, the light that has passed through the transparent film or the phase shift groove and the light that has passed through the part where these are not formed are transmitted through the transmission area. By destructively interfering with each other at the boundary between the wafer and the light shielding area, the blurring of the outline of the image projected onto the wafer is reduced, the contrast of the projected image is greatly improved, and the resolution and depth of focus are significantly increased. can be improved. Particularly in this case, since a phase difference is generated in the light transmitted through one transmission region, there are no restrictions on the arrangement of the transparent film even if the pattern on the mask is complex. Further, even if the pattern width of the light-shielding region is narrow, it does not become difficult to arrange the transparent film. As a result, even if the pattern on the mask is complex and minute, such as an integrated circuit pattern, the pattern transfer accuracy will not deteriorate locally, and the transfer accuracy of the entire pattern formed on the mask will be improved. It is possible to significantly improve the performance.

According to the invention described in claim 5 or 9, it is not necessary to specially create pattern data for the transparent film or the phase shift groove, so that the manufacturing time of a mask equipped with an optical phase shift means can be significantly shortened. .

According to the fourteenth aspect of the invention, during exposure, the light transmitted through the transmission region and the light transmitted through the grooves and phase shift grooves formed in the light-shielding region weaken each other at the ends of the light-shielding region. By interfering, the blurring of the outline of the image projected onto the wafer is reduced, the contrast of the projected image is significantly improved, and the resolution and depth of focus can be significantly improved. As a result, it becomes possible to improve pattern transfer accuracy.

According to the invention described in claim 18, the light intensity at the corner of the transmission area is increased by the sub-transmission area provided at the corner of the transmission area, so that not only the resolution of each side of the projected image but also the resolution of the projected image is increased. It is also possible to improve the resolution of corners.

[Brief explanation of drawings]

FIG. 1 is a sectional view of the main part of a mask that is an embodiment of the present invention, FIGS. 2(a) to (C) are sectional views of the main part of the mask showing the manufacturing process of this mask, and FIG. 3(a) 1 is a cross-sectional view showing the exposure state of the mask shown in FIG. 1, FIG. 5(a) is a sectional view showing the exposure state of the mask shown in FIG. 4; FIG. 5(a) is a cross-sectional view of the mask shown in FIG. An explanatory diagram showing the amplitude and intensity of light transmitted through a transmission region, FIG. 6 is a sectional view of a main part of a mask according to another embodiment of the present invention, and FIG. 7 is a plane view of a main part of the mask shown in FIG. 6. 8 is a configuration diagram of a focused ion beam device used for manufacturing this mask, 91ffl(a), υ is a sectional view of the main part of the mask showing the manufacturing process of this mask, and FIG. 10 is a phase shift groove 11(a) is a cross-sectional view showing the exposure state of the mask shown in FIG. 6, and FIGS. Explanatory diagram showing the amplitude and intensity of light transmitted through the transmission area of the mask, 1st
2 is a cross-sectional view of a main part of a mask according to another embodiment of the present invention, FIG. 13(a) is a cross-sectional view showing the exposure state of the mask shown in FIG. 12, and FIGS. 13(b) to (6) ) is an explanatory diagram showing the amplitude and intensity of light transmitted through the transmission region of the mask shown in FIG. 12, FIG. 14 is a sectional view of a main part of a mask according to still another embodiment of the present invention, and FIG. 15 is a plan view of the main part of the mask shown in Fig. 14, Fig. 16 is a plan view of the main part of the mask for explaining an example of creating pattern data for grooves and sub-transmission regions, and Fig. 17 is a plan view of the main part of the mask shown in Fig. 16. 18(a) to (i) are explanatory diagrams showing pattern shapes in the process of creating patterns for the grooves and sub-transmissive regions shown in FIG. 16. , FIG. 19(a) is a cross-sectional view showing the exposure state of the mask shown in FIG. 14 and FIG. 15, and FIG. 19(b) to (6) are the transparent areas of the mask shown in FIG. 14 and FIG. FIG. 20 is a sectional view of a main part of a mask showing still another embodiment of the present invention; FIG. 21 is a plan view of a main part of this mask; a) is a cross-sectional view showing the exposure state of the mask in FIGS. 20 and 21; FIGS. 22(b) to (6) are explanatory diagrams showing the amplitude and intensity of light transmitted through the transmission area; FIG. 24(a) is a sectional view of the main part of a mask showing still another embodiment of the present invention; FIG. 24(a) is a sectional view showing the exposure state of a conventional mask; FIGS. Explanatory diagram showing the amplitude and intensity of light transmitted through the transmission region, Fig. 25 (a
) is a cross-sectional view showing the exposure state of a conventional mask, Figures 25 and 25 are explanatory diagrams showing the amplitude and intensity of light transmitted through the transmission area of a conventional mask, and Figure 26 shows a conventional mask. FIG. 1a to 1g...mask, 2...mask substrate, 3...
- Metal layer, 4a to 4C...transparent film, 5a. 5b...Resist, 6...Antistatic layer, 7a to 7d
... phase shift groove, 8 ... focused ion beam device,
9... Ion source, 10... Extraction electrode, lla,
llb...first and second lens electrodes, 12a to 12C.
...First to third aperture electrodes, 13...Blanking electrode, 14... Deflection electrode, 15... Holder, 16
...Sample stage, 17...Laser mirror 18...
Laser interference length measurement device, 19... Sample stage drive morph, 2
0... Secondary ion/secondary electron detector, 21... Electron shower radiation section, 22... Vacuum pump, 23-27.
...Control section, 28-32...Interface section, 3
3... Control computer, 34... Terminal, 3
5... Magnetic disk device, 36... MT deck, 3
7... Groove, 38-46... Pattern, A... Light blocking area, B... Transmissive area, C... Sub-transmissive area, E...
...Electron beam, 50.51...Conventional mask, 52...
・Transparent material, 53...Integrated circuit pattern, P-P s
...Transmission area of conventional mask, N'=
Ns: Light-shielding area in a conventional mask.

Claims (1)

[Claims] 1. A mask that includes a light-blocking area and a transmitting area and transfers a predetermined pattern by at least partially coherent light irradiation, the mask shifting the phase of transmitted light to a part of the transparent area. A phase shift portion is formed, and a phase difference occurs between the light transmitted through the phase shift portion and the light transmitted through the transmission region where the phase shift portion is not formed, and the interference light of the light is A mask characterized in that the phase shift portion is arranged so as to weaken each other at a boundary between the region and the light-shielding region. 2. Claim 1, wherein the phase shift portion is a transparent film, and the transparent film is disposed around the transmission area.
Mask as described. 3. Claim 1, wherein the phase shift portion is a transparent film, and the transparent film is disposed at the center of the transmission area.
Mask as described. 4. If the thickness of the transparent film from the main surface of the mask substrate is X, the refractive index of the transparent film is n_1, and the wavelength of the irradiated light is λ, then the thickness X of the transparent film is X=λ /[2(n_1
-1)] The mask according to claim 2 or 3, wherein the mask satisfies the following relationship. 5. When manufacturing the mask according to claim 2 or 3, the pattern data of the transparent film is automatically created by enlarging or reducing the pattern of the light shielding area or the transmitting area. Production method. 6. The mask according to claim 1, wherein the phase shift portion is a phase shift groove formed on a mask substrate, and the phase shift groove is arranged around the transmission region. 7. The mask according to claim 1, wherein the phase shift portion is a phase shift groove formed on a mask substrate, and the phase shift groove is disposed at the center of the transmission region. 8. If the depth of the phase shift groove is d, the refractive index of the mask substrate is n_2, and the wavelength of the irradiated light is λ, then the depth d of the phase shift groove is d=λ/[2(n_2− 10. The mask according to claim 6 or 7, wherein the mask satisfies the following relationship: 1). 9. When manufacturing the mask according to claim 6 or 7, the pattern data of the phase shift groove is enlarged or reduced by the pattern data of the light-shielding region or the transmissive region and the pattern of the light-shielding region or the transmissive region. A method for manufacturing a mask, characterized in that the mask is automatically created by performing logical operations on obtained pattern data. 10. When manufacturing the mask according to claim 6, the pattern data of the phase shift groove is automatically generated by ANDing the pattern data of the transparent region and the pattern data obtained by enlarging the pattern of the light-blocking region. A method for manufacturing a mask, characterized in that it is created by: 11. A method of manufacturing a mask, characterized in that when manufacturing the mask according to claim 7, pattern data of the phase shift groove is automatically created by reducing pattern data of the transmission region. 12. A method for manufacturing a mask, characterized in that when manufacturing the mask according to claim 6 or 7, the transmission region and the phase shift groove are simultaneously formed by a focused ion beam. 13. When manufacturing the mask according to claim 6 or 7, after forming the phase shift groove on a mask substrate, the bottom surface of the phase shift groove is flattened by dry etching treatment. . 14. A mask comprising a light-shielding region and a transmitting region on a mask substrate and transferring a predetermined pattern by at least partially coherent light irradiation, wherein a groove reaching a main surface of the mask substrate is formed in a part of the light-shielding region. At the same time, a phase difference occurs between the light that has passed through the groove and the light that has passed through the transmission area, and the interference light of the light weakens each other at the end of the light-blocking area. A mask characterized in that a phase shift groove is formed in a lower mask substrate. 15. If the depth of the phase shift groove is d, the refractive index of the mask substrate is n_2, and the wavelength of the irradiated light is λ, then the depth d of the phase shift groove is d=λ/[2(n_2− 1)]
15. The mask according to claim 14, wherein the mask satisfies the following relationship. 16. A method for manufacturing a mask, characterized in that when manufacturing the mask according to claim 14, the grooves and the phase shift grooves are simultaneously formed by a focused ion beam. 17. A method of manufacturing a mask according to claim 14, wherein after forming the phase shift groove on a mask substrate, the bottom surface of the phase shift groove is flattened by dry etching. 18. A mask comprising a light-shielding region and a transmitting region on a mask substrate and transferring a predetermined pattern by at least partially coherent light irradiation, wherein a groove reaching a main surface of the mask substrate is formed in a part of the light-shielding region. is formed above the groove so that a phase difference occurs between the light that has passed through the groove and the light that has passed through the transmission area, and interference light of the light weakens each other at the end of the light-blocking area. 1. A mask comprising: a transparent film; and a sub-transmissive region formed at a corner of the transmissive region. 19. A mask comprising a pair of transmitting regions sandwiching a light-shielding region on a mask substrate, and transferring a predetermined pattern by at least partially coherent light irradiation, the mask comprising a pair of transmitting regions sandwiching a light-shielding region therebetween, and in which a predetermined pattern is transferred to one of the pair of transmitting regions. A mask characterized by forming phase shift grooves that cause a phase difference between light transmitted through the region. 20. If the depth of the phase shift groove is d, the refractive index of the mask substrate is n_2, and the wavelength of the irradiated light is λ, then the depth d of the phase shift groove is d=λ/[2(n_2− 1)]
20. The mask according to claim 19, wherein the mask satisfies the following relationship. 21. A method for manufacturing a mask, characterized in that when manufacturing the mask according to claim 19, the transmission region and the phase shift groove are simultaneously formed by a focused ion beam.