JPH0422954A - Mask and exposing device and method using mask - Google Patents

Abstract

PURPOSE:To improve the transfer accuracy of a complicated and fine pattern formed on a mask by irradiating 1st and 2nd patterns on the mask with two light beams which have phase difference respectively and are at least partially coherent. CONSTITUTION:The 1st and the 2nd patterns 9a and 9b on the mask 9 where the 1st and the 2nd patterns 9a and 9b are constituted are irradiated with the two light beams 1 which have the phase difference respectively and are at least partially coherent so that light beams transmitted through the transmissive areas of the 1st and the 2nd patterns 9a and 9b may interfere and weaken each other at the boundary part where the accuracy of a desired pattern is required. Then, the transmission patterns of the light beams are composited to generate the desired pattern on a sample 15 to be irradiated. Thus, the transfer accuracy of the boundary part where the accuracy of the desired pattern is required is improved.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a mask, an exposure apparatus using a mask, and an exposure method using a mask, and in particular, a technique effective for wafer exposure used in the manufacture of semiconductor integrated circuit devices. It is related to.

[Background Art] In recent years, in semiconductor integrated circuit devices, the elements and wiring constituting the circuit have been miniaturized, and the spacing between elements and wiring has been reduced.

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. 10(a) to 10(d).

That is, when a predetermined integrated circuit pattern formed on the mask 100 shown in FIG. The phase of the light transmitted through each of ,, P, is
Since they are in phase as shown in FIG. 10(b), these interference lights are transmitted in the light-shielding region N sandwiched between the above-mentioned pair of transmission regions P, P, as shown in FIG. 10(C). They strengthen each other. As a result, as shown in FIG. 10(d), the contrast of the projected image on the wafer decreases, and the depth of focus becomes shallow, resulting in a significant decrease in pattern transfer accuracy of the mask.

As a means to improve these problems, a phase shift lithography technique has been developed that improves the resolution and contrast of a projected image by manipulating the phase of light passing through a mask. The phase shift lithography 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 transmitting region, a transparent material is provided to create a phase difference in at least one of a pair of transmitting regions sandwiching the light-shielding region, and each A mask structure is described in which a phase difference is created between the light that has passed through the transmission area of the wafer, so that these lights interfere and weaken each other in an area on the wafer that is originally a light-blocking area.

The effect of transmitted light on such a mask is shown in Figure 11 (a
) to (d) are as follows.

That is, when a predetermined integrated circuit pattern formed on the mask 101 shown in FIG. ,,P, there is a difference between the phase of the light that has passed through the transmission area P1 provided with the transparent material 102 and the phase of the light that has passed through the normal transmission area P3.
) and (c), a phase difference of 180 degrees occurs. Therefore, in the light-shielding area N sandwiched between these transparent areas P, , P, they interfere and cancel each other out, so as shown in FIG.
As shown in d), the depth of focus on the wafer is improved and the pattern transfer accuracy of the mask 101 is improved.

[Problems to be Solved by the Invention] However, the present inventors have found that the prior art described in the above-mentioned Japanese Patent Publication No. 62-59296 and others has the following problems.

That is, in the above-mentioned conventional technique in which a transparent material is arranged on a substrate in order to generate a phase difference between the light transmitted through a pair of transmission regions, when the pattern is not simply arranged repeatedly in one dimension, , problems arise in the placement of transparent materials. In particular, when the pattern is as complex as an actual integrated circuit pattern, not only is there a constraint on the pattern design, but the transparent material placed on the substrate can be There was a problem in that it was very difficult to inspect whether there were any chips or remaining appearance defects.

Further, according to the above-mentioned conventional method, there is a problem in that it takes a lot of time to manufacture a mask provided with a transparent material in the case of a complex pattern such as an integrated circuit pattern.

The present invention has been made in view of the above-mentioned problems, and its purpose is to provide a technique that can improve the transfer accuracy of a complex and fine pattern formed on a mask.

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

[Means for Solving the Problems] Representative inventions disclosed in this application will be summarized as follows.

The invention according to claim 1 has a first pattern and a second pattern each having a light-blocking area and a transmitting area, and
A mask for creating a desired pattern on an irradiated sample by irradiating two types of patterns with at least partially coherent light having a phase difference and synthesizing the transmitted patterns of the light, the mask comprising: At the boundary where accuracy of the desired pattern is required, the first
The light transmitted through the transmission area of the pattern and the light transmitted through the transmission area of the second pattern interfere and weaken each other.
The first pattern and the second pattern are formed on the same substrate, or the first pattern and the second pattern are formed separately on two substrates.

In the exposure apparatus according to the second aspect of the invention, there is provided a light source that generates an at least partially coherent light beam, a light beam splitting means for splitting the coherent light beam into two, and a light beam that is recombined from the light beam splitting means. an optical phase shift member placed on either side of the optical path until the first pattern and the second pattern pass through the first pattern, an optical system that combines the light beams transmitted through the first pattern and the second pattern into a single light beam; an optical system that reduces and projects onto the irradiated sample, and the optical phase shift member shifts the phase of the light that passes through the first pattern and the light that passes through the second pattern by 180 degrees, and The desired pattern synthesized above was created.

In the exposure method according to claim 3, the first pattern and the second pattern on the mask according to claim 1 each have at least partially coherent two patterns having a phase difference.
Two lights were irradiated and the transmission patterns of those lights were combined to create a desired pattern on the irradiated sample.

Note that in this specification, an at least partially coherent light beam refers to a light beam that has sufficient coherence to achieve an interference and destructive effect.

Furthermore, in this specification, the term "boundary section" includes not only the boundary between line segments forming the desired pattern, but also a region sandwiched between two line segments.

[Operation] According to the above-described means, the light transmitted through the transmission area of the first pattern and the light transmitted through the transmission area of the second pattern interfere with each other at the boundary where precision of the desired pattern is required. irradiating the first pattern and the second pattern on the mask forming the first pattern and the second pattern with two at least partially coherent lights each having a phase difference so as to weaken each other; However, since the desired pattern is created on the irradiated sample by combining these light transmission patterns, it is possible to improve the transfer accuracy of the boundary portion where the accuracy of the desired pattern is required.

[Example 1] Fig. 1 is a block diagram of main parts of an exposure optical system which is an embodiment of an exposure apparatus using a mask of the present invention, and Figs. The principal part plan views of the mask of the invention, FIGS. 5 to 7, correspond to the previous figures, FIGS. 2 to 4, respectively, and are explanatory diagrams showing the amplitude and intensity of light passing through the mask.

The exposure apparatus of this embodiment is functionally divided roughly into four elements. The first is an element that irradiates the mask 9 with two light beams with a phase difference (the first element), and the second is the element that consists of the mask 9 (the second element).
, the third synthesizes the two transmitted lights of the mask 9 and generates the irradiated sample 1.
Element that is reduced to 5 and irradiated (third element)
, the fourth is the synthesis of a single luminous flux all! ! This is an element (fourth element) consisting of an alignment mechanism.

The first element consists of a light source 1 that emits partially coherent light, an expander 2 that spreads the light emitted from the light source 1, a mirror 3°6 that bends the optical path, and a mirror that transmits some of the incident light and transmits some of the light. It is composed of a reflecting half mirror 4 and a phase shift member 5 that changes the phase of light. Further, the third element includes lenses 10 and 11, a mirror 12, and a half mirror for converting the two transmitted lights from the mask 9 into parallel lights.
13, a reduction lens X4 for reducing light, a sample to be irradiated 15, and a movable sample stage 16. The fourth element is mirror 3. Half mirror 4, lens 10. and an alignment mechanism 7 for moving the mirror 12, and its control circuit 8).

In the above, the mirror 3 is provided to make the entire device smaller, but the light from the expander 2 may be directly input without providing the mirror 3. Half mirror 4 has the function of splitting the light from expander 2 into two.
It is placed on the first pattern 9a on the mask 9. The phase shift member 5 is placed between the half mirror 4 and the mirror 6 or between the mirror 12 and the half mirror 13 (not shown), and has the function of shifting the phase by a predetermined amount. For the phase shift member 5, synthetic quartz glass having a refractive index of 1.47 is used, for example. If the phase difference between the first light beam 30 from the mirror 12 and the second light beam 31 from the lens 11 is O when the mask 9 is arranged and the phase shift member 5 is not provided, then the phase shift member The thickness d is determined by d=mλ/2(n-1) (m: integer), where λ is the wavelength of the light source and n is the refractive index of the member.

The reason for using the phase shift member 5 is that during exposure, there is a gap of 180 degrees between the light that has passed through the phase shift member 5 and the light that has not passed through the phase shift member 5, out of the light that has passed through the two transmission areas. This is to generate a phase difference of degrees. For example, the wavelength λ of the light irradiated during exposure is 0.365 μm (i-line)
, when the refractive index n of the phase shift member 5 is 1.5, the thickness X of the phase shift member 5 is m of 0.365 μm.
(Integer) Just double it.

The mirror 6 is a mirror for making the light transmitted through the half mirror 4 and the light transmitted through the phase shift member 5 parallel. Note that the two patterns 9a and 9b on the mask 9 are arranged so as to be perpendicular to the two lights 30 and 31.

Lenses 10.11 are normally arranged so that the centers of their front axes coincide with the centers of patterns 9a and 9b, respectively.

The half mirror 13 is for combining two lights 30° 31. The mirror 12 has a function of bending the light 30 in order to combine the lights.

The alignment mechanism 7 related to the fourth element is a mechanism for moving a part of the optical system necessary for alignment among the optical systems of the exposure apparatus, and uses a piezoelectric element or the like. In Figure 1, mirror 3° half mirror 4, lens 1
0. Although it is configured to move the mirror 12,
Naturally, the type and number of optical elements to be moved vary depending on the configuration of the exposure apparatus. Note that a method for controlling the movement of this alignment mechanism 7 will be described later.

Next, the structure of the mask 9 of the present invention, which is the second element, will be explained.

First, it is assumed that the pattern (desired pattern) to be formed on the irradiated sample 15 is an inverted-shaped pattern 29 having a two-dimensional spread as shown in FIG. 2(C). Figure 2 (a
) and (b) are plan views of examples of the first pattern 9a and the second pattern 9b, respectively, which are formed on the mask 9 to create such a desired pattern.
The desired pattern (C) synthesized in step 5 is considered and the relative positional relationship is maintained.

Both the first pattern 9a and the second pattern 9b are
A pattern is created from a combination of a light-blocking area and a transparent area, respectively. These patterns may be formed on one substrate, or may be formed separately on two glass substrates. However, in this case, the difference in the thickness of the glass substrate is also corrected by the thickness of the phase shift member. In FIG. 2, the transparent area is shown by a white surface, and the light-blocking area is shown by diagonal lines.

The transmission pattern 32 in FIG. 2(a) has an inverted-shaped transmission region, and the transmission pattern 36 in FIG. 2(b) has a slightly smaller inverted-shaped shielding within the inverted-shaped transmission region. Area 3
4, and is configured to have a band-shaped transmission area 36.

Next, the operation of the present invention will be explained.

Light emitted from an at least partially coherent light source 1 is expanded by an expander 2, bent by a mirror 3, and then sent to an optical system of one of the two beams divided by a half mirror 4. A phase shift member 5 is arranged in the optical path. The light transmitted through the phase shift member 5 is given a phase difference of 180 degrees, and then is irradiated onto the second pattern 9b of the mask 9 by the mirror 6. On the other hand, the light transmitted through the half mirror 4 is irradiated onto the first pattern 9a of the mask 9.

Two patterns 9a are formed on the mask 9.

The two light beams that have passed through 9b are again made into parallel light beams by lenses 10 and 11, and then combined. That is, the first light 30 that has passed through the first pattern 9a has its optical path bent by the mirror 12, and is then combined with the second light 31 that has passed through the lens 11 and the half mirror 13 into a single beam of light. .

Thereafter, using the reduction lens 14, the irradiated sample 15 held on the movable sample stage 16 is irradiated with the two patterns 9a and 9b on the mask 9 combined, and the desired pattern is formed on the irradiated sample 15. A pattern is constructed.

Here, when projecting the desired pattern shown in FIG. We will explain whether the transfer accuracy of the pattern improves.

First, as described above, in consideration of the reduction magnification, the first pattern 32 of the mask 9 is formed into a pattern 32 that has an outer periphery slightly wider than the outer periphery of the desired pattern 29 and has a transparent region inside thereof. Then, the second transmission pattern 36 is a band-shaped transmission pattern 36 that is formed when a shielding pattern 34 of the same size as the desired pattern 29 obtained from the first pattern 32 is subtracted, also taking into account the reduction magnification.

With this configuration, desired pattern 2 can be obtained.
9, the transmitted light from the second transmission pattern 36 and the band-shaped region 3 inside the first transmission pattern 32
The transmitted light from 6' is weakened by light interference, and the boundary of the desired pattern 29 can be sharpened. Further, the desired pattern 29 is located in the shielding region 3 on the second pattern side.
4, and a transmission area 34' on the first pattern side of the same size.
are combined, so the result is the same as normal exposure,
A pattern is formed. In FIG. 2(C), the area irradiated with light is shown by diagonal lines, and the area weakened by interference is shown by a white area 38.
), the pattern is opposite to (b).

FIGS. 5(a) and 5(b) are diagrams showing YY cross-sectional views of the first pattern 9a and the second pattern 9b on the mask 9, respectively. Reference numeral 62 indicates a substrate, and reference numeral 63 indicates a shielding member. FIGS. 5(a') and 5(b') respectively show the amplitude of the light immediately after passing through the mask, and the light (b') that has passed through the phase shift member and It can be seen that there is a phase difference of 180 degrees between the light (a') and the light (a') that does not pass through the phase shift member 5. Figure 5 (C) shows the first pattern and the second pattern.
FIG. 3 is a diagram showing the amplitude of light transmitted through the pattern immediately after being synthesized.

If only the first pattern 32 is used for irradiation, the amplitude of the light on the wafer will be: 'K≠#K Due to the diffraction of the light, the periphery of the pattern will have a gentle slope, and the boundary will not be sharp. However, in this embodiment, the 180
The light 42 with a phase difference of
Since the light beams 29 and 29 are disposed around the light 40 that has passed through the light beams 2, interference weakens each other at the boundaries of the desired pattern 29, resulting in a significant decrease in the light amplitude.

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. 5(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. 5(e).

As described above, according to the mask of this embodiment (first embodiment),
When the desired pattern to be sought is a pattern with a two-dimensional spread, the first
The pattern is a transmission pattern that has a transmission area inside the pattern that is slightly wider than the outer periphery of the two-dimensional pattern (desired pattern), and the second pattern is a band-shaped transmission pattern that has an outer periphery slightly larger than the outer periphery of the first pattern. By forming a pattern, it is possible to sharpen only the boundaries of a desired pattern having a two-dimensional spread.

Note that alignment marks are formed on the mask 9 to align the first pattern 9a and the second pattern 9b. The drive of the alignment mechanism 7 is controlled by this alignment mark.

FIG. 9 is an example of a mark for positioning a pattern divided into two parts. This mark pattern is (a)
and (b) have exactly the same configuration, the same relative position and dimensions. The shape of the mark is not limited to a square as shown in the figure, but shapes such as L-shape and cross-shape can be used. However, in order to increase accuracy, it is better to provide a plurality of the same shapes in different directions. Also, in principle, these alignment marks are used by alignment machines! Mask 9 is provided with only the dimensions required for alignment of 7. In other words, if two-dimensional alignment of the X-Y axes is required, these marks are also required in the two-dimensional direction of the X-Y axes, but normally in the case of a device like the one shown in Fig. is often sufficient.

The transmitted light that has passed through this mark has a phase difference of 180 degrees, and if the positional relationship is correctly aligned, the transmitted light is completely blocked. Therefore, the state of this light shielding may be monitored using a CRT or the like, and when the condition is met, the positioning may be determined to have been completed.

On the other hand, if the light is not completely blocked during initial settings, the alignment mechanism 7 is set so that the light is blocked.
All you have to do is drive and align parts (a) and (b).

Next, a method for manufacturing the mask 9 of this example will be explained with reference to FIG.

The mask 9 of this embodiment shown in FIG. 1 is a mask (reticle) used in a predetermined manufacturing process of a semiconductor integrated circuit device. Note that the mask 9 of this embodiment has an original image of an integrated circuit pattern, for example, five times the actual size, and is composed of a light-shielding area A and a transparent area B.

In manufacturing, first, the surface of a transparent substrate 62 made of quartz glass or the like is polished and cleaned, and then a metal layer 6 made of Cr or the like with a thickness of, for example, about 500 to 3000 is deposited on the surface.
3 is formed by a sputtering method or the like. Next, a photoresist (hereinafter referred to as resist) having a thickness of, for example, 0.4 to 0.8 μm is applied to the upper surface of the metal layer 63 (not shown). Subsequently, after prebaking the resist, a predetermined portion of the resist is irradiated with an electron beam E using an electron beam exposure method or the like based on integrated circuit pattern data of the semiconductor integrated circuit device that is encoded in advance on a magnetic tape (not shown) or the like. Note that the integrated circuit pattern data records the position coordinates, shape, etc. of the pattern.

Next, based on the pattern data of FIGS. 2A and 2B, for example, the patterns shown in FIGS. 2A and 2B are transferred onto a resist (not shown) using an electron beam exposure method or the like.

The pattern data (a) and (b) are 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 this example, (a) indicates the pattern width of the light-shielding area,
For example, pattern data can be automatically created by increasing the thickness by about 0.5 to 2.0 μm, and (b) logically ANDing this with the inverted data of the original data.

After that, through processes such as development, etching of predetermined portions, removal of the resist, further cleaning, and inspection, as shown in FIG. 2(a),
A mask 9 having the pattern shown in (b) is manufactured.

In order to transfer the integrated circuit pattern on the mask 9 onto the irradiated sample 15 (hereinafter simply referred to as a wafer) coated with cysts using the mask 9 manufactured in this way, for example, the following steps are performed. do.

That is, the mask 9 and the wafer are arranged in the reduction projection exposure apparatus shown in FIG. The integrated circuit pattern on the mask 9 is transferred to the entire surface of the wafer by repeating projection exposure each time the wafer is moved in a stepwise manner.

Next, a second embodiment of the mask according to the present invention will be described.

FIGS. 3(a) and 3(b) are diagrams showing the main parts of the mask according to the present invention, and FIGS. 3(a) and 3(b) respectively show the first and second patterns of the mask 9 in FIG. FIG. 3 is a plan view in which mask patterns are divided while maintaining a relative positional relationship in consideration of a desired pattern. Note that (C) is a plan view of the combined desired pattern. 6(a) to 6(e) are diagrams for explaining the amplitude and intensity of light transmitted through the transmission area of the mask shown in FIG. 3. FIG. Note that the exposure apparatus and method used are the same as in the previous embodiment.

In the embodiment shown in FIG.
This figure shows a pattern configuration on a mask for sharpening the boundaries of a one-dimensional pattern in which the patterns are lined up in a row in the horizontal direction. In this case, line 44 among the lines 44 to 47 is
．． Transmissive area 49.50 of the first pattern constituting 46
Transmissive area 5 of the second pattern forming the line 45°47
1°52 are arranged alternately. Then, the area where the lines interfere and weaken each other comes to the intermediate area 55 between the lines constituting the desired pattern 48, and each line becomes sharp.

In FIGS. 6(a) to 6(e), the relationship will be explained in the case where only lines 44 and 45 of the desired pattern are left blank.

In this case as well, a phase difference of 180 degrees occurs between the light 56 that has passed through the transmission area 49 of the first pattern and the light 57 that has passed through the transmission area 51 of the second pattern (see FIG.
a'), (b')). Therefore, in the desired pattern on the wafer, the light components shown at 59.60 in FIG. 6(d') cancel each other out by interference in the region 55 between the two lines 44.45. Therefore, as shown in FIG. 6(d), the slope 61 of the optical amplitude becomes large. Therefore, a sharp boundary can be formed in the area between lines 44 and 45 shown in FIG. Note that FIG. 6(d') is a diagram schematically showing the amplitude of light on the wafer before interference.

As a result, the contrast of the projected image of the one-dimensional pattern can be significantly improved, and the resolution and depth of focus can be significantly improved (FIG. 6(e)).

According to this embodiment, when the desired pattern is a one-dimensional pattern in which lines are lined up in a row in the horizontal direction, the transmission of the first pattern constituting the lines at a relative position on the mask By arranging the regions and the transparent regions of the second pattern alternately, and arranging the regions that interfere and weaken each other in the middle of each line constituting the desired pattern,
When a plurality of lines are lined up in an area so narrow that the two-dimensional pattern method cannot be applied, the transfer accuracy can be greatly improved.

Next, a third embodiment of the mask according to the present invention will be described.

FIGS. 4(a) and 4(b) are diagrams showing the main parts of the mask according to the present invention, and FIGS. 4(a) and 4(b) respectively show the first and second patterns of the mask 9 in FIG. FIG. 3 is a plan view in which mask patterns are divided while maintaining a relative positional relationship in consideration of a desired pattern. Note that (C) is a plan view of the combined desired pattern. FIGS. 7(a) to 7(e) are diagrams for explaining the amplitude and intensity of light transmitted through the transmission area of the mask shown in FIG. 4. Note that the exposure apparatus and method used are the same as in the previous embodiment.

The desired pattern 69 of this embodiment is a square mask pattern 70 with minute sub-patterns 72 arranged around it.

It was difficult to accurately transfer such minute sub-patterns 72 around the two-dimensional pattern 70 using the conventional method of attaching a phase transparent film to a mask, but according to the present invention, it is easy to transfer the fine sub-patterns 72 around the two-dimensional pattern 70. A desired pattern 69 can be created. That is, in the mask of this embodiment shown in FIG. 4 as well, the first pattern is set as a pattern 74 having a transparent area of the same size as the two-dimensional pattern 70 in consideration of its reduction magnification at the relative position on the mask. , by making the second pattern the minute pattern 76, FIG.
As shown in a) to (e), in each transmission region of the mask, there is a phase difference of 180 degrees between the light 77 that has passed through the phase shift member and the light 78 that has not passed through the phase shift member 5. (Fig. 7 (a'), (b')), and these lights interfere in the region 80 between the two-dimensional pattern and the micropattern, thereby reducing the blur of the image projected onto the wafer. becomes possible. As a result, the contrast of the projected image can be significantly improved, and the resolution and depth of focus can be significantly improved (7th
Figure (e)).

According to the masks according to the first to third embodiments, the following effects can be obtained.

During exposure, at the boundary where desired pattern accuracy is required, the light transmitted through the transmission area of the first pattern and the second pattern are separated.
Since the first pattern and the second pattern are configured so that the light transmitted through the transmission area of the pattern interferes and weakens each other, blurring of the outline of the image projected onto the wafer is reduced. , the contrast of the projected image is greatly improved,
Resolution and depth of focus can be significantly improved.

As a result, even if the same wavelength is used with the same projection lens as in the past, the resolution limit can be significantly increased. Therefore, 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 can be greatly improved. It becomes possible to improve the performance.

In addition, because two patterns are prepared and the combined pattern produces a phase shift effect, there is no transparent film on the mask surface, and inspections similar to those in which a conventional transparent film is provided on the mask can be performed. The above inconvenience will be eliminated.

Furthermore, since there is no step of attaching a transparent film, the manufacturing time of the mask can be significantly reduced compared to a mask using a transparent film on the mask substrate as a phase shift means.

Although the invention made by the present inventor has been specifically explained above based on Examples, it goes without saying that the present invention is not limited to the above Examples and can be modified in various ways without departing from the gist thereof. Nor.

For example, the exposure method using a mask of the present invention is not limited to the specific configuration of the apparatus, and is not limited to the configuration of the above-described embodiment in which the luminous flux is divided into two, but the luminous flux is divided into a plurality of parts, It is also possible to provide a means for combining and exposing patterns of a plurality of masks, each with a phase difference.

In the above description, the invention made by the present inventor was mainly explained in terms of the semiconductor device manufacturing technology, which is the field of application behind the invention, but the present invention is not limited thereto. It is clear that the improvement effect can be widely applied to the technical field of exposure.

[Effects of the Invention] The effects obtained by typical inventions disclosed in this application are briefly explained below.

That is, at the boundary where desired pattern accuracy is required, the light transmitted through the transmission area of the first pattern and the light transmitted through the transmission area of the second pattern interfere and weaken each other. The first pattern and the second pattern on the mask forming the first pattern and the second pattern have at least partially coherent two patterns having a phase difference, respectively.
Since the desired pattern is created on the irradiated sample by irradiating two lights and combining the transmitted patterns of those lights, it is possible to improve the transfer accuracy at the boundary where the precision of the desired pattern is required. can.

[Brief explanation of the drawing]

FIG. 1 is a configuration diagram of the main parts of an exposure optical system which is an embodiment of the present invention, FIGS. 2(a) and 2(b) are plan views of the main parts showing an example of the pattern structure of the mask shown in FIG. (C) is a plan view of the desired pattern created by these patterns; FIGS. 3(a) and 3(b) are plan views of essential parts each showing an example of the pattern configuration of the mask in FIG. 1; (C) is a plan view of the desired patterns. FIGS. 4(a) and 4(b) are plan views of essential parts showing an example of the pattern configuration of the mask shown in FIG. 1, and FIG. 4(C) is a plan view of the desired pattern created by these patterns. Plan view, Figures 5(a) to (e) are explanatory diagrams showing the amplitude and intensity of light transmitted through the transmission area of the mask in Figure 2, Figure 6(a)
- (e) and (d') are explanatory diagrams showing the amplitude and intensity of light transmitted through the transmission area of the mask shown in Fig. 3, and Figs. An explanatory diagram showing the amplitude and intensity of light transmitted through the transmission region, FIG. 8 is a cross-sectional view of the mask, and FIGS. Explanatory diagram, Figures 10 (a) to (d)
) is a diagram for explaining a method using a conventional mask that does not use a phase shift method, and Figures 11 (a) to (d) are diagrams for explaining a method using a conventional mask that uses a phase shift method. FIG. 1...at least partially coherent light source, 2
... Beam expander, 3, 6. 12 ... Mirror, 4, 13 ... Half mirror 5 ... Optical phase shift member, 7 ... Alignment mechanism, 8 ...
・Control circuit, 10.11... Optical lens, 9...
-Mask, 9a, 9b--1st. 2nd pattern, 14
...Reduction lens, 15...Irradiated sample (wafer), Fig. Fig. (a) (b) (C) Fig. (C) 70' Fig. (C) (e) ? ! ! 'i4 [ Figure (b) Figure (C) Figure (bl Ma Figure (C) (d) (e) Figure Figure (b) (C) Figure ↓ Good cI Figure ゛2- eye

Claims (1)

[Claims] 1. A first pattern and a second pattern each having a light-blocking area and a transmitting area, and at least partially coherent two beams having a phase difference between the two types of patterns. A mask for creating a desired pattern on an irradiated sample by irradiating light and synthesizing the transmission patterns of those lights, the mask comprising: a mask for creating a desired pattern on an irradiated sample;
The light transmitted through the transmission area of the pattern and the light transmitted through the transmission area of the second pattern interfere and weaken each other.
A mask characterized in that the first pattern and the second pattern are formed on the same substrate, or the first pattern and the second pattern are formed separately on two substrates. 2. A light source that generates an at least partially coherent light beam, a light beam splitting means for splitting the coherent light beam into two, and a light path from the light beam splitting means to recombining the light beam. an optical phase shift member placed thereon, an optical system that combines the light beams transmitted through the first pattern and the second pattern into a single light beam, and an optical system that reduces and projects the single light beam onto the irradiated sample. The optical phase shift member shifts the phase of the light passing through the first pattern and the light passing through the second pattern by up to 180 degrees to create a combined desired pattern on the irradiated sample. An exposure apparatus using a mask, characterized in that: 3. Irradiating the first pattern and the second pattern on the mask according to claim 1 with two at least partially coherent lights each having a phase difference, and combining the transmission patterns of the lights. , an exposure method using a mask, which is characterized by creating a desired pattern on a sample to be irradiated.