JPH11102063A - Production of mask and production of semiconductor device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the transfer accuracy of intricate and fine patterns formed on an optical mask by patterning the phase shift film on a mask substrate to the shapes resembling the plane shape with the circuit patterns to be formed on a semiconductor wafer or the inversion patterns thereof. SOLUTION: Metallic layers 3 are patterned and formed to prescribed shapes on the main surface of the mask substrate 2 constituting a mask 1a. The original picture of integrated circuit patterns is composed of light shielding regions A and transmission regions B. The one transmission region B comprises a part coated with a transparent film (a) and a part not formed with this transparent film 4a. At the time of exposure, a phase difference of 180 deg. is induced between the phase of the light transmitted through the transparent film 4a out of the light which is cast on the mask 1a and is transmitted through the one transmission region B and the phase of the light transmitted through the ordinary transmission regions B. These light rays weaken each other in the boundary parts between the light shielding regions A and the transmission regions B and, therefore, unsharpness is reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a mask and a technique of manufacturing a semiconductor device, and more particularly to a technique effective when applied to an exposure technique of transferring a predetermined integrated circuit pattern using an optical mask. is there.

[0002]

2. Description of the Related Art In recent years, in semiconductor integrated circuits, the elements and wirings constituting the circuits have been miniaturized, and the spacing between elements and wirings has been reduced.

[0003] However, the miniaturization of such elements and wiring,
In addition, as the spacing between elements and the spacing between wirings are becoming narrower, the pattern transfer accuracy of a mask for transferring an integrated circuit pattern onto a semiconductor wafer (hereinafter, referred to as a wafer) is being reduced by irradiation of at least partially coherent light. .

This will be described below with reference to FIGS. 18 (a) to 18 (d).

That is, the mask 50 shown in FIG.
When the above predetermined integrated circuit pattern is transferred onto a wafer (not shown) by a projection exposure method or the like, the phase of the light transmitted through each of the pair of transmission regions P1 and P2 sandwiching the light shielding region N is
Since the phases are in-phase as shown in FIG. 18B, as shown in FIG. 18C, these interference lights reinforce each other in the light shielding region N sandwiched between the pair of transmission regions P1 and P2. .

For this reason, as shown in FIG. 18D, the modulation of the light intensity distribution on the wafer (modula
) is reduced, and the pattern transfer accuracy of the mask is greatly reduced.

As a means for solving such a problem, for example, a phase shift mask for producing a phase difference between light transmitted through each of a pair of transmission regions has been proposed.

[0008] A phase shift mask is described in, for example, Japanese Patent Publication No. 62-59296. In the above-mentioned publication, at least a pair of transmission regions sandwiching the light-shielding region in a mask having a light-shielding region and a transmission region is disclosed. A transparent material is provided on one side, and a phase difference is generated between light transmitted through each transmission area during exposure, so that these lights do not interfere with each other and strengthen each other in an area which is originally a light shielding area on the wafer. The described mask structure is described.

The function of transmitted light in such a mask will be described below with reference to FIGS.

That is, the mask 51 shown in FIG.
When the above predetermined integrated circuit pattern is transferred onto a wafer (not shown) by a projection exposure method or the like, of the pair of transmission regions P1 and P2 sandwiching the light shielding region N, the transmission region P2 provided with the transparent material 52 is provided. 19B and the phase of the light transmitted through the normal transmission region P1 between the phase of the light transmitted through
As shown in (c), a phase difference of 180 degrees occurs.

Therefore, the light transmitted through the pair of transmission regions P1 and P2 interferes with each other in the light-shielding region N sandwiched between the transmission regions P1 and P2, and cancels each other.
As shown in (d), the modulation of the light intensity distribution on the wafer is improved, and the pattern transfer accuracy of the mask 51 is improved.

[0012]

A conventional technique for producing a phase difference between light transmitted through a pair of transmission regions is that when a pattern is simply and repeatedly arranged one-dimensionally, a transparent pattern is formed. The present inventors have found that there is no problem in the arrangement of the materials, but the following problems occur when the patterns are two-dimensionally arranged like an actual integrated circuit pattern.

That is, in the prior art, a transparent material is disposed so that a phase difference is generated between light transmitted through each of the pair of transmission regions. In other words, the transparent material is disposed on one of the pair of transmission regions. If it is arranged, a transparent material cannot be arranged on the other side. Therefore, when the pattern shape is complicated like an actual integrated circuit pattern, a pattern in which a sufficient resolution cannot be obtained partially occurs. For example, when there is an integrated circuit pattern 53 as shown in FIG.
If a transparent material is provided in the light-transmitting region 2, the resolution of the light-shielding regions N1 and N2 can be improved, but the transmission region P1 or the transmission region P3 can be improved.
Cannot provide a transparent material, the resolution of the light shielding region N3 cannot be improved.

An object of the present invention is to provide a technique capable of improving the transfer accuracy of a complicated and fine pattern formed on an optical mask.

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

[0016]

SUMMARY OF THE INVENTION Among the inventions disclosed in the present application, the outline of a representative one will be briefly described.
It is as follows.

That is, the method of manufacturing a mask according to the present invention comprises:
Light is applied to a mask having a first light transmission region and a second light transmission region that is in contact with the first light transmission region and in which the phase of the transmitted light is inverted with respect to the phase of the light transmitted through the first light transmission region. Irradiating a circuit pattern on a semiconductor wafer by a reduction projection exposure apparatus, wherein a phase of transmitted light is inverted with respect to a phase of light transmitted through the mask substrate. Patterning the phase shift film on the mask substrate on which the phase shift film is formed such that the planar shape is similar to a circuit pattern to be formed on the semiconductor wafer or an inverted pattern thereof. Have

Further, a method of manufacturing a semiconductor device according to the present invention
A phase shift film is formed on the mask substrate so that the phase of the transmitted light is inverted with respect to the phase of the light transmitted through the mask substrate, and the phase shift film is a circuit pattern to be formed on a semiconductor wafer or a circuit pattern thereof. A mask that has been patterned so as to have a pattern similar to a planar shape is irradiated with light using a reduction projection exposure apparatus, and a region where the phase shift film is formed and a region where the phase shift film is formed The semiconductor wafer is exposed to a circuit pattern by interference of light transmitted through a region which is in contact with the region where the phase shift film is not formed and which is not formed with the phase shift film.

[0019]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below in detail with reference to the drawings. (Note that components having the same functions in all drawings for describing the embodiments are denoted by the same reference numerals.) , And the repeated explanation is omitted).

(Embodiment 1) FIG. 1 is a sectional view of a principal part of a mask according to an embodiment of the present invention, and FIGS. 2A to 2C are sectional views of a principal part showing a manufacturing process of the mask. FIG. 3
3A is a cross-sectional view showing an exposure state of the mask shown in FIG. 1, and FIGS. 3B to 3D are explanatory views showing the amplitude and intensity of light transmitted through a transmission region of the mask.

The mask 1a of the first embodiment shown in FIG.
For example, in a predetermined manufacturing process of a semiconductor device, a reticle (hereinafter, referred to as a reticle (hereinafter referred to as a reticle) in which a predetermined integrated circuit pattern is transferred onto a wafer (not shown) and an original of an integrated circuit pattern having a size five times the actual integrated circuit pattern is formed Double reticle).

A transparent mask substrate (hereinafter, simply referred to as a substrate) 2 constituting the mask 1a has, for example, a refractive index of 1.47.
Of synthetic quartz glass, on its main surface, for example,
A metal layer 3 having a thickness of 500 to 3000 mm is patterned in a predetermined shape.

The metal layer 3 is composed of, for example, a Cr layer or a Cr oxide layer laminated on the Cr layer.
At the time of exposure, it becomes the light-shielded area A. Further, the portion from which the metal layer 3 has been removed becomes a transmission region B during exposure. The light shielding area A and the transmission area B constitute an original image of the integrated circuit pattern.

In the first embodiment, the transparent film 4a is formed so as to be slightly wider than the pattern width of the metal layer 3 described above. That is,
On the mask 1a, a transparent film 4a that is partially protruded from the contour of each metal layer 3 to the transmission region B is pattern-formed. In other words, one transmission region B is constituted by a portion covered with the transparent film 4a and a portion where the transparent film 4a is not formed.

The transparent film 4a is made of indium oxide (InO).
X). For example, when the pattern width of the transmission region B is 2 μm, the width of the protruding transparent film 4 a is 0.5 μm.
m.

Now, suppose that the thickness of the protruding transparent film 4a from the main surface of the substrate 2 is X1, the refractive index of the substrate 2 is n,
Assuming that the wavelength of the light irradiated upon exposure is λ, the transparent film 4
a is formed such that its thickness X1 satisfies the relationship X1 = .lambda ./ [2 (n-1)]. This is the exposure
The phase difference of 180 degrees between the phase of the light transmitted through the transparent film 4a and the phase of the light transmitted through the normal transmission area B among the light irradiated on the mask 1a and transmitted through one transmission area B is shown. It is to cause it. For example, assuming that the wavelength λ of the light irradiated upon exposure is 0.365 μm (i-line) and the refractive index of the transparent film 4a is 1.5, the thickness X1 of the transparent film 4a from the main surface of the substrate 2 is X1. Should be about 0.37 μm.

Although not shown, the mask 1a includes:
For example, when forming the transparent film 4a, an alignment mark for alignment with the metal layer 3 is formed.

Next, a method of manufacturing the mask 1a according to the first embodiment will be described with reference to FIGS.

First, as shown in FIG. 2A, on the main surface of the polished and cleaned transparent substrate 2, for example, a thickness of 500 to
A metal layer 3 made of Cr or the like of 3000 ° is formed by a sputtering method or the like, and then, for example, a photoresist 5a of 0.4 to 0.8 μm is applied on the upper surface of the metal layer 3.

Then, after pre-baking the photoresist 5a, based on pattern data in which the position coordinates, shape, and the like of the integrated circuit pattern of the semiconductor device, which are previously encoded and recorded on a magnetic tape (not shown), are stored.
A predetermined portion of the photoresist 5a is irradiated with an electron beam E by an electron beam exposure method or the like.

Thereafter, as shown in FIG. 2B, the exposed portions of the photoresist 5a are removed by a predetermined developing solution.
The exposed metal layer 3 is etched by a dry etching method or the like to form a pattern in a predetermined shape.

Then, the photoresist 5a is removed with a resist stripper, and the substrate 2 is washed and inspected.
As shown in (c), a transparent film 4 a made of indium oxide (InO _x ) or the like having a thickness of about 0.37 μm from the main surface of the substrate 2 is coated on the main surface of the substrate 2 so as to cover the metal layer 3. It is formed by a sputtering method or the like.

Next, on the upper surface of the transparent film 4a, for example,
A photoresist 5b having a thickness of 4 to 0.8 μm is applied, and further, for example, a 0.05 μm thick aluminum (A
The antistatic layer 6 of 1) is formed by a sputtering method or the like.

Thereafter, in the pattern data of the integrated circuit pattern described above, the transparent film 4a obtained by enlarging or reducing the width of the pattern of the light shielding area A or the transmission area B is used.
Based on the pattern data, for example, the photoresist 5 in a portion where the transparent film 4a is left by an electron beam exposure method or the like.
b is irradiated with an electron beam E and exposed.

In the first embodiment, the pattern data of the transparent film 4a is automatically created by, for example, increasing the pattern width of the light shielding area A. That is, the pattern data of the transparent film 4a is not created specially as in the case of creating the pattern data of the integrated circuit pattern, but is created based on the pattern data of the integrated circuit pattern.

After exposing the photoresist 5b, development, etching of a predetermined portion of the transparent film 4a, removal of the photoresist 5b, cleaning, inspection, and the like are performed, and the mask 1a shown in FIG. 1 is manufactured. .

Using the mask 1a manufactured as described above, the mask 1 is placed on the wafer coated with the photoresist.
To transfer the integrated circuit pattern on a, for example, the following is performed.

That is, the mask 1a and the wafer are arranged in a reduction projection exposure apparatus (not shown), and the original image of the integrated circuit pattern on the mask 1a is optically reduced to 1/5 and projected onto the wafer. Are repeatedly projected and exposed each time the wafers are sequentially moved stepwise, thereby transferring an integrated circuit pattern over the entire surface of the wafer.

Next, the operation of the first embodiment will be described with reference to FIG.
This will be described with reference to (d).

In the mask 1a of the first embodiment shown in FIG. 3A, when an original image of a predetermined integrated circuit pattern on the mask 1a is transferred onto a wafer by a reduced exposure method or the like, each of the masks 1a In the transmission area B, the transparent film 4
A phase difference of 180 degrees occurs between the light transmitted through a and the light transmitted through the normal transmission region B (FIG. 3B,
(C)).

Since the transparent film 4a is disposed at the end of each metal layer 3, the light transmitted through the transparent film 4a and the light transmitted through the transparent film 4a out of the light transmitted through one transmission region B are used. The transmitted light is transmitted to the light shielding areas A and A adjacent to the transmission area B.
Weaken each other at the border.

Therefore, the modulation of the light intensity distribution on the wafer is greatly improved (FIG. 3).
(D)). In particular, blurring at the end of each light shielding area A projected on the wafer is greatly reduced, and the pattern transfer accuracy can be greatly improved. Since the light intensity is the square of the light amplitude, the waveform on the negative side of the light amplitude on the wafer is inverted to the positive side as shown in FIG.

The conventional technique is a technique for generating a phase difference between light transmitted through a pair of transmission areas, in other words, a technique for producing one action in two transmission areas.

As described in the problem to be solved by the invention, when the pattern is complicated and two-dimensionally arranged like an actual integrated circuit pattern, the pattern transfer accuracy is partially reduced. Of the transparent material is restricted.

That is, it was very difficult to arrange a transparent material so as to improve the accuracy of transferring all the patterns on the mask.

Therefore, the pattern data of the transparent material cannot be automatically created. When the pattern data is created, the pattern data for the transparent material is taken into consideration while considering the arrangement so that the pattern transfer accuracy is not partially reduced. Must be designed, drawn and computerized to create this pattern.

On the other hand, the mask 1 of the first embodiment
In the technique a, the phase difference is generated in the light transmitted through one transmission area to improve the pattern transfer accuracy. Therefore, even if the pattern formed on the mask 1a is complicated, The transparent film 4a can be arranged.

For this reason, the arrangement of the transparent film 4a is easy, and the pattern data of the transparent film 4a is automatically created based on the pattern data of the light shielding area A or the transmission area B constituting the integrated circuit pattern. It becomes possible.

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

(1) In each transmission region B 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, and these light Are weakened at the boundary between the light shielding area A and the transmission area B, so that the modulation of the light intensity distribution on the wafer is greatly improved. In particular, blurring at the end of the pattern image in the light-shielded area A projected on the wafer is greatly reduced, and the pattern transfer accuracy can be greatly improved.

(2) According to the above (1), even if the pattern formed on the mask is a fine and complicated integrated circuit pattern, the pattern transfer accuracy is not partially reduced, and Transfer accuracy can be improved.

(3) Since the transparent film 4a for shifting the phase is a technology that considers only the phase difference of the light transmitted through one transmission region B, even if it is a complicated integrated circuit pattern, its arrangement is not changed. It will be easier.

(4) According to the above (3), the pattern data of the transparent film 4a is transferred to the light shielding area A,
Alternatively, it can be automatically created based on the pattern data of the transmission region B.

(5) According to the above (3) and (4), the pattern data of the transparent film 4a can be created in a short time.
Mask 1a on which transparent film 4a for shifting the phase is formed
Can greatly reduce the manufacturing time.

(Embodiment 2) FIG. 4 is a sectional view of a main part of a mask according to another embodiment of the present invention, and FIGS. 5 (a) and 5 (b).
FIG. 6 is a sectional view of a main part of the mask showing a manufacturing process of the mask, FIG. 6 is a configuration diagram of a focused ion beam apparatus used in manufacturing the mask, and FIG. 7A shows an exposure state of the mask shown in FIG. FIGS. 7B to 7D are explanatory views showing the amplitude and intensity of light transmitted through the transmission region of the mask.

In the mask 1b according to the second embodiment shown in FIG. 4, as a means for generating a phase difference in the light transmitted through the transmission region B at the time of exposure, instead of the transparent film 4a according to the first embodiment, At the time of exposure, a phase shift groove 7a is formed in the substrate 2 which becomes the transmission region B.

During the exposure, the phase shift groove 7a is formed along the edge of the metal layer 3 which becomes the light shielding area A, that is, the metal layer 3
Are formed along the outline of the. The width of the phase shift groove 7a is, for example, about 0.5 μm when the pattern width of the transmission region B is 2 μm.

Assuming that the depth of the phase shift groove 7a is d, the refractive index of the substrate 2 is n, and the wavelength of light irradiated during exposure is λ, the phase shift groove 7a has a depth d. But,
It is formed so as to satisfy the relationship of d = λ / [2 (n−1)]. This is because, in the light transmitted to the mask 1b, the phase of the light transmitted through the phase shift groove 7a and the phase of the light transmitted through the normal transmission area B in each of the transmission regions B in the light irradiated on the mask 1b. This is for generating a phase difference of 180 degrees. For example, the wavelength λ of the light irradiated at the time of exposure is set to 0.3.
If it is 65 μm (i-line), the depth d of the phase shift groove 7a
Should be about 0.39 μm.

Although not shown, the mask 1b has
When forming the phase shift groove 7a, an alignment mark for alignment with the metal layer 3 is formed.

Next, a focused ion beam apparatus 8 used for manufacturing the mask 1b will be described with reference to FIG.

Although not shown, for example, gallium (Ga) is provided inside the ion source 9 provided on the upper part of the apparatus main body.
Etc. are stored. An extraction electrode 10 is provided below the ion source 9, and a first lens electrode 1 formed by an electrostatic lens is provided below the extraction electrode 10.
1a and a first aperture electrode 12a are provided. Below the aperture electrode 12a, a second lens electrode 11b, a second aperture electrode 12b,
A blanking electrode 13 for controlling N and OFF, a third aperture electrode 12c, and a deflection electrode 14 are provided.

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 deflecting electrode 14, and the mask 1 b before pattern formation held by the holder 15 is formed. Is to be irradiated.

The ion beam is scanned at the time of scanning.
For example, by setting the beam irradiation time and the number of scans in advance for each pixel unit of 0.02 × 0.02 μm,
The metal layer 3 or the substrate 2 can be etched.

The holder 15 is set on a sample table 16 movable in the X and Y directions. The sample table 16 is controlled by a laser interferometer 18 via a laser mirror 17 provided on the side. The position is recognized, and the position is adjusted by the sample stage drive motor 19.

A secondary ion / secondary electron detector 20 is provided above the holder 15, so that the generation of secondary ions and secondary electrons from the workpiece can be detected. ing. An electron shower radiator 21 is provided above the secondary ion / secondary electron detector 20 so that the workpiece can be prevented from being charged.

The inside of the processing system described above has a structure in which a vacuum state is maintained by a vacuum pump 22 shown below the sample table 16 in the figure.

The operation of each of the above-described processing systems is controlled by each of the control units 23 to 27 provided outside the apparatus main body, and each of the control units 23 to 27 further includes each of the interface units 28 to 32. Control computer 3 via
3 is controlled. The control computer 33 includes a terminal 34, a magnetic disk device 35 for recording data, and an MT deck 36.

Next, a method of manufacturing the mask 1b will be described with reference to FIG.
This will be described with reference to (a) and (b) and FIG.

First, as shown in FIG. 5A, a metal layer 3 of, for example, 500 to 3000 ° is formed on the main surface of the polished and cleaned substrate 2 by a sputtering method or the like, and then the focused ion beam It is held by the holder 15 of the device 8.

Next, an ion beam is emitted from the ion source 9, and the ion beam is emitted from each of the electrodes by, for example,
If the beam is focused to a beam diameter of 0.5 μm, an ion beam current of about 1.5 μA can be obtained, and a predetermined portion of the metal layer 3 is formed on the basis of the pattern data of the integrated circuit pattern previously recorded on the magnetic tape of the MT deck 36. The metal layer 3 is etched by irradiating the focused ion beam. At this time, the irradiation time per pixel is, for example, 3 × 10 −6 seconds, and the number of beam scans is about 30 times. Thus, FIG.
As shown in (b), the metal layer 3 is patterned.
The pattern formation of the metal layer 3 may be performed by an electron beam exposure method as in the first embodiment.

After that, a predetermined amount of ion beam is irradiated on a positioning mark (not shown) formed on the mask 1b.
The generated secondary electrons are detected by the secondary ion / secondary electron detector 20, and the position coordinates of the alignment mark are calculated based on the detected data.

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 at the time of ion beam irradiation.

Next, based on the pattern data of the phase shift groove 7a, the substrate 2 exposed by the pattern formation of the metal layer 3 along the edge of the metal layer 3 is irradiated with an ion beam, and the phase shift groove 7a (FIG. ) Is formed. At this time, according to the focused ion beam, the depth, width, and the like of the phase shift groove 7a can be easily controlled.

In the second embodiment, the pattern data of the phase shift groove 7a is, for example, the pattern data of the transmissive area B obtained by inverting the pattern data of the integrated circuit pattern in the positive / negative manner, and the pattern data of the light shielding area A. AND (AND) with pattern data obtained by increasing the width
D) is automatically created.

That is, the pattern data of the phase shift groove 7a is not automatically created, but is automatically created based on the pattern data of the integrated circuit pattern.

Using the mask 1b manufactured as described above, the mask 1b is placed on the wafer coated with the photoresist.
To transfer the integrated circuit pattern on b, for example, the following is performed.

That is, the mask 1b and the wafer are arranged in a reduction projection exposure apparatus (not shown), and the integrated circuit pattern on the mask 1b is optically reduced to 1/5 and projected onto the wafer. The transfer of the integrated circuit pattern is performed on the entire surface of the wafer by repeatedly performing projection exposure each time the wafer is moved in a step shape.

Next, the operation of the mask 1b according to the second embodiment will be described with reference to FIGS.

In the exposure step of transferring the original image of the predetermined integrated circuit pattern on the mask 1b shown in FIG. 7A, the light transmitted through the phase shift groove 7a and the light transmitted through the phase shift groove 7a in each transmission region B of the mask 1b A phase difference of 180 degrees is generated between the light and the light transmitted through the transmission region B (FIG. 7B,
(C)).

The phase shift groove 7a is formed in each metal layer 3
Of the light transmitted through one transmission region B, the light transmitted through the phase shift groove 7a and the light transmitted through the normal transmission region B out of the light transmitted through one transmission region B are light-shielded adjacent to the transmission region B. The regions A, A weaken each other at the boundary.

Therefore, the modulation of the light intensity distribution on the wafer is greatly improved (FIG. 7D). In particular, blurring at the end of each light shielding area A projected on the wafer is greatly reduced, and transfer accuracy of the pattern projected on the wafer is greatly improved.

Since the light intensity is the square of the light amplitude, the waveform on the negative side of the light amplitude on the wafer is shown in FIG.
As shown in (d), it is inverted to the positive side.

Also, in the mask 1b according to the second embodiment, similar to the first embodiment, only the phase difference in the light transmitted through one transmission region B is taken into account. Even if a complicated integrated circuit pattern is formed, the arrangement of the phase shift groove 7a is easy, and the pattern data of the phase shift groove 7a is determined based on the pattern data of the light shielding area A or the transmission area B constituting the integrated circuit pattern. Automatically.

Moreover, in the mask 1b of the second embodiment, there is no step of forming the transparent film 4a for shifting the phase described in the first embodiment when manufacturing the mask 1b. When patterning, a phase shift groove 7a is also formed, so that the manufacturing time can be further reduced.

According to the second embodiment, the following effects can be obtained.

(1) In each transmission area B of the mask 1b, 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 area B, and these lights are generated. Are weakened at the boundary between the light shielding area A and the transmission area B, so that the modulation of the light intensity distribution on the wafer is greatly improved. In particular, blurring at the end of the pattern image in the light-shielded area A projected on the wafer is greatly reduced, and the pattern transfer accuracy can be greatly improved.

(2) According to the above (1), even if the pattern formed on the mask is a fine and complicated integrated circuit pattern, the transfer accuracy of the pattern image does not partially decrease, and The transfer accuracy of all the patterns can be improved.

(3) Since the phase shift groove 7a is a technique that considers only the phase difference of light transmitted through one transmission region B, even if it is a complicated integrated circuit pattern, it can be easily arranged. .

(4) According to the above (3), the pattern data of the phase shift groove 7a can be automatically created based on the pattern data of the light shielding area A or the transmission area B constituting the integrated circuit pattern. The mask 1b can be manufactured in a short time.

(5) In the mask 1b, there is no step of forming the transparent film 4a for shifting the phase described in the first embodiment when manufacturing the mask 1b, and the metal layer 3 is patterned by a focused ion beam. At this time, since the phase shift groove 7a is also formed, the manufacturing time can be further reduced.

(6) In the mask 1b, since the transparent film 4a does not deteriorate due to a cleaning process after pattern formation,
Its life can be greatly improved.

(Embodiment 3) FIG. 8 is a sectional view of a principal part of a mask according to still another embodiment of the present invention, FIG. 9 is a plan view of the principal part of this mask, and FIG. 9 is a cross-sectional view showing an exposure state of the mask in FIG. 9, and FIGS. 10B to 10D are explanatory views showing the amplitude and intensity of light transmitted through the transmission region of the mask.

First, the mask 1c according to the third embodiment will be described with reference to FIGS. In the third embodiment, the shape of the transmission region B is rectangular as shown in FIG.

The mask 1c of the third embodiment is, for example,
This is a five-fold reticle for transferring a predetermined integrated circuit pattern onto a wafer (not shown) in a predetermined manufacturing process of the semiconductor device. A plurality of grooves 37 reaching the surface are provided.

As shown in FIG. 9, the grooves 37 are arranged in parallel along each side of the transmission region B so as to surround the rectangular transmission regions B. In addition, for example, the groove 37
Is about 0.5 μm.

Further, a transparent film 4b made of, for example, indium oxide (InO _x ) having a refractive index of 1.5 is provided on the upper portion of the groove 37. When the transparent film 4b is exposed to light,
Further, a phase difference is generated between the light transmitted through the groove 37 and the light transmitted through the transmission region B.

The thickness X2 of the transparent film 4b from the main surface of the substrate 2 is equal to the thickness of the transparent film 4b and the groove 37 of the light applied to the mask 1c during exposure, as in the first embodiment. In order to cause a phase difference of 180 degrees between the phase of the transmitted light and the phase of the light transmitted through the transmission region B, X2 = λ /
It is formed so as to satisfy the relationship of [2 (n-1)]. For example, the wavelength λ of the light irradiated at the time of exposure is set to 0.3.
Assuming that the thickness is 65 μm (i-line), the thickness X2 of the transparent film 4b from the main surface of the substrate 2 may be about 0.37 μm.

Although not shown, the mask 1c includes:
For example, when forming the groove 37 and the transparent film 4b, an alignment mark for aligning them with the metal layer 3 is formed.

To manufacture such a mask 1c, for example, the following is performed.

First, a metal layer 3 of, for example, 500 to 3000 ° is formed by a sputtering method or the like so as to cover the main surface of the polished and cleaned substrate 2, and then the focused ion beam device described in the second embodiment is formed. 8 is held by the holder 15.

Next, based on the integrated circuit pattern data previously recorded on the magnetic tape of the MT deck 36,
The metal layer 3 covering the main surface of the substrate 2 is patterned by an ion beam.

Thereafter, the metal layer 3 on the main surface of the substrate 2 is irradiated with an ion beam based on the pattern data of the groove 37 previously recorded on the magnetic tape of the MT deck 36, and the groove 37 is applied to the metal layer 3. To form The pattern data of the groove 37 is, for example, the groove 3 for the rectangular transmission region B.
By setting the arrangement rule of No. 7, it is automatically created.

Then, based on the pattern data of the transparent film 4b created based on the pattern data of the integrated circuit pattern and the pattern data of the groove 37, the transparent film 4b is formed in the same manner as in the first embodiment.

Next, the operation of the third embodiment will be described with reference to FIG.
This will be described with reference to (d).

When an original image of a predetermined integrated circuit pattern on a mask 1c shown in FIG. 10A is transferred onto a wafer by a reduced exposure method or the like, a transparent film 4b and a groove are formed in each transmission region B of the mask 1c. A phase difference of 180 degrees is generated between the light transmitted through 37 and the light transmitted through transmission region B (FIGS. 10B and 10C).

Then, of the light transmitted through one transmission area B, the light transmitted through the transparent film 4b and the groove 37 and the light transmitted through the transmission area B become light-shielded areas A, Weak at the end of A.

Therefore, the modulation of the light intensity distribution on the wafer is greatly improved (FIG. 10D). In particular, blurring at the end of each light shielding area A projected on the wafer is greatly reduced, and transfer accuracy of the pattern projected on the wafer is greatly improved.

Since the light intensity is the square of the light amplitude, the waveform on the negative side of the light amplitude on the wafer is as shown in FIG.
As shown in (d), it is inverted to the positive side.

Further, also in the mask 1c of the third embodiment, since only the phase difference in the light transmitted through one transmission region B needs to be considered, the arrangement of the groove 37 and the transparent film 4b is easy. The pattern data of the groove 37 and the transparent film 4b can be automatically created based on the pattern data of the rectangular transmission region B constituting the integrated circuit pattern.

According to the present embodiment, the following effects can be obtained.

(1) In each transmissive area B of the mask 1c, a phase difference of 180 degrees occurs between the light transmitted through the transparent film 4b and the groove 37 and the light transmitted through the transmissive area B. Since the light is weakened at the end of the light shielding area A, the modulation of the light intensity distribution on the wafer is greatly improved. In particular, blurring at the end of the pattern image in the light-shielded area A projected on the wafer is greatly reduced, and the pattern transfer accuracy can be greatly improved.

(2) According to the above (1), even if the pattern formed on the mask is a fine and complicated integrated circuit pattern, the pattern transfer accuracy is not partially reduced, and the pattern All transfer accuracy can be improved.

(3) Since the transparent film 4b for shifting the phase and the groove 37 are technologies that take into account only the phase difference of light transmitted through one transmission region B, even a complicated integrated circuit pattern is used. , And its arrangement becomes easy.

(4) According to the above (3), the pattern data of the groove 37 and the transparent film 4b are automatically created based on the pattern data of the light shielding area A or the transmission area B constituting the integrated circuit pattern. be able to.

(5) According to the above (3) and (4), the pattern data of the transparent film 4b can be created in a short time.
The mask 1c on which the transparent film 4b for shifting the phase and the groove 37 are formed can be manufactured in a short time.

(Embodiment 4) FIG. 11 is a cross-sectional view of a main part of a mask showing still another embodiment of the present invention, FIG. 12 is a plan view of the main part of this mask, and FIG. FIG. 13B is a cross-sectional view showing an exposure state of the mask of FIG.
(D) is an explanatory view showing the amplitude and intensity of light transmitted through the transmission region.

First, the mask 1d according to the fourth embodiment will be described with reference to FIGS.

In the mask 1d according to the fourth embodiment,
At the time of exposure, as means for generating a phase difference between light transmitted through the groove 37 and light transmitted through the transmission area B, instead of the transparent film 4b of the third embodiment, the substrate 2 below the groove 37 is used. A phase shift groove 7b is formed.

As in the second embodiment, the depth d of the phase shift groove 7b is set such that the phase of light transmitted through the groove 37 and the phase shift groove 7b in the light irradiated on the mask 1b during exposure is In order to generate a phase difference of 180 degrees with the phase of the light transmitted through the transmission region B, it is formed so as to satisfy the relationship d = λ / [2 (n−1)]. For example, if the wavelength λ of light is 0.365 μm (i-line), the phase shift groove 7
The depth d of b may be about 0.39 μm.

Further, in Embodiment 4, FIG.
As shown in FIG. 2, rectangular sub-transmission regions (in-phase auxiliary transmission regions) C of, for example, 0.5 × 0.5 μm are provided at the four corners of the rectangular transmission region B. This prevents a problem that, with the miniaturization of the integrated circuit pattern, the four corners of the pattern lines formed on the wafer after development do not become right angles and are rounded unlike the original image of the integrated circuit pattern on the mask. That's why. That is, in the integrated circuit pattern, the sub-transmission area C is provided at the corner where the light intensity is most likely to decrease and the distortion is increased,
The light intensity near the corner is increased to correct the projected pattern image.

Although not shown, the mask 1d includes:
For example, when forming the groove 37 and the sub-transmission area C, an alignment mark for aligning them with the metal layer 3 is formed.

In order to manufacture such a mask 1d, the metal layer 3 is etched by an ion beam to form the groove 3d.
When forming the substrate 7, the number of scans of the ion beam may be increased and the substrate 2 may be etched to a depth d.

Next, the operation of the fourth embodiment will be described with reference to FIG.
This will be described with reference to (a) to (d).

When a predetermined integrated circuit pattern original image on the mask 1d shown in FIG. 13A is transferred onto a wafer by a reduction exposure method or the like, a groove 37 and a phase shift groove are formed in each transmission region B of the mask 1d. A phase difference of 180 degrees is generated between the light transmitted through the transmission region 7b and the light transmitted through the transmission region B (FIGS. 13B and 13C).

The light transmitted through the groove 37 and the phase shift groove 7b among the light transmitted through one transmission area B is
The light transmitted through the transmission region B weakens at the ends of the light shielding regions A adjacent to the transmission region B.

Therefore, the modulation of the light intensity distribution on the wafer is greatly improved (FIG. 13D). In particular, the blur at the end of each light-shielding area A projected on the wafer is greatly reduced, and the light intensity near the corner is formed by the sub-transmission area C formed at the corner of the rectangular transmission area B. Is increased, the transfer accuracy of the pattern image projected onto the wafer is further improved.

Since the light intensity is the square of the light amplitude, the waveform on the negative side of the light amplitude on the wafer is as shown in FIG.
As shown in (d), it is inverted to the positive side.

Further, also in the mask 1d of the fourth embodiment, since only the phase difference in the light transmitted through one transmission region B needs to be considered, the arrangement of the groove 37 is easy.
The pattern data of the groove 37 can be automatically created by setting the arrangement rule of the groove 37 with respect to the pattern of the rectangular transparent region B constituting the integrated circuit pattern.

In Embodiment 4, Embodiment 3
In addition to the effects shown in (1) to (5), when manufacturing the mask 1d, there is no step of forming the transparent film 4b for shifting the phase described in the third embodiment. When patterning the layer 3, the phase shift groove 7b can also be formed at the same time, so that the manufacturing time can be further reduced.

In the mask 1d, since the mask 1c in the third embodiment is not deteriorated by a cleaning process after the formation of the transparent film 4b, the life of the mask 1d can be greatly improved.

Although the invention made by the inventor has been specifically described based on the embodiment, the invention is not limited to the embodiment, and various modifications can be made without departing from the gist of the invention. Needless to say,

For example, in the mask of the first embodiment, a case has been described where the transparent film for shifting the phase is arranged so as to partially protrude from the contour of the metal layer into the transmission region. However, the present invention is not limited to this. Instead, for example, a transparent film 4c may be arranged near the center of the transmission region B as in a mask 1e shown in FIG.

Also in this case, FIGS.
As shown in (d), in each of the transmission regions B, B of the mask 1e (FIG. 16A), there is a difference between the light transmitted through the transparent film 4c and the light transmitted through the normal transmission region B. A phase difference of 180 degrees occurs (FIGS. 16B and 16C), and among the light transmitted through one transmission region B, the light transmitted through the transparent film 4c and the light transmitted through the normal transmission region B are different. , The light intensity distribution on the wafer is modulated (modula
is greatly improved (FIG. 16D).

The pattern data of the transparent film 4c in this case may be created by, for example, narrowing the pattern of the light-shielded region obtained by inverting the pattern data of the integrated circuit pattern by negative / negative.

In the mask according to the second embodiment,
Although the case where the phase shift groove is arranged along the edge of the metal layer has been described, the present invention is not limited to this. For example, as shown in a mask 1f shown in FIG. The groove 7c may be formed and arranged. In this case, the same operation as that shown in FIGS. 16B to 16D can be obtained.

For example, in a portion where an integrated circuit pattern is simply arranged such as a memory cell,
As in a mask 1g shown in FIG. 17, a phase shift groove 7d is formed in at least one of a pair of transmissive regions B, B sandwiching a light shielding region A.
May be formed.

This is the same as the conventional technique of providing a transparent film in one of a pair of transmissive regions in terms of shifting the phase of light. However, since no transparent material is provided, the manufacturing time is greatly reduced. In addition, since there is no deterioration due to cleaning or the like after the formation of the transparent material, there is an effect that the life of the mask can be significantly improved.

In the third and fourth embodiments, the case where the transmission area is rectangular has been described. However, the present invention is not limited to this, and it is possible to cope with a complicated shape.

In the first and third embodiments, the case where the transparent film is made of indium oxide has been described. However, the present invention is not limited to this, and magnesium fluoride, polymethyl methacrylate, or the like may be used.

In the above description, the case where the invention made by the present inventor is mainly applied to a mask used in a manufacturing process of a semiconductor device, which is a background of application, has been described. The present invention is applicable to a technical field that requires transferring a fine and complicated pattern onto a predetermined substrate by a photolithography technique.

[0141]

Advantageous effects obtained by typical ones of the inventions disclosed by the present application will be briefly described as follows.
It is as follows.

That is, according to the present invention, the phase shift film is patterned so that the planar shape thereof is similar to the circuit pattern to be formed on the semiconductor wafer or its inverted pattern, so that the pattern of the phase shift film is Since the data can be automatically created based on the pattern data of the integrated circuit pattern, the pattern data of the phase shift film can be created in a short time. For this reason, the manufacturing time of the mask having the phase shift film can be significantly reduced. Therefore, in the manufacturing process of the semiconductor device, by performing the exposure process using the mask, the development period of the semiconductor device can be shortened.

[Brief description of the drawings]

FIG. 1 is a sectional view of a main part of an optical mask according to an embodiment of the present invention.

FIGS. 2A to 2C are main-portion cross-sectional views of the optical mask showing a manufacturing process of the optical mask.

3A is a cross-sectional view illustrating an exposure state of the optical mask of FIG. 1, and FIGS. 3B to 3D are explanatory diagrams illustrating amplitude and intensity of light transmitted through a transmission region of the optical mask. is there.

FIG. 4 is a cross-sectional view of a main part of an optical mask according to another embodiment of the present invention.

FIGS. 5A and 5B are cross-sectional views of a main part of the optical mask showing a manufacturing process of the optical mask.

FIG. 6 is a configuration diagram of a focused ion beam device used when manufacturing the optical mask.

7A is a cross-sectional view illustrating an exposure state of the optical mask of FIG. 4, and FIGS. 7B to 7D are explanatory diagrams illustrating amplitude and intensity of light transmitted through a transmission region of the optical mask. is there.

FIG. 8 is a cross-sectional view of a main part of an optical mask according to still another embodiment of the present invention.

FIG. 9 is a plan view of a main part of the optical mask.

10A is a cross-sectional view showing an exposure state of the optical mask of FIGS. 8 and 9, and FIGS. 10B to 10D show amplitude and intensity of light transmitted through a transmission region of the optical mask. FIG.

FIG. 11 is a cross-sectional view of a main part of an optical mask showing still another embodiment of the present invention.

FIG. 12 is a plan view of a main part of the optical mask.

FIG. 13A is a cross-sectional view of the optical mask of FIGS. 11 and 12, and FIGS. 13B to 13D are explanatory diagrams showing the amplitude and intensity of light transmitted through a transmission region of the optical mask. .

FIG. 14 is a cross-sectional view of a main part of an optical mask according to still another embodiment of the present invention.

FIG. 15 is a sectional view of a main part of an optical mask according to still another embodiment of the present invention.

16A is a cross-sectional view showing an exposure state of the optical mask of FIG. 14, and FIGS. 16B to 16D show amplitude and intensity of light transmitted through a transmission region of the optical mask shown in FIG. FIG.

FIG. 17 is a sectional view of a main part of an optical mask according to still another embodiment of the present invention.

18A is a cross-sectional view illustrating an exposure state of a conventional optical mask, and FIGS. 18B to 18D are explanatory diagrams illustrating amplitude and intensity of light transmitted through a transmission region of the conventional optical mask. is there.

19A is a cross-sectional view illustrating an exposure state of a conventional optical mask, and FIGS. 19B to 19D are explanatory diagrams illustrating amplitude and intensity of light transmitted through a transmission region of the conventional optical mask. is there.

FIG. 20 is a partial plan view showing a conventional optical mask.

[Explanation of symbols]

 1a-1g Mask 2 Mask substrate 3 Metal layer 4a-4c Transparent film 5a, 5b Photoresist 6 Antistatic layer 7a-7d Phase shift groove 8 Focused ion beam device 9 Ion source 10 Extraction electrode 11a, 11b First, second lens Electrodes 12a to 12c First to third aperture electrodes 13 Blanking electrode 14 Deflection electrode 15 Holder 16 Sample table 17 Laser mirror 18 Laser interferometer 19 Sample table drive motor 20 Secondary ion / secondary electron detector 21 Electron Shower radiation unit 22 Vacuum pump 23 to 27 Control unit 28 to 32 Interface unit 33 Control computer 34 Terminal 35 Magnetic disk unit 36 MT deck 37 Groove A Light shielding area B Transmission area C Sub transmission area (in-phase auxiliary transmission area) E Electron beam 50,51 Conventional mask 52 Transparent Shielding region in the transmission region N~N3 conventional mask in charge 53 the integrated circuit pattern P1 to P3 conventional mask

Claims (7)

[Claims] 1. A first light transmitting region, and a second light transmitting region which is in contact with the first light transmitting region and whose phase of transmitted light is inverted with respect to the phase of light transmitted through the first light transmitting region. A method of manufacturing a mask for use in a method of manufacturing a semiconductor device in which a circuit pattern is exposed on a semiconductor wafer by irradiating light to a mask having a mask, wherein a phase of transmitted light is a phase of light transmitted through a mask substrate. The phase shift film on the mask substrate on which the phase shift film that is inverted with respect to the phase is formed such that the planar shape is similar to the circuit pattern to be formed on the semiconductor wafer or the inverted pattern thereof. A method of manufacturing a mask, comprising the step of: 2. The method according to claim 1, wherein the phase shift film is formed of a material different from that of the mask substrate. 3. The method of manufacturing a mask according to claim 2, wherein the phase shift film is formed by interference between light transmitted through the mask substrate and light transmitted through the mask substrate and the phase shift film. A method of manufacturing a mask, characterized by emphasizing a region that does not exist. 4. The method of manufacturing a mask according to claim 1, wherein the first light transmitting region is formed so as to surround the second light transmitting region, and the light transmitted through the first light transmitting region. A method of manufacturing a mask, wherein the second light transmitting region is emphasized by interference with light transmitted through the second light transmitting region. 5. The method for manufacturing a mask according to claim 4, wherein the phase shift film is not formed in the first light transmitting region, and the phase shift film is formed in the second light transmitting region. A method for manufacturing a mask, comprising: 6. A phase shift film is formed on a mask substrate to invert the phase of transmitted light with respect to the phase of light transmitted through the mask substrate, and the phase shift film is to be formed on a semiconductor wafer. A mask that is patterned so that the planar shape thereof is similar to the circuit pattern or its inverted pattern is irradiated with light using a reduction projection exposure apparatus, and a region where the phase shift film is formed, A semiconductor device, wherein a circuit pattern is exposed on the semiconductor wafer by interference of light transmitted through a region which is in contact with a region where a phase shift film is formed and where the phase shift film is not formed. Manufacturing method. 7. The method of manufacturing a semiconductor device according to claim 6, wherein a region on the mask substrate on which the phase shift film is formed and a region in contact with the region on which the phase shift film is formed. The light transmitted through the region where the phase shift film is not formed interferes with each other at the boundary between the region where the phase shift film is formed and the region where the phase shift film is not formed and is weakened. A method of manufacturing a semiconductor device, wherein a region where the phase shift film is not formed is emphasized.