JP2002040624A - Method for producing phase shift mask and phase shift mask - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the problem that conventionally the difference in dimensions of a resist on a wafer corresponding to parts to be etched and parts which are not to be etched, and to provide and etched phase shift mask having a structure which is practical even with respect to strength. SOLUTION: In the method for producing an etched phase shift mask, in which a pattern with light-shielding parts 120A and light transmissive parts 150, 160 is formed on a transparent substrate 110 and transparent substrate parts under the light transmissive parts 150, 160 are etched to a depth d1 and a depth d2 [(d1-d2) is about equal to λ/2(n-1)], there are carried out (a) a first etching step in which transparent substrate parts under the light transmissive parts 150 to be etched to the depth d1 are etched by a prescribed depth D1 by selective dry etching; (b) a second etching step in which the etched transparent substrate parts having the depth D1 are further wet-etched to a depth of λ/2(n-1); and (c) a third etching step in which the transparent substrate parts under all the light transmissive parts are wet-etched.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a photomask and a method for manufacturing the same, and more particularly, to a substrate-engraved phase shift mask and a method for manufacturing the same.

[0002]

2. Description of the Related Art As the progress of photolithography technology for forming finer resist patterns on a wafer is remarkable, as one method for improving the resolution of a projection exposure apparatus, two adjacent transparent portions on a mask are used. The phase shift method has been adopted in which the phases of the light passing through are changed to increase the pattern resolution. According to this method, when a film thickness is d, a refractive index is n, and an exposure wavelength is λ, d = λ / 2 as a shifter for inverting the phase to one of the adjacent light transmitting portions.
Projection exposure is performed on a wafer using a mask (hereinafter, referred to as a phase shift mask) formed so as to satisfy the relationship of (n-1), and light passing through the shifter is transmitted through another adjacent light transmitting portion. Because it is out of phase (shift of 180 degrees) with light,
The light intensity becomes 0 at the pattern boundary, the pattern is separated, and the resolution is improved.

As shown in FIG. 4A, a mask shape for realizing high resolution by the above-mentioned phase shift method is such that one of adjacent openings (light-transmitting portions) 321 is transparent and has a refractive index different from that of air. (Also called phase shift film or shifter)
Although there is a shifter forming type phase shift mask provided with the 330, it is difficult to accurately deposit a phase shift film having the same refractive index as the substrate in the case of this mask. As a phase shift mask that solves these problems,
Fig. 4 (b) in which a transparent substrate is engraved by etching or the like.
There is also a phase shift mask as shown in FIG. 4C (hereinafter also referred to as an engraved or dug-in type phase shift mask). The engraving type phase shift mask shown in FIG. 4B has an engraved portion formed by anisotropic etching. In this mask, the amount of transmitted light is lower than that of the non-engraved portion. The fact that the dimensions of the resist pattern of the projected image are different for the engraved part and the non-engraved part, respectively, is thesis1 (J.Vac.Sc
i.Technol. B 10 (6) (1992) p3055), RL Kostelak
, [Exposure characteristicsof alternate aperture
phase-shifting masks fabricated using a subtracti
ve process]). FIG. 4 (c)
The phase shift mask shown in FIG. 1 has an engraved portion formed by isotropic etching. In this paper, it is described in the above-mentioned article 1 that the degree of the resist dimensional difference in this mask is smaller than that in the mask of FIG. But not enough. The engraving type phase shift mask shown in FIG. 4C is also called a single engraving type phase shift mask, and Wa is a side etching amount. In the case of the engraved phase shift mask shown in FIG. 4B, the amount of light transmitted through the engraved portion is lower than that of the non-engraved portion due to the side wall of the engraved portion. Occurs. In particular, in the case of a hole-based layer, the transmitted light intensities are not equal, and a dimensional difference occurs in the resist pattern on the wafer. This tendency is conspicuous in hole patterns arranged obliquely of 1.0 μm or less. In general, engraving by anisotropic etching is performed by dry etching, and isotropic etching is performed by wet etching with hot alkali or hydrofluoric acid.

As a method of correcting a resist dimensional difference in the case of FIG.
After engraving vertically by a phase difference of 0 degrees (the state shown in FIG. 4 (b)), isotropic etching was applied to the entire light-transmitting portion, and FIG.
The method of forming the phase shift mask shown in (d) is also described in the paper 2 (SPIE. Vol. 1927 (1993) p28, Christophe Pierrat).
Others, [Phase-Shifting Mask Topography Effects on L
ithographic Image Quality]).
The engraved phase shift mask shown in FIG. 4D is also called a double engraved phase shift mask or a double engraved substrate engraved phase shift mask. However, FIG.
In the case of using the phase shift mask of (d), the side etching amount W
b1 and Wb2 become large, and the eaves 325 of the light-shielding member become structurally weak, which causes a defect such as peeling or chipping in a step such as mask cleaning or the like (hereinafter also referred to as a peeling defect). Easy and Wb1
(Wb) of the light-shielding film 120 whose both sides are side-etched is easily peeled off.

[0005]

At present, as a dimension correction mask of the engraving type phase shift mask shown in FIG. 4B, a single engraving type phase shift mask shown in FIG.
Although the double engraving type phase shift mask shown in FIG. 4D is used, as described above, the single engraving type phase shift mask shown in FIG. 4C has both the engraved portion and the non-engraved portion. However, the two-phase engraving type phase shift mask shown in FIG. 4D cannot sufficiently solve the problem of the difference in the size of the resist on the wafer. The sum of Wb1 and Wb2 (referred to as Wb) becomes large, and there is a problem of occurrence of a defect (hereinafter, also referred to as a peeling defect) such that this portion is peeled or chipped in a step of mask cleaning or the like. In addition, the entire light-shielding film 120 where both sides are side-etched is peeled off, which is a problem. The present invention corresponds to this, and can solve the problem of the dimensional difference of the resist on the wafer corresponding to the engraved portion and the non-engraved portion, respectively, and has an engraved type of a structure that is practical in terms of strength. It is intended to provide a phase shift mask. At the same time, it is an object of the present invention to provide a method for manufacturing such a phase shift mask of the substrate engraving type.

[0006]

According to a method of manufacturing a phase shift mask of the present invention, a light-shielding portion for shielding exposure light and a light-transmitting portion on a transparent substrate having a refractive index n transparent to exposure light of wavelength λ. Is formed, and the transparent substrate portion of the light-transmitting portion is carved. One of the concave portions has a depth of d1, the other has a depth of d2, and d1-d2 is approximately λ / 2 (n -1) A method of manufacturing a phase shift mask in which a substrate-engraving type phase shift mask provided with an adjacent light-transmitting portion is provided. A first engraving step of selectively dry-etching the transparent substrate portion to a predetermined depth D1 with respect to the light-transmitting portion having a depth of d1; The optical part is further wet-etched to obtain λ / 2 (n
A second engraving process, engraving to the depth of -1)
(C) performing a third engraving step of performing wet etching on the entire light transmitting portion. In the above, the substrate-engraving type phase shift mask is a Levenson type phase shift mask. Further, in the above, the phase shift mask of the substrate engraving type has the exposure light having a wavelength of 24.
It is a phase shift mask for an 8 nm KrF excimer laser. Alternatively, in the above, the substrate-carved type phase shift mask is characterized in that the exposure light is a phase shift mask for an ArF excimer laser having a wavelength of 193 nm. Alternatively, in the above, the substrate-carved type phase shift mask is a phase shift mask for an F2 excimer laser whose exposure light has a wavelength of 157 nm. In the above, the engraving amount in the third engraving step is not less than 10 nm and not more than 50 nm. In the above, if δ is [λ / 2 (n-1)] / 9, d1-d2 is
[Λ / 2 (n-1)] + δ to [λ / 2 (n-1)]-δ
In the range.

The phase shift mask of the present invention has a pattern in which a light-shielding portion for shielding exposure light and a light-transmitting portion are formed on a transparent substrate having a refractive index n transparent to exposure light of wavelength λ. In addition, by engraving the transparent substrate portion of the light transmitting portion, one of the concave portions has a depth of d1, the other has a depth of d2, and d1-d2.
Λ / 2 (n-1), a substrate-carved type phase shift mask provided with an adjacent light-transmitting portion, wherein the light-transmitting portion has a depth d1 and a depth d2. In the concave portion of the light transmitting portion provided with, a concave portion following the light shielding portion side is formed by wet etching with a different side etching amount, and a different length is provided on the light transmitting portion side of the light shielding portion. It is characterized by forming an eaves of the sea. Further, in the above, it is a Levenson type phase shift mask. Further, in the above description, the exposure light has a wavelength of 248 nm.
It is a phase shift mask for an rF excimer laser. Alternatively, in the above, the exposure light is a phase shift mask for an ArF excimer laser having a wavelength of 193 nm. Alternatively, in the above, the exposure light is a phase shift mask for an F2 excimer laser having a wavelength of 157 nm. In the above, the depth d
The difference between the length of the eaves on the side of the light-transmitting portion where the concave portion of 1 is provided and the length of the eaves on the side of the light-transmitting portion where the concave portion of depth d2 is provided is larger than 0 and 2
The thickness is not more than 00 nm.

[0008]

The method of manufacturing a phase shift mask according to the present invention can solve the problem of the dimensional difference of the resist on the wafer corresponding to the engraved portion and the non-engraved portion by adopting such a configuration. It is possible to provide a method of manufacturing an engraved phase shift mask for manufacturing an engraved phase shift mask having a practical structure in terms of strength.
That is, the problem of the dimensional difference between the resist images on the wafer corresponding to the engraved portion and the non-engraved portion of the single-engraved type phase shift mask shown in FIG. 4C, and the double engraved type shown in FIG. In order to sufficiently obtain the dimension correction effect of the phase shift mask, the engraving type phase shift mask that can solve the problem that both sides are largely etched and peeling and chipping cannot be avoided is produced. It is possible to provide a method for manufacturing a phase shift mask. Specifically, on a transparent substrate having a refractive index n transparent to exposure light having a wavelength λ, a pattern in which a light-shielding portion for shielding exposure light and a light-transmitting portion are formed, and A substrate provided with an adjacent light-transmitting portion in which one of the concave portions has a depth of d1 and the other concave portion has a depth of d2, and d1-d2 is approximately λ / 2 (n-1). A method of manufacturing a phase shift mask for manufacturing an engraved phase shift mask, comprising: (a) forming a light-shielding portion, and then forming a transparent substrate portion on a light-transmitting portion having a recess depth of d1. A first engraving step of selectively engraving a predetermined depth D1 by dry etching, and (b) further wet-etching the light-transmitting portion having the depth of the concave portion d1 by λ / 2 ( n
A second engraving process, engraving to the depth of -1)
(C) This is achieved by performing a third engraving step of performing wet etching on the entire light transmitting portion. That is, by performing the first engraving step and the second engraving step, the position of the exposure light between the translucent portion having the depth of the recess d1 and the translucent portion having the depth of the recess d2 is obtained. By obtaining a conventional single-carved substrate engraving type phase shift mask shown in FIG. 4C with a phase difference of approximately a predetermined value π (180 °), a third engraving step is performed.
The depth of the concave portion of the light-shielding film 320 is set to d, as in a conventional double-carved type substrate-carved type phase shift mask shown in FIG.
The sum of the side etch amounts (also referred to as the lengths of the eaves) Wb1 and Wb2 (Wb
In other words, the eaves portion 325 is less likely to be peeled or chipped, and in the single-sided type substrate engraving phase shift mask shown in FIG.
The problem of the dimensional difference between the resist images on the wafer corresponding to the engraved portion and the non-engraved portion is solved.

An applicable phase shift mask of the substrate engraving type is a Levenson type phase shift mask, which is particularly effective when applied to an obliquely arranged hole pattern of 1.0 μm or less. .

Further, the substrate-engraving type phase shift mask is effective when the exposure light is a phase shift mask for a KrF excimer laser having a wavelength of 248 nm. It is more effective when the phase shift mask is for an ArF excimer laser, and is particularly effective when the substrate-carved type phase shift mask is a phase shift mask for an F2 excimer laser having a wavelength of 157 nm. .

As the engraving amount D1 in the first engraving step, the side etching amount by wet etching in the second and third engraving steps is made as small as possible, and from the viewpoint of light intensity adjustment, 50 to 70 °. The amount that causes the phase shift is preferably equal to or more than the amount that causes the phase shift. In this case, from the aspect of light intensity adjustment (correction), the engraving amount in the third engraving step needs to be 10 nm or more. Engraving amount,
The thickness is set to 50 nm or less.

Incidentally, such a light intensity adjustment (correction) is particularly performed when d is [λ / 2 (n-1)] / 9, where d1-d
2 is (2m−1) λ / 2 (n−1) + δ to (2m−
1) It is effective when it is in the range of λ / 2 (n-1) -δ. Here, m is a natural number.

The phase shift mask of the present invention can solve the problem of the dimensional difference of the resist on the wafer corresponding to the engraved portion and the non-engraved portion by adopting such a configuration, and can improve the strength. This also makes it possible to provide a practically structured substrate-carved type phase shift mask.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a process sectional view of a characteristic portion of one example of an embodiment of a method for manufacturing a phase shift mask of the present invention.
FIG. 2E is a cross-sectional view of a characteristic portion of an example of the embodiment of the phase shift mask of the present invention. FIG. 2A shows a case where the structure of the phase shift mask of the present invention is applied to a hole pattern and projected. FIG. 2B is a diagram showing the light intensity distribution of adjacent light transmitting portions (hole portions) on the wafer, FIG. 2B is a diagram showing an arrangement of hole patterns, and FIG. FIG. 3B shows a light intensity distribution on a wafer of an adjacent light transmitting portion (hole portion) when the structure of the phase shift mask of the type is applied to the hole pattern and projected. 4A is a cross-sectional view of a shifter forming type phase shift mask, and FIGS. 4B to 4D illustrate a conventional engraving type phase shift mask. FIG. 4 is a cross-sectional view of a characteristic part for performing the above. 1 to 3, 110 is a substrate (also called a transparent substrate), 120 is a light-shielding film, 120A is a light-shielding portion, 125 is an eave, 130, 131, 132, and 135 are engraved portions (both dug portions or simply concave portions). Say) 1
50 is a light transmitting portion (hole portion) having a depth d1 of the concave portion, 150
A, 150B are the light intensity on the wafer, 151 is the resist image,
160 is a light transmitting portion (hole portion) having a depth d2 of the concave portion, 160
A, 160B are the light intensity on the wafer, 161 is the resist image,
170 is a light transmitting portion, 175 is a pitch between adjacent holes of the mask, 175A is a pitch between holes of a projected image, 180 is a light shielding portion (light shielding film), 190 and 191 are light intensity profiles (on a wafer), 195, 196 is a threshold value.

An example of an embodiment of a method for manufacturing a phase shift mask according to the present invention will be described with reference to the drawings. This example has a method of manufacturing a phase shift mask having a hole pattern (light-transmitting portion 170) having an arrangement as shown in FIG. The light-transmitting portion 170 of the transparent substrate having a refractive index of n, which is transparent to light, is engraved on the transparent substrate portion exposed from the light-shielding film, and the depth of one concave portion of the adjacent light-transmitting portion (hole pattern) 170 is set to d1,
The depth of the other recess is d2, and d1-d2 is approximately λ / 2.
(N-1) A method for manufacturing a substrate-carved type phase shift mask.

First, a mask blank in which a light-shielding film 120 is provided on one surface of a transparent substrate 110 having a refractive index of n which is transparent to exposure light having a wavelength λ is prepared (FIG. 1A). A resist film (not shown) having a predetermined opening according to the shape of the light shielding portion to be formed.
Is formed, and the resist film is used as an etching resistant mask.
By performing dry etching or the like, a light shielding portion 120A of a predetermined shape made of the light shielding film 120 is formed. After that, the light shielding unit 12
The resist film for forming 0A is removed, and a cleaning process is performed. (FIG. 1B) When chromium or chromium oxynitride is used for the light-shielding film 120, a chlorine-based gas is used as an etchant.
Perform dry etching. The resist is not particularly limited as long as it has good processing properties, has a predetermined resolution, and has etching resistance.

Next, the surface on the side on which the light-shielding film 120 is formed is covered with a resist film (not shown) having an opening in a light-transmitting portion having a depth of d1, and the depth of the recess is adjusted. d
1 is selectively etched by dry-etching at a light-transmitting portion to make a predetermined depth D1. The engraving depth is controlled by a phase difference measuring device (Lasertec MPM-24).
8) and the like can be performed accurately. in this case,
Dry etching is anisotropic, and engraving (etching) proceeds only in a direction substantially perpendicular to the transparent substrate surface. The transparent substrate exposed from the opening is dry-etched using a fluorine-based gas as an etchant. Thereafter, the resist film for dry etching is removed, and a cleaning process is performed.
(FIG. 1 (c)) The resist is not particularly limited as long as it has good processability, has a predetermined resolution, and has dry etching resistance.

Next, the surface on the side on which the light-shielding film 120 is formed is covered with a resist film (not shown) having an opening in a light-transmitting portion having a depth of d1, and the depth of the recess is adjusted. d
1 is selectively wet-etched at the light-transmitting portion to be carved to a depth (d0) of approximately λ / 2 (n-1). Next, a resist film (not shown) covering the surface on the side where the light-shielding film 120 is formed and opening the light-transmitting portion where the depth of the concave portion is d1 is removed, and a cleaning process is performed.
(FIG. 1D) In this case, the wet etching is isotropic, and the engraving (etching) proceeds at substantially the same speed in each direction. A hydrofluoric acid solution is used as an etchant for wet etching. The resist is not particularly limited as long as it has good processability, has a predetermined resolution, and has resistance to wet etching. This step is shown in FIG.
This corresponds to the conventional single-sink type phase shift mask shown in FIG.

Thereafter, wet etching is performed on the entire light-transmitting portion on the surface on which the light-shielding film 120 is formed, and the light-transmitting portion 150 having one adjacent hole pattern portion with the depth of the recess d1 and the other light-transmitting portion 150 is formed. The light-transmitting portion 160 with the depth of the concave portion d2 is obtained. (FIG. 1 (e)) In this way, a hole pattern (light-transmitting portion 170) having an arrangement as shown in FIG.
Can be obtained.

Next, an embodiment of the phase shift mask according to the present invention will be described. FIG. 1E shows a cross section of this example manufactured by the manufacturing method shown in FIG.
The hole pattern (light-transmitting portion) 170 having the arrangement shown in FIG. 2B is engraved on the transparent substrate portion of the hole pattern (light-transmitting portion) 170, and the depth of one concave portion is set to d1, and the other concave portion is set to d1. d2, and d1−d2 is approximately λ / 2 (n−1).
Adjacent light-transmitting portions are provided. And the depth d1
Hole pattern (light-transmitting part) 150 for providing a concave part, hole pattern (light-transmitting part) for providing a concave part of depth d2
In the concave portion of 160, a concave portion following the light shielding portion side is respectively provided.
Eaves 125 are formed by wet etching with different side etching amounts W2 and W3, and different lengths of eaves 125 are formed on the light transmitting portion side of the light shielding portion 120A.
As the transparent substrate 110, synthetic quartz is generally used. Chromium or chromium oxynitride is used for the light-shielding film 120.

When the phase shift mask of this embodiment is used, a hole pattern (light-transmitting portion) 150 of the arrangement shown in FIG.
With respect to the hole pattern (light-transmitting portion) 160, when projected, the light intensity profile 190 on the wafer is:
As shown in FIG. 2A, the widths are substantially equal, show the same width at a predetermined threshold 195, and the resist image on the wafer is formed with the same size. The light intensity on the wafer can be measured using a simulator MSM100 manufactured by Lasertec Corporation.
In the case of the state shown in FIG. 1D (corresponding to the half-carved type phase shift mask in FIG. 4C), as shown in FIG. The light intensity is different on the wafer when engraving is different from that without engraving, as shown in FIG.
FIG. 3B shows a resist image (projection image) on the wafer having the arrangement shown in FIG. That is, it can be said that the phase shift mask of the present example is a mask obtained by correcting the light intensity on the wafer with respect to the half-carved type phase shift mask of FIG. Further, the difference between the length of the eaves on the light-transmitting portion side where the concave portion with the depth d1 is provided and the length of the eaves on the light-transmitting portion side where the concave portion with the depth d2 is set to be larger than 0 and 200 nm or less. Wet etching can be performed so that the transmission intensity is equal without causing peeling or chipping of the portion.

[0022]

EXAMPLES The present invention will be further described with reference to examples.
In the example, a Levenson-type phase shift mask for KrF having the hole pattern arrangement shown in FIG. 2B is formed by the cross section shown in FIG. 1E by the manufacturing method shown in FIG. is there. First, a light-shielding film in which a chromium film (110 nm thick) and chromium oxide (several nm thick) are sequentially stacked on one surface of a transparent substrate 110 made of a synthetic quartz substrate (hereinafter also referred to as a Qz substrate) as shown in FIG. A photomask blank provided with the photomask blank 120 is prepared (FIG. 1A), and a resist ZEP is formed on the light shielding film 120 of the photomask blank.
(Manufactured by Zeon Co., Ltd.) and the EB drawing apparatus HL
800 (manufactured by Hitachi, Ltd.), developed with an inorganic alkali developing solution, and chromium oxide and chromium in the opening were dry-etched with an etchant containing chlorine as a main component, and the resist was peeled off and washed. (FIG. 1 (b)) Incidentally, a hole pattern (light-transmitting portion) 1 where the depth of the concave portion is d1.
The opening size of the 50 light shielding films 120 is set to 0.6 μm square,
Hole pattern (light-transmitting portion) 160 having a recess depth of d2
The opening size of the light shielding film 120 was set to 0.6 μm □, and the pitch was set to 1.2 μm.

Next, the surface on the side where the light-shielding film 120 is formed is covered with a resist film (not shown) having an opening in a light-transmitting portion with a depth of d1, and the depth of the recess is adjusted. d
Then, the light-transmitting portion 1 is selectively dry-etched using CF ₄ gas, and is carved to a predetermined depth of 75 nm (a depth that causes a phase difference of 54 ° in the transparent substrate 110). The resist was stripped and washed. (FIG. 1C) As a resist film for selectively performing the dry etching, a new resist IP3500 (manufactured by Tokyo Ohka Kogyo Co., Ltd.) is applied on the surface on the side where the light shielding film 120 is formed. Laser drawing equipment (ALEC300 manufactured by ETEC)
0), and formed by developing with an inorganic alkali developer. Phase difference measuring device (MPM-24 manufactured by Lasertec)
Using 8), dry etching was stopped at a depth (about 75 nm) at which a phase difference of 54 ° was generated in the transparent substrate 110 while accurately measuring the engraving amount by etching.

Next, a resist IP3500 is used to wet-etch the engraved depth of the light-transmitting portion where the depth of the concave portion is d1 to a depth (about 245 nm) that causes a 180 ° phase difference in the transparent substrate 110. Is newly applied, drawn with a laser drawing device, developed with an inorganic alkali developer, and formed a resist film having an opening only in a light-transmitting portion where the depth of the recess is d1, and then using hydrofluoric acid, Wet etching was performed to match the depth (about 245 nm) at which a phase difference of 180 ° is generated in the transparent substrate 110.
Then, the resist was stripped and washed. (FIG. 1D) At this time, the side etching amount W1 was 170 nm.

Next, side etching was performed on the shifter portion and the non-shifter portion by about 30 nm by wet etching the entire surface using hydrofluoric acid. (FIG. 1E) The etching amount was adjusted to a desired value using a stylus-type step difference measuring instrument or an atomic force microscope. The side etching amount W2 is 200 nm, and the side etching amount W3 is 30
nm.

(Comparative Example) A comparative example shows a cross section shown in FIG. 1D by the manufacturing method shown in FIG. 1 and has a hole pattern arrangement shown in FIG. Although the phase shift mask is formed and the process contents up to FIG. 1D are almost the same as those of the manufacturing method of the first embodiment, the engraving of the light-transmitting portion where the depth of the recess is d1 is performed by dry engraving. Etching is performed to a depth (about 45 nm) at which a phase difference of 32 ° is generated in the transparent substrate 110, and wet etching is performed to a depth (about 245n) at which a phase difference of 180 ° is generated.
m), and the engraving has been completed. FIG. 1D corresponds to the single engraving type phase shift mask shown in FIG. 4C. In the case of the mask shown in FIG. 1D of the comparative example, the side etching amount (FIG. 1D) is obtained by engraving a depth (about 245 nm) that causes a 180 ° phase difference by wet etching after dry etching. W1) was 200 nm.

The side etching amount W2 of the phase shift mask of the example and the side etching amount W1 of the phase shift mask of the comparative example are both 200 nm. However, in the example and the comparative example, the side etching amount shown in FIG. The light intensity of the hole pattern portions (light transmitting portions) 150 and 160 on the wafer was examined. In the case of the phase shift mask of the embodiment, the light intensity profile on the wafer is as shown in FIG. 2A, and the light intensity of the adjacent hole pattern corresponding to the hole pattern portions (light transmitting portions) 150 and 160, respectively. There was almost no difference between the profiles 150A and 160A. On the other hand, in the case of the phase shift mask of the comparative example, the difference between the hole pattern (light-transmitting portion) 150, the hole pattern (light-transmitting portion) 160, and the light intensity profile on each wafer is slightly larger than that of the embodiment. Was seen. The light intensity on the wafer was measured by Laser Tech simulator MSM.
100 was measured. This is because the phase shift mask of the embodiment has a smaller side etching amount (FIG. 1).
(E) The length 125 of the eaves is not larger than the side etching amount of the phase shift mask of the comparative example, and FIG.
In the stage (d), when the processing is completed at (W1 is 170 nm), the light intensity profile on the wafer of the mask can be obtained by correcting the light intensity profile on the wafer. Means. Incidentally, FIG. 1D in the middle of manufacturing the phase shift mask of the embodiment.
In this stage, W1 is 170 nm, and the mask when the processing is terminated at this point is adjacent to the hole pattern portions (light transmitting portions) 150 and 160, respectively, as shown in FIG. The light intensity profiles 150B and 160B of the hole pattern seemed clear and could not be used at a practical level.

[0028]

As described above, the present invention can solve the problem of the dimensional difference of the resist on the wafer corresponding to the engraved portion and the non-engraved portion, respectively, and has a practical structure in terms of strength. It has become possible to provide an engraved phase shift mask. At the same time, it has become possible to provide a method for manufacturing such a substrate-engraving type phase shift mask.

[Brief description of the drawings]

FIG. 1A is a process sectional view of a characteristic portion of an example of an embodiment of a method for manufacturing a phase shift mask of the present invention.
(E) is a sectional view of a characteristic portion of an example of the embodiment of the phase shift mask of the present invention.

FIG. 2A shows a light intensity distribution on a wafer of an adjacent translucent portion (hole portion) when the structure of the phase shift mask of the present invention is applied to a hole pattern and projected. FIG. 2B is a diagram showing an arrangement of hole patterns.

FIG. 3 (a) shows a light intensity distribution on a wafer of an adjacent light transmitting portion (hole portion) when the structure of a conventional single engraving type phase shift mask is applied to a hole pattern and projected. FIG. 3B shows the state of the resist image in that case.

FIG. 4A is a cross-sectional view of a shifter forming type phase shift mask, and FIGS. 4B to 4D are characteristic portions for explaining a conventional engraving type phase shift mask. It is sectional drawing.

[Explanation of symbols]

Reference Signs List 110 substrate (also called transparent substrate) 120 light-shielding film 120A light-shielding part 125 eaves 130, 131, 132, 135 carved part (also called engraved part or simply concave part) 150 light-transmitting part (hole part) with depth d1 of concave part 150A, 150B Light intensity on wafer 151 Resist image 160 Light transmitting portion (hole) with depth d2 of concave portion 160A, 160B Light intensity on wafer 161 Resist image 170 Light transmitting portion 175 Pitch between adjacent holes of mask 175A (projected image) ) Hole pitch 180 light-shielding portion (light-shielding film) 190, 191 light intensity profile 195, 196 threshold value 310 transparent substrate 320 light-shielding film 321 opening (light-transmitting portion) 322, 322A opening (light-transmitting portion) 323, 323A opening Portion (light-transmitting portion) 324, 324A Opening portion (light-transmitting portion) 325 Eave 330 Shift Data 340, 345, 347 Carved portion (also referred to as concave portion) Wa, Wb1, Wb2 Side etching amount

Claims (13)

[Claims] 1. A refractive index n transparent to exposure light having a wavelength λ.
On the transparent substrate, a pattern in which a light-shielding portion for shielding exposure light and a light-transmitting portion are formed, and the transparent substrate portion of the light-transmitting portion is engraved, and the depth of one recess is d1, and the other is d1. The depth of the concave portion is d2, and d1-d2 is substantially λ / 2 (n-1).
A phase shift mask manufacturing method for manufacturing a substrate-engraving type phase shift mask provided with an adjacent light-transmitting portion, in which (a) after forming a light shielding portion, the depth of the concave portion is set to d.
A first engraving step of selectively dry-etching the transparent substrate portion to a predetermined depth D1 for the light-transmitting portion 1; and (b) a light-transmitting portion having a recess depth d1. Part is further wet-etched to obtain λ / 2 (n−
A second engraving step of engraving at the depth of 1), (c)
A method of manufacturing a phase shift mask, comprising performing a third engraving step of performing wet etching on all light transmitting portions. 2. The method of manufacturing a phase shift mask according to claim 1, wherein the substrate-engraving type phase shift mask is a Levenson type phase shift mask. 3. The method for manufacturing a phase shift mask according to claim 1, wherein the substrate-carved type phase shift mask is a phase shift mask for a KrF excimer laser having a wavelength of 248 nm for exposure light. 4. The method for manufacturing a phase shift mask according to claim 1, wherein the phase shift mask of the substrate engraving type is a phase shift mask for an ArF excimer laser whose exposure light has a wavelength of 193 nm. 5. The method for manufacturing a phase shift mask according to claim 1, wherein the phase shift mask of the substrate engraving type is a phase shift mask for an F2 excimer laser having a wavelength of 157 nm for exposure light. 6. The engraving amount according to claim 1, wherein the engraving amount in the third engraving step is 10 nm or more and 50 n or more.
m or less. 7. The method according to claim 1, wherein δ is [λ /
2 (n-1)] / 9, d1-d2 is [λ / 2
(N-1)] + δ to [λ / 2 (n-1)]-δ. 8. A refractive index n transparent to exposure light having a wavelength λ.
On the transparent substrate, a pattern in which a light-shielding portion for shielding exposure light and a light-transmitting portion are formed, and the transparent substrate portion of the light-transmitting portion is engraved, and the depth of one recess is d1, and the other is d1. The depth of the concave portion is d2, and d1-d2 is substantially λ / 2 (n-1).
A substrate-carved type phase shift mask having an adjacent light-transmitting portion, wherein a light-transmitting portion has a concave portion having a depth d1 and a light-transmitting portion has a concave portion having a depth d2. The concave portions following the sides are formed by wet etching with different side etching amounts, and the eaves of different lengths are formed on the light-transmitting portion side of the light-shielding portion, respectively. Phase shift mask. 9. The phase shift mask according to claim 8, wherein the phase shift mask is a Levenson type phase shift mask. 10. The phase shift mask according to claim 8, wherein the exposure light is a phase shift mask for a KrF excimer laser having a wavelength of 248 nm. 11. The phase shift mask according to claim 8, wherein the exposure light is a phase shift mask for an ArF excimer laser having a wavelength of 193 nm. 12. The phase shift mask according to claim 8, wherein the exposure light is a phase shift mask for an F2 excimer laser having a wavelength of 157 nm. 13. The method according to claim 8, wherein the depth d is
The difference between the length of the eaves on the side of the light-transmitting portion where the concave portion of 1 is provided and the length of the eaves on the side of the light-transmitting portion where the concave portion of depth d2 is provided is larger than 0 and 2
A phase shift mask having a thickness of not more than 00 nm.