JP2002258457A - Method for manufacturing phase shift mask and phase shift mask - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a substrate engraved phase shift mask and a method for manufacturing the mask in which a shifter part and a non-shifter part are adjacent to each other and a light shielding layer pattern made of a light shielding film is formed, the film continuously covering from the end of the shifter part to the end of the non-shifter part including the side faces of the engraved part to form the shifter part. SOLUTION: The method includes the following processes. They are (a) a metal film pattern forming process to open a region to form a graved part to form a shifter part on one surface of a transparent substrate for exposure light, (b) a dry etching process to apply a resist on the metal film pattern if necessary and to engrave the substrate to a specified amount by dry etching, (c) a process to remove the metal film pattern and to wet etch the whole surface of the substrate in the side where the engraving part is to be formed, and (d) a light shielding film pattern forming process to form a light-shielding film and to open the shifter part and the non-shifter part by a photoetching method.

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 phase shift mask of a substrate digging type 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, one method for improving the resolution of a projection exposure apparatus is to use two adjacent transparent portions on a mask. A phase shift method has been adopted in which the phases of light passing through the light are changed to increase the pattern resolution. In this method, as a shifter for inverting the phase of one of the adjacent light-transmitting portions, when the film thickness is d, the refractive index is n, and the exposure wavelength is λ, d = λ / 2 (n−
The 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 1), and the light passing through the shifter is opposite to the transmitted light of another adjacent light transmitting portion. Because of the phase (shift of 180 degrees), the light intensity becomes 0 at the pattern boundary, the pattern is separated, and the resolution is improved.

[0003] As shown in FIG. 4A, a mask shape for realizing high resolution by the above-mentioned phase shift method is such that a transparent material having a refractive index different from that of air is provided in one of adjacent openings (light transmitting portions) 521. (Also called phase shift film or shifter)
Although there is a shifter forming type phase shift mask provided with a phase shifter 530, it is difficult to accurately deposit a phase shift film having the same refractive index as that of the substrate. There is a problem. As a phase shift mask that solves these problems,
There are various types of substrate digging type phase shift masks (also referred to as engraving type phase shift masks) in which a transparent substrate is digged by etching or the like.
The substrate digging type phase shift mask shown in (c) is currently the mainstream. The digging type phase shift mask shown in FIGS. 4B and 2B performs dry etching of the substrate (in general, Qz is used) halfway, as shown in FIGS. This is called a one-side digging type phase shift mask in which wet etching is added only to the digging part to generate a predetermined phase difference (usually 180 °), and the digging type phase shift mask shown in FIG. As shown in FIG. 4B and FIG. 4B, a double-dug type phase-change substrate is obtained by dry-etching the substrate so as to generate a predetermined phase difference (usually 180 °), and further adding wet etching to the entire opening. This is called a shift mask. In a substrate digging type phase shift mask in which the substrate is simply dry-etched vertically (a predetermined phase difference (usually 180 °) in FIG. 4 (b) (a)), the presence or absence of the substrate digging in the opening is determined. There is a problem that the transmitted light intensity is different. In order to solve this problem, FIGS.
The substrate digging type phase shift mask shown in (c) has been developed. In general, a transparent substrate having a refractive index n transparent to exposure light having a wavelength λ has a pattern in which a light-shielding portion for shielding exposure light and a light-transmitting portion are formed. When the transparent substrate is dug, the depth of one recess is d1, the depth of the other is d2, and d1-d2 is approximately λ / 2 (n
-1) The phase shift mask provided with the adjacent light-transmitting portion is referred to as a digging type phase shift mask.
A case where one of d1 and d2 is 0 is a single-dig type phase shift mask, and a case where both d1 and d2 are not 0 is a double-dig type phase shift mask. In general, a concave portion having a large concave depth (also referred to as a dug amount) d1, d2 is referred to as a shifter portion, and a small concave portion is referred to as a non-shifter portion.

However, in the structure of the digging type phase shift mask shown in FIGS. 4B and 2C and FIG. 4C, an eave 525 of the light-shielding film is formed by wet etching, so that the light-shielding film may be chipped. Peeling is likely to occur. In particular, the cleaning resistance after wet etching is significantly reduced, and normal cleaning cannot be performed. Also, as circuit patterns become finer in the future as semiconductor integrated circuits operate at higher speeds and higher densities, the light-shielding film peels off during wet etching with this structure, making it difficult to manufacture. In recent years, in order to solve this structural problem, an etched part (shifter part) and a non-etched part (non-shifter part) have been dug with a substrate digging type phase shift mask.
A substrate digging type phase shift mask having a structure as shown in FIG. 5 in which a light-shielding film is formed so as to continuously cover from an end of the shifter portion to an end of a part of the non-shifter has been proposed. With the mask having the structure shown in FIG. 5, since there is no eave of the light-shielding film, chipping or peeling does not occur, and a mask having excellent durability can be manufactured. However, when fabricating a substrate digging type phase shift mask having a structure as shown in FIG.
It is necessary to uniformly form the light-shielding film even on the step portion of the substrate. If the light-shielding film is formed non-uniformly, various problems occur, such as an influence on the processing accuracy at the time of plate making and a decrease in cleaning resistance in a thin portion of the light-shielding film.

[0005]

As described above, the etched portion (shifter portion) and the non-etched portion (non-shifter portion)
Is a side-digging type substrate digging type phase shift mask adjacent to each other, and a light-shielding film is formed so as to cover an end of a shifter part and a part of a non-shifter, as shown in FIG. There has been a demand for a phase shift mask having a structure and capable of uniformly forming a light-shielding film even on a step portion of a substrate, and a method of manufacturing the same. The present invention corresponds to this, the shifter portion and the non-shifter portion are adjacent to each other, and from the end of the shifter portion to the end of the non-shifter part,
A side-digging type substrate-digging type phase shift mask in which a light-shielding layer pattern made of a light-shielding film continuously covered is formed, including side surfaces of a dug portion (also referred to as a concave portion) for forming a shifter portion. An object of the present invention is to provide a phase shift mask capable of uniformly forming a light shielding film even on a step portion of a substrate, and a method of manufacturing the same.

[0006]

According to a method of manufacturing a phase shift mask of the present invention, a shifter portion and a non-shifter portion are adjacent to each other, and a shifter portion is formed from an end of the shifter portion to an end of a portion of the non-shifter. A phase shift mask for manufacturing a single-sided type substrate dug-in type phase shift mask in which a light-shielding layer pattern made of a light-shielding film is continuously covered, including a side surface portion of a dug-out portion (recess) to be formed. A method of manufacturing a shift mask, comprising the steps of: (a) opening a dug portion forming region for forming a shifter portion on one surface of a substrate which is transparent to exposure light and has a flat surface on both sides; A metal film pattern forming step of forming a pattern, and (b) providing a resist on the metal film pattern as necessary, digging the substrate by dry etching, setting the wavelength of the exposure light to λ, and the refractive index of the substrate. And n Approximately λ / 2 (n-1) narrowing portion depth d0 of (recess) digging, and dry etching process,
(C) a wet etching step of removing the metal film pattern and performing wet etching on the entire surface of the substrate where the digging portion is formed; and (d) a side surface portion of the digging portion (recess) for forming the shifter portion. A light-shielding film pattern forming step of forming a light-shielding film that continuously covers the entire surface of the substrate where the digging portion is formed, and forming a light-shielding film pattern including a light-shielding film that opens a shifter portion and a non-shifter portion by a photoetching method; And characterized in that: And in the above, the wet etching step is performed in a range of 10 nm to 100 nm.
nm etching. Further, in the above, the wet etching step is characterized by performing etching with hydrofluoric acid. Alternatively, in the above, the wet etching step is characterized in that wet etching is performed with hot alkali.

In the phase shift mask according to the present invention, the shifter portion and the non-shifter portion are adjacent to each other, and a dug portion (recessed portion) for forming the shifter portion extends from an end of the shifter portion to an end of a portion of the non-shifter. ) Is a one-side digging type substrate dug-in type phase shift mask in which a light-shielding layer pattern made of a light-shielding film is continuously covered, including a side surface portion, which is formed by the photomask manufacturing method of the present invention. It is characterized by having been done.

Here, a transparent substrate having a refractive index n transparent to exposure light having a wavelength λ has a pattern in which a light-shielding portion for shielding the exposure light and a light-transmitting portion are formed. And the depth of one recess is d1, and the depth of the other recess is d2, and d1-d2 is approximately λ / 2 (n-1).
The phase shift mask provided with the adjacent light-transmitting portions is referred to as a substrate digging type phase shift mask, and a case where one of d1 and d2 is 0 is particularly referred to as a single digging type substrate digging type phase shift mask. To tell. Further, here, the concave side with the larger concave depths (also referred to as digging amounts) d1 and d2 is called a shifter portion, and the smaller concave side is called a non-shifter portion.

The phase shift mask of the present invention can be a Levenson type phase shift mask. The exposure light has a wavelength of 248 nm.
The present invention can also be applied to a phase shift mask for an rF excimer laser, a phase shift mask for an ArF excimer laser whose exposure light has a wavelength of 193 nm, and a phase shift mask for an F2 excimer laser whose exposure light has a wavelength of 157 nm.

[0010]

According to the method of manufacturing a phase shift mask of the present invention, by adopting such a structure, the shifter portion and the non-shifter portion are adjacent to each other, and from the end of the shifter portion to the end of the non-shifter part. Digging type phase shift mask in which a light-shielding layer pattern made of a light-shielding film is continuously covered, including a side surface of a dug portion (also referred to as a concave portion) for forming a shifter portion. Accordingly, it is possible to provide a method of manufacturing a phase shift mask that can uniformly form a light shielding film even on a step portion of a substrate. After performing the dry etching process, peel off the metal film on the entire surface,
Thereafter, by performing a wet etching step of performing wet etching on the entire surface of the substrate where the digging portion is formed, a uniform light shielding layer is also formed on the step portion of the substrate when a light shielding film is formed on the entire surface of the substrate. It is possible to form a film. Thereby, as in the case of the conventional structure of FIG.
A phase shift mask can be formed without uneven formation of the light shielding film. As a substrate-engraving type phase shift mask that can be applied, a Levenson type phase shift mask is mentioned, and a wet etching process is performed in a range of 10 nm to 100 nm.
This is particularly effective when etching is performed.

[0011] Further, a single-cut type 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,
Exposure light is wavelength 1
It is also effective when a phase shift mask for a 93 nm ArF excimer laser or an exposure light is a phase shift mask for an F2 excimer laser having a wavelength of 157 nm.

In the phase shift mask of the present invention, by adopting such a configuration, the shifter portion and the non-shifter portion are adjacent to each other, and the shifter portion and the non-shifter portion have a shifter portion. A digging-type substrate digging-type phase shift mask in which a light-shielding layer pattern made of a light-shielding film that covers continuously, including a side surface of a digging portion (also referred to as a concave portion) for forming a portion, is formed. It is possible to provide a phase shift mask capable of uniformly forming a light shielding film even on a stepped portion.

[0013]

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.
(I) is a cross-sectional view of a characteristic portion of one example of the embodiment of the phase shift mask of the present invention, FIG. 2 is a process diagram of a comparative example, and FIG.
(A) is a diagram showing a light intensity distribution on a wafer of an adjacent light transmitting portion (line portion) when the structure of the phase shift mask of the present invention is applied to a line and space pattern and projected. FIG. 3B is a diagram showing an arrangement of line and space patterns. 1 to 3, reference numeral 110 denotes a substrate (also referred to as a transparent substrate), 115 denotes a dug portion (also referred to as a concave portion), 116 denotes a side portion, 117 and 117a denote a top portion, 1
18, 118a are bottom corners, 120 is a metal film, 120A metal film pattern, 125 is an opening, 130 is a dry etching gas, 135 is a resist film, 140 is a light shielding film, 14
0A is a light shielding film pattern, 145 is an opening, 150 is a shifter part (light transmitting part), 155 is a non-shifter part (light transmitting part), 25
0 is a light transmitting portion (also referred to as a line portion or a line pattern portion) having a depth d1 = 0 of the concave portion, and 250A is the light intensity on the wafer, 2
Reference numeral 60 denotes a light transmitting portion (also referred to as a line portion or a line pattern portion) having a depth d2 of the concave portion;
0 is a light transmitting portion (also called a line portion or a line pattern portion), 275 is a pitch between adjacent lines of the mask, 27
5A is a pitch between lines of a projected image, 280 is a light-shielding portion (light-shielding film), 290 is a light intensity profile (on a wafer), 2
95 is a threshold value.

One embodiment of a method for manufacturing a phase shift mask according to the present invention will be described with reference to FIG. In this example, the shifter portion and the non-shifter portion are adjacent to each other, and from the end of the shifter portion to the end of the non-shifter part, including the side surface of the dug portion (recess) for forming the shifter portion, FIG. 3 shows a method for manufacturing a phase shift mask for manufacturing a single-cavity type substrate digging type phase shift mask in which a light shielding layer pattern made of a light shielding film continuously covered is formed.
Line patterns (light-transmitting portions 27) having an arrangement as shown in FIG.
0), and a transparent substrate exposed from the light-shielding film and having a refractive index of n, which is transparent to exposure light having a wavelength λ and has a cross section shown in FIG. The depth of one concave portion of the adjacent light transmitting portion 270 is d1 = 0, the depth of the other concave portion is d2, and d2 is approximately λ /.
A case of manufacturing a 2 (n-1) single-sided engraved substrate phase shift mask will be described as an example. First, a two-sided flat substrate 110 transparent to exposure light having a wavelength λ is prepared (FIG. 1A), and a metal film 120 is formed on one surface thereof. (FIG. 1B) Next, the metal film 120 is subjected to photo-etching processing, and a metal film having a dug portion forming region for forming a shifter portion is formed on one surface of the substrate 110 (also referred to as photomask blanks). 120A metal film pattern 120A
To form (FIG. 1C) After a metal film 120 is formed on the substrate 110 by a sputtering method, a vapor deposition method, or the like, a resist film having a predetermined opening is formed by an ordinary photolithography method in accordance with the shape of the metal pattern to be formed. (Not shown), and dry etching or wet etching is performed using the resist film as an etching resistant mask to form a metal film 120.
A metal film pattern 120A having a predetermined shape is formed.
Thereafter, a resist film for forming the metal film pattern 120A is
Remove and wash. Quartz or synthetic quartz is generally used as the substrate 110 that is transparent to both sides of the exposure light having the wavelength λ. When chromium or chromium oxynitride is used for the metal film 120, dry etching can be performed using a chlorine-based gas as an etchant. The resist is not particularly limited as long as it has good processing properties, has a predetermined resolution, and has etching resistance.

Next, a dry etching resistant resist film 135 is formed on the light-shielding pattern 120A by a photolithographic method, and the resist film 135 and the metal film pattern 120A are used as an etching resistant mask to dig the substrate by dry etching to expose the substrate. The wavelength of light is λ and the refractive index of the substrate is n
And the depth d0 of the dug portion (recess) is substantially λ /
2 (n-1) is performed. (FIGS. 1 (d) and 1 (e)) The engraving depth can be accurately controlled by using a phase difference measuring device (MPM-248 manufactured by Lasertec) or the like. In this case, the dry etching is anisotropic, and is engraved (etched) only in a direction substantially perpendicular to the transparent substrate surface.
Advances. The transparent substrate exposed from the opening is dry-etched using a fluorine-based gas such as CF ₄ as an etchant. The resist is not particularly limited as long as it has good processability, has a predetermined resolution, and has dry etching resistance. In some cases, FIG.
As shown in (1), the substrate may be dug by dry etching without providing a resist film on the metal film pattern 750. In FIG. 6, 710 is a substrate, 730 is a dry etching processing gas, and 750 is a metal film pattern.

Next, after dry etching, the resist film 135 is removed, and the metal film pattern 1 made of the metal film 120 is removed.
20A was peeled off and subjected to a cleaning treatment and the like (FIG. 1 (f)).
Thereafter, wet etching is performed on the entire surface of the substrate 110 on the side where the digging portion 115 is formed. (FIG. 1 (g)) In this case, wet etching is isotropic, and digging (etching) proceeds at substantially the same speed in each direction. As an etchant for wet etching, a hydrofluoric acid solution or a hot alkaline solution is used. The etching amount of the wet etching is preferably 10 nm to 100 nm.

Next, a light shielding film 140 that continuously covers the entire surface of the substrate 110 on which the digging portion 115 is formed, including the side surface of the digging portion (recess) 115 for forming the shifter portion.
(FIG. 1 (h)), and a light-shielding film 140 that opens the shifter portion and the non-shifter portion by photoetching.
Is formed. (Figure 1
(I) After forming the light-shielding film 140 on the substrate 110 by a sputtering method, an evaporation method, or the like, a resist film having a predetermined opening according to the shape of the light-shielding portion to be formed by ordinary photolithography as described above. (Not shown) is formed, and dry etching or wet etching is performed using the resist film as an etching resistant mask to form a light shielding film pattern 140A of a predetermined shape composed of the light shielding film 140. Thereafter, the resist film for forming the light shielding film pattern 140A is removed, and a cleaning process is performed. When chromium or chromium oxynitride is used for the light-blocking film 140, dry etching can be performed using a chlorine-based gas as an etchant. The resist is not particularly limited as long as it has good processing properties, has a predetermined resolution, and has etching resistance.

In this manner, the single-pit type phase shift mask shown in FIG. 1I can be manufactured. In this example, the metal film pattern 120 made of the metal film 120 is used.
After exfoliation of A (FIG. 1F), wet etching is performed, so that the top 117 and the bottom corner 118 of the side surface 116 of the dug portion 115 shown in FIG. 1 (g) top top 117a, bottom corner 11
8a, when the light shielding film 140 is formed, the light shielding film 140 can be formed uniformly as in the case of the flat portion. (FIG. 1H) For this reason, even if the light-shielding film 140 is further etched to form the light-shielding film pattern 140A and the shifter portion 150 and the non-shifter portion 155 are formed, the side surface portion 116 of the dug portion 115 is formed. No light-shielding film defects occur at the top 117a and bottom corner 118a.

Next, an embodiment of the phase shift mask according to the present invention will be described. In this example, one cross section is shown in FIG. 1 (i) manufactured by the manufacturing method shown in FIG.
The line pattern (light-transmitting portion 270) having the arrangement shown in (b) is dug in the transparent substrate portion of the line pattern (light-transmitting portion 270), and the depth of one concave portion is d1 = 0, and the other concave portion is An adjacent light-transmitting portion having a depth d2 substantially equal to λ / 2 (n-1) is provided. Here, λ is the wavelength of the exposure light, and n is the substrate 1
It has a refractive index of 10. As the substrate 110, a substrate transparent to exposure light at the time of projection exposure to the wafer is used. As the light shielding layer, a film having a light shielding property against exposure light at the time of projection exposure to the wafer is used. Usually, the substrate 110 is a quartz substrate or a synthetic quartz substrate, and the light-shielding film 140 is a chromium-based material. A single chromium layer or a chromium layer may be formed of chromium oxide, chromium nitride, Chrome and the like are laminated and used. Exposure light has a wavelength of 248 n.
m KrF excimer laser, 193 nm wavelength ArF
An excimer laser or an F2 excimer laser having a wavelength of 157 nm is used.

As a pattern of the phase shift mask, for example, a phase shift mask having a line pattern (light transmitting portion 270) arranged as shown in FIG. 3B and having a cross section shown in FIG. Is mentioned. Here, λ is the wavelength of the exposure light, n is the refractive index of the substrate, and the depth of one concave portion of the adjacent light transmitting portion (line pattern) 270 is determined by the wavelength λ of the refractive index n exposed from the light shielding film 280. The transparent substrate portion is dug into the exposure light, and is approximately λ / 2 (n−1). The depth d1 (the depth of the digging) of the concave portion of the light transmitting portion (line portion) 250 is 0, and the depth d2 of the concave portion of the light transmitting portion (line portion) 260 is approximately λ / 2 (n−1). ).

[0021]

EXAMPLES The present invention will be further described with reference to examples.
In the embodiment, the Levenson-type phase shift mask for KrF having a cross-section shown in FIG. 1I and having a line pattern arrangement shown in FIG. 3B is formed by the manufacturing method shown in FIG. is there. A description will be given based on FIGS. First,
A metal film 120 made of chromium or chromium oxide is entirely formed on one surface of a transparent substrate 110 (FIG. 1A) made of a synthetic quartz substrate (hereinafter also referred to as a Qz substrate) as shown in FIG. A resist Z is formed on the metal film 120 of the photomask blanks (FIG. 1B) formed in FIG.
After coating with EP (manufactured by Zeon Corporation), drawing with an electron beam drawing apparatus HL800 (manufactured by Hitachi, Ltd.), developing with an inorganic alkali developer, and forming a resist film (not shown) in a predetermined shape Then, the metal film 120 made of chromium oxide or chromium in the opening is dry-etched using a chlorine-based gas to remove the resist film. (Figure 1
(C))

Next, a resist IP3500 (manufactured by Tokyo Ohka Kogyo Co., Ltd.) is applied, and a laser drawing apparatus (ETE
(ALTA3000 manufactured by C Company), developed with an inorganic alkali developer, and the resist film 13 on the metal film pattern 120A.
5 is formed, dry etching is performed using CF4 gas to form a shifter portion, and the substrate 110 is dug, and the wavelength of the exposure light is λ, the refractive index of the substrate 110 is n, and the dug portion (concave portion) is formed. ) Is approximately λ / 2 (n−
1). (FIG. 1D, FIG. 1E) Next, the resist film 135 is removed, the metal film 120 is peeled off (FIG. 1F), and a 40 nm wet etching is performed on the entire surface of the substrate 110 using a hydrofluoric acid solution. Was performed. As a result, the top 117 a and the bottom corner 118 a of the dug portion 115 of the substrate are rounded. (Fig. 1 (g))

Next, a light-shielding film 140 made of chromium oxide or chromium was formed by sputtering on the entire surface of the substrate 110 on the side where the digging portion 115 was formed. (FIG. 1 (h)) Top top 117a and bottom corner 11 of the dug portion 115 of the substrate
In the state where 8a is rounded (FIG. 1 (g)), the light shielding film 140 is formed.
In the vicinity of the top 117a and the bottom corner 118a of the dug portion 115 of the substrate, as in the case of other flat portions,
A uniform film was formed.

Next, a resist ZE is formed on the light shielding film 140.
After coating with P (manufactured by Zeon Corporation), drawing with an electron beam drawing apparatus HL800 (manufactured by Hitachi, Ltd.), developing with an inorganic alkali developer, and forming a resist film (not shown) in a predetermined shape Then, the light-shielding film 140 made of chromium oxide and chromium in the opening is dry-etched using a chlorine-based gas, and further, the resist film is peeled off with a predetermined peeling liquid, and a cleaning process is performed. Of the present invention was manufactured as shown in FIG. As a result, the opening size of the light-shielding film 280 in the line pattern portion (light transmitting portion 250) of the dug portion shown in FIG. 3B is set to 0.6 μm square, and the dug is not required (the depth of the concave portion is reduced). 0) Light-shielding film 2 in line pattern portion (light-transmitting portion 260)
A phase shift mask having an opening size of 0.6 μm square and a pitch of these openings of 1.2 μm was obtained.

The projection exposure was performed on the wafer by using the obtained substrate digging type phase shift mask. After the development, the line pattern portion (light transmitting portion 250) of the digging portion of the mask was developed. A resist image and a line pattern portion (light transmitting portion 2) in which the mask is not dug (the depth of the concave portion is 0)
The resist image of 60) was formed with the same dimensions. The light intensity on the wafer was measured using a Laser Tech simulator MSM.
As a result of measurement using 100 or the like, the result was as shown in FIG. The light intensity profile 290 on the wafer is shown in FIG.
As shown in (a), the line pattern portion (light transmitting portion) 25
There was almost no difference between the light intensities 250A and 260A on the wafer of adjacent line patterns corresponding to 0 and 260, respectively.

(Comparative Example) A comparative example will be described with reference to FIG. FIG. 2C (FIG. 1)
(Equivalent to (c)). Next, resist IP35
00 (manufactured by Tokyo Ohka Kogyo Co., Ltd.), exposed with a laser drawing apparatus (ALTA3000 manufactured by ETEC), developed with an inorganic alkali developer, formed a resist film 135 on the metal film pattern 120A, and further shifted. Dry etching using CF4 gas to form a substrate 11
0, the wavelength of the exposure light is λ, and the refractive index of the substrate 110 is n, and the depth of the digging portion (recess) is substantially [λ
/ 2 (n-1)] * (65/180). (Figure 2
(D), FIG. 2 (e)) Then, in this state, wet etching is further performed with a hydrofluoric acid solution to reduce the depth of the dug portion (concave portion) to approximately [λ / 2 (n).
-1)]. (FIG. 2F) Next, the resist film 135 is removed, and the metal film 120 is removed.
Was peeled off with a predetermined liquid. (FIG. 2G) Next, after performing a cleaning process, a light-shielding film 140 made of chromium and chromium oxide was formed on the entire surface of the digging portion 115 of the substrate 110 by sputtering in the same manner as in the example. (FIG. 2 (h)) In the comparative example, the top 1 of the dug portion 115 of the substrate 110 is formed.
Since 17 is not rounded, the light shielding film 140
Was not uniformly formed. Next, as in the embodiment, photoetching is performed to form the light shielding film 1 into a predetermined shape.
40 was etched to form a shifter portion 150 and a non-shifter portion 155, thereby forming a one-sided digging type phase shift mask. In the case of the comparative example, the substrate 110
Since the top 117 of the dug portion 115 is not rounded, the formation of the light shielding film 140 at this portion becomes non-uniform,
Peeling occurred during the cleaning process.

After the state of FIG. 2G, the substrate 1
It has been confirmed that when the wet etching is performed on the entire surface of the digging portion 115 side of the light-shielding film 10, the light-shielding film 140 is uniformly formed. Problems become severe and unrealistic.

[0028]

According to the present invention, as described above, the shifter portion and the non-shifter portion are adjacent to each other, and the shifter portion is formed from the end of the shifter portion to the end of a portion of the non-shifter. A digging type phase shift mask in which a light-shielding layer is formed of a light-shielding film that covers continuously, including the side surface of the digging part (recess). It is possible to provide a phase shift mask capable of uniformly forming a film and a method of manufacturing the same.

[Brief description of the drawings]

FIG. 1 is a process cross-sectional view of a characteristic portion of one example of an embodiment of a method of manufacturing a phase shift mask of the present invention, and FIG.
FIG. 3 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. 2 is a process chart of a comparative example.

FIG. 3A shows a light intensity distribution on a wafer of an adjacent light-transmitting portion (line portion) when the structure of the phase shift mask of the present invention is applied to a line pattern and projected. FIG. 3B is a diagram showing an arrangement of line patterns.

FIG. 4 is a partial cross-sectional view illustrating a conventional digging type phase shift mask.

FIG. 5 is a partial cross-sectional view of a conventional digging type phase shift mask.

FIG. 6 is a partial cross-sectional view in the middle of another manufacturing process different from the method of manufacturing the digging type phase shift mask of the present example.

[Explanation of symbols]

110 Substrate (also referred to as transparent substrate) 115 Dig portion (also referred to as concave portion) 116 Side surface portion 117, 117a Top portion 118, 118a Bottom corner portion 120 Metal film 120A Metal film pattern 125 Opening 130 Dry etching processing gas 135 Resist film 140 Light shielding Film 140A Light-shielding film pattern 145 Opening 150 Shifter part (light-transmitting part) 155 Non-shifter part (light-transmitting part) 250 Light-transmitting part (also referred to as line part or line pattern part) with depth d1 = 0 of concave part 250A Light on wafer Intensity 260 Light transmitting portion with depth d2 of concave portion (also referred to as line portion or line pattern portion) 260A Light intensity on wafer 270 Light transmitting portion (also referred to as line portion or line pattern portion) 275 Pitch between adjacent lines of mask 275A ( Line pitch 280 (light-shielding film) 290 Light intensity profile 295 Threshold value 510 Transparent substrate 520 Light shielding film 521 Opening (light transmitting part) 522, 522A Opening (light transmitting part) 523, 523A Opening (light transmitting part) 524, 524A Opening (light transmitting part) 525 Eaves 530 Shifters 540, 545, 547 Engraved portions (also referred to as concave portions) 610 Transparent substrate 650 Light shielding film 655 Openings (light transmitting portions)

Claims (5)

[Claims] 1. A shifter part and a non-shifter part are adjacent to each other, and a part from an end of the shifter part to an end of a part of the non-shifter is
In order to manufacture a single-sided type substrate dug-in type phase shift mask in which a light-shielding layer pattern made of a light-shielding film continuously covered is formed, including a side surface of a dug-out part (recess) for forming a shifter part. The method of manufacturing a phase shift mask, comprising: (a) opening a dug portion forming region for forming a shifter portion on one surface of a substrate which is transparent to exposure light and is flat on both surfaces; A metal film pattern forming step of forming a metal film pattern, and (b) providing a resist on the metal film pattern if necessary, digging the substrate by dry etching, and setting the wavelength of the exposure light to λ, A dry etching step of making the depth d0 of the dug portion (concave portion) substantially λ / 2 (n−1), where n is the refractive index of
(C) a wet etching step of removing the metal film pattern and performing wet etching on the entire surface of the substrate where the digging portion is formed; and (d) a side surface portion of the digging portion (recess) for forming the shifter portion. A light-shielding film pattern forming step of forming a light-shielding film that continuously covers the entire surface on the side of the digging portion of the substrate and forming a light-shielding film pattern including a light-shielding film that opens a shifter portion and a non-shifter portion by a photoetching method; And a method for manufacturing a phase shift mask. 2. The method for manufacturing a phase shift mask according to claim 1, wherein the wet etching is performed by etching in a range of 10 nm to 100 nm. 3. The method for manufacturing a phase shift mask according to claim 1, wherein the wet etching step is performed by etching with hydrofluoric acid. 4. The method for manufacturing a phase shift mask according to claim 1, wherein in the wet etching step, wet etching is performed with hot alkali. 5. The shifter portion and the non-shifter portion are adjacent to each other, and a portion from an end of the shifter portion to an end of a part of the non-shifter is provided.
A side-digging type substrate dug-in type phase shift mask in which a light-shielding layer pattern made of a light-shielding film continuously covered is formed, including a side surface portion of a dug-out portion (recess) for forming a shifter portion, A phase shift mask formed by the method for manufacturing a photomask according to claim 1.