JPH11352668A - Production of halftone type phase shift mask - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a process for producing a halftone type phase shift mask which obviates the change in the properties of a translucent phase shift layer even if a processing liquid of an alkaline system adopted in the conventional production line as it is in production of this halftone type phase shift mask. SOLUTION: This process for production has the stages for forming the translucent phase shift layer 3, a light shielding layer 4 and a first resist layer 5 on a transparent substrate, removing the first resist layer of a light transparent pattern parts 8, removing the light shielding layer and translucent phase shift layer of the light transparent pattern parts by etching, peeling the first resist layer, laminating a second resist layer 6, removing the second resist layer of the light transparent pattern parts and the peripheral parts 9 of the light transparent patterns, etching the light shielding layer to remove the light shielding layer in the peripheral parts of the light transparent patterns and peeling the second resist layer at the time of producing the halftone type phase shift mask 1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a photomask mainly used in a projection exposure apparatus, and more particularly to a method for transferring a high-resolution pattern by giving a phase difference to projection exposure light passing through the photomask. The present invention relates to a method for manufacturing a phase shift mask.

[0002]

2. Description of the Related Art For example, in a photomask having a pattern formed by using a light-shielding film such as chromium and having no phase shift layer, when a pattern having a narrow line width is transferred onto an exposure object such as a wafer, Resolution is limited. That is, the resolution depends on the wavelength of the exposure light, and for example, the wavelength of the exposure light is changed to g-line (wavelength: 0.43
6 μm), i-line (wavelength: 0.365 μm), KrF
The resolution can be improved by shortening the wavelength to an excimer laser (wavelength: 0.254 μm).

However, each wavelength has its own limitation in resolution. A photomask developed to overcome this limitation is a halftone type phase shift mask. In this halftone type phase shift mask, light interferes between exposure light that has passed through the pattern of the light transmitting portion and whose phase has not been inverted, and exposure light that has passed through the phase shift layer and has been inverted in phase. The resolution is improved.

A light transmission pattern requiring such a phase shift effect is a pattern whose line width is slightly wider than the wavelength of the exposure light, and whose line width is considerably wider than the wavelength of the exposure light. In the case of a pattern, it is not necessary to use the phase shift effect. Further, this halftone type phase shift mask usually has a light transmission pattern, a light transmission pattern peripheral portion including a translucent phase shift layer around the light transmission pattern, a semitransparent phase shift layer around the light transmission pattern peripheral portion, and Although the light transmission pattern is composed of a light shielding layer, if the area around the light transmission pattern is too large, the transferred image to be transferred becomes unclear. There is something that needs to be done.

FIG. 4 is a plan view of an example of a halftone type phase shift mask in a conventional method. In FIG. 4, a halftone type phase shift mask (21) has a light transmission pattern portion (2) on which a translucent phase shift layer (23 ′) and a light shielding layer (24 ′) on a transparent substrate (22) are not formed.
8), a light transmitting pattern peripheral portion (29) formed with a predetermined width around the light transmitting pattern portion (28) by the translucent phase shift layer (23 '), and a light transmitting pattern peripheral portion (29). A light-shielding pattern portion (3) formed around a translucent phase shift layer (23 ') and a light-shielding layer (24').
0), and these patterns are formed by a photo-etching method.

FIG. 5 is a sectional view showing an example of a halftone type phase shift mask in the conventional method shown in FIG. FIG. 6 is an explanatory view showing a manufacturing method of an example of a halftone type phase shift mask in a conventional method in its steps.

FIG. 6A shows a transparent substrate (2).
2) forming a first resist layer (25) on a mask blank (31) having a translucent phase shift layer (23) on the translucent phase shift layer (23) and a light shielding layer (24) on the translucent phase shift layer (23); FIG. This mask blank (31)
Exposure (27) and development are performed on the first resist layer (25) as shown in FIG. 6B, and as shown in FIG. 6C, the light transmission pattern portion (28) and light The first resist layer (25) at the peripheral portion (29) of the transmission pattern is removed.

Next, the obtained light transmission pattern portion (28)
The light-shielding layer (24) is etched using the first resist layer (25 ') in a portion other than the light transmission pattern peripheral portion (29) as an etching resist, as shown in FIG.
The light-shielding layer (24) in the light-transmitting pattern portion (28) and the light-transmitting pattern peripheral portion (29) is removed. The first resist layer (25 ') was peeled off, and as shown in FIG. 6 (e), the light transmitting pattern portion (28) and the light transmitting pattern peripheral portion (2).
9) The light shielding layer (24 ') other than the part is formed.

Subsequently, as shown in FIG. 6 (f), a second resist layer (26) is formed, and exposure (27) and development are performed as shown in FIG. ), The second resist layer (2) of the light transmission pattern portion (28).
6) is removed. Next, the obtained light transmission pattern portion (2
8) The semi-transparent phase shift layer (23) is etched using the second resist layer (26 ') other than that of the second resist layer (26') as an etching resist, and as shown in FIG. The transparent phase shift layer (23) is removed.

The second resist layer (26 ') is peeled and removed,
As shown in FIG. 6 (j), a light transmitting pattern portion (28) on the transparent substrate (22) and a light transmitting pattern peripheral portion formed with a predetermined width around the light transmitting pattern portion (28) 2
9) and a halftone type phase shift mask (21) composed of a light shielding pattern portion (30) formed around a light transmission pattern peripheral portion (29).

However, as a material of the translucent phase shift layer of the halftone type phase shift mask (21), a molybdenum silicide compound (MoSiO, MoSiON, etc.) is used.
In the case of using molybdenum silicide, the molybdenum silicide compound has a property of being altered by being affected by alkali, and thus the above-described production method has the following problems.

That is, for example, in a mask blank of an ordinary photomask, chromium (C
r), a chromium oxide (CrO), or a cleaning liquid used when a photoresist having a product name of EBR-9 or EBR-900, manufactured by Toray Industries, Inc. is used. The stripper is an alkaline solvent or an aqueous solution. For example, FIG. 6 shows a process of manufacturing a halftone type phase shift mask in the above-described conventional method.
In the step of peeling and removing the first resist layer (25 ') shown in (d) and (e), when the film is put into a normal photomask manufacturing line in order to improve the manufacturing efficiency, the peeling solution is made of an alkaline type. Therefore, the translucent phase shift layer is deteriorated, and the phase difference, the transmittance, and the like deviate from the target.

When a cleaning step is added between the steps of FIGS. 6E and 6F, or in the patterning step of the second resist layer (26 ') shown in FIGS. 6G and 6H, or The developer used in the step of peeling and removing the second resist layer (26 ') shown in FIGS. 6 (i) and (j), or in the case where a washing step is added after the step of FIG. 6 (j). Since the cleaning liquid and the stripping liquid are all alkaline solvents or aqueous solutions, the quality of the translucent phase shift layer is altered, and the phase difference, transmittance, and the like deviate from the target. Therefore, in order to avoid such an influence on the translucent phase shift layer, a production line dedicated to the halftone type phase shift mask is provided.

[0014]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and is used in a normal photomask manufacturing process in a halftone phase shift mask manufacturing process. Alkaline developer, cleaning solution, the same alkaline developer as stripper,
An object of the present invention is to provide a method for manufacturing a halftone type phase shift mask in which the phase difference, transmittance and the like do not deviate from the target without deteriorating the translucent phase shift layer even when a cleaning liquid, a stripping liquid or the like is used.

[0015]

According to the present invention, a translucent phase shift layer is provided on a transparent substrate, and a mask blank having a light shielding layer on the translucent phase shift layer. A light-transmitting pattern portion where the light-shielding layer is not formed; a light-transmitting pattern peripheral portion formed with a predetermined width by a translucent phase shift layer around the light-transmitting pattern portion; In a method for manufacturing a halftone type phase shift mask in which a light-shielding pattern portion formed by a semi-transparent phase shift layer and a light-shielding layer is formed by a photo-etching method, (1) a semi-transparent phase shift layer is formed on the entire surface of a transparent substrate. Forming a mask blank by sequentially laminating a light shielding layer; (2) forming a first resist layer on the entire surface of the mask blank; and (3)
(4) removing the first resist layer at a portion to be the light transmission pattern portion; and (4) etching the light shielding layer using the first resist layer other than the portion to be the light transmission pattern portion as an etching resist. (5) removing the light-shielding layer of the light-transmitting pattern portion, and etching the translucent phase shift layer by using the first resist layer and the light-shielding layer as an etching resist except for the portion to be the light-transmitting pattern portion. A step of removing the phase shift layer; (6) a step of peeling off the first resist layer; (7) a step of laminating a second resist layer; (9) removing the second resist layer in a portion to be a light transmitting pattern peripheral portion; and (9) removing the second resist layer other than the portion to be the light transmitting pattern portion and the portion to be the light transmitting pattern peripheral portion. A halftone phase shift mask, comprising: a step of etching the light shielding layer as a etching resist to remove the light shielding layer around the light transmission pattern; and (10) a step of peeling and removing the second resist layer. It is a manufacturing method.

According to the present invention, in the method for producing a halftone phase shift mask according to the present invention, the step (6) of peeling and removing the first resist layer is a step of using an alkaline solvent or aqueous solution. A method for manufacturing a halftone type phase shift mask, characterized in that:

Further, according to the present invention, in the method for producing a halftone phase shift mask according to the present invention, after the step (6) of peeling and removing the first resist layer, cleaning using an alkaline solvent or aqueous solution is performed. A method for manufacturing a halftone type phase shift mask, characterized by adding a step.

According to the present invention, in the method for manufacturing a halftone type phase shift mask according to the present invention, (8) the second resist in a portion to be the light transmitting pattern portion and a portion to be a peripheral portion of the light transmitting pattern portion is provided. A method for producing a halftone phase shift mask, wherein the step of removing the layer is a step using an alkaline developer.

[0019]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below based on one embodiment. FIG. 2 is a plan view of one embodiment of the halftone phase shift mask according to the present invention. In FIG. 2, the halftone type phase shift mask (1) has a light transmission pattern portion (3) on which a translucent phase shift layer (3 ′) and a light shielding layer (4 ″) are not formed on a transparent substrate (2). 8), a light transmitting pattern peripheral portion (9) formed around the light transmitting pattern portion (8) by the translucent phase shift layer (3 ') with a predetermined width, and a light transmitting pattern peripheral portion (9).
Pattern portion (10) formed by a translucent phase shift layer (3 ') and a light shielding layer (4'') around
These patterns are formed by a photo-etching method.

FIG. 3 is a sectional view showing an embodiment of the halftone type phase shift mask of the present invention shown in FIG. FIG. 1 is an explanatory view showing, in the steps, a method of manufacturing a halftone type phase shift mask according to an embodiment of the present invention.

FIG. 1A shows a mask having a translucent phase shift layer (3) on a transparent substrate (2) and a light shielding layer (4) on the translucent phase shift layer (3). The state where the first resist layer (5) is formed on the blank (11) is shown. The mask blank (11) uses quartz as the transparent substrate (2), and the translucent phase shift layer (3)
As MoSiON (molybdenum oxynitride silicide)
And Cr (chromium) was used as the light-shielding layer (4), and these films were formed by a known film forming method.

The thickness of the translucent phase shift layer (3) is 12
00 to 2000, the thickness of the light shielding layer (4) is 300
１1500 ° is preferred. The light-shielding layer (4) is made of Cr (chromium), CrO (chromium oxide), C
rN (chromium nitride), CrON (chromium oxynitride), C
Any of rOCN (chromium oxycarbonitride) may be used, or these may be used by laminating them.

Next, a positive resist is applied on the mask blank (11) as a first resist layer (5) for about 500 hours.
It was formed to a thickness of 0 °. Subsequently, the first resist layer (5) on the mask blank (11) is exposed to an electron beam or a laser beam as shown in FIG.
Then, as shown in FIG. 1C, the first resist layer (5) in the light transmitting pattern portion (8) was removed.

Next, an etching solution prepared by adding perchloric acid to ceric ammonium nitrate is used as an etching resist with the first resist layer (5 ') other than the obtained light transmission pattern portion (8) as an etching resist. Then, the light-shielding layer (4) was etched to remove the light-shielding layer (4) in the light transmission pattern portion (8) as shown in FIG. This etching is a chlorine-based gas mixture of gas and O ₂ (oxygen) such as Cl _2, CH ₂ Cl ₂ may be performed by dry etching using.

Subsequently, the first resist layer (5 ') other than the light transmitting pattern portion (8) and the light shielding layer (4') other than the light transmitting pattern portion (8) are used as an etching resist to form a semi-transparent layer. The phase shift layer (3) is dry-etched using a mixed gas of a fluorine-based gas such as CF ₄ and O ₂ (oxygen), and as shown in FIG. 1 (e), a half of the light transmission pattern portion (8). The transparent phase shift layer (3) was removed.

Next, the first resist layer (5 ') was peeled off using an aqueous solution of dimethylsulfoxide methanol and potassium hydroxide as an alkaline solution.
As shown in (f), the translucent phase shift layer (3 ') and the light-shielding layer (4') were formed in portions other than the light transmission pattern portion (8). Next, washing was performed using an aqueous potassium hydroxide solution as an alkaline aqueous solution.

Subsequently, as shown in FIG. 1 (g), a second resist layer (6) is formed using a positive resist, and is exposed by an electron beam or laser beam as shown in FIG. 1 (h) (7). And a developing process using an alkaline developing solution, and as shown in FIG.
Then, the second resist layer (6) in the peripheral portion (9) of the light transmission pattern was removed. Next, the light-shielding layer (4 ') is etched using the second resist layer (6') in the portion other than the obtained light transmission pattern portion (8) and the light transmission pattern peripheral portion (9) as an etching resist. As shown in FIG. 1 (j), the light-shielding layer (4 ′) in the peripheral portion (9) of the light transmission pattern was removed.

This etching is performed by using ceric nitrate
Using an etching solution prepared by adding perchloric acid to monium
I went there. Also, this etching is performed with Cl_Two, CH_Two
Cl _TwoSuch as chlorine gas and O_Two(Oxygen) mixed gas
Can be performed by dry etching
You. Thereby, the light transmission pattern section (8) and the light transmission pattern are formed.
The light shielding layer (4 '') other than the turn peripheral part (9) is formed.
Done.

Next, the second resist layer (6 ') is peeled off using an organic solvent, and washed using plasma ashing and a strong acid, and as shown in FIG. 1 (k), the transparent substrate (2) is removed. A light transmitting pattern portion (8) above the light transmitting pattern portion, a light transmitting pattern peripheral portion (9) formed with a predetermined width around the light transmitting pattern portion (8), and a light transmitting pattern peripheral portion (9). A halftone type phase shift mask (1) composed of the formed light shielding pattern portion (10) was obtained.

In the method for manufacturing the halftone type phase shift mask (1) according to the present invention as described above, FIG.
As shown in (d), since the translucent phase shift layer which becomes the light transmission pattern peripheral portion (9) is covered by the light shielding layer (4 '), the translucent phase shift layer which becomes the light transmission pattern peripheral portion (9) is formed. The shift layer (3 ') is not affected by the alkaline developing solution and is not deteriorated. As shown in FIGS. 1E and 1F, since the translucent phase shift layer serving as the light transmission pattern peripheral portion (9) is covered with the light shielding layer (4 ′), the light transmission pattern peripheral portion (9). The translucent phase shift layer (3 ′) is not affected by the alkaline stripping solution and does not deteriorate. Also, as shown in FIGS.
Since the translucent phase shift layer serving as the peripheral portion (9) of the light transmitting pattern is covered with the light shielding layer (4 '), the translucent phase shift layer (3') serving as the peripheral portion (9) of the light transmitting pattern is the first. It is not affected by the alkaline developer of the second resist layer (6) and does not deteriorate.

That is, the translucent phase shift layer (3 '), which becomes the peripheral portion (9) of the light transmission pattern, is not affected by an alkaline developing solution, a cleaning solution, a stripping solution or the like, and is not deteriorated. , A halftone type phase shift mask (1) in which the transmittance does not deviate from the target.

[0032]

According to the present invention, when manufacturing a halftone type phase shift mask, (1) a mask blank is prepared by sequentially laminating a translucent phase shift layer and a light shielding layer over the entire surface of a transparent substrate. (2) forming a first resist layer on the entire surface of the mask blank; (3) removing the first resist layer in a portion to be the light transmission pattern portion; (4) Removing the light-shielding layer of the light-transmitting pattern portion by etching the light-shielding layer using the first resist layer other than the portion serving as the light-transmitting pattern portion as an etching resist;
(5) a step of etching the translucent phase shift layer using the first resist layer and the light-shielding layer other than the portion to be the light transmission pattern portion as an etching resist to remove the translucent phase shift layer of the light transmission pattern portion; 6) a step of peeling and removing the first resist layer; (7) a step of laminating a second resist layer; and (8) a step of forming a portion to be the light transmitting pattern portion and a portion to be a peripheral portion of the light transmitting pattern portion. (9) removing the second resist layer, and (9) etching the light-shielding layer using the second resist layer as an etching resist except for the portion to be the light transmission pattern portion and the portion to be the peripheral portion of the light transmission pattern. Removing the light-shielding layer at the periphery;
(10) a step of peeling and removing the second resist layer; therefore, in a step of manufacturing a halftone phase shift mask, an alkaline developer, a cleaning liquid, and a stripping liquid used in a normal photomask manufacturing step. A halftone phase shift mask that does not degrade the translucent phase shift layer and does not deviate from the target, even if the same alkaline developing solution, cleaning solution, stripping solution, etc. are used. Production method.

[Brief description of the drawings]

FIG. 1 is an explanatory view showing a manufacturing process of an embodiment of a halftone phase shift mask according to the present invention.

FIG. 2 is a plan view of one embodiment of a halftone phase shift mask according to the present invention.

FIG. 3 is a cross-sectional view of one embodiment of the halftone phase shift mask according to the present invention shown in FIG.

FIG. 4 is a plan view of an example of a halftone type phase shift mask according to a conventional method.

FIG. 5 is a cross-sectional view of an example of a halftone type phase shift mask in the conventional method shown in FIG.

FIG. 6 is an explanatory view showing a manufacturing process of an example of a halftone type phase shift mask in a conventional method.

[Explanation of symbols]

1, 21: halftone type phase shift mask 2, 22: transparent substrate 3, 23 ... translucent phase shift layer 3 ', 23' ... translucent phase shift layer around light transmission pattern portion 4, 24: light shielding layer 4 '', 24 ': light-shielding layer around the light-transmitting pattern peripheral part 4': light-shielding layer other than the light-transmitting pattern part 5, 25 ... first resist layer 5 ': first resist layer 25' other than the light-transmitting pattern part ... First resist layers 6 and 26 except for light transmission pattern portion and light transmission pattern peripheral portion Second resist layer 6 ′... Second resist layer 26 ′ other than light transmission pattern portion and light transmission pattern peripheral portion Second resist layer other than part 7, 27 ... Exposure 8, 28 ... Light transmission pattern part 9, 29 ... Light transmission pattern peripheral part 10, 30 ... Light shielding pattern part 11, 31 ... Mask blank

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Yuki Kikuchi 1-5-1, Taito, Taito-ku, Tokyo Letterpress Printing Co., Ltd. (72) Inventor Yoshiro Yamada 1-15-1 Taito, Taito-ku, Tokyo Letterpress Printing Co., Ltd.

Claims (4)

[Claims] 1. A translucent phase shift layer and a light shielding layer are not formed using a mask blank having a translucent phase shift layer on a transparent substrate and a light shielding layer on the translucent phase shift layer. A light transmitting pattern portion, a light transmitting pattern peripheral portion formed with a predetermined width by a translucent phase shift layer around the light transmitting pattern portion, and a translucent phase shift layer and light shielding around the light transmitting pattern peripheral portion. In a method of manufacturing a halftone type phase shift mask in which a light-shielding pattern portion formed by a layer is formed by a photoetching method,
(1) a step of forming a mask blank by sequentially laminating a translucent phase shift layer and a light shielding layer over the entire surface on a transparent substrate;
(2) a step of forming a first resist layer on the entire surface of the mask blank; (3) a step of removing the first resist layer in a portion to be the light transmitting pattern portion; and (4) a step of transmitting the light A step of etching the light-shielding layer by using the first resist layer other than the part to be the pattern part as an etching resist to remove the light-shielding layer of the light-transmitting pattern part; A step of etching the translucent phase shift layer using the resist layer and the light-shielding layer as an etching resist to remove the translucent phase shift layer in the light transmission pattern portion; and (6) a step of peeling and removing the first resist layer;
(7) a step of laminating a second resist layer; (8) a step of removing the second resist layer in a portion to be the light transmission pattern portion and a portion to be a peripheral portion of the light transmission pattern; (9)
Removing the light-shielding layer around the light-transmitting pattern by etching the light-shielding layer using the second resist layer as an etching resist except for the part to be the light-transmitting pattern part and the part to be the light-transmitting pattern peripheral part; A) removing and peeling off the second resist layer. 2. A halftone phase shift mask according to claim 1, wherein said step (6) of removing and removing said first resist layer is a step of using an alkaline solvent or aqueous solution. Method. 3. The method according to claim 1, wherein a cleaning step using an alkaline solvent or an aqueous solution is added after the step (6) of peeling and removing the first resist layer. A method for manufacturing a halftone phase shift mask. 4. The step (8) of removing the second resist layer in the portion to be the light transmission pattern portion and the portion to be the peripheral portion of the light transmission pattern is a process using an alkaline developer. 4. The method for manufacturing a halftone phase shift mask according to claim 1, wherein the phase shift mask is a halftone type phase shift mask.