JP2003075986A - Method for producing levenson type phase shift mask - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing a Levenson type phase shift mask having excellent resolution and free of defects. SOLUTION: A blank 10 with a light shielding film 21 and a regist layer 31 formed on a transparent substrate 11 is prepared, a mask 20 having a light shielding pattern 21a and transmission regions 22 formed on the transparent substrate 11 is produced by carrying out a series of patterning procedures, and the mask 20 is inspected and corrected. A regist pattern 32a is formed on the light shielding pattern 21a of the mask 20, the transparent substrate 11 is dry-etched to form trenches 12a, a regist pattern 33a is further formed, the prescribed trenches 12a are dry-etched to form trenches 12b and the regist pattern 33a is removed to obtain the objective Levenson type phase shift mask (dual trench system) 100 with the light shielding pattern 21a and the trenches (shifters) 12a and 12b formed on the transparent substrate 11.

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a Levenson-type phase shift mask used for manufacturing a semiconductor integrated circuit such as an LSI. 2. Description of the Related Art In a manufacturing process of a semiconductor integrated circuit,
2. Description of the Related Art High integration and fine patterning of elements and wirings constituting circuits on a silicon wafer or the like are progressing. In the photolithography technique, a photomask is used as a mask for pattern exposure for forming a fine pattern. One type of this photomask is a phase shift mask using a phase shift method. The phase shift method is one of the techniques for improving the resolution when a fine pattern is transferred, and has been actively developed for practical use. In principle, the phase difference of the transmitted light between adjacent regions on the mask is 180
By providing the phase shift unit so that the transmitted light is diffracted and interferes with each other, the light intensity at the boundary is weakened, and as a result, the resolution of the transfer pattern is improved. As a result, the effect of improving the resolution of the fine pattern and improving the depth of focus, which is significantly superior to that of a normal photomask, can be obtained. As one type of the phase shift mask, a Levenson type phase shift mask of a method of forming a phase shifter by forming a transparent substrate by digging by dry etching or the like (for example, Japanese Unexamined Patent Publication No. No. 189468. As an example of a Levenson-type phase shift mask, as shown in FIG.
FIG. 4 shows a repetitive pattern in which a light-shielding pattern 111 and a transparent region
Engraving 121a in transparent area 112 as shown in FIG.
And 121b, and there is a Levenson-type phase shift mask having a shifter structure of a dual trench type in which dug portions having different depths are formed. Hereinafter, an example of a method for manufacturing a Levenson-type phase shift mask (both digging method) will be described with reference to FIGS. First, a transparent substrate 51 made of a quartz substrate or the like is used.
A light shielding film 61 made of a chromium film or the like and a resist layer 71 thereon
A blank 50 on which is formed is prepared (see FIG. 3A). Next, the resist layer 71 is subjected to a series of patterning processes such as pattern exposure and development with an electron beam to form a resist pattern 71a.
The light shielding film 61 is etched using the mask as a mask (FIG. 3).
(B)). Further, using the resist pattern 71a as a mask, the transparent substrate 51 is etched by dry etching to form a dug 52a (see FIG. 3C). Next, the resist pattern 71a is stripped with a dedicated stripper, and a resist is applied by a spinner on a mask on which the digging 52a has been formed to form a resist layer 72 (see FIG. 3D). . Further, the resist layer 72 is subjected to a series of patterning processes such as pattern exposure and development with an electron beam to form a digging 52a at a predetermined position where a shifter is to be formed and a resist pattern 72a having an opening 73 on the light shielding pattern 61a. It is formed (see FIG. 3E). Next, using the resist pattern 72a as a mask, the digging 52a is etched to a predetermined depth by dry etching to form a digging 52b to make a phase difference with the adjacent pattern (FIG. 3 ( f)). Next, the resist pattern 72a is peeled off with a dedicated peeling liquid, and a Levenson-type phase shift mask (double digging method) 200 in which a light-shielding pattern 61a and digging (shifters) 52a and 52b are formed on a transparent substrate 51 is formed. (See FIG. 3 (g)). In the method of manufacturing a Levenson-type phase shift mask, etching of the light-shielding film 61 and etching of the transparent substrate 51 are performed using the resist pattern 71a as a mask. Is difficult. Also, the light shielding film 6
Since the etching of 1 and the etching of the transparent substrate 51 are performed continuously, even if there is a black-based defect in the etching of the light shielding film 61, the etching of the transparent substrate 51 is performed as it is to form a digging (shifter). There is a problem that it becomes. SUMMARY OF THE INVENTION The present invention has been made in consideration of the above problems, and has as its object to provide a method for manufacturing a defect-free Levenson type phase shift mask having excellent resolution. I do. According to the present invention, there is provided a method for manufacturing a Levenson-type phase shift mask, comprising at least the following steps in order to solve the above-mentioned problems. (A) A step of preparing a blank 10 in which a light-shielding film 21 made of a chromium film or the like and a resist layer 31 are formed on a transparent substrate 11 made of a quartz substrate or the like. (B) patterning the resist layer 31 to form a resist pattern 31a;
1a as a mask, the light shielding film 21 is etched, and the resist pattern 31a is peeled off.
(1) a step of forming a mask 20 having a light-shielding pattern 21a and a transparent region 22 on the mask 1; (C) a step of inspecting and repairing the mask 20; (d) forming a resist layer 32 on the mask 20 after the inspection and repair, and performing a series of patterning processes;
Forming a resist pattern 32a on the light-shielding pattern 21a; (E) The transparent substrate 11 is dry-etched using the resist pattern 32a as a mask to form a dug 12a, and the resist pattern 32a is peeled off with a dedicated peeling liquid to form the dug 12a on the transparent substrate 11. Step of manufacturing mask 30. (F) a step of forming a resist layer 33 on the mask 30 and performing a series of patterning processes to form a resist pattern 33a having an opening 34 on a predetermined recess 12a on the mask 30; (G) Using the resist pattern 33a as a mask, the predetermined digging 12a is dry etched to form the digging 12a.
b) forming a resist pattern 33a and stripping the resist pattern 33a with a dedicated stripper. An embodiment of the present invention will be described below. 1 (a) to 1 (g) and 2 (h) to (l)
FIG. 1 is a schematic sectional view showing one embodiment of a method for manufacturing a Levenson-type phase shift mask according to the present invention in the order of steps. In the method of manufacturing the Levenson-type phase shift mask of the present invention, when forming the light-shielding pattern 21a and the dug-down (shifters) 12a and 12b on the transparent substrate 11, first, the transparent substrate 1
After the mask 20 having the light-shielding pattern 21a formed thereon is manufactured, the mask 20 is inspected and corrected to form the digging (shifters) 12a and 12b. Since the correction is performed, the shifter defect caused by the light shielding film becomes zero. In addition, a resist pattern for forming a light-shielding pattern by etching a light-shielding film and a resist pattern for forming a digging (shifter) by etching a transparent substrate can be separately set. The resist thickness can be set, which is particularly advantageous for forming a light-shielding pattern requiring high resolution and high accuracy. FIGS. 1A to 1G and FIGS. 2H to 2 H
The method of manufacturing the Levenson-type phase shift mask of the present invention will be described with reference to (l). First, a blank 10 having a light-shielding film 21 and a resist layer 31 formed of a two-layer film in which a chromium oxide film is formed on a chromium film on a transparent substrate 11 made of synthetic quartz is prepared (see FIG. 1A). . Next, a series of patterning processes such as pattern exposure and development are performed on the resist layer 31 with an electron beam to form a resist pattern 31a (see FIG. 1B). Further, the light-shielding film 21 is etched using the resist pattern 31a as a mask, and the resist pattern 31a is peeled off with a dedicated peeling liquid, thereby producing a mask 20 having the light-shielding pattern 21a and the transmission region 22 formed on the transparent substrate 11 ( FIG. 1 (c)
reference). Next, the mask 20 is inspected by a mask inspection machine. If a black defect and a white defect are found,
(Focused ion beam), correction by sputtering or the like (see FIG. 1D). Next, a resist is applied by a spinner on the mask 20 which has been inspected and repaired to form a resist layer 32 (see FIG. 1E). Further, the light shielding pattern 21
A resist pattern 32a is formed on the light-shielding pattern 21a by performing pattern exposure such as development on the resist layer 32 by pattern exposure with an electron beam in alignment with the resist pattern 32a (see FIG. 1F). Next, the transparent substrate 11 in the transmission region 22 is etched by dry etching using the resist pattern 32a as a mask to form a digging (shifter) 12a (see FIG. 1G). Next, the resist pattern 32a is peeled off with a dedicated peeling liquid, and a mask 30 having a light-shielding pattern 21a and a digging (shifter) 12a formed on the transparent substrate 11 is produced (see FIG. 2 (h)). Further, a resist is applied on the mask 30 by a spinner to form a resist layer 33 (see FIG. 2I). Next, the resist layer 33 is subjected to a series of patterning processes such as pattern exposure and development using an electron beam, and a predetermined digging (shifter) 12a on the mask 30 is performed.
A resist pattern 33a having an opening 34 thereon is formed (see FIG. 2 (j)). Next, a predetermined depth (shifter) 12a is etched to a predetermined depth by dry etching or a combination of dry etching and wet etching using the resist pattern 33a as a mask, so that adjacent depths (shifters) are formed. A digging (shifter) 12b is formed to give a phase difference with 12a (see FIG. 2 (k)). Next, the resist pattern 33a is stripped with a dedicated stripper, and a Levenson-type phase shift mask (both digging method) 100 having a light-shielding pattern 21a and digging (shifters) 12a and 12b formed on a transparent substrate 11 is formed. (See FIG. 2 (l)). According to the method of manufacturing the Levenson-type phase shift mask of the present invention, when the light-shielding pattern 21a and the digging (shifters) 12a and 12b are formed on the transparent substrate 11, After manufacturing the mask 20 on which the light-shielding pattern 21a is formed, the mask 20 is inspected and corrected to form the dug-in (shifters) 12a and 12b. After the light-shielding pattern 21a is formed, the mask inspection and correction is performed. Therefore, the shifter defect caused by the light shielding film becomes zero. In addition, a resist pattern for forming a light-shielding pattern by etching a light-shielding film and a resist pattern for forming a digging (shifter) by etching a transparent substrate can be separately set. The resist thickness can be set, which is particularly advantageous for forming a light-shielding pattern requiring high resolution and high accuracy.

BRIEF DESCRIPTION OF THE DRAWINGS FIGS. 1A to 1G are schematic cross-sectional views showing a part of the steps of one embodiment of a method for manufacturing a Levenson-type phase shift mask of the present invention. 2 (h) to (l) are schematic sectional views showing a part of the steps of one embodiment of a method for manufacturing a Levenson type phase shift mask of the present invention. 3 (a) to 3 (g) are schematic sectional views showing an example of a conventional method for manufacturing a Levenson-type phase shift mask. FIGS. 4A and 4B are explanatory diagrams illustrating a configuration of a Levenson-type phase shift mask. [Description of References] 10, 50 ... Blank 11, 51, 101 ... Transparent substrate 12a, 12b ... Digging (shifter) 20, 30 ... Mask 21, 61 ... Light shielding film 21a, 61a, 111 ... Shielding patterns 22, 62 Transparent regions 31, 32, 33, 71, 72 Resist layers 31a, 32a, 33a, 71a, 72a Resist patterns 34, 73 Openings 100, 200 Levenson-type phase Shift mask

Claims (1)

Claims: 1. A method of manufacturing a Levenson-type phase shift mask, comprising at least the following steps: (A) A step of preparing a blank (10) in which a light-shielding film (21) made of a chromium film or the like and a resist layer (31) are formed on a transparent substrate (11) made of a quartz substrate or the like. (B) patterning the resist layer (31) to form a resist pattern (31a), etching the light shielding film (21) using the resist pattern (31a) as a mask, and removing the resist pattern (31a); After peeling, the light shielding pattern (21) is formed on the transparent substrate (11).
a) producing a mask (20) having a transparent region (22); (C) a step of inspecting and correcting the mask (20); (d) forming a resist layer (32) on the mask (20) after the inspection and correction, and performing a series of patterning processes to form a light-shielding pattern; Forming a resist pattern (32a) on (21a). (E) Using the resist pattern (32a) as a mask, the transparent substrate (11) is dry etched and dug (1).
2a) is formed, and the resist pattern (32a) is peeled off with a dedicated peeling liquid.
A step of producing a mask (30) on which 2a) is formed. (F) A resist layer (33) is formed on the mask (30), a series of patterning processes are performed, and an opening (3) is formed on a predetermined recess (12a) on the mask (30).
Forming a resist pattern (33a) having 4). (G) Using the resist pattern (33a) as a mask, a predetermined recess (12a) is dry etched to form a recess (12b), and the resist pattern (33) is formed.
a) stripping a) with a dedicated stripper.