Photomask, and method for manufacturing photomask

Abstract

To provide: a photomask which prevents electrostatic breakdown of an isolated pattern, and whose application is not limited to a binary mask; and a method for manufacturing the photomask.SOLUTION: A method for manufacturing a photomask having a first isolated pattern 61a, a second isolated pattern 62a and a bridge pattern 63a connecting both isolated patterns. The method includes the steps of: forming a semi-transmissive film 2 and a light-shielding film 3 having conductivity on a transmissive substrate 1; forming a first resist pattern 4a having an opening pattern 4s on the light-shielding film 3; selectively etching the light-shielding film 3 to form an opening OP; forming a second resist pattern 5a having a bridge region 53a covering the opening OP, a first isolated pattern region 51a and a second isolated pattern region 52a on the light-shielding film; and etching the light-shielding film 3 and the semi-transmissive film 2 to form a first isolated pattern 61a, a second isolated pattern 62a and a bridge pattern 63a.SELECTED DRAWING: Figure 5

Description

[Technical field]

[0001] The present invention relates to a photomask and a method for manufacturing a photomask. [Background technology]

[0002] Photomasks used in lithography processes have various patterns formed on an insulating transparent substrate such as quartz. For example, a pattern formed using a metal light-shielding film constitutes a capacitor. When static electricity is generated in the manufacturing process of a photomask, the amount of charge increases, especially in large-area patterns, and discharge occurs between adjacent electrically isolated patterns, which may cause electrostatic breakdown of the pattern. As a countermeasure to this problem, a method is known in which a conductive dummy pattern is formed between adjacent isolated patterns to prevent electrostatic breakdown. Patent Document 1 discloses a method of forming a dummy pattern between isolated (independent) patterns as described above and electrically connecting the isolated patterns. By making the dummy pattern below the resolution limit of the lithography process, it is possible to prevent the transfer of the dummy pattern to the exposure target. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2003-248294 A Summary of the Invention [Problem to be solved by the invention]

[0004] It is difficult to apply a photomask using the above-mentioned dummy pattern to a halftone mask, a phase shift mask, or the like, and the use of the photomask is limited to a binary mask.

[0005] In view of the above problems, an object of the present invention is to provide a photomask manufacturing method and a photomask that prevent electrostatic damage to an isolated pattern and whose applications are not limited to binary masks. [Means for solving the problem]

[0006] The method for producing a photomask according to the present invention includes the steps of: A method for manufacturing a photomask having a first isolated pattern (61a), a second isolated pattern (62a), and a bridge pattern (63a) connecting the first isolated pattern (61a) and the second isolated pattern (62a), A laminated film formation step of forming a semi-transparent film (2) having conductivity on a transparent substrate (1) and a light-shielding film (3) on the semi-transparent film (2); a first etching mask formation step of forming a first resist pattern (4a) having an opening pattern (4s) on the light-shielding film (3); a first patterning step of selectively etching the light-shielding film (3) to form an opening (OP) and removing the first resist pattern (4a); a second etching mask formation step of forming a second resist pattern (5a) on the light-shielding film, the second resist pattern (5a) having a bridge region (53a) covering the opening (OP) and a first isolated pattern region (51a) and a second isolated pattern region (52a) in contact with the bridge region (53a); a second patterning step of etching the light-shielding film (3) and the semi-transmitting film (2) to form the first isolated pattern (61 a), the second isolated pattern (62 a) and the bridge pattern (63 a), and removing the second resist pattern; The present invention is characterized by comprising:

[0007] Further, in the above-mentioned configuration, a method for manufacturing a photomask according to the present invention comprises the steps of: The width (w) of the opening pattern (4s) is equal to or less than the resolution limit of the exposure step using the photomask.

[0008] According to this method for manufacturing a photomask, a photomask can be manufactured that can electrically connect the isolated patterns with a semi-transparent bridge pattern, thereby preventing electrostatic damage to the isolated patterns, and also prevents the bridge pattern from being imaged onto an object to be exposed.

[0009] Further, in the above-mentioned configuration, a method for manufacturing a photomask according to the present invention comprises the steps of: In the first patterning step, After the semi-transparent film (2) is exposed, the semi-transparent film (2) may be partially etched to reduce its thickness.

[0010] According to such a photomask manufacturing method, the transmittance of the bridge pattern can be further increased, which contributes to an expansion of the design margin, etc.

[0011] Further, in the above-mentioned configuration, a method for manufacturing a photomask according to the present invention comprises the steps of: The bridge region (53a) of the second resist pattern (5a) is It may have a filling portion (5f) that fills the opening (OP) and an extension portion (5e) that protrudes from the filling portion (5f) and covers the light-shielding film (3).

[0012] According to such a photomask manufacturing method, the bridge pattern (63a) can be patterned by the filling portion (5f) that is in direct contact with the semi-transparent film (2), and the first isolated pattern (61a) and the second isolated pattern (62a) can also be patterned.

[0013] Further, in the above-mentioned configuration, a method for manufacturing a photomask according to the present invention comprises the steps of: The second patterning step includes: a step of selectively etching the light-shielding film (3); Selectively etching the semi-transparent film (2); may include:

[0014] According to such a method for manufacturing a photomask, the bridge pattern (63a), the first isolated pattern (61a), and the second isolated pattern (62a) can be patterned with good controllability.

[0015] Further, in the above-mentioned configuration, a method for manufacturing a photomask according to the present invention comprises the steps of: In the laminate film forming step, An intermediate film (7) is further formed on the semi-transmissive film (2), and the light-shielding film (3) is formed on the intermediate film (7); In the first patterning step, selectively etching the light-shielding film (3), and then selectively etching the intermediate film (7) to form an opening (OP) exposing a surface of the semi-transparent film (2); In the second patterning step, The light-shielding film (3), the intermediate film (7) and the semi-transmitting film (2) may be etched to form the first isolated pattern (61a), the second isolated pattern (62a) and the bridge pattern (63a).

[0016] According to such a method for manufacturing a photomask, the laminated structure of the semi-transmitting film (2) and the intermediate film (7) is used as a semi-transmitting region, thereby improving the degree of freedom in adjusting the optical characteristics.

[0017] The method for producing a photomask according to the present invention includes the steps of: A method for manufacturing a photomask having a first isolated pattern (61a), a second isolated pattern (62a), and a bridge pattern (63a) connecting the first isolated pattern and the second isolated pattern, a light-shielding film forming step of forming a light-shielding film (3) on a transparent substrate (1) and a covering film (11) made of a material different from that of the light-shielding film (3) on the light-shielding film (3); forming a light-shielding region etching mask (12a, 12b) on the coating film (11); a light-shielding film patterning step of etching the coating film (11) and the light-shielding film (3) to form the first isolated pattern (61a) and the second isolated pattern (62a), and removing the light-shielding region etching masks (12a, 12b); a semi-permeable membrane forming step of forming a semi-permeable membrane (2); a semi-transparent film patterning step of forming a semi-transparent region etching mask (13a) on the semi-transparent film (2), etching and patterning the semi-transparent film (2) and the covering film (11) using the semi-transparent region etching mask (13a) as an etching mask, removing the covering film (11) by over-etching, forming a bridge pattern (63a) made of the semi-transparent film (2), and removing the semi-transparent region etching mask (13a).

[0018] According to this method of manufacturing a photomask, an isolated pattern and a bridge pattern made of different materials are formed in the same layer, and the bridge pattern can prevent electrostatic breakdown between the isolated patterns.

[0019] The photomask according to the present invention comprises: a first isolated pattern (61a) and a second isolated pattern (62a) on a transparent substrate (1), and a bridge pattern (63a) connecting the first isolated pattern (61a) and the second isolated pattern (62a); the first isolated pattern (61a) and the second isolated pattern (62a) are formed by laminating an upper layer film having a light-shielding property and a lower layer film having a semi-transparent property, the bridge pattern (63a) is conductive and semi-transparent, and is connected to the lower film; The photomask is characterized in that the transmittance of the bridge pattern (63a) is higher than the transmittance of the underlying film.

[0020] According to such a photomask, the bridge pattern prevents electrostatic breakdown between isolated patterns, and also contributes to the expansion of design margins, etc.

[0021] Further, the photomask according to the present invention has the above-mentioned configuration, The lower membrane is made of a semi-permeable membrane (2), The bridge pattern (63a) may be formed from a reduced portion of the semi-permeable film (2).

[0022] According to such a photomask, the transmittance of the bridge pattern (63a) can be selectively set to a high value with a simple structure.

[0023] Further, the photomask according to the present invention has the above-mentioned configuration, The bridge pattern (63a) is made of a semi-transparent film (2), The lower layer film may be composed of a laminate of the semi-permeable film (2) and an intermediate film (7) formed on the semi-permeable film (2).

[0024] Such a photomask improves the degree of freedom in adjusting the optical characteristics. Effect of the Invention

[0025] According to the present invention, it is possible to provide a method for manufacturing a photomask that prevents electrostatic damage to an isolated pattern and whose applications are not limited to binary masks, and a photomask. [Brief description of the drawings]

[0026] [Figure 1] FIG. 1 is a schematic diagram showing the main steps of manufacturing a photomask 100 according to the first embodiment. [Diagram 2] FIG. 2 is a schematic diagram showing the main steps of manufacturing the photomask 100 according to the first embodiment. [Diagram 3] FIG. 3 is a schematic diagram showing the main steps of manufacturing the photomask 100 according to the first embodiment. [Figure 4] FIG. 4 is a schematic diagram showing the main steps of manufacturing the photomask 100 according to the first embodiment. [Diagram 5] FIG. 5 is a schematic diagram showing the main steps of manufacturing the photomask 100 according to the first embodiment. [Figure 6] FIG. 6 is a cross-sectional view showing a process of reducing the thickness of the semi-transparent film 2. As shown in FIG. [Figure 7] FIG. 7 is a schematic diagram showing the main steps of manufacturing the photomask 100 according to the second embodiment. [Figure 8] FIG. 8 is a schematic diagram showing the main steps of manufacturing the photomask 100 according to the second embodiment. [Figure 9] FIG. 9 is a schematic diagram showing the main steps of manufacturing the photomask 100 according to the second embodiment. [Figure 10] FIG. 10 is a schematic diagram showing the main steps of manufacturing the photomask 100 according to the second embodiment. [Figure 11] FIG. 11 is a schematic diagram showing the main steps of manufacturing the photomask 100 according to the second embodiment. [Figure 12] FIG. 12 is a schematic diagram showing the main steps of manufacturing the photomask 100 according to the third embodiment. [Figure 13] FIG. 13 is a schematic diagram showing the main steps of manufacturing the photomask 100 according to the third embodiment. [Figure 14] FIG. 14 is a schematic diagram showing the main steps of manufacturing the photomask 100 according to the third embodiment. [Figure 15] FIG. 15 is a schematic diagram showing a process of forming a semi-transmitting region in the photomask 100 according to the third embodiment. [Figure 16] FIG. 16 is a schematic diagram showing a step of forming a semi-transmitting region in the photomask 100 according to the third embodiment. [Figure 17] FIG. 17 is a schematic diagram showing the main steps of manufacturing the photomask 100 according to the fourth embodiment. [Figure 18] FIG. 18 is a schematic diagram showing the main steps of manufacturing the photomask 100 according to the fourth embodiment. [Figure 19] FIG. 19 is a schematic diagram showing the main steps of manufacturing the photomask 100 according to the fourth embodiment. [Figure 20] FIG. 20 is a schematic diagram showing the main steps of manufacturing the photomask 100 according to the fifth embodiment. [Figure 21] FIG. 21 is a schematic diagram showing the main steps of manufacturing the photomask 100 according to the fifth embodiment. [Figure 22] FIG. 22 is a schematic diagram showing the main steps of manufacturing the photomask 100 according to the fifth embodiment. [Figure 23] FIG. 23 is a schematic diagram showing the main steps of manufacturing the photomask 100 according to the fifth embodiment. [Figure 24] FIG. 24 is a schematic diagram showing the main steps of manufacturing the photomask 100 according to a modification of the fifth embodiment. [Diagram 25] FIG. 25 is a schematic diagram showing the main steps of manufacturing the photomask 100 according to a modification of the fifth embodiment. [Figure 26] FIG. 26 is a schematic diagram showing the main steps of manufacturing the photomask 100 according to a modification of the fifth embodiment. [Figure 27] FIG. 27 is a schematic diagram showing main steps of manufacturing the photomask 100 according to a modification of the fifth embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0027] Hereinafter, the embodiments of the present invention will be described with reference to the drawings. However, the following embodiments are not intended to limit the scope of the present invention. In addition, the same reference numerals are used for the same or similar components, and the description thereof may be omitted.

[0028] Furthermore, terms used in this specification that specify shapes, geometric conditions, and the extent thereof, such as "parallel," "orthogonal," "same," "flush," and the like, as well as values ​​of length and angle, are not to be bound by their strict meanings, but are to be interpreted to include the range within which similar functions can be expected.

[0029] (Embodiment 1) 1, 2, 3, 4 and 5 are schematic diagrams showing main manufacturing steps of a photomask 100 according to the first embodiment. A method for manufacturing the photomask 100 will now be described with reference to the drawings.

[0030] <Layered film formation process: Preparation of photomask blanks> As shown in the cross-sectional view of FIG. 1(A), a transparent substrate 1 made of quartz glass or the like is prepared. The transparent substrate 1 has a transmittance of 90% or more (90%≦transmittance) for representative wavelengths (including but not limited to, for example, i-line, h-line, and g-line) contained in exposure light used to transfer a pattern formed on a photomask to an object to be exposed in a lithography process using a photomask 100. The configuration of the photomask 100 described below is applicable not only to binary photomasks but also to halftone masks and phase shift masks.

[0031] Next, a semi-transparent film 2 having semi-transparency, such as a film made of a material such as a metal compound (Cr-based compound, Ni-based compound, Ti-based compound, etc.), a metal silicide compound (e.g., Mo silicide, Zr silicide, etc.), or a metal nitride (ZrN, etc.), is formed on the transparent substrate 1 by a sputtering method, a deposition method, etc. (for example, but not limited to, a film thickness of 5 to 20 [nm]). Zr silicide can be preferably used because of its high transmittance. Note that metal nitride, which is a type of metal compound, can be easily formed into a film by deposition or sputtering (reactive sputtering) in a nitriding atmosphere, and it is also possible to form different materials using the same source by controlling the atmosphere. Moreover, having semi-transparency means that the transmittance for the representative wavelength contained in the exposure light is lower than that of the transparent substrate 1 and higher than that of the light-shielding film 3 described below. Moreover, the semi-transmissive film 2 and the light-shielding film 3 are made of a conductive film.

[0032] In addition, when the semi-transparent film 2 is used as a half-tone film, the transmittance of the semi-transparent film 2 can be set to 10 to 70% (10%≦transmittance≦70%) and the phase shift amount can be set small (approximately 0°, for example 0 to 20°) for the representative wavelength of the exposure light used in the lithography process using the photomask 100. Furthermore, the semi-transparent film 2 may be used as a phase shift film. When used as a phase shift film, the transmittance of the semi-transparent film 2 is set to 3 to 15% (3%≦transmittance≦15%) and the phase shift amount is set to approximately 180° (160°≦phase shift amount≦200°), more preferably 170°≦phase shift amount≦190°, for the representative wavelength contained in the exposure light. The optical characteristics of the semi-transparent film 2, such as the transmittance, may be set according to the intended use. When used as a binary mask, it is also possible to use a photomask blank prepared using a semi-transparent film 2 having optical properties suited to the above-mentioned intended use.

[0033] Next, a light-shielding film 3 having a light-shielding property is formed on the semi-transparent film 2 by a sputtering method, a vapor deposition method, or the like. (For example, but not limited to, a film thickness of 50 [nm] to 100 [nm]) is formed, and a photomask blank 10 having a semi-transparent film 2 and a light-shielding film 3 on a transparent substrate 1 is obtained. The light-shielding film 3 is set, for example, to have an optical density (OD value) of 2.7 or more, and is made of a material having different etching characteristics from the semi-transmitting film 2, for example, a metal compound, a Si-based compound, or a metal silicide compound. For example, the semi-transmissive film 2 may be made of a metal silicide, and the light-shielding film 3 may be made of a Cr film, but the present invention is not limited to this.

[0034] It is also possible to shorten the manufacturing time by preparing a photomask blank in advance in which the semi-transmitting film 2 and the light-shielding film 3 are formed in this order on the transparent substrate 1 by the above process.

[0035] <First etching mask forming process> Next, as shown in the cross-sectional views of FIG. 1(B) and FIG. 1(C), a first photoresist film 4 is formed on the light-shielding film 3 by a coating method or the like, and is patterned by exposure and development using laser drawing or the like to form a first photoresist pattern 4a (a first etching mask pattern Also called ) is formed. As shown in the plan view of FIG. 1(D), the first photoresist pattern 4a has an opening 4s (opening pattern 4s) in an area for forming a pattern (bridge pattern) that electrically connects adjacent isolated patterns. The width w of the opening 4s is set to the width of the bridge pattern to be formed, and is set to a width equal to or smaller than the resolution limit in the lithography process using the photomask 100. FIG. 1(B) shows a cross section taken along line AA in FIG. 1(D), and FIG. 1(C) shows a cross section taken along line BB in FIG. 1(D).

[0036] <First patterning step: Definition of bridge pattern forming area> 2(A), the first photoresist pattern 4a is used as an etching mask to selectively etch and pattern the light-shielding film 3 with respect to the semi-transmitting film 2, thereby forming a first light-shielding film pattern 3a. Although known wet etching can be suitably adopted as the etching, dry etching may also be used. The first light-shielding film pattern 3a has an opening OP, and the surface of the semi-transmitting film 2 is exposed at the opening OP. The width w of the opening OP is set to a width equal to or smaller than the resolution limit in the lithography process using the photomask 100. The opening OP defines a region in which a bridge pattern is to be formed.

[0037] <First etching mask removal process> Thereafter, as shown in the cross-sectional views of FIG. 2(B) and FIG. 2(C) and the plan view of FIG. 2(D), the first photoresist pattern 4a is removed by ashing, wet cleaning, or the like.

[0038] <Second Etching Mask Pattern Forming Step> Next, as shown in the cross-sectional view of FIG. 3(A), a second photoresist film 5 is formed on the first light-shielding film pattern 3a and the semi-transparent film 2 exposed at the opening OP by a coating method or the like, and is patterned by exposure using laser drawing or the like and development to form a second photoresist pattern 5a (second etching mask pattern).

[0039] 3(A) shows a cross section taken along line AA in FIG. 3(C), and FIG. 3(B) shows a cross section taken along line BB in FIG. 3(C). The same applies to the relationships between the cross sections and plan views below.

[0040] As shown in the cross-sectional view of FIG. 3(B) and the plan view of FIG. 3(C), the second photoresist pattern 5a has an area corresponding to the first isolated pattern. Area( First isolated pattern area 51a says ), the area corresponding to the second isolated pattern Area( Second isolated pattern area 52a says ), and the area corresponding to the bridge pattern Area( Bridge area 53a says ) The bridge region 53a is configured to cover an area obtained by adding a predetermined width d (extended width d) to the periphery of the opening OP. For example, in the y direction shown in Figures 3B and 3C, the width L of the bridge region 53a is greater than the width w of the opening OP by a predetermined extension width d on both sides, i.e., L = w + 2d. The predetermined extension width d can be set to a length equivalent to the alignment error of a drawing device for forming the second photoresist pattern 5a (a length equal to the alignment error). Even if misalignment of the drawing device occurs, the bridge region 53a of the second photoresist pattern 5a can cover the opening OP. In the example shown in Fig. 3(C), only a part of the first isolated pattern region 51a is shown, and the shape of the first isolated pattern region 51a may be the same as or different from the shape of the second isolated pattern region 52a. The shapes of the first isolated pattern region 51a and the second isolated pattern region 52a are not limited to those shown in Fig. 3 etc. The shapes of the isolated patterns are similar in other embodiments.

[0041] The second photoresist pattern 5a in the bridge region 53a is in direct contact with the semi-transparent film 2 at the opening OP, and indirectly in contact with the semi-transparent film 2 via the light-shielding film 3 at other locations (regions determined by the expansion width d). Also, as shown in the cross-sectional view of Figure 3(B), the cross-sectional shape of the photoresist film in the bridge region 53a is T-shaped, and has a filling portion 5f that fills the opening OP, and an extension portion 5e (cover portion) that protrudes from the filling portion 5f by a distance d to the light-shielding films 3 on both sides and covers the light-shielding films 3. The shape of the filling portion 5f is determined by the opening OP. As will be described later, the filling portion 5f that is in direct contact with the surface of the semi-transparent film 2 serves as an etching mask for forming a bridge pattern.

[0042] As shown in FIG. 3A, an isolated pattern exists on the end side of the opening OP in the longitudinal direction (X direction), and a bridge region 53a is continuous with a first isolated pattern region 51a and a second isolated pattern region 52a. As described later, the side etching causes the periphery of the light-shielding film 3 to recede from the periphery of the first isolated pattern region 51a and the second isolated pattern region 52a of the second photoresist pattern 5a. Therefore, both ends in the longitudinal direction of the filling portion 5f for defining the bridge pattern of the semi-transmitting film 2 protrude a distance D (protrusion distance D) into the first isolated pattern region 51a and the second isolated pattern region 52a. By protruding both ends of the filling portion 5f, the distance D is set so that both ends of the bridge pattern of the semi-transmitting film 2 are flush with the first isolated pattern 61a and the second isolated pattern 62a after the side etching of the light-shielding film 3. This configuration also makes it possible to absorb misalignment of the drawing device. This also applies to the other embodiments.

[0043] The first isolated pattern region 51a and the second isolated pattern region 52a are shaped to extend from the outer edges of the first isolated pattern 61a and the second isolated pattern 62a (shown in FIG. 5C) by a width d (extended width d).

[0044] <Second patterning process: formation of isolated pattern and bridge pattern> Next, as shown in the cross-sectional views of FIGS. 4(A) and 4(B), the first light-shielding film pattern 3a is selectively etched and patterned using the second photoresist pattern 5a as an etching mask to form a second light-shielding film pattern 3b (a first isolated light-shielding film pattern Also called ), a third light-shielding film pattern 3c (a second isolated light-shielding film pattern Also called Since the semi-transmitting film 2 is made of a material having etching characteristics different from those of the light-shielding film 3, the first light-shielding film pattern 3a can be selectively etched under the condition that the semi-transmitting film 2 is not etched.

[0045] 4(B), over-etching is performed until the light-shielding film 3 present under the region of the extension width d of the bridge region 53a is removed. The second photoresist pattern 5a directly contacts the semi-transmitting film 2 only in the region corresponding to the region of the opening OP, i.e., only in the filling portion 5f filled in the opening OP. Therefore, both end faces of the filling portion 5f that contact the first isolated pattern region 51a and the second isolated pattern region 52a contact the light-shielding film 3 (the second light-shielding film pattern 3b, the third light-shielding film pattern 3c) (see Figure 4(A)), but on other side wall surfaces of the filling portion 5f, the second photoresist pattern 5a does not contact the light-shielding film 3 (see Figure 4(B)).

[0046] As shown in FIG. 4A, the end of the first light-shielding film pattern 3a is recessed from the outer edge of the second photoresist pattern 5a by a distance D (amount of side etching D) due to overetching. In order to remove the light shielding film 3 in the region of the extension width d, the amount of over-etching, that is, the amount of side etching D is set to be equal to or larger than the extension width d, and preferably can be set to be equal to the extension width d. Since the light-shielding film 3 under the region of the extension width d is etched and the end of the first light-shielding film pattern 3a is side-etched, a known wet etching method, which is an isotropic etching method, can be suitably used.

[0047] Since the light-shielding film 3 in the bridge region 53a is removed (see FIG. 4(B)), the first light-shielding film pattern 3a is separated into a second light-shielding film pattern 3b and a third light-shielding film pattern 3c. The second light-shielding film pattern 3b and the third light-shielding film pattern 3c constitute the light-shielding films of the first isolated pattern and the second isolated pattern, respectively.

[0048] In addition, since the first light-shielding film pattern 3a is etched by isotropic etching, the end faces (outer edges) of the first light-shielding film pattern 3a in the first isolated pattern region 51a, the second isolated pattern region 52a, and the bridge region 53a are recessed, and the shapes of the second light-shielding film pattern 3b and the third light-shielding film pattern 3c are determined. At this time, the end face of the second light-shielding film pattern 3b on the bridge region 53a side and the end face of the third light-shielding film pattern 3c on the bridge region 53a side become flush with the respective end faces in the longitudinal direction of the filling portion 5f that determines the shape of the bridge pattern 63a. (See FIG. 5(C) described later.)

[0049] Next, as shown in the cross-sectional views of Figures 4(C) and (D), the semi-transparent film 2 is selectively etched and patterned using the second photoresist pattern 5a, the second light-shielding film pattern 3b, and the third light-shielding film pattern 3c as etching masks to form a semi-transparent film pattern 2a. Since the semi-transmitting film 2 is made of a material having etching characteristics different from those of the light-shielding film 3, the semi-transmitting film 2 can be selectively etched under conditions in which the light-shielding film 3 is not etched. In the area where the semi-transparent film 2 has been etched, the surface of the transparent substrate 1 is exposed. By adjusting the amount of over-etching of the semi-transmitting film 2, the edges of the light-shielding film 3 and the semi-transmitting film 2 can be aligned (made flush) as shown in FIG. 4(C). The light-shielding film 3 and the semi-transmitting film 2 can be etched by known wet etching, which is isotropic etching.

[0050] In the bridge region 53a, as shown in FIG. 4(D), the semi-transparent film pattern 2a is etched and patterned using the region 5s of the second photoresist pattern 5a that is in direct contact with the semi-transparent film pattern 2a, particularly the filling portion 5f, as an etching mask. The semi-transparent film pattern 2a in contact with the filling portion 5f of the second photoresist pattern 5a is left behind to form a conductive bridge pattern 63a. Since the shape (size) of the filling portion 5f is determined by the shape of the photoresist embedded in the opening OP, the opening OP indirectly determines the shape (dimension) of the bridge pattern 63a.

[0051] 4, the light-shielding film 3 and the semi-transmitting film 2 are recessed by a distance D from the outer edge of the second photoresist pattern 5a, thereby forming a first isolated pattern 61a and a second isolated pattern 62a. By selectively etching the light-shielding film 3 and the semi-transmitting film 2 in sequence, the bridge pattern 63a, the first isolated pattern 61a, and the second isolated pattern 62a can be patterned with good controllability. In addition, since the light-shielding film 3 and the semi-transmitting film 2 are etched using the same second photoresist pattern 5a, 1st and 2nd Isolated putter No.6 In the patterns 1a and 62a, the pattern of the upper light-shielding film 3 and the pattern of the lower semi-transmitting film 2 are not misaligned.

[0052] The shape of the opening 4s (for example, the distance in the x-direction in the example shown in FIG. 1(D)) is set so that both ends of the opening 4s of the first photoresist pattern 4a (both ends of the filling portion 5f of the second photoresist pattern 5a) contact (are flush with) the end faces of the first isolated pattern 61a and the second isolated pattern 62a, respectively.

[0053] <Second etching mask removal process> Next, as shown in FIGS. 5(A) and 5(B), the second photoresist pattern 5a is removed. A laminated structure portion of the second light-shielding film pattern 3b and the semi-transmitting film pattern 2a constitutes a first isolated pattern 61a, and a laminated structure portion of the third light-shielding film pattern 3c and the semi-transmitting film pattern 2a constitutes a second isolated pattern 62a. That is, the first isolated pattern 61a and the second isolated pattern 62a are composed of a laminated film of a lower layer film and an upper layer film, with a semi-transmitting film 2 in the lower layer and a light-shielding film 3 in the upper layer. On the other hand, the bridge pattern 63a is composed of the semi-transmitting film 2 in the lower layer film. The semi-transmitting films 2 of the first isolated pattern 61a, the second isolated pattern 62a and the bridge pattern 63a are continuous, and the semi-transmitting film 2 in the lower layer film is conductive. Therefore, the first isolated pattern 61a and the second isolated pattern 62a are electrically connected via the bridge pattern 63a. In this manner, pattern formation for preventing electrostatic breakdown between adjacent isolated patterns on the photomask 100 is completed. The width of the bridge pattern 63a is set to be equal to or less than the resolution limit of the exposure light for transferring the pattern of the photomask, thereby preventing the pattern from being transferred to an object to be exposed.

[0054] Even when the width of the bridge pattern 63a is set to be equal to or less than the resolution limit, if the bridge pattern 63a is made of a light-shielding film, minute protrusion-like shape abnormalities may occur due to the proximity effect at the junctions between the bridge pattern 63a and the first isolated pattern 61a and the second isolated pattern 62a. However, even in such a case, by making the bridge pattern 63a of a semi-transparent film, it is possible to prevent or reduce the occurrence of the above-mentioned shape abnormalities of the isolated patterns due to the proximity effect. The shape of the bridge pattern 63a is not limited to the I-shaped rectangle as shown in Fig. 5(C) and may be, for example, an L-shape, and is not limited to the example shown in Fig. 5(C). The same applies to other embodiments, and the shape of the bridge pattern 63a can be set appropriately. In addition, for example, a T-shaped bridge pattern or the like is not excluded from electrically connecting three (or more) isolated patterns.

[0055] If necessary, the photomask 100 can be further patterned. For example, when used as a halftone mask, patterning can be performed to form a halftone region, and when used as a phase shift mask, patterning can be performed to form a phase shift region.

[0056] The transmittance of the bridge pattern 63a can also be adjusted. For example, when the photomask is used as a halftone mask or a phase shift mask, the transmittance, which is an optical property of the semi-transmitting film 2 of the photomask blank 10, is set to a value suitable for the application of the photomask. On the other hand, it is preferable that the bridge pattern 63a has a high transmittance in order to prevent imaging on the exposure target. Therefore, the transmittance of the bridge pattern 63a may be selectively made higher than that of the semi-transmitting film 2 in other regions, as described below. By increasing the transmittance of the semi-transparent film 2, it is possible to obtain an effect of alleviating the above-mentioned restriction on the width of the bridge pattern 63a, thereby contributing to an increase in the degree of freedom (or margin) of design or manufacturing conditions. For example, it is possible to determine the transmittance of the semi-transparent film 2 based on the exposure dose in the lithography process and the exposure sensitivity of the photoresist on the object to be exposed, and to relax (or eliminate) the restriction that the width of the bridge pattern 63a (or the width w of the opening 4s) must be equal to or less than the resolution limit of the exposure light. The width of the bridge pattern below is similar to that of the other embodiments.

[0057] <Transmittance adjustment> Hereinafter, a method for adjusting the transmittance of the bridge pattern 63a will be described with reference to the cross-sectional view of FIG. After the step shown in FIG. 2(A), the film thickness of the semi-transparent film 2 at the opening OP can be adjusted to adjust the transmittance of the semi-transparent film 2. First, similar to the process shown in FIG. 1.Using the photoresist pattern 4a as an etching mask, the light-shielding film 3 is selectively etched and patterned with respect to the semi-transmitting film 2 to form a first light-shielding film pattern 3a and expose the surface of the semi-transmitting film 2. In this process, the semi-transmitting film 2 is not etched. after that, 1. Using the photoresist pattern 4a as an etching mask, the semi-transparent film 2 is (partially) etched selectively with respect to the light-shielding film 3, thereby reducing the film thickness of the semi-transparent film 2 below the opening 4s (opening OP). By adding a process of partially etching the semi-transparent film 2 to the process shown in FIG. 2(A), the transmittance of the bridge pattern 63a can be adjusted to be high. Then, the process shown in FIG. 2(B) is carried out, and the subsequent processes are the same as those described above.

[0058] As a means for reducing the thickness of the semi-transparent film 2, wet etching can be adopted, but the present invention is not limited to this. in particular, 1. Using the photoresist pattern 4a as a mask, AP plasma (atmospheric pressure plasma) is irradiated for a predetermined time so as to cover the openings 4s, thereby reducing the film thickness of the semi-transparent film 2, thereby increasing the transmittance of the bridge pattern 63a. The transmittance can be adjusted by adjusting the exposure time of the AP plasma. Note that, although Ar plasma is preferably used as the plasma, plasma using a reactive gas such as a fluorine-based gas may also be used.

[0059] The semi-transmitting film 2s ( below Bridge area semi-permeable membrane 2s says ) can be selectively reduced in thickness. That is, the thickness t1 of the bridge region semi-transmitting film 2s can be made smaller than the thickness t0 of the semi-transmitting film 2 below the light-shielding film 3 (t0>t1). As a result, it is possible to selectively increase the transmittance of only the bridge pattern 63a without changing the optical properties of the semi-transmitting film 2 other than the bridge pattern 63a. Furthermore, since there is no need to form a new etching mask for additional etching of the semi-transparent film 2, the transmittance of the bridge pattern 63a can be easily adjusted.

[0060] Therefore, while using a photomask blank having a semi-transparent film 2 optimized for the application of the photomask (e.g., a half-tone mask, a phase shift mask), the transmittance of the bridge pattern 63a can be selectively (independently) set to a high value. As a result, it is possible to ease restrictions on the pattern width of the bridge pattern 63a and contribute to an increase in the process margin.

[0061] Before the semi-transmitting film 2 is patterned into the shape of the bridge pattern 63a, a SiO 2 film having an opening 4s is formed. 1. Since the semi-transmitting film 2 is etched and reduced using the photoresist pattern 4a, the process shown in FIG. 6 does not affect the size of the line width w of the bridge pattern 63a.

[0062] (Embodiment 2) A second embodiment of the present invention will now be described. The second embodiment is particularly advantageous when the photomask 100 is configured as a half-tone mask, a phase shift mask, or the like. 7, 8, 9, 10 and 11 are schematic diagrams showing main steps of manufacturing the photomask 100 according to the second embodiment.

[0063] FIG. 7A is a cross-sectional view illustrating the main steps for preparing a photomask blank 20. As shown in FIG. Similar to the process shown in FIG. 1(A), a semi-transparent film 2 having semi-transparency is formed on a transparent substrate 1. Next, the intermediate film 7 is formed on the semi-transparent film 2 by a deposition method, a sputtering method, or the like. The intermediate film 7 has semi-transparency and can be selected from materials that can be used for the semi-transparent film 2 described above, but is made of a material that has etching characteristics different from those of the light-shielding film 3 described below and the semi-transparent film 2 described above. For example, the semi-transmitting film 2 can be a metal silicide, the intermediate film 7 can be a Cr compound, and the light-shielding film 3 can be a Ni film, or the intermediate film 7 can be a metal silicide different from that of the semi-transmitting film 2, and the light-shielding film 3 can be a Cr film, but this is not limited to these. The intermediate film 7 also functions as an etching stopper, and has a function of adjusting the optical characteristics due to its laminated structure with the semi-transparent film 2, improving the degree of freedom in adjusting the optical characteristics. For example, a laminate of the intermediate film 7 (second layer) and the semi-transmitting film 2 (first layer) can be used as a halftone film or a phase shift film. In other words, it is also possible to interpret the semi-transmitting film provided below the light-shielding film 3 as being composed of a laminate structure of the first layer (semi-transmitting film 2) and the second layer (intermediate film 7). The optical characteristics of the halftone film or phase shift film are as described above.

[0064] 7(B), a first photoresist pattern 4a is formed on the light-shielding film 3 in the same manner as in the steps shown in FIGS. 1(B) and (C). The light-shielding film 3 has etching characteristics different from those of the semi-transmitting film 2. The width w of the opening 4s is the same as in the first embodiment.

[0065] Next, as shown in the cross-sectional view of FIG. 7(C), the first photoresist pattern 4a is used as an etching mask to selectively etch and pattern the light-shielding film 3 and the intermediate film 7 with respect to the semi-transmitting film 2, thereby forming a first light-shielding film pattern 3a and a first intermediate film 7. pattern Form 7a. Alternatively, the light-shielding film 3 may be selectively etched with respect to the intermediate film 7, patterned to form the first light-shielding film pattern 3a, and then the intermediate film 7 may be selectively etched with respect to the semi-transparent film 2 and the light-shielding film 3, patterned to form the first intermediate film pattern 7a. The laminated pattern STa of the first light-shielding film pattern 3a and the first intermediate film pattern 7a has an opening OP.

[0066] Next, as shown in the cross-sectional view of FIG. 7(D), the first photoresist pattern 4a is removed.

[0067] Next, as shown in the cross-sectional view of FIG. 8(A) (similar to the process shown in FIG. 3(A)), a second photoresist pattern 5a is formed on the first light-shielding film pattern 3a and the semi-transmitting film 2 exposed in the opening OP. The second photoresist pattern 5a corresponds to the first isolated pattern. The 1 isolated pattern area 51 a、 Corresponding to the second isolated pattern The 2 isolated pattern area 52 a、 and bridge patterns Rubu Ridge Region 53 a It has.

[0068] Next, as shown in the cross-sectional views of Figures 8(B) and (C), the first light-shielding film pattern 3a is selectively etched and patterned with respect to the first intermediate film pattern 7a using the second photoresist pattern 5a as an etching mask to form a second light-shielding film pattern 3b and a third light-shielding film pattern 3c. As shown in FIG. 8C, the light-shielding film 3 is over-etched until the light-shielding film 3 present under the region of the extension width d of the bridge region 53a is removed. The process shown in Figures 8(B) and (C) is similar to that shown in Figures 4(A) and (B), but differs in that the first light-shielding film pattern 3a is selectively formed relative to the first intermediate film pattern 7a, and the first intermediate film pattern 7a functions as an etching stopper.

[0069] 8(D) and (E), the second photoresist pattern 5a, the second light-shielding film pattern 3b, and the third light-shielding film pattern 3c are used as an etching mask to selectively etch the first intermediate film pattern 7a with respect to the second light-shielding film pattern 3b, the third light-shielding film pattern 3c, and the semi-transparent film 2 to form the second intermediate film pattern 7b and the third intermediate film pattern 7c. In this process, the second light-shielding film pattern 3b, the third light-shielding film pattern 3c, and the semi-transparent film 2 are not etched. The light-shielding film 3 and the intermediate film 7 can be etched by known wet etching, which is isotropic etching.

[0070] 8(D), the ends of the second light-shielding film pattern 3b and the third light-shielding film pattern 3c are recessed from the ends of the second photoresist pattern 5a. Therefore, the second light-shielding film pattern 3b and the third light-shielding film pattern 3c essentially serve as an etching mask, and the ends of the light-shielding film 3 and the intermediate film 7 can be aligned. Furthermore, since there is no light-shielding film 3 covering the intermediate film 7 below the region of extension width d in the bridge region 53a, the intermediate film 7 present below this region is also removed in the same manner, as shown in Figure 8(E).

[0071] Next, as shown in the cross-sectional views of Figures 9(A) and (B), the second photoresist pattern 5a, the second light-shielding film pattern 3b, the third light-shielding film pattern 3c, the second intermediate film pattern 7b and the third intermediate film pattern 7c are used as etching masks to selectively etch and pattern the semi-transparent film 2 to form a semi-transparent film pattern 2a. Since the semi-transparent film 2 is selectively etched, the second light-shielding film pattern 3b, the third light-shielding film pattern 3c, the second intermediate film pattern 7b, and the third intermediate film pattern 7c are not etched, and therefore the sidewalls of the second light-shielding film pattern 3b, the third light-shielding film pattern 3c, the second intermediate film pattern 7b, and the third intermediate film pattern 7c do not recede. As shown in FIG. 9(A), the end faces of the third light-shielding film pattern 3c, the third intermediate film pattern 7c, and the semi-transmitting film pattern 2a can be aligned flush.

[0072] Next, as shown in the cross-sectional view of FIG. 9(C) and the plan view of FIG. 9(D), the second photoresist pattern 5a is removed. The layered structure of the second light-shielding film pattern 3b, the second intermediate film pattern 7b and the semi-transparent film pattern 2a constitutes a first isolated pattern 61b, and the layered structure of the third light-shielding film pattern 3c, the third intermediate film pattern 7c and the semi-transparent film pattern 2a constitutes a second isolated pattern 62b. The bridge pattern 63b made of the semi-transparent film pattern 2a is made of the same film as the semi-transparent film pattern 2a of the first isolated pattern 61b and the semi-transparent film pattern 2a of the second isolated pattern 62b, and is formed continuously only with the semi-transparent film pattern 2a. As a result, the bridge pattern 63b electrically connects the first isolated pattern 61b and the second isolated pattern 62b (similar to the configuration shown in FIG. 5(C)). In this manner, pattern formation for preventing electrostatic breakdown between adjacent isolated patterns on the photomask 100 is completed. The first isolated pattern 61b, the second isolated pattern 62b, and the bridge pattern 63b correspond to the above-mentioned first isolated pattern 61a, the second isolated pattern 62a, and the bridge pattern 63a.

[0073] A method for forming a half-tone region on the photomask 100 to manufacture a half-tone mask will now be described. The same applies to the case where a phase shift region is formed in photomask 100 in order to manufacture a phase shift mask.

[0074] As shown in the cross-sectional view of FIG. 10(A) and the plan view of FIG. 10(B), a third photoresist film 8 is formed, and a halftone region 9a (semi-transmissive region 9a) is formed by exposure and development processes using laser drawing or the like. Also called ) is formed.

[0075] Next, as shown in the cross-sectional view of FIG. 10(C), the light-shielding film 3 of the second isolated pattern 62b is selectively etched using the third photoresist pattern 8a as an etching mask. The intermediate film 7 functions as an etching stopper, and the underlying semi-transparent film 2 is not etched. Alternatively, the light-shielding film 3 of the second isolated pattern 62b may be selectively etched using an etchant that etches only the light-shielding film 3 and does not etch the intermediate film 7 and the semi-transmitting film 2.

[0076] Next, as shown in the cross-sectional view of FIG. 11(A) and the plan view of FIG. 11(B), the third photoresist pattern 8a is removed. The halftone region 9 a is formed by laminating a semi-transmissive film 2 and an intermediate film 7 . On the other hand, the bridge pattern 63b is composed only of the semi-transmitting film 2. Therefore, the transmittance of the bridge pattern 63b can be set higher than the transmittance of the halftone region 9a. That is, the transmittance of bridge pattern 63b can be selectively set high while the optical characteristics of halftone region 9a are set to conditions necessary for photomask 100 to function as a halftone mask. Therefore, it is possible to effectively prevent transfer of bridge pattern 63b to an object to be exposed while enabling the formation of halftone region 9a having necessary optical characteristics. In the above, an example has been shown in which halftone region 9a is formed adjacent to second isolated pattern 62b, but the location of halftone region 9a is arbitrary.

[0077] For example, the entire light-shielding film 3 on the second isolated pattern 62b may be selectively removed to form a half-tone region. In this case, the third photoresist pattern 8a is shaped to open the second isolated pattern 62b in the process shown in Figures 10(A) and 10(B). In the etching process shown in Figure 10(C), the light-shielding film 3 is selectively etched with respect to the semi-transmitting film 2 and intermediate film 7, so that the bridge pattern 63b is not etched. The bridge pattern 63b can connect adjacent light-shielding patterns (light-shielding regions) and half-tone patterns (half-tone regions). Similarly, the bridge pattern 63b can also connect adjacent half-tone patterns (semi-transmitting regions).

[0078] Although the formation of the halftone region has been described above, the same applies to the formation of the phase shift region. The optical characteristics of the laminate of the intermediate film 7 and the semi-transmitting film 2 may be appropriately set according to the region to be formed. Specific examples of the optical characteristics required for the halftone region and the phase shift region are as described above.

[0079] 7(C), the semi-transparent film 2 exposed in the opening OP may be partially etched to reduce the film thickness of the semi-transparent film 2. This increases the transmittance of the semi-transparent film 2 in the opening OP, and further increases the transmittance of the bridge pattern 63b.

[0080] (Embodiment 3) A third embodiment of the present invention will now be described. 12, 13 and 14 are schematic diagrams showing main steps of manufacturing the photomask 100 according to the third embodiment.

[0081] As shown in the cross-sectional view of FIG. 12(A), a light-shielding film 3 is formed on a transparent substrate 1, and a covering film 11 is formed on the light-shielding film 3. Alternatively, a photomask blank in which the light-shielding film 3 has been formed on the transparent substrate 1 in advance may be prepared, and the covering film 11 may be laminated on the light-shielding film 3 . The optical characteristics of the light-shielding film 3 are as described above.

[0082] The coating film 11 formed on the light-shielding film 3 may be a film made of a material such as a metal compound, a metal silicide compound, or a metal nitride, and may be formed on the light-shielding film 3 by a deposition method, a sputtering method, or the like. The covering film 11 is made of a material having etching characteristics different from those of the light-shielding film 3 and the semi-transmitting film 2, and can function as an etching stopper film. Note that the light-shielding film 3 and the semi-transmitting film 2 may be made of films having different etching characteristics, or may be made of films having the same etching characteristics.

[0083] Next, as shown in the cross-sectional view of FIG. 12(B), a fourth photoresist film 12 is formed on the coating film 11, and patterned by an exposure process such as laser drawing and a development process to form fourth photoresist patterns 12a and 12b (light-shielding region etching masks). Also calledThe fourth photoresist patterns 12a and 12b function as an etching mask for the light-shielding regions, and define (determine) the shapes of the first isolated pattern 61a and the second isolated pattern 62a, respectively.

[0084] Next, as shown in the cross-sectional view of FIG. 12(C), using the fourth photoresist patterns 12a, 12b as a mask, the coating film 11 is selectively etched with respect to the light-shielding film 3 to expose the surface of the light-shielding film 3, thereby forming coating film patterns 11a, 11b. Thereafter, the exposed light-shielding film 3 is selectively etched with respect to the covering film 11 using the fourth photoresist patterns 12a and 12b as a mask to expose the surface of the transparent substrate 1, and a light-shielding film pattern 3d (first isolated light-shielding film pattern Also called ), and the light-shielding film pattern 3e (second isolated light-shielding film pattern Also called The light-shielding film pattern 3d and the light-shielding film pattern 3e correspond to the second light-shielding film pattern 3b and the third light-shielding film pattern 3c, respectively.

[0085] Next, as shown in the cross-sectional view of FIG. 12(D) and the plan view of FIG. 12(E), the fourth photoresist patterns 12a and 12b are removed by ashing or the like. As shown in FIG. 12(E), the coating film patterns 11a and 11b have pattern shapes corresponding to a first isolated pattern 61c and a second isolated pattern 62c, respectively, which will be described later.

[0086] Next, as shown in the cross-sectional view of Fig. 13(A), the semi-transparent film 2 is formed by a sputtering method, a vapor deposition method, or the like. The semi-transparent film 2 is formed on the exposed surface of the transparent substrate 1 and the surfaces of the coating film patterns 11a and 11b. The optical characteristics, etc. of the semi-transparent film 2 are as described above.

[0087] Next, as shown in the cross-sectional view of FIG. 13(B) and the plan view of FIG. 13(C), a fifth photoresist 13 is formed by a coating method or the like, and is patterned by an exposure process using laser drawing or the like and a development process to form a fifth photoresist pattern 13a (a semi-transparent region etching mask). Also calledThe fifth photoresist pattern 13a determines the shape of a bridge pattern 63c, which will be described later, and functions as a semi-transparent region etching mask. The width w of the fifth photoresist pattern 13a corresponds to the width of the bridge pattern 63c, and is preferably set to be equal to or smaller than the resolution limit for the exposure light in the lithography process. The fifth photoresist pattern 13a has ends that overlap with the coating film patterns 11a and 11b, respectively, at portions 13c and 13d, each of which has a length d. Therefore, the fifth photoresist pattern 13a has a central portion 13b that defines the shape of the bridge pattern 63c, and overlapping portions 13c and 13d located on both ends thereof.

[0088] The length d is set to the value of the alignment error (or equal to or greater than the value of the alignment error) of a drawing device that draws the fifth photoresist pattern 13a. The length is also set to a length that allows the coating film 11 to be removed by etching (side etching) the coating film 11 below the overlapping portions 13c and 13d, which will be described later. Generally, the value of the alignment error is sufficiently smaller (not limited to, equal to or less than a fraction of the resolution limit, for example, equal to or less than about a quarter micron) than the pattern size to be drawn (for example, not limited to, equal to or less than 1 μm). Therefore, by setting the length d to the value of the alignment error, the coating film 11 below the overlapping portions 13c and 13d can be sufficiently removed.

[0089] Next, as shown in the cross-sectional view of FIG. 14(A), the semi-transparent film 2 is selectively etched with respect to the coating film 11 and patterned using the fifth photoresist pattern 13a as a mask. The pattern made of the semi-transparent film 2 is a semi-transparent film corresponding to a bridge pattern. pattern 2a and the portions existing under the overlapping portions 13c and 13d of the fifth photoresist pattern 13a. Half Permeable membrane over - Wrapping section 2b, 2 c Yes. Thereafter, using the fifth photoresist pattern 13a as a mask, the coating film patterns 11a and 11b are etched selectively with respect to the semi-transmitting film 2 and the light-shielding film 3. As a result, the surface of the light-shielding film 3 is exposed.

[0090] Part of the coating film 11 (coating film overlapping portions 11c, 11d) remains below the overlapping portions 13c, 13d of the fifth photoresist pattern 13a. As shown in FIG. 14(A), the semi-permeable membrane overlapping portions 2b, 2c and the coating membrane overlapping portions 11c, 11d remain below the overlapping portions 13c, 13d, and the semi-permeable membrane overlapping portions 2b, 2c are present on the coating membrane overlapping portions 11c, 11d.

[0091] Next, as shown in the cross-sectional view of FIG. 14(B), the coating film overlapping parts 11c and 11d are selectively etched (side-etched) and removed. The semi-transparent film overlapping parts 2b and 2c are removed by lift-off. As a result, 1st and 2nd The semi-transmitting film 2 is not present on the light-shielding film patterns 3a and 3b. 1st and 2nd It is sandwiched between the light-shielding film patterns 3a and 3b. In this step, the semi-transparent film 2 is not etched, so there is no effect (change) on the size of the pattern formed of the semi-transparent film 2 other than the overlapping portion.

[0092] Next, as shown in the cross-sectional view of FIG. 14(C) and the plan view of FIG. 14(D), the fifth photoresist pattern 13a is removed. The light-shielding film pattern 3d and the light-shielding film pattern 3e respectively constitute a first isolated pattern 61c and a second isolated pattern 62c, and are semi-transmissive films. pattern 2a constitutes a bridge pattern 63c. The first isolated pattern 61c and the second isolated pattern 62c are electrically connected by the bridge pattern 63c.

[0093] The first isolated pattern 61c and the second isolated pattern 62c are made of a light-shielding film 3, and the bridge pattern 63c is made of a semi-transmitting film 2. Although they are made of different materials, the first isolated pattern 61c, the second isolated pattern 62c, and the bridge pattern 63c are arranged in the same layer. Both ends of the bridge pattern 63c contact the walls of the first isolated pattern 61c and the second isolated pattern 62c. That is, a wall surface on one end side of the bridge pattern 63c contacts a wall surface of the first isolated pattern 61c, and a wall surface on the other end side of the bridge pattern 63c contacts a wall surface of the second isolated pattern 62c. The semi-transparent film 2 constituting the bridge pattern 63c does not run onto the surfaces of the first isolated pattern 61c and the second isolated pattern 62c. 14 shows an example in which the thickness of the semi-transmitting film 2 constituting the bridge pattern 63c is equal to the thickness of the light-shielding film 3 constituting the first isolated pattern 61c and the second isolated pattern 62c, but this is not limiting. Preferably, the thickness of the semi-transmitting film 2 is smaller than the thickness of the light-shielding film 3.

[0094] The first isolated pattern 61c, the second isolated pattern 62c, and the bridge pattern 63c correspond to the above-mentioned first isolated pattern 61a, the second isolated pattern 62a, and the bridge pattern 63a, respectively.

[0095] In order to manufacture a half-tone mask, a phase shift mask, or the like, a semi-transparent region made of the semi-transparent film 2 may be formed on the photomask 100 as necessary. The process of forming the semi-transmissive region will be described below.

[0096] In the step shown in FIG. 13(B), for example, as shown in the cross-sectional view of FIG. 15(A) and the plan view of FIG. 15(B), a fifth photoresist pattern 13e is formed in a predetermined region where a semi-transmissive region is to be formed. 15(A) and (B) show an example in which a semi-transmitting region is formed so as to be in contact with the second isolated pattern 62c. The fifth photoresist pattern 13e has an overlapping portion 13f having a length d on the coating film pattern 11a. 15(A) and 15(B), the fifth photoresist pattern 13e may be formed apart from the second isolated pattern 62c, in which case there is no overlapping portion 13f.

[0097] Thereafter, similar to the process shown in FIG. 14(A), the semi-transparent film 2 and the coating film patterns 11a, 11b are selectively etched and patterned with respect to the light-shielding film 3 using the fifth photoresist pattern 13e as an etching mask, as shown in the cross-sectional view of FIG. 15(C). The semi-transparent film 2 is patterned to form a semi-transparent film pattern 2d. In addition, a semi-transparent film overlapping portion 2e and a coating film overlapping portion 11e are left under the overlapping portion 13f.

[0098] Thereafter, similarly to the step shown in FIG. 14(B), the semi-transmitting membrane overlapping portions 2b, 2c, and 2e and the coating membrane overlapping portions 11c, 11d, and 11e are removed as shown in the cross-sectional view of FIG. 16(A).

[0099] Thereafter, similarly to the step shown in FIG. 14(C), the fifth photoresist patterns 13a and 13e are removed as shown in the cross-sectional view of FIG. 16(B) and the plan view of FIG. 16(C). The semi-transparent film pattern 2d constitutes a semi-transparent region 9c, and the semi-transparent film pattern 2a constitutes a bridge pattern 63c. It should be noted that semi-transmitting region 9c corresponds to semi-transmitting region 9a (halftone region 9a).

[0100] Although the bridge pattern 63c has been described as an example of connecting between the first isolated pattern 61c and the second isolated pattern 62c, which are light-shielding regions, this is not limited to this, and the bridge pattern may be configured to electrically connect between the light-shielding region and the semi-transparent region, and between the semi-transparent region and another semi-transparent region.

[0101] (Embodiment 4) A fourth embodiment of the present invention will now be described. 17, 18 and 19 are schematic diagrams showing main steps of manufacturing the photomask 100 according to the fourth embodiment.

[0102] 1(A), as shown in the cross-sectional view of Fig. 17(A), a semi-transparent film 2 having semi-transparency is formed on a transparent substrate 1, and a light-shielding film 3 having light-shielding properties is formed on the semi-transparent film 2. The semi-transparent film 2 and the light-shielding film 3 have different etching characteristics. The optical characteristics of the semi-transmitting film 2 and the light-shielding film 3 are as described above.

[0103] Next, as shown in the cross-sectional view of FIG. 17(B) and the plan view of FIG. 17(C), a sixth photoresist 14 is formed on the light-shielding film 3, and is patterned by exposure using laser drawing or the like and development to form a sixth photoresist pattern 14a. The sixth photoresist pattern 14a has a first isolated pattern region 51b, a second isolated pattern region 52b, and a bridge region 53b. The first isolated pattern region 51b, the second isolated pattern region 52b, and the bridge region 53b correspond to the above-mentioned first isolated pattern region 51a, the second isolated pattern region 52a, and the bridge region 53a, respectively. The width w of the bridge region 53b of the sixth photoresist pattern 14a determines the width of the bridge pattern, and can be set to a width equal to or smaller than the resolution limit for the exposure light in the lithography process.

[0104] Next, as shown in the cross-sectional view of FIG. 18(A), the sixth photoresist pattern 14a is used as an etching mask to etch the light-shielding film 3 selectively with respect to the semi-transmitting film 2, thereby forming a light-shielding film pattern 3f. Thereafter, as shown in the cross-sectional view of FIG. 18(B) and the plan view of FIG. 18(C), the semi-transmitting film 2 is selectively etched with respect to the light-shielding film 3 to form a semi-transmitting film pattern 2f.

[0105] Next, as shown in the cross-sectional view of Fig. 19(A) and the plan view of Fig. 19(B), the light-shielding film pattern 3f is side-etched to remove the light-shielding film pattern 3f in the bridge region 53b, so that only the semi-transmitting film pattern 2f remains in the bridge region 53b. The light-shielding film pattern 3f is etched from both sides. If the side etching amount of the light-shielding film pattern 3f is Sd, the light-shielding film pattern 3f in the bridge region 53b is removed if Sd is equal to or greater than half the width w of the light-shielding film pattern 3f in the bridge region 53b (Sd≧w / 2). Preferably, the side etching amount Sd of the light-shielding film pattern 3f is set to half the width w of the light-shielding film pattern 3f.

[0106] Next, as shown in the plan view of FIG. 19(C) and the cross-sectional view of FIG. 19(D), the sixth photoresist pattern 14a is removed by ashing or the like. By side etching, the light-shielding film pattern 3f is divided into a light-shielding film pattern 3g constituting the first isolated pattern 61a and a light-shielding film pattern 3h constituting the second isolated pattern 62a. Further, the sidewall surface of the light-shielding film pattern 3g and the sidewall surface of the light-shielding film pattern 3h are set back from the sidewall surface of the light-shielding film pattern 3f by a distance Sd.

[0107] The first isolated pattern 61a has a laminated structure of a light-shielding film pattern 3g and a semi-transmitting film pattern 2f, and the second isolated pattern 62a has a laminated structure of a light-shielding film pattern 3h and a semi-transmitting film pattern 2f. The semi-transmitting film pattern 2f located between the first isolated pattern 61a and the second isolated pattern 62a constitutes a bridge pattern 63a.

[0108] In addition, a semi-transmitting film pattern 2f is provided around the light-shielding film pattern 3g and the light-shielding film pattern 3h. Therefore, the contact area between the bridge pattern 63a and the first isolated pattern 61a (or the second isolated pattern 62a) is expanded, and it is possible to prevent current concentration at the contact area. For example, between special large-area isolated patterns, it is possible to prevent or reduce the risk of destruction of the bridge pattern 63a (or the isolated pattern) at the boundary due to an abnormally large current concentration at the boundary between the bridge pattern 63a and the isolated pattern.

[0109] (Embodiment 5) The fifth embodiment of the present invention will now be described. 20, 21, 22, and 23 are schematic diagrams showing main manufacturing steps of the photomask 100 according to the embodiment 5. Figures 24, 25, 26, and 27 are schematic diagrams showing main manufacturing steps of the photomask 100 according to a modification of the embodiment 5.

[0110] Similar to the process shown in FIG. 12(A), a light-shielding film 3 having a light-shielding property is formed on a transparent substrate 1, and a covering film 11 is formed on the light-shielding film 3, as shown in the cross-sectional view of FIG. 20(A). The optical characteristics, etching characteristics, etc. of the light-shielding film 3 are as described above. The coating film 11 has the above-mentioned etching characteristics, etc. The coating film 11 can function as an etching stopper film.

[0111] Next, as shown in the cross-sectional view of Figure 20(B) and the plan view of Figure 20(C), a seventh photoresist 15 is formed on the coating film 11 and patterned by exposure using laser drawing or the like and development to form a seventh photoresist pattern 15a. The seventh photoresist pattern 15a has a first isolated pattern region 51c, a second isolated pattern region 52c, and a bridge region 53c. The first isolated pattern region 51c, the second isolated pattern region 52c, and the bridge region 53c correspond to the above-mentioned first isolated pattern region 51a, the second isolated pattern region 52a, and the bridge region 53a, respectively. FIG. 20B is a cross-sectional view of the bridge region 53c in FIG. 20C, that is, taken along line BB.

[0112] The bridge region 53c of the seventh photoresist pattern 15a has two line portions 15L. The seventh photoresist pattern 15a also has a space portion 15s sandwiched between the line portions 15L. Both ends of the space portion 15s are sandwiched between the first isolated pattern region 51c and the second isolated pattern region 52c. As a result, the space portion 15s forms an opening. One end of the space portion 15s in the longitudinal direction is flush with the boundary between the first isolated pattern region 51c and the line portion 15L, and the other end is flush with the boundary between the second isolated pattern region 52c and the line portion 15L. For example, when the two line portions 15L are rectangular as shown in Fig. 20(C), the longitudinal length of the line portion 15L and the longitudinal length of the space portion 15s are equal.

[0113] The width w of the space portion 15s is set to a value equal to or less than the resolution limit of the exposure light in the lithography process. The width WL of the line portion 5L is a value determined by the alignment error of the drawing device, and is a value larger than the alignment error, and can be set, without limitation, to, for example, 1.5 or 2 times the alignment error (specifically, for example, about 0.5 μm). In general, the alignment error of the drawing device is sufficiently smaller than the pattern width drawn by the drawing device, and therefore the width WL can be set to a value equal to or less than the resolution limit of the lithography process.

[0114] Next, as shown in the cross-sectional view of FIG. 20(D), the coating film 11 and the light-shielding film 3 are etched using the seventh photoresist pattern 15a as an etching mask to form a coating film pattern 11a and 1.A laminated pattern composed of the light-shielding film pattern 3a is formed. Although etching may be performed using an etchant capable of etching both the coating film 11 and the light-shielding film 3, it is preferable to selectively etch the coating film 11 and then selectively etch the light-shielding film 3. Selective etching improves the accuracy of patterning.

[0115] Next, as shown in the cross-sectional view of FIG. 20(E), the seventh photoresist pattern 15a is removed. 20(D) and (E) correspond to the cross section taken along line BB in FIG. 20(C), and show cross sections of bridge region 53c. The covering film pattern 11a of the bridge region 53c and 1. The light-shielding film pattern 3a is composed of a covering film line pattern 11L and a light-shielding film line pattern 3L, which are spaced apart by a distance w and have a width WL.

[0116] As shown in the plan view of Figure 21(A) and the cross-sectional view of Figure 21(B), the coating film pattern 11a has a coating film line pattern 11L and a first isolated coating film pattern 11j and a second isolated coating film pattern 11k corresponding to the first isolated pattern region 51c and the second isolated pattern region 52c, respectively. Corresponding to the space portion 15s of the seventh photoresist pattern 15a, an opening SL (a slit portion) is formed between the coating film line pattern 11L and the light-shielding film line pattern 3L. Also called ) is formed. In the opening SL transparency The substrate 1 is exposed, and the width of the opening SL (or the distance between the two light-shielding film line patterns 3L) is w. The positions of both ends of the opening SL are determined by the boundaries between the bridge region 53c and the first isolated pattern region 51c and the second isolated pattern region 52c. FIG. 21B is a cross section taken along line CC in FIG. 21A.

[0117] As shown in FIG. 21(B), 1.The light-shielding film pattern 3a has a light-shielding film line pattern 3L, a first isolated light-shielding film pattern 3j, and a second isolated light-shielding film pattern 3k below the covering film line pattern 11L, the first isolated covering film pattern 11j, and the second isolated covering film pattern 11k, respectively. The opening SL is surrounded by a coating film line pattern 11L, a first isolated coating film pattern 11j and a second isolated coating film pattern 11k, and is also surrounded by a light shielding film line pattern 3L, a first isolated light shielding film pattern 3b and a second isolated light shielding film pattern 3c.

[0118] Next, as shown in the plan view of FIG. 21(C) and the cross-sectional view of FIG. 21(D), a semi-transparent film 2 is formed, and then an eighth photoresist 16 is formed on the semi-transparent film 2 and patterned by exposure using laser drawing or the like and development to form an eighth photoresist pattern 16a. The optical characteristics, etching characteristics, etc. of the semi-transparent film 2 are as described above. FIG. 21D is a cross-sectional view in the region of the covering film line pattern 11L and the light-shielding film line pattern 3L in FIG. 21C.

[0119] The eighth photoresist pattern 16a covers the opening SL. The periphery of the eighth photoresist pattern 16a extends from the periphery of the opening SL toward the covering film line pattern 11L (light-shielding film line pattern 3L) by a distance d, and also extends toward the first isolated covering film pattern 11j (first isolated light-shielding film pattern 3b) and the second isolated covering film pattern 11k (second isolated light-shielding film pattern 3c) by a distance d. The eighth photoresist pattern 16a has a central portion 16c located above the opening SL, and an extension portion 16e provided around the central portion 16c and located above the coating film pattern 11a. The width of the extension portion 16e is a distance d. By setting the distance d to the alignment error of the writing device for the eighth photoresist pattern 16a, the eighth photoresist pattern 16a can cover the opening SL even if misalignment occurs.

[0120] Next, as shown in the plan view of Figure 22(A) and the cross-sectional view of Figure 22(B), using the eighth photoresist pattern 16a as an etching mask, the semi-transparent film 2 is selectively etched and patterned with respect to the coating film 11 and the light-shielding film 3 to expose the coating film pattern 11a. As shown in the cross-sectional view of FIG. 22(B), a semi-transparent photoresist is formed under the central portion 16c of the eighth photoresist pattern 16a. Membrane The turn 2a is formed, and the semi-transparent film remaining portion 2r is formed under the extension portion 16e. The semi-transparent film remaining portion 2r is formed on the coating film pattern 11a.

[0121] Next, as shown in the cross-sectional view of FIG. 22(C) and the plan view of FIG. 22(D), the coating film pattern 11a is selectively etched with respect to the semi-transmitting film 2 and the light-shielding film 3. 1. The light-shielding film pattern 3a is exposed. The semi-transparent film remaining portion 2r on the coating film pattern 11a is removed, and the semi-transparent film covered by the central portion 16c is Membrane The turn 2 a remains on the transparent substrate 1 .

[0122] Next, as shown in the plan view of FIG. 23(A) and the cross-sectional view of FIG. 23(B), the eighth photoresist pattern 16a is removed. semi-transparent Membrane The turn 2a and the light-shielding film line patterns 3L provided in contact with both sides thereof constitute a bridge pattern. The light-shielding film line pattern 3L electrically connects the first isolated light-shielding film pattern 3j and the second isolated light-shielding film pattern 3k, thereby preventing electrostatic breakdown between the first isolated light-shielding film pattern 3j and the second isolated light-shielding film pattern 3k.

[0123] Since the width of the light-shielding film line pattern 3L is set to be equal to or smaller than the resolution limit, it is not transferred onto an object to be exposed in the lithography process. Also, semi-transparent Membrane The width of the turn 2a is set to be equal to or less than the resolution limit, and furthermore, the turn 2a has a high transmittance, so that the turn 2a is not transferred onto an object to be exposed in the lithography process.

[0124] 21(C), a semi-transparent region may be further provided in the eighth photoresist pattern 16a as appropriate. The semi-transparent film 2 is patterned using the semi-transparent region provided in the eighth photoresist pattern 16a as an etching mask, so that a semi-transparent region of a desired shape made of the semi-transparent film 2 can be formed in the photomask 100. By providing a semi-transparent region, the photomask 100 can be configured as a half-tone mask or a phase shift mask.

[0125] In the above embodiment, the bridge pattern is semi-transparent. Membrane The light-shielding film line patterns 3L are formed on both sides of the turn 2a. As described below, the light-shielding film line patterns 3L are removed to form a semi-transparent Membrane It is also possible to configure it from only turn 2a. A modification of the fifth embodiment will now be described. 24, 25, 26 and 27 are schematic diagrams showing main steps of manufacturing a photomask 100 according to a modification of the fifth embodiment.

[0126] As shown in the plan view of FIG. 24(A), a seventh photoresist pattern 15a' is formed in the same manner as in the process shown in FIG. 20(C). The seventh photoresist pattern 15a' corresponds to the first isolated pattern. The 1 isolated pattern area 51 c、 Corresponding to the second isolated pattern The 2 isolated pattern area 52 c、 and bridge patterns Rubu Ridge Region 53 c It has. The first isolated pattern region 51c, the second isolated pattern region 52c, and the bridge region 53c correspond to the above-mentioned first isolated pattern region 51a, the second isolated pattern region 52a, and the bridge region 53a, respectively.

[0127] The bridge region 53c of the seventh photoresist pattern 15a' has two line portions 15L'. The seventh photoresist pattern 15a' also has a space portion 15s' sandwiched between the line portions 15L', and the space portion 15s' forms an opening. The line portion 15L' corresponds to the line portion 15L, and the space portion 15s' corresponds to the space portion 15s. The line portion 15L' has a width WL, and the space portion 15s' has a width w.

[0128] However, unlike the space portion 15s, both ends of the space portion 15s' are extended by a distance D' (extension distance) to the first isolated pattern region 51c and the second isolated pattern region 52c. away) It stands out. As described later, in the process of removing the light-shielding film line pattern 3L, the peripheral portions of the first isolated light-shielding film pattern 3j and the second isolated light-shielding film pattern 3k are recessed by side etching, and the distance D' is set so that they are flush with both ends of the space portion 15s'. Specifically, the distance D' is set to the width WL (or WL or more) of the light-shielding film line pattern 3L, and is preferably set to be equal to the width WL.

[0129] Next, as shown in the plan view of FIG. 24(B) and the cross-sectional views of FIG. 24(C) and FIG. 24(D), similarly to the steps shown in FIG. 20(D), FIG. 20(E) and FIG. 21(A), the coating film 11 and the light-shielding film 3 are etched using the seventh photoresist pattern 15a′ as an etching mask to form coating film patterns 11a and 1. A laminated pattern made of the light-shielding film pattern 3a is formed, and then the seventh photoresist pattern 15a' is removed. FIG. 24C corresponds to a cross section taken along line CC in FIG. 24B, and FIG. 24D corresponds to a cross section taken along line C'-C' in FIG. 24B. As shown in FIG. 24(B), the two coating film line patterns 11L of the coating film pattern 11a are spaced apart from each other by a distance w.

[0130] As shown in FIG. 24(C), the coating film pattern 11a has a coating film line pattern 11L, a first isolated coating film pattern 11j, and a second isolated coating film pattern 11k. 1. The light-shielding film pattern 3a includes a light-shielding film line pattern 3L, a first isolated light-shielding film pattern 3j, and a second isolated light-shielding film pattern 3k. The light-shielding film line pattern 3L, the first isolated light-shielding film pattern 3j, and the second isolated light-shielding film pattern 3k are provided below the coating film line pattern 11L, the first isolated coating film pattern 11j, and the second isolated coating film pattern 11k, respectively. Similarly to the two coating film line patterns 11L of the coating film pattern 11a, 1. The two light shielding film line patterns 3L of the light shielding film pattern 3a are spaced apart from each other by a distance w. An opening SL' (slit portion) is formed between the two coating film line patterns 11L (and the light-shielding film line pattern 3L). Also called ) is formed.

[0131] In the cross section shown in FIG. 24(D), the first isolated light shielding film pattern 3j (and the first isolated covering film pattern 11j) and the second isolated light shielding film pattern 3k (and the second isolated covering film pattern 11k) are separated by an opening SL'. The length of the opening SL' in the x direction is longer by a distance 2D' than the length of the light-shielding film line pattern 3L (coating film line pattern 11L) in the x direction.

[0132] Next, as shown in the plan view of Fig. 25(A) and the cross-sectional view of Fig. 25(B), a semi-transparent film 2 is formed in the same manner as in the process shown in Fig. 21(C), and then an eighth photoresist 16' is formed on the semi-transparent film 2 and patterned by exposure and development using laser drawing or the like to form an eighth photoresist pattern 16a'. Fig. 25(B) corresponds to the cross section shown in Fig. 24(D). The eighth photoresist pattern 16a' covers the opening SL'. The periphery of the eighth photoresist pattern 16a' is extended outward by a distance d from the periphery of the opening SL', similar to the above-mentioned eighth photoresist pattern 16a. As described above, the distance d can be set to account for the alignment error of the drawing device.

[0133] As shown in Figure 25 (B), the eighth photoresist pattern 16a' has a central portion 16c' located above the opening SL' and an extension portion 16e' provided around the central portion 16c' and located above the coating film pattern 11a (coating film line pattern 11L, first isolated coating film pattern 11j and second isolated coating film pattern 11k).

[0134] Next, as shown in the plan view of FIG. 25(C) and the cross-sectional view of FIG. 25(D), similar to the process shown in FIGS. 22(A) and (B), the semi-transparent film 2 is etched and patterned using the eighth photoresist pattern 16a′ as an etching mask to expose the coating film pattern 11a. The dotted line in FIG. 25(C) indicates the semi-transmitting film pattern 2a formed in the opening SL'.

[0135] A semi-transparent film pattern 2a is formed in the opening SL', and a semi-transparent film remaining portion 2r is formed below the extension portion 16e' as in Fig. 22(B). However, the semi-transparent film 2 may be further over-etched to remove the semi-transparent film remaining portion 2r. FIG. 25(D) is a cross-sectional view of the bridge region in FIG. 25(C) and corresponds to the cross-sectional view in FIG. 22(B).

[0136] Next, as shown in a plan view of FIG. 26(A), a cross-sectional view of FIG. 26(B), and a cross-sectional view of FIG. 26(C), the coating film pattern 11a and the eighth photoresist pattern 16a′ are used as an etching mask. 1. The light-shielding film pattern 3a is etched selectively with respect to the semi-transmitting film 2 and the covering film 11, and the light-shielding film line pattern 3L having the width WL is removed. At this time, the side walls of the first isolated light shielding film pattern 3j and the second isolated light shielding film pattern 3k are side-etched and retreated, so that the first isolated light shielding film pattern 3j and the second isolated light shielding film pattern 3k are reduced to become the first isolated pattern 3m and the second isolated pattern 3n, respectively. By making the amount of etching equal to the extension distance D', both ends 2E of the semi-transparent film pattern 2a become flush with the sidewall surfaces of the first isolated pattern 3m and the second isolated pattern 3n. The cross section of Fig. 26(B) corresponds to the cross section of Fig. 25(D). Fig. 26(C) is a cross section taken along line C'-C' of Fig. 26(A).

[0137] Next, as shown in the cross-sectional views of Figures 27(A) and 27(B) and the plan view of Figure 27(C), the coating film pattern 11a is selectively etched with respect to the semi-transmitting film 2 (semi-transmitting film pattern 2a) and the light-shielding film 3 (first isolated pattern 3m and second isolated pattern 3n). The semi-transmitting film pattern 2a made of the semi-transmitting film 2 and the first isolated pattern 3m and second isolated pattern 3n made of the light-shielding film 3 are not etched. On the other hand, by removing the coating film line pattern 11L, the semi-transmitting film remaining portion 2r formed thereon is also removed.

[0138] 27(D), the eighth photoresist pattern 16a' is removed. The semi-transmitting film pattern 2a, the first isolated pattern 3m, and the second isolated pattern 3n correspond to the bridge pattern 63c, the first isolated pattern 61c, and the second isolated pattern 62c.

[0139] The semi-transparent film pattern 2a constitutes a bridge pattern that electrically connects the first isolated pattern 3m and the second isolated pattern 3n. The width w of the semi-transparent film pattern 2a is set to a value equal to or less than the resolution limit of the lithography process, so that it is not transferred to the exposure target. In addition, since the bridge pattern is made of the semi-transparent film 2, it also has the effect of preventing or reducing the risk of shape abnormalities occurring near the isolated pattern due to the above-mentioned proximity effect. [Industrial Applicability]

[0140] According to the photomask manufacturing method of the present invention, a photomask capable of preventing electrostatic breakdown between isolated patterns can be obtained. Moreover, it is highly compatible with not only binary masks but also halftone masks and phase shift masks, and has high industrial applicability. [Explanation of symbols]

[0141] 100 Photomask 10 Photomask blanks 20 Photomask blanks 1 Transparent substrate 2 Semi-permeable membrane 2a Semi-permeable membrane pattern 2b, 2c, 2e Semi-permeable membrane overlap section 2d, 2f Semi-transparent film pattern 2r Semi-transparent membrane remainder 2E End 3. Light-shielding film 3a First light-shielding film pattern 3b Second light-shielding film pattern (first isolated light-shielding film pattern) 3c Third light-shielding film pattern (second isolated light-shielding film pattern) 3d, 3j, 3m First isolated light-shielding film pattern 3e, 3k, 3n Second isolated light-shielding film pattern 3f, 3g, 3h Light-shielding film pattern 3L Light-shielding film line pattern 4. First photoresist film 4a First photoresist pattern (first etching mask pattern) 4s opening (opening pattern) 5 Second photoresist film 5a Second photoresist pattern (second etching mask pattern) 5f Filling section 5e Extension part (cover part) 51a, 51b, 51c First isolated pattern area 52a, 52b, 52c Second isolated pattern area 53a, 53b, 53c Bridge Area 61a, 61b, 61c First isolated pattern 62a, 62b, 62c Second isolated pattern 63a, 63b, 63c Bridge Pattern 7 Interlayer 7a First intermediate film pattern 7b Second intermediate film pattern 7c Third interlayer pattern 8. Third photoresist film 8a Third photoresist pattern 9a, 9c Semi-transparent area (halftone area) 11 Coating membrane 11a, 11b Coating film pattern 11c, 11d, 11e Coating film overlapping portion 11L Coating film line pattern 11j First isolated coating film pattern 11k Second isolated coating film pattern 12 Fourth photoresist film 12a, 12b Fourth photoresist pattern (light-shielding area etching mask) 13 The fifth photoresist 13a, 13e Fifth photoresist pattern (semi-transparent area etching mask) 13b Central part 13c, 13d, 13f overlapping parts 14 The 6th Photoresist 14a Sixth photoresist pattern 15 The 7th Photoresist 15a, 15a' Seventh photoresist pattern 15L, 15L' line section 15s, 15s' Space Section 16, 16' 8th photoresist 16a, 16a' Eighth photoresist pattern 16c, 16c' central part 16e, 16e' extension OP Opening d Expansion width D Projection distance D' Extension distance SL, SL' Opening (slit) STa laminated pattern

Claims

1. A method for manufacturing a photomask having a first isolated pattern (61a), a second isolated pattern (62a), and a bridge pattern (63a) connecting the first isolated pattern (61a) and the second isolated pattern (62a), A laminated film formation step of forming a semi-transparent film (2) having conductivity on a transparent substrate (1) and a light-shielding film (3) on the semi-transparent film (2); a first etching mask forming step of forming a first resist pattern (4a) having an opening pattern (4s) on the light-shielding film (3); a first patterning step of selectively etching the light-shielding film (3) to form an opening (OP) and removing the first resist pattern (4a); a second etching mask formation step of forming a second resist pattern (5a) on the light-shielding film (3), the second resist pattern (5a) having a bridge region (53a) covering the opening (OP), and a first isolated pattern region (51a) and a second isolated pattern region (52a) in contact with the bridge region (53a); a second patterning step of etching the light-shielding film (3) and the semi-transmitting film (2) to form the first isolated pattern (61 a), the second isolated pattern (62 a) and the bridge pattern (63 a), and removing the second resist pattern (5 a); A method for manufacturing a photomask, comprising:

2. 2. The method for producing a photomask according to claim 1, wherein a width (w) of the opening pattern (4s) is equal to or smaller than a resolution limit of an exposure process using the photomask.

3. In the first patterning step, 2. The method of claim 1, further comprising the steps of: exposing said semi-transparent film; etching said semi-transparent film to reduce its thickness;

4. The bridge region (53a) of the second resist pattern (5a) is 2. The method for manufacturing a photomask according to claim 1, further comprising: a filling portion (5f) that fills the opening (OP); and an extension portion (5e) that protrudes from the filling portion (5f) and covers the light-shielding film (3).

5. The second patterning step includes: A step of selectively etching the light-shielding film (3); Selectively etching the semi-transparent film (2); 5. The method for producing a photomask according to claim 1, further comprising:

6. In the laminate film forming step, An intermediate film (7) is further formed on the semi-transparent film (2), and the light-shielding film (3) is formed on the intermediate film (7); In the first patterning step, selectively etching the light-shielding film (3), and then selectively etching the intermediate film (7) to form the opening (OP) exposing the surface of the semi-transparent film (2); In the second patterning step, 5. The method for manufacturing a photomask according to claim 1, further comprising the steps of: etching the light-shielding film (3), the intermediate film (7) and the semi-transparent film (2) to form the first isolated pattern (61 a), the second isolated pattern (62 a) and the bridge pattern (63 a).

7. A method for manufacturing a photomask having a first isolated pattern (61a), a second isolated pattern (62a), and a bridge pattern (63a) connecting the first isolated pattern and the second isolated pattern, a light-shielding film forming step of forming a light-shielding film (3) on a transparent substrate (1) and a covering film (11) made of a material different from that of the light-shielding film (3) on the light-shielding film (3); forming a light-shielding region etching mask (12a, 12b) on the coating film (11); a light-shielding film patterning step of etching the coating film (11) and the light-shielding film (3) to form the first isolated pattern (61a) and the second isolated pattern (62a) and removing the light-shielding region etching masks (12a, 12b); A semi-permeable membrane forming step of forming a semi-permeable membrane (2); a semi-transparent film patterning step of forming a semi-transparent region etching mask (13a) on the semi-transparent film (2), etching and patterning the semi-transparent film (2) and the coating film (11) using the semi-transparent region etching mask (13a) as an etching mask, and further removing the coating film (11) by overetching to form a bridge pattern (63a) made of the semi-transparent film (2), and removing the semi-transparent region etching mask (13a); A method for manufacturing a photomask, comprising:

8. A first isolated pattern (61a) and a second isolated pattern (62a) are provided on a transparent substrate (1), and a bridge pattern (63a) connecting the first isolated pattern (61a) and the second isolated pattern (62a), the first isolated pattern (61a) and the second isolated pattern (62a) are formed by laminating an upper layer film having a light-shielding property and a lower layer film having a semi-transparent property, The bridge pattern (63a) is conductive and semi-transparent, and is connected to the lower film; The photomask is characterized in that the transmittance of the bridge pattern (63a) is higher than the transmittance of the underlying film.

9. The lower membrane is made of a semi-permeable membrane (2), 9. The photomask according to claim 8, wherein the bridge pattern (63a) is made of a reduced thickness of the semi-transparent film (2).

10. The bridge pattern (63a) is made of a semi-transparent film (2), 9. The photomask according to claim 8, wherein the underlayer film is a laminate of the semi-transparent film (2) and an intermediate film (7) formed on the semi-transparent film (2).

Images